Akter Sahina, K Abhilash Wodeyar, Nama Suman, Borah Simanku, Angmo Sonam, Deshmukhe Geetanjali, Nayak Binaya Bhusan, Ramteke Karankumar
ICAR-Central Institute of Fisheries Education, Mumbai, 400061, India.
ICAR-Central Inland Fisheries Research Institute, Regional Centre, Guwahati, Assam, 781006, India.
Environ Monit Assess. 2025 Jan 27;197(2):201. doi: 10.1007/s10661-024-13613-y.
Phytoplankton are diverse photosynthetic organisms in estuarine ecosystems and sensitive indicators of environmental changes. This study employed Generalized Additive Model (GAM) to explore the impact of environmental variables on the abundance of six dominant phytoplankton species in the tropical Karanja estuary, India. Data were collected from five sampling stations between January 2022 and March 2023. The GAM model explained ≥ 55% of the variability in species distribution, predicting that the Karanja estuary provides a suitable habitat for these phytoplankton. Spatiotemporal predictions revealed higher abundances of Asterionellopsis glacialis, Coscinodiscus sp., Pseudo-nitzschia pungens, Skeletonema costatum and Thalassionema frauenfeldii during post-monsoon and lower in pre-monsoon. Conversely, Odontella sinensis thrived during pre-monsoon. Optimal growth conditions included a water temperature range of 24-32 °C for O. sinensis, P. pungens and S. costatum, while chlorophyll-b concentrations between 1 and 20 mg/m favored A. glacialis, O. sinensis, P. pungens, S. costatum and T. frauenfeldii. P. pungens, S. costatum and T. frauenfeldii exhibited broad salinity tolerance ranging from 10-40‰. Additionally, Coscinodiscus sp., P. pungens and T. frauenfeldii were found in environments with nitrate content of 0.1-1 mg/L, while O. sinensis preferred silicate levels of 1-10 mg/L. Notably, these species serve as indicators of eutrophication, providing insights into ecosystem health. This study represents the first application of GAM for exploring phytoplankton-environment interactions in India, offering critical data for water quality management, pollution control and food web preservation. Policymakers can use these findings to develop evidence-based regulations that support proactive coastal management, enhance estuarine resilience to climate stressors and ensure sustainable resource conservation.
浮游植物是河口生态系统中多样的光合生物，也是环境变化的敏感指标。本研究采用广义相加模型（GAM）来探究环境变量对印度热带卡兰贾河口六种主要浮游植物物种丰度的影响。数据于2022年1月至2023年3月期间从五个采样站收集。GAM模型解释了物种分布中≥55%的变异性，预测卡兰贾河口为这些浮游植物提供了适宜的栖息地。时空预测显示，季风后期间，冰河星杆藻、圆筛藻属、尖刺伪菱形藻、中肋骨条藻和弗氏海线藻的丰度较高，而季风前较低。相反，中华齿状藻在季风前大量繁殖。最佳生长条件包括：中华齿状藻、尖刺伪菱形藻和中肋骨条藻的水温范围为24 - 32°C，而叶绿素b浓度在1至20 mg/m时有利于冰河星杆藻、中华齿状藻、尖刺伪菱形藻、中肋骨条藻和弗氏海线藻的生长。尖刺伪菱形藻、中肋骨条藻和弗氏海线藻表现出10 - 40‰的广泛盐度耐受性。此外，在硝酸盐含量为0.1 - 1 mg/L的环境中发现了圆筛藻属、尖刺伪菱形藻和弗氏海线藻，而中华齿状藻偏好1 - 10 mg/L的硅酸盐水平。值得注意的是，这些物种是富营养化的指标，为生态系统健康提供了见解。本研究是GAM在印度探索浮游植物 - 环境相互作用的首次应用，为水质管理、污染控制和食物网保护提供了关键数据。政策制定者可以利用这些发现制定基于证据的法规，以支持积极的海岸管理，增强河口对气候压力源的恢复力，并确保可持续的资源保护。
