2001- Math006 module of the Extended Science Programme.

The impact of climatic changes on biological populations and the modelling of marine ecosystems. During the last three decades the variations observed in several ecosystems around the British Isles have tracked quite closely the north-south movements of the Gulf Stream close to the US coast. I have been exploring the atmospheric processes responsible for this association in a number of papers (including three in Nature, see also our web-site: www.pml.ac.uk/gulfstream). At the root of the connection is the North Atlantic Oscillation (NAO), the dominant pattern of climatic variation in the region.

In a collaboration with Avijit Gangopadhyay at the University of Massachusetts, I have developed a simple numerical model demonstrating how the Gulf Stream responds to the NAO by integrating changes over several years. Professor Phil Dyke and I are together working on improving the physics in this model. Recently, Avijit and I have been employing spectral analysis to examine the characteristic time-scales of the Gulf Stream and the NAO.

In order to determine why the Gulf Stream signal appears in the biological time-series, rather than the much stronger NAO signal, Icarus Allen at Plymouth Marine Laboratory and I have been carrying out experiments with the European Regional Seas Ecosystem Model (ERSEM). We have shown that the model preferentially extracts the Gulf Stream signal from thirty years of meteorological observations by combining the effects of different weather variables. We are presently repeating these calculations using 100 years of totally synthetic data from the Hadley Centre's coupled ocean-atmosphere model HadCM3. This is showing that that the observation is not some chance occurrence of recent decades but is a characteristic feature of dynamics of the climate system.

TAYLOR, A.H. 1995. North-south shifts of the Gulf Stream and their climatic connection with the abundance of zooplankton in the UK and its surrounding seas. ICES J. Mar. Sci., 52, 711-721.

GEORGE, D.G. and TAYLOR, A.H. (1995) UK lake plankton and the Gulf Stream. Nature, 378, 139.

TAYLOR, A.H., JORDAN, M.B. and STEPHENS, J.A. (1998) Northward shifts of the Gulf Stream following ENSO events. Nature, 393, 638.

TAYLOR, A.H. and GANGOPADHYAY, A. (2001) A simple model of interannual displacements of the Gulf Stream. J. Geophys. Res., 106(C7), 13849-13860.

LEFEVRE, N. and TAYLOR, A.H. (2002) Estimating pCO2 from sea surface temperatures in the Atlantic gyres. Deep-Sea Res., 49, 539-554.

TAYLOR, A.H. 2002 North Atlantic climatic signals and the plankton of the European Continental Shelf, Large Marine Ecosystems of the North Atlantic: Changing States and Sustainability ed. by K. Sherman and H.R. Skjoldal., 3-26.

TAYLOR, A.H. , ALLEN, J.I. and CLARK, P.A. 2002 Extraction of a weak climatic signal by an ecosystem. Nature, 416, 629-632.

ARCHER, S.D., GILBERT, F.J., NIGHTINGALE, P.D., ZUBKOV, M.V., TAYLOR, A.H., SMITH, Q.C. and BURKILL, P.H. 2002. Transformation of dimethylsulphoniopropionate to dimethyl sulphide during summer in the North Sea with examination of key processes via a modelling approach. Deep Sea Research II, 49, 3067-3101.

LEFEVRE, N., TAYLOR, A.H., GILBERT, F.J. and GEIDER, R.J. 2003. Modelling carbon-to-nitrogen and carbon-to-chlorophyll a ratios in the ocean at low latitudes: evaluation of the role of physiological plasticity. Limnol. and Oceanogr., 48, issue 5.

DEARMAN, J.R., TAYLOR, A.H. and DAVIDSON, K. 2003. The influence of autotroph model complexity on simulations of microbial communities in marine mesocosms. Mar. Ecol. Prog. Ser., 230, 13-28.