oceans exam 3

Aphotic Zones

Food Sources Particulate detritus raining out from above. Sinking carcasses of large animals. Prey from the aphotic and photic zones

Seasonal Cycles and species succession

Herbivore and carnivore life cycles are sequenced to match phytoplankton or zooplankton food source availabilities. If the phytoplankton species succession is disrupted - impacts felt by other species in the food chain

marine ecosystems

Kelp forests Rocky intertidal communities Sargasso Sea Polar regions Deep, dark ocean waters below the pycnocline Hydrothermal vents Coral reefs Salt marshes Seagrass Beds Estuarine Mangroves

Phosphorous Cycle

Recycled Efficiently by the microbial loop. Not usually limiting. Biological form of phosphorous: Phosphate (PO43-)

Tropical regions

Relatively uniform, high light intensity year-round. Nutrients limit PP which is low (except upwelling regions). Little seasonality of phytoplankton growth. Permanent thermocline below shallow mixed layer. Deep photic zone.

Coastal Zone Variables

Salinity Depth Temperature Waves and Tides Turbidity and Photic Zone Currents- dominated by local winds and tides, interact with shoreline Nutrients (more info ch. 13 slide 4) Estuaries - shallower, more influence from rivers/land, tides compared to coastal ocean - the above properties differ accordingly.

Pelagic Suspension Feeding

Salps are a great example of pelagic suspension feeders. The body of a salp is basically a barrel covered in mucus. Salps live together in a colony, which forces water to flow through the individuals in a current. The current of water flow allows them to filter feed from the passing water. Each individual is more likely to find food with the colony working together to move through the water column.

Estuaries

They can be classified on the basis of their geological origin: coastal plain, bar-built, tectonic estuaries, fjords Estuaries are partially enclosed body of water where freshwater from rivers mix with oceanic salt water. can be classified based on their geological characteristics

Chemosynthesis

carried out by phytoplankton, bacteria, and cyanobacteria §chemosynthetic communities typically occur in extreme environments (deep ocean, anoxic waters, no light) Energy to synthesize organic matter is obtained from: - oxidation of hydrogen sulfide to sulfate - transformation of metals (Mn, Fe) from a reduced to an oxidized form - oxidation of hydrogen to water - oxidation of methane to carbon dioxide and water

Prokaryote

generally microscopic, single-celled organism that have no membrane bound nucleus or internal structure Domain Bacteria: single cell, no organelles, have carbohydrate based cell wall archaea: diferrent cell wall, organic compounds, and different genes (some single celled, others not) live in extreme environments

diatoms

have a siliceous frustule (hard external "shell"), are among the largest phytoplankton and are desirable as food for larger zooplankton and small herbivorous fishes. -require Si as a nutrient to form their shells. dominant species on the coast and shelf

Turbidity

measure of suspended solids in a liquid, obscures light penetration caused by particles (suspended sediments, phytoplankton, and other organic materials) •Limits light penetration, photosynthesis Nutrients are also delivered with particles - so there is a balance between too little and too much terrestrial input. Turbidity varies on a gradient from inshore out to the outer shelf.

Estuary

partially enclosed body of water where freshwater from rivers mix with oceanic salt water

Coastlines are formed/modified when:

sea level rises or landmass subsides landmasses are added to or removed -erosion/deposition

Hunting and Defense

speed, lures, camouflage, concealment, spines and armor, poisons, group cooperation slide 27 ch. 14

Community

the organisms that coexist in a given location multi-species multiple scales

Taxonomy

§All living things are arranged into formal groups according to their anatomy, physiology, and genetic differences. §"tree of life," all species are classified into 1 of 3 domains: §Bacteria §Archaea §Eukarya §Representatives of every domain and kingdom of life can be found in the ocean.

Iron (Fe) as micronutrient

§All phytoplankton require Fe for photosynthesis. §Cyanobacteria require high amounts of Fe to convert N2 to biologically usable forms (NH4+, NO3-, NO2-) §Often a limiting nutrient for phytoplankton.

benthic layers

intertidal sublittoral bathyal abyssa hadal

rapid and slow

•Tectonic processes (>106 year time scales) slow but constant, modify coasts at boundaries and hot spots. •Volcanic eruptions in magmatic arcs at convergent plate boundaries, can create island chains (Hawai'i). •Coastline can be created or destroyed by earthquakes, that raise/lower sections of the land and seafloor. •Divergent continental margins can create seas/oceans. •Landslides occur often on volcanic islands (e.g., Hawaii) with steep underwater flanks •A section breaks loose, slides down to the deep-ocean floor destroying the old coast and creating a new one •Relatively "Common" occurrence in volcanic island history. Landslides can destroy large sections of island and their inhabitants AND cause tsunamis •Hawaiian slides could impact the West Coast with tsunami waves > 10 m high •Large Hawaiian slides occur every 100,000 years (or more); every 10,000 years world wide •Island of La Palma, Canary Islands is thought to be close to a collapse that could impact the US East Coast Glaciers • melting over last 15,000 years, since last Ice age • glaciers cut narrow, steep valleys as they retreat creating fjords • fjords are characterized by submerged sills • made of glacially deposited sediments and rock (aka moraines). River-borne sediments e.g., Mississippi River Delta § Coasts are formed/modified as rivers deposit sediments. § Most rivers flow across a gradually sloping coastal plain before reaching the sea. § rivers slow down, sediments fall out in this flatter area. àforms a delta (after the valley fills in) • delta soils - rich in nutrients, organics à great for agriculture • easily flooded and subject to drastic modifications to river courses à not great for human civilization • levees control flooding but reduce soil quality Waves •Breaking waves are the principal coast-modifying process. •On rocky coasts, breaking waves progressively erode the rock away. •Soft, sedimentary rocks erode much faster than hard, volcanic rocks. •Erosion is faster on coasts that are exposed to high wave action. •**Exacerbated by wind, weather events. •On an indented coastline, erosion occurs fastest at headlands •Sand (formed via erosion) accumulates within the intervening bays •Preferential erosion of headlands straightens the coast over time (removing the headlands) •New Jersey- former headlands along the northern shore have been eroded, moving sand downshore •On rocky coasts, waves cut away rock between the high and low tide lines •land becomes unstable and breaks away, leaving cliffs •Rock erodes at different rates •As waves cut into coastal cliffs and headlands, they preferentially erode soft, less resistant rocks. •Harder rocks persist and sea caves form at the base of cliffs §Sea caves in headlands can continue to be eroded until they meet, resulting in the formation of a sea arch §As the headland erodes further the arches collapse and the remaining pinnacles of rocks are called stacks (which also eventually erode away) Niue Sea Caves•small island in the South Pacific ,world's largest coral island (coral atoll) Tide Range •Tidal currents themselves are not major agents of erosion but are factors in the severity of observed impacts. •Tidal range determines the height range over which wave erosion occurs- and the width of the shore •Large tidal range spreads wave energy over a large vertical range §Coasts with small tidal range erode faster because of concentrated wave energy Tides and Waves •Wave erosion, combined with boring and dissolution by marine organisms, undercut this rocky coastline on the islands of Palau in the Pacific Ocean. •Erosion is confined to a very narrow height range because the tidal range is nearly zero Vegetation •Vegetation impacts rate at which coast forming and modifying processes operate. •The type and extent of vegetation on the coast affects the rate at which winds, streams, and storm waves erode the land. •Grasses are particularly important in protecting sand dunes from erosion •Rooted plants (sea grasses, salt marsh plants, mangroves) that grow in the water help prevent erosion by waves and currents plants dissipate wave energy that would otherwise erode land •Tree roots (on land) and animal activities such as burrowing, contribute to continuous erosion of rocks and soils Biological Processes Uplifted and eroded coral reef forms a jagged shore often called ironshore •Reef-building corals must be underwater •Reefs protect coastlines by absorbing energy from ocean waves Issues threatening coral reefs: warming waters, eutrophication, and ocean acidification •Many reefs are located around islands or submerged pinnacles that are sinking isostatically •Isostatic sinking, sea-level rise increase water depth -- decreasing the amount of light reaching the corals for photosynthesis •Coral reef growth is expected to decline as the ocean becomes more acidic due to dissolution of calcium carbonate.

Harmful Algal Blooms (HABs)

- Excess nutrients and long water residence times combined with insufficient predators - Harmful algal blooms! - Some dinoflagellates produce harmful toxins that are harmful as they go up the food chain. - Also lead to high bacterial respiration and anoxia or hypoxia - Fish kills, "dead zones" When HABs and zooplankton die-off, they are consumed by decomposers (bacteria, fungi). The decomposers use dissolved oxygen. When dissolved oxygen depletes - Animal die-offs. Dead zones in the Gulf of Mexico, also Chesapeake Bay Dead zone size varies year to year. Typically greatest in the summer after spring blooms and when water temps are warmer (gases are less soluble).

Coastal Ocean

- the region between the land and the open ocean that is dominated by processes resulting from land-ocean boundary interactions. Includes the continental shelf, part of slope.

Eutrophication and Seagrass

-Also implicated in coral reef, seagrass die-offs. -Macroalgae, turbidity shade reefs, seagrass.

Sargasso Sea Biology

-Home to a diverse community of fish, invertebrates (>100 sp.). - -At least 10 species are endemic (found nowhere else) to Sargasso Sea - including crabs, shrimp, anglerfish. - -Feeding grounds for tuna, marlin, swordfish, sharks. - -Breeding grounds for eels, marlin. - -Stopover site for humpack whales, nursery habitat for turtles, other species.

Coccolithophores:

-Smaller, less abundant than diatoms or dinoflagellates -more abundant in ocean than coastally -have a mosaic of calcareous plates covering the cell wall (need Ca2+ and CO32-) -think about coccoliths in terms of ocean acidification. Species are not evenly distributed through out the oceans. §Different species dominate based on nutrient requirements and availability ¨Coccoliths are most abundant offshore because their nutrient requirements are not as high as Diatoms and Dinoflagellates

Hydrothermal Vents

-hotspots of diversity near the emanation of hydrothermal fluids -chemosynthetic food web base Seawater seeps into cracks in the seafloor. Oxygen, potassium, calcium, sulfate, and magnesiuim are removed from seawater. Hydrothermal fluids dissolve copper, zinc, iron, hydrogen sulfide, and hydrogen as they move through the basalt and reach highest temperatures. The fluids rise up through the crust carrying dissolved metals. Upon reaching the seawaters, the fluids mix with cold, O2-rich water. The metals and sulfur form black metal-sulfides. Microbes conduct chemosynthesis on the Fe, S, hydrogen. Black smokers -hot water (270-380 °C), high flow rates Most common (as far as we know) Associated with ocean ridges Very low pH (~3) No O2, nitrate; high H2S, sulfur-containing minerals, Fe, Mn White smokers (250-300 °C) aka 'warm vents' More Barium, Calcium, Silicon than black smokers Diffuse Flow - clear, low T (~ ambient seawater) further away from ridge.

Dinoflagellates:

-smaller than diatoms, weakly motile -many have a readily decomposed cellulose cell wall but none have hard parts. -They tend to dominate the phytoplankton when silica concentration is too low for diatom growth. -more abundant in open ocean than coast or shelf not always autotrophs

2 types of coasts

1. Erosional coasts- net loss of land - eroded by wave action, river or glacier-induced erosion e.g., cliffs, rocky shores 2. Depositional coasts-net accumulation of land - sediment accumulation after being transported to the area in rivers and glaciers or by ocean currents and waves e.g., deltas, mangroves, salt marshes, barrier islands, sand dunes

Environmental Requirements for Coral Reef Formation

1.Underwater (below low tide zone). 2.Water temperatures >18°C. 3.Need light (most reefs < 25 m depth) for zooxanthellae 1º production. 4.Low turbidity - for light & bc high [particle] can smother corals. Relatively stable salinity Typically found near continental margins and islands. (Why?)

coral news

11 billion items of plastic found on 1/3 of coral reefs in Asian Pacific bleaching attributed to warming, El niño - parrotfish have teeth made of super strong fluoroapatite crystals that may be useful for building strain-resistant electronics, etc

Emerging Contaminants

>2700 compounds according to the EU JRC Investigated for persistence, toxicity, bioaccumulation potential Pharmaceuticals (e.g., opioids, ibuprofen, tramadol, tamoxifen, clotrimazole....) Personal Care Products (sunscreen, benzophenone, fragrances) Endocrine Disrupting Compounds (estrogens, progestogens, testosterone)

Estuarine Circulation

Additional factors affecting fresh and seawater mixing: wind-driven wave mixing shape and depth of the estuary friction between the moving freshwater and seawater layers friction between the water and seafloor the Coriolis effect

Contaminants: Metals

Al (mineral component, mining byproduct), As (pesticides, herbicides, wood preservatives), Cd (alloys, batteries, pigments), Cr (alloys, catalysts, pigments), Cu (wiring, electronics, plumbing), Pb (gas, mining, batteries, pigments, paint), Hg (electronics, mining), Ni (alloys, batteries), Se (electronics, glass, pigments), Zn (alloys, catalysts) •Impacts are greatest near sources •Industrial factories and recycling plants •Mining sites •Fossil fuel burning (coal, oil) •Accumulate in sediments •Can produce sublethal to lethal effects in organisms •Decrease biodiversity

Coasts, Coastal Ocean, Estuaries

All 3 are operationally defined. •Coast - from where the water meets the land inland to where there is no longer ocean influence on land. • •Coastal ocean - the region between the land and the open ocean that is dominated by processes resulting from land-ocean boundary interactions. Includes the continental shelf, part of slope. • •Estuary - partially enclosed body of water where freshwater from rivers mix with oceanic salt water.

Mobility

Anemone hermit crab: Young hermit crabs will often pick up a young sea anemone to attach to their shell and they become partners for life. They even grow at roughly the same rate. When hermit crabs outgrow their shell, they often take the sea anemone with them to the new one. Some sea anemones have gone so far as to cover most of the surface of the hermit crab's shell so when the crab eventually outgrows the shell, he doesn't have to move. Mobility allows for a much larger forage area for the anemone. The anemone protects the crab with stinging tentacles.

Mutualism

Anemonefish benefits: hide from predators, lay eggs in anemone tentacles to avoid predators so they don't need as many eggs, can eat the anemone mucus, food scraps, or the anemone tentacles, possibly the anemone tentacles sting and remove external parasites Anemone benefits: cleared of dead tissue, mucus, food wastes, and external parasites, protection from predators by the anemonefish, freedom to remain open when the fish fights off predators means they can feed more with more time open, sometimes the anemonefish feeds the anemone

well mixed

At low freshwater flux and/or strong wind mixing freshwater can be completely mixed with ocean water Vertical mixing is intense, very strong tidal currents. No halocline. Salinity ↑ progressively with distance down the estuary. Water has higher salinity on right side* due to Coriolis deflection. (*N. hemisphere) There is a net residual current (current left after tidal motions are averaged out) across the estuary.

Toxicity

At some level of exposure, contaminants become toxic. Toxic effects: Necrosis (lesions) Inflammation Cause genetic damage Cause cancer Toxicity can be: Chronic or acute Sublethal or lethal

Major Biological Processes

Autotrophy = Photo/Chemosynthesis 6H2O + 6CO2+ energy → C6H12O6 + 6O2 (energy from sun or chemicals) Heterotrophy = Respiration C6H12O6 + 6O2 → 6H2O + 6CO2+ energy Autotrophic organisms synthesize organic matter using light or chemical energy (primary production: plants, protists, some bacteria, archaea) Heterotrophic organisms consume autotrophic production to gain energy and make more cells (secondary production: animals, fungi, some bacteria, archaea)

Bioaccumulation and Biomagnification

Bioaccumulation: the concentration of contaminant grows with exposure because it is taken up faster than it can be metabolized/excreted. Biomagnification: contaminant concentrations increase up the food chain. Primarily fat soluble substances such as PCBs, DDT and methylmercury, are biomagnified Reason to avoid eating fish high on the food chain! bioaccumulation: Effect gets more dramatic with fish age.

Distribution of Nutrients and Dissolved Oxygen

Ch. 12 slide 19 graphs §Nutrients consumed to depletion by photosynthesizers in the photic zone - then released below the thermocline via respiration and decomposition. area in yellow: mixed zone, delivering nutrients up §[Dissolved O2] is high in surface waters, decreases below the thermocline as O2 is used in respiration and decomposition. §[O2] increases with depth below the thermocline. §Deep ocean water comes from high latitude, O2-rich surface water. §Deep Pacific: higher nitrate, lower O2 concentrations than deep Atlantic. §"Younger" water forms and sinks in high latitude N. Atlantic - has higher [O2] à recent contact with atmosphere, photosynthesis. §[O2] decreases with "age" and travel time à O2 is consumed during respiration. [NO3-] increases with depth, "age". decomposers release nutrients back to the water

Hydrothermal Vent Ecosystems

Chemosynthesis (by archaea and bacteria) supports ecosystem. - - Biomass decreases w/ distance from vent. - Giant tube worms (Riftia sp.) abundant (symbiotic relationship w/ chemosynthesizers). - diverse assemblage of filter feeders and predators. Tube worms are abundant components of vent communities - dependent on a symbiotic relationship with chemosynthesizers (analogous to corals and zooxanthellae) - clams and mussels at vents also rely on microbial symbionts

Geo-physical Characteristics

Coastal oceans are shallow - water movements are affected by the seafloor and the coastline Rivers discharge freshwater into coastal waters with implications for biology, chemistry, etc. (Rivers discharge freshwater into coastal waters with implications for biology, chemistry, etc. -rivers bring nutrients for biological production. In excess they can promote eutrophication. -rivers bring suspended sediments which increases turbidity which influences the depth of the photic zone and primary production -rivers bring freshwater which influences salinity which influences biological production -rivers bring pollutants.)

Formation and Modification of Coasts

Coasts have variable characteristics can be narrow or extend inland for long distances e.g., rocky shorelines, mountainous coasts, sandy beaches Coastal characteristics typically extend for 1,000's of km Dynamic over time: continually changing on days to millennial time scales

Polar Regions

Common conditions at both Poles: Extreme variations in light seasonally. Low surface water temperatures Seasonally variable ice cover High winds promote mixing and prevent thermocline formation High nutrient abundance (*Antarctic can be iron-limited) Ice algae and Polar Primary Production (slide 30 lecture 19)

Pollution vs Contamination

Contamination: human-induced increase in concentration of some component. Pollution: human alteration of the environment has adverse effects on ocean ecosystems/resources. Assimilative capacity: maximum contamination load above which contamination becomes pollution. Impacted by residence time, species/ecosystem level factors. Land/ocean managerial goals: maximize societal benefits while minimizing pollution

Coral - Zooxanthellae Mutualism

Coral polyp is transparent and provides the shelter and nutrients from coral respiration. Zooxanthellae produce organic matter that the coral consumes

Factors affecting coral reef productivity

Coral reef productivity >>> than surrounding ocean The coral-zooxanthellae mutualism recycles nutrients Reef structure causes some upwelling by creating eddies in currents that flow past them--> brings nutrients partially closed systems nutrients are recycled in tight microbial loop organisms are residents - don't export resources

coral reefs (a type of marine ecosytem)

Corals are present throughout the oceans; coral reefs are not! Hermatypic corals build reefs. Grow where water temp. > 18°C (tropical waters between ~30°N and 30°S). Range extends to higher latitudes on the western side of each ocean. (Why?)

Coral Broadcast Spawners

Corals release eggs and sperm into the water column: called broadcast spawning. The eggs and sperm combine to form fertilized eggs. These fertilized eggs can then travel on the water currents, or disperse, to grow new corals in other areas with suitable habitats. This release of sperm and eggs is precisely timed on one night by the tidal cycle and moon phase. They don't have any sort of parental care, so their strategy is to just produce a ton of eggs and sperm and hope that some of them survive

Camouflage

Counterillumination Here is an example of camouflage with the hatchetfish. It produces bioluminesce at the bottom of its belly. This way, when a predator is below it looking up the hatchetfish's belly is glowing blue light just like the light downwelling from the sea surface. It makes the fish almost invisible to predators from below. Tradeoffs: it costs a lot of energy to produce your own light but it protects you from predators

Parasitism example

Cymothoa exigua: The complete life story of a tongue-biter has yet to be unraveled, but we know that they initially enter their hosts through the gills, beginning as males but changing sex as they grow older. At her first opportunity, a newly female exigua climbs into the host's mouth and attaches herself to the tongue, draining blood through her front claws until the tongue gradually atrophies and disappears. Hooking her spiny tail into the remaining stump, the vampiric isopod can now be manipulated by her host as a fully functional new tongue.

Effects of sewage on the Benthos

Degradation of the benthic environment in areas affected by sewage discharges to the marine environment. Current strategy: discharge into select areas to minimize extent of impacts.

Deposit Feeding

Deposit feeders eat food found within the sediments. A lot of detritus that falls onto the seafloor gets buried quickly. They are often concentrated in the upper layers of the sediments, where the food is most abundant. They tend to ingest the sediments and digest any organic matter in that sediment. Then they excrete any inorganic material that they cannot digest. The first pane (a) shows a goatfish who has whisker-like barbells to sense small invertebrates buried in the sediments. The heart urchin (b) eats invertebrates that it finds in the sediments as it digs around. The innkeeper worm ( c) and lugworm (d) ingest the sediments, digest any food (such as microbes) in the sediment, and then excrete the sediments back out for whatever they cannot digest.

DOC

Dissolved organic matter DOCs in seawater are very low concentrations, so few marine species are known to rely on DOCs for their main food source - such as bacteria and archea.

Mesopelagic Zone

Diurnal Migration §Copepods, flagellates, Nautilus, and other zooplankton. §Migrate to mesopelagic by day to lessen predation pressure. §Use photophores to throw off predators. §Feed at night. Have to adapt to changing pressures, maintain buoyancy Mesopelagic fish species: often odd-looking, red, have unusual adaptations. -Take advantage of meals of opportunity (unhingeable jaws, expanding stomachs) -Detect food sources in very low light environment, camouflage self (eyes, photophores) -Confuse prey, predators, detect mates (lures, photophores) Red color doesn't reflect ambient light.

Trophic Efficiency:

Eating tuna versus eating sardines (assuming 10% trophic efficiency at each trophic level §Eating sardines makes use of ocean primary production 1000 times more efficiently than eating tuna.

Sargasso Sea "Floating Ecosystem

Ecosystem in the N. Atlantic Ocean centered on large masses of Sargassum sp. drift algae maintained by physical oceanographic currents. Largest open drift algae ecosystem. (occurs in coastal ecosystems at smaller scale.)

Supralittoral ("Splash") Zone

Essentially on land. Spray delivers moisture, nutrients which support lichens and blue-green algae. Grazed by snails, limpets and isopods that are adapted to long periods of dry conditions.

Classifying Estuaries by Circulation

Estuaries are most often classified on the basis of circulation characteristics as: salt wedge partially mixed well-mixed fjord inverse estuaries *Different segments of a single estuary can exhibit different circulation characteristics. Segments may change classification based on river flow rate change (for example).

Estuarine Biology

Estuaries à challenging places for organisms to live due to variable conditions. Changes in salinity are particularly difficult since they change the osmotic pressure. Fewer species live in estuaries than in the open ocean. Estuaries generally have abundant nutrients and light à sustain high biomass. Some species of fishes migrate through the estuary as part of their life cycle: §Anadromous fishes such as salmon live most of their lives in the ocean but return to fresh water to spawn. §Catadromous fishes such as eels live most of their lives in freshwater but migrate to the oceans to spawn. # of species of marine, estuarine, and freshwater origin varies within the salinity gradient of a typical estuary Species diversity is low in the brackish water section of the estuary where the salinity stress is greatest for both freshwater and marine species

Particle and Contaminant Transport in Estuaries

Estuarine circulation tends to trap particles and their associated contaminants in the estuary. In many estuaries, an accumulations of particulate matter creates high turbidity near the landward extent of seawater intrusion. Particles transported seaward in the upper layer may sink to the lower layer before leaving the estuary and then return to the high turbidity area in the landward flowing lower layer. Many planktonic estuarine organisms use this pathway to stay within the estuary or to reach an appropriate point in the estuary at the right time in their life cycle. The maximum primary productivity because more light can penetrate that region, and nutrients are available because they are regenerated by the decomposition of suspended detritus particles transported up the estuary in the lower layer and are then mixed into the surface water at the turbidity maximum. Maximum zooplankton populations and growth occur downstream of this area to take advantage of the phytoplankton drifting seaward in the upper layer Fish production is maximum downstream of the zooplankton maximum.

2 types of Sea-Level Changes

Eustatic - changes in sea level due to changes in volume of water (thermal expansion of water, melting glaciers) or volume of the basin itself (divergent margins). - Occur relatively uniformly worldwide. Isostatic - local changes in sea level due to some other process (glacial rebound, sediment compaction)

Eutrophication in Coastal Oceans

Eutrophication and associated bottom hypoxia are serious regional stresses, but globally significant Mississippi River plume/northern Gulf of Mexico

Deep Seafloor

Even lower food supply - suspension feeding is not advantageous. Deposit feeders relatively abundant (sea cucumbers, brittle stars). Chemosensory adaptations enable some fish to detect fallen carcasses.

High Tide Zone

Extreme swings in T,S; must be protected from dehydration/desiccation Waves become a problem. Barnacles, limpets snails adapted to prolonged exposures, waves. Macroalgae (Fucus sp.) with flexible stipes and holdfasts adapted to withstand waves

Bathypelagic Zone (1000m-4000m)

Fewer prey items Brightly colored fish - unknown advantage. Use photophores to detect prey, avoid predators

overfishing

Fishing pressures above the maximum sustainable yield depletes fish populations, affects economies.

salt wedge

Freshwater runoff yields a low density surface layer that creates a stratified water column. Can extend far offshore if freshwater flow rate is high, esp. when winds blow offshore Freshwater flows seaward over seawater flowing landward. Layers separated by a strong, sharp, halocline. Lower layer water mixes upward into the freshwater layer along the estuary. Little or no freshwater mixes downward. Halocline is inclined up to the right* (looking from ocean) due to the Coriolis deflection. (*N. hemisphere!)

Benthic Suspension Feeding

Here is an example of a benthic suspension feeder: the cockle. It lives inside the sediments (infaunal) and sticks up its siphon tubes up out of the sediment. Water flows into one tube and out the other, being filtered for food inside its body. Why would an animal choose to live in the sediments and filter the water above the sediments?

Coral Reefs

Hermatypic corals' niche is defined by need for light for photosynthetic zooxanthellae symbionts. Encrusting micro- and macroalgae are important primary producers - build the calcareous hard parts of reefs Barrier Reef Separated from land by a deep lagoon Patch Reef Isolated pinnacle or mound Fringing Reef Along shoreline without intervening lagoon Atoll Ring-shaped reef, enclosing a lagoon, surrounded by open ocean

Reef Community

High biological diversity High biological productivity Fish, invertebrates Corals Gorgonians Sponges, anemones Macroalgae and turf algae (esp. if the reef is unhealthy) Zooxanthellae Phytoplankton

arctic communities

High freshwater runoff, ice exclusion produce low surface salinity and a halocline. Less mixing than the Antarctic (still very high relative to other regions). •Marine mammals at top of food chain (different species than Antarctic). •Polar bears present in the Arctic - main predators of seals. •Feeding grounds for whales (breed in tropics)

Nutrient Supply to the Coastal Photic Zone

High nutrient (N, P) inputs from land yield the highest productivity in the ocean. The most important mechanisms: coastal upwelling, turbulence (mixing), and river inputs. Rivers and runoff supply estuaries and coastal waters. Nutrients can come from natural and anthropogenic (manmade) sources.

Middle Tide Zone

High wave induced turbulence Organisms that adhere to rocks are well-suited here (mussels, barnacles, limpets) Mussels: limited at the: upper end by atmospheric exposure lower end by sea star predation snails, worms, crabs, hermit crabs, and algae live within mussel beds. Macroalgae outcompeted by mussels

Geological Origin of Estuaries

Hudson River basin-New York Harbor-Raritan Bay - complex estuary - partial characteristics of a coastal plain estuary, a fjord, and a bar built estuary in its different segments.

Watershed Characteristics Affecting Contaminant Inputs

Impervious surfaces increase runoff. - Major problem during Hurricane Harvey. Riparian buffers filter out nutrients, contaminants before they reach water bodies (tree line) Shoreline hardening (via seawalls, bulkheads, etc.) increases contaminant inputs. Natural vegetation would soak up nutrients, contaminants

Contaminant Discharge

Industrial discharge (e.g., oil refineries, chemical, pharmaceutical plants, suspended sediments eroded from burned sugar cane fields). Sewage discharge (e.g., pharmaceuticals & personal care products, organic, bacterial, & particle loads). Fuel/biomass emissions (e.g., cars, ships, wildfires, woodstoves). Pesticide/herbicide applications. Runoff.

Contaminants: Nutrients

Inorganic N (nitrate, ammonia) and Phosphate. Sources: Agriculture Air pollution Sewage Fertilizer/run-off Major impacts: Eutrophication HABs Hypoxia/Anoxia Ecosystem Alteration Excess nutrients - Algal Blooms - Increased Microbial decomposition - Hypoxia/anoxia - Fish, shellfish die-offs

•Rates of sea level rise are not uniform worldwide. Why?

Isostatic sea level changes

Kelp Life Cycle and Communities

Kelp is eaten directly by only a few species (urchins, snails, few fish) when fragmented it supports many species of detrital grazers. The kelp forest canopy provides shelter and a variety of habitats for many invertebrate and fish species. Kelp, Sea Otters, and Sea Urchins Sea urchins eat kelp sea otters eat urchins humans, killer whales, sea lions kill otters. Low otter abundance -> urchin populations expand, reduce kelp. Otters recover -> urchin populations decline, and kelp forests are slowly returning.

Antarctic Communities

Krill are an abundant food source for a variety of higher organisms. Mammals are abundant as top predators (or as filter-feeding baleen whales). Fat layers are needed for insulation for cold temps, low food conditions in summer. Krill supply food supply in summer. Fish have unique blood chemistry to adapt to cold.

Adaptations to Wave Action

Limpets, chitons and periwinkles use their foot for suction. Crabs have flattened body shape and have strong legs for gripping rocks Sea slaters are quick and live in spray zone. Quick movements to avoid waves, predators. Mussels attach via strong, byssal threads wh/ they can use for movement as well.

Kelp Forests

Macroalgal 'forests' that grow in cold (<20°C) nutrient rich (upwelling areas) waters seafloor is within the photic zone so new growth can photosynthesize require stable, preferably rocky substrates upward to the surface supported by gas-filled sacs and can form a dense canopy at the surface. Kelp obtain nutrients from the water column through the surface of its fronds Very highly productive. Kelp fronds can grow as much as ½ a meter a day.

Maternal Offloading of Pollutants

Majority of pollutants accumulate in fats. During lactation mothers transfer fat with milk. Offspring are susceptible to pollutants.

Habitats

Many species can change habitats between different life stages (ex: oysters go from pelagic larvae then settle onto a suitable substrate). Today we're going to talk about just 3 general habitats: the pelagic (water column), benthic epifaunal (on top of the seafloor sediments), and the benthic infaunal (inside the seafloor sediments). These are important definitions you should know these. •Water column - pelagic •On top of the seafloor surface - benthic epifaunal •Within the seafloor sediments - benthic infaunal

Nitrogen Cycle

More complex than Phosphorus because there are more ion transformations carried out by bacteria, cyanobacteria. Gas exchange at the ocean surface. Biological forms of nitrogen: Nitrate (N03-) Nitrite (N02-) Ammonium (NH4+) Suffice it to say that nitrogen is transformed between its many organic and inorganic forms via a variety of biotic and abiotic processes. The relative availability of various N forms can determine which bacteria, phytoplankton, etc. populate a given area.

Feeding Adaptations

Mussels, barnacles are filter feeders - allow tides to deliver food Chitons, gastropods, limpets feed using a radula (membrane with longitudinal rows of iron-containing teeth) Scrape algae off rocks when submerged.

Fjord Estuaries

Narrow, much deeper than other estuaries. Estuarine circulation is restricted to depths above the sill (partially mixed or salt wedge). Mixing is somewhat enhanced by turbulence at the sill. Vertical mixing does not reach the bottom waters and many have hypoxic or anoxic bottom waters.

Low Tide Zone

No threat of desiccation (moisture loss) high wave action. plentiful nutrients brought by tides Dominated by macroalgae (Chondrus crispus), encrusting algae Anemones, sponges, sea stars, shrimps, nudibranchs, crabs, fish, filter feeders. No mussels - eaten by sea stars.

Sargasso Sea

No upwelling or big source of nutrients, low Primary Productivity. Sargassum transported to Sargasso Sea via the Gulf Stream. Gyre currents corral Sargassum sp. to allowing it to persist. Provides food and shelter for many species of slow-growing invertebrates and fishes. Recognized as essential fish habitat by USA, ICCAT Important ecosystem for conservation and economics Threats: Pollution: Same currents that corral Sargassum also corral plastics and other debris. Overfishing. Shipping.

Non-indigenous Species

Nonindigenous species -introduced via ship ballast water, attached to ship hulls and in many other ways Can also be deliberately introduced for commercial, recreational purposes. Nonindigenous species can be invasive if they outcompete natives.

coastal upwelling

Nutrient rich bottom waters are upwelled to replenish depleted surface waters and fuel primary production In coastal upwelling regions, the distribution of water properties and biota is related to the upwelling circulation. Upwelled water, high in nutrients, supports only low levels of primary production at first, but as it moves offshore as the surface layer, it supports a diatom bloom that depletes the nutrients, after which flagellates become dominant. Zooplankton and fish species take advantage of this distribution of food. Many species of plankton use the upwelling circulation by changing their depth to be transported either onshore or offshore. Many fish and invertebrate species also use this circulation by placing their eggs and larvae at the right place and depth so that they are transported to a location where the appropriate food source is available at different stages of their life cycle. West Africa coast and California coast, are both on west coasts, with eastern boundary currents (flowing toward the equator) Upwelling off the coast of Africa. Note the "warmer" colors near the coast representing increased PP fueled by nutrients from upwelled water.

nekton

Organisms that live in the water column and that are able to swim actively. Nekton include: §fishes §squid and other cephalopods §marine mammals §a few species of marine reptiles and birds

Brooders

Oviparous means egg laying. This Banggi cardinalfish holds his eggs in his mouth for protection, but many species lay their eggs on the seafloor. What are the tradeoffs? Many pelagic juveniles are eaten by predators so species must produce large quantities of fertilized eggs. This fish is solving that problem by giving some parental care.

Organic Contaminants

PAHs - burning biomass, fossil fuels; also in oil, creosote PCBs - lubricants, heat conductors, electrical transformers, plasticizers PBDEs - flame-retardants. PFOS - refrigerants, surfactants, fire retardants, lubricants

mid latitudes

PP is light-limited in winter. A spring bloom occurs in spring until nutrients are depleted. Weaker fall bloom - as cooling, storms mix nutrients back to the photic zone. Distinct seasonal cycle well-mixed water column in winter; shallow thermocline in summer. §Spring: High river discharge initiates phyto bloom. §Zooplankton production rises rapidly in response. §Bloom continues until nutrients deplete. §Phytoplankton biomass does not rise during bloom (consumed by zooplankton) Production (rate) = amount of carbon produced over time Biomass (concentration) = cells per volume of water Mid-Latitude Phytoplankton Species Succession Typical sequence of phytoplankton species dominance during spring and summer: à Diatoms dominate until silica is depleted and are then replaced by flagellates.

Suspension Feeding

Pelagic Benthic Methods of suspension feeding: •Actively pump water through the filtering apparatus •Move the filtering apparatus through the water •Keep the filtering apparatus stationary and let the ocean currents move though it

Feeding Tradeoffs

Pelagic Suspension: There are many predators in the water column, food is dilute in the water column, it costs energy to filter the water. Benthic Suspension: It's safety from predators if you live in sediments but there isn't much food there so that's why it would filter feed from the water column. Surface Grazing: You are exposed to predators but there is a lot of food on the seafloor surface. Many organisms move slowly or are completely immobile, but reproduce quickly to compensate. Deposit Feeding: You are protected from predators but you have to go through a lot of sediment to find enough food. Their food is mostly bacteria and other microbes. If you want to live in the sediments, you need some method of breathing or respiration. This restricts deposit feeders to the top layers of sediments where they can acquire oxygen. Deposit feeders tend to be mostly annelid worms.

Habitat Tradeoffs

Pelagic: costs energy to swim around, if you float around you can't decide where you want to go if food isn't abundant where you happen to float you could be in trouble Benthic epifaunal: you are exposed to predators if you just sit on the seafloor, you don't have to spend energy swimming or staying buoyant in the water, lots of food Benthic infaunal: protection from most predators, little food, if you go too deep the sediments run out of oxygen due to respiration from bacteria and lack of mixing with the oxygenated seawater.

Photosynthesis

Photosynthesis - carried out by phytoplankton and cyanobacteria §The dominant process of primary production (PP) in the oceans is photosynthesis. §Photosynthetic requirements: carbon dioxide, water, nutrients, and energy (sunlight). §PP can be light-, nutrient-, C-limited (rarely C-limited).

Rocky Intertidal Ecosystem

Physical limitations determine upper boundaries of species range. Competition/predation determine lower boundaries of species range Supralittoral Zone: Always out of water; in splash zone High Tide Zone: Submerged at high tide Middle Tide Zone: Exposed at low tide; otherwise submerged Low Tide Zone: Always submerged

Plastics and Trash

Plastics do not decompose readily in oceans Dumped into the oceans, lost overboard by vessels, wash into the oceans from rivers The plastics include fishing nets, and fishing line that can entangle birds, mammals and fishes and kill them Plastics break down into small particles consumed by marine species but not excreted through the gut. They accumulate and can eventually cause the animal to starve great pacific garbage patch Plastics can cause more than just aesthetic problems in the marine environment. The plastic items above were found in the stomach of a juvenile Laysian albatross and likely contirbuted to its death

Sources of contaminants in estuaries

Point Source: emitted from a defined location (like a sewage treatment plant) Nonpoint source: emitted from diffuse or undefinable location. - More difficult to manage.

Organic Pesticides

Poisons (insecticides, herbicides) Organochlorine, organophosphorous, carbamates, aromatics, dioxins, DDT, pyrethroids Kepone - produced in Hopewell, VA in 70s - Caused closure of James R. to fishing due to fish, shellfish contamination

Habitat Alteration

Salt marsh, mangrove, coral reef, rocky intertidal habitats threatened on both sides by "coastal squeeze." - Rising sea levels shrink habitat on seaside. - Anthropogenic activities shrink habitat on land side. Loss of ecosystem function - nursery habitat, bird habitat, nutrient, contaminant filtration Other threats to salt marshes: Tidal restriction, filling, dredging Trawling: Degrades benthic habitat (dragging a net through bottom of ocean)

Sewage

Sewage: high concentrations of dissolved and particulate natural organic matter contaminated by industrial and domestic sources of toxic substance also contains human pathogens Treatment removes some pathogens, nutrients, toxics, organics, but rest is discharged to rivers, estuaries, oceans.

electrosensing

Sharks have special pores called Ampullae of Lorenzini that they use to sense bioelectrical signals in the water. This can aid in hunting.

Rocky Intertidal Communities

Species have their upper limit defined by physical environmental stressors, lower limit by competition/predation Variable water exposure (desiccation) Variable oxygen concentrations and pH *Predation (birds, terrestrial animals) Temperature swings Variable salinity Wave energy

Sargasso Sea summary

Stressors (in absence of Sargassum): low nutrient, low productivity waters lack of structure for habitat/protection from predators In Sargassum food source unique habitat offering protection from larger fish predators Adaptations: efficient recycling of nutrients, resources camouflage coloration patterns unique life histories (e.g., the American eel) long-lived, slow-growing species occupy Sargassum

Beyond the Sun's Light (Aphotic Zone)(Mesopelagic, Bathypelagic, Abyssal Zones)

Stressors/conditions (gradient in severity with depth): Minimal (mesopelagic) to no light. Low and uncertain food supply. Uniformly low temperatures. Increased pressure. Detritus is major food source and decreases with depth.

Polar Ecosystems

Stressors: seasonally low light and low temperature climate warming and habitat loss Adaptations migrations fat stores, fur coats

Surface Grazing

Surface grazers crawl along the bottom of the seafloor in search of abundant food. Grazing can refer to eating plants or animals in the marine use of the word. Some species have scraping teeth. Not all species actually live on top of the seafloor, but some live in the sediments and extend up a siphon tube to "vacuum" up the seafloor surface. What are the tradeoffs? You are exposed to predators but there is a lot of food on the seafloor surface. Many organisms move slowly or are completely immobile, but reproduce quickly to compensate.

Commensalism

The remora (family Echineidae) that rides attached to sharks and other fishes. Remoras have evolved on the top of their heads a flat oval sucking disk structure that adheres to the bodies of their hosts. Both remoras and pilot fishes feed on the leftovers of their hosts' meals.

Sources of Petroleum in the sea

There are many sources of petroleum other than tanker and oil rig accidents The largest sources are municipal waste (sewage) and routine tanker operations, but natural and other sources are also large Exxon Valdez, Alaska (right top and below) and the much larger spill from the Amoco Cadiz in Brittany, France (above). Deepwater Horizon, 2010, Gulf of Mexico (above) IXTOC Gulf of Mexico, 1979 (right) Effects of Major Spills Major oil spills from the offshore oil industry are rare but dramatic events.

Coastal ocean bathymetry and rivers:

Variable salinity, temp. (e.g., Amazon River plume) Coastal currents can be independent of ocean currents and gyres More sources of nutrients than the open ocean Benthic (bottom) organisms are more diverse, abundant, and commercially valuable

Partially Mixed Estuaries

Vertical mixing is greater in partially mixed estuaries than in salt wedge estuaries. Halocline is weaker. Partially mixed estuaries have strong tidal currents. Water has higher salinity on right side* due to the Coriolis deflection. (*N. hemisphere!)

Live Birth (Viviparous)

Viviparous means live birth. Examples are humans, whales, and sharks. What are the tradeoffs? It takes a lot of energy for the mother to grow those juveniles up before giving birth; however the juveniles have a much greater chance of survival.

Dredged Material

With the exception of a few deep-water ports, most ports and harbors do not have sufficient natural depth for vessels to navigate safely and berth Most ports and harbors must be dredged to increase navigable depth The dredged material is contaminated by toxic metals and organic compounds released to the estuary or ocean decades before environmental discharges were controlled by law

Salinity distributions in coastal-ocean water columns

a)High river discharge b)Low river discharge, well-mixed water column c)Strong evaporation, low rainfall, low river discharge, mixed water column d)Strong evaporation, low rainfall, low river discharge, stratified water column (reverse of a); Mediterranean Sea) slide 9 of ch. 13

Adaptations to Avoid Desiccation

barnacles, mussels close opercula protecting respiratory organs, trapping small amounts of water inside. Mobile animals will move with water or hide in wet rock crevices until tide returns. Urchins, sea anemones, sponges restricted to low tide zone (live elsewhere).

microbial loop

component of marine food webs in which dissolved organic material cycles through bacteria and nanoplankton then back to small members of the zooplankton Phytoplankton produce organic matter eaten by zooplankton and fish Internal cycling not shown in simple Zooplankton release fecal pellets, material is recycled by bacteria and fungi, nutrients can be reused Phytoplankton produce more organic matter and the cycle starts again

ecosystems

components of the Earth system that are linked by their similar physical, chemical, geological, and biological characteristics. ecosystem community composition depends on organisms' ability to fill niches defined by the ecosystem pay attention to stressors and adaptations that enable organisms to fill niches in various ecosystems

summary kelp forests

detrital-based food web (decomposers feed on kelp fragments) diverse community: invertebrates, fishes, marine mammals trophic cascade: kelp-urchins-sea otters-seals-whales stressors: predation by seals, sea lions, shark, killer whales rocky seafloor, cold waters (<20ºC) adaptations: kelp have holdfasts to grip rocks kelp have air sacs to float up to surface waters urchins adapted to eat kelp

pelagic

epipelagic (photic zone) mesopelagic benthypelagic Abyssopelagic Hadopelagic

HNLC

high nutrient, low chlorophyll - plenty of nitrogen, why is there not more chlorophyll?? •Low primary production in HNLC regions of the ocean explained by iron limitation •Iron limits net community production in up to 1/3 of the world's oceans

biological pump

is the removal of atmospheric carbon dioxide with storage in the deep ocean, essentially removing it for centuries.

Susceptibility to Climate Change

positive feedback between ice melt and solar energy absorbance exacerbates climate change in cold regions. substantial reduction in permanent sea ice area since 1979. Sea ice is important habitat for ice algae primary producers, polar bears, penguins, seals. Impacts on feeding and breeding grounds are expected to be profound.

compensation depth

production is equal to respiration Above, net autotrophic, primary production is dominant, below comp depth, respiration is dominate Turbidity blocks sunlight, open ocean photic zone deeper

Temperature vs depth in the coastal ocean :

shallow halo and thermoclines relative to the open ocean due to higher mixing In polar environments, there is generally little to no stratification - always cold, always well-mixed. In temperate areas, there is little stratification during winter - cold, well-mixed. In summer, coastal ocean waters are stratified and usually (but not always) hotter at the surface and cooler under the thermocline. In tropical waters, there is little stratification due to low freshwater input.

Eukaryote

sing celled or multi, cells have nucleus and other internal structure, larger than prokaryotes Protista (diatoms, forminfera), brown and red algae Fungi Plantae Animalia (SLIDE 4 of ch. 12)

Seasonal Cycles

slide 22 Ch. 13 Polar and Sub-polar Regions Water column: well mixed year-round. Frequent storms, low light intensity, no thermocline. Nutrients are plentiful. *Can be modified by freshwater inputs. Polar/Sub-polar regions generally have well-mixed water columns due to cold weather, frequent storms, low light intensity. The well-mixed water column results in plenty of nutrients and no thermocline - seasonally or otherwise. This situation can be modified in areas of high freshwater input where freshwaters can set up a thermocline.

lures

the deep sea anglerfish. The bioluminescent lure on its head attracts prey as it glows in the total darkness of the deep sea. Tradeoffs? Predators can find you as well but maybe you can confuse them with your lure. It costs a lot of energy to produce your own light.

Depth and Wave Intensity structure Corals

wave energy is high in "buttress zone" (<~20m) - mostly massive head corals at 20-50 m transition from big head corals to delicate forms >50 m, more delicate forms (soft corals) dominate wave energy moves these depth limits up or down.

Zooplankton

§Consume phytoplankton and pass this energy to the next trophic level § §holoplankton - live entire lives as plankton. ¨Species include krill, CaCO3 shelled foraminifera and pteropods, and silica shelled radiolarians, jellyfish, ctenophores, and salps. § §meroplankton - Zooplankton as eggs, larvae, or juveniles then benthos or nekton as adults. ¨numerous species of crustaceans and echinoderms (such as sea urchins and cucumbers).

Basic Principles of Life

§Life is composed of organized non-random structures Molecules - Complexes - Cells - Organs - Organisms (amino acids, nucleic acids, etc) Seawater: H 66%, O 33%, Cl 0.33%, Na 0.3%... Cells: H 63%, O 26%, C 10%, N 1.4% ... - Maintaining this difference in composition takes energy - Synthesis of complex compounds from simple precursors takes energy

Primary producers require nutrients:

§N, P, and Fe as well as other micronutrients (Si, Zn, Co) that diffuse across cell membrane §Insufficient nutrient concentrations can limit phytoplankton growth. §Sources: atmospheric deposition, OM remineralization, diffusion from sediments, continental runoff (natural and anthropogenic) Sources: Rainwater or dust, microbial loop, land and runoff, sediments §Small size of phytoplankton maximizes their surface area to volume. § à limits sinking, keeps them in the photic zone, maximizes surface area for nutrient uptake § When organismal remains sink below the thermocline, this removes C, nutrients from the upper mixed layer of the oceans - Biological Pump.

Primary Production and Light

§PP is confined to the surface ocean, where light penetrates. §The depth at which photosynthetic organisms can produce only as much organic matter as they need for respiration is called the compensation depth (P=R). §Light can be limited by turbidity.

Plankton

§Pelagic organisms that drift with the ocean currents. §Phytoplankton - photosynthetic autotrophs (primary producers) >99% of the food used by marine animals. §Zooplankton - planktonic herbivores, carnivores, or omnivores. The plankton at any location and time consists of many species of phytoplankton and zooplankton

Food Webs

§Phytoplankton (1st level) are consumed by grazing zooplankton (2nd level), which are consumed in turn by carnivorous zooplankton (3rd level), which are consumed by small fish (4th level), and so on... §These are food chains. §Each level is a trophic level. §Many organisms feed at more than one trophic level, §feeding relationships in the oceans thus form complex food webs or trophic webs.

Secondary Production and Decomposers

§Primary production: synthesis of organic matter (OM) from inorganic compounds. §Secondary production: consumption of OM by heterotrophs and conversion of OM into biomass. §Only ~10% of OM is converted to biomass at each step in a food chain. (10% energy transfer, 90% waste) §Decomposers convert the waste products and/or dead tissues of organisms back to inorganic compounds via bacterial respiration. (microbial loop) Microbial loop is very important source for inorganic nutrients in the open ocean where continental sources do not exist.

microbes

§Prochlorococcus: The smallest (0.5-0.8 µm) known photosynthetic organism, a cyanobacteria §may be the most abundant species on Earth - ~1027 individuals - as many as 100,000 per mL of water. §Prevalent in HNLC and other nutrient-limited parts of ocean. §Marine microbes, including Prochlorococcus, adapt to environmental conditions by acquiring and exchanging genes via viruses. §~1029 bacteria in the ocean (compare that to ~1021 stars in the universe). §~billion species of microbes live in the world's oceans. ~38,000 species L-1 seawater. §Microbial species are everywhere - including extreme high temperature (up to about 250oC) and deep in the ocean crust (1,400 m below the seabed). § §Microbial species are responsible for all the decomposition in the oceans. §control many aspects of ocean chemistry including, for example the nitrogen cycle in the oceans

Biology, nutrients, light, water Temp vary with latitude

§Substantial seasonal variations occur in mid and high latitudes, but not in the tropics and subtropics. §Caveats: Latitudinal boundaries are not strictly defined. Characteristics are modified by local conditions/influences.

Phytoplankton (Primary Producers)

§The most abundant types of phytoplankton: ¨Diatoms ¨Dinoflagellates ¨coccolithophores §Other types include silicoflagellates (silica shells), and cyanobacteria. Primary production: synthesis of organic matter (OM) from inorganic compounds.

Turbulence

§Turbulence mixes nutrient-rich water up into the photic zone. §Long residence time of water (2-3 months) on Georges Bank -> very high productivity Turbulence is caused by the shallow seafloor topography. It mixes nutrients up into the water column. Water circulation around Georges Bank New England is characterized by 2 permanent gyres. One is a clockwise rotating gyre that runs around the edges of Georges Bank. The other is a counterclockwise gyre in the Gulf of Maine. The circulation around the bank causes upwelling of nutrients and retains plankton in the water over the bank so that they are able to reproduce to high population densities. These plankton provide food for large fish populations.

Biological Provinces and Zones

§Two provinces/ distinctly different habitats in the ocean: §Benthic (sediments) §Pelagic (water column) §Each of these are separated into zones based on depth. Each zone is somewhat distinct from the others with respect to: §availability of light §water temperature sediment type

Benthos

§benthos: Organisms that live in or on the sea floor. §very diverse organismal group, dominated by invertebrates. §Exists at all sediment depths - even on the deep sea floor. Requires adaptation to unique environment ¨Deep benthos rely on OM raining down from upper ocean or chemosynthesis ¨Shallow, coastal benthos experience variable conditions. Different types of sediment ¨Mud - organisms can burrow in ¨Solid rock - organisms can attach to or bore into

microbial loop works against biological pump

§nutrients and organic matter are recycled in the euphotic and aphotic zones by decomposers. (microbial loop) §microbial loop recycles nutrients, resists the biological pump §P is recycled efficiently, N is recycled more slowly. §Si, Fe are recycled more slowly, transported to depth.

Primary Productivity is high where

§nutrients are ample - upwelling, near rivers. §western boundaries of the continents (eastern boundary currents) §in a latitudinal band across some of the equatorial oceans §Productivity in high latitudes is seasonally high (nutrients are constantly available, light limits PP except in summer). §PP is lowest in remote, nutrient-limited subtropical gyres

Groins, jetties, inlets and harbors

•A groin is a wall built perpendicular to the beach from the backshore out to beyond the surf zone. •Intended to block the longshore drift so that sand accumulates on the upcurrent side of the groin. •Deplete sand supply to the beach on their downcurrent side, where severe erosion may occur. Barrier island continues to retreat in segment adjacent to the segment along which shoreline erosion control is practiced Inlets are often protected by extending jetties out on either side of the inlet. Aids navigation, protects inlet from erosion. Sand builds up on the upstream side and is eroded from the downstream side. Sand can build up until it spills around the jetty into the inlet where it silts up the channel and requires dredging. §Santa Barbara Harbor, created by building a dog leg jetty §sand accumulated on the upstream side, moved around the jetty into the harbor, forming a sand spit. §Harbor must now be dredged periodically.

Communication

•Attract mates • •Locate prey • •Find suitable habitat Communication can help you find mates, prey, or habitat but it can also expose you to predators. •Fish generate sounds from swim bladders •Snapping shrimp

beaches

•Beaches form in the littoral zone: •Between the seaward boundary of land vegetation and the point where sediment is no longer distributed by waves (~ 10-20 m depth). (according to geological oceanographers!) •This zone includes the coast and shore •offshore - seaward of the breaker zone •near-shore - below the low tide line in the breaker zone (may contain longshore bars) •foreshore - between high and low tide lines •backshore - area between high tide line and point reached by highest storm wave (often cliffs, sand dunes) Wind and weather •Onshore winds carry sand from beaches and deposit it on the backshore above the highest point reached by waves- sand dunes Stabilized by vegetation Sand dunes provide essential protection from waves and storm surge The Littoral Zone- Berms •Berms -- Created by storm wave erosion of sand •Identified where the beach slope steepens abruptly, top of berm is usually flat and the seaward side slopes downward relatively steeply Higher berms are caused by earlier storms Highest berm is called winter berm The Littoral Zone- Scarps •Scarps are steep slopes or miniature cliff formed by normal wave action. (analogous to berms) •Located on beach where wave normally reach during high tides If two scarps are present the highest one was formed when the tidal range was larger (spring tides •The beachfront is a preferred location for constructing houses, condominiums, hotels, marinas, and other commercial establishments. •Structures are built next to the beach are vulnerable to damage by storm waves.

benthic fauna

•Benthic/Benthos: seafloor •Epifauna: Organisms that live on top of the seafloor •Infauna: Organisms that live within seafloor sediments

Asexual Reproduction

•Binary fission: a single-celled organism divides into two offspring •Fragmentation: similar to binary fission only for multi-celled organisms •Vegetative: single individual divides into many tradeoffs?An individual organism can reproduce by itself. Many of the offspring are genetically clones of the parents. Because they are clones, they do have any aggressive behavior towards their colony as they might have towards other individuals of their species (ex: jellyfish Portuguese Man of War). What type of asexual reproduction is this anemone doing? Fragmentation.

Egg laying (Oviparous)

•Broadcast spawning: fertilized eggs are released into the water column to be carried by currents to new suitable habitat • •Brooding: fertilized eggs are carried by a parent until they can hatch What are the advantages and disadvantages of both types? Broadcast spawners can disperse to other suitable habitats to find more food, but have to produce many eggs for enough to survive. Brooders will produce fewer eggs and have a higher survival rate by utilizing some parental care.

Ecology

•Ecology: the study of relationships between species and between species and their environment All species must: •Have adequate food supply at all life stages •Survive to reproduce successfully

Navigation

•Mainly hearing and chemical sensing (like sense of smell) •Echolocation in cetaceans •Recall that light is attenuated quickly in seawater (still some species use vision) •Earth's magnetic field

Organic Carbon (OC)

•Organic matter (OM): the nonliving remains of biological material. •C is the major constituent, OC is quantified as a proxy for OM. •Operationally-defined as particulate or dissolved (see right). §Oceanic OC pools are comparable in size to atmospheric CO2, terrestrial plants. §~660-700 Gt C is dissolved (versus ~20 Gt particulate OC). §OM and OC fuel oceanic heterotrophic respiration. §released as waste materials, delivered from land. §very important for the global carbon cycle. Particulate OC sinking is the key transport mechanism for the biological pump. POC export distribution follows trends found for chlorophyll. Fungi and bacteria live off of organic matter Particulate organic carbon, can mitigate climate change, however it is not a very efficient process

food sources

•Other living organisms • •Nonliving organic particles • •Dissolved organic compounds

Coral Bleaching

•Our best understanding is that this begins to occur when temperatures are too warm. •pH may also be a problem..

water column

•Photosynthetic organisms (photic zone) •Pelagic species •Larvae In the water column, we find photosynthetic organisms up in the photic zone where light penetrates into the water, we find pelagic species who float or swim around the water column, and we often find larvae or juveniles. Pelagic species examples: fish, salps, or mammals. Many species have a free-swimming larval life stage. Photosynthetic organisms live in the photic zone (where light penetrates into the water column) such as phytoplankton. There are many types of phytoplankton: cyanobacteria (blue-green algae, some species are toxic even to humans), diatoms (silicon frustule), dinoflagellates (have a flagellum for swimming, can form symbioses with other species), green algae, and coccolithophores (form calcium-carbonate plates which are layered on top of each other to form a sort of protective shell).

Sexual Reproduction

•Separate-sexes •Sperm and egg combine: •Direct sperm transfer •Sperm/egg released into water column •Hermaphroditism: one organism is both sexes •Sequential: change one sex after the other •Simultaneous: at the same time Why choose sexual reproduction? It increases genetic diversity which allows species to better adapt and survive environmental changes. Direct transfer requires fewer sperm and eggs to be successful, so it saves energy in producing fewer eggs and sperm; however, males and females have to find each other which can cost energy in searching. Some species get together at the same time and place each year to avoid this.

Reproductive Strategies

•Sexual reproduction: separate sexes, combine sperm and egg to form fertilized egg •Asexual reproduction: do not have separate sexes (breaking a piece off of an adult or some cellular division) •Egg laying (outside of body) (Oviparous) •Live birth (Viviparous)

Feeding Strategies

•Suspension feeding: filter water • •Surface grazing: eat what's on top of the seafloor surface • •Deposit feeding: eat what's within the sediments Predation/Hunting (next section)

Associations

•Symbiosis: when two different species live together and interact with one another •Parasitism: one species benefits, the other species is disadvantaged • •Mutualism: both species benefit • •Commensalism: one species benefits, the other species doesn't benefit but doesn't suffer disadvantage •Mobilization: one species can move, the other cannot

Migration

•Typically between feeding grounds and spawning grounds •Consider different life stages benefit from different habitats •Ex: zooplankton vertical diel migration Why migrate? Where does one migrate? Typically it's to go between good feeding grounds and good spawning grounds. It's important to consider an organism's different life stages. Maybe feeding grounds A are really good for the adults, but the juveniles eat a different food so they need to go to feeding grounds B. What are some of the tradeoffs of migrating? It costs a lot of energy to swim all the way across the ocean, but it gives your juveniles a better chance of survival. Examples of migration: Atlantic eel and salmon make huge migrations to reproduce. Eels are called catadromous because they are born in the ocean but live their adult lives in rivers. Salmon start their lives as eggs laid in rivers and then migrate out to the oceans to live their adult lives. The eggs are protected from any predators they would normally encounter in the ocean. Why would they want to do this? It costs a lot of energy to swim around that much every year. The salmon compensate by laying fewer eggs since they have to migrate. If they migrate they can provide their offspring with better food, better habitat, and their juveniles can grow up in an area with fewer predators. Maybe the species would eat all of the food in one region if they chose not to migrate. Migration may allow a species to come together at the same place and time to reproduce and possibly increases genetic diversity. Maybe spawning in this specific location gives the best chance of dispersal, spreading the juveniles off further into the ocean. These migrations may last years!

seawalls

•built to break up or reflect storm waves. •made of large boulders, concrete, or steel •replaces (or covers) beach sand that normally would be eroded by the strongest winter storm waves. •The wall protects the coast for some years. the beach in front of the wall often disappears as sea level rises and the unprotected coast on either side of the wall retreats.

Timescales of Coastal Modifications

•change rapidly (short timescales: storms, earthquakes, landslides, tsunamis; • and slowly (long timescales: wave erosion, river sediment delivery, sea level rise) • • Many processes occur on the same coasts at the same time but at different rates

Tidal Wetlands

•grow on shores protected from wave action. • rely on sediment accumulation to provide physical environment • flat, muddy or vegetated areas covered by water during only part of the tidal cycle. • characterized by an abundance of emergent plants: §marsh grasses in salt marshes §mangroves in mangrove swamp Tremendous ecological value ("ecosystem services"): •Supply organic matter, protection from predators •Attractive places for marine animals to feed. •Habitat for juvenile marine organisms which then migrate to the sea at maturity. •Important feeding area for waterfowl •trap sediments/preserve coastlines. •filter nutrients which reduces eutrophication in estuaries •Provide gorgeous vistas •sequester 'blue' carbon

Niche

•range of environmental variables where a species can survive. •competition with other organisms impacts niche use

Longshore Transport

•waves approach shorelines at oblique angles •net transport of sediments is in the direction to which waves are angled (to the right in the picture below) •this is longshore transport •The result is that exposed coastlines/beaches are naturally altered - not great for human use! Beaches naturally migrate inland as coastal storm erosion transports sand offshore. •Barrier island beaches migrate due to natural processes. •Structures built to prevent those migrations. Seawalls or groins are built to restore beach sand and protect the property from wave damage. •often have unintended consequences.