Ecology Final (test 4)
Globally, most energy flow is through:

o    poikilotherms

Unlike energy flow through ecosystems, the elemental constituents of biomass:

o    are recycled

Microbial enrichment refers to:

o the release of dissolved nutrients from POM by microorganisms breaking it down

How can a P/R ratio (carbon sink/carbon source) indicate disturbance in natural communities?

o    pulses of organic matter can shift the ratio into a heterotrophic succession

o    early successional stages resulting from “repair” of forest gaps are areas of higher production than respiration

o    stable climax communities at equilibrium for biomass and energy dynamics tend to have a P/R ratio of  1

The terms Pioneer and Climax species have been used by botanists to describe:

q  r-selected species (pioneer) and K selected species (climax) based on growth dynamics and competitive ability. 

GPP – NPP = 

qplant respiration

A P/R ratio is indicative of which of the following:

qwhether or not a community is at steady state

qwhether or not a community is detritus based

qwhether a community is undergoing succession or is at climax

A P/B ratio provides an indication of:

o production as a fraction of biomass respired

The difference between regional natural NPP and human modified landscape production (agriculture, lawns,asphalt, concrete, buildings, etc.) is called:

o  coopted and missing production

Which of the following is listed in order of increasing assimilation efficiency:

o detritivores, herbivores, carnivores 

Which of the following factors contribute to determining the half-life of detritus in the 0 horizon?

qEcotone gradients



Mineralization and Immobilization refer to:

A) The change in the net flux of nutrients as detritus decomposes (me)

What are the three dominant greenhouse gases

o none of these (CO2 NO2 CH4)

Energy that contributes to NPP but is not directly captured as chemical potential energy in biomass is called:

o energy subsidy

In terms of sources of nutrient pollution, which has a greater impact?

q Non-point sources

TMDL” stands for:

q Total Maximum Daily Load

Three broad categories that were presented as types of environmental impacts from man’s activities are:

q  overloads with biodegradables, alteration of abiotic conditions, addition of novel synthetic organics

What does “Assimilative Capacity” mean?

q  Ability to utilize or absorb a substance (The ability of a body of water to cleanse itself; its capacity to receive waste waters or toxic materials without deleterious effects and without damage to aquatic life)

What is the origin of the N coming down with the rainfall?

q  Onshore combustion of fossil fuels

Why is rainfall a problem for some sewage treatment plants?

q  some older cities have combined storm water and sewer systems 

Why isn’t sewage sludge used more widely as compost?

q  sludge may be contaminated with metals and synthetic chemicals.

q  the attitude represented by: “You’re not putting that stuff on my vegetables!”

What are the potential uses of sewage treatment plant effluent?

q  Irrigation

.  The goal of secondary sewage treatment is:
biological treatment
Approximately what fraction of municipal solid waste going to landfills is biodegradable or recyclable?

q  >70%

Why don’t organic materials degrade in landfills?

q  They are anerobic

Why is mercury contamination such a problem in Florida?

q  There’s lots of sulfate reducing bacteria

Individual land/homeowners

q  none of these


q  results in increased toxicant loads if they are retained when assimilated biomass is respired.

What would you predict to be the effect of a toxic pollutant on growth efficiency?

q  energy expended in repair from toxicant damage would decrease growth efficiency

A tertiary stage of sewage treatment involves:

q  None of these  (nutrient removal)

.  If bacteria like to eat oil, why are oil spills a problem?

q  If it exceeds the assimilative capacity of the system, it creates a smothering overload

q  When the labile stuff is gone, the refractory stuff is toxic

q  If it can find anaerobic space, it can’t be oxidized to CO2

PCB stands for:

q  none of these (polychlorinated biphenyls)


q  are hydrophobic

q  are toxic

q  come from coal tar

q  come from crude oil

What is PAN?

q  Peroxacetyl Nitrate

Combustion of fossils fuels affects which of the following:

q  Air quality

q  Nitrogen loading in waterways

q  Mercury loading of waterways

q  Percent base saturation of soils

In order, which fuel provides the most energy return


The greenhouse effect

o is an environmental cause with no real substance

.  Atmospheric carbon dioxide has increased approximately how much in the past 150 years

o 10 percent (it should be going up 2-3ppm per year, but instead is going up 1ppm)

Why is phosphate so naturally limiting?

It is very insoluble

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