Seasonal variations in the water quality of six tropical micro- and mesotidal estuaries along the central west coast of India

2018 ◽  
Vol 69 (9) ◽  
pp. 1418 ◽  
Author(s):  
Lina L. Fernandes ◽  
Pratima M. Kessarkar ◽  
Suresh Suja ◽  
Durbar Ray ◽  
Mithila Bhat
Keyword(s):  
West Coast ◽  
Nutrient Dynamics ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Salinity Stratification ◽  
West Coast Of India ◽  
Estuarine Mixing ◽  
Run Off ◽  
Water Columns ◽  
Mixing Diagrams

Seasonal nutrient dynamics were investigated in four rivers with a microtidal range (Terekhol, Chapora, Sal and Talpona rivers) and were compared with those of two rivers with a mesotidal range (Zuari and Mandovi rivers) along the central west coast of India. Rainfall and freshwater discharge during the wet season led to salinity stratification of the water columns at the mouths of these rivers. Nutrient concentrations in all rivers were higher during the wet season than in the dry season due to considerable land run-off. Based on the estuarine mixing diagrams of the nutrients with regard to salinity, the mesotidal rivers showed greater flushing capacity and acted as corridors for the passage of nutrients between the estuary and open ocean. Conversely, of the microtidal rivers, the Terekhol and Chapora seemed to retain nutrients, whereas there was no indication of the presence of a nutrient sink or source in the Talpona River. The Sal River was eutrophic with high nutrient levels and acted as a source of phosphorus and nitrogen. Thus, the present study clearly illustrates the important role played by minor river estuaries in modifying nutrient concentrations during their transport from rivers to coastal waters and vice versa.

scholarly journals Estuarine turbidity maximum in six tropical minor rivers, central west coast of India

2017 ◽  
Vol 49 (4) ◽  
pp. 1234-1254 ◽  
Author(s):  
Lina L. Fernandes ◽  
V. Purnachandra Rao ◽  
Pratima M. Kessarkar ◽  
Suja Suresh
Keyword(s):  
West Coast ◽  
Dry Season ◽  
Turbidity Maximum ◽  
Estuarine Turbidity Maximum ◽  
Wet Season ◽  
Salinity Stratification ◽  
West Coast Of India ◽  
Driving Mechanisms ◽  
River Mouths ◽  
The Impact

AbstractUnderstanding patterns of erosion and sedimentation and their driving mechanisms is important for formulating a variety of estuarine management issues (conservation, shoreline protection, navigation, dredging and embanking). Therefore, the present study aims to determine the factors influencing the seasonal distribution and dynamics of suspended particulate matter (SPM) of two meso-(Mandovi and Zuari) and four micro-tidal (Terekhol, Chapora, Sal, and Talpona) river estuaries of Goa, on the central west coast of India. These estuaries exhibited salinity stratification near their mouths during the wet season and well-mixed water columns during the dry season. The SPM concentrations were two times higher in the wet season than in the dry season. Estuarine turbidity maximum (ETM) was a consistent feature in both the seasons at the mouth of the estuaries, except in the estuary of the Sal River. The in situ vertical distribution of SPM volume concentration and mean particle size allowed for a better visualization of the ETM formation and distribution. The gravitational circulation as well as flocculation at the salt–freshwater interface during the wet season and the impact of tidal and wind-induced currents at the river mouths during the dry season were primarily responsible for the formation of the ETMs.

Effect of tropical rainfall in structuring the macrobenthic community of Mandovi estuary, west coast of India

2013 ◽  
Vol 93 (7) ◽  
pp. 1727-1738 ◽  
Author(s):  
Udaykumar V. Gaonkar ◽  
Sanitha K. Sivadas ◽  
Baban S. Ingole
Keyword(s):  
West Coast ◽  
Temporal Dynamics ◽  
Environmental Parameters ◽  
Macrobenthic Community ◽  
Tropical Estuary ◽  
West Coast Of India ◽  
Run Off ◽  
Macrobenthic Assemblages ◽  
Macrofaunal Community ◽  
Mandovi Estuary

Macrofaunal community structure is determined by a number of environmental variables. The riverine run-off during the monsoon brings about drastic changes in the physico-chemical parameters of a tropical estuary. The aim of the present study was to investigate the influence of rainfall in structuring the benthic macrofaunal community of a tropical estuary. The temporal dynamics of the macrobenthic community in the monsoon dominated Mandovi estuary (central west coast of India) was studied fortnightly from June 2007 to June 2009. A fixed location, downstream of the Madovi river, was sampled for benthic and water parameters. Ten replicates were collected during each sampling date using a Van Veen grab (0.04 m2). The macrofaunal abundance showed temporal fluctuation. The multivariate analysis showed the clustering of the samples linked to the environmental parameters (CCA and LINKTREE). The temporal variation observed in the macrofaunal abundance was basically due to changes in abundance of the dominant species. The variation in macrofaunal abundance was brought about by the recruitment and settling of re-suspended adults. It can be concluded that the macrofaunal structuring is influenced by temporal changes in the environment associated with the annual monsoon rainfall. Hence climate induced changes in the monsoonal pattern may affect the macrobenthic assemblages of tropical estuaries.

Nutrient response to soil and litter metabolic activity in a transect across a seasonal wetland

2003 ◽  
Vol 54 (3) ◽  
pp. 243 ◽  
Author(s):  
S. Qiu ◽  
A. J. McComb ◽  
R. W. Bell ◽  
J. A. Davis
Keyword(s):  
Microbial Biomass ◽  
Microbial Activity ◽  
Nutrient Dynamics ◽  
Sand Dunes ◽  
Co2 Production ◽  
Nutrient Concentrations ◽  
Co2 Efflux ◽  
Wet Season ◽  
Surface Soils ◽  
Substrate Induced Respiration

Many wetlands in the interdunal depression of coastal sand dunes of the Swan Coastal Plain are surrounded by partially vegetated catchments. Although litter can be an important source of nutrients, little is known about litter related microbial activity in these catchments, especially its role in regulating nutrient concentrations in soils during the wet season. Heterotrophic microbial activity and phosphorus (P) dynamics were monitored before and after the onset of the wet season along transects from a vegetated catchment to the lakebed in Thomsons Lake, south-western Australia. Microbial activity was measured in the field as CO2 efflux (range from 47 to 176 mg CO2 m–2 h–1) and in the laboratory as substrate-induced-respiration (SIR; range from 11 to 133 μg g–1 h–1). Substrate-induced-respiration was positively correlated with soil organic content, and was concentrated in surface soils. In contrast, in the exposed lakebed most microbial biomass was below the surface, in the 10–30 cm depth zone. There were significant changes in nutrient dynamics in response to soil microbial activity. Before rain, P extracted by anion exchange membrane (PAEM) was well correlated with site litter and plant debris (r2 = 0.90, P�<�0.001), suggesting that PAEM in soils was litter-sourced. This relationship was modified during the wet season: there was an overall increase in microbial biomass P (PMB; from average 7.5 μg g–1 to 21.6 μg g–1), and a decrease in PAEM : PMB in surface soils. Along the study transect, the assimilation index PAEM : PMB declined towards the wetland, where soils were more silty and organic, and CO2 production was significantly higher. Our data suggest that heterotrophic microbial activity has a significant role in regulating P flux from catchment litter during the wet season, which would affect the mobility of litter-sourced P from catchment to the wetland.

Nitrogen levels in the Tully River - a long-term view

2001 ◽  
Vol 43 (9) ◽  
pp. 99-105 ◽  
Author(s):  
A. W. Mitchell ◽  
J. R. Reghenzani ◽  
M. J. Furnas
Keyword(s):  
River System ◽  
Low Flow ◽  
Nutrient Concentrations ◽  
Agricultural Activity ◽  
Wet Season ◽  
Potential Threat ◽  
Data Set ◽  
Particulate Nitrogen ◽  
Run Off ◽  
The Impact

Enhanced run-off of nutrients from agricultural development in catchments bordering the Great Barrier Reef (GBR) is regarded as a potential threat to inshore reefs. In an attempt to better understand the impact of river run-off, the Australian Institute of Marine Science (AIMS) initiated a sampling program to measure nutrient concentrations in rivers draining to the GBR shelf. Our longest data set is from the Tully River in the wet tropics, sampled in collaboration with the Bureau of Sugar Experiment Stations (BSES). After thirteen years, we ask whether there has been any change in river nutrient levels. Water samples were collected at monthly intervals, with additional, wet-season samples. In recent years, a trend of increase in nitrate (at low flow) and particulate nitrogen concentrations has been observed. In this period, a significant increase in agricultural activity has occurred within the Tully basin. The area under sugarcane and bananas has doubled and fertiliser nitrogen use has increased by 130%. Increased concentrations of nitrogen in the river system may be a consequence of this increase in agricultural activity.

Effects of fire regimes on herbaceous biomass and nutrient dynamics in the Brazilian savanna

2013 ◽  
Vol 22 (3) ◽  
pp. 368 ◽  
Author(s):  
Immaculada Oliveras ◽  
Sergio T. Meirelles ◽  
Valter L. Hirakuri ◽  
Cenira R. Freitas ◽  
Heloisa S. Miranda ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Nutrient Dynamics ◽  
Community Dynamics ◽  
Fire Regime ◽  
Dry Season ◽  
Brazilian Savanna ◽  
Nutrient Concentrations ◽  
Total Biomass ◽  
Long Term Effects ◽  
Wet Season

This study explores the long-term effects of fire treatments on biomass and nutrient pools in an open savanna from Central Brazil. Treatments included early, middle and late dry season burns every 2 years, a middle dry season burn every 4 years, and protection from fire on five 4-ha plots. We quantified aboveground biomass of graminoids and forbs/sub-shurbs, and their nutrient concentrations and stocks in both dry and wet seasons, and below-ground biomass down to 30-cm depth. We found strong differences between wet and dry season, with biomass and nutrient concentrations being highest in the wet season, across all fire treatments. Fire treatments had significant effects on plant nutrient stocks and root distribution, although total biomass was not affected. Concentrations of the most volatile nutrients (N, S, K and P) were higher in the herbaceous aboveground biomass of the quadrennial and the unburnt plots, suggesting that increases in fire frequency would reduce the amount of nutrients in aboveground biomass and increase the concentration of fine roots at the soil surface. Results highlight the role of fire in maintaining community dynamics in the Brazilian savanna. Overall, the quadrennial burn appears to be the optimal fire regime in open Cerrado vegetation.

scholarly journals Morphological and molecular evidence for first records and range extension of the Japanese seahorse, Hippocampus mohnikei (Bleeker 1853) in a bay-estuarine system of Goa, central west coast of India

PLoS ONE ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. e0220420
Author(s):  
Sushant V. Sanaye ◽  
Rakhee Khandeparker ◽  
Anantha Sreepada Rayadurga ◽  
Mamatha S. Shivaramu ◽  
Harshada Kankonkar ◽  
...  
Keyword(s):  
West Coast ◽  
Range Extension ◽  
Molecular Evidence ◽  
Estuarine System ◽  
West Coast Of India

Microplastics in seafood as an emerging threat to marine environment: A case study in Goa, West coast of India

Chemosphere ◽  
2020 ◽  
pp. 129359
Author(s):  
Mahua Saha ◽  
Akshata Naik ◽  
Aniket Desai ◽  
Mandar Nanajkar ◽  
Chayanika Rathore ◽  
...  
Keyword(s):  
Marine Environment ◽  
West Coast ◽  
West Coast Of India

Habitat ecology and substratum preference of brachyuran crabs of a tropical estuary, South-West coast of India

2021 ◽  
pp. 101709
Author(s):  
Prabhullachandran Lakshmi Devi ◽  
Aneykutty Joseph ◽  
Alphi Korath
Keyword(s):  
West Coast ◽  
Tropical Estuary ◽  
Habitat Ecology ◽  
West Coast Of India ◽  
South West ◽  
South West Coast ◽  
Brachyuran Crabs ◽  
Substratum Preference

Sedimentological responses to coastal dynamics along the Thane District, North Maharashtra, West Coast of India

2021 ◽  
Vol 7 (3) ◽  
Author(s):  
Sridhar D. Iyer ◽  
A. R. Gujar ◽  
V. Sanil Kumar ◽  
D. K. Naik ◽  
S. S. Gaonkar ◽  
...  
Keyword(s):  
West Coast ◽  
Coastal Dynamics ◽  
West Coast Of India
Sign in / Sign up

Export Citation Format

Share Document