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limno round 2, in kurek's name we pray

Terms in this set (20)

3 internal sources of nutrients to freshwater systems
sediments and benthos, macrophytes and algae, food web alterations
as lakes, ponds, and wetlands age across time, their structure and finction changes. what is the key process that controls this?
sedimentation rate
a large, deep, thermally stratified lake near an urban area has algal blooms due to high nutrient loading, give 3 specific management appraoches
1) extract phospherous from waste water and sewage treatment
2) add chemical agents to bind
3) buffer littoral zone to trap nutrients
discuss important factors that determine recovery of aquatic invertebrates from past acidification
1) water quality - ph levels, calcoim levels, doc levels and uv penetration
2) community bariers - exterpation of fish, increased macroinvert communities
3) dispersal - increased survivorship for those dispersing to better waters
typical TP for oligotrophic lakes
1-10 ugL - 1
typical tp of mosotrophic lakes
10 - 25 ugl -1
typical tp of eutrophic lakes
130-200 ugl -1
obvious difference betreen eutrophic and oligotrophic lakes
oligotrophic lake has much lower TP because it has more O2
what might explain decreasing dissolved oxygen in a lake over time
1) increased decomposition
2)climate change altering stratification periods
where in the water column and during which season will dissolved oxygen be greatest
epilimnion in winter and summer, throughout in spring and fall
what 2 factors influencing oxygen solubility are most important to a shallow lake in winter and spring
salinity, bc increased salinity decreases oxygen availability.
temperature, bc increased temp decreases oxygen solubility.
3 factors important to maintaining plankton dominance
1) less grazing from zooplankton to create refugia
2) competition with algae and cyanobacteria
3) nutrients
differences between oligotrophic and eutrophic lakes
oligotrophic lakes a clearer, oligotrophic lakes have more O2 in hypolimnion but eutrophic lakes have O2 decreasing with depth, oligotrophic lakes have much less vegetation
how might you design a field study that looks to determine if alternating stable states are common in a remote shallow lake? what data would you expect to get if they are common?
i would look at measuring phospherous concentration in relation productivity, and how macrophyte biomass affects productivity (ie growth rate of algae). Also look at how macrophytes respond to increased nutrients. Of course all looked at over a long enough period of time to see the different states. and sample enough lakes for a reasonable sample size.
you would expect to see regime stable states between macrophyte and phytoplankton dominance under similar conditions.
why would an increase in piscivores favor a clear-water state in a shallow lake?
they would go down the food chain and eat the fish that eat the grazers that eat the small inverts that consume algae
3 mechanisms that can move phospherous from the sediments to the overlying water column
1) diffusion
2) wind
3) bioturbation
what is biovector transport and why is it a concern?
unidirectional transport of a pollutant into a new area done by an organism. an example is nitrogen, and it is a concern because it is hard to control.
why are P and N the most recognized limiting nutrients in freshwater?
relative to their concentration they have the highest demand, which limits growth. Needed to grow algae and macrophytes.
what are 3 characteristics of wetlands that distinguish from lakes.
1) wetlands filter more waste
2) wetlands are transitional areas, not necessarily any standing water
3) wetlands need vertical accretion
which characteristics make ponds and wetlands sensitive to environmental change.
their low water volume, very succeptible to evaporation. so as temperatures increase they lose more water and the pollutants become concentrated.
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