446 Aquatic Ecology Flashcards Preview

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Flashcards in 446 Aquatic Ecology Deck (279)
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1

why study aquatic ecology

aquatic ecosystems & resources critical to human survival, health, well being

2

ecosystem processes

hydrologic flux, storage
biological productivity
biogeochemical cycling, storage
decomposition
maintenance of biological diversity

3

ecosystem "goods"

food
construction materials
medicinal plants
wild genes for domestic plants and animals
tourism and recreation

4

ecosystem "services"

maintain atmospheric gaseous composition
regulate cimate
cleanse water/air
pollinate crops
generate/maintain soils
store/cycle nutrients
absorbe/detoxify pollutants
maintain hydro. cycles
provide beauty, inspiration, research

5

human disturbances affecting coastal ecosystems

1. Fishing, Pollution, Mechanical habitat destruction, introductions, climate change
(fishing always preceded other disturbances, others change in order)

6

inputs and concerns

organic (livestock), fertilizer, rain, pollutants, pathogens, pharma-care, invasive species, nitrate leaching

7

adverse effects of eutrophication

increased biomass of plankton
shifts in phytoplankton (may be to toxic)
increased epiphytes
coral reef loss
decreased water transparency
oxygen depletion
increased fish kills
loss of desirable fish species
reduction in fish/shellfish harvest
decreased aesthetic value

8

chemical characteristics of aquatic ecosystems

nutrients

9

biological characteristics of aquatic ecosystems

foodweb

10

limnology

the study of inland waters - lakes (both freshwater and saline), reservoirs, rivers, streams, wetlands, and groundwater - as ecological systems interacting with their drainage basins and the atmosphere.

11

algal biomass vs nutrient

chl vs. Total phosphorus (TP)
increasing on log scale but large variation above/below the line

12

why measure TP as nutrient load?

most limiting resource

13

high nutrient, lower than expected Chl (algae)

more large fish, preying on large grazers

14

small algae

larger, efficient grazers
larger biomass
larger planktivorous fish
system is more efficient

15

system with lots of small planktivorous fish

prey upon small grazers
larger algae

16

high density of small fish

low density of large zooplankton
higher Chl (algae)
greener water, lower O2

17

small grazer, shallow lake, Chl vs. TP

high productivity, but less than small grazer system in med-large lake- less O2, less insolation, less space...

18

empirical data

observational

19

experimental data

manipulate variable

20

response of lake ecosystem to nutrient loading experiment

same [nutrient], #large fish vary
w/o large fish = small zooplankton = more algae

21

epilimnion

the upper layer of water in a stratified lake, ~constant T, mixed layer

22

lakes with high grazing, low TP

clear water, more light penetration, more heat deeper, larger metalimnion, less steep T gradient, deeper O2 max, photosynthesis can occur throughout metalimnion

23

metalimnion

thermocline, T changes more rapidly with depth than it does in the layers above or below, highest density, layer of 'stuck' algae

24

indicator of water transparency

secchi depth

25

lake with low grazing, high TP

high Chl = low transparency = low O2, higher and smaller metalimnion, less light penetration, steeper T slope in metalimnion, light just barely penetrates meta., photosynthesis cannot occur throughout metalimnion, O2 goes to 0, system is reducing (like saanich inlet)

26

zooplankton size under high fish density

~80% less than 0.2mm

27

zooplankton size under low fish density

~40% less than 0.2mm

28

hypolimnion

the lower layer of water in a stratified lake, typically cooler than the water above and relatively stagnant, ~constant T, O2

29

algae biomass with time

low grazing= increased biomass w/ t
intense grazing = very low slope, barely increasing

30

TP with time

low grazing = increased TP w/ t
intense grazing = very low slope, barely increasing
low grazing = more algae = more TP