How will Benthic Foraminifera Respond to Warming and Changes in Productivity?: A Laboratory Culture Study on Cymbaloporetta plana

Abstract

ABSTRACTAnthropogenic activities are likely to cause global warming. Global warming will affect marine productivity and thus food availability for marine organisms. Both the seawater temperature and food availability affect benthic foraminifera, the most abundant marine calcareous microorganisms. Therefore, a laboratory culture experiment was conducted on Cymbaloporetta plana to understand the coupled effect of temperature (25°C, 27°C, 30°C) and food (102±5, 203±9, 305±14, 407±18, 508±23 diatom cells). At all temperatures, growth increased with increase in food. The specimens subjected to 27°C temperature attained the maximum growth and those subjected to 25°C were the smallest. All specimens fed with 508±23 cells reproduced, 0irrespective of temperature. Of all the specimens without food, 40% at 27°C and 20% at 25°C reproduced, whereas specimens subjected to 30°C did not reproduce. The 100% rate of reproduction at 27°C suggests that it is the optimum temperature for growth and reproduction. All the specimens at 30°C and without additional food, died, whereas at 25°C and 27°C, the mortality rate was 80% and 60%, respectively. The limited growth and reproduction with decreasing food clearly indicates that food availability also controls the growth and reproduction of shallow water benthic foraminifer C. plana. Therefore, warming coupled with decreasing productivity is likely to severely affect the growth and abundance of shallow water benthic foraminifera.