Seasonal Changes in River Plankton and Their Environment

Greg Howard
2nd March, 2024

Seasonal Changes in River Plankton and Their Environment

Image Source: Natural Science News, 2024

Key Findings

  • In the Shipra River, Himalayas, 48 types of plankton were found, changing with seasons
  • Winter favored plant-like plankton, while summer and monsoon saw more animal-like types
  • Seasonal shifts in water conditions like temperature and oxygen levels impacted plankton
Understanding the health of a river system is a complex task that involves studying various biological indicators and environmental factors. One such recent study[1] conducted by researchers at Delhi University has shed light on the intricate relationship between plankton populations and environmental variables in the Shipra River, a tributary of the Kosi River in the Central Himalayas. Plankton, the tiny organisms that drift in water bodies, are critical components of aquatic ecosystems. They serve as the base of the food web, and changes in their communities can indicate shifts in water quality and ecosystem health. In this study, researchers collected data from four locations along the Shipra River, two upstream (S1 and S2) and two downstream (S3 and S4), to understand the distribution and abundance of different plankton species. The study identified 48 genera of plankton, which included both phytoplankton (plant-like organisms) and zooplankton (animal-like organisms), across ten different classes. It was observed that the winter season saw a dominance of phytoplankton such as Navicula spp., Nitzchia spp., and Diatom spp., while the summer and monsoon seasons were characterized by a higher presence of zooplankton, including species like Daphnia spp., Cyclops spp., Keratella spp., and Brachionus spp. To assess the diversity and evenness of these plankton communities, researchers used various diversity indices. These indices, including the Shannon-Weiner's index (H), Simpson's diversity index (1-D), and Evenness Index (E), help determine how evenly the plankton are distributed across the different species and how diverse the community is as a whole. In addition to biological measurements, the study also focused on a range of environmental variables such as water temperature, specific conductivity (which measures the water's ability to conduct electricity and is related to the amount of dissolved salts or ions in the water), total dissolved solids, dissolved oxygen, nitrate, and ammonium ions. The results showed that these factors varied significantly with the seasons, affecting the plankton communities. The researchers applied statistical methods like Canonical Correspondence Analysis, K-dominance plots, cluster analysis, and NMDS (Non-metric Multidimensional Scaling) analysis to illustrate the dynamic nature of the plankton communities. These methods allowed them to visualize and understand the relationships between the plankton species and the physicochemical conditions of the river. This study's findings are important because they provide insights into the seasonal dynamics of aquatic ecosystems in the Himalayan region, which have been less explored compared to other areas. Moreover, the research underscores the importance of smaller streams and tributaries in maintaining the health and biodiversity of larger river systems. The findings of the Delhi University study echo those of previous research[2] on the Kabar Tal (KT) wetland in Bihar, which also highlighted the significant impact of seasonal variations on water quality and ion concentrations. In that study, it was found that certain ions like chloride and nitrate were higher in the summer, while others such as sodium, potassium, calcium, and magnesium peaked in the winter. These seasonal patterns in ion concentrations can influence the suitability of water for agricultural purposes, just as seasonal changes affect plankton communities in the Shipra River. In conclusion, the Delhi University study contributes to the broader understanding of how seasonal changes influence aquatic ecosystems. By examining the dynamic relationship between plankton populations and environmental variables, this research offers valuable data that can be used for the conservation and management of river systems. The study also complements previous findings[2], showing that seasonal patterns are a common thread affecting various aspects of water quality and ecosystem health. These insights are crucial for developing strategies to protect and restore these vital freshwater resources.

EnvironmentEcologyMarine Biology


Main Study

1) Temporal Variations in Plankton Communities and Environmental Factors in the Shipra, a Central Himalayan Tributary of the Kosi River in Uttarakhand, India.

Published 29th February, 2024

Related Studies

2) Spatial and seasonal variability in the water chemistry of Kabar Tal wetland (Ramsar site), Bihar, India: multivariate statistical techniques and GIS approach.

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