Search

Nutrient pollution of rivers is one of the prime threats facing the aquatic systems. In the present study, water samples (n = 20) were collected from the Karamana river (KR) during the pre-monsoon (PMN) and monsoon (MN) seasons of 2019 to analyze the seasonal variations. The water samples were analyzed for various physico-chemical parameters and to understand the nutrient status of the river. Furthermore, gross primary productivity (GPP), net primary productivity (NPP) and phytoplankton analysis were carried out to assess relationship among productivity variables and phytoplanktons. The study revealed that water quality is better during MN than PMN due to dilution. Among the two seasons, PMN showed relatively higher values for most of parameters like pH, EC, TDS, TA, Cl, NH4-N, NO3-N, NO2-N, Chl-a, GPP and NPP. The correlation among GPP, NPP, nutrients and other water quality parameters were done using SPSS. Phytoplankton of 23 genera belonging to three classes, namely Chlorophyceae (40%), Bacillariophyceae (40%) and Cyanophyceae (20%) have been identified in KR. The various phytoplankton diversity indices and statistical analyses were estimated and their relevance discussed in this paper. The nutrient enrichment in the downstream regions was affected the phytoplanktonic structure and diversity of the river. HIGHLIGHTS Water quality of Karamana river is better during monsoon.; Higher nutrient contents enhances productivity of Karamana river.; Higher values of nutrients and productivity variables noted at downstream stretches.; Phytoplankton analysis and diversity indices of Karamana river.; Palmer's index shows downstream stations are organically polluted.

Valuation of ecosystem services can play an important role in guiding decision-making concerning the restoration of natural ecosystems which is particularly important in tropical coastal wetlands due to their widespread deterioration. This study investigates the environmental status and provision of key ecosystem services of the Ashtamudi lake Ramsar site in Kerala, India, and explores the feasibility of wetland restoration scenarios through a multi-year program involving stakeholder workshops, primary market data collection, and stated preference non-market valuation. Relying on the input of local stakeholders, we apply a choice experiment to estimate the willingness to pay for wetland restoration scenarios with a focus on water quality, mangrove conservation and sustainable fisheries. Results indicate that local stakeholders attribute the greatest value to mangrove conservation, followed by water quality and sustainably managed fisheries. Furthermore, we show that the local residents’ willingness to pay for modest and moderate wetland improvement scenarios may outweigh the potential cost of the restoration projects, especially for modest restoration objectives and even under conservative assumptions regarding the benefits and costs of restoration. We discuss how such results can inform local policy in the development of sustainable management practices and act as a benchmark for the extensive network of wetlands in Kerala.

The sedimentation rates in Arctic fjords are influenced by the changes in the glacial inputs. The recent studies have indicated the retreat of glaciers due to climate change and subsequent increase in melt water outflow with high content of debris. The debris may contain natural and anthropogenically originated contaminants. The present study analysed the sedimentation rate in inner Kongsfjorden, Ny-Alesund, Svalbard using 210Pb/210Po dating technique. The sedimentation rate ranged between 0.22 and 0.37 cm/year during the last 112 years. The average sedimentation rate obtained was 0.28 cm/y. The rate has been increased during the last 20 years and it might be due to the increased influx of glacial melt water containing debris. Metals and other elements showed an increasing trend towards the surface and observed high deposition rate since 1970s, indicating influence of industrial emissions and it can be a potential threat to Arctic biota.

The arctic regions are facing serious environmental threats related to global warming. The marine geochemistry and metal sequestration in the marine sediments imply the present as well as past climatic conditions and elemental distribution, along with its dynamics. Various geochemical parameters were measured in the twelve sediment samples from Kongsfjorden. These were dominated by sand in the inner fjord and clay in the outer fjord area. The geochemical parameters such as organic carbon (OC) (mean 1.29%), inorganic carbon (CaCO3) (mean 10.16%), total nitrogen (TN) (mean 0.19%) and total phosphorus (TP) (mean 0.08%) show higher concentrations in the surface sediments of outer fjord regions. The concentrations of heavy metals are higher in the outer fjord regions and lower in the inner fjord regions. The various sediment quality-based indices analyses, such as the Enrichment Factor (EF) and geo-accumulation index, revealed high enrichment of heavy metals like Cu, Pb, Zn in the Kongsfjorden region, which is exposed to impending pollution from various sources. The modified PERI index values indicated that outer fjord region was under the level of considerable risk.