Tsunamis and Marine Life

Abstract

The 26 December 2004 tsunami in the Indian Ocean exerted far reaching temporal and spatial impacts on marine biota. Our synthesis was based on satellite data acquired by the Laboratory for Tropical Marine Environmental Dynamics (LED) of the South China Sea Institute of Oceanology, China, near-shore as well as deep-sea observations by the National Institute of Oceanography (NIO), India, National Institute of Ocean Technology, India (NIOT), Central Institute of Brackish Water Aquaculture (CIBA, 2005), India, augmented by observations made by agencies in Sri Lanka and Indonesia. The tsunami impacted both the oceanic waters and the near-shore waters. The massive dislocation of sub-surface deep waters was similar to an upwelling, and was characterized by a decrease in sea surface temperature (SST) by about 1 degree C, increase in suspended particles, and increased nutrients which probably caused an increase in phytoplankton biomass to the northeast of Sumatra, and offChcnnai. The time-series data for chlorophyll a compiled for 2000-2005 showed an increase in phytoplankton biomass (is greater than 0.35 chl-a mu g l sup(-1)) between mid-January and February 2005 soon after the tsunami. Two weeks after the tsunami, in January 2005 a phytoplankton bloom developed with chlorophyll a (greater than 0.5 mu g l sup(-1)) in a 300 x 300 km area to the southeast of Sri Lanka and north of Aceh Province of Indonesia in the Andaman Sea. Similarly, in the near-shore waters near Chennai, a bloom dominated by the diatom Lauderia annulata developed and could be attributed to nutrient enrichment. The submarine land slides, and geomorphic changes resulted in extensive losses in coastal population, structures, mariculture operations, and coral reefs. A schematic analysis of the impacts of the tsunami on various habitats and biotopes is presented.