TEMPERATURE, SALINITY, INSOLATION AND WASTING DISEASE OF EELGRASS (ZOSTERA-MARINA L) IN THE DUTCH WADDEN SEA IN THE 1930S

The possible role of temperature, salinity and insolation during the outbreak of 'wasting disease' of eelgrass (Zostera marina L.) in the 1930's was investigated for the Dutch Wadden Sea. An analysis of existing data indicates that salinity and temperature fluctuations played only a minor role. More important was the effect of insolation, as the early 1930's witnessed dull to very dull growing seasons. Daily sunshine figures of 1931 and 1932 were incorporated in an eelgrass growth simulation model. Simulation experiments predict that much of the then existing sublittoral eelgrass population would have succumbed, due to poor illumination conditions, even in the absence of the wasting disease. © 1990.