Effects of Temperature Change on Activity and Survival of Selected Tropical Ophiuroidea (Ophiomastix annulosa, Ophiarachna incrassata, Ophiocoma cf. dentata) and Asteroidea (Fromia milleporella)

Abstract

It is widely accepted that global warming and climate change are have occured over the past 30 years and it changed the temperature in the air and in marine waters. Organisms in all areas, in this case in marine, are quite sensitive to temperature changes. They have a certain capacity to cope with the changing environment. If these organisms cannot adapt to environmental changes, they could die. The main stress factor that was being used in this research is temperature, and salinity as another stressor for comparison. Using selected tropical Echinoderms, the thermal and salinity capacity of these organisms was tested through simulation of environmental changes in lab. The objectives of this study are to identify the temperature limit (in comparison to lower salinity limit), activity, and assess the impact of temperature and salinity stress for selected tropical Ophiuroidea (Ophiomastix annulosa, Ophiarachna incrassata, Ophiocoma cf. dentata) and Asteroidea (Fromia milleporella). The velocity of changes (increase or decrease) in temperature might also affect the survival of the organisms. Different velocities (hourly and daily)of temperature change were investigated to see if there was any difference in temperature limit (the organisms’ capacity and adaptation) and the effects to these organisms (Ophiuroidea and Asteroidea). This experiment was conducted in Marine Habitat Lab, Faculty of Fisheries and Marine Sciences, Bogor Agricultural University (IPB); from December 2010-November 2011. The upper thermal limit (hourly increase) for Ophiomastix annulosa, Ophiarachna incrassata, Ophiocoma cf. dentata, and Fromia milleporella was 36.5 0C and 37 0C, 37.2 0C, 40.5 0C, and 35.8 0C and 35.0 0C (respectively). The upper thermal limit (daily increase) for Ophiomastix annulosa, Ophiarachna incrassata, and Fromia milleporella was 35.0 0C, 34.0 0C, and 33.0 0C (respectively). The lower thermal limit (hourly decrease) for Ophiomastix annulosa was 12.8 0C. Lower salinity limit (hourly decrease) for Ophiomastix annulosa and Ophiocoma cf. dentata was 20.5 and 13 (respectively). The thermal window for Ophiomastix annulosa (hourly experiment) was between 12.8-37.0 0C. From the result, it can be assumed that these ophiuroids and asteroids species can acclimatize and survive to more rapid changing environment than slow changing environment; as long as the oxygen is available in sufficient amount.