Picoplankton: Contribution to Phytoplankton Production in the Strait of Messina* |
| |
| Authors: | Giuseppe Magazz Vivia Bruni Augusto Piccione Trevor Platt Brian Irwin D V Subba Rao |
| |
| Institution: | Giuseppe Magazzù,Vivia Bruni,Augusto Piccione,Trevor Platt,Brian Irwin,D. V. Subba Rao |
| |
| Abstract: | Abstract. Biomass and primary production rates derived from photosynthesis-light curves on picoplankton (< 1 um fraction) and total phytoplankton were compared for the Strait of Messina. Picoplankton biomass ranged between 0.063 and 0.094 mg Chi a m-5 and accounted for 56–63 % of the total. Total primary production rates were between 0.22 and 1.56 mg C-m-2-h-1 of which the picoplankton contribution ranged from 24 to 43%. In this turbulent nearshore environment, the contribution of picoplankton to total phytoplankton production is considerably less than in calmer open-ocean waters. Carbon assimilation numbers (Pmb), the initial slope (a), adaptation parameter (Ik), optimal irradiance (Im) and compensation intensity (Lm,) for the picoplankton were lower than for the > 1 μm fraction. Fitted respiration (RmB) for the picoplankton was, however, on the average higher (10.3 % of PmB) than for the > 1 μrn fraction (6.6 %). Assimilation numbers for the > 1 μm fraction in the southern stations were of higher magnitude (8.5–12.0 mg C mg Chi a-1 h-1) than in the northern station, possibly due to the impact of upwelled water flowing southward along the Sicilian coast. |
| |
| Keywords: | Phytoplankton picoplankton photosynthesis primary production size fractionation Mé diterranean Sea |
|
|
