Aquatic ecology exam 1

water molecules

-polar

-covalently bonded

-H+,O-

-melting point 0C, boiling point 100C

-surface tension

hygroscopic water

absorbed by particles and remains on their surface. soil particles "hold on" to water

capillary water

-stays in soil and can rise through soil from ground water

-supports plants long after it has rained

-due to surface tension from hydrogen bonds

A large portion of soil water is there due to what, and what percentage?

high viscosity, 0.005%

gravitational water

drains through soil

Fi

intertial force

Fv

viscous force

u

dynamic viscosity

the boundary layer

the zone which fluid transitions from sticking to the surface to moving freely

larger aquatic animals need to be more

streamlined

what are the main cations in freshwater

calcium, sodium, magnesium, potassium

what are the main anions in water

chloride, sulfate, carbonate, nitrate, nitrite, phosphate

why do salts dissolve in water

the polarity

what are dissolved salts called

electrolytes

the higher the salt content, the higher the __

conductivity

the solubility of ions and inorganic compounds do what at higher temps?

they increase, but not under natural conditions

continental weathering hypothesis

sea salts are derived from rivers, derived from dead sea etc. largely correct but doesn't explain sodium and chloride.

modern theory on how sodium gets in the ocean

leached from rocks on sea floor

modern theory on how chloride gets in the ocean

hydrochloric acid vented from hydrothermal vents and volcanos

what are nutrients

salts dissolved, which is a limiting factor

sources of primary production in aquatic systems

macrophytes, protists, prokaryotes

where do plants get carbon from, terrestrial and aquatic

the atmosphere

which elements are easy for plants to obtain

carbon, oxygen, hydrogen. nitrogen and sulfur typically require bacteria

primary production is limited by what two things

availability of dissolved salts, availability of light

eutrophic

high nutrient content (over 800)

mestrophic

medium nutrients (100-800)

oligotrophic

low nutrient (<100)

where can salts come from, making something eutrophic, naturally

chalk streams or limestones

Whitewater rivers

-nutrient rich

-high flow

-high sediment load (and turbidity)

-plant growth only along edges, low primary production

whitewater floodplains

-nutrient rich

-low flow

-low sediment load (and turbidity)

-high primary production

types of primary production on floodplain lakes

on water surface, open water, coating underwater structures

clearwaters (river and floodplains)

-Precambrian rock formations

-low dissolved minerals

-low primary production (oligotrophic)

blackwaters (rivers and floodplains)

-forested lowlands

-low nutrients

-low turbidity

-low primary production

large amounts of DOC lead to what

low pH

where would biomass be highest

whitewater floodplains

DOCs do not change the __ of water

conductivity

sources of DOC

-leaf litter (kinda like teabags)

-humus (soil+peat)

humic substances are derived from what

decomposed vegetable matter

soils with clay fractions do what to humic substances

sequester it (hide it away)

acidity does what to photosynthesis

suppresses it

blackwaters are what pH

acidic

humic substances are nutrients. True or false

false

what form of carbon do plants take (ONLY)

carbon dioxide, from atmosphere

chelating agents

bind to positively charged multivalent ions, increase uptake ability of plants

detergents

solubilize hydrophobic substances

humic substances can be

-chelating agents (lower acidity)

-detergents

rises in pH will cause humic substances to __

flocculate/clump

Where is there less oxygen, water or air?

water has less

where does oxygen diffuse slower, water or air?

water is slower

percent saturation

amount of oxygen dissolved in the water sample compared to the max. amount that could occur at equilibrium

as temperature rises DO (dissolved oxygen levels) __

decline (think of that hot fishing trip with no fish)

as temperature rises, metabolic rates __

increase

Oxygen inputs

-diffusion

-photosynthesis

oxygen outputs

-organic respiration

-decomposition

supersaturation

shaking the water lol

when is water at max. density

4C

when does water turnover

spring and autumn

holomictic lakes

turnover once a year

dimictic lakes

turnover 2x a year

polymictic lakes

turnover several times a year (tropical/subtropical)

meromictic lakes

-never turnover

-deep, or lots of stream inputs

-saline water sinks to bottom

which has a higher heat capacity, salt or freshwater

freshwater

what aquatic system is the most thermally stable

deep sea

light transmission importance

-photosynthesis

-light detection as a sensory cue

-heats water

which wavelength does water absorb more of

long-wavelength

why is water blue

blue penetrates the most, other colors are absorbed more

water with high DOC are red why?

It absorbs green and blue most, reflects red, due to the humic compounds