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M. Fabiano et al.
importance to our understanding of the food web (including the microbial loop),
it cannot be easily obtained. One of the major problems is distinguishing and
quantifying different components. Microscopie analysis can yield detailed information, but it is slow, and thus often not suitable for large number of samples
taken during the course of an expédition. Accurate and complété characterizations of particulate matter from a Chemical point of view are extremely difficult.
Simple analyses of elemental composition do not sufficiently characterize the
processes associated with the particle dynamics in the water column and their
availability to consumers. In contrast, the biochemical analysis of the organic particles, applied to different size classes, might provide new insights into the origin,
dynamics and fate of organic particles in the sea [3].
Although a relatively large amount of data on the elemental composition of
suspended matter in the Ross Sea is available [4-8], little is known about its biochemical composition [9-12]. Lipid, protein and carbohydrate contents of particles were found to provide useful information about their origin and availability
to consumers [3], and ATP content provides information on the living component
of the organic carbon [13].
Our principal objectives were to assess, using a biochemical approach, the different particle sizes as a measure of the food potentially available for plankton. The
biochemical composition provides indications of the nature and origin of the particles. We measured the ambient concentrations of two different size fractions of
the particulate organic matter: picoparticulate organic matter (0.2 to 2.0 pm) and
microparticulate organic matter (2.0 to 200 pm) in order to: (1) identify différences
in the biochemical composition (carbohydrate, protein, lipid and ATP) among different size fractions; (2) provide new information on the changes in particle composition with water depth and (3) compare the composition and the relative significance of these particles in Coastal (Terra Nova Bay) and open sea stations.
2 Materials and Methods
2.1 Sampling Area
Twelve stations were sampled during the Second Italian Océanographie
Expédition in the Ross Sea, on board the R/V “Cariboo”, between December 5,
1989, and January 6,1990, and using the R/V “Malippo”, between January 13 and
February 2. The sampling schedule included the following stations: 17,19 and 21
(in the southeastern région of the Ross Sea), 23 and 25 (along 75° S in the southwestern area of the Ross Sea) and 2,3,7,8,12,16 and 17 located in the coastal area
of Terra Nova Bay (Fig. 1).
2.2 Hydrology
At each station data on température and salinity were collected, using a Neil
Brown Mark III CTD System [14] during the “Cariboo” cruise and using a
Meerestechnik KMS-90 System during the “Malippo” cruise [15]. Vertical attenu-
M. Fabiano et al.
importance to our understanding of the food web (including the microbial loop),
it cannot be easily obtained. One of the major problems is distinguishing and
quantifying different components. Microscopie analysis can yield detailed information, but it is slow, and thus often not suitable for large number of samples
taken during the course of an expédition. Accurate and complété characterizations of particulate matter from a Chemical point of view are extremely difficult.
Simple analyses of elemental composition do not sufficiently characterize the
processes associated with the particle dynamics in the water column and their
availability to consumers. In contrast, the biochemical analysis of the organic particles, applied to different size classes, might provide new insights into the origin,
dynamics and fate of organic particles in the sea [3].
Although a relatively large amount of data on the elemental composition of
suspended matter in the Ross Sea is available [4-8], little is known about its biochemical composition [9-12]. Lipid, protein and carbohydrate contents of particles were found to provide useful information about their origin and availability
to consumers [3], and ATP content provides information on the living component
of the organic carbon [13].
Our principal objectives were to assess, using a biochemical approach, the different particle sizes as a measure of the food potentially available for plankton. The
biochemical composition provides indications of the nature and origin of the particles. We measured the ambient concentrations of two different size fractions of
the particulate organic matter: picoparticulate organic matter (0.2 to 2.0 pm) and
microparticulate organic matter (2.0 to 200 pm) in order to: (1) identify différences
in the biochemical composition (carbohydrate, protein, lipid and ATP) among different size fractions; (2) provide new information on the changes in particle composition with water depth and (3) compare the composition and the relative significance of these particles in Coastal (Terra Nova Bay) and open sea stations.
2 Materials and Methods
2.1 Sampling Area
Twelve stations were sampled during the Second Italian Océanographie
Expédition in the Ross Sea, on board the R/V “Cariboo”, between December 5,
1989, and January 6,1990, and using the R/V “Malippo”, between January 13 and
February 2. The sampling schedule included the following stations: 17,19 and 21
(in the southeastern région of the Ross Sea), 23 and 25 (along 75° S in the southwestern area of the Ross Sea) and 2,3,7,8,12,16 and 17 located in the coastal area
of Terra Nova Bay (Fig. 1).
2.2 Hydrology
At each station data on température and salinity were collected, using a Neil
Brown Mark III CTD System [14] during the “Cariboo” cruise and using a
Meerestechnik KMS-90 System during the “Malippo” cruise [15]. Vertical attenu-