Variability of chlorophyll-a and diatoms in the frontal ecosystem of Indian Ocean sector of the Southern Ocean

• Published in: Polish Polar Research
• Main Authors: Rajani Kanta Mishra, Babula Jena, Anilkumar Narayana Pillai, Ravidas Krishna Naik, Venkateswaran Bhaskar Parli, Melena A Soares
• Format: Article in Journal/Newspaper
• Language: English
• Published: Polish Academy of Sciences 2017
• Subjects: Antarctic; Southern Ocean; chlorophyll-a; diatoms; Geology; QE1-996.5; Indian; Antarc*; Polar Research
• Online Access: https://doi.org/10.1515/popore-2017-0014; https://doaj.org/article/f10a6db7df6e462eb3e639c72bdce0f4

Phytoplankton composition plays a major role in biogeochemical cycles of the ocean. The intensity of carbon fixation and export is strongly dependent on the phytoplankton community. Yet, the contribution of different types of phytoplankton to the total production on various communities is still poorly understood in the Indian Ocean sector of Southern Ocean (SO). Therefore the variability of chlorophyll-a (Chl-a) and diatoms in the frontal ecosystems of the Indian sector of SO have been investigated along with the sea surface temperature (SST), sea surface wind (SSW), photosynthetically active radiation (PAR), and nutrients datasets for the period of 1998–2012. Combined analysis of in-situ, model and satellite observations indicate that the variability of Chl-a and diatoms were primarily influenced by light and wind. The Chl-a was higher at the sub-Antarctic front (SAF) followed by the sub-tropical front (STF) and the polar front (PF). The diatom concentration was higher at the SAF followed by the PF and STF. Maximum concentration of Chl-a and diatoms commonly observed at the SAF region are probably due to the moderate PAR, SST and wind. Dominance of diatoms at the PF may be attributed to their adaptability for low light conditions. The results from this study in the frontal ecosystems would help to understand the biogeochemical cycle of the Indian sector of the SO.