Freshwater Ecology

limnology

ecosystem level approach to the study of freshwater (ponds, lakes, streams, rivers, wetlands) and focuses on both biotic and abiotic

Birce and Juday

studied lakes and ponds in northern Wisconsin in early 1900s

Clean water act

enacted in 1972, and was part of the environmental revolution. This regulated point source discharges and protected wetlands

continental glaciers

mode of lake formation that formed Kettle lakes. when the glaciers melted back they left sand, gravel, and buried ice chunks that melted. Tend to be small, round, and have steep sides. Young lakes

Glacial Moraine

mode of lake formation that bulldozed through existing valleys, and as they melted back left natural dams. tend to be long, narrow, and have steep sides.

Glacier formation

natural process where the snow from winter doesn’t melt during the summer, so it accumulates, and the weight of the snow creates ice at the bottom

Glacier scour

mode of lake formation where glaciers carve out bedrock. Make great lakes, and are extremely large and deep

Alpine Glaciation

lake formation process that is still ongoing, starts at the top of mountains where ice pushed down sand and gravel out of place to form Cirque Lakes

Northern Cascades

home to the largest ice field

Volcanic Lakes

mode of lake formation where after an expulsion, a volcano will collapse, leave a caldera, which will then fill with water. Usually incredibly old, deep, and unproductive. Make caldera lakes

Slipped blocks

mode of lake formation where tectonic plates will slip, leaving very deep and very old sunken blocks which will fill with water to become a Grabben lake

Crustal Warping

mode of lake formation where the crust will push up and warp, causing a river to be cut off which turn sit into a lake

landslides

mode of lake formation where rock faults and causes sediment to fall into a river, creating a dam, which creates a slide lake”

oxbow lakes

type of lake where the deposition of silt on the inside bends of low grade rivers will eventually build up and cut off the loop and create a lake

solution lakes

type of lake found in limestone landscapes, can form sinkholes, and can spring a leak and drain rapidly. tend to be round, deep, and have steep sides

change in elevation/distancex100

% gradient

active channel/thalweg(deepest part of stream)

aspect ratio

volume/time

stream discharge

cohesion

weird property of water which forms surface tension, which forms the Neustron which allows organisms to walk on water

Neuston

surface film

viscosity

weird property of water where it sticks to itself

high heat storage

weird property of water which makes it harder to heat up and harder to cool down

universal solvent

weird property of water that makes it so it can dissolve both ionic and non-polar compounds, and lead to the evolution of olfaction sensory organs in aquatic animals

density anomoly

weird property of water that makes it so once its below 4°C, it become less dense

absorption/attenuation

light energy that is transformed into heat energy

epilimnion

surface lake layer that is warm and less dense

hypolimnion

lower lake layer that is cold and dense

thermocline

depth in a lake where the temperature rapidly changes from warm to cold, and is where the epilimnion and hypolimnion are seperated

fall turnover

process where the epilimnion and hypolimnion reach the same temperature by the epilimnion cooling, they become isothermal, and water, oxygen and nutrients fully mix

spring turnover

process where the epilimnion and hypolimnion reach the same temperature by the epilimnion warming, they become isothermal, and water, oxygen and nutrients fully mix

hypoxia

process where the water in the lake has a low oxygen content which can cause fish kills

depth, surface area, fetch

factors that affect stratification

fetch

length that the wind blows across a lake

Dimictic lakes

a lake that turns over twice a year, both in the fall and the spring

Amictic lake

a lake that does not turn over due to being in a stable climate, usually in tropics where its always warm

Meromictic lakes

permanently stratified due to chemicals (usually salts which make it dense) makes a chemocline instead of thermocline

Monomictic lakes

a lake that turns over once a year, has either winter or summer stratification

N2, O2, CO2, H2S, CH4

5 common dissolved gases in freshwater

temperature, salinity, water depth, altitude

physical factors that limit solubility

photosynthesis, atmospheric mixing(turbulent flow), respiration

factors that determine actual concentration of oxygen

summer kill

process where water becomes anoxic on a hot, calm day and causes fish mortality around 6am

winter kill

process where water becomes anoxic due to prolonged ice cover and high microbial respiration rates in productive ecosystems that causes fish mortality in late march or early april

cations

positive charged molecules

anions

negatively charges molecules

Anthropoda: Insecta

phyllum:class for freshwater invertebrates

Mayflies: Ephemeroptera

order

Stoneflies: Plecoptera

order

Dragonflies/damselflies: Odonata

order

True Bugs: Hemiptera

order

Caddisflies: Trichoptera

order

Beetles: Coleoptera

order

True Flies: Diptera

order

dobsonflies, fishflies, alderflies: Megaloptera

order

Decapoda

order

Amphipoda

order

Isopoda

order

Cladocera

order

Copepoda

order