Impact of Hydroelectric Projects on Bivalve Clams in the Sharavathi Estuary of Indian West Coast

Boominathan, M.; Ravikumar, G.; Chandran, M. D. Subash; Ramachandra, T. V.

doi:10.2174/1874213001407010052

Cited by 5 publications

(2 citation statements)

References 8 publications

(6 reference statements)

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“…However, during 2015, instead of the expected irruption of S. cylindraceus, M. morphina dominated (Figure 2, Table 1). The salinity tolerance range of S. cylindraceus is 15-65 23 , whereas M. morphina was recorded in salinities of 7.5-58.2 during the current study (see also [24][25][26][27] ). Both species are euryhaline, but M. morphina may have established itself ahead of S. cylindraceus during low salinity conditions prevailing during the few years leading up to 2015.…”

Section: Resultsmentioning

confidence: 76%

Population irruption of the clam Meretrix morphina in Lake St Lucia, South Africa

Miranda¹,

Peer²,

Perissinotto³

et al. 2017

S. Afr. J. Sci.

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The thick-shelled clam Meretrix morphina, previously referred to as Meretrix meretrix, now occurs in the west Indian Ocean region, along the eastern seaboard of Africa, from the Red Sea to the Mlalazi Estuary, close to the Tugela River. Its presence in South Africa is only of recent recording. Meretrix morphina was detected for the first time in Lake St Lucia in 2000. The population declined and was not detected from 2005 until 2011, most likely as a result of a severe drought that resulted in widespread desiccation and hypersalinity in the lake. The system then experienced increased freshwater input resulting in lower salinities from 2011 until 2014, during which time M. morphina reappeared and their population gradually increased. In 2015, M. morphina became abundant in St Lucia, attaining unprecedented densities of 447 ind./m2. Biomass, expressed as a fresh weight, varied in the different basins of St Lucia, ranging from 195 g/m2 at Lister’s Point to 1909.8 g/m2 at Catalina Bay. However, in 2016, when drought conditions returned, M. morphina disappeared. This species appears to thrive under brackish salinities and high temperatures. It is able to establish large populations with high biomass and can become dominant. However, M. morphina is sensitive to desiccation and hypersaline conditions. This clam has substantial commercial value and is exploited along the African east coast, particularly in Mozambique. In future, it may feature more prominently in South African estuaries. However, the ecology of M. morphina is still largely unknown.

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Section: Resultsmentioning

confidence: 76%

Population irruption of the clam Meretrix morphina in Lake St Lucia, South Africa

Miranda¹,

Peer²,

Perissinotto³

et al. 2017

S. Afr. J. Sci.

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“…A decrease in forests generally tends to increase wetlands in small/medium undammed catchments such as the Aghanashini. However, it is essential to note that earlier studies on the wetlands of the Aghanashini river report more than 120 species of birds contribute to the productivity of mudflats through nutrient cycling in the form of potash and nitrogen source (Bhat et al, 2014;Boominathan et al, 2014Boominathan et al, , 2008. A decrease in forested areas and conversion of forests to agricultural land in the Aghanashini catchment as shown in our present study, could possibly be inferred as a potential threat to these mudflats.…”

Section: Land Use and Land Cover Changesmentioning

confidence: 99%

Effects of land use and climate change on water scarcity in rivers of the Western Ghats of India

Sharannya

Venkatesh

Mudbhatkal

et al. 2021

Environ Monit Assess

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CC on regional hydrology, a scenario approach was adopted and three scenarios depicting near-future (2006-2040), mid-future (2041-2070), and farfuture (2071-2100) based on climate were established. The present rate of LU change indicated a reduction in forest cover by 20% and an increase in urbanized areas by 9.5% between 1988 and 2016. It was estimated that forest cover in the catchments may be expected to halve compared to the presentday LU (55% in 2016 to 23% in 2075), along with large-scale conversion to agricultural lands (13.5% in 2016 to 49.5% in 2075). As a result of changes to LU and forecasted climate, it was found that rivers in the Western Ghats of India might face scarcity of fresh water in the next two decades until the year 2040. However, because of large-scale LU conversion toward the year 2050, streamflow in rivers might increase as high as 70.94% at certain times of the year. Although an increase in streamflow is perceived favorable, the streamflow changes during summer and winter may be expected to affect the cropping calendar and crop yield. The changes to streamflow were also linked to a 4.2% increase in ecologically sensitive wetlands of the Aghanashini river catchment.

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Assessment of pollution and risks associated with microplastics in the riverine sediments of the Western Ghats: a heritage site in southern India

Amrutha

Shajikumar

Warrier

et al. 2022

Environ Sci Pollut Res

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There is very little knowledge on microplastic pollution in the Western Ghats (WG), a heritage site in southwest India. To address this, we have studied the spatiotemporal variations of sedimentary microplastics (MPs) from the River Sharavathi, a pristine river in the Western Ghats (WG), southern India. The rich biodiversity in the region makes it relevant to analyse the distribution of this emerging pollutant that is causing harm to the biota and the ecosystem. We analysed the sedimentological and carbon content (organic and inorganic) of these sediments and explored their relationship with MPs. Finally, risk assessment indices such as the Pollution Load Index (PLI), the Polymer Hazard Index (PHI), and the Potential Ecological Risk Index (PERI) were calculated to detect the levels of plastic pollution. The concentration of MPs ranged from 2.5 to 57.5 pieces/kg and 0 to 15 pieces/kg during the pre-monsoon and post-monsoon seasons, respectively. The dip in the MPs’ abundance during the post-monsoon season was due to the extremely high rainfall in the river basin during July–August 2019, which would have entrained the sedimentary MPs and transported them to the coast/Arabian Sea. Smaller MPs (0.3–1 mm) were more abundant than the larger MPs (1–5 mm), mainly due to the breakdown of sedimentary plastics by physical processes. Fragments, films, foams, and fibres were the main categories of MPs, and the main polymers were polyethylene, polyethylene terephthalate, and polypropylene. No significant relationship was observed between the sedimentological properties and microplastics, which may be due to the different physical properties of sediments and microplastics. The PLI, PHI, and PERI indices suggest different contamination levels in the river basin. Based on the PLI scores, all the samples belong to the hazardous level I suggesting minor risk category, and the risk of microplastic pollution falls under the high to hazardous risk category based on the PHI values. The PERI value ranged from 160 to 440 and 40 to 2240 during the pre-monsoon and post-monsoon seasons, respectively. The risk assessment in a region known for its rich biodiversity is crucial, as the data can be used by the district administration to mitigate plastic pollution.

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Impact of Hydroelectric Projects on Bivalve Clams in the Sharavathi Estuary of Indian West Coast

Cited by 5 publications

References 8 publications

Population irruption of the clam Meretrix morphina in Lake St Lucia, South Africa

Population irruption of the clam Meretrix morphina in Lake St Lucia, South Africa

Effects of land use and climate change on water scarcity in rivers of the Western Ghats of India

Assessment of pollution and risks associated with microplastics in the riverine sediments of the Western Ghats: a heritage site in southern India

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