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Safeguarding temperature loggers on remote coral reefs – lessons learned from relocating loggers in the Chagos archipelago

  • Thursday, 31 December 2009 23:00
Harris, A., Gibbs, R., Schleyer, J., Taylor, K., Sheppard, C. - REEF ENCOUNTER Newsletter of the International Society for Reef Studies

Introduction

Research into sea surface temperature and impacts of thermal stresses on coral reefs has led to the increasing use of compact sea temperature loggers on reefs. While deployment itself is easy, ensuring they survive in situ for 2–3 years until recovery is less so. We had received numerous accounts of disappearance of anything from 50–100% of groups of deployed loggers, sometimes as soon as a few weeks later, even with those placed in sheltered lagoons.

Underwater temperature loggers have improved enormously in recent years, with diverse products commercially available. Durable, pressure resistant, compact devices, capable of recording over 30,000 temperature samples with accuracies of up to 0.1oC and with a bat tery life commonly exceeding five years, are widely available for prices below US$150 each. When these are deployed at sites to which return visits are infrequent and widely spaced, we need to ensure a good recovery rate. We developed a technique to reliably secure 20 StowAway TB132 Tidbit data loggers. We wanted to place these on reefs at a range of depths to 25 m deep on several atolls in the Chagos Archipelago, at sites that would not be revisited for 2–3 years.