Actinozoa
4
strictly marine, except for Heliozoa, and most species are pelagic. Some species
are as large as 2 mm, and colonies can reach a length of several meters.
Actinozoa ~Anthozoa.
action spectra ~Iight.
active continental margin ~(ontinental margin.
active transport process the mechanism by which living organisms are capable of
transporting solutes against a concentration gradient. Active transport
counteracting physical diffusion requires energy. It enables an organism to
maintain a lower concentration of sodium inside the cells and it enables the
cells to accumulate certain nutrients inside the cells at concentrations much
higher than extracellular concentrations. The exact mechanism of active
transport is still unknown, although many explanations have been proposed. Possibly a carrier molecule is involved which reacts chemically with
the solute to be actively transported. The compound formed is soluble in the
lipid portion of the membrane barrier and moves through the membrane,
against the existing concentration gradient, to the other side, where the
solute is released. The carrier molecule then diffuses back to pick up another molecule. Carrier molecules are probably proteins; each molecule to be
transported requires a specific carrier.
activity coefficient factor which, when multiplied by the molecular or ionic concentration, yields the chemically active mass of substance in solution. It is
the correction factor which adapts concentrations for thermodynamic calculations. The activity coefficient is obtained from physicochemical data.
adenosine triphosphate ~ATP.
adiabatic process a process is adiabatic when the system does not exchange heat
with the surroundings. According to the second law of thermodynamics the
work done in such a process by compression or expansion causes a change
in the enthalpy (~thermodynami(s). Adiabatic lifting of a volume of seawater
to the sea surface gives a decrease in enthalpy. The resulting temperature in
such a thought-experiment is called the potential temperature, symbol e, and
this parameter is used to characterize water masses that may move vertically,
as it is independent of such motions (conservative parameter).
adsorption ~sorption.
advection transport by the mean current, opposed to eddy diffusion (~eddy) or
spreading by dispersion.
4
strictly marine, except for Heliozoa, and most species are pelagic. Some species
are as large as 2 mm, and colonies can reach a length of several meters.
Actinozoa ~Anthozoa.
action spectra ~Iight.
active continental margin ~(ontinental margin.
active transport process the mechanism by which living organisms are capable of
transporting solutes against a concentration gradient. Active transport
counteracting physical diffusion requires energy. It enables an organism to
maintain a lower concentration of sodium inside the cells and it enables the
cells to accumulate certain nutrients inside the cells at concentrations much
higher than extracellular concentrations. The exact mechanism of active
transport is still unknown, although many explanations have been proposed. Possibly a carrier molecule is involved which reacts chemically with
the solute to be actively transported. The compound formed is soluble in the
lipid portion of the membrane barrier and moves through the membrane,
against the existing concentration gradient, to the other side, where the
solute is released. The carrier molecule then diffuses back to pick up another molecule. Carrier molecules are probably proteins; each molecule to be
transported requires a specific carrier.
activity coefficient factor which, when multiplied by the molecular or ionic concentration, yields the chemically active mass of substance in solution. It is
the correction factor which adapts concentrations for thermodynamic calculations. The activity coefficient is obtained from physicochemical data.
adenosine triphosphate ~ATP.
adiabatic process a process is adiabatic when the system does not exchange heat
with the surroundings. According to the second law of thermodynamics the
work done in such a process by compression or expansion causes a change
in the enthalpy (~thermodynami(s). Adiabatic lifting of a volume of seawater
to the sea surface gives a decrease in enthalpy. The resulting temperature in
such a thought-experiment is called the potential temperature, symbol e, and
this parameter is used to characterize water masses that may move vertically,
as it is independent of such motions (conservative parameter).
adsorption ~sorption.
advection transport by the mean current, opposed to eddy diffusion (~eddy) or
spreading by dispersion.