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A. Accornero et al.
the marine environment and are consequently influenced by a complex of physical (vertical and latéral transport, aggregation), Chemical (adsorption, flocculation, dissolution, oxidation) and biological (primary and secondary production,
microbial dégradation, egestion.grazing) factors. We hâve attempted to construct
a phenomenological process model to understand the behaviour of particulate
fluxes under external physical forcing, considering both the hydrological characteristics of the water masses and the hydrodynamic features in the investigated
area. At the same time we hâve tried to establish a coupling between biological
observations and physical data in order to test whether a relation exists between
the latter and microscopie observations.
Particulate matter sinking through the water column includes a large variety of
particles, with sédiment rates ranging from tens to hundreds of meters per day
[1]: phytoplankton and zooplankton débris, fecal pellets, molts, various kinds of
tests, remains and fecal material, aggregates of small particles, marine snow and
minerai matter. The quantitative évaluation of biogenic material and the measure
of its vertical transport rates through the water column are essential to describe
the functioning of an ecosystem and can significantly help to understand biogeochemical cycles on a wider scale.
The Ross Sea offers very interesting characteristics for the study of biogenic
particle fluxes, because it is the site of abundant primary production and signifiant biogenic accumulation [2-5]. In particular the ice edge zone seems to be of
key importance in the framework of the ecological [6] and biogeochemical
processes occurring in the Southern Océan, playing a major rôle in the annual
cycle of biogenic particle production [7-10]. Ice melting is responsible for the
création of local conditions of vertical stability which are essential for the starting of phytoplankton blooms in surface waters [11], which generally resuit in
substantial transport of biogenic particles to the deeper layers and sédiments.
Other features typical of the Ross Sea are the absence of sédiment input by fluvial System, terrigenous contributions being exclusively linked to glacial transport [13], and a relatively simple and confined océan circulation [13,14 and bibliography therein].
2 Materials and Methods
In the framework of the Italian National Programme for Antarctic Research, the
CLIMA Project (Climatic Long-term Interaction for the Mass balance in
Antarctica) planned for the First time in 1995 a sub-project for the study of particle fluxes in the Ross Sea. Three sites were selected for the deployment of mooring arrays equipped with time sériés sédiment traps and océanographie instrumentations from austral summer 1995 through January 1999. In particular, mooring site F (at the edge of the RIS) and H (in proximity of the continental shelf
break) were chosen in order to follow the fate of the Ice Shelf Waters (ISW) after
that an ISW core outflowing from below the RIS was localized at CTD stations
corresponding with the F mooring location (Fig. 1). The focus of this study is on
data from mooring site F (77°59'.998 S, 177°01'.623 W) during the deployment
period January 28,1995 - January 21,1996.
A. Accornero et al.
the marine environment and are consequently influenced by a complex of physical (vertical and latéral transport, aggregation), Chemical (adsorption, flocculation, dissolution, oxidation) and biological (primary and secondary production,
microbial dégradation, egestion.grazing) factors. We hâve attempted to construct
a phenomenological process model to understand the behaviour of particulate
fluxes under external physical forcing, considering both the hydrological characteristics of the water masses and the hydrodynamic features in the investigated
area. At the same time we hâve tried to establish a coupling between biological
observations and physical data in order to test whether a relation exists between
the latter and microscopie observations.
Particulate matter sinking through the water column includes a large variety of
particles, with sédiment rates ranging from tens to hundreds of meters per day
[1]: phytoplankton and zooplankton débris, fecal pellets, molts, various kinds of
tests, remains and fecal material, aggregates of small particles, marine snow and
minerai matter. The quantitative évaluation of biogenic material and the measure
of its vertical transport rates through the water column are essential to describe
the functioning of an ecosystem and can significantly help to understand biogeochemical cycles on a wider scale.
The Ross Sea offers very interesting characteristics for the study of biogenic
particle fluxes, because it is the site of abundant primary production and signifiant biogenic accumulation [2-5]. In particular the ice edge zone seems to be of
key importance in the framework of the ecological [6] and biogeochemical
processes occurring in the Southern Océan, playing a major rôle in the annual
cycle of biogenic particle production [7-10]. Ice melting is responsible for the
création of local conditions of vertical stability which are essential for the starting of phytoplankton blooms in surface waters [11], which generally resuit in
substantial transport of biogenic particles to the deeper layers and sédiments.
Other features typical of the Ross Sea are the absence of sédiment input by fluvial System, terrigenous contributions being exclusively linked to glacial transport [13], and a relatively simple and confined océan circulation [13,14 and bibliography therein].
2 Materials and Methods
In the framework of the Italian National Programme for Antarctic Research, the
CLIMA Project (Climatic Long-term Interaction for the Mass balance in
Antarctica) planned for the First time in 1995 a sub-project for the study of particle fluxes in the Ross Sea. Three sites were selected for the deployment of mooring arrays equipped with time sériés sédiment traps and océanographie instrumentations from austral summer 1995 through January 1999. In particular, mooring site F (at the edge of the RIS) and H (in proximity of the continental shelf
break) were chosen in order to follow the fate of the Ice Shelf Waters (ISW) after
that an ISW core outflowing from below the RIS was localized at CTD stations
corresponding with the F mooring location (Fig. 1). The focus of this study is on
data from mooring site F (77°59'.998 S, 177°01'.623 W) during the deployment
period January 28,1995 - January 21,1996.