ANALYSIS OF MARINE ECOLOGY DURING THE LAST WARMING PERIOD OF BØLLING-ALLERØD BASED ON THE ABUNDANCE AND DIVERSITY OF PLANKTONIC FORAMINIFERA IN THE MAKASSAR STRAIT

• Main Author: Rachmawati Purnomo, Maharani
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85186
• Institution: Institut Teknologi Bandung

Foraminifera is one of the proxies used to reconstruct global climate change, including the condition of marine ecosystems. This study focuses on the last BøllingAllerød warming period (13,102-14,920 years ago/yr). Reconstruction of aquatic ecology in this study uses analysis of the abundance and diversity of planktonic foraminifera. Furthermore, the relationship between marine ecology and sea surface temperature variability was also analyzed using Mg/Ca geochemical analysis of the Glebigerinoides ruber species, thermocline depth as seen from the comparison of thermocline dwellers with mixed layer dwellers, and Indonesian Throughflow (ITF) intensity in the Makassar Strait. From observations on 5 sediment samples, 10 genera and 17 species of planktonic foraminifera were obtained. The most dominant species in the study area are Globigerinita glutinata and Globigerinoides ruber, species that inhabit mixed layers and water paleoproductivity tends to be low. The Mg/Ca trend shows an average increase pattern of 0.2-0.6 mmol/mol or equivalent to an increase in Sea Surface Temperature (SST) of 0.5-1°C in SST. However, there was a brief period of cooling SST (13,453-14,001 kya) and the low Log (Zr/Rb) value caused by a rise precipitation and the Meltwater Pulse 1a (MWP 1a) event. In this period, the thermocline dwellers value was 39.76-47.31% (average 42.62%), indicating the thermocline layer's depth and the ITF strengthening. The change in depth of thermocline (DOT) that occurred at the TR1926-B research location are thought to be related to the shift in the ITCZ, the dominance of the western monsoon, and the a La Ni??a-like phenomenon around Indonesia.