Estimation of phytoplankton production from space: current status and future potential of satellite remote sensing

A new generation of ocean colour satellites is now operational, with freque nt observation of the global ocean. This paper reviews the potential to est imate marine primary production from satellite images. The procedures invol ved in retrieving estimates of phytoplankton biomass, as pigment concentrat ions, are discussed. Algorithms are applied to SeaWiFS ocean colour data to indicate seasonal variations in phytoplankton biomass in the Celtic Sea, o n the continental shelf to the south west of the UK. Algorithms to estimate primary production rates from chlorophyll concentration are compared and t he advantages and disadvantage discussed. The simplest algorithms utilise c orrelations between chlorophyll concentration and production rate and one e quation is used to estimate daily primary production rates for the western English Channel and Celtic Sea; these estimates compare favourably with pub lished values. Primary production for the central Celtic Sea in the period April to September inclusive is estimated from SeaWiFS data to be 102 gC m( -2) in 1998 and 93 gC m(-2) in 1999; published estimates, based on in situ incubations, are ca. 80 gC m(-2). The satellite data demonstrate large vari ations in primary production between 1998 and 1999, with a significant incr ease in late summer in 1998 which did not occur in 1999. Errors are quantif ied for the estimation of primary production from simple algorithms based o n satellite-derived chlorophyll concentration. These data show the potentia l to obtain better estimates of marine primary production than are possible with ship-based methods, with the ability to detect short-lived phytoplank ton blooms. In addition, the potential to estimate new production from sate llite data is discussed. (C) 2000 Elsevier Science BN. All rights reserved.