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46 terms

Freshwater

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epilimnion
top layer of warm water in a stratified lake or other body of water.
metalimnion
middle layer in a stratified lake or other body of water where temperature changes most rapidly with depth, also known as the thermocline.
hypolimnion
bottom layer in a stratified lake or other body of water where little light penetrates.
warm monomictic
the majority of NZ's lakes are this stratification type, experiencing only one stratification even per year
catchment, morphology
two factors physical, chemical, and biological conditions in a lake are determined by
limnetic
foodchain occuring in the sunlit surface waters
littoral
foodchain occuring in shallow water close to the shore
detrital
foodchain centered around the decomposition of organic matter
phytoplankton, benthic macrophytes
in lakes, primary production is dominated by _________________; in shallow lakes ___________________ also play a key role in primary production
sediment production zone
river zone in which channel slope is steep, whose bottom is rocky, and which acts as the major source of water and sediment. AKA erosion zone.
sediment transfer zone
river zone in which gradient is reduced, which has a sandy or gravelly bottom, and which experiences little net gain or loss in sediment
sediment deposition zone
river zone where the river deposits it's sediment load and which is silty bottomed; typically in an estuary or delta
phytoplankton, epiphytic microalgae, terrestrial detritus, coarse particulate organic matter, fine particulate organic matter, macrophytes
*in rivers and streams, _______________ are usually negligible in primary production; ________________ are more important. ________________ is the most important source, in the form of _____________________ upstream and ________________________ downstream. _________________ are historically unimportant in New Zealand because streams are generally heavily shaded.
zooplankton, benthos
with regards to consumers in rivers and streams, __________________ are usually rare or absent; __________________ are dominant.
hydrology, nutrients
critical influences on wetlands are __________________ and ____________________.
fringe wetlands, aquatic marginal vegetation wetlands
___________________ are wetlands that experience continuous or very frequent connection to the parent water body, belonging to the larger category of wetlands, __________________, which are are created by open water bodies.
flood wetlands, aquatic marginal vegetation wetlands
___________________ are wetlands that connected to the parent water body only during flood periods, belonging to the larger category of wetlands, __________________, which are are created by open water bodies.
fens, mires
__________________ are wetlands whose water is primarily below ground, which are nutrient rich, and are fed by overland flow or groundwater. They belong to the larger category of wetlands, ________________, which are permanently waterlogged, independent of parent open water body.
bogs, mires
__________________ are wetlands whose water is primarily above ground, which are nutrient poor (and therefore experience low productivity) and are fed by precipitation. They belong to the larger category of wetlands, ________________, which are permanently waterlogged, independent of parent open water body.
aquifer
sediment that stores and yields groundwater
hyporheic zone
zone of saturated sediments under river beds
allochthonous
*groundwater fauna communities are driven by __________________ food sources (e.g. detritus).
stygobites
species living entirely in true groundwater habitats
eutrophication
*freshwater management issue that is the process by which a body of water becomes too rich in dissolved nutrients, leading to plant growth that depletes oxygen.
channelization, sedimentation, removal of riparian vegetation
*three examples of changes to streams
changes in species composition
in New Zealand, the brown trout is a prime example of this management issue.
estuary
a partly enclosed tidal inlet of the sea, in which sea water and river water mix to some degree.
fjord
a drowned glacial valley; narrow with rocky sides and bottom. Because they are steep-sided, the intertidal zone is biologically insignificant.
sectionally homogenous estuaries
estuaries in which river flow is minor, and the tides are dominant; any vertical salinity gradient is eliminated by intense turbulent mixing (the water column is fully mixed). Most of New Zealand's estuaries are this type of estuary.
salt-wedge estuaries
estuaries in which river flow is dominant and tidal inputs are minor; denser sea water intrudes up estuary as wedge-shaped layer under freshwater.
fluvial, tidal
the ____________:______________ ratio is a critical factor in determining estuary type.
primary productivity
rate at which organic matter is formed
bar-built estuary
an estuary which occurs where river flow is too weak to keep the mouth fully open.
productive, shallow, nutrient sinks, poor, dynamic, too geologically transient
*estuaries are usually _______________ (productive/unproductive) because they are ______________ and _______________ and species ________________ (poor/rich) because they are highly _______________ and ____________________, preventing the evolution of many specialists.
autochthonous
input, such as nutrients, into a system from within that system. In estuaries this can be from phytoplankton and benthic marine algae and macrophytes and macrophyte detritus.
allochthonous
input, such as nutrients, into a system from outside of that system. In estuaries this can be from upstream phytoplankton or detritus from the rivers and sea.
sites for human habitation, alteration of physiography, water quality, changes in species composition and abundance
human impacts on estuaries (4)
groundwater
*at 91%, what is the highest source of liquid freshwater on our planet?
deep, wind
*________________ lakes with little ________________ are most likely to experience seasonal stratification.
particles in the water
*suspension feeders usually eat ____________________.
glacial
*most of nz's lakes are this type:
decrease, decrease, increase
*when trout are introduced to nz streams, galaxiid fishes ___________ in number, invertebrates _____________ in number, algae ______________ in abundance
terrestrial origin of water
*What is usually the major determinant of water chemistry in streams and rivers?
detritus on the lakebed
*Deposit feeders eat:
geologically short-lived
*Why are estuaries thought to contain low species diversity?
small catchment areas of estuaries lead to low freshwater input
*Hydrological and geomorphological processes in New Zealand estuaries are marine-dominated because: