Chapter 7 -- Aquatic Ecosystems

Dams

structures built across streams and rivers to control water flow for purposes like irrigation, hydropower, and flood control

Overfishing

the unsustainable practice of catching fish at a rate faster than they can reproduce

Plankton

tiny animals found at the surface of water; weak swimmers that are carried around by the water’s current

Zooplankton

heterotrophic (eat other organisms to survive); some eat algae and some eat other zooplankton

Phytoplankton

autotrophic (require sunlight); microscopic marine drifting algae

Wetlands

place where the land is covered by water (both saltwater and freshwater can create this)

Flood control

measures taken to try and lessen the damage a flood brings. (Ex: Reservoirs, levees, dredging, Wetlands)

Barrier Islands

island that runs parallel to the coast that protects the mainland

Mangrove Swamps

fresh/salt water; salt loving (halophytic) trees, shrubs and other plants growing in brackish to saline tidal waters; provide protection for coastline and habitats for marine wildlife (buffers between land + sea); lots of diversity

Eutrophication

happens when water becomes overenriched with nutrients which causes excessive plant and algae growth; NITRATES cause eutrophication

Benthic zone

refers to the lowest layer of a body of water, including oceans, lakes, and rivers, where the substrate (bottom surface) is located; zone includes sediment and organisms in it

Benthos

the organisms that inhabit the benthic zone, like worms, mollusks, and algae, which live on or within the sediment

Coral Reefs

underwater ecosystem characterized by reef-building LIMESTONE ridges of coral; formed by clusters of coral polyps that are held together by calcium carbonate

Estuary

bodies of (brackish) water that are usually found where rivers meet the sea

Brackish water

a combination of salt and freshwater. It is often found when a river and sea meet, called an estuary

Salt marsh

a coastal wetlands characterized by salt-tolerant plants, tidal waters, and soil composed of deep mud and peat (made of decomposing plant matter; NOTE: There are NO tall trees.

Rhizoids

root-like structures found in some plants like moss, fungi, and algae that help anchor the organism to the substrate and can also assist in absorbing nutrients and water, although they are not true roots

Coastal Wetlands

low lying stretches of land saturated with water. This includes the entire area from which tidal streams drain to the ocean or inland seas. Found closer inland to beaches and tend to be muddy and have soft ground (marshes and swamps); there can be fresh and saltwater wetlands.

Decomposers

organisms that break down dead and decaying matter; they return matter back into soil so the nutrients can be recycled

Runoff

The draining away of water (or substances carried in it) from the surface of an area of land, a building or structure, etc.; unconfined flow of water over the ground surface; occurs when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil

Bog and Fens

Uncommon wetland communities with water chemistry (pH) at the extremes; BOGS are ACIDIC, FENS are BASIC/ALKALINE SWAMPS

Photosynthesis

system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism

Chemosynthesis

the process by which food is made by bacteria or other living things using chemicals as the energy source, typically in the absence of sunlight

Nekton

living organisms, like dolphins, turtles and fish, in the Earth's water bodies that can swim independently of currents

Littoral Zone

the area close to the shore and extending out to the edge of the continental shelf