Seasonal variability of modern benthic foraminifera assemblages in a mangrove ecosystem from northeast coastal Bay of Bengal

• Published in: Marine pollution bulletin 2023-03, Vol.188, p.114679-114679, Article 114679
• Main Authors: Mandal, Arkaprava, Ghosh, Anwesha, Saha, Ratul, Bhadury, Punyasloke
• Format: Article
• Language: English
• Subjects: Bays; Benthic foraminifera; Cyclonic Storms; Dissolved organic carbon; Ecosystem; Foraminifera; Humans; Mangrove; Porewater; Seasons; Standing crop
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2023.114679

Benthic foraminifera assemblages, nutrient dynamics of surface and porewater from 10 intertidal sites spanning over two years (2019–2020) covering two major estuaries in Sundarbans mangrove were evaluated to understand role of seasonal precipitation and primary production (driven by eddy nutrients) with a focus on standing crop. Benthic foraminifera abundance ranged between 280 individuals/10 cc in pre-monsoon (2019), 415 individuals/10 cc in post-monsoon 2019 and 630 individuals/10 cc in post-monsoon (2020). Standing crop was highest in post-monsoon coinciding with eddy nutrients driven stoichiometry and increase in abundance of large diatom cells. Calcareous and agglutinated foraminifer taxa Ammonia sp.1, Quinqueloculina seminulum, Entzia macrescens and Textularia sp. respectively were frequent. Entzia macrescens was found in dense mangrove vegetation sites; exhibited strong relationship with sediment texture and pore water total organic carbon. One of the major findings is mangroves with pneumatophores improves oxygen availability in sediment and leads to an increase in standing crop. [Display omitted] •Eddy driven nutrients increase benthic foraminifera standing crop in post-monsoon.•Oxygen availability influenced by pneumatophores in sediment leads to increase in foraminifera standing crop.•Entzia macrescens showed strong relationship with porewater carbon.