PALEOLIMNOLOGY STUDY OF LAKE SENTANI, JAYAPURA DISTRICT, PAPUA PROVINCE, WITH PALINOLOGY AS THE PROXY

• Main Author: Eka Padmaningrum, Novita
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/80390
• Institution: Institut Teknologi Bandung

Lake Sentani is considered one of Indonesia's priority lakes. However, changes in land use near the water source in the Cycloops Mountains have led to several issues, including the silting of the lake. Conducting paleolimnological studies of Lake Sentani is crucial to uncover past climatic phenomena and environmental changes, both caused by natural processes and human activities. The findings from this study can serve as valuable evaluation material for optimizing the management of the lake. The data used for this paleolimnological study consist of a 19 cm-long sedimentary lake core and literature studies. The methods employed include lithology analysis, which aims to determine the detailed lithology of each sediment layer, and palynological analysis in the form of pollen and spores. The palynological analysis is conductud to determine the relative age, depositional environment, paleoclimate, marine influence, and the impact of anthropogenic activities on vegetation around Lake Sentani. Based on Lake Hordorli radioactive dating data, the relative age of the Lake Sentani sediments obtained in the study area is 1,086 years ago, while based on palynological data, the sediments show a Pleistocene-Holocene Epoch, which can be equated to N22-N23 (Blow Zone) and NN19- NN21 (Martinian Zone). The overall depositional environment of the sediments was in the lake that experiences fluctuations. This can be seen from changes in the composition of fossil characteristics, from the dominance of back mangrove plants in zone 1, to the dominance of riparian and freshwater plants in zone 2, the dominance of riparian plants in zone 3, and changed back to domination of back mangroves plants in zone 4. During this period, there were fluctuations in climate change, but they were not significant and were not influenced by marine factors. Both anthropogenic activity and climate change have led in changes in vegetation composition. One notable change is the presence of Casuarina pollen, which is currently abundant. This indicates that the primary forest has been replaced by secondary forest due to disturbance in the past. Currently, the forest is reaching a more stable condition.