Global warming and possible succeeding regional cooling have to be anticipated.

Meteorological variance leads to organic responses.
Flora and fauna change on various time-scales.
Permanent observation and documentation are necessary to detect, analyse, understand and hence predict the changes in ecological variance.

Sea Water temperatures change slower than air tamperatures.
Such conservative trigger provides a reliable orientation for marine organisms in their ontogenetic synchronisation.

The temporal succession of populations and their latitudinal distribution follow the thermal response profile.
This species-specific profile must be genetically determined.

Three ways may lead to the understanding of the rules of temperature controlled distribution of marine populations:

1. the laboratory analysis of thermal profiles in cultures and genetic investigations.

2. the description of the latitidunal distribution of populations as practised in palaeoceanography especially of foraminifera (Rutherford et al., 1999).

3. the continuous phenological observation along thermal gradients as practised at Helgoland Roads and suggested for the European marine biometeorological network EMBN (Greve et al., 2001)