Perpetual adaptation in a perpetually changing environment as a survival strategy of plants: a case study in foraminifers concerning coral reef bleaching

Coral reef bleaching is a global phenomenon poorly understood today. We inv estigated during 7 d the photosynthetic behaviour of symbionts of coral ree f and temperate foraminifers in hospite, by means of the JIP-test. By this screening test the fast fluorescence rise O-J-I-P, measured by a Plant Effi ciency Analyser (PEA) with 10 mu s time resolution and 12 bit signal resolu tion, was analysed. II informs about the structure and function of photosys tem 2 being at different physiological states established by adaptation to different irradiance and temperature. The test needs a measuring time in vi vo of only 1 to 5 s, and thus many samples can be analysed. The measurement s can be done continuously even on a single cell in a test tube or on the r eef. The reef foraminifers tested here were Amphistegina and Amphisorus, fr eshly collected in Mauritius. As a temperate foraminifer, Sorites from the Mediterranean Sea was tested. The cells are very sensitive to slight temper ature changes (25 to 32 degrees C). The comparison showed that the more the foraminifers live in an environment with constant temperature the less the y are able to respond to temperature changes and, thus, the less they can a dapt. Rising the temperature increases in general the sensitivity to differ ent stress factors, such as high irradiance, pH, CO2, etc. After the test s eries, the cells recovered fully and were kept in an aquarium for long time observation.