Fundamentals of Biological Life

MSCI 340

Autotroph

an organism that converts inorganic nutrients into complex organic substances; a primary producer

Chemoautotroph

use chemical energy to fuel reactions

Heterotroph

an organism that obtains nutrients from consuming complex organic substances (a predator)

Saprotroph

an organism that obtains nutrients from non-living (decaying) organic matter (detritovore)

Biological Pump

sequesters carbon into deep ocean via sinking of organic detritus, death of organisms, and direct transport by swimmers. It is the long-term sequestration of carbon from the atmosphere to the deep ocean via biological processes.

Plankton

small organisms drifting in the water column

Phytoplankton

Photosynthetic algae and cyanobacteria that drift in the ocean

Picoplankton

floating organisms, 0.2 - 2.0 μm in size

Femtoplankton

<0.2 μm, marine viruses

DOC/DOM

Decaying Organic Matter - organic compounds that pass through a filter (usually with a pore size between 0.2 and 0.7 µm). It consists of relatively simple organic compounds, such as sugars, amino acids, and humic substances

POC/POM

Particulate Organic Matter - organic matter that is retained on the filter (too large to pass through). It includes organisms, such as plankton, and detritus.

Marine Snow

a continuous shower of mostly organic detritus—dead plankton, fecal matter, and mucus—falling from surface waters to the deep ocean, appearing as white, fluffy flakes

Recalcitrant DOM

the stable, complex fraction of organic carbon in aquatic ecosystems that resists rapid biological degradation and microbial decomposition

Viral Shunt

marine ecological process where viruses infect and lyse (burst) microorganisms like bacteria and phytoplankton, converting particulate organic matter (POM) into dissolved organic matter (DOM)