aquatic systems and niche

freshwater

1% of water on earth

lentic or lotic,

lotic systems

ecology of running water - rivers and streams

divided into various sections horizontally and vertically

lentic systems

ecology of still water - lakes, ponds, wetlands

limnology

the study of inland aquatic systems

aquatic zones

broad, vertical divisions in both ocean and other zones

• pelagic, benthic

pelagic zone

in the water, off the bottom of the aquatic environment

(epipelagic → bathypelagic)

benthic zone

on the bottom of aquatic environments

(abyssal → hadal in oceans)

epipelagic layer

from the surface to 200 m depth

photic zone - most sun rays can penetrate, photosynthesis occurs, phytoplankton

coastal upwellings

nutrient rich water from the deep comes up and replaces water that moves away from shore on the surface

imp for marine food webs, but can cause eutrophication

phytoplankton blooms of the coasts with incoming nutrients

mesopelagic layer

200 m to 1000 m depth, light can still penetrate, decreasing temp

bathypelagic layer

1000m to 4000m depth

light can’t really penetrate anymore, temp is decreasing a lot

abyssal layer

4000 - 6000m depth

dark and cold

hadal layer

>6000 m depth

the bottom layer of the ocean

wetted channel

water remains all year round

horizontal river division

active channel

will be flooded once per year

horizontal river division

riparian zone

transition to terrestrial, roots of trees, etc

horizontal river division

water column

water from the surface to the floor

vertical river division

hyporheic zone

where surface water meets groundwater

increased nutrient content

hyporheos

elongated, streamlined organisms living in the hyporheic zone

vertical river division

phreatic zone

ground water

vertical river division

phreatobites

small amphipods adapted to living in groundwater

no eyes, no light, lack pigmentation

can also be very small snails

littoral zone

along lake edge

limnetic zone

open lake, anything not along the edge

lake stratification

epilimnion, metalimnion, hypolimnion

(limnetic zone)

epilimnion layer

warm layer at the top of lakes, high O2, photosynthesis

has phytoplankton, fish and birds

metalimnion

rapid decrease in temperature, it is the thermocline between the other layers

hypolimnion

dark, cold, low O2 due to decomp of organic matter

bottom layer of lakes

thermal stratification/thermocline

summer and winter have thermally divided lakes , but the hypolimnion remains at 4 degrees while the surface temps are either warmer (28) or frozen (0)

in spring/water vertical mixing maintains uniform temps and it is 4 degrees throughout

oligotrophic

low nutrients (N, P), clear water, high O2, low primary productivity (plants)

different organisms will be adapted

eutrophic lakes

can be natural or cultural

increased N and P, decreased O2, more plants (primary productivity), dark water,

can cause algae bloom - even less O2 and even hypoxia

different organisms will be adapted

dystrophic

humic lakes

organic and humic acids, decreased pH (acidic), brown water, decreased primary productivity compared to oligo

different organisms will be adapted - but little survives here

wetlands

semi aquatic, changes with seasonality

two forms, bogs and fens

bogs

rainwater as the source → acidic, lumpy/patchy topography,

plant diversity - mosses and carnivorous plants, many shrubs and hardy tree species - requires specialized organisms

fens

groundwater reservoir as the source, variable pH - dependent on soil, flat topography

plant diversity: grasses, sedges, mosses, vascular plants

niche

environmental factors - abiotic and biotic factors, in which an organism can survive, grow and reproduce

this is abstract - any factors of interest can be apart

fundamental niche

physical conditions under which a species might live in the absence of interactions with other species → only abiotic factors are present

the full, idealized range of a species

realized niche

a subset of fundamental niche

environmental conditions under which a species might live when restricted by interactions with other species → includes biotic factors/competition

this is the real niche where a species resides

niche concept

Grinnell - abiotic factors, Elton - biotic factors

Hutchinsonian niche

n-dimensional hypervolume

when n is the number of environmental factors important to survival and reproduction, all the things which influence where something lives

for ex can include temp, pH, humidity and so on and so on

why characterize niche?

allows us to predict species range, where it travels, or how it moves during climate change

can be characterized by climate modelling (temp, precipitation, seasonality) and GIS

competitive exclusion principle

no two species can occupy the same realized niche, eventually one will out compete another

ex MacArthur’s warblers - timing or location on trees was different even tho they appeared to live on same trees

niche partitioning

when species in a community use resources (limiting factors) in different ways they are occupying different realized niches and coexists

ex cat tail species and water depth changes to limit overlaps