Aquatic Ecosystems Flashcards
LG19
salinity
proportion of solutes dissolved in water in natural environments
- often designated in g of solute/kg of water
- cited: parts per thousand
turbidity
cloudiness of water caused by sediments and/or microscopic orgs
- determines water c penetration
turnovers
(lake ecology) complete mixing of upper & lower layers of water of diff. temps
- occurs each spring & fall in temperate-zone lakes
thermocline
steep gradient (cline) in environment temperature, such as occurs in a thermally stratified lake or ocean
lake
large enough body of water that water can be mixed by wind & wave action
pond
small water source
- smaller than lake
littoral zone
shallow water near shore that receives enough sunlight to support photosynthesis
- may be marine or freshwater
- often flowering plants present
- “seashore” zone
limnetic zone
open water (not near shore) that receives enough sunlight to support photosynthesis
benthic zone
area along bottom of an aquatic environment
- present in most aquatic ecosystems
- nutrient rich (dead decomposing bodies)
- “depth” zone
photic zone
(aquatic habitat) water shallow enough to receive some sunlight (whether or not it is enough to support photosynthesis)
optic zone
deep water receiving no sunlight
plankton
drifting organisms (animals, plants, archaea, or bacteria) in aquatic environments
detritus
layer of dead organic matter that accumulates @ ground level or on seafloors & lake bottoms
wetland
shallow-water habitats where soil is saturated w/ water for at least part of the year
- presence of “indicator plants,” which grow only in saturated soils
emergent vegetation
plants (in an aquatic habitat) that extend above the water surface
bog
freshwater wetland that has no or almost no water flow, resulting in very low oxygen levels & acidic conditions
- accumulate peat
- low pH 4
- few plants
- plants adapted to high acidic conditions (ie. venus fly trap)
marshes
wetland dominated by grasses & other nonwoody plants
WMGN
swamp
wetland that has a steady rate of water flow & is dominated by trees & shrubs
WSTS
stream
bodies of water that move constantly in one direction
- creek = small stream
- river = large stream
- well-oxygenated b/c of tumbling H2O = mixing
estuary
where ocean & river meet
- freshwater & salt water mix
- include: saline marshes & body of water
- most productive environment
ocean
continuous body of salt water
- uniform chemical composition
interidal zone
region btwn low-tide & high-tide marks on a seashore
- “btwn tide” zone
- nutrient rich
neritic zone
shallow marine water beyond interidal zone
- extends down about 200 m, where continental shelf ends
- nutrient rich
continental shelf
portion of a geologic plate that extends from a continental under seawater
oceanic zone
waters of open ocean beyond continental shelf
- “open ocean” zone
- loses nutrients
- desert zone of the ocean
coral reef
large assemblage of colonial marine corals that usually serves as shallow water, sunlit habitat for many other species as well
- rain forests of the ocean
physical factors that affect orgs inhabiting aquatic ecosystems
(1) salinity
(2) water depth
(3) water flow & movement
(4) nutrient availability
how salinity affects org inhabitation in aquatic ecosystems
(1) affects osmosis
(2) affects water balance in orgs
low S (body) + high S (environment) = water loss
how water depth affects org inhabitation in aquatic ecosystems
(1) water absorbs & scatters c
(2) c available mostly on surface of H2O
(3) turbidity determines c penetration
more H2O depth = less c available
causes of turbidity
(1) natural - erosion of river sediments by floodwaters & coastal sediment erosion by wave action
(2) human acts - agricultural field run-offs + algal blooms = nutrient pollution
how water flow & movement affects org inhabitation in aquatic ecosystems
(1) presents physical challenge - sweep some orgs away
(2) affects H2O, c & nutrient availability
fast near stream source = > O2 + clear/low nutrients
slow downstream H2O = < O2 + > turbidity + > nutrients
how nutrient availability affects org inhabitation in aquatic ecosystems
(1) nitrogen & phosphorus = short supply
(2) washed away or @ bottom - moving or calm water
(3) scarcity limit growth rates in photosynthetic orgs
(4) ocean upwelling
(5) lake turnover
ocean upwelling
nutrient-filled H2O replaces surface H2O via wind
lake turnover
dense nutrient precipitation -> mixed w/ high O2 conc. on surface
- occurs throughout year: winter stratification, spring turnover, summer stratification & fall turnover
stratification
layering
winter stratification
occurs in lake turnover
- high O2 conc. on H2O surface
- high nutrients @ bottom
- temp. layers: 0° C, 2° C, 4° C & 2° C
spring & fall turnover
occurs in lake turnover
- diff. layers mix @ 4° C
summer stratification
occurs in lake turnover
- thermocline occurs here
- surface layer: high O2 conc.
- bottom layer: high nutrients
- temp. layers: 20° C to 8° C to 6° C to 4° C
types of freshwater & marine aquatic environments
(1) lake & pond
(2) wetland
(3) stream
(4) estuary
(5) ocean
orgs living in a LAKE
flowering plants (litteral zone) photosynthetic orgs (limnetic zone) plankton (photic zone) rooted plants (shallow photic zone) detritivores (benthic zone)
physical factors of a LAKE
high latitudes
littoral & limnetic zone
orgs living in a WETLAND
"indicator plants" emergent vegetation lack trees marshes = grass, reeds & non-woody vegetation swamps = trees & shrubs
physical factors of a WETLAND
saturated soil only shallow H2O bogs = no H2O lack nitrogen slow, steady H2O flow acidity
orgs living in a STREAM
- small, fast-moving = no photosynthetic orgs
- fast-moving = fish, insect larvae, mollusks & otro animals
- wide stream = algae & plants
physical factors of a STREAM
sometimes high turbidity mouth = warmer, larger & slower fast-moving stream = more O2 slow-moving stream = less O2 wide stream = more organic matter & nutrients
orgs living in an ESTUARY
young fish nursery vegetation benthic invertebrates plankton high species diversity residential & seasonal birds feed here
physical factors of an ESTUARY
freshwater & salt H2O mix here
salinity varies
nutrient rich b/c sediments deposited @ slower mouth
orgs living in an OCEAN
- intertidal zone: orgs that w/stand pounding waves, dessication & high T @ low tide (more sunlight & productivity)
- neritic zone: major marine fisheries (coral reefs, mutualistic algae) & orgs live here
physical factors of an OCEAN
intertidal zone: rocky, sandy or muddy beach neritic zone: nutrient rich continental shelf oceanic zone benthic zone tides
