Limnology final

nueston

surface organisms

plankton

water column organisms

seston

plankton category including poor swimmers and particles that are at the mercy of the current

nekton

plankton category including decent swimmers like larger zooplankton, fish.

benthos

benthic and attached organisms. If low mobility, named for the surface they live on (epi-)

periphyton

generic work for attached algae and associated organisms

microplankon

20-200 micrometers

nanoplankton

2-20 micrometers

picoplankton

0.2-2 micrometers

dissolved material

less than 2 micrometers

mixotroph

organism that can use both autotrophy and heterotrophy

phytoplankton

suspended algae

macrophytes

large, rooted plants

cyanobacteria

prokaryotes, single cells or colonial, some N fixers, some toxic (microcystis, anabaena), A flos aquae sold as supplements

endosymbiosis

chloroplasts of all other producer groups originated from engulfed cyanobacteria

Diatoms

single cells or colonial, silica cell wall, 20% of global photosynthesis, can be indicators of lake productivity through time

cryptophytes and euglenids

single celled, often motile, often mixotrophic, secondary endosymbiosis

secondary endosymbiosis

chloroplast originated from different photosynthetic eukaryote, results in 4 cell membranes

dinoflagellates

single cells, often motile, often mixotrophic, some toxic, secondary endosymbiosis, some are endosymbionts or parasites in multicellular organisms

golden-brown algae

single cells or colonial, some motile flagellates, some silica or calcium cases, some toxic

green algae

single cells, colonial, or multicellular, basal group for vascular plants

bladder wort

mixotrophic macrophyte. Has pouches for catching organisms like copepods

emergent plant

macrophyte growth form with rooted base and much of plant out of water (cattails)

rooted floating plant

macrophyte growth form with rooted base and floating leaves (water lilies)

free floating plants

macrophyte growth form without roots attached to sediment (duckweed)

submersed plants

macrophyte growth form without any contact with surface

role of macrophytes in habitat structure

reduce mixing

stabilize sediments

transport oxygen to sediments

transport nutrients to water column from sediments

limit light penetration

provide surface area for periphyton

nutrients

a substance used by an organisms to survive, grow, and reproduce. Usually inorganic forms of elements available for uptake from the environment and the organic forms subsequently transferred through food webs

users of inorganic nutrients

producers, mixotrophs, some heterotrophic bacteria and fungi

users of organic nutrients

mixotrophs, all heterotrophs

Liebig's law of the minimum

the resource in the shortest supply will be the primary constraint on biological production, can only fill the barrel to the shortest stave

ecological stoichiometry

compare elemental composition of organisms to their available supply

redfield ratio for algae composition

106 C : 16 N : 1 P

nutrient addition assays

experimental process for determining nutrient limitations. Take water and algae same and compare growth with fertilizer and without.

colorimetric method

method for measuring nutrients with reagents that react and turn color

total nitrogen

amount of nitrogen in sample after digestion but no filtration

total dissolved nitrogen

amount of nitrogen in sample after filtration but no digestion

inorganic nitrogen

amount of inorganic nitrogen (ammonia and nitrate) in sample after filtration without digestion

total phosphorus

amount of phosphorus in sample after digestion but no filtration

total dissolved phosphorus

amount of phosphorus in sample after filtration but no digestion

net-autotrophic system

respiration < photosynthesis

net-heterotrophic system

respiration > photosynthesis

gross primary production

total amount of carbon fixed by photosynthesis per area or volume per unit time

net primary production

gross primary production - respiration by producers

community net primary production

gross primary production - respiration by producers and consumers

generic nutrient cycle

1. Nutrient exists in large quantities in an inaccessible form

2. Some process makes the nutrient useable for primary producers in aquatic

ecosystems

3. The nutrient is incorporated into organisms

4. The nutrient is recycled through the food web

5. The nutrient is lost to an inaccessible form or location

inaccessible pool of nitrogen cycle

atmospheric nitrogen (N2)

available forms of nitrogen in cycle

ammonium (NH4+), nitrate (NO3-)

nitrogen fixation

cyanobacteria: N2 -> NH3

lightning: N2 -> NO3

nitrification

bacteria oxidizing ammonia and nitrite

done by chemoautotrophs

requires oxygen

NH3 -> NO2 -> NO3

Denitrification

reduction of NO3 in respiration instead of using O2 in anoxic environments

NO3 -> N2

inaccessible form of phosphorus

geologic minerals, which then get dissolved in water

accessible form of phosphorus

phosphate (PO4-)

internal loading of phosphorus

low dissolved oxygen and high pH promote internal loading of phosphorus, which affects lake productivity

resuspension of phosphorus

getting PO4- back into the available form in the water column. Sediments need to be anoxic with high pH, such as in a stratified super productive lake.

cultural eutrophication

quicker lake aging of transition from oligotrophic to eutrophic in relation to human activity

consequences of cultural eutrophication

increased mass of live and dead matter

increased respiration

decreased DO when not offset with high photosynthesis, such as at night

cyanobacteria and harmful algal blooms

autochthonous food web

photosynthesis by primary producers within stream (green food web)

allochthonous food web

photosynthesis by terrestrial primary producers transported to stream as detritus (brown food web)

detritus

all non-living organic matter

coarse particulate organic matter

detritus classified by size, including leaves, dead fish, logs, plants

CPOM > 1 mm

fine particulate organic matter

detritus classified by size, including suspended or deposited fine particles, fecal pellets, can also include alive things that get mixed up in it

FPOM 1 mm - 0.5 micrometer

dissolved organic matter

detritus classified by size, including organic compounds, and living viruses and bacteria if small

DOM < 0.5 micrometer

leaf conditioning process

CPOM increased in nutritional value for macroinvertebrates with the addition of microbes as it is broken down

shredding

process of breaking CPOM to FPOM by macroinvertebrates

leaching

processes of breaking down CPOM, FPOM, and live organisms into DOM

flocculation

DOM sticking together to become FPOM

green vs brown

green = low biomass, high quality

brown = high biomass (at least seasonally), low quality

River Continuum Concept

chain of allochthonous organic matter and photosynthesis -> local biomass (live and dead) -> respiration and transport

transport upstream becomes organic matter input for downstream, which changes forms as it is moving downstream

consumers are distrubted based on preferred form of organic matter

ecosystem metabolism

balance of photosynthesis and respiration by the full community of organisms at a location

stable isotope composition

provides a means of tracking different sources through a food web (you are what you eat), and see if organisms are eating more aquatic or terrestrial sources of food, or marine vs fresh

fractionation

change in isotope composition between a consumer and its food

quantifying reliance on autochthonous vs allochthonous OM

isotope studies: narrow view of a few taxa, integrated over time

production/respiration ratios: broader view for all taxa, shows variation over time

factors affecting the height of DO peaks

increase: light, nutrients

decrease: scouring, grazing

factors affecting baseline DO

temperature and respiration

filter feeders

consumers that eat small particles (seston), including algae, bacteria, POC.

filter feeder fish examples

carps, paddlefish

freshwater bryozoan

filter feeder, AKA moss animals

many individual live together in gelatinous colonies attached to something

occasional massive colonies in eutrophic lakes

ciliated tentacles direct food into mouth

freshwater sponges

filter feeder

flagellates collar cells draw water in small pores through channels then out main opening

can have symbiotic algae

mollusks

filer feeders- bivalves

high speciation

some reach very high abundances

cilia on gills pull water through inlet siphon, filer, then out outlet siphon

many juveniles are fish parasites

planktonic life stages allows for invasive species to be spread through boats

rotifers

filer feeder

common and important consumers of algae and bacteria with seasonally high abundances

most are benthic

ciliated crown directs food into mouth

insects as filter feeders

mostly benthic in streams and rivers, such as black fly and caddisfly larvae that rely on flowing water

annelids as filter feeders

worms

benthic, not many freshwater species

annelids are intermediate host for C. shasta fish parasite

crustacean zooplankton

filter feeders, include copepods and cladocerans, dominant consumers of seston in pelagic zone of lakes

copepods

crustacean zooplankton

calanoid- most commonly pelagic filter-feeders, plankton in spongebob, ciliated region on head that directs water and food to feeding appendages

cyclopoid- pelagic omnivores, raptorial (select particles rather than filter feed)

harpacticoid- benthic, scrape algae and eat POC in sediments

cladocerans

includes water fleas like Daphnia

filter feed using modified appendages within carapace

filter more when seston concentration is low

spring clear water phase

Spring bloom followed by period of clear water typical of algal succession in many temperate mesotrphic and eutrophic lakes, which then levels back to summer levels. Caused by filter feeders catching up to and overshooting seston production.

cladoceran life cycle in good conditions

asexual reproduction of females when conditions are good

cladoceran life cycle in bad conditions

females will start making males for sexual reproduction

all-female ephippia will be produced, which can be dormant for years until good conditions return

cladocern populations will crash until ephippia hatch

characteristics of grazer-resistant seston

large or colonial

indigestible coating (gel or cell wall)

toxins

this changes photoplankton composition

ways that grazers free up nutrients

excretion

sloppy eating

death

benthification

invasive mussles filter water

water becomes clearer by removing algae

light penetrates deeper, extending littoral zone, shifts thermocline down with warmer water

mussles vs cladocerans

mussels: long-lived, always present, can maintain continual filtering even when seston is abundant, chronically clear water, not usually fish food

cladocerans: short-lived, overwhelmed by high seston abundance, populations need time to catch up to blooms, boom and bust clear water cycles, great fish food

examples of macrophyte herbivores

specialist invertebrates that are secondarily aquatic to follow their food source- millfoil weevil, caterpillars

semi-aquatic vertebrates- moose, turtles, beavers, birds

fish and aquatic generalists- grass carp, crayfish

invasive species

introduced species that establish populations, spread, and later their ecosystems. ex. zebra mussles, eurasian watermillfoil

positive consequences of fish introductions

recreational and commerical harvest

economic benefit

negative consequences of fish introductions

suppress populations of native species

- eliminiation

- hybridization

- disease transmission

- competition

- predation

biotic homogenization

altered ecosystems

biotic homogenization

unique, local communities lost, largely replaced by the same species of fish everywhere

macroinvertebrates

invertebrates that are visible without a microscope that are not zooplankton

includes: flatworms, worms, mollusks, crustaceans, insects

macroinvertebrate functional group- predator

eats animals