Aquatic Ecosystems

Question 1

salinity

Answer 1

proportion of solutes dissolved in water in natural environments

• often designated in g of solute/kg of water
• cited: parts per thousand

Question 2

turbidity

Answer 2

cloudiness of water caused by sediments and/or microscopic orgs
- determines water c penetration

Question 3

turnovers

Answer 3

(lake ecology) complete mixing of upper & lower layers of water of diff. temps
- occurs each spring & fall in temperate-zone lakes

Question 4

thermocline

Answer 4

steep gradient (cline) in environment temperature, such as occurs in a thermally stratified lake or ocean

Question 5

lake

Answer 5

large enough body of water that water can be mixed by wind & wave action

Question 6

pond

Answer 6

small water source

- smaller than lake

Question 7

littoral zone

Answer 7

shallow water near shore that receives enough sunlight to support photosynthesis

• may be marine or freshwater
• often flowering plants present
• “seashore” zone

Question 8

limnetic zone

Answer 8

open water (not near shore) that receives enough sunlight to support photosynthesis

Question 9

benthic zone

Answer 9

area along bottom of an aquatic environment

• present in most aquatic ecosystems
• nutrient rich (dead decomposing bodies)
• “depth” zone

Question 10

photic zone

Answer 10

(aquatic habitat) water shallow enough to receive some sunlight (whether or not it is enough to support photosynthesis)

Question 11

optic zone

Answer 11

deep water receiving no sunlight

Question 12

plankton

Answer 12

drifting organisms (animals, plants, archaea, or bacteria) in aquatic environments

Question 13

detritus

Answer 13

layer of dead organic matter that accumulates @ ground level or on seafloors & lake bottoms

Question 14

wetland

Answer 14

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

Question 15

emergent vegetation

Answer 15

plants (in an aquatic habitat) that extend above the water surface

Question 16

bog

Answer 16

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)

Question 17

marshes

Answer 17

wetland dominated by grasses & other nonwoody plants

WMGN

Question 18

swamp

Answer 18

wetland that has a steady rate of water flow & is dominated by trees & shrubs

WSTS

Question 19

stream

Answer 19

bodies of water that move constantly in one direction

• creek = small stream
• river = large stream
• well-oxygenated b/c of tumbling H2O = mixing

Question 20

estuary

Answer 20

where ocean & river meet

• freshwater & salt water mix
• include: saline marshes & body of water
• most productive environment

Question 21

ocean

Answer 21

continuous body of salt water

- uniform chemical composition

Question 22

interidal zone

Answer 22

region btwn low-tide & high-tide marks on a seashore

• “btwn tide” zone
• nutrient rich

Question 23

neritic zone

Answer 23

shallow marine water beyond interidal zone

• extends down about 200 m, where continental shelf ends
• nutrient rich

Question 24

continental shelf

Answer 24

portion of a geologic plate that extends from a continental under seawater

Question 25

oceanic zone

Answer 25

waters of open ocean beyond continental shelf - "open ocean" zone - loses nutrients - desert zone of the ocean

Question 26

coral reef

Answer 26

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

Question 27

physical factors that affect orgs inhabiting aquatic ecosystems

Answer 27

(1) salinity (2) water depth (3) water flow & movement (4) nutrient availability

Question 28

how salinity affects org inhabitation in aquatic ecosystems

Answer 28

(1) affects osmosis (2) affects water balance in orgs low S (body) + high S (environment) = water loss

Question 29

how water depth affects org inhabitation in aquatic ecosystems

Answer 29

(1) water absorbs & scatters c (2) c available mostly on surface of H2O (3) turbidity determines c penetration more H2O depth = less c available

Question 30

causes of turbidity

Answer 30

(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

Question 31

how water flow & movement affects org inhabitation in aquatic ecosystems

Answer 31

(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

Question 32

how nutrient availability affects org inhabitation in aquatic ecosystems

Answer 32

(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

Question 33

ocean upwelling

Answer 33

nutrient-filled H2O replaces surface H2O via wind

Question 34

lake turnover

Answer 34

dense nutrient precipitation -> mixed w/ high O2 conc. on surface - occurs throughout year: winter stratification, spring turnover, summer stratification & fall turnover

Question 35

stratification

Answer 35

layering

Question 36

winter stratification

Answer 36

occurs in lake turnover - high O2 conc. on H2O surface - high nutrients @ bottom - temp. layers: 0° C, 2° C, 4° C & 2° C

Question 37

spring & fall turnover

Answer 37

occurs in lake turnover | - diff. layers mix @ 4° C

Question 38

summer stratification

Answer 38

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

Question 39

types of freshwater & marine aquatic environments

Answer 39

(1) lake & pond (2) wetland (3) stream (4) estuary (5) ocean

Question 40

orgs living in a LAKE

Answer 40

``` flowering plants (litteral zone) photosynthetic orgs (limnetic zone) plankton (photic zone) rooted plants (shallow photic zone) detritivores (benthic zone) ```

Question 41

physical factors of a LAKE

Answer 41

high latitudes | littoral & limnetic zone

Question 42

orgs living in a WETLAND

Answer 42

``` "indicator plants" emergent vegetation lack trees marshes = grass, reeds & non-woody vegetation swamps = trees & shrubs ```

Question 43

physical factors of a WETLAND

Answer 43

``` saturated soil only shallow H2O bogs = no H2O lack nitrogen slow, steady H2O flow acidity ```

Question 44

orgs living in a STREAM

Answer 44

- small, fast-moving = no photosynthetic orgs - fast-moving = fish, insect larvae, mollusks & otro animals - wide stream = algae & plants

Question 45

physical factors of a STREAM

Answer 45

``` sometimes high turbidity mouth = warmer, larger & slower fast-moving stream = more O2 slow-moving stream = less O2 wide stream = more organic matter & nutrients ```

Question 46

orgs living in an ESTUARY

Answer 46

``` young fish nursery vegetation benthic invertebrates plankton high species diversity residential & seasonal birds feed here ```

Question 47

physical factors of an ESTUARY

Answer 47

freshwater & salt H2O mix here salinity varies nutrient rich b/c sediments deposited @ slower mouth

Question 48

orgs living in an OCEAN

Answer 48

- 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

Question 49

physical factors of an OCEAN

Answer 49

``` intertidal zone: rocky, sandy or muddy beach neritic zone: nutrient rich continental shelf oceanic zone benthic zone tides ```