Ml. Wells et Ed. Goldberg, THE DISTRIBUTION OF COLLOIDS IN THE NORTH-ATLANTIC AND SOUTHERN OCEANS, Limnology and oceanography, 39(2), 1994, pp. 286-302
The concentrations and size distributions of small (<200 nm) colloids
were measured at three stations in the North Atlantic and two stations
in the Southern Ocean. The stations were chosen to cover a range of o
ceanographically distinct regimes, from highly productive nearshore en
vironments to oligotrophic open-ocean waters. Colloid number concentra
tions decreased appreciably from the surface to approximately 150-m de
pth at three of these stations. Concentrations in deep waters of the N
orth Atlantic were high but erratic, suggesting that colloid abundance
is regulated by rapid rates of reactions. The colloids were mainly or
ganic and their immediate sources appear to include both autotrophic a
nd heterotrophic activity as well as sediment resuspension. Transmissi
on electron microscope examination of colloid size distributions and m
orphology indicates that aggregation is the principal removal mechanis
m for these colloids. Evidence from the cumulative size spectra of sma
ll colloids indicates that colloid aggregation is most intense in vert
ically delineated zones near the surface, around the main thermocline
(approximately 1,000-1,500 m), and in bottom waters. These findings sh
ow that the marine colloidal state is abundant but discontinuous in bo
th space and time throughout a wide range of oceanographic environment
s.