APES Chapter 8: Aquatic Biodiversity

global ocean

The body of salt water that covers nearly 3/4 of Earth's surface

aquatic life zones

Marine and freshwater portions of the biosphere

marine life zones

Aquatic life zones that include oceans and their bays, estuaries, coastal wetlands, shorelines, coral reefs, and mangrove forests

freshwater life zones

Aquatic systems where water with salinity that's less than 1%; accumulates on or flows through the surfaces of terrestrial biomes

plankton

Organisms that float or drift freely near the ocean's surface

phytoplankton

Microscopic, free-floating, autotrophic organisms that function as producers in aquatic ecosystems

ultraplankton

Tiny photosynthetic bacteria; accountable for 70% of the primary productivity near the ocean surface

zooplankton

Animal component of the plankton that feed on phytoplankton and other zooplankton

nekton

All organisms that swim actively in open water, independent of currents

benthos

Bottom-dwelling organisms in aquatic systems

euphotic zone

Upper layer of a body of water through which sunlight can penetrate and support photosynthesis

algal blooms

Massive growths of algae and other phytoplankton that are stimulated by abundant nutrients, especially phosphates

turbidity

A measure of the clarity of water

coastal zone

Warm, nutrient-rich, shallow part of the ocean that extends from the high-tide mark on land to the edge of a shelflike extension of continental land masses known as the continental shelf

estuary

A partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea

coastal wetlands

Land areas covered with water all or part of the year

seagrass beds

Large expanses of rooted, submerged, or emergent aquatic vegetation, such as eel grass or salt grass

intertidal zone

Portion of the shoreline that lies between the high and low tide lines

barrier islands

Islands off the coast that protect the wetlands, estuaries, and bays from the direct impact of ocean waves

ocean acidification

Decreasing pH of ocean waters due to absorption of excess atmospheric carbon dioxide from the burning of fossil fuels

open sea

The part of an ocean that is beyond the continental shelf

upwelling zones

Areas of the ocean where cool, nutrient-rich water from deeper layers rises to the surface

bathyal zone

Dimly lit middle zone of the ocean that does not contain photosynthesizing producers because of a lack of sunlight

abyssal zone

The portion of the ocean where light does not penetrate and where temperatures are cold and pressures intense

marine snow

A continuous shower of mostly organic detritus falling from the upper layers of the water column

integrated coastal management

Community based effort to develop and use coastal resources more sustainably

surface water

Water above the surface of the land, including lakes, rivers, streams, ponds, floodwater, and runoff.

lentic

Standing body, like a lake or pond

lotic

Relating to or living in actively moving water.

runoff

Water that flows over the ground surface rather than soaking into the ground

watershed

An ecosystem where all water runoff drains into a single body of water; drainage basin

lakes

Large natural bodies of standing water formed when precipitation, runoff, streams, rivers, and groundwater seepage fill depressions in the Earth's crust

littoral zone

In a lake, the shallow, well-lit waters close to shore

limnetic zone

In a lake, the well-lit, open surface waters farther from shore

profundal zone

The deep, open water where it is too dark for photosynthesis in freshwater lakes

benthic zone

The bottom layer of a water body

oligotrophic lake

A nutrient-poor, clear, deep lake with minimum phytoplankton

eutrophic lake

Lake with a large or excessive supply of plant nutrients, mostly nitrates and phosphates

cultural eutrophication

Overnourishment of aquatic ecosystems with plant nutrients (mostly nitrates and phosphates) because of human activities such as agriculture, urbanization, and discharges from industrial plants and sewage treatment plants

mesotrophic lake

A lake with a moderate level of productivity

source zone

Headwaters or mountain highland stream; usually shallow, cold, clear, and swiftly flowing waters

transition zone

Area where the headwater streams merge to form wider, deeper, and warmer streams; slower-moving and contain less oxygen

floodplain zone

Area where streams join into wider and deeper rivers that meander across broad, flat valleys

delta

A triangular area of land formed from deposits at the mouth of a river.

inland wetlands

Lands covered with freshwater all or part of the time (excluding lakes, reservoirs, and streams) and located away from coastal areas

seasonal wetlands

Lands that remain under water or are soggy for only a short time each year

dead zone

In a body of water, an area with extremely low oxygen concentration and very little life due to decomposition of algal blooms