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50 terms

APES Ch. 8 Aquatic Biodiversity

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global ocean
single and continuous body of water, divided by geographers into the Atlantic, Pacific, Arctic, and Indian Oceans (separated by continents)
aquatic life zone
Marine & freshwater portions of the biosphere. Examples include freshwater life zones (such as lakes and streams) and ocean or marine life zones (such as estuaries, coastlines, coral reefs, and the open ocean).
salinity
This property of water primarily determines the distribution of many aquatic organisms.
brackish
This term is used to describe a mix of freshwater and saltwater. Examples include estuaries.
plankton
Small plant organisms (phytoplankton) and animal organisms (zooplankton) that float in aquatic ecosystems
phytoplankton
"drifting plants" includes many types of algae. They are primary producers that support most aquatic food webs. Can be found near shorelines.
zooplankton
"drifting animals" Primary consumers (herbivores) that feed on phytoplankton or secondary consumers that feed on others (of their own kind). They range from single-celled protozoa to large invertebrates such as jellyfish.
ultraplankton
Consists of huge populations of much smaller plankton that are photosynthetic bacteria. They may be responsible for 70% of the primary productivity near the ocean surface.
nekton
strongly swimming consumers such as fish, turtles, and whales that can swim against the current.
benthos
consists of bottom dwellers such as oysters, which anchor themselves to one spot; clams & worms, which burrow into the sand or mud; and lobsters and crabs, which walk about on the sea floor.
decomposers
mostly bacteria. Break down organic compounds in the dead bodies & wastes of aquatic organisms into nutrients that can be used by aquatic primary producers.
euphotic zone
In deep aquatic systems, photosynthesis is largely confined to this upper layer through which sunlight can penetrate. The depth of this zone can be reduced when the water is clouded by excessive algal growth resulting from nutrient overloads.
turbidity
cloudiness [in water]
coastal zone
The warm, nutrient-rich, shallow water that extends from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf. It makes up less than 10% of the world's ocean area but contains 90% of all marine species & is the site of most large commercial marine fisheries. Include estuaries, coastal wetlands, mangrove forests, and coral reefs. Has a high NPP per unit of area due to ample supplies of sunlight & plant nutrients from wind and ocean currents' distribution from the land.
estuaries
where rivers meet the sea. They are partially enclosed bodies of water where seawater mixes with freshwater as well as nutrients & pollutants from streams, rivers, & runoff from the land.
coastal wetlands
coastal land areas covered with water all or part of the year. Include river mouths, inlets, bays, sounds, and salt marshes in temperate zones, and mangrove forests in forest zones.
seagrass beds
Consist of 60+ species of plants that grow underwater in shallow marine & estuarine areas along most continental coastlines. These highly productive & physically complex systems support a variety of marine species. They also help stabilize shorelines & reduce wave impacts.
mangrove forests
tropical equivalent of salt marshes, found along 70% of gently sloping & silty coastlines in tropical & subtropical regions, esp. SE Asia
intertidal zone
area of shoreline between low & high tides. Organisms living in this zone must be able to avoid being swept away or crushed by waves, & must deal with being immersed during high tides & left high & dry (& much hotter) at low tides, as well as changing levels of salinity when heavy rains dilute saltwater.
barrier islands
low, narrow, sandy islands that form offshore, parallel to some coastlines
open sea
vast volume of the ocean
bathyal zone
dimly lit middle zone, which, because it gets little sunlight, does not contain photosynthesizing producers.
abyssal zone
dark & very cold; deepest zone. Has little DO.
marine snow
showers of dead & decaying organisms drifting down from upper lighted levels of the ocean. Reason why abyssal zone teems with life.
deposit feeders
Organisms that take mud into their guts & extract nutrients from it, e.g. worms
filter feeders
Organisms which pass water through/over their bodies & extract nutrients from it, e.g. oysters, clams, sponges
lentic
"standing" ex: lakes, ponds, inland wetlands
lotic
"flowing" ex: streams, rivers
lakes
large natural bodies of standing freshwater formed when precipitation, runoff, or groundwater seepage fills depressions in the earth's surface. Causes of depressions include glaciations, crustal displacement, & volcanic activity. Are supplied with water from rainfall, melting snow, & streams that drain their surrounding watershed.
littoral zone
top layer near the lakeshore and consists of the shallow sunlit waters to the depth at which rooted plants stop growing. Species living here include turtles, frogs, crayfish, & many fishes such as bass, perch, & carp.
limnetic zone
the open, sunlit surface layer away from the lakeshore that extends to the depth penetrated by sunlight. Produces the food & oxygen that support most of the lake's consumers.
profundal zone
the deep, open water where it is too dark for photosynthesis to occur in a lake
benthic zone
lake bottom inhabited mostly by decomposers, detritus feeders, & some fishes. Nourished mainly by dead matter that falls from the littoral & limnetic zones & by sediment washing into the lake
oligotrophic lakes
lakes that have a small supply of plant nutrients; poorly nourished. Often deep and has steep banks
eutrophic lakes
lakes with a large supply of nutrients needed by producers; well nourished. Often shallow with murky brown/green water with high turbidity.
cultural eutrophication
The acceleration of eutrophication of lakes caused by human inputs of nutrients from the atmosphere & from nearly urban & agricultural areas
hypereutrophic
describes lakes with excessive nutrients
mesotrophic
describes lakes that fall somewhere between the two extremes of nutrient enrichment
surface water
precipitation that does not sink into the ground or evaporate
runoff
surface water that flows into streams
watershed
aka drainage basin, the land area that delivers runoff, sediment, & dissolved substances to a stream.
source zone
headwaters/mountain highland streams are usually shallow, cold, clear, and swiftly flowing in this zone.
transition zone
in this zone, headwater streams merge to form wider, deeper, & warmer streams that flow down gentler slopes with fewer obstacles. They can be more turbid, slower flowing, & have less DO.
floodplain zones
In these zones, streams join into wider & deeper rivers that flow across broad, flat valleys. Are usually higher in temperature and have less DO
marshes
inland wetlands dominated by grasses & reeds with few trees
swamps
inland wetlands dominated by trees & shrubs
prairie potholes
inland wetlands that are depressions carved out by ancient glaciers
floodplains
inland wetlands which receive excess water during heavy rains & floods
arctic tundra
In the summer, this wet ecosystem can be considered to be an example of inland wetlands.
seasonal wetlands
wetlands which remain under water or are soggy for only a short time each year, e.g. prairie potholes, floodplain wetlands, & bottomland hardwood swamps