BIO360 Exam 3
What types of estuaries are there?
1.Coastal plain - drowned river valley -Between glacial periods -Water floods low-lying plains and river basins -Chesapeake Bay, Long Island Sound, Narragansett Bay 2.Tectonic estuary -Earthquake causes land to sink & SW covers -San Francisco Bay 3.Fjord -Glaciers cut deep valleys in coast -Filled with water forming fjords -Scandinavia 4.Bar-built -Currents and tides deposit sediment on seaward side -Barrier islands - Cape Hatteras, Texas coast
Describe 8 types of hard corals in terms of their structure & typical habitats where they occur.
1.Encrusting: low spreading, adhere to rocky surfaces, less prone to breaking 2.Massive: ball boulder shape, slow growing, stable 3.Foliase: whorl-like, open flower petal pattern, large SA 4.Branching: numerous branching including secondary branches 5.Columnar: finger-like cylindrical form, no secondary branches 6.Table: broad, horizontal surfaces, large SA 7.Elkhorn: thick and sturdy, antler-like, fast growing, often areas of high wave action 8.Mushroom: flat or dome shaped, oval mushroom-like shape, solitary
What challenges are faced by rocky shore organisms?
Alternately submerged. Exposed to heat, cold, desiccation. Experience drastic changes in salinity. Wave shock - force of waves crashing against them. Special adaptations to withstand wave shock, avoid desiccation, and tolerate thermal changes
What organisms bioluminesce and how common is it among marine organisms?
Animals in 16 phyla, 700 genera are bioluminescent, it is primarily a marine phenomenon - rare in FW. In surface waters (epipelagic)there are many bioluminescent animals and plankton (dinoflagellates) and even ctenophores, polychaetes, tunicates. In the mesopelagic zone 80% of mesopelagic animals are bioluminescent, vertical migrators that have a deep scattering layer, squid, shrimp & other crustaceans, fish (lanternfish, hatchetfish), and sharks (lantern sharks, cookie cutter sharks).
What are salt marshes?
As in other intertidals - distinct bands of vegetation between high & low tide marks
Describe common patterns of bioluminescence.
Bioluminescence can either be extracellular that contain photophores, photocytes (cells), symbiotic bacteria or intracellular that produce or obtain chemicals for light producing reaction. Many organisms with bioluminescence have accessories including lenses, shutters, color filters, and reflectors.
What is bioluminescence?
Bioluminescence is a light producing chemical reaction where a class of light-emitting biological pigments (usually luciferin) increases the O2 requirements of photophores 5X. The reaction is catalyzed by the enzyme luciferase. There are various forms of luciferin.
What are some of the major estuaries on the US east coast and elsewhere in the USA?
Chesapeake Bay, Delaware Bay, Long Island Sound, San Francisco Bay.
What is a lagoon?
Common brackish water habitat similar to estuaries - if FW input then essentially a small version of an estuary. Relatively small area partially isolated by the development of a barrier. Often form when sandbar develops or deposition of sediments enclose part of the sea
What are the dominant plants within salt marshes?
Common grasses include tall & short forms of Spartina (alterniflora & pattens), spike grass (Distchlis spicata), rushes (Juncus gerardi). Determined by combination of physical & biological factors including tolerance of submergence in salt water - (water side of marsh) and competitive ability (land side of marsh). Borders of zones often very abrupt. Upper zones of salt marsh find other grasses, rushes, sedges, plants that cannot tolerate prolonged submergence. Eventually terrestrial plants
Explain the general characteristics of coral reefs in terms of their ecological role.
Coral reefs have high diversity:Structure of coral reef modified by algae, sponges, bivalves & other mollusks, polychaetes, hydrozoans, foraminiferans, thousands of species of fishes. They also supply a large amount of production. They satisfy many niches, many ecological interactions.
Explain the life cycle of an oceanic reef - development of a fringing reef to formation of an atoll.
Corals begin to form when islands sink and corals continue to grow at a similar rate to the sinking of the island. When the inner part of the corals die and covered in debris a lagoon begins to form in that area resulting in a barrier reef that protects the lagoon. An Atoll begins to form when the island continues to sink and becomes completely submerged and forms a small ring of low lying islands. The Atoll reef is then supported on a platform of coral debris build up over millions of years.
Describe growth in corals and some of the factors that influence growth rate of corals (and why they affect growth rate).
Corals grow upward on top of their secreted bottom of calcareous cup/CaCO3 skeletons. Colony also grows in diameter by adding new asexually cloned polyps to periphery and may grow for centuries. Growth rate is heavily influenced by light intensity which is affected by: currents, depth, turbidity, sedimentation, water temperature, day length.
What is tidal overmixing?
Dense SW sinks as lighter FW rises causes mixing. FW flow seaward over the top of more dense SW. Most estuaries are "positive" estuaries of this type. "Negative estuary" FW evaporates more quickly than replaced and inward flow of SW over the top of FW
What are the major primary producers in mudflats?
Diatoms, large algae, and sea grasses
Describe zonation in sandy beach ecosystems.
Filter and deposit feeders-Epifauna. Live on surface - not attached. Burrow dwelling amphipods & crabs. Infauna- live below surface. Many fit between sand grains - worm-shaped. Middle infauna - amphipods, isopods, copepods, lugworms. Lower infauna - polychaete worms, amphipods, clams, sand dollars, crabs
Explain why estuaries are often times very productive.
Freshwater runoff brings nutrients (N, Si), SW brings other nutrients (P). Light, nutrients for not that high of primary productivity. Most of energy input into trophic webs is as detritus. Organic matter in estuaries may be 100x that of open ocean. Detritus in estuarine mudflat can support 100X times more biomass than offshore sediments. Sediments & organisms have high capability to trap & retain nutrients & organic matter
Describe how zonation applies to most intertidal ecosystems.
Gradation in biological conditions from land to sea causes competition and predation. These gradations influence distribution of intertidal plants & animals. Interaction of an organism with the environment (physical & biological) determines the role (niche) of each organism.
Explain what hard corals are and describe their general structure.
Hard corals are hard and have many morphologies related to habitats.
What is a channel?
Home to organisms that cannot tolerate intertidal life in wetlands or on mudflats. Some (crabs, oysters, and killifishes) live in estuarine channels throughout the year. Others only visit the channel to spawn (such as herring & sole).
How is light produced in bioluminescence?
In a chemical reaction when oxygen reacts with luciferin.
Describe body form and swimming mechanisms common to nekton.
In nekton size, and body shape are both a part of how nekton swim. Larger animals can swim more efficiently than smaller ones because they can get from point A to B faster and using less energy. Certain nekton have a body form for improved efficiency of movement. Means of Propulsion helps maximize forward thrust and minimize drag. All of these adaptations result in less energy to move = more energy for reproduction & growth
Describe the salinity gradient in a typical estuary.
Increasing salinity from the river to sea. Variable among types of estuaries.
What are the dominant features of intertidal ecosystems?
Intertidal (above and below the tides). High diversity of living things. Zonation (influence of land & sea)
What are mangroves? Mangals?
Intertidal communities dominated by mangrove plants. Some dominated by one mangrove species. Other mangals exhibit zonation - bands of different mangrove species moving away from water. Range from small shrubs to large (10 m) tall trees. Protected coastal areas in warmer climates -tropics/subtropics. Line about 2/3 of tropical coastlines in the world.
Describe kelp forests and explain how they are highly diverse and productive.
Kelp forests are highly productive due to their high rates of growth - giant kelp 30+ m and high rate of primary productivity. They are biologically diverse communities that contain more niches than flat, soft bottom habitats and have 3-D structure similar to tropical rainforest canopy. They also have a Complex feeding community including: grazers, suspension feeders, scavengers, predators
Describe the general characteristics of mangrove plants.
Leaves - constantly adding to detritus (similar to leaf litter). Roots - rich community of seaweed & animals including sponges, mollusks, crustaceans, fishes. Trunk, stems, leaves - habitat for other animals. Feeding dominated by detritus feeders. Predators move from mangroves to mud and back.
What are the dominant animals found within salt marshes?
Many invertebrates -mussels, amphipods, snails, crabs, clams, shrimp, polychaetes Vertebrates - fishes, predatory birds
Why do marine animals migrate on a seasonal basis?
Many marine animals have areas suited for different segments of the population. Feeding by adults is maximized in one location while development of juveniles is most successful in another and for many marine animals there is even a separate area where adults spawn most successfully. Seasonal migration allows different segments of populations to access different areas for different purposes which benefits the entire population. Seasonal migration ultimately increases survival, growth and fitness (success in passing genes on to next generation).
What kinds of marine animals undergo seasonal migrations?
Many marine animals migrate extensively, but within the ocean (no FW) for example, fishes, marine turtles, whales, lobster, and birds.
Why do marine animals migrate on a daily basis?
Marine animals migrate daily because of predator/prey relationships. Many marine animals migrate for purposes of feeding - even on a daily basis. The benefits of this are enhanced survival & food acquisition. They migrate between areas to maximize food intake & minimize predation risk.
Why do marine animals migrate?
Marine animals migrate for food and reproduction where they move between areas that maximize success at feeding and reproduction. They also migrate for food and safety where they move between areas of refuge and feeding.
How are migration and dispersal related to exploitation of new habitats by marine organisms?
Migration and dispersal both take advantage of a prominent resource in new habitats. Migration usually occurs between feeding and breeding sites and dispersal occurs usually when reproduction has taken place and a larvae needs to find a site to settle which is usually a "good" habitat.
Describe how estuarine organisms overcome the challenge of water and salt balance.
Most estuarine animals are euryhaline - tolerate broad range of salinity. Most estuarine invertebrates are osmoconformers: Concentration of solutes in body fluids (osmolarity) about equal with SW. Tolerate fluctuations in osmolarity. Most estuarine vertebrates are osmoregulators: Expend energy to osmoregulate - maintain constant osmolarity rather than tolerate fluctuations
What is a salt wedge estuary?
Mouths of rivers flowing into SW. FW flows rapidly out to sea at surface. SW flow upstream along river bottom. FW flow rapid & prevents SW from entering further. Wedge moves in and out of river basin with rising/falling tide. One way exchange from SW to FW.
What is nekton?
Nekton are animals capable of swimming to the degree that they can move actively and against water currents.
Differentiate between shelf and oceanic coral reefs.
Oceanic reefs surround islands whereas shelf reefs are along continental margins. There are also 3 sub categories of oceanic reefs: fringing, barrier, and atoll.
How do open ocean animals maintain buoyancy?
Open ocean animals maintain buoyancy with swim bladders (fish) or large oily livers (sharks, skates, rays).
What are oyster reefs?
Oyster reefs habitat for many other organisms. Extensive oyster beds in estuaries along US east coast - Delaware Bay
What are the two major groups of animals common in the open ocean?
Plankton and nekton.
What features characterize the rocky shore ecosystem? Which characteristics tend to be uniform and which ones tend to vary with location?
Regardless of the location, rocky intertidal habitats characterized by periods of submergence & exposure. Common zonation from lowest low tide to highest high tide (sea to land). Height of tidal high and low varies with location as well as influences stress experienced by rocky shore organisms.
What is a well-mixed estuary?
River flow low, tidal currents major role in circulation. Seaward flow of water & uniform salinity at all depths. Salinity decreases as water approaches river.
What are rock reefs?
Rock reefs are hard bottom with several microhabitats (sides and overhangs). They contain suspension feeders (sponges, bryozoans, tunicates) and are adapted to a range of current speeds, maximum feeding at optimal current speed, crevices and spaces between rocks. There are many fish, shellfish, crustaceans. It is well oxygenated and a safe haven from strong currents.
Relate primary producers to trophic interactions that typify neritic waters.
Runoff from continents provides nutrients to waters over continental shelves which supports large and small phytoplankton. Cold waters of Antarctica, N. Atlantic & Pacific dominated by diatoms whereas the North Sea contains a lot of coccolithophores. In warmer coastal waters dinoflagellates are more common. Both polar and tropical seas contain many green algae. Phytoplankton composition varies with location, season and grazing by zooplankton
Describe how estuarine organisms overcome the challenge of remaining stationary.
Small amount have a hard substrate to attach to. Many benthic plants & algae have extensive root systems, rhizoids, stolons, holdfasts to anchor to bottom. Benthic animals: burrow in sediments or attach among plants. Actively swimming animals: move back and forth with the tides
Describe typical soft bottom benthic continental shelf ecosystems.
Soft bottom benthic continental shelf ecosystems have sediments of sand, mud or mixture. In sandy bottoms there are many suspension feeders (filter feed on food in water). In muddy bottoms there are many deposit feeders (process organic matter in sediment). The distribution of organisms is also patchy.
What is a partially mixed estuary?
Strong surface flow of FW & strong flow inward of SW
Describe the temperature gradient in a typical estuary.
Surface water may be cooler in winter than water below, resulting in sinking of cooler surface water and winter turnover and vertical mixing
How are continental shelf ecosystems and humans intimately related?
The continental shelf ecosystems get a lot of sunlight and nutrients which leads to high primary productivity and abundant consumers. It is a benthic habitat often with algae and is the source of most fish and shellfish consumed by humans and protected by countries they border (EEZ).
What is the continental shelf habitat?
The continental shelf habitat is part of coastal seas that extend over the edge of continents that are usually 1 mile to 900 miles wide (average = 40 miles) and descend gradually from shore to depths of about 130 m (430 ft) - then usually steep slope. Rivers carry 750 million tons of sediments from continents to shelf - some deposited on seafloor, some dissolved in SW. Coastal upwelling also supplies nutrients
What is the neritic zone? Describe productivity in the neritic zone.
The neritic zone is the waters above continental shelves. They have an enormous number of phytoplankton beginning food webs. They are "Green" waters which means they have high productivity but they are only about 10% of the ocean by area. And yet, they supply 90% of the world's annual harvest of fish and shellfish. There is a large zooplankton population that is fed on by fish and there are also a lot of marine mammals and seabirds common in this zone.
What is the open sea?
The open sea is water above continental shelf vs earth's crust (not part of continents) which can be viewed as two separate provinces: Neritic - over continental shelf and Oceanic - rest of ocean. Open sea habitat based on vertical location: benthos (bottom), demersal - right above the bottom, and pelagic - water column which can be further divided into epipelagic, mesopelagic, bathypelagic etc. based on depth
What types of migration are there amongst marine animals?
There are daily, seasonal, catadromous (spawn in salt water), anadromous (spawn in fresh water), and amphidromous (move between fresh and saltwater but not for breeding).
Substrate that is hard material (rock), suitable for permanent attachment is found along about ___% of worlds shorelines. a. 5 b. 25 c. 50 d. 75
d. 75
Although estuaries account for a small portion of ocean habitat, about ___% of commercial fish & shellfish of world spend all or part of lives in estuaries. a. 25 b. 50 c. 65 d. 85
d. 85
Mudflats are associated with a number of intertidal ecosystems, but especially with estuaries. Primary production within mudflats is accomplished by: a. Large algae b. Diatoms c. Seagrasses d. All of these
d. All of these
The most important determinant of benthic communities and one which drastically influences the types of organism found there is the _____ of the environment a. Stability b. Salinity c. Temperature d. Depth
d. Depth
Most of the input of energy into trophic webs within estuaries is in the form of: a. Plants b. Algae c. Phytoplankton d. Detritus
d. Detritus
Zooxanthellae that are symbiotic with coral are: a. Plants b. Fungi c. Cnidarians d. Dinoflagellates
d. Dinoflagellates
What are some of the functions of bioluminescence?
escaping predators by startling them or with countershading, they can also attract prey, and communication for courtship/mating and intraspecific signals.
Describe the characteristics that typify the majority of mudflat animals.
They are burrowing animals that feed by suspension, filter, and predation.
Where are coral reefs usually found?
Tropical and subtropical regions (30oN to 30oS) (Water warmer than 18oC). More developed on eastern margins of continents than western margins. Normal salinity SW. Usually within 25-70 m of surface in clear water
Describe typical hard bottom benthic continental shelf ecosystems.
Typical hard bottom benthic continental shelf ecosystems have large sediment not easily pushed aside including boulders, rocks, shells and are most often off rocky coasts. They have a patchy distribution of organisms.Sessile organisms that attach to solid surfaces dominate including bryozoans, hydroids, sponges, tunicates, anemones, bivalves, snails, crustaceans, echinoderms.
Describe the characteristics of a typical sandy beach ecosystem.
Unstable habitat - shifting constantly, waves, currents - populations fluctuate. Life zones are mostly under sand - both vertical and horizontal zonation
Describe zonation in rocky shore ecosystems.
Upper Intertidal (supralittoral): The upper intertidal of rocky shorelines hosts organisms that suffer with frequent desiccation and punctuated food supplies. Middle Intertidal (littoral): The middle intertidal is more densely populated with species more troubled by competition for food and space than physical limitations of the environment. Lower Intertidal (Infralittoral): The lower intertidal hosts a much more diversified assemblage of plants and animals that are exposed to air for only a short period of time each day.
Describe zonation found within coral reef habitats and differentiate between horizontal and vertical zonation and explain how physical and biological factors might influence each type of zonation.
Vertical zonation effects from above 20 m to just below surface. Coral buttresses interspersed with grooves - dissipates wave energy, drains debris & sediment from reef. Coralline algae, robust coral and fast growing many branched species are common - physical environment heavy influences. Whereas horizontal zonation is more affected by biological factors. In the Reef flat, between reef edge and island (or inside lagoon), nearly level surface, may be exposed at low tide, contains wide variety of corals, often drops down to greater depths in the central lagoon. In Lagoons there are calm waters which leads to competition for light & nutrients. One zone - along the back edge of the reef. Other zone = floor of lagoon. Contains giant, elaborate coral colonies & many inverts & fishes
Describe general feeding patterns observed among open ocean animals
Virtually all adult nekton are carnivores and have a variety of means of acquiring diffuse food. They may filter feed on small plankton for example large nekton (baleen whales, whale sharks, basking sharks) and small nekton (anchovies, sardines, mesopelagic migrators). They may also be active predators on other nekton which is by far the most common.
What fishes have elevated body temperatures and what are the advantages of having warm parts?
Warm blooded fish (tuna). Warm blooded fish can swim faster than cold blooded.
What major determinants shape benthic communities found within shelf ecosystems?
Waves, currents, light, and sediments.
What is an estuary?
Where rivers meet the sea. Constant environmental change. Mixing of FW and SW. Often highly productive: Shallow, sunlight, nutrients. Ecological roles: Nutrients to sea, Nursery for many young animals
What are mudflats?
Where water movement reduced. Sediments accumulate - sand, silt & clay (mud) good at trapping nutrients & detritus.
What are zooxanthellae and what is their role in coral reefs?
Zooxanthellae are a general term for photosynthetic cells symbiotic with invertebrate species. They live in Hermatypic coral tissues; they are unicellular algae/dinoflagellates (Protista). They have a symbiotic relationship where corals provide home (stable, protected), nutrients (CO2, N, P) and algae provide oxygen, organic substances (food) and produce 10-100 x carbon necessary for themselves. 90-99% of excess organic carbon (food) transferred to coral. Recycling of nutrients within coral tissues - rapid
There are many more species of coral found in the ____ than in the _____ Ocean: a. IndoPacific/Atlantic c. Atlantic/Indian b. Arctic/Antarctic d. Atlantic/IndoPacific
a. IndoPacific/Atlantic
The one characteristic that best describes estuarine environments and the major challenge that truly estuarine organisms must deal with is: a. Rapid and constant environmental change c. Influx of freshwater b. Influx of salt water d. Anoxic conditions
a. Rapid and constant environmental change
Marine flowering plants are important producers in ___ ecosystems. a. Sea grass b. Salt marsh c. Mangrove d. All of these
a. Sea grass
Coral reefs are almost always found in water warmer than __oC a. 15 b. 18 c. 20 d. 25
b. 18
Mangroves line approximately ___% of tropical coastlines of the world. a. 50 b. 66 c. 75 d. 90
b. 66
A type of oceanic reef located offshore and separated from shore by a lagoon is a: a. Fringing reef b. Barrier reef c. Atoll d. Lagoon reef
b. Barrier reef
Coral belongs to the group of animals: a. Sponges b. Cnidarians c. Mollusks d. Annelids
b. Cnidarians
Although coastal ecosystems are usually highly productive areas characterized by the presence of extensive stands of flowering plants, mangroves, salt marshes and estuaries are all ecosystems where the majority of energy enters trophic webs in the form of: a. Plant matter consumed directly by herbivores b. Detritus c. Bacteria d. Animals
b. Detritus
Many corals have a symbiotic relationship with: a. Diatoms b. Dinoflagellates c. Bacteria d. Red algae
b. Dinoflagellates
Growth rate of corals is most heavily influenced by: a. Temperature b. Light intensity c. Wave action d. Salinity
b. Light intensity
There are many different intertidal ecosystems in different parts of the world that experience a variety of environmental features, but an environmental factor common to all of these ecosystems is: a. Dominance of a few species of benthic invertebrates b. Reliance on detritus feeding by most of the organisms found there c. That they serve as important nursery areas d. That they experience tidal flux (high and low tides)
b. Reliance on detritus feeding by most of the organisms found there
One of the most important variables within estuaries is due to regular and frequent: a. Storms b. Tidal cycles c. Freshwater run offs d. Anoxic events
b. Tidal cycles
What influences the patterns of zonation within intertidal ecosystems?
Environmental conditions: Wave action, tidal cycle, climate, light, slope of shore, size and shape of ocean basin, type of rock, presence of crevices, overhangs, caves
Describe zonation in the open sea and the animals typically found within each zone.
Epipelagic (0-200m): Usually large, effective swimmers, carnivorous, and have well developed sensory mechanisms for navigation and food Mesopelagic (200-2000m): Typically smaller nekton ( <10 cm) that migrate vertically (up and down water column daily). Many have black coloration and large eyes. Many even have photophores (bioluminescence). Bathypelagic (2000m +): Much less known about nekton in this zone. Light present is from bioluminescence and most do not vertically migrate, they rely on sinking food from above. Some have large mouths, and their bodies are small, flabby, reduced skeletons.
Summarize reproduction in corals.
Exhibit both asexual and sexual reproduction. In asexual reproduction they will either bud off new polyp clones or they will fragment which is to break off from the colony. In sexual reproduction they will brood fertilize eggs, or broadcast spawn- releasing millions of eggs in a highly synchronized mass spawning event.
What is the rocky shore?
Extensive shoreline habitat along continents and islands. Substrate is hard material (rock) - suitable for permanent attachment (about 75% of worlds shorelines). Organisms experience submergence and exposure to air. Densely inhabited - great diversity of algae and animals
Waters above continental shelves accounts for about __ % of the ocean by area, but produces about ___% of world's annual harvest of fish and shellfish. a. 5/50 b. 80/40 c. 10/90 d. 27/59
c. 10/90
Coral reefs are rarely found in water colder than __oC: a. 10 b. 14 c. 18 d. 22
c. 18
There are at least 40 definitions that have been proposed to describe what an estuary is, but in simple terms an estuary is: a. A body of water cut off and isolated from the rest of the ocean b. A highly productive enclosed bay characterized by tidal flux c. An area partly isolated from the sea where sea water is diluted by freshwater d. There are no simple terms to describe an estuary
c. An area partly isolated from the sea where sea water is diluted by freshwater
Kelp can reach lengths in excess of 60 feet and can form forests that represent a completely unique marine ecosystem. Kelp is: a. Green algae b. Red algae c. Brown algae d. A flowering plant
c. Brown algae
One of the first to explain how atolls were formed was: a. Jacques Cousteau c. Charles Darwin b. Jackie Webb d. Bob Ballard
c. Charles Darwin
There are many different ways that estuaries may form, but on the US East Coast, the most common type of estuary is a _____ estuary. a. Fjord b. Bar built c. Coastal plain d. Tectonic
c. Coastal plain
The marine ecosystem that most closely resembles a tropical rainforest in terms of three dimensional habitat complexity, high productivity and very high biodiversity is: a. Rocky shores b. Estuaries c. Coral reefs d. Mangroves
c. Coral reefs
We surveyed a number of marine ecosystems in this course and for some ecosystems we could explain the basic ecological processes that characterize marine habitats and communities in a few words. For example, the major characteristic that applies to coral reef ecosystems is: a. Patchy c. High diversity and both horizontal and vertical zonation b. High nutrient input d. Lack of photosynthesis
c. High diversity and both horizontal and vertical zonation
Waters above continental shelves are referred to as the ____ province. a.Pelagic b. Oceanic c. Neritic d. Continental
c. Neritic
The presence of distinct zones with characteristic organisms is a feature common in: a. Salt marshes c. Rocky intertidal habitats b. Coral reefs d. All of these
c. Rocky intertidal habitats
Coral filter feed, but also obtain a significant amount of energy from their symbiotic: a. Algae b. Clownfish c. Zooxanthella d. Spartina
c. Zooxanthella
