Photoadaptations of photosynthesis and carbon metabolism by phytoplankton from McMurdo Sound, Antarctica. 1. Species‐specific and community responses to reduced irradiances12

Abstract

Irradiance-dependent rates of photosynthesis and photosynthate labeling patterns were measured for phytoplankton in McMurdo Sound, Antarctica. Species-specific and traditional whole-water techniques were used to compare the physiological responses of algae collected in a high light environment at the ice edge and from a low light environment under the annual sea ice. There were differences among species within the same sample, for the same species isolated from high and low light environments, and when species-specific responses were compared with that of the natural assemblage. For algae collected beneath the sea ice, photosynthesis generally saturated at a lower irradiance, and the light-limited region of the P vs. I relationship had a steeper slope than for the same species collected at the ice edge. Low-light-adapted algae incorporated significantly less 14C into proteins and more into low molecular weight compounds and lipids than the same species isolated from a high light environment.Under conditions where reduced rates of protein synthesis were coupled with high rates of carbon uptake, the measurement of photosynthesis may not accurately reflect the physiological condition of the phytoplankton.

The effects of different environmental factors on the biochemical composition of particulate organic matter in Gwangyang Bay, South Korea

“…The biochemical pools of POM originating from phytoplankton are influenced by various environmental factors, such as temperature, salinity, nutrients, and light conditions (Morris et al, 1974;Smith and Morris, 1980;Rivkin and Voytek, 1987;Boëchat and Giani, 2008;Cuhel and Lean, 1987;Mock and Kroon, 2002;Khotimchenko and Yakoleva, 2005;Ventura et al, 2008;Sterner et al, 1997). In this study, significant relationships were found between environmental conditions and biochemical pools, especially PRT and LIP (Table 5).…”

Trophic dynamics in antarctic benthic communities. I. In situ ingestion of microalgae by Foraminifera and metazoan meiofauna

“…The patterns of biomass distribution and primary production by planktonic and benthic microalgae in McMurdo Sound are temporally and spatially variable (Bunt 1964, Dayton & Oliver 1977, Dayton et al 1986, Rivkin & Voytek 1987, Rivlun 1990. Primary production and the abundance of benthic infauna are reported to be significantly higher on the east side (e.g.…”

Primary production, calcification and macromolecular synthesis in a bloom of the coccolithophore Emiliania huxleyi in the North Sea

“…In this regard, it is worth noting that irradiance is a critical factor affecting not only the amount of carbon fixed into organic compounds, but also the biochemical composition of newly synthesized material (Cuhel et al 1984, Rivkin & Voytek 1987. Considering that phytoplankton growth rate is often more related to the synthesis of specific compounds rather than to total carbon fixation (Smith & Morris 1980, Hama et al 1988, knowledge of the relationship between irradiance and photosynthate partitioning may be useful to ascertain how the strategies of energy utilization by E. huxleyi-rich assemblages affect the dynamics of bloom formation and development.…”