Chapter 8 - Aquatic Biodiversity

Marine Biomes

estuaries, coastal wetlands, coral reefs, the oceanic zone and polar ecosystems

Freshwater biomes

lakes/ponds, rivers/streams, and inland wetlands

plankton

free-floating organisms which have such weak swimming ability that they are at the mercy of the prevailing water movements

phytoplankton

capable of photosynthesis

zooplankton

are animals

nekton

organisms capable of sustained locomotion against the prevailing water movement

benthos

bottom-dwelling organisms without the need for swimming

Red light

is absorbed quickly in the upper meter of water

blue light

penetrates as much as 200m

saltwater ocean coverage

71%

oceans are essential

for regulating global temperature and climate

amount of known marine species

1 million

amount of undiscovered marine species

9 million

neritic zone

extends to the edge of the continental shelf and contains 90% of all marine species

oceanic zone

includes all waters beyond the continental shelf (desert of the sea)

estuary

partially closed area of coastal water where seawater mixes with freshwater

constant water movement from tides

provide for a nutrient rich environment with a ride range of temp and salinity for estuaries

coastal wetlands

areas of coastal land that ware covered with saltwater all or part of the year

importance of wetlands

they filter water, protect shorelines from erosion and provide feeding and breeding grounds for many organisms

marshes

freshwater or estuarine wetlands dominated by grasses (type of coastal wetland)

bogs

inland freshwater wetlands dominated by mosses (type of coastal wetland)

swamps

freshwater, estuarine, or marine wetlands dominated by trees (type of coastal wetland)

mangrove swamps

tropical communities dominates by halophytic (adapted to grow in saline conditions) trees

coral reefs

massive colonies of coral polyps living in a secreted skeleton of calcium carbonate

coral relationships

most coral is is in a mutualistic symbiosis with zooxanthellae (single-cell algae)

coral reef age and growth

coral reefs are among the oldest and most productive ecosystems in the world but most grow at only .5 CM per year

biggest threat to coral reefs

acidification and warming of the oceans. the rising of these factors causes calcium carbonate to dissolve and coral bleaching in which the coral become stressed and expels the zooxanthellae

extra stresses to coral

increased UV radiation, global warming, runoff of pesticides, fertilizers and industrial chemicals

oceanic zone

one of the least productive of all ecosystems because light only penetrates the surface waters

divisions of the oceanic zone

Epipelagic Zone: 0-200 meters

Mesopelagic Zone: 200-1,000 meters

Bathypelagic Zone: 1,000-4,000 meters, 10-4 degrees C

Abyssopelagic Zone: 4,000-6,000 meters, overlaying the plains of the major ocean basins

Hadalpelagic Zone: 6,000-10,000 meters, includes the open water of deep trenches

polar caps

considered marine ecosystems because the primary food source is plankton

arctic ocean

rich in nutrients from surrounding land masses

antarctic

not rich in nutrients lacking the surrounding land masses

freshwater life zones

occur where water with a salinity of less than 1 ppt accumulates on or flows through the surfaces of terrestrial biomes

lentic systems

are standing, such as lakes, ponds and inland wetlands

flowing systems

moving such as streams and rivers

Lakes

large bodies of standing fresh water, formed when precipitation, runoff, or groundwater seepage fills depressions in the earth’s surface

littoral zone

is the shallow area near the shore to the depth at which rooted plants stop growing (lake)

limnetic zone

is the open, sunlit water surface layer away from the shore that extends to the depth penetrated by sunlight (lake)

profundal zone

is the deep, open water where it is too dark for photosynthesis (lake)

benthic zone

is the bottom of the lake (lake)

seasonal changes

occur in temperate lakes, causing an overturn of the water column

during the summer and winter

the water become stratified into different temperature layers, separated by themocline.

in the fall and spring

waters at all layers mix in overturns that equalize the temperates at all depths

watershed

entire land area which delivers water, sediment, and dissolved substances to a stream or river

watershed characteristics

area, length, slope, soil and vegetation

river system

a series of different ecosystems because of different environmental conditions in each of three zones

source zone

contains the headwaters of the river. the zone typically has cold, clear, highly oxygenated

transition zone

the headwater streams merge to form wider, deeper streams. the warmer and slower-moving water supports more biodiversity, particularly phytoplankton.

flood plain

joins streams into wider and deeper rivers that meander across broad, flat valleys. This area supports the greatest number of both plant and animal species

Inland wetlands

include marshes, swamps and bogs along with seasonal wetlands (ex: floodplain wetlands, prairie potholes.) Important for 3 main reasons.

1st important factor of inland wetlands

provide food and habitat for fish, migratory waterfowl and other wildlife

2nd important factor of inland wetlands

filter, dilute, and degrade toxic wastes, excess nutrients, sediments and other pollutants from runoff

3rd important factor of inland wetlands

reduce flooding and erosion by absorbing overflows of streams and lakes