Article
Environmental Sciences
Solomon Felix Dan, Enobong Charles Udoh, Jiaodi Zhou, Buddhi Wijesiri, Shuai Ding, Bin Yang, Dongliang Lu, Qianqian Wang
Summary: This study investigated the speciation of heavy metals in surface sediments of the Cross River Estuary in Nigeria. The results showed that some heavy metals had potential bioavailability and were influenced by factors such as sedimentary organic carbon, pH, and salinity. Cd was found to be the most polluted heavy metal.
MARINE POLLUTION BULLETIN
(2022)
Article
Environmental Sciences
Haifang Huang, Bin Yang, Zhiming Ning, Shengkang Liang, Zhenjun Kang, Dongliang Lu, Jiaodi Zhou, Hu Huang, Solomon Felix Dan
Summary: The study investigated the relationship between sedimentary nutrients and poorly-bound heavy metals in the Dafengjiang River Estuary and adjacent Sanniang bay. Results showed significant positive correlations between sedimentary nutrients, water column chlorophyll-a, and poorly-bound heavy metals. The study suggests that the remobilization of poorly-bound heavy metals in surface sediments enriched by labile organic matter can enhanced nutrient availability.
MARINE ENVIRONMENTAL RESEARCH
(2023)
Article
Environmental Sciences
Jingbo Chen, Ming Liu, Feiyu Wang, Yi Ding, Dejiang Fan, Houjie Wang
Summary: Reservoir construction has a significant impact on the natural transport of riverine water and sediment, as well as trace metals and pollutants. This study found that the migration and accumulation of trace metals were influenced by the adsorption of fine-grained sediments and oxidative processes. In the estuary, the trace metals were scavenged by reservoir-sourced fine particles and affected by the reducing environment.
SCIENCE OF THE TOTAL ENVIRONMENT
(2024)
Article
Environmental Sciences
Mary-Lou Tercier-Waeber, Fabio Confalonieri, Melina Abdou, Lionel Dutruch, Cecile Bossy, Marianna Fighera, Eric Bakker, Flavio Graziottin, Peter van der Wal, Jorg Schafer
Summary: The TracMetal probe allows high-resolution, simultaneous in-situ measurements of multiple potentially bioavailable trace metals, with autonomous operation and data transfer capabilities. Studies demonstrate the potential wide applicability of TracMetal in environmental monitoring.
Article
Chemistry, Multidisciplinary
Adrienne Patricia Hollister, Hannah Whitby, Michael Seidel, Pablo Lodeiro, Martha Gledhill, Andrea Koschinsky
Summary: This study focuses on the trace metal mixing and transport processes in the Amazon and Para River estuaries and mixing plume, finding that Cu primarily exists in soluble form and that organic ligands in dissolved samples kept free Cu levels below toxic levels for phytoplankton. The large overall river flow may minimize the impact of Cu pollution despite increasing anthropogenic activity over the past century.
Article
Chemistry, Multidisciplinary
Rintaro Moriyasu, James W. Moffett
Summary: This study investigated the complexation and exchangeability of copper in seawater using a solvent extraction method. The results revealed the existence of two distinct pools of labile and inert copper, and highlighted the widespread presence of inert copper. These findings have significant implications for the marine geochemistry and bioavailability of copper.
Review
Chemistry, Analytical
Katja Schmidt, Sophie A. L. Paul, Eric P. Achterberg
Summary: The geochemical behavior and bioavailability of trace metals are closely linked to their physical fractionation and chemical speciation. The DGT speciation technique allows for the challenging assessment of labile concentrations of various trace metals in ocean waters. This study demonstrates the applicability and sensitivity of DGT passive samplers for monitoring anthropogenic activities and studying natural processes in deep-sea environments.
TRAC-TRENDS IN ANALYTICAL CHEMISTRY
(2022)
Article
Ecology
Saba Ghattavi, Abolfazl Naji, Chee Kong Yap
Summary: The bioavailability of trace metals in coral skeletons and sediment samples from Larak and Qeshm Islands in the Persian Gulf was investigated. The results showed that Pb at the Qeshm Station and Cd and Zn at both Stations could have adverse biological effects due to high bioavailability. The studied coral reefs showed a high tendency for Pb adsorption, making them efficient bioindicators of Pb contamination.
REGIONAL STUDIES IN MARINE SCIENCE
(2023)
Article
Environmental Sciences
Laura Ferrans, Yahya Jani, Juris Burlakovs, Maris Klavins, William Hogland
Summary: This study investigates the speciation of metals in sediments from Malmfjarden bay, Sweden, and assesses the potential risk of metal pollution during dredging and using dredged sediments. The results show low pollution risk for Cr, Ni, and Fe during dredging activities, and medium risk for Pb and Zn. Overall, the investigated metals in Malmfjarden sediments are found to pose low risks of spreading during beneficial uses.
Review
Chemistry, Multidisciplinary
Siday Marrugo-Madrid, Marta Turull, Hao Zhang, Sergi Diez
Summary: Determining the concentration of an environmental pollutant may not accurately assess health risks if the pollutant is not bioavailable. Therefore, methods to determine pollutant bioavailability are more relevant for assessing toxicity. The diffusive gradient in thin films (DGT) technique has been used to measure labile compounds in the environment, with advancements in speciation and bioavailability of metals and metalloids.
ENVIRONMENTAL CHEMISTRY LETTERS
(2021)
Article
Oceanography
Dayana Mathew, Thundiyil Raju Gireeshkumar, Kareekunnan Shameem, Camey Monica Furtado, Kanneth Satheesan Arya, Pallikkoottathil Balakrishnan Udayakrishnan, Kizhakkepat Kalathil Balachandran
Summary: This study investigated the impact of water column hypoxia on the distribution and geochemical fractionation of trace metals in the seasonally hypoxic coastal environment in the southeastern Arabian Sea. The results showed that hypoxia led to a decrease in Fe and Mn content in sediments, a substantial decrease in the concentrations of metals such as Ni, Zn, and V under oxygen deficiency, and marked enrichment of Cr in sediments. The geochemical forms of trace metals also displayed considerable variability under hypoxia.
Article
Environmental Sciences
Camille Gaulier, Chunyang Zhou, Yue Gao, Wei Guo, Marek Reichstadter, Tianhui Ma, Willy Baeyens, Gabriel Billon
Summary: This study investigated the biogeochemical behavior of Cd, Co, Cr, Cu, Ni and Pb along the Scheldt estuary, highlighting the variations of trace metal speciation and distribution. The mobility and partitioning of trace metals were mainly driven by biogeochemical reactions influenced by estuarine physicochemical parameters. The study confirmed decreasing trend for particulate metals and rising concentrations for dissolved trace metals along the Scheldt.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Chemistry, Multidisciplinary
Sasa Marcinek, Ana Marija Cindric, Jasmin Padan, Dario Omanovic
Summary: This study investigated the distribution of several trace metals between five size fractions in the Krka River estuary. The results showed that the river was the dominant source for some metals, and dilution effect was observed for others. The truly dissolved fraction dominated certain metals, while others were mostly present in larger particles. The percentage of colloids varied with river flow, and this estuary had a limited input of terrigenous material compared to other coastal areas.
APPLIED SCIENCES-BASEL
(2022)
Article
Environmental Sciences
Karelys Umbria-Salinas, Astolfo Valero, Monica Wallner-Kersanach, Carlos Ferreira de Andrade, Maria Josefa Santos Yabe, Julio Cesar Wasserman, Katia Naomi Kuroshima, Hao Zhang
Summary: The study assessed seasonal variations in the concentrations of labile fractions of metals in shipyards located in estuarine areas on the Brazilian subtropical coast, indicating shipyards as hotspots of trace metals where Ecological Risk Assessment should be carried out.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Geochemistry & Geophysics
Jinshu Yan, Neha Sharma, Elaine D. Flynn, Daniel E. Giammar, Grace E. Schwartz, Scott C. Brooks, Pamela Weisenhorn, Kenneth M. Kemner, Edward J. O'Loughlin, Daniel Kaplan, Jeffrey G. Catalano
Summary: The study suggests that trace metal speciation in freshwater wetland soils and stream sediments is consistently dominated by a small set of recurring components, distinct for each metal, indicating a general geochemical phenomenon in anoxic soils and sediments with trace metals at background concentrations.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Environmental Sciences
Thajudeen Jabir, Puthiya Veettil Vipindas, Yousuf Jesmi, Sudheesh Valliyodan, Prabhakaran Meethal Parambath, Arvind Singh, Mohamed Hatha Abdulla
MARINE POLLUTION BULLETIN
(2020)
Letter
Oceanography
Sudheesh Valliyodan
Article
Environmental Sciences
V Sudheesh, G. V. M. Gupta, S. W. A. Naqvi
FRONTIERS IN MARINE SCIENCE
(2020)
Article
Environmental Sciences
G. V. M. Gupta, R. Jyothibabu, Ch Ramu, A. Yudhistir Reddy, K. K. Balachandran, V Sudheesh, Sanjeev Kumar, N. V. H. K. Chari, Kausar F. Bepari, Prachi H. Marathe, B. Bikram Reddy, Anil Kumar Vijayan
Summary: This study reveals for the first time that the world's largest hypoxic-anoxic zone along the west coast of India is formed through a natural process, with the extent and persistence of coastal oxygen deficiency depending on the degree of deoxygenation of source waters for the upwelling, confined to the central shelf region.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Anil Kumar Vijayan, B. Bikram Reddy, V Sudheesh, Prachi Hemant Marathe, Vishnu N. Nampoothiri, N. Harikrishnachari, P. Kavya, G. V. M. Gupta, M. Ramanamurthy
Summary: The study investigates the community composition of phytoplankton in the eastern Arabian Sea during the winter monsoon, highlighting distinct spatial heterogeneity in phytoplankton distribution between coastal and offshore regions. The dominance of diatoms in coastal waters and the presence of mixotrophic ecosystem in offshore waters were observed. Nutrient dynamics and hydrodynamics play a key role in structuring the phytoplankton assemblage in different regions of the eastern Arabian Sea during the winter monsoon period.
JOURNAL OF MARINE SYSTEMS
(2021)
Article
Environmental Sciences
Kusum Komal Karati, Chettiparambil Raghavan Ashadevi, Naroju Veera Harikrishnachari, Sudheesh Valliyodan, Munnooru Kumaraswami, Sura Appala Naidu, Mallavarapu Venkata Ramanamurthy
Summary: The study found that nutrient concentrations were higher in macro-tidal estuaries, leading to lower levels of dissolved oxygen and impacting the community structure of mesozooplankton. The copepod community in micro- and meso-tidal estuaries was dominated by meso- and euryhaline species, while in macro-tidal estuaries, euryhaline and coastal species were dominant, with an increase in jellyfish prevalence during the post-monsoon period.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2021)
Article
Environmental Sciences
P. V. Vipindas, T. Jabir, K. M. Mujeeb Rahiman, T. Rehitha, V Sudheesh, Y. Jesmi, A. A. Mohamed Hatha
Summary: This study aimed to explore the impact of anthropogenic organic matter on the microbial community distribution in the continental shelf sediments of the Southeastern Arabian Sea. It found significant variations in sediment C:N molar ratio and microbial community composition between the inner and outer shelf, with different types of bacteria dominating each region based on the source of organic matter.
MARINE POLLUTION BULLETIN
(2022)
Review
Oceanography
K. J. Albin, R. Jyothibabu, K. T. Alok, S. Santhikrishnan, S. Sarath, V Sudheesh, C. K. Sherin, K. K. Balachandran, C. R. Asha Devi, G. V. M. Gupta
Summary: This study investigates the response of phytoplankton size classes in the Eastern Arabian Sea to nutrient enrichment during monsoon seasons. The results show that phytoplankton biomass and primary production are relatively low during both monsoon seasons in the Northeastern Arabian Sea, but significantly higher in the Southeastern Arabian Sea during the Southwest Monsoon due to coastal upwelling. The differences in phytoplankton size fractions can be explained by the physical processes enabling nutrient entrainment into the euphotic layer and the characteristics of the surface mixed layer.
PROGRESS IN OCEANOGRAPHY
(2022)
Article
Environmental Sciences
S. S. Shaju, Ginchu Mariam Sunny, C. K. Sherin, N. N. S. Vishnu, Bikram Reddy, V Sudheesh, M. Prachi, Sanjeev Kumar, Anil Kumar Vijayan, G. V. M. Gupta
Summary: This study investigated the variability of POC in the eastern Arabian Sea and found that the distribution of POC is strongly influenced by seasonal physical and biological processes. The study also highlighted the importance of optical detection of POC in the EAS.
ENVIRONMENTAL MONITORING AND ASSESSMENT
(2022)
Article
Environmental Sciences
Mohammed I. Orif, Yasar N. Kavil, Radwan K. Al-Farawati, V. Sudheesh
Summary: Direct measurements in Al-Shabab and Al-Arbaeen lagoons along the Red Sea coast indicate these lagoons as significant sources of N2O to the atmosphere. The accumulation of N2O is caused by nitrifier-denitrification in oxygen-depleted bottom waters. The ongoing developmental activities may worsen hypoxia and associated biogeochemical feedbacks, emphasizing the need for continuous monitoring of the lagoons.
MARINE POLLUTION BULLETIN
(2023)
Article
Environmental Sciences
Bhavya Panthalil, Sanjeev Kumar, G. V. M. Gupta, Sudheesh Valliyodan, Jabir Thajudeen
Summary: The study used the 15N tracer technique to assess the seasonal variation in nitrate (NO3-) and ammonium (NH4+) uptake rates by total and nano + picoplankton in the Cochin estuary and adjacent coastal Arabian Sea. The results showed higher NO3- and NH4+ uptake rates in the Cochin estuary compared to the coastal Arabian Sea. The nearshore stations in the off Cochin area had high uptake rates, indicating the influence of eutrophication. The contribution of nano + picoplankton to the total DIN uptake rates in the Cochin estuary was 77-98%, highlighting their importance in the region's nitrogen cycling.
MARINE POLLUTION BULLETIN
(2023)
Review
Oceanography
C. K. Sherin, G. V. M. Gupta, V. Sudheesh, Ch. V. Ramu, Bikram Reddy, N. V. Harikrishnachari, Anil Kumar Vijayan
Summary: Repeat measurements of nutrients along the eastern Arabian Sea (EAS) in 2018-19 revealed nitrogen as the major limiting nutrient controlling primary production. The depth of nitracline (DNO3) was positively correlated with the upper boundary of thermocline (D26). Mixed layer nutrient availability varied with DNO3/D26, leading to low N/P ratios during nutrient enrichment events.
PROGRESS IN OCEANOGRAPHY
(2023)
Article
Environmental Sciences
Yet Yin Hee, Keith Weston, Suhaimi Suratman, Mohd Fadzil Akhir, Mohd Talib Latif, Sudheesh Valliyodan
Summary: A study was conducted in Brunei Bay, northwest Borneo, to understand the causes of low dissolved oxygen. The study found that hypoxia was widespread in the bottom waters during the monsoonal dry season, but less extensive during the wet season. The hypoxia in the dry season was primarily caused by riverine nutrient input and subsequent decomposition, while the wet season had less hypoxia due to reduced coastal primary production, intrusion of oxygen-rich water from the South China Sea, and increased advection of phytoplankton biomass out of the bay through horizontal flushing.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Environmental Sciences
Cindrella Joy Joseph, K. R. Renjith, Rose Santhosh, K. Ihjas, M. Digilarani, K. Naveena
Summary: This study examines the distribution of phosphorus in the surface sediments of the Beypore Estuary in southwest India. The results show that the total phosphorus content in the sediments is lower compared to other tropical estuaries, with organic-bound phosphorus being the dominant fraction. Unlike other estuaries, the study area has minor fractions of iron-bound and calcium-bound phosphorus. However, the bioavailable phosphorus remains consistent throughout the study period, indicating the presence of active phosphorus buffering in the estuary even without external input.
ENVIRONMENTAL MONITORING AND ASSESSMENT
(2023)
Article
Environmental Sciences
Yet Yin Hee, Keith Weston, Suhaimi Suratman, Mohd Fadzil Akhir, Mohd Talib Latif, Sudheesh Valliyodan
Summary: This study aims to understand the causes of low dissolved oxygen in Brunei Bay, northwest Borneo. It found that riverine nutrient input from the Padas river led to widespread hypoxia in bottom waters during the dry season. However, in the wet season, hypoxia was less extensive due to reduced coastal primary production, intrusion of oxygen-rich water from the South China Sea, and increased advection of phytoplankton biomass out of the bay.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
