Freshwater Ecology Lecture Final Notes

Abiotic sulfur oxidation

reduced forms of sulfur combine with O2 for a net release of potential energy
spontaneously without biological mediation

Acute toxicity

poisoning with large pulses over short periods

Additive toxicity

when two toxicants together are more toxic than individually

Adhesion

water molecules sticking to other things

Advective transport

movement of materials by movement of parcels of water (as opposed to molecular
diffusion)

Aerobic

oxic (with oxygen)

Akinete

resting cell of cyanobacteria and some green algae, generally resistant to poor growth conditions

Algae

nonvascular organisms capable of oxygenic photosynthesis without sterile cells covering
gametangia

Alkalinity

the capacity of a solution to neutralize acid; the sum of all titratable bases; usually a function of
carbonate, bicarbonate, and hydroxide contents

Allelochemical

a chemical produced by one species that alters behavior or growth of another species

Allen curve

a plot of individual size vs. number of individuals in a cohort through time

Allochthonous

originating from outside the system; often refers to organic carbon

Alternative stable states

the idea that ecosystems can exist under different biotic and abiotic conditions

Amensalism

interspecific interaction in which one species is harmed and the other is not influenced (-/0)

Amictic

when a lake almost never mixes

Ammonia gas (NH3)

ammonium ion (NH4+) is converted to its toxic form, ammonia gas, at basic pH

Ammonium (NH4+)

an inorganic N compound; the ionic form of ammonia

Anaerobic

without oxygen; anoxic

Anoxic

without oxygen; anaerobic

Aquaculture

the farming of aquatic organisms

Aquifer

permeable deposit that can yield water by a well

Archaea

a domain of organisms, unicellular without organelles; one of three domains (super kingdoms) of
organisms; distinguished on the basis of biochemical and genetic differences from the Bacteria and
Eukarya

Attenuation coefficient

a value that indicates how rapidly light is absorbed

Autochthonous

originating within the system (e.g., organic carbon supplied by primary producers in the
system)