BSCI473 Exam 3

community (dis)assembly rules in coral reefs

(a) assembly: - both past and present assemblages not a result of random processes - predictable: the composition of Pleistocene coral communities in Barbados, over time based on species specific growth rates - reef fish assemblages are adaptive to their respective environments (b) disassembly - non-randomly by environmental change - species that survive photobleaching tend to have thicket tissues and higher mass transfer - "champagne" reefs: persist in naturally acidic waters by percolating volcanic CO2 seeps, while branching corals are far less abundant on nearby reefs unaffected by the CO2 seeps

predicted changes in range and phenology

- "climate envelope" models (CEMs): statistical relationship between the abundance of a species and underlying climate variables, typically annual mean temperature; no assumptions about the processes driving this relationship; makes predictions about past and future change; null models against which observed shifts can be compared - velocity of climate change: ratio of the long-term trend in the climate variable to the local spatial gradient in that climate variable, and the direction is given by the direction of the local gradient; highly variable across the ocean

processes at seagrass patch edges

- "settlement shadow" of higher larval settlement at patch edges - increased nutrient uptake at patch edges; reduced physical disturbance within the canopy - seagrass growth and distribution patterns mediate predator-prey interactions - predator abundance does not always vary from patch edge to interior - seagrass landscape effects are best studied with bivalves, focusing on bivalve recruitment, growth, and survival

order scleractinia (stony corals) symbiosis with dinoflagellates: brood

- (b) brood: zooxanthellae passed from adult coral to egg during gametogenesis - embryo (planula) develops within adult gastrovascular cavity, crawls away, usually settles nearby

reef survival

- 3 factors that determine reef survival: rates of = (1) land subsidence, (2) sea level rise, (3) reef growth - depth of the granite mountaintop of Enewetak Atoll (Marshall Islands) is 4,158-4,610 feet beneath the carbonate cap--but Enewetak is still a living atoll - this means that the rate of coral growth has been able to keep up with the rise of land subsidence and/or sea level rise at Enewetak - if the reef "drowns" = a "drowned atoll" is called a "guyot" - dead coral heads found ~1,000 m deep in the NW Hawaiian & Emperor Chain

invasive species of seagrass communities

- 56 non-native species introduced to seagrass beds worldwide; contribute to seagrass decline - there was a relatively low number of introduced consumers which may be due to high abundance and diversity of native seagrass consumers - introduced consumers negatively affect seagrasses other than by consumption (disturbance) - more evidence for top-down control

trawling

- 75% of the ocean's continental shelf has been trawled or dredged at least once - modern trawls about 10-25 m wide and are used primarily to catch flatfish (halibut), groundfish (cod), shrimp, and crab - dredges cause significant damage as they dig into the substrate dislodging many of the benthic organisms and suspending sediment

types of fisheries

- 78.6 million metric tons reported (legal); ~11-26 million metric tons unreported (illegal) - reported landings of marine & freshwater fish increased more than fivefold between 1950 and 1998 - ~7 million metric tons of unintentional bycatch per year - conservative best estimate for total removal of marine life from ocean by all forms of fishing = ~100 million metric tons

threats to marine communities

- 96% of local extinctions in coastal environments involved fishing and hunting - 39% involved habitat degradtion - concepts and theories developed from terrestrial, freshwater and coastal ecosystems --> application to continental shelf and deepwater habitats - fisheries with a historically "single-species focus" require broader community context in order to fully understand impacts - EAF (ecosystem approach to fisheries): management framework incorporating interactions among marine organisms and fisheries

micro-borers or micro-bioeroders

- EX: cyanobacteria, unicellular and simple multicellular green algae, fungi, foraminifera - these bore into coral and reef basement for protection from predation/grazing - soften the substrate--facilitate invasion by internal bioeroders and grazing/chomping by external grazers

scrapers or external bioeroders

- EX: sea urchins, herbivorous and predatory fishes - create 3D microhabitat responsible for high reef diversity - scrape/chomp/crush calcium carbonate substrate in their feeding activities - create larger excavated holes, caverns, overhangs in reefs - allows refuges for larger organisms - further increase the structural complexity and diversity of microhabitats in the reef - may cause large scale erosion of the reef framework (i.e. during urchin outbreaks) * most important destroyers of reef substrate * most important sediment-producers on the reef--> favors reef cementation --> most important factor in reef growth

grazer driven die-offs

- North: experimental work on die-offs in southern New England in salt marshes is attributed to run-away herbivory by the native, nocturnal purple marsh crab - South: significant recovery began in marshes with the longest and most intensive histories of die-off; compensatory predation: the fear of being eaten by an invader is depressing the density and top-down effects of this problematic grazer and aiding in the recovery of Spartina in Cape Cod

observed changes in ranges and phenology

- Sorte calculated a mean rate of range shift of 190 km per decade, much higher than the median value for velocity of climate change (21.7km/decade); could be due to the tendency for only positive or notable shifts to be reported in the scientific literature (publication bias) - phytoplankton and zooplankton show the most rapid shifts, at 400 and 100 km per decade on average respectively - climate-related changes in phenology in the ocean are much less well-reported (difficult to sample and sustain effort)

larval dispersal and exchange in patchy, disturbed habitat

- active swimming may affect dispersal--some gastropods have been shown to actively swim downwards - eruptions may facilitate long distance transport of larvae

habitat loss and alteration

- affects primarily benthic habitat - fishing is one of the largest direct impacts on marine habitats alongside hurricanes and hypoxia - largest impacts caused by trawling - the use of explosive or poison to extract fish also causes significant damage to reef structure

ocean acidification

- approx. 25% of the CO2 emitted since the Industrial Revolution is now dissolved in seawater - when CO2 dissolves it forms H2CO3 - the pH of the ocean has fallen from 8.2 in 1750 to 8.1 in 2000 (30% increase in acidity)

assessing marine ecosystem resilience

- ecosystem resilience is necessary for long-term persistence of a full range of ecosystem services - abrupt and unexpected shifts in an ecosystem state are known as "regime shifts"

herbivory in coral reefs

- as consumers of benthic algae, herbivores directly affect the structure and composition of benthic communities - fishing of herbivorous fishes alters the structure of the herbivore community by disproportionately reducing biomass of large bodied functional groups - main consumers of primary production include: fishes and urchins - herbivores function on reef depending on feeding mode: grazers, scrapers, bioeroders - herbivorous fishes consume benthic primary producers and regulate competition between fleshy algae and reef-building corals - diverse communities of herbivores are necessary to maintain important ecosystem functions on coral reefs

facilitation among plants

- at low marsh elevations, plant neighbors aerate oxygen-poor sediments within their aerenchyma, benefiting neighboring plants - at higher marsh elevations, plant neighbors shade the substrate and prevent evaporation of surface porewater, which causes salt to accumulate and stress plants - this facilitation is important in secondary succession after disturbance

evolutionary history of boring: bore into substrate for protection from predators

- began in Paleozoic in early non-scleractinian "reefs" as body size, activity level, and predation increased - intensified with the Mesozoic revolution--the rise of modern morphologically complex predators - predation drove epifauna (worms, sponges, bivalves, etc.) into relatively soft calcareous reef substrate--drilling/boring to make holes in substrate, refuge from predators - creates 3D microhabitat--responsible for high reef diversity * predation --> boring --> 3D microhabitat - after bioeroder dies, leaves empty hole - sessile and mobile epifauna crowd into empty bioeroded holes to avoid predation - competition for space drives morphological diversification in cryptofauna - constant predation pressure continues to drive morphological diversification in cryptofauna - restricted to small body size by size of available refuge space --> low fecundity, low dispersal --> high speciation

what are ecosystem services?

- benefits humans obtain from ecosystems - quantitative assessment: ecologists and economists map ecosystem structure and function to specific benefits - human impacts on ecosystems affect structure and function of an ecosystem, and can therefore impact ecosystem services

physical disturbance on benthic community structure

- benthic communities normally experience relatively low levels of disturbance - dominated by strong competitors that are larger, older and have long generation times - when these communities are disturbed intensely or frequently, the late-successional species are replaced by highly mobile demersal fishes and invertebrates - these animals, usually scavengers, attack the organisms displaced or damaged by fishing gear - these worm-like, nematodes are weak competitors with little defense but they are tolerant of pollution and hypoxia, which commonly occur in highly disturbed areas - 3 factors that determine the extent to which a benthic community is modified by bottom-disturbing fishing gear: (1) frequency of fishing disturbances, (2) frequency of natural disturbances, (3) the type of bottom substrate, not particle size

species interactions on hydrovents

- biotic interactions also important, but occur within livable abiotic environment - competition more frequent with more species, higher temperatures in center of habitat - facilitation more frequent with less species, lower temperatures at edge

antipatharia

- black or thorny corals - now thought to be allied to the zoantheria (hexacorallia) - skeleton may be black, red, orange, brown, green, yellow, gold, or white - live in deep water (50- >450 m) - feed on plankton - grow very slowly, some >4,000 years old - deposit minerals in their skeleton, responsible for the color (hard = jewelry) - provide structure for diverse community (fisheries) - many symbionts: wire coral shrimp, wire coral spider crab, camouflaged hawkfish

types of hydrovents

- black smokers: abyssal and hadal zones because the water around these structures are rich in H2S which is black; hottest - white smokers: surrounding water contains barium, calcium, and silicon which are white; not as hot as black smokers

what happens when symbiosis breaks down? proximate causes

- bleaching - proximate causes of bleaching: zooxanthellae bails out, coral expels zooxanthellae, zooxanthellae dies

importance of coastal vegetation for climate change

- blue carbon (coastal carbon) covers small portion of Earth, but has a large effect on the global carbon cycle - sequesters carbon at a far greater rate (50-100X faster) and more permanently than terrestrial forests - coastal vegetation can spread rapidly via clonal propagation - marine wetlands release very little methane (unlike freshwater and bogs)

zonation

- borders are determined by stressors via latitudinal variation - high latitude: lower borders determined by waterlogging and anoxia; higher borders determined by competition - low latitude: borders determined by salinity stress from solar radiation evaporation

internal bioeroders or macro-borers

- boring sponges, clams, worms, barnacles - bore into coral and reef substrates for protection from predation (capable of excavating hundreds of kg/m^2/yr) - this is where much of the same on tropical beaches and lagoons comes from * internal bioeroders are the most important drivers of high diversity on coral reefs * most of the biodiversity on reefs is cryptofauna

population-level approaches: relocate and concentrate juveniles and adults

- can increase local population abundance - potential for disease introductions - reduces early post-settlement mortality, but not mortality for adults - these types of approaches only work if larval supply or early post-settlement mortality is the population bottleneck

geographic scope of small scale experiments

- canopy removal experiments increased barnacle survival by reducing predation - two studies indicate the strength and outcome of species interactions can vary over multiple scales

Paper: Community Regulation: Under What Conditions are Bottom-Up Factors Important on Rocky Shores?

- case study in Oregon - predator density and prey abundance, recruitment, mortality, and growth were all highest at Strawberry Hill (SH) exposed sites - more food at SH exposed sites - mussel mortality rate and pisaster density directly correlated: suggests site differences not caused by variation in predation intensity, diets, or competition with other predators - more prey leads to more predation intensity, so more top-down control

ocean warming

- occurring at all levels since 1980s - West coast of America has actually cooled slightly - Southwest Pacific is heating quicker than global average

community-level affects of climate change

- changes in community richness, composition, and functioning - prey will soon be introduced to new predators against which they have no evolved defenses - ocean warming will lead not only to new consumers, but also to hungrier ones: by increasing warming, activity and metabolic demands of predators will be higher - calcified structures are often used as a defense against predation, and a weakening of these structures may increase susceptibility to predators - growing number of documented examples in which water temperature and disease severity are positively related - altering the roles of mutualisms and other forms of facilitation

changes in geographic ranges and phenology

- climate change puts a proportion of the global population of a species outside their thermal range and bring new areas into the range of places where the species can live - notable exceptions are animals that control their internal body temperature which are mostly marine and birds - some organisms change their geographic distribution to remain in optimal thermal environment; changes the geographic location of the species fundamental niche

oceanographic drivers of rocky intertidal community structure

- coastal features influence propagule dispersal, recruitment intensity, and nutrient supply - nutrient "pulses" important where upwelling occurs --> nutrients brought onshore during relaxation events - in 1980s and 1990s most in field thought top-down and bottom-up did not occur simultaneously

salt marshes

- coastal wetlands that are flooded and drained by salt water brought in by tides - natural filters that intercept and process terrestrially derived runoff before it enters nearshore coastal systems

competition: algae and coral

- competition common due to benthic location - algae effects are detrimental and physically cause shading and abrasion leading to tissue loss and mortality - aggressive mechanisms: chemical and biological warfare (release of allelochemicals that can cause bleaching), transfer microbes including pathogens directly to corals, and enhance microbial growth via water soluble compounds

human eutrophication

- competition: increased N switches dominant species hierarchy - invasives: more dominant when there is an increase in N - increase in N lowers diversity and increases palatability of plants; herbivory increases as the plants taste better

prospects of conservation and management

- conservation efforts mainly driven by reef's economic contributions--global value estimated at US $30 billion annually - increasing reef resiliency is a major goal of conservation efforts--new growth and recruitment must exceed the rate at which coral death occurs - crucial parts of successful management: managing local stressors - many people look towards a singular fix for one problem: coral farming, assisted migration (moving fragments from healthy to desolate areas to try to increase recruitment), freezing coral gametes to repopulate if all reefs die off - in the end, we must address the root of the problem--increasing levels of atmospheric CO2

why are hydrovents important?

- contain unusual organisms that have adapted extreme conditions - provide nutrients to surrounding ecosystem - sustain complex food webs - nutrient cycling - reservoir of knowledge

predation on coral reefs

- coral predators have the ability to greatly decrease coral populations - the Crown of Thorns Sea Star is the most notorious predator--responsible for almost half of the decline of coral cover on surveyed reefs - bottom up: nutrients made more abundant by agriculture cause initial outbreaks by increasing food force for sea star larvae - reductions in outbreaks associated with MPAs--suggesting that outbreaks are favored by sea star predators caused by overfishing - effects of predators are more common in the Pacific

local decline of corals: invasive species

- coral reef species are very specialized and resilient: very few non-native species found in diversity surveys - lionfish in the Caribbean reduce recruitment and abundance of native small fish - red algae in Hawaii forms large mats that block light

Paper: Climate change disables coral bleaching protection on the Great Barrier Reef

- corals and their endosymbiotic symbiodinium (zooxanthellae) acquire a thermal tolerance following exposure to sub-lethal pre-stress thermal events: protective trajectory - corals that experience a single, steadily increasing or multiple, repetitive thermal trajectories do not develop thermal tolerance--observed poorer physiological outcomes = larger % cell death and loss of zooxanthellae - assumed increasing sea surface temperatures (SST), predicted catastrophic impacts on the Great Barrier Reef: protective trajectories will become less frequent; single trajectories will become more frequent

seagrasses as foundation species

- create entirely new types of substrate - structure above and below ground: allows support of a wide variety of invertebrates, fish, birds, and mammals - host higher animal densities than any other soft-bottom community - higher abundances, growth and survival or animals than unstructured habitats - considered "nursery" habitats: supporting many organisms only at early life stages

extinction due to climate change

- depending on how quickly and by how much the oceans warm and acidify due to climate change, countless populations and some species will fail to adapt, acclimatize, or move and will simply go extinct - well over 100 species were predicted to be lost in the next few decades - paleontological record on how past regional and global climate shifts affected extinction rates and which taxa were most susceptible - extinction-prone coral species of the present are related to susceptible species from past geologic eras

Alfred Redfield

- described ontogeny of New England salt marsh: identified salt marshes as biogenic communities built and maintained by foundation species

population-level approaches

- different restoration approaches: restrict harvest, create spawning sanctuaries, introduce reared larvae, relocate and concentrate juveniles and adults, habitat conservation and restoration - the approach used depends on the current population bottleneck - EX: introducing reared larvae will have little to no effect if the population bottleneck is later post-settlement mortality

modification of the environment and of biotic interactions

- dominated by a small number of foundation species - many inhabitants facilitate other species --> facilitation cascades - reciprocal facilitation= form of mutualism - complex mutualisms involving third parties (including microbes)

regime shifts and feedback mechanisms

- ecosystems absorb disturbances up to a tipping point and shift rapidly into a new state that functions and responds to pressures differently - difficult to shift back to original state - feedback mechanisms tend to maintain the system in the undesired state - seagrass beds do not return to sediments from which they have already been lost - many coastal seagrass beds have been replaced by mats of ephemeral micro and macroalgae - nutrients released from decaying plant detritus accumulate in sediments to stimulate blooms of ephemeral algae even after conditions improve - two stable states are (1) seagrass beds or (2) benthic micro- and macroalgal beds

quantifying the role of biodiversity in supporting marine ecosystem services

- effects of human activities on marine ecosystems include loss of diversity - important services (such as productivity of fisheries and maintenance of water quality) decreased with declining diversity - more diverse large marine ecosystems (LMEs) had fewer collapsed fisheries and higher rate of recovery than less diverse LMEs

colonization and succession

- eruptions are volatile and violent, eradicate resident fauna, and alter the physical and chemical environment - eruption cycles of vents establishes the colonization and succession rotations of the community - vent H2S levels dip as in the months and years leading up to an eruption - foundation species facilitate the community growth around the vent - scientists still deliberating whether facilitation is a direct effect through surface bound chemical settlement or whether it's an indirect effect from the interaction with microbial biofilms - recovery is rapid and communities will return to full strength only 2-3 years after an eruption - eruptions give the opportunity for species previously unfound in that area to establish themselves and flourish in the community

coral biodiversity

- estimation methods are used to determine the number of species - extrapolation: calculations based on rate of discovery - coral reef diversity calculated based on estimated proportions of marine species living in or on coral reefs - varying results can imply smaller or larger numbers of reef-associated species

conservation of vent communities

- ever since its discovery, scientists have been exploiting these communities by harvesting and manipulation of vents in order to gain data - recently, mining of deep sea vents has become possible in order to extract precious earth like cobalt, gold, and copper to use in high-tech manufacturing - two main aspects of vent communities: (1) communities resiliences to disturbances, (2) connectivity to other locations - many strategies: (1) currently the Antarctic vents south of 60 degrees S benefit from automatic conservation under the Convention on the Conservation of Antarctic Marine Living Resources and the Antarctic Treaty; (2) MPAs are where most of the vents are located

distribution of vent species

- extreme environmental/abiotic gradients are a strong influence; especially temperature gradient - # microbes increases near center, decreases at edges

Paper: An extreme climatic event alters marine ecosystem structure in a global biodiversity hotspot

- extreme warming event along the west coast of Australia in 2011 - benthic and fish communities experience significant structural shifts attributed to: reduced cover of kelp and encrusting coralline algae and sponges; increased cover of turf-forming algae - most likely causative agent for decreasing total cover of macroalgae canopy is anomalous warming that exceeded physiological thresholds - subtidal habitat-forming seaweeds normally outcompete turf-formers, but a reduction in canopy cover reversed this - warm-water species appeared - tropicalization of fish communities indicated stronger poleward flow of the Leeuwin current - demonstrates important of biogeography and thresholds

coral defenses against competing coral

- feeding tentacles of polyps can transform into enlarged sweeper tentacles up to 6.5 cm long - feeding tentacles are used to detect and repel competing corals - can cause damage to soft tissue and polyp mortality - response not rapid

direct effects: extinction risk

- few marine species driven to global extinction in modern times - IUCN Red List: most comprehensive source of information on threatened and extinct species - extinct marine species mostly birds, mammals, and molluscs - conceivable that significant numbers of marine invertebrates have gone extinct without anyone noticing - no truly marine fish species have gone extinct (multiple freshwater have) - particularly high for large bodied, slow-growing species: more vulnerable to fishing gear, lower population abundance, lower resilience

Frederic Clements

- first described primary succession in New England salt marshes - (1) colonization of intertidal mudflats by cordgrass Spartina alterniflora (2) vegetative cordgrass growth and vertical accretion of peat and sediment (3) colonization by high marsh plants (4) woody plants

problems with restoration

- frame of reference: what time period do we choose to go back to? How do we know what the ecosystem was like before human disturbance? what site do we choose as a reference site? - accuracy of historical records or lack thereof - changes in the ecosystem that have occurred in the past and will continue to occur in the future - is it even possible to go back to older conditions given the new ecosystem?

what is climate change?

- greenhouse effect: caused by gases in the atmosphere absorbing infrared radiation - necessary for life on earth, but in moderation - atmospheric CO2 is expected to double in the next century from pre-industrial baselines - resulting warming of land is expected to be somewhere between 2 and 4.5C - sources of greenhouse gases: electricity use (29%), transportation (27%), industry (21%), commercial and residential (12%), agriculture (9%)

NCEs, food chains, ecosystem function

- growth efficiency is an important variable: can determine how much energy is transferred to higher trophic levels; can define the energetic status of organisms - found that green crab risk cues strongly reduce the flow of energy through food chain by reducing foraging and the conversion of energy once it is ingested - strong evidence that predation risk can shape prey energy budgets by increasing respiratory costs, production of heat shock proteins, and antioxidant enzymes

phase shifts and tipping points of corals

- replacement of corals by other sessile organisms and algae - rapid transition and hard to shift back - species extinction: no reef species globally extinct; 1/3 are at risk due to global warming + local stressors

direct effects of fisheries on benthic habitats

- habitat alteration by fishing gear perhaps the largest yet least understood threat to marine habitats since most areas had been trawled or fished historically before adequate baseline data was collected - these areas are also affected by natural disturbances, such as storms, which makes it even hard to quantify the effects from fishing - removal of biogenic and physical habitat structure - direct mortality - increased abundance of mobile predators or scavengers that feed on organisms injured or killed by fishing gear - reduction in the average size and lifespan of benthic organisms - increased abundance of small-bodied invertebrate species - decrease in the secondary production of benthic invertebrates and fishes in the affected area

classic metapopulation model

- habitat occurs in discrete patches - all populations have a substantial risk of extinction - dispersal occurs among all patches - patch dynamics are asynchronous - ignore population dynamics within a patch

recovering marshes

- harnessing the positive effects of clonal integration of Spartina can clonally recolonize stressful (anoxic) bare substrate

positive interactions on coral reefs

- has equal influence on coral reefs as competition and predation - mutualism: engine that drives the growth of corals - EX: symbiodinium (dinoflagellates) found inside the tissue of all reef-building corals provides host with food in exchange for nutrients - EX: cleaners remove substantial numbers of ectoparasites from hundreds of fishes -facilitative relationships: one benefits at no cost to the other - EX: damselfishes defend territories to protect the algal resources and nest sites within them to benefit territory owners - crustose coralline algae (CCA): provide substrate for attachment of many coral larvae and the distribution of CCA species that confers the best survivorship on young corals is a good predictor of coral recruitment rates across habitats

phylum cnidaria: hydrozoa

- has four living classes: hydrozoa, scyphozoa, cubozoa, and anthozoa - hydrozoa is paraphyletic: have both polyp (asexual, sessile) and medusa (sexual, motile), but polyp stage itself can be colonial and "polymorphic"

population-level approaches: introduce reared larvae

- hatchery production of larvae released into environment - currently used in the Chesapeake for oyster restoration - there is little evidence that this approach is effective for most marine species as later post-settlement mortality tends to be the greater threat - potential for disease introductions

zoantheria (hexacorallia): order actinaria

- have 6 extensions - order actinaria (anemones) - huge number of septa (multiples of 6): increased area for digestion and reproduction, increased support for body wall - complex musculature and behavior: predator avoidance (re-acquire mobility); aggressively fight for space: potent nematocysts on tentacles, clones and inducible, inflatable stinging structures called "acrorhagi"

alcyonaria (octocorallia)

- have 8 extensions - large polyps, plankton feeders - chemical defenses, many symbionts - especially important in deep water - soft corals, gorgonians, sea whips (tree-like soft corals, sea fans, sea whips, sea pens)

habitat-level approaches: seagrasses

- have been degrading at an accelerated rate over the last 20 years - limited success in restoration efforts - should only be attempted in places where the problem has already been addressed - it has become standard practice to test the restoration on a small scale plot first before starting a full blow restoration effort - much previous work is unpublished and/or difficult to access - hindered by site specific variables: unique herbivory, bioturbator community - since seagrass beds are almost exclusively monocultures, restoration attempts should maximize genetic variation because of the aforementioned benefits

predators in salt marshes

- having predator richness facilitates grasses and ecosystem functions - predator exclusion leads to marsh die offs

evaluating cumulative impacts

- helps managers to access the cumulative impacts of diverse human activities on ecosystem health - uses considered included renewably energy, sand and gravel mining, commercial shipping, commercial and recreational fishing, telecommunication infrastructure, and aquaculture - resources considered included both species and habitats of concern, particularly those that were unique and sensitive to human impacts - the five services most strongly affected by cumulative human impacts are: biodiversity, marine harvested species, aesthetic values, habitat and recreational values

landscape-level approaches

- high importance of these landscapes to predator-prey dynamics, recruitment, competitive interactions - these habitats tend to enhance each other

analysis of pattern at multiple scales

- higher variation occurs at small spatial scales, but the importance of large-scale variation is more species-specific - large scale variation becomes important as the spatial scale of sampling approaches the geographic limits of species distribution - important broad-scale spatial trends in the abundances of several algal and invertebrate species and changes in the spatial extent of key foundation species -

the state of coral reefs

- historical accounts suggest modern reefs are shadows of their former selves - decline from about 50% coral cover in the mid-1970s to just 10% at the turn of century in Caribbean) - corals can retain their structure for some time after their death - local and global stressors: overfishing, runoff, invasive species, CO2

habitat-level approaches: mangroves

- historically exploited for lumber and organisms associated with them - cleared from coastlines to make room for resorts and aquaculture - mangrove restoration efforts historically focus on just a few types of vegetation - mangrove planting on previously unvegetated mudflats usually fails - loss of mangroves is often associated with lower fin fish fisheries success and lower wild shrimp harvest success - success of mangrove restoration efforts can be roughly measured by relative health of benthic assemblages - heavy consumption of mangrove faring invertebrates (crabs, prawns) is often correlated with negative effects in offshore food webs - symbiotic relationships can promote mangrove growth

ecosystem-level approaches

- required to address problems such as: changes in hydrology of watersheds and estuaries, chronic pollution and nutrient input, shoreline development - most projects focus on restoring connectivity between estuaries and nearshore marine environments - smaller scale habitat restoration efforts can work together to solve ecosystem-level goals

order scleractinia (stony corals) symbiosis with dinoflagellates: broadcast

- how do corals acquire the symbiotic dinoflagellates? - (a) broadcast: adult coral releases thousands/millions of tiny eggs or sperm to be externally fertilized in the water column - externally fertilized zygote --> swimming planula --> settles - zooxanthellae invade through mouth/gut or invade through exterior epithelium - then zooxanthellae are taken up by phagocytosis, undergo asexual reproduction inside the cell, cells divide = zooxs passed to other cells

loss of ecosystem services

- human disturbances are negatively impacting salt marsh coverage and the structure of these ecosystems - no longer can marshes be championed as systems that can and should be used to buffer human impacts

introduction to hydrovents

- hydrovent: a hydrothermal vent; a crack in the planet's surface where geothermally heated water can leave - deep sea hydrovents arise in all ocean basins and usually form at mid-ocean ridges--where two tectonic plates diverge and a new crust is being formed and on volcanic arcs made at subduction zones--where two tectonic plates meet and one plate is forced below another - water that is issued out from hydrovents consists mostly of the ambient seawater that is drawn into the hydrothermal system at mid-ocean ridges or subduction zones - the cold water is heated by magma and reemerges as well as porous sediments - when the superheated water hits the near-freezing water of the ocean, the minerals dissolved into the fluid will precipitate out to form particles and accumulates

Paper: Anticipative management for coral reef ecosystem services in the 21st century

- identified 14 ecosystem services: aquaculture, aquarium trade, biotechnology, carbonate budget, fisheries, habitat provisioning, nutrient cycling, primary production, sand production, recreational fisheries, shoreline protection, species richness, tourism, water quality control - identified 6 management strategies: marine reserve, artificial complexity, herbivore fishing ban, herbivore fishery, coral restoration, pelagic FAD - direct and indirect changes in abundance of coral reef functional groups in response to five of the management strategies

zonation and community organization of intertidal rocky shores

- importance of strong vertical, horizontal gradients caused by physical forces - physiological, morphological, behavioral adaptations to stressful conditions - trade-offs are accepted as creators of max lift and drag organisms can withstand

ecosystem services provided by seagrass communities

- improve water quality and reduce erosion - blue carbon and nutrient sequestration - constitute a critical nursery and feeding habitat for economically important species of fish and shellfish

sea-level rise

- in many areas, marshes are blocked in with no way to expand landward due to human development - top-down predator depletion are eliminating the foundation species that build marshes

challenges to quantification

- inadequate knowledge of link between ecosystem structure/function and production of goods and services - some services are direct, easily measurable - others are harder to estimate, benefit humans without input

marine protected areas

- incorporate extensive areas of undisturbed terrestrial borders to buffer marshes from extensive eutrophication via runoff and allow for their landward migration as sea levels rise - must allow for the inclusion of positive interactions at all levels of biology

Paper: Novel index for quantification of ecosystem effects of fishing as removal of secondary production

- index showed high classification success of previously classified ecosystems (80%) - secondary production loss (L) allows for the assessment of ecosystems based on relatively few inputs - success of future management efforts can be predicted and tested

the community consequences of predation risk

- inducible defenses are common in rocky shore species and have been documented in a number of traits - EX: snail shell thickness, shell color, adductor muscle size, byssal thread production, barnacle shell shape, chemical defenses of algae

hydrothermal vent paradox

- it was observed that the palm worm had a homogeneous genetic structure across many hydrothermal vent sites, despite having an extremely limited dispersal potential - using general metapopulation models that include extinction and recolonization, scientists were able to find that the character of dispersal, interacting with habitat dynamics, determines the extent of genetic divergence between populations

traits of individual plants

- leaves, rhizomes, and roots of seagrasses modify currents and waves = traps and stores sediments and nutrients

effects of removing blue carbon sites

- loss of blue carbon habitats means loss of their sequestration function - conversion of blue carbon sites --> releases stored carbon in the form of greenhouse gases - aeration may lead to the release of carbon that has been locked up for centuries or millennia - aeration leads billions of tons of carbon emissions annually

climate change and ocean ecosystem services

- loss of species and entire ecosystems - loss of income from lack of tourism - loss of reefs especially adjacent to coastal community means reduced buffering from waves and increased shoreline erosion - direct and indirect effects on fishery production

other forms of habitat disturbance

- loss of wetlands by land reclamation, coastal development, pollution, and eutrophication - rocky shore habitats and coral reefs threatened by sedimentation from terrestrial runoff, beach development, dredging - species invasions, tourism, shipping affects most habitats - aquaculture, the most rapidly growing food sector, involves some degrading practices such as replacing mangroves with shrimp farms - result of all these activities is that the marine environment is becoming less heterogenous and there's less structurally complex physical habitat

herbivory

- low latitudes: more intense predator-prey interactions lead to an increase in defense through palatability - higher chemical defense in southern plant species; grazers prefer northern vegetation - increase in rodent grazers increases plant diversity - tunneling by field mice slows down secondary succession of bare patches and inhibits growth of invasive animals

quantifying and valuing marine ecosystem services

- mangrove forest conversion to shrimp farms has led to considerable loss of valuable ecosystem services in Thailand - Louisiana Master Plan for Coastal Restoration and Protection - local investment in building resilient coastal communities in California

experiments

- marsh plant transplant experiments that examined mechanisms maintaining the distinct patterns of plant zonation aligned perpendicular to incoming tides showed that salt marsh plants did not necessarily live where they grew best, as if physical or bottom-up processes were in control - instead, transplant experiments in New England revealed interspecific competition largely dictated the conspicuous segregation of different plant species across marsh zones - new explanation for plant zonation in which intense competitive interactions hierarchically organize plant species along environmental gradients according to interspecific differences in competitive ability and stress tolerance - later experiments revealed that both intra- and interspecific positive interactions esp. facilitation among plants is also important

trophic cascades on coral reefs

- may be difficult to detect - "fear effect" predators cause shifts in prey behavior through the risk they impose (spend more time hiding, find less risky habitats) - behavioral change in herbivores can result in changes in their demography - trophic cascades may ultimately be context dependent at sites: can be top-down or bottom-up control

coral defenses against algae

- mesenterial filaments - filaments loaded with nematocyst, that are used to digest prey - may occasionally allow corals to inhibit algal growth - also used with competitive interactions when neighboring coral of different species comes too close

metacommunity dynamics of vents

- metapopulation: a group of geographically separated populations, each of which is subject to extinction and connected to others by migration, so that dynamics in one population can potentially affect dynamics in others - metacommunity: an expansion of the metapopulation concept to include multiple species and their interactions - global species distributions are important for understanding diversity among vents - all biogeographical provinces of vents host a characteristic fauna that describes their general appearance

Paper: Accounting for Multiple Foundation Species in Oyster Reef Restoration Benefits

- microalgae clearance: trends similar for both species, oysters cleared better in higher temps; in winter months both bivalves have similar efficiencies - picoplankton clearance: mussels have higher efficiency in clearing picoplankton; mussels were 88% efficient while oysters were 45% efficient - no correlation found between oyster and mussel abundance, but more bivalves were found in areas where restoration efforts were underway - adding mussel filtration into oyster control more than doubled phytoplankton control on average - current restoration increased phytoplankton control 2.5 fold - increasing reef size gives greater control, mussels taking up large portion of that control

Georgia Sea Islands

- modern salt marsh ecology began here - bottom-up energy flow in salt marshes controlled the function and structure of these systems - major paradigm: the abundance, distribution, and productivity of organisms in ecosystems were regulated by energy flow within a food web and that physical forces (nutrients, physical factors, tides) mediated the production of that energy at the bottom of the web (bottom-up)

biodiversity and ecosystem functioning

- more diverse assemblages more resistant to invasion by invasives - functional group diversity more important than species diversity - more diverse assemblages recovered from stress more quickly - more richness led to less nutrient uptake by algal species - herbivory promoted recovery and succession - increasing richness inhibited succession when abundance was high - global warming causes species ranges to expand toward the poles - literature is probably biased in favor of a positive response to global warming

comparing predictions and empirical observations

- more rapid range shifting has occurred in areas where the velocity of climate change is greater - the majority (68%) of shifts have lagged behind the rates expected from shifting climate - species may adapt to the new thermal regime in their existing geographic range - climate debt = distance between the expected shift and the observed shift

direct effects: changes in composition and diversity

- more skewed fishing pressure = more pronounced shift in species composition - fished community over time will lose species with high catchability or low resilience to additional mortality - skewing of trophic structure - declining species richness

direct effects: changes in age and size structure

- most are size selective: large bait, large hooks = large mouthed fish - individual size correlated with age: some species' sizes correlate with other attributes such as longevity, growth rate - uneven exertion of fishing pressures across size classes drastically alters size and age structures: larger, older fish becoming more rare - size structure desirable from MSY perspective: smaller, faster-growing fish may be more productive and may survive better when larger predators are depleted

population-level approaches: restrict harvest

- most common conservation measure to rebuild stocks of overexploited fish - directly reduces fish mortality - does not work if the target species is not directly exploited - hard to accomplish because of public resistance and the potential economic losses to fishermen

invasive species

- naturally, salt marshes are difficult to invade due to high salinity - intentional planting of invasives is the main issue - EX: Spartina alterniflora planted for erosion control in China and California lead to displacement of migratory birds, bivalves, and native grasses

ocean solutions to climate change

- need to reduce our emissions of greenhouse gases - develop policies and technologies to remove those already emitted - reducing solar radiation would do nothing to mitigate ocean acidification

phylum cnidaria: anthozoa

- no medusa stage, only sessile adult polyp, but still both asexual and sexual phases - sexual phase: gametes --> motile larval stage (=complex life cycle) - asexual phase: sessile, often colonial (lateral growth = good competitor for space) --> coral reefs etc.

early experiments on biological interactions of intertidal rocky shores

- observed importance of consumer pressure, competition, biotic/abiotic control of distribution across gradients - important consumer removal experiments - manipulative experiments reveal patterns generated by disturbance - a "mosaic" of patches in different stages of succession - challenged Connell's view of "intermediate disturbance hypothesis" --> ecological systems are not at equilibrium, and more extreme disturbance levels promote diversity

habitat-level approaches: salt marshes

- oldest/first marine restoration effort - usually require large scale efforts to restore hydrology - planting of halophytic vegetation - some ecosystem conditions return quickly after restoration, while others take a much longer time to become established - plant species richness can be as low as 50% less than comparable undisturbed marsh, decades after restoration - well planned restoration takes into account complex relationships among species - restoring high native species diversity is a common goal - salt marshes are naturally resistant to plant invaders due to their hostile nature, but still have invasive problems

assessing trade-offs of ecosystem services

- one can use the ecosystem services lens to assess trade-offs among different management objects or human activities - MSP (marine spatial planning) could prevent over a million dollars in losses to the fishery and whale-watching sectors and could generate more than $10 billion in extra value for the wind energy sector - people in MA had a one-year intensive planning process to develop the first ever comprehensive ocean plan for the state's waters

latitudinal variation on mudflat pans

- pan: marsh patch continually without any dominant plant species - low latitude: pans with evaporated salt surface from intense hot climate - high latitude: pans are waterlogged suppressing plant growth

patch fragmentation

- patches range in size and shape due to clonal growth and sexual reproduction, biotic forces (grazing, bioturbation), and physical forces (hydrodynamics)

diseases on coral reefs

- play a more prominent role in the Caribbean--White Band Disease: presumed bacterial infection causes segments of bare skeleton, bordered by narrow bands of disintegrating, necrotic coral tissue - pathogens are more difficult to study than predators due to diversity of disease syndromes and causative agents of most diseases remain unknown - potential causative agents: nutrients and polysaccharides released by seaweeds & warm temperatures

ecological interactions of coral reefs

- predation - diseases - competition - herbivory - positive interactions - trophic cascades - community (dis)assembly rules

community ecology

- primary succession in salt marshes is limited by substrate instability, anoxia, and physical disturbance - both plant-plant and plant-animal positive interactions facilitate the initial establishment or successional development of salt marshes - at high marsh elevations, interspecific plant community structure becomes a major driving force

the intermittent upwelling hypothesis

- propagules and food only reach shore during relaxation events - relaxation events (when upwelling stops, brings warm water to areas it does not reach during upwelling) brings more food --> prey population grows --> predator populations grows and exerts top-down control - both strong, persistent upwelling and persistent downwelling seem ineffective in replenishing rocky intertidal areas - Menge & Menge propose hump-shaped relationship where rates of ecological processes highest with intermediate upwelling - suggests that when switches between upwelling and downwelling are too frequent there is not enough food and recruits get to the coast

pinnacles of biodiversity on Earth

- rainforests, deep sea, coral reefs - coral reefs have smallest area only 0.2% of the surface of Earth - coral reefs have ~100,000 known species on Earth - CRs have ~1-5 million total (known + unknown) species - most species and biomass live within the reef in bioeroded holes

snail transplants

- recent research into the formation of these snail fronts indicate that snail grazing alone did not initiate salt-marsh die-off; instead suggests that following drought-induced dieback in distinct, yet extensive areas, allow for snail fronts to form on the disturbance edges and propagate through the landscape to cause cascading vegetation loss - synergistic effects of both bottom-up and top-down forces are causing the massive die-offs in southern marshes

local decline of corals: overfishing

- reduction in fish abundance, density, and diversity - removing herbivores triggers trophic cascade--shifts balance in favor of algae - sometimes use dynamite to stun or kill fish: this damages the physical structure of the coral

direct effects: change in abundance and biomass

- reduction in the abundance of target species & bycatch species - "fishing down" of accumulated biomass = major manipulation - strategy to move populations away from carrying capacity: desired because population growth rate is higher at low to medium abundance - maximum sustainable yield (MSY): obtained at a low to intermediate population biomass (~30-50% of biomass prior to fishing)

seagrass communities

- relatively resistant to grazing - consumed mostly by large vertebrates - large vertebrate herbivores are relatively uncommon in seagrasses - understanding seagrass ecosystems and predicting stress responses is increasingly urgent due to their steep decline in recent decades

socioeconomic consideration in marine restoration

- restoration projects quickly lose support when relocation of property owners becomes an objective - reactions to natural/ecological disasters is usually engineering-first - an engineering approach to natural disaster prevention can result in: increased erosion around building site, loss of nutrient regulation, reduced foraging and nursery habitats - this reactionary approach to disaster prevention can be avoided if conservation and sustainability become the objective for any restoration initiatives

what is restoration?

- returning a system to a close approximation of its condition prior to disturbance, with both the structure and function of the system recreated - goals of restoration based on the historical context - manipulation of populations or habitats for the primary purpose of increasing human exploitation is not restoration

vent habitats

- right above seafloor is cold, dense, oxygen-rich seawater: chimneys are physical habitat where organisms live at 40-80C - underneath the seafloor are hydrothermal fluids: nothing lives here because temp over 400C - primary producers: microbes called "chemolithoautotrophs" used energy from H2S - herbivores: grazers and suspension feeders - predators: mobile species like crabs, octopods, fish, sea stars - foundation species: usually have symbiosis with microbes (polychaetes, tubeworms, clams, shrimps, amphipods)

other consequences of climate change

- rising sea level and declining sea ice threatens coastal, benthic, and arctic communities - changing salinity because of more evaporation - due to spatial differences in temperature increase, gradients that drive storms become more intense - stronger upwelling - warmer water holds less oxygen; also can be a result of upwelling

spatial variation

- salt marsh plants survive best in freshwater or low salinity

effects of scale in manipulative experiments: scale within a single site

- scale effects the outcome of field experiments - field experiments involve small experimental units - algal canopies dominate sheltered shores; mussel bed and barnacles dominate more wave-exposed shores

patterns of species diversity

- scleractinian corals (stony corals) contribute little to reef diversity - molluscs, fishes, arthropods are mostly comprised of small, cryptic species - diversity dominated by small, cryptic, and rare species - the coral triangle: identified high-diversity reef sites based on corals, fishes, snails, and lobsters - the diversity of the region is the best predictor of diversity at a specific site - diverse tropical regions lay farther to the west and are correlated with tectonic activity

Paper: Historical Comparison of Fish Community Structure in Lower Chesapeake Bay Seagrass Habitats

- seagrass density and abundance has been chaotic between the historical and contemporary study, with more recently a dramatic decline in abundance - the analysis illustrates a change in seagrass fish community between the two study periods: a decline in species richness, an overall change in the finfish assemblage within seagrass habitats (increased presence of warm-water species), differences in abundance among key seagrass species, and inconsistencies in the pattern of relative abundance across months among the two time periods

seagrass management and restoration

- seagrass species are at elevated risk of extinction, including 3 species now considered endangered - major increases in the number of marine protected areas that include seagrasses - seagrass indicators are used to assess the quality of ecosystems in many national policies aiming to improve the health of marine ecosystems - common strategy worldwide to halt the loss of seagrass habitats is the process of seagrass restoration, in which seagrasses are planted, via transplants or seeds, to restore a degraded habitat

ocean acidification effects on seagrass communities

- seagrasses are actually expected to benefit from increases in water column CO2 levels because they can be limited by carbon - there is hope that seagrasses may help alleviate the stress of acidification for associated calcifying organisms

bottom-up control in seagrass communities

- seagrasses universally have high light requirements (11% of surface irradiance) - unlike most vascular plants, seagrasses can take up nutrients from both their leaves and roots - sediment nutrient enrichment has positive overall effects on aboveground and below-ground biomass, whereas water column nutrient enrichment has negative effects on these responses - the roots and rhizomes of seagrasses are often situated in anoxic sediments containing high levels of toxic metabolites, esp. H2S - providing oxygen to their below ground tissues carries a large energetic toll and possibly explains why the minimum light requirements for seagrasses are much higher than those of micro and macroalgae

local decline of corals: poor water quality

- sediment, nutrients, and pollutants runoff from areas developed by humans - eutrophication linked to prevalence and severity of coral diseases - fish abundance is 60% lower in polluted areas compared to pristine areas

indirect effects of degradation

- sedimentation on rocky coastlines increased sediment-tolerant turf algae that provided habitat for invertebrates and sea cucumbers - coral declines from bleaching, storms, or over-predation by sea stars leads to a shift to macroalgae communities which slow or stop coral recovery - fishing in NE increased herbivorous crab populations, decimating the foundation species, cordgrass, by 40-90%

population-level approaches: create spawning sanctuaries

- setting aside no-take areas for species of interest to reduce juvenile mortality - protects habitat by reducing harvest and has the potential to increase disease resistance - blue crab spawning sanctuary in the Chesapeake

dimensions of expansion

- spatial expansion and intensification (coastal and estuarine --> continental shelves --> open ocean and deep sea) - continual rise of fishing effort, global CPUE decline - increasing concern because CPUE decline is a proxy for declining fish abundance - newly exploited species allow increase in the fraction of marine biodiversity used for human purposes

the "biological pump" solution

- the oceans naturally remove CO2 from the atmosphere via diffusion and that CO2 is taken up by phytoplankton via photosynthesis - when phytoplankton die they sink to the seafloor where CO2 is effectively transferred from atmosphere to seafloor - these processes remove roughly 1/4 of anthropogenic carbon emissions from the atmosphere - enhancing pump by fertilizing the surface of the ocean with iron fillings to spur plankton blooms - problems: only a small fraction of phytoplankton sink to the seafloor; very inefficient

zoantheria (hexacorallia): order scleractinia

- stony corals - diverse and abundant (often solitary) Cnidarian "corals" and many reef-building aggregations of other organisms in the Paleozoic - the order scleractinia diversified in the early mesozoic (triassic) - probably acquired symbiotic algae (dinoflagellates) by the mid-late mesozoic or before, giving rise to widespread continent-modifying coral reefs in the mid-late mesozoic - rudist bivalves also were dominant reef builders during the late mesozoic - rudist reefs hundreds meters deep, ran for hundreds of kilometers on continental shelves - at one time, fringed the N. American coast from the Gulf of Mexico to present day NE - paleozoic corals were mostly solitary; today, both solitary (deep or cold environments) and colonial (tropical shallow reefs) - relatively few solitary species remain, the few remaining have very large polyps - polyps secrete calcareous skeleton (calcification = growth) - CaCO3 deposited within mesenteries/septa = sclerosepta - sclerosepta form a cup-like "calyx" or "corallium" - gastrovascular cavities of neighboring polyps are connected: colony can share food - growth (i.e. calcification) is facilitated by intracellular symbiotic dinoflagellates

grazer control

- strong role that grazers and top-down forces play in regulating marsh population - goes against Odum doctrine which states that bottom-up control of marsh ecosystems through nutrients, temperature, anoxia, and salinity are the only important processes occurring

consequences of seagrass genetic structure

- studies have found that higher allelic diversity increased vegetative shoot production and sexual reproduction in transplanted seagrasses - increased genetic diversity can be important in the buffering of seagrasses against multiple perturbations

effects of other habitat-degrading activities

- substantial increase in sedimentation and a related increase in turbidity from human activities - sedimentation on rocky substrates can prevent the settlement of larvae of hard-substrate organisms - increased mortality of adults by smothering foundation species thereby affecting any associated species - sedimentation removes late-successional, large-bodied, and long-lived species which are then replaced by opportunistic flora and fauna - kelp forests, mangroves, and seagrasses can control sedimentation, but for the most part sedimentation controls community composition and structure - steamships have been dumping burnt pieces of coal, called clinker, into deep water which makes up 50% of the hard substrate available for attachment by brachiopods across large areas of the abyssal plain

Paper: Epifaunal community structure in chemically different hydrothermal vent habitats

- sulfide concentrations were different between the two sites - site with higher concentration of H2S had higher species diversity and tubeworm biomass - tubeworm biomass correlated with higher biodiversity - community structure was not significantly different between the sites

Menge and Sutherland model

- synthesized previous experiments to create model comparing importance of stress, disturbance, and recruitment on assemblages of rocky intertidal systems - model focused on top-down control of community structure by consumers - research today recognizes that both top-down and bottom-up processes are influenced by environmental factors and recruitment

role of temperature in bottom-up control

- temperature can influence light limitation (high temp = high respiration rates = faster plant growth) - temperature can affect the rate of nutrient uptake; optimal temperatures for nutrient uptake are not necessarily identical to those for photosynthesis and growth - warmer temps tip the balance of grazing vs. production toward a stronger top-down control on algae

habitat-level approaches: coral reefs

- temperature rise and ocean acidification - restoration attempts for coral reefs are especially time sensitive - restoration of coral reefs after disturbance events is especially labor intensive: rectifying overturned corals, removal of sediment coverage - characterized by transplant - first step in restoration: restore vertical relief - establishment of diverse reef habitat can take decades - conservation efforts are often much more cost effective than restoration

biodiversity

- terrestrial plants show species richness enhances ecosystem functions through primary production and nutrient cycling - typical of early stages of marshes, but in later years, ecosystem functioning relies on species identity over richness

communities around hydrovents

- the areas around hydrovents are biologically more productive, containing complex communities fueled by dissolved chemicals - the mixing of vent and ambient fluid causes coexistence of hydrogen and oxygen that doesn't usually occur; this provides energy for microbial production called chemosynthesis

non-consumptive predator effects and trait-mediated indirect interactions

- the central idea is that the presence of one species modifies a trait of a second species with a third species - NCE: non-consumptive effect - TMII: a trait-mediated indirect effect or interaction - predators have a positive effect on producing by relaxing grazing pressure

habitat destruction

- the marshes that remain are threatened by invasive species, large scale oiling, run-away consumer effects, eutrophication, global warming, drought, and sea-level rise

top-down control in seagrass communities

- the mutualism between mesograzers and seagrasses is context dependent: the outcome is sensitive to environmental conditions and to the species composition an structure of the food web, and the relationship can turn antagonistic - some mesograzer taxa feed on seagrasses even when there are alternative food sources available - studies have found a negative effect on algal blooms and positive effect on seagrasses

measuring management effectiveness

- the ocean health index (OHI) assesses the benefits of healthy oceans, with explicit focus on humans as part of coastal and marine ecosystems - an OHI score was calculated for every coastal country in the world; highest scoring country is Germany and uninhabited Jarvish Islands in the Pacific - OHI can be used as a retrospective tool to assess the effectiveness of past management actions or as a forward-looking tool to examine how future policy option may affect multiple dimensions of ocean health

spatial variation in ecological production of coastal landscapes

- valuation of the value of how an ecosystem service varies across an ecological landscape is rare - studies of coastal systems indicate that it is possible to track how ecological functions that underlie some ecosystem services vary spatially - mangrove forests and salt marshes both influence abundance, growth, structure of fish and invertebrate populations

trophic cascades in seagrass ecosystems

- the potentially strong effects (positive and negative) of mesograzers on seagrasses highlight the importance of factors controlling their abundance which leads up the food - extending mutualistic mesograzer model by connecting it to higher trophic levels, by proposing that the present lack of grazer control of algal biomass in many seagrass ecosystems is due to a trophic cascade caused by overfishing of large coastal fish predators worldwide - overfishing of top predators should lead to a cascading effect in which mesopredators increase and in turn decrease the abundance of mesograzers that consume algae, thereby releasing epiphytic algae from grazer control

what is "reef growth"?

- the rate of rise of cemented reef basement - corals then can settle on top of the basement 1. reef growth must be sufficient to keep corals near the lighted surface despite: (a) land/island subsidence and (b) sea level rise

indirect ecosystem effects

- the removal of high trophic-level predators through fishing initiates trophic cascades (2+ trophic levels) eventually altering community and habitat structure - effects of apex predators on mesopredators often powerful - "trophic triangles" can shift the roles of predator and prey - the importance of apex predator removal in pelagic, open-ocean habitats, which cover 2/3 of the planet, is more uncertain - low trophic level foragers constitute 30% of global fishery production, while also channeling photosynthetic energy from plankton to higher trophic levels - changes in biomass, species composition, and diversity loss make ecosystems more vulnerable to external processes - loss of "response diversity" lessens communities' ability to adapt - overall decline in ecosystem production and services - through MPAs, all this is (partially) reversible

reproduction and dispersal of seagrass

- there is a better understanding of vegetative processes not sexual reproduction - there are high levels of genetic diversity which indicate that sexual reproduction and dispersal may be more prevalent

phylum cnidaria: scyphozoa and cubozoa

- these are sometimes grouped and called "medusazoa" - very reduced (or no) polyp, only medusa - characteristic traits of this clade: (1) septate gastrovascular cavity, (2) gonads to gastrovascular cavity in medusa, (3) reduction of polyp

population-level approaches: habitat conservation and restoration

- this approach is used when the bottleneck to the population is post-settlement mortality - hard to protect international waters

the mutualistic mesograzer model

- this model proposes that the dominance of seagrasses in temperate systems is facilitated by small herbivorous invertebrates, notably amphipod and isopod crustaceans and gastropod molluscs, collectively referred to as mesograzers - suggests that productivity and even the existence of some seagrass ecosystems depends on facilitation by mesograzers

Paper: Greenhouse Gas Fluxes from Salt Marshes Exposed to Chronic Nutrient Enrichment

- though both marshes have global cooling potential (ability to store greenhouse gases), when the marshes are fertilized, the study shows that there is a large flux in N2O if nitrogen is in large supply with phosphorus - they believe the N2O fluxes will vary depending on the source of the nutrients and the type of marsh that is being contaminated - this experiment does show that eutrophication increases the release of greenhouse gases from salt marshes and the release of N2O reduces the value of the salt marsh as a blue carbon sink

adaptation and acclimatization

- tolerances for abiotic change vary within species: interpreted as evidence of genetic potential for population persistence despite changing environmental conditions via organisms' physiological plasticity or genetic variation that can enable natural selection - coccolithophore populations exposed to elevated CO2 grew and calcified faster than control populations when both populations were subsequently exposed to acidified conditions - existence of standing variation in thermal tolerance within a population suggests that natural selection drives thermal adaptation - corals display among-clone and among-population variation for thermal sensitivity and are able to physiologically acclimatize to natural and experimental warming * key question: which (if any) taxa will adapt or acclimatize fast enough to keep up with abiotic conditions?

grazer diversity and trophic processes

- top-down control should be stronger in more diverse consumer assemblages - diverse grazer assemblages better resist establishment of newly introduced invaders and maintain a low and stable algal biomass in the face of experimentally induced warming, nutrient loading, and pulses of freshwater runoff

cerianthidea

- tube anemones - live and can withdraw into tubes in soft sediment, leathery tube is secreted from fibrous material similar to nematocyst threads - lack paired mesenteries - outer whirl of pointed tentacles, inner whirl of shorter tentacles used for food manipulation - often live in deep environments

subsidies from seagrass to other habitats

- two pathways by which seagrass production is transferred to other ecosystems: (1) passive export of seagrass detritus and dissolved organic matter; (2) active transport of seagrass-derived biomass in the form of mobile organisms - seagrasses also link other habitats through non-trophic mechanisms by providing safe corridors through which organisms can move between habitats

habitat-level approaches: oyster reefs

- unlike salt marshes and seagrasses, oyster reefs are exploited as a fishery - they have a large impact on nutrient availability - can facilitate vegetation - they have faced a century long period of over-harvesting - recruitment favors settlement on the shells of other bivalves - over-harvesting of oysters therefore causes a decrease in recruitment - majority of restoration efforts have focused on improving the fishery - few studies have tracked long-term fate of restoration efforts

using comparative experimental approach

- used to examine oceanographic processes over large scales - focuses on recruitment rates, colonization, and growth of major space holders (barnacles + mussels), predation, and competition - colonization and succession measured by clearing an area and watching recovery - recruitment recorded monthly - tests "upwelling hypothesis": large-scale upwelling intensity drives benthic processes - both showed compelling evidence for link between oceanographic and benthic processes

quantifying ecosystem services

- valuing ecosystem services: quantifies the benefits in terms of human welfare that ecosystem services provide - economic valuation: measures gains or losses in human welfare from changes in ecosystem services caused by human impacts - human drivers of ecosystem change --> ecosystem structure and function --> ecosystem goods and services --> values --> back to human drivers

recruitment variation and community dynamics of intertidal rocky shores

- variation in settlement and recruitment determine order of importance of predation, grazing, and competition - may be caused by spatial, temporal variation in propagule supply from water column to shore; also influenced by postsettlement mortality - "supply-side ecology" became major focus of marine ecology: analyzes importance of variation

impacts of hydrovent mining

- vents are in fact resilient enough to withstand mining based on the claim that there is a quick relocalization of the community after an eruption - mining leaves behind rubble and the substrate change could alter how quickly a destroyed vent could be recolonized by vent species

physical and chemical effects of climate change

- warming: infrared radiation is reflected back to the surface - acidification: CO2 is dissolved in the oceans to form H2CO3 - sea level rise and ice loss - salinity - winds and upwelling - reduced oxygen

global decline of corals: increased CO2 concentrations

- warming: rise of 0.74 degrees C in sea surface temperature - temperatures of 1-2 degrees C above seasonal maximum triggers bleaching - acidification: carbonic acid H2CO3 inhibits corals from creating and maintaining skeletons

habitat restoration

- wherever prevention of degradation is not feasible, restoration can reverse some damaging trends - working with ecological feedback loops, trophic cascades, and environmental disturbances can help restoration efforts succeed

valuation of coral reef benefits

- widespread loss of coral reefs prompted investigations into benefits they provide - support for nearshore fisheries, supply aquarium trade, provide valuable shoreline protection, recreational benefits, buffer shorelines from severe weather - reef ecosystem services function better with connectivity between other reefs, mangrove forests, seagrass beds, etc.

fishing methods

1. "fixed gear": remain in place while fishing; fish trap, net, hook-and-line methods, wire fish traps, bottom longlines, gill nets 2. "mobile gear": dragged over the sea floor or through the water column; bottom trawls, mid-water trawls, dredges 3. pelagic (open-ocean): target either schooling foraging fish, squid, and top predators; drift nets, seines, pelagic longlines

class anthozoa: four subclasses

1. alcyonaria (octocorallia): soft corals and gorgonians 2. cerianthidea: tube anemones 3. antipatharia: thorny or black corals 4. zoantheria (hexacorallia): anemones, stony corals

importance of bioeroders

1. all facilitate the development of complex 3D reef structure--responsible for high reef diversity 2. destroy reef substrate, cause corals to dislodge (esp. in storms) --> death 3. produce sand, sediment, some of which is cemented --> affects reef growth ***know how/when each evolved

why quantify ecosystem services?

1. assessing trade-offs 2. evaluating cumulative impacts 3. measuring management effectiveness

what happens when symbiosis breaks down? external causes

1. excessive temperature: this is why there is concern about global warming (corals already live at near the upper end of their temperature tolerance) 2. UV: volcanoes erupt, particles in stratosphere serve as nuclei for break down of ozone, or extra low tides in El Niño 3. Pollution: high organic material in water, bacterial action = low O2 4. Low light: volcanoes; soot clouds from burning oil wells during Persian Gulf War in the Middle East

how do corals feed?

1. feed on zooplankton using nematocysts on tentacles 2. symbiotic zooxanthellae: only in reef-building corals; dinoflagellates live inside coral cells, lose flagellae, may either invade from outside seawater or be passed on in egg; accelerate CaCO3 production (10X); provide organic molecules (carbs, amino acids) 3. mucous and ciliary entrapment of detritus (filter feeding) 4. direct absorption of organic molecules through epidermis

how do corals benefit?

1. gets photosynthetic products (carbs, amino acids) for food 2. can grow faster (lay down CaCO3 10x faster)--critical for competition for space

challenges to linking ecosystem services to action

1. many people are skeptical of model-based results 2. developing rules of thumb that describe ecosystem provision shifts are important in order to guide societal decisions about how to manage different marine ecosystem services 3. need to assess whether managing with an ecosystem lens has improved outcomes 4. some people do not see the value of quantifying nature's benefits as "services"

how is coral skeleton destroyed and what is the significance of this?

1. micro-borers or micro-bioeroders 2. macro-borers = internal bioeroders 3. scrapers, macro-bioeroders, external bioeroders

how does zooxanthellae benefit?

1. protection from predators (herbivores) grazing on phytoplankton up in the water column 2. abundant source of N from host's metabolism

two major ecological types in early Paleozoic seas

1. sessile filter feeders: sponges, early corals, hydroids, brachiopods, bryozoans, early bivalves, early echinoderms 2. predators-scavengers: arthropods, worms, echinoderms, molluscs, early chordates

types of effects fisheries have on marine communities

a. direct effects on targeted fish populations b. collateral damage to bycatch species c. transformation and destruction of bottom habitats d. indirect effects - alter abundance, biomass, age, and size structure - affect species composition and diversity - selective removal of certain species and size classes - changes amplified by species interactions