But such monitoring is not very effective, highly expensive, and by its very nature limited in time and space. It is therefore a highly unsatisfactory way of obtaining data for making reliable predictions of global changes. The great variability in the state of marine ecosystems in time and the vast expanses of the seas and oceans require a more systematic approach to their monitoring. One way of achieving this is by means of remote sensing techniques. Many attempts have already been made to use optical remote sensing methods with the aid of scanning radiometers mounted on board artificial satellites. Widely described in the literature (e.g. Gordon & Morel 1983,

Sathyendranath et al. 2000, Burenkov et al. 2001a,b, Arts 2003, Robinson 2010), these methods are based on the recording and analysis of the spectral properties of the light emerging from the sea water in comparison with the sunlight incident on the sea surface. In other check details words, they are based on the analysis of the EPZ-6438 colour of the sea in daylight, which depends on the absorption and scattering of light by the constituents of sea water and is an indirect indicator of their concentrations (including chlorophyll and other phytoplankton pigments). These satellite observations, backed up by in situ test measurements in the sea, enable

the efficient global monitoring of the state of the sea and the processes taking place in it, among them the photosynthesis of organic matter, the release of oxygen and eutrophication. The use

of remote sensing methods in studies of the sea is relatively simple only with respect to the waters of the central oceanic regions, i.e. Case 1 waters according to the optical classification (Morel & Prieur 1977). The great majority of substances affecting the colour of the sea in those regions are autogenic, that is, formed by the local ecosystem – photosynthesis by phytoplankton and the metabolism and decay of marine organisms. In consequence, the spectrum of the light emerging from these waters is correlated with the concentration of phytoplankton and its pigments, principally chlorophyll a, the commonest plant pigment. The concentration of chlorophyll a is therefore an index of phytoplankton concentration, HSP90 water trophicity and other ecological characteristics of a marine basin. Most of the algorithms now in common use for characterizing the state and functioning of marine ecosystems on the basis of remote sensing data are thus applicable to these waters: they utilize the correlations of their optical properties with the chlorophyll a concentration in surface waters and the correlation of this concentration with other properties of the aquatic environment (e.g. Platt et al. 1988, 1995, Sathyendranath et al. 1989, Platt & Sathyendranath 1993a, b, Antoine & Morel 1996, Antoine et al. 1996, Woźniak et al. 2003, Ficek et al. 2003, and the collective work by Campbell et al. 2002 and Carr et al. 2006).