Limnology exam 2

How long ago did ice sheets begin to recede

17,000 years ago

moraine

boundary to a body of water deposited by a glacier

glacial scour lake

created by glacial corrosion, like ice cream scoop

Tarn

mountain lake at the head of a glacier as ice rotates, looks like little pool in mountains

graben, fault trough, or rift lake

faults move, crust between faults is in depression, most of the most spectacular lakes

Lake Baikal

probably biggest lake on earth, endemic fish, seal

lakes with so many endemic cyclids

african rift lake, cyclid = bright fish

Uplift lakes

tectonic event, crust rises, falls in the middle like a cake, lake in fall

Coulee lake

lava makes dam

Lake Kivu

up to 1500 ft sediment, anerobic decomp happening, toxic gas being released into water. People pumping methane out to make it less toxic, if an earthquake causes bubble millions die

lakes in carbonate strata

Usually acidic water, forms karst - carbonate and limestone exposed and weathering. makes lake districtsz, dolines = swallow holes. caves, good drainage

Playa lakes

wind started, bison finished. most shallow, circles on prairie

evorsion lake

plunge pool, water falls and erodes rock making pool

Astroblemes

craters from meteors, end up with water and make lake

Exorhic lake

open basin, water reaches ocean eventually. most lakes

Endorhic lake

closed basin, not drained by streams. Evaporation causing some to shrink

Pluvial lakes

sensitive to changes in climate, water level fluctuates. often desert

carometer

rolls along to measure distance

bathymetry

higher number = weirder shape, 1 = circle

relative depth

depth in relation to surface area, big lakes less than 1%, but crater lakes higher

morphometry

what’s in a lake

Morphoedaphic index (mei)

ratio of disolved solids and depth, means nothing with high environmental stress

ring shaped lakes

volcanic craters or astroblemes, + probs more. Hard to functionally compare to other lakes

Ecotone

transition between wet and dry areas

Wetland protection

Only habitat protected nationally and internationally, Ramsar convention

Time of strongest tides

Full and new moon, moon is closest to the earth

Wetland soil

usually anaerobic, lower biodiversity, niche. Productivity high, emergent wetlands most productive ecosystems on earth

Peat

Sphagnum moss on dead compressed moss, weakly acidic, bog mummies

carbon stores

30% of world’s surface carbon, often permafrosted. If earth heats, this will release carbon in the atmosphere

Hydric soil

wetland soil, very dark, less iron more organic matter. Slower to decay

accretion

mix of primary produced biomass and substrate from silt and sediment

water purification in wetlands physical or chemical?

mostly physical

ombrotrophic

recieving nutrients from precip

wetlands and europeans

since colonization, about half NA wetlands gone

Reynold’s number

Index, describes flow. <2000 laminar, moving water usually >2800

Transport

Moving, often along bottom, not too speedy

Erosion

Small particle in the water not on bottom moving around

Deposition

sitting on bottom

Thalweg

deep channel of a river

Aral sea

soviet damming depleated sea, messed up a lot