THE NEAR-SURFACE LAYER OF THE OCEAN
where P is the kinematic molecular diffusion coefficient of gas, 0
G is the
flux of property C at the air-sea interface,
0
w
C C C
'
is the is the
ensemble averaged air-sea gas concentration difference in property C across
the diffusion sublayer, 0
C and b
C are the averaged concentrations of
property C at the water surface and in the bulk (mixed layer) water
respectively. Taking into account (1.50) we obtain the following relationship
connecting the gas exchange coefficient and the thickness of the diffusion
sublayer:
/ K
P
P
G
P
.
(2.5)
2.1.4 Sea surface microlayer ecosystem
The sea surface is a highly productive, metabolically active interface
(Hardy et al., 1997). Due to extreme conditions at the air-sea interface, the
sea surface is believed to be the place where life on the Planet originated (a
competing theory is that of extraterrestrial origin for life on the Earth).
Phytoplankton in the water column produces an abundance of particulate
and dissolved organic material, some of which is transported to the surface
either passively by buoyancy or actively by upwelling, turbulence, and
bubble transport. The natural and anthropogenic compounds deposited from
the atmosphere often accumulate on the ocean surface in relatively high
concentrations compared to those in the water column. The abundance of
organic matter at the sea surface provides a substrate for the growth of the
surface-dwelling organisms, the marine neuston, which inhabits the sea
surface microlayer (Zaytsev, 1997).
Neuston realm is a vast habitat. The distinctive physical and chemical
characteristics of the sea surface can explain a highly diverse and abundant
assemblage of species in the microlayer. Organisms from most major
divisions of the plant and animal kingdoms either live or reproduce or feed
in the surface layers (Zaitsev, 1971). Many of these species are of
commercial and ecological importance. The microneuston, which may be
involved in biogeochemical cycling, and neustonic eggs and larvae of
commercially important fish and shellfish, are of particular interest.
Figure 2-4 shows Hardy’s (1982) conceptual model of the sea surface
microlayer ecosystem. Permanent inhabitants of the surface layer often reach
much higher densities than similar organisms found in subsurface waters.
There are also numerous temporary inhabitants of the neuston. These are
particularly the eggs and larvae of a great number of fish and invertebrate
species. The latter utilize the surface during a portion of their embryonic and
larval development. Some neuston can remain in the microlayer until
74
where P is the kinematic molecular diffusion coefficient of gas, 0
G is the
flux of property C at the air-sea interface,
0
w
C C C
'
is the is the
ensemble averaged air-sea gas concentration difference in property C across
the diffusion sublayer, 0
C and b
C are the averaged concentrations of
property C at the water surface and in the bulk (mixed layer) water
respectively. Taking into account (1.50) we obtain the following relationship
connecting the gas exchange coefficient and the thickness of the diffusion
sublayer:
/ K
P
P
G
P
.
(2.5)
2.1.4 Sea surface microlayer ecosystem
The sea surface is a highly productive, metabolically active interface
(Hardy et al., 1997). Due to extreme conditions at the air-sea interface, the
sea surface is believed to be the place where life on the Planet originated (a
competing theory is that of extraterrestrial origin for life on the Earth).
Phytoplankton in the water column produces an abundance of particulate
and dissolved organic material, some of which is transported to the surface
either passively by buoyancy or actively by upwelling, turbulence, and
bubble transport. The natural and anthropogenic compounds deposited from
the atmosphere often accumulate on the ocean surface in relatively high
concentrations compared to those in the water column. The abundance of
organic matter at the sea surface provides a substrate for the growth of the
surface-dwelling organisms, the marine neuston, which inhabits the sea
surface microlayer (Zaytsev, 1997).
Neuston realm is a vast habitat. The distinctive physical and chemical
characteristics of the sea surface can explain a highly diverse and abundant
assemblage of species in the microlayer. Organisms from most major
divisions of the plant and animal kingdoms either live or reproduce or feed
in the surface layers (Zaitsev, 1971). Many of these species are of
commercial and ecological importance. The microneuston, which may be
involved in biogeochemical cycling, and neustonic eggs and larvae of
commercially important fish and shellfish, are of particular interest.
Figure 2-4 shows Hardy’s (1982) conceptual model of the sea surface
microlayer ecosystem. Permanent inhabitants of the surface layer often reach
much higher densities than similar organisms found in subsurface waters.
There are also numerous temporary inhabitants of the neuston. These are
particularly the eggs and larvae of a great number of fish and invertebrate
species. The latter utilize the surface during a portion of their embryonic and
larval development. Some neuston can remain in the microlayer until
74