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aquatic ecosystems

Anton Gurkov, Anton Sadovoy, Ekaterina Shchapova, Cathleen Teh, Igor Meglinski, Maxim Timofeyev
In vivo physiological measurement is a major challenge in modern science and technology, as is environment conservation at the global scale. Proper toxicological testing of widely produced mixtures of chemicals is a necessary step in the development of new products, allowing us to minimize the human impact on aquatic ecosystems. However, currently available bioassay-based techniques utilizing small aquatic organisms such as fish embryos for toxicity testing do not allow assessing in time the changes in physiological parameters in the same individual...
2017: PloS One
Steven M Bartell, Shyam K Nair, Shanique Grant, Richard A Brain
Potential toxic effects of thiamethoxam (TMX) on non-target organisms and community structure of a generic Midwestern farm pond and emergent wetland were assessed using two versions of the Comprehensive Aquatic System Model, the CASMGFP - a generic farm pond model, and the CASMGWL - a generic wetland model. The CASMGFP and CASMGWL are integrated bioenergetics-based and habitat quality models that describe the daily biomass values of selected producer and consumer populations representative of generalized Midwestern farm ponds and emergent wetlands...
October 18, 2017: Environmental Toxicology and Chemistry
Qiang He, Yixi Qiu, Haohang Liu, Xingfu Sun, Li Kang, Li Cao, Hong Li, Hainan Ai
Phytoplankton density can be influenced by a wide range of factors whereas the role of suspended particulate matter (SPM) are not clear in river that annually subjected to hydrodynamics shift. Here, spatial-temporal variation of environmental parameters and phytoplankton density were studied from January 2013 to December 2014 in Yulin River, a tributary of the Three Gorges Reservoir, China. Laboratory experiments were conducted to elucidate the key parameter and interpret how it impacted phytoplankton density...
October 18, 2017: Scientific Reports
Raissa Marques Mendonca, Jennifer M Daley, Michelle L Hudson, Christian Schlekat, G Allen Burton, David Costello
In aquatic ecosystems, the cycling and toxicity of nickel (Ni) are coupled to other elemental cycles that can limit its bioavailability. Current sediment risk assessment approaches consider acid-volatile sulfide (AVS) as the major binding phase for Ni, but have not yet incorporated ligands that are present in oxic sediments. Our study aimed to assess how metal oxides play a role in Ni bioavailability in surficial sediments exposed to effluent from two mine sites. We coupled spatially explicit sediment geochemistry (i...
October 18, 2017: Environmental Science & Technology
Daniel J Becker, Matthew M Chumchal, Hugh G Broders, Jennifer M Korstian, Elizabeth L Clare, Thomas R Rainwater, Steven G Platt, Nancy B Simmons, M Brock Fenton
Mercury (Hg) is a persistent and widespread heavy metal with neurotoxic effects in wildlife. While bioaccumulation of Hg has historically been studied in aquatic food webs, terrestrial consumers can become contaminated with Hg when they feed on aquatic organisms (e.g., emergent aquatic insects, fish, and amphibians). However, the extent to which dietary connectivity to aquatic ecosystems can explain patterns of Hg bioaccumulation in terrestrial consumers has not been well studied. Bats (Order: Chiroptera) can serve as a model system for illuminating the trophic transfer of Hg given their high dietary diversity and foraging links to both aquatic and terrestrial food webs...
October 14, 2017: Environmental Pollution
Rajkumar Guchhait, Ankit Chatterjee, Shreyasi Gupta, Manashi Debnath, Dilip Mukherjee, Kousik Pramanick
Mercury is one of the key pollutants responsible for the degradation of natural aquatic ecosystems. Among the different forms of mercury that exist in the environment, mercuric chloride (HgCl2) is the dominant pollutant for freshwater environments as it is used as an ingredient in antiseptics, disinfectants and preservatives, insecticides, batteries and in metallurgical and photographic operations. Pollutant may exert their action on organisms or populations by affecting their normal endocrine function as well as reproduction...
October 13, 2017: General and Comparative Endocrinology
Laura M Salonen, Sara R Pinela, Soraia P S Fernandes, João Louçano, Enrique Carbó-Argibay, Marisa P Sarriá, Carlos Rodríguez-Abreu, João Peixoto, Begoña Espiña
Phycotoxins, compounds produced by some marine microalgal species, can reach high concentrations in the sea when a massive proliferation occurs, the so-called harmful algal bloom. These compounds are especially dangerous to human health when concentrated in the digestive glands of seafood. In order to generate an early warning system to alert for approaching toxic outbreaks, it is very important to improve monitoring methods of phycotoxins in aquatic ecosystems. Solid-phase adsorption toxin tracking devices reported thus far based on polymeric resins have not been able to provide an efficient harmful algal bloom prediction system due to their low adsorption capabilities...
October 6, 2017: Journal of Chromatography. A
S Amuno, A Jamwal, B Grahn, S Niyogi
Previous gold mining activities and arsenopyrite ore roasting activities at the Giant mine site (1948 to 2004) resulted in the release of high amounts of arsenic and trace metals into the terrestrial and aquatic ecosystems of Yellowknife, Northwest Territories, Canada. While elevated levels of arsenic has been consistently reported in surface soils and vegetation near the vicinity of the Giant mine area and in surrounding locations, systematic studies evaluating the overall health status of terrestrial small mammals endemic to the area are lacking...
October 13, 2017: Science of the Total Environment
Zhixin Song, Lixin Dong, Baoqing Shan, Wenzhong Tang
It is important to understand the potential bioavailability of heavy metals in the sediments of land-freshwater interfaces (between terrestrial and aquatic ecosystems). Therefore, we evaluated the pollution of Cr, Ni, Cu, Zn, As, and Cd in land-freshwater interface sediments/soils according to total concentrations, and used sequential extraction method to measure different fractions of Cd. Then, the diffusive gradients in thin films (DGT) technique was employed to study the potential bioavailability of metals...
October 9, 2017: Chemosphere
Swarnendu Banerjee, Abhishek Subramanian, Joydev Chattopadhyay, Ram Rup Sarkar
Toxic cyanobacteria blooms populate water bodies by consuming external nutrients and releasing cyanotoxins that are detrimental for other aquatic species, producing a significant impact on the plankton ecosystem and food web. To exercise population-level control of toxin production, understanding the biochemical mechanisms that explain cyanotoxin regulation within a bacterial cell is of utmost importance. In this study, we explore the mechanistic events to investigate the dependence of toxin microcystin on external nitrogen, a known regulator of the toxin, and for the first time, propose a kinetic model that analyzes the intracellular conditions required to ensure nitrogen dependence on microcystin...
October 16, 2017: Molecular BioSystems
Luis Orozco-Hernández, Adriana Andrea Gutiérrez-Gómez, Nely SanJuan-Reyes, Hariz Islas-Flores, Sandra García-Medina, Marcela Galar-Martínez, Octavio Dublán-García, Reyna Natividad, Leobardo Manuel Gómez-Oliván
17β-Estradiol, a natural hormone present at high concentrations in aquatic ecosystems, affects and modifies endocrine function in animals. In recent years research workers have expressed concern over its potential effects on aquatic organisms; however, little is known about its capacity to induce genetic damage or the pro-apoptotic effects of such damage on fish. Therefore, this study aimed to evaluate 17β-estradiol-induced cyto-genotoxicity in blood cells of the common carp Cyprinus carpio exposed to different concentrations (1 ng, 1 μg and 1 mg L(-1))...
October 6, 2017: Chemosphere
Serge Bakire, Xinya Yang, Guangcai Ma, Xiaoxuan Wei, Haiying Yu, Jianrong Chen, Hongjun Lin
Organic chemicals in the aquatic ecosystem may inhibit algae growth and subsequently lead to the decline of primary productivity. Growth inhibition tests are required for ecotoxicological assessments for regulatory purposes. In silico study is playing an important role in replacing or reducing animal tests and decreasing experimental expense due to its efficiency. In this work, a series of theoretical models was developed for predicting algal growth inhibition (log EC50) after 72 h exposure to diverse chemicals...
October 5, 2017: Chemosphere
Jie-Liang Liang, Xiao-Jing Li, Hao-Yue Shu, Pandeng Wang, Jia-Liang Kuang, Jun Liu, Miao-Miao Zhang, Wen-Sheng Shu, Li-Nan Huang
Microbial community composition is essential for aquatic ecosystem functions and has been explored across diverse environments and various spatial scales. However, documented patterns are often based on samples from spatially/geographically separated locations or sites. Here, we define sampling volume as spatial scale and examine (by Illumina 16S rRNA sequencing) microbial community composition over a scale of 1 mL to 10 L in an acid mine drainage. β-Diversity analysis revealed that all samples grouped very tightly according to spatial scales and variations between every two scales were significant...
October 1, 2017: FEMS Microbiology Ecology
Lorena M Durán-Riveroll, Allan D Cembella
Guanidinium toxins, such as saxitoxin (STX), tetrodotoxin (TTX) and their analogs, are naturally occurring alkaloids with divergent evolutionary origins and biogeographical distribution, but which share the common chemical feature of guanidinium moieties. These guanidinium groups confer high biological activity with high affinity and ion flux blockage capacity for voltage-gated sodium channels (NaV). Members of the STX group, known collectively as paralytic shellfish toxins (PSTs), are produced among three genera of marine dinoflagellates and about a dozen genera of primarily freshwater or brackish water cyanobacteria...
October 13, 2017: Marine Drugs
Camilla Krogh Frydkjær, Niels Iversen, Peter Roslev
The presence of microplastics in aquatic ecosystems is of increasing global concern. This study investigated ingestion, egestion and acute effects of polyethylene microplastics in Daphnia magna. Fate of regular shaped microplastic beads (10-106 µm) were compared with irregular shaped microplastic fragments (10-75 µm). Daphnia magna ingested regular and irregular microplastic with uptake between 0.7 and 50 plastic particles/animal/day when exposed to microplastic concentrations of 0.0001-10 g/L. Egestion of irregular fragments was slower than that of microplastic beads...
October 13, 2017: Bulletin of Environmental Contamination and Toxicology
Ruben Props, Marian L Schmidt, Jasmine Heyse, Henry A Vanderploeg, Nico Boon, Vincent J Denef
Species invasion is an important disturbance to ecosystems worldwide, yet knowledge about the impacts of invasive species on bacterial communities remains sparse. Using a novel approach, we simultaneously detected phenotypic and derived taxonomic change in a natural bacterioplankton community when subjected to feeding pressure by quagga mussels, a widespread aquatic invasive species. We detected a significant decrease in diversity within one hour of feeding, and a total diversity loss of 11.6 ± 4.1 % after 3h...
October 13, 2017: Environmental Microbiology
Ana Novoa, Ross Shackleton, Susan Canavan, Cathleen Cybèle, Sarah J Davies, Katharina Dehnen-Schmutz, Jana Fried, Mirijam Gaertner, Sjirk Geerts, Charles L Griffiths, Haylee Kaplan, Sabrina Kumschick, David C Le Maitre, G John Measey, Ana L Nunes, David M Richardson, Tamara B Robinson, Julia Touza, John R U Wilson
Alien species can have major ecological and socioeconomic impacts in their novel ranges and so effective management actions are needed. However, management can be contentious and create conflicts, especially when stakeholders who benefit from alien species are different from those who incur costs. Such conflicts of interests mean that management strategies can often not be implemented. There is, therefore, increasing interest in engaging stakeholders affected by alien species or by their management. Through a facilitated workshop and consultation process including academics and managers working on a variety of organisms and in different areas (urban and rural) and ecosystems (terrestrial and aquatic), we developed a framework for engaging stakeholders in the management of alien species...
October 9, 2017: Journal of Environmental Management
Daniel Stengel, Sarah Wahby, Thomas Braunbeck
In order to develop a test battery based on a variety of neurological systems in fish, three sensory systems (vision, olfaction, and lateral line) as well as nerve transmission (acetylcholine esterase) were analyzed in zebrafish (Danio rerio) embryos with respect to their suitability as a model for the screening of neurotoxic trace substances in aquatic ecosystems. As a selection of known or putative neurotoxic compounds, amidotrizoic acid, caffeine, cypermethrin, dichlorvos, 2,4-dinitrotoluene, 2,4-dichlorophenol, 4-nonylphenol, perfluorooctanoic acid, and perfluorooctane sulfonic acid were tested in the fish embryo test (OECD test guideline 236) to determine EC10 values, which were then used as maximum test concentration in subsequent neurotoxicity tests...
October 12, 2017: Environmental Science and Pollution Research International
Mahsa Mohammadi-Zadeh Khoshroo, Mehdi Shamsaie Mehrjan, Farzaneh Samiee, Mehdi Soltani, Seyed Pezhman Hosseini Shekarabi
Increasing of anthropogenic electromagnetic fields in aquatic environments has been recently become the core of attention. In this study, the effect of extremely low-frequency electromagnetic fields (50 Hz) on immune status and metabolic markers of common carp fingerling was assessed. The fish were exposed to extremely low-frequency electromagnetic fields at four intensities of 0.1, 0.5, 1, and 2 mT only once for 2 h; then, they were reared for 60 days. Results showed that the levels of aspartate aminotransferase (AST) and alanine transaminase (ALT) and alkaline phosphatase (ALP) were increased with an increase in the electromagnetic field intensity on 15 and 60 days post exposure...
October 11, 2017: Fish Physiology and Biochemistry
Dokyung Kim, Yooeun Chae, Youn-Joo An
In recent years, discarded plastic has become an increasingly prevalent pollutant in aquatic ecosystems. These plastic wastes decompose into microplastics, which not only pose a direct threat to aquatic organisms but also an indirect threat via adsorption of other aquatic pollutants. In this study, we investigated the toxicities of variable and fixed combinations of two types of microplastics [one coated with a carboxyl group (PS-COOH) and the other lacking this functional group (PS)] with the heavy metal nickel (Ni) on Daphnia magna and calculated mixture toxicity using a toxic unit model...
October 11, 2017: Environmental Science & Technology
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