Coastal Zones

Biography

Biography: Dr ShiHong Lee

Abstract

Microphytpbenthos (MPB) or benthic microalgal is unicellular microorganisms live in the surface and subsurface layers of the sediment in the coastal ecosystems. Despite of its microscopic size, it contributes to huge proportion of the worlds’ primary productivity. MPB is the major food source for filter feeders and benthic invertebrates, which in turns the primary food source for the larger animals. The biofilm mats formed by MPBs also alter the biostabilisation and sediment structure of the ecosystem. However, coastal area is a highly dynamic zone, and it is subjected to distinct changes, both physically and biogeochemically. Hence, MPB has to be well-adapted in order to survive in this hydrodynamic environment, particularly Tasmania, where the weather fluctuates dramatically seasonally. This study focuses on the photo-physiological performance of MPB towards different environmental stressors fortnightly throughout a year in two Tasmanian wetlands. The optimum photochemical efficiency (FV/FM) and maximum relative electron transport rate (rETRmax) show that MPB has better photosynthetic performance at both sampling sites during the winter than that of summer, when the temperature and irradiance are lower. This could mainly due to the combined effects of extremely high temperature and irradiance that have exceeded the maximum threshold MPB could withstand, which in turns stressing the MPB. The initial slope, Alpha (α) and light saturation parameter (EK) of of rETR vs Photosynthetically Active Radiation (PAR) curve are showing that MPB starts photosynthesising and reaches the maximum value quickly. This further supports the photosynthetic results that observed during the summer.