Primary productivity of the Palmer Long Term Ecological Research area and the Southern Ocean

A major objective of the Palmer Long Term Ecological Research (Palmer LTER) project is to obtain a comprehensive understanding of the various componen ts of the Antarctic marine ecosystem. Phytoplankton production plays a key role in this so-called high nutrient, low chlorophyll environment, and fact ors that regulate production include those that control cell growth (Light, temperature, and nutrients) and those that control cell accumulation rate and hence population growth (water column stability, grazing, and sinking). Sea ice mediates several of these factors and frequently conditions the wa ter column for a spring bloom which is characterized by a pulse of producti on restricted in both time and space. This study models the spatial and tem poral variability of primary production within the Palmer LTER area west of the Antarctic Peninsula and discusses this production in the context of hi storical data for the Southern Ocean. Primary production for the Southern O cean and the Palmer LTER area have been computed using both light-pigment p roduction models [Smith, R.C., Bidigare, R.R., Prezelin, B.B., Baker, K.S., Brooks, J.M., 1987. Optical characterization of primary productivity acros s a coastal front. Mar. Biol. (96), 575-591; Bidigare, R.R., Smith, R.C., B aker, K.S., Marra, J., 1987. Oceanic primary production estimates from meas urements of spectral irradiance and pigment concentrations. Global Biogeoch em. Cycles (1), 171-186; Morel, A., Berthon, J.F., 1989. Surface pigments, algal biomass profiles and potential production of the euphotic layer-relat ionships reinvestigated in view of remote-sensing applications. Limnol. Oce anogr. (34), 1545-1562] and an ice edge production model [Nelson, D.M., Smi th, W.O., 1986. Phytoplankton bloom dynamics of the western Ross Sea ice ed ge: II. Mesoscale cycling of nitrogen and silicon. Deep-Sea Res. (33), 1389 -1412; Wilson, D.L., Smith, W.O., Nelson, D.M., 1986. Phytoplankton bloom d ynamics of the Western Ross Sea ice edge: I. primary productivity and speci es-specific production. Deep-Sea Res., 33, 1375-1387; Smith, W.O., Nelson, D.M., 1986. Importance of ice edge phytoplankton production in the Southern Ocean. BioScience (36), 251-257]. Chlorophyll concentrations, total photos ynthetically available radiation (PAR) and sea ice concentrations were deri ved from satellite data. These same parameters, in addition to hydrodynamic conditions, have also been determined from shipboard and Palmer Station ob servations during the LTER program. Model results are compared, sensitivity studies evaluated, and productivity of the Palmer LTER region is discussed in terms of its space time distribution, seasonal and interannual variabil ity, and overall contribution to the marine ecology of the Southern Ocean.