Lohmann, Martina (2009) Environmental influences on the abundance and diversity of phytoplankton in the Spermonde Archipelago, Indonesia. (Diploma thesis), Christian-Albrechts-Universität zu Kiel, Kiel, Germany, 92 pp.

Text Dipl. 2009 Lohmann, M.pdf - Reprinted Version Restricted to Registered users only Available under License German copyright act UrhG. Download (8MB) | Contact

Abstract

The present study was part of the German-Indonesian project Science for the Protection of Indonesian Coastal Ecosystems (SPICE) and presents taxonomical characterisations of phytoplankton related to environmental factors in the Spermonde Archipelago, South Sulawesi (Indonesia). Studies were carried out at two islands near the coast off Makassar which differ in population, distance from the coast and conditions of the coral reefs. Sampling started in early April and lasted until late June 2008 in fortnightly intervals at New moon and Full moon using a small speed boat. Characterisation of environmental parameters included wind, waves, currents, temperature, oxygen, nutrients, seston and particulate organic matter. Sampling was conducted using a 5 L Niskin-bottle closed by hand at the surface and above deeper coral reefs close to the bottom by snorkelling at depths between 3 and 6 m depth. Temperature ranged from 28.2 to 30.5 °C and the pH from 8.1 to 8.3, all showing only minor variations within the sampling period. Weather was mostly dry and sunny, wind and waves were low with a direction from SE to NE and stayed fairly constant until May, changing then slightly to SE - S in June. Currents increased within the sampling period ranging from 2.8 to 4.5 cm s- 1 in early April and 12.2 - 13.3 cm s-1 in June. Phytoplankton abundance showed a significant decline from April to May, presumably caused by nitrogen limitation and to a lower degree probably by zooplankton grazing. At the same time a phase shift was observed changing from dominating diatoms to cyanobacteria. Nutrients showed consistent trends with declining concentrations of nitrate, phosphate and silicate that reached phytoplankton growth limiting values at lowest detected levels. A local upwelling event might have replenished nutrients in June, indicated by slightly increasing chlorophyll a, nitrate and phosphate concentrations along with slightly lower temperatures. Very high concentrations of silicate (2.1 - 9.8 μM) and ammonium (0.6 - 6.0 μM) indicate terrigenous runoff and riverine input. Steadily increasing ammonium concentrations, however, may also be an indication of increasing zooplankton grazing corresponding to phytoplankton decrease. No significant differences in phytoplankton abundance and diversity and environmental parameters were found between the two compared islands and between the sampling stations, indicating a strong mixing of the water column in this study area.

Actions (login required)

View Item