NRC 260 Module 1 Need to Know

Fecundity

Fecundity

Number of eggs

Water’s most dense temperature

4°C

allochthonous material

material from outside the body of water (ex. leaf falls into a stream)

3 layers of a stratified lake

1) epilimnion 2) metalinnion 3) hypolimnion

What is the thermocline? Where is it?

Where temperature decreases rapidly with depth, located in the metalimnion

What type of wetland is most nutrient dense?

Marshes

Are bogs groundwater dominated or precipitation dominated?

Precipitation dominated

Factors that affect zonation in Rocky Tidal zone

high— salt spray & dessication

low—tolerance to wave action, competition and predation

Master factor for fish

temperature

the currency of life

energy

does fecundity (increase/decrease) with body size?

increase

describe the growth trajectory of fish

indeterminate growth

1st/2nd order streams

steep slopes, flow quickly, narrower, particulate matter

Higher order streams

flow slowly, wider, deeper, particulate settles

2 most biolimiting factors in the ocean

nitrogen and phosphorus

lake stratification in early summer

warm forming on top, thick layer of cold below

lake stratification in late summer

warm on top, cold below, layers are more even

lake stratification in early fall

thick layer of warm on top, thin layer of cold below

lake stratification in fall turnover

Water turnover occurs as layer temps get closer and densities get closer; warm water mixing

lake stratification in winter

All cold water

lake stratification in spring turnover

Turnover with cold water mixing

3 methods of fish aging

Direct observation, Length-frequency distribution, Calcified structures

Direct observation

Mark-recapture individuals over time.

Problems: time consuming, mortality over time, only tells you how many days older it got but you never know its actual age, have to recapture fish which is hard

Length-frequency distribution

Measure the lengths of large numbers of individual fish. Based on the supposition that lengths of a particular age (or year class) will distributed normally around a mean.

Problems: reliability decreases with increasing age and there is overlap among size classes/age classes

Calcified structures

Count rings on bony structures: Marks that develop because of differences in metabolic activity and growth, Annual marks (change in season), daily marks (diurnal activity, metabolic changes between night and day), and false checks (anything that causes a reallocation of energy such as disease or injury), Can use otoliths, scales (may pick regrown scale), vertebrae, opercula, fin rays, shells, etc.

Calcified structures is gold standard for fish aging

Problems: validation and precision (don't know rings actually represent 1 year), seasonal variation is less prominent in the tropics than temperate regions so it's harder to see differences in the otoliths, tropical species tend to spawn several times throughout the year or have a protracted spawning season, have to kill the fish (can't do on rare or endangered species)

Processes that add or remove individual from the population

Reproduction, mortality, recruitment

Cold water slows/speeds up metabolism?

slows

Heightened senses allow fish to

Feel pressure changes (lateral line) and sensitivity to vibrations (inner ear, otoliths) which allow them to move quickly and in synchronized ways (schools)