Vertical Distribution and Biochemical Composition
of Pico- and Microparticulate Organic Matter
in the Ross Sea (Antarctica)
M. Fabiano1, R. Danovaro2 and P. Povero1
1 Istituto di Scienze Ambientali Marine, Université di Genova, Corso Rainusso 14,
16038, S. Margherita L., Genova, Italy
2Cattedra di Ecologia, Facoltà di Scienze, Université di Ancona, Via Brecce Bianche,
60131 Ancona, Italy
Abstract
We studied the vertical distribution and biochemical composition of particulate
organic matter in seven Coastal stations located in Terra Nova Bay and in five
open-sea stations located in the Ross Sea (Antarctica) during summer 1989-90.
Protein, carbohydrate, lipid and ATP concentrations were estimated to assess the
quantitative rôle of labile organic fractions in the cycling of organic matter in the
water column and the processes related to particle dynamics. Particulate organic
matter was filtered through 0.2 and 2.0 m pore-size filters to discriminate two size
fractions: picoparticulate matter (particles between 0.2 and 2.0 m) and microparticulate matter (particles between 2.0 and 200 m). Significant quantitative and
qualitative différences between the pico- and microparticulate fraction were
observed. Total particulate suspended matter was mostly composed of microparticles, which accounted for two thirds of the total concentration. Similar results
were obtained for proteins, carbohydrates and lipids. By contrast, ATP concentrations were significantly higher in the picoparticulate fraction. Although most of
the picoparticulate matter was detrital (61.3%), this fraction contained the largest
proportion of living organisms (i.e. picoplankton), whereas the microparticulate
fraction was almost exclusively composed of organic détritus. Significant compositional différences between the two size-classes of particles were observed. The
microparticulate matter was dominated by proteins, whereas the picoparticulate
matter was mostly composed of carbohydrates. This may indicate a different origin of the two size-groups of particles.
1 Introduction
Particulate matter contains sizable stocks of picoplankton (i.e. 0.2 to 2.0 pm),
nanoplankton (2 to 20 pm) and microplankton (20 to 200 pm). During the last
decade picoplankton has been identified as one of the major biomass components
in the euphotic zone [1,2] and comprises a major fraction of particulate organic
carbon in oligotrophic océans [2]. Still, little is known about the relative significance of pico-, nano- and microplankton in the polar régions. Although the exact
nature and composition of particulate organic matter (POM) is of fundamental
of Pico- and Microparticulate Organic Matter
in the Ross Sea (Antarctica)
M. Fabiano1, R. Danovaro2 and P. Povero1
1 Istituto di Scienze Ambientali Marine, Université di Genova, Corso Rainusso 14,
16038, S. Margherita L., Genova, Italy
2Cattedra di Ecologia, Facoltà di Scienze, Université di Ancona, Via Brecce Bianche,
60131 Ancona, Italy
Abstract
We studied the vertical distribution and biochemical composition of particulate
organic matter in seven Coastal stations located in Terra Nova Bay and in five
open-sea stations located in the Ross Sea (Antarctica) during summer 1989-90.
Protein, carbohydrate, lipid and ATP concentrations were estimated to assess the
quantitative rôle of labile organic fractions in the cycling of organic matter in the
water column and the processes related to particle dynamics. Particulate organic
matter was filtered through 0.2 and 2.0 m pore-size filters to discriminate two size
fractions: picoparticulate matter (particles between 0.2 and 2.0 m) and microparticulate matter (particles between 2.0 and 200 m). Significant quantitative and
qualitative différences between the pico- and microparticulate fraction were
observed. Total particulate suspended matter was mostly composed of microparticles, which accounted for two thirds of the total concentration. Similar results
were obtained for proteins, carbohydrates and lipids. By contrast, ATP concentrations were significantly higher in the picoparticulate fraction. Although most of
the picoparticulate matter was detrital (61.3%), this fraction contained the largest
proportion of living organisms (i.e. picoplankton), whereas the microparticulate
fraction was almost exclusively composed of organic détritus. Significant compositional différences between the two size-classes of particles were observed. The
microparticulate matter was dominated by proteins, whereas the picoparticulate
matter was mostly composed of carbohydrates. This may indicate a different origin of the two size-groups of particles.
1 Introduction
Particulate matter contains sizable stocks of picoplankton (i.e. 0.2 to 2.0 pm),
nanoplankton (2 to 20 pm) and microplankton (20 to 200 pm). During the last
decade picoplankton has been identified as one of the major biomass components
in the euphotic zone [1,2] and comprises a major fraction of particulate organic
carbon in oligotrophic océans [2]. Still, little is known about the relative significance of pico-, nano- and microplankton in the polar régions. Although the exact
nature and composition of particulate organic matter (POM) is of fundamental