Impact of seasonality on the nutrient concentrations in Gautami-Godavari Estuarine Mangrove Complex, Andhra Pradesh, India. Issue 1 (April 2018)

• Record Type: Journal Article
• Authors: Rao, Karuna; Priya, Namrata; Ramanathan, AL.
• Is Part Of: Marine pollution bulletin. Volume 129:Issue 1(2018)
• Page Start: 329
• Page End: 335
• Publication Date: 2018-04
• Subjects: Mangroves -- Dissolved nutrients -- Spatiotemporal variation -- Mixing model -- Nutrient ratio; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2018.02.052
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: Spatiotemporal variations of dissolved nutrients were studied along Gautami-Godavari mangrove ecosystem to delineate their sources and fate. Average values of nitrate (NO3 − ), dissolved silica (DSi) and phosphate (PO4 3− ) is 2.09 mg/l, 12.7 mg/l and 0.16 mg/l in wet season and 0.47 mg/l, 6.96 mg/l and 0.29 mg/l in dry season respectively. In wet season river discharge has significant influence on NO3 − and DSi. In dry season, NO3 − and PO4 3− are controlled by groundwater discharge, benthic exchange and various in situ processes owing to sediment redox condition. Mixing model shows net addition of phosphate in Coringa mangroves (95%) and Lower estuary (13%) and net removal of nitrate (24.79%) in Coringa mangrove and in estuary (58.9%). Thus present mangrove acts as net source for phosphate and net sink for nitrate and DSi. Nutrient ratio shows seasonal switching between potential Phosphorus and Nitrogen limitation in wet and dry season respectively. Highlights: River discharge is found to be the primary source of nitrate and dissolved silica in wet season. In dry season, many sources like organic matter remineralization, benthic flux, groundwater etc. supply nutrients. The contribution of groundwater should be considered which is generally neglected in estimating the nutrient budget. Seasonal switching is observed between potential Phosphorus and Nitrogen limitation in the wet and dry season respectively. The present mangrove acts as the net source for phosphate and net sink for nitrate and dissolved silica.