Seasonal dynamics of phytoplankton community and functional groups in a tropical river

Abstract

post-monsoon at four sampling stations in Karatoya River, Bangladesh. A total of 54 phytoplankton species were recorded under four classes, viz. Chlorophyceae (21 species) Cyanophyceae (16 species), Bacillariophyceae (15 species), and Euglenophyceae (2 species). A significantly higher total cell density of phytoplankton was detected during the pre-monsoon season (24.20 × 10 3 cells/l), while the lowest in monsoon (9.43 × 10 3 cells/l). The Shannon-Wiener diversity index varied significantly (F = 16.109, P = 000), with the highest value recorded during the post-monsoon season. Analysis of similarity (ANOSIM) identified significant variations among the three seasons (P < 0.0001, R = 0.9518). The similarity percentage (SIMPER) analysis pinpointed Ulothrix spp. (Melosira granulate and Cymbella spp.) as the most contributory species are causing such a noticeable difference. Fifty-four phytoplankton species recorded during the study period were classified into 20 functional groups, whereas D/J/M/MP/X1 was considered the most abundant FG in the Karatoya River. FGs of the Karatoya River were influenced mainly by the nutrients (PO 4 -P and NO 3 -N) enrichments. As a novel investigation on FGs of phytoplankton in Bangladesh, this study recommends additional surveys in other rivers and floodplains to improve our understanding of phytoplankton diversity and functional groups.

Seasonal influence of physicochemical and climatic parameters on phytoplankton diversity and abundance pattern in community managed semi- impacted floodplain wetland

“…The transparency was found minimum during monsoon this might be due to the high rainfall, sediments, silts, and debris inorganic and organic particles were washing into the waterbody. Therefore transparency reduces during monsoons (Haque et al, 2021). The DO was maximum during post-monsoon which was similar to the study of Sharif et al, (2017).…”

“…The density and diversity of phytoplankton in freshwater are in uenced by several water variables of the aquatic ecosystem (Ahmed and Wanganeo, 2015). Thus, any changes in physic-chemical properties, especially in water body nutrients, can modify phytoplankton's diversity and density (Atique and An, 2020; Haque et al, 2021;Haque, 2006). Therefore, monitoring the existence and nonexistence of phytoplankton in an aquatic ecosystem mustgive essential information and common connections within a water body (Thakur et al, 2013).…”

Out of the blue: the independent activity of sulfur-oxidizers and diatoms mediate the sudden color shift of a tropical river

“…S2). Cymbellaceae (found both by amplicon sequencing and microscopy) have been reported in other tropical rivers [64][65][66] including rivers from Costa Rica [67]. Other diatom taxa commonly reported in these rivers, such as Nitzschia or Gomphonema [64,65,67,68] were however not detected in our study.…”

Key Drivers Influencing the Presence and Absence of Micropterus salmoides and Their Effect on Native Fish Communities and Biotic Integrity

“…However, there are several confounding factors to be held responsible for the overall decline of ecological integrity. The potential confounding factors that have severely affected the riverine biotic integrity and functionality, other than the IAFS, could be regarded as changing climate, surmounting chemical and nutrient enrichment, altered flow regime, habitat degradation, and in-stream installments [8,9,[81][82][83][84]. The IAFS can exploit the empty niches, eventually declining the functional richness and causing the ultimate loss of functional diversity.…”