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<\/figure>\n<\/div>\n<\/div>\n<\/div>\n\n\n\nThis study focuses on how La Ni\u00f1a events impact the ocean\u2019s biophysical conditions in the Eastern Indian Ocean, a region stretching from southern Java to northwestern Australia. This area is particularly important because it is influenced by the Indonesian Throughflow (ITF) and strong upwelling systems, which supply nutrients to marine ecosystems and sustain rich biodiversity. Understanding how climate-driven events like La Ni\u00f1a affect these systems is essential for predicting shifts in marine productivity and managing fisheries sustainably.<\/p>\n\n\n\n
The researchers analyzed sea surface temperature (SST), dissolved oxygen (DO), nitrate levels, chlorophyll-a (Chlor-a), and nanoplankton concentrations from 2019 to 2022. Data were obtained using satellite observations (e.g., AquaMODIS, Copernicus Marine Service) and validated against in-situ measurements. This period coincided with a rare \u201ctriple-dip\u201d La Ni\u00f1a event, where the phenomenon persisted for three consecutive years.<\/p>\n\n\n\n
The results revealed that La Ni\u00f1a strongly alters ocean conditions:<\/p>\n\n\n\n
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- SST: During La Ni\u00f1a, significant variations in surface temperature were observed, with warming up to 31\u00b0C in some areas but cooling in regions affected by upwelling. These anomalies influence nutrient mixing and oxygen distribution.
<\/li>\n\n\n\n - Dissolved Oxygen: DO levels rose during certain seasons, reaching higher values in 2022 than in previous years. The ITF plays a crucial role in transporting oxygen-rich waters, but future declines in ITF strength could reduce oxygen availability.
<\/li>\n\n\n\n - Nitrate: Levels fluctuated with seasonal monsoon cycles. Upwelling events brought nutrients from deeper layers, but denitrification during oxygen-poor conditions reduced available nitrate at the surface. Peaks were observed during transitions from El Ni\u00f1o to La Ni\u00f1a.
<\/li>\n\n\n\n - Chlorophyll-a & Nanoplankton: Chlor-a, an indicator of phytoplankton biomass, varied with ENSO phases. Strong La Ni\u00f1a events led to decreases in Chlor-a, while weaker events or El Ni\u00f1o transitions boosted productivity. Nanoplankton trends closely mirrored Chlor-a patterns, highlighting their role in marine food webs.
<\/li>\n<\/ul>\n\n\n\nThe study emphasizes that climate variability directly impacts marine productivity by altering the availability of nutrients and oxygen, which in turn shapes phytoplankton growth and higher trophic levels, including fish stocks. These findings have important implications for fisheries management, food security, and climate adaptation strategies, as shifts in productivity influence livelihoods and ecosystems across the region.<\/p>\n\n\n\n
By combining advanced satellite data with field validation, the research provides a comprehensive picture of how La Ni\u00f1a reshapes ocean health in the Eastern Indian Ocean. It highlights the urgent need for adaptive resource management in the face of increasing climate variability and contributes to global understanding of ENSO\u2019s role in ocean systems.<\/p>\n\n\n\n