Freshwater Ecology - Exam 2 COMPREHENSIVE

what is a lake?

a very slowly flowing or nonflowing open body of water in a depression and not in contact with the ocean

lentic

nonflowing (still water)

what percentage of lentic water do lakes make up?

20%

what continent has the highest number of lakes?

North America

what continent has the largest total lake surface area?

North America

what continent has the most volume of water stored in lakes?

Europe

what country has the highest surface area of lakes?

Canada

what country has the highest volume of lake water?

Russia

what freshwater lake has the largest volume of water?

Lake Baikal

lacustrine

habitat w deep, still water

littoral

region lying along a shore

what freshwater lake is the deepest?

Lake Baikal

what freshwater lake is the oldest?

Lake Baikal

what lake is the largest by surface area?

Lake Superior

benthic

bottom

pelagic

open waters

photic

penetrated by light

aphotic

absence of light

lotic

moving water

what is a bathymetric map?

a depth contour map

retention / residence time

the average amount of time a molecule of water stays in a body of water

how can you calculate retention time?

R = V/L (V=water volume, L=loss of water per time unit)

what does this equation assume?

R = V/L

inflow and outflow are equal

how can residence time impact pollution worries?

it’s worse to pollute a lake with higher residence time; it will take longer to get rid of the pollution

what is shoreline development (D_L)?

irregularity or degree of convolution of the shore

what is the equation for shoreline development?

D_L = L/(2*sqrt(piA_0)) (L=length of shore, A_0=surface area of lake)

how does reservoir depth vary?

deep near the dam and become shallower further out in the delta

how do reservoirs impact sediment deposition?

sediment is deposited in the reservoir’s delta and not reaching the ocean, therefore increasing erosion

what is the largest dam in the USA?

the Hoover Dam

what dam has the largest storage capacity?

the 3 Gorges Dam

epilimnion

uppermost layer of stratification

thermocline

middle layer of stratification, usually where the epilimnion and hypolimnion mix

hypolimnion

bottom layer of stratification

what season is this image displaying (referencing Northern lakes)?

summer

what is turnover?

occurs when layers of stratification in a lake become the same temperature and mix

TRUE OR FALSE: if winds are strong enough, stratification can be broken

false; not even a hurricane can break stratification of a lake

why haven’t lakes responded more drastically to climate change?

the high heat capacity of water

what impacts does climate change have on lake stratification changes?

shortening the duration of ice cover and shortening the length of time between fall and spring turnover

monomictic lake

one stratification and one mixing time per year

polymictic lake

mixes and stratifies many times per year

where are polymictic lakes found?

tropical regions

amictic / meromictic lake

never mixes

where can amictic / meromictic lakes be found?

some tropical regions, saline lakes tend to be amictic

what factors determine wave height?

• strength and duration of the wind

• length of the lake affected by the wind

• geometry and materials on the shoreline

which shoreline will experience more erosion: steep shoreline or shallow shoreline?

steep

what is a fetch?

the area of lake being affected by wind

autotroph

self-feeding organism

heterotroph

other feeding organisms

where do autotrophs get carbon from?

CO2

where do heterotrophs get carbon from?

organic Carbon molecules

filterer

filters organic particles out of the water

collector

eats small organic particles from the benthos

shredder

break up large organic material (leaves) into small pieces to get organic material

scraper

remove biofilms from hard benthic surfaces

predator

eats other animals

archaea

single-celled organism with no nucleus or organelles

archaea are only numerically dominant in what type of system?

extreme systems, such as anaerobic water, hot springs, or hypersaline water

bacteria

single-celled organisms without organelles or a nucleus

TRUE OR FALSE: bacteria have a greater active biomass than any other group on Earth

true

phytoplankton

floats freely

periphyton

attached to aquatic vegetation, rocks, and other substrate

benthic algae

grows on bottom sediments

cyanobacteria

blue-green algal bacteria capable of nitrogen fixation and algal blooms

nitrogen fixation

transformation of N2 gas into N that can be used by organisms

heterocyst

a cyanobacterial cell that carries out nitrogen fixation

akinete

heat / drought resistant spore

TRUE OR FALSE: once cyanobacteria are dead, their toxins are no longer a threat

false

golden algae are mostly in what type of lake?

oligotrophic

facultative heterotroph

an organism capable of switching between autotrophy and heterotrophy

Xanthophyceae

yellow-green algae

what class are yellow-green algae?

xanthophyceae

what do xanthophyceae have that gives them their color?

carotenoids and chlorophylls

how many cilia do xanthophyceae have?

2 (1 hairy, 1 smooth)

frustule

the silica glass cell wall of a diatom

what type of algae are diatoms?

periphyton

how many cells does a single green algae organism have?

one to complex multicellular

what pigments do green algae contain?

chlorophyll a & b, carotenoids

how do green algae store nutrients?

as starch and cellulose

which algae is thought to be the lineage that led to higher plants?

green algae

what shape chloroplast does zygnema have?

star-shaped

what shape chloroplast does spirogyra have?

spiral-shaped

what green algae attaches to turtle shells?

basicladia

detritus

debris in water (leaves, wood, other waste)

what type of heterotroph are fungi mostly?

decomposers

which fungi species is causing amphibian species declines and extinctions?

Batrachochytum dendrobaditis

what is peat?

mostly dead sphagnum

where is sphagnum dominant?

peat bogs

are mosses vascular or nonvascular?

nonvascular

are liverworts vascular or nonvascular?

nonvascular

where are liverworts mostly found?

banks of streams, marshy ground, damp soil

macrophyte

aquatic plant

hydrophyte

aquatic plant

emergent plant

roots underwater but leaves and reproductive parts are out of the water

floating attached plant

floating leaves/flowers but anchored by roots

floating unattached plant

freely-floating plants not anchored

submersed plant

plant completely underwater

sedge

grasslike plant

Carek grayii

sedge that has a spike-ball flower that appears in May and persists through the summer

what is the gulf coast’s worst invasive plant?

water hyacinth

what type of macrophyte is a water hyacinth?

floating