1
|
Vogl A, Desjardins K, Ponton DE, Winkler G, Amyot M. Diminishing Mercury Bioaccumulation in Zooplankton along an Estuarine Salinity Gradient. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2025; 59:4142-4152. [PMID: 39967451 DOI: 10.1021/acs.est.4c12263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2025]
Abstract
Estuarine transition zones (ETZs) are biogeochemically complex, nutrient-rich environments supporting diverse and productive food webs. They may also be sites of microbial production of methylmercury (MeHg) and bioaccumulation of this neurotoxicant at the base of the food web. However, the environmental drivers controlling these mechanisms are unclear. We studied the pattern of MeHg bioaccumulation in zooplankton along the 200 km ETZ of a large North American estuary, the St. Lawrence Estuary (Québec, Canada). Our approach integrated the dynamic variation in ETZ geochemistry, focusing on MeHg speciation change, alongside ecological factors, including community composition and stable isotopic tracers of diet and habitat. MeHg bioaccumulation decreased with distance downstream along the ETZ, driven by the salinity gradient and traced by the isotopic signature of sulfur in zooplankton. MeHg speciation modeling suggested that complexation to dissolved organic matter may be used as a proxy of the trophic transfer of MeHg to zooplankton. Further, the binding of MeHg to organic matter was reduced by the presence of chloride, thus reducing the trophic transfer of MeHg. We propose a conceptual model for MeHg cycling in ETZ of large estuaries that hypothesizes that higher-level consumers in turbid upstream regions may face heightened risks of MeHg toxicity but that Hg levels diminish drastically as salinity increases.
Collapse
Affiliation(s)
- Annabelle Vogl
- Déparment de Sciences Biologiques, Université de Montréal, Montréal, Québec H2V 0B3, Canada
| | - Kimberley Desjardins
- Déparment de Sciences Biologiques, Université de Montréal, Montréal, Québec H2V 0B3, Canada
- Ministère de l'Environnement, de la Lutte Contre les Changements Climatiques, de la Faune et des Parcs, Longueuil, Québec J4K 2TF, Canada
| | - Dominic E Ponton
- Déparment de Sciences Biologiques, Université de Montréal, Montréal, Québec H2V 0B3, Canada
| | - Gesche Winkler
- Institut des Sciences de la mer, Québec-Océan, Université du Québec à Rimouski, Rimouski, Québec G5L 2A6, Canada
| | - Marc Amyot
- Déparment de Sciences Biologiques, Université de Montréal, Montréal, Québec H2V 0B3, Canada
| |
Collapse
|
2
|
Zhao W, Gan R, Xian B, Wu T, Wu G, Huang S, Wang R, Liu Z, Zhang Q, Bai S, Fu M, Zhang Y. Overview of Methylation and Demethylation Mechanisms and Influencing Factors of Mercury in Water. TOXICS 2024; 12:715. [PMID: 39453135 PMCID: PMC11511217 DOI: 10.3390/toxics12100715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2024] [Revised: 09/15/2024] [Accepted: 09/25/2024] [Indexed: 10/26/2024]
Abstract
Mercury, particularly in its methylated form, poses a significant environmental and health risk in aquatic ecosystems. While the toxicity and bioaccumulation of mercury are well documented, there remains a critical gap in our understanding of the mechanisms governing mercury methylation and demethylation in aquatic environments. This review systematically examines the complex interplay of chemical, biological, and physical factors that influence mercury speciation and transformation in natural water systems. We provide a comprehensive analysis of methylation and demethylation processes, specifically focusing on the dominant role of methanogenic bacteria. Our study highlights the crucial function of hgcAB genes in facilitating mercury methylation by anaerobic microorganisms, an area that represents a frontier in current research. By synthesizing the existing knowledge and identifying key research priorities, this review offers novel insights into the intricate dynamics of mercury cycling in aquatic ecosystems. Our findings provide a theoretical framework to inform future studies and guide pollution management strategies for mercury and its compounds in aquatic environments.
Collapse
Affiliation(s)
- Wenyu Zhao
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China; (W.Z.); (B.X.); (T.W.); (Z.L.); (Q.Z.); (S.B.); (M.F.)
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
| | - Runjie Gan
- Guangxi Beitou Environmental Protection & Water Group Co., Ltd., Nanning 530025, China
| | - Bensen Xian
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China; (W.Z.); (B.X.); (T.W.); (Z.L.); (Q.Z.); (S.B.); (M.F.)
| | - Tong Wu
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China; (W.Z.); (B.X.); (T.W.); (Z.L.); (Q.Z.); (S.B.); (M.F.)
| | - Guoping Wu
- Ecological Environment Monitoring Station of Shunde, Foshan 528399, China; (G.W.); (S.H.)
| | - Shixin Huang
- Ecological Environment Monitoring Station of Shunde, Foshan 528399, China; (G.W.); (S.H.)
| | - Ronghua Wang
- Hengsheng Water Environment Treatment Co., Ltd., Guilin 541100, China
| | - Zixuan Liu
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China; (W.Z.); (B.X.); (T.W.); (Z.L.); (Q.Z.); (S.B.); (M.F.)
| | - Qin Zhang
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China; (W.Z.); (B.X.); (T.W.); (Z.L.); (Q.Z.); (S.B.); (M.F.)
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
| | - Shaoyuan Bai
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China; (W.Z.); (B.X.); (T.W.); (Z.L.); (Q.Z.); (S.B.); (M.F.)
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
| | - Mingming Fu
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China; (W.Z.); (B.X.); (T.W.); (Z.L.); (Q.Z.); (S.B.); (M.F.)
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
| | - Yanan Zhang
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China; (W.Z.); (B.X.); (T.W.); (Z.L.); (Q.Z.); (S.B.); (M.F.)
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
| |
Collapse
|
3
|
Jeong H, Ali W, Zinck P, Souissi S, Lee JS. Toxicity of methylmercury in aquatic organisms and interaction with environmental factors and coexisting pollutants: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 943:173574. [PMID: 38823721 DOI: 10.1016/j.scitotenv.2024.173574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/20/2024] [Accepted: 05/25/2024] [Indexed: 06/03/2024]
Abstract
Mercury is a hazardous heavy metal that is distributed worldwide in aquatic ecosystems. Methylmercury (MeHg) poses significant toxicity risks to aquatic organisms, primarily through bioaccumulation and biomagnification, due to its strong affinity for protein thiol groups, which results in negative effects even at low concentrations. MeHg exposure can cause various physiological changes, oxidative stress, neurotoxicity, metabolic disorders, genetic damage, and immunotoxicity. To assess the risks of MeHg contamination in actual aquatic ecosystems, it is important to understand how MeHg interacts with environmental factors such as temperature, pH, dissolved organic matter, salinity, and other pollutants such as microplastics and organic compounds. Complex environmental conditions can cause potential toxicity, such as synergistic, antagonistic, and unchanged effects, of MeHg in aquatic organisms. This review focuses on demonstrating the toxic effects of single MeHg exposure and the interactive relationships between MeHg and surrounding environmental factors or pollutants on aquatic organisms. Our review also recommends further research on biological and molecular responses in aquatic organisms to better understand the potential toxicity of combinational exposure.
Collapse
Affiliation(s)
- Haksoo Jeong
- Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Wajid Ali
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France; Univ. Lille, CNRS, Univ. Littoral Côte d'Opale, IRD, UMR-8187-LOG, Laboratoire d'Océanologie et de Géosciences, Station Marine de Wimereux, F-59000 Lille, France
| | - Philippe Zinck
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000 Lille, France
| | - Sami Souissi
- Univ. Lille, CNRS, Univ. Littoral Côte d'Opale, IRD, UMR-8187-LOG, Laboratoire d'Océanologie et de Géosciences, Station Marine de Wimereux, F-59000 Lille, France; Center of Excellence for Ocean Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan; Operation Center for Enterprise Academia Networking, National Taiwan Ocean University, Keelung 20224, Taiwan
| | - Jae-Seong Lee
- Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 16419, South Korea.
| |
Collapse
|
4
|
Neijnens FK, Moreira H, de Jonge MMJ, Linssen BBHP, Huijbregts MAJ, Geerling GW, Schipper AM. Effects of nutrient enrichment on freshwater macrophyte and invertebrate abundance: A meta-analysis. GLOBAL CHANGE BIOLOGY 2024; 30:e17094. [PMID: 38273479 DOI: 10.1111/gcb.17094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 10/27/2023] [Accepted: 11/24/2023] [Indexed: 01/27/2024]
Abstract
External nutrient loading can cause large changes in freshwater ecosystems. Many local field and laboratory experiments have investigated ecological responses to nutrient addition. However, these findings are difficult to generalize, as the responses observed may depend on the local context and the resulting nutrient concentrations in the receiving water bodies. In this research, we combined and analysed data from 131 experimental studies containing 3054 treatment-control abundance ratios to assess the responses of freshwater taxa along a gradient of elevated nutrient concentrations. We carried out a systematic literature search in order to identify studies that report the abundance of invertebrate, macrophyte, and fish taxa in relation to the addition of nitrogen, phosphorus, or both. Next, we established mixed-effect meta-regression models to relate the biotic responses to the concentration gradients of both nutrients. We quantified the responses based on various abundance-based metrics. We found no responses to the mere addition of nutrients, apart from an overall increase of total invertebrate abundance. However, when we considered the gradients of N and P enrichment, we found responses to both nutrients for all abundance metrics. Abundance tended to increase at low levels of N enrichment, yet decreased at the high end of the concentration gradient (1-10 mg/L, depending on the P concentration). Responses to increasing P concentrations were mostly positive. For fish, we found too few data to perform a meaningful analysis. The results of our research highlight the need to consider the level of nutrient enrichment rather than the mere addition of nutrients in order to better understand broad-scale responses of freshwater biota to eutrophication, as a key step to identify effective conservation strategies for freshwater ecosystems.
Collapse
Affiliation(s)
- Floris K Neijnens
- Department of Environmental Science, Radboud Institute for Biological and Environmental Sciences (RIBES), Radboud University, Nijmegen, The Netherlands
- Deltares, Delft, The Netherlands
| | - Hadassa Moreira
- Department of Environmental Science, Radboud Institute for Biological and Environmental Sciences (RIBES), Radboud University, Nijmegen, The Netherlands
| | - Melinda M J de Jonge
- Department of Environmental Science, Radboud Institute for Biological and Environmental Sciences (RIBES), Radboud University, Nijmegen, The Netherlands
| | - Bart B H P Linssen
- Department of Environmental Science, Radboud Institute for Biological and Environmental Sciences (RIBES), Radboud University, Nijmegen, The Netherlands
| | - Mark A J Huijbregts
- Department of Environmental Science, Radboud Institute for Biological and Environmental Sciences (RIBES), Radboud University, Nijmegen, The Netherlands
| | - Gertjan W Geerling
- Department of Environmental Science, Radboud Institute for Biological and Environmental Sciences (RIBES), Radboud University, Nijmegen, The Netherlands
- Deltares, Delft, The Netherlands
| | - Aafke M Schipper
- Department of Environmental Science, Radboud Institute for Biological and Environmental Sciences (RIBES), Radboud University, Nijmegen, The Netherlands
- PBL Netherlands Environmental Assessment Agency, The Hague, The Netherlands
| |
Collapse
|
5
|
Laske SM, Burke SM, Carey MP, Swanson HK, Zimmerman CE. Investigating effects of climate-induced changes in water temperature and diet on mercury concentrations in an Arctic freshwater forage fish. ENVIRONMENTAL RESEARCH 2023; 218:114851. [PMID: 36414108 DOI: 10.1016/j.envres.2022.114851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/28/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
The amount of mercury (Hg) in Arctic lake food webs is, and will continue to be, affected by rapid, ongoing climate change. At warmer temperatures, fish require more energy to sustain growth; changes in their metabolic rates and consuming prey with potentially higher Hg concentrations could result in increased Hg accumulation. To examine the potential implications of climate warming on forage fish Hg accumulation in Arctic lakes, we quantified growth and Hg accumulation in Ninespine Stickleback Pungitius pungitius under different temperature and diet scenarios using bioenergetics models. Four scenarios were considered that examined the role of climate, diet, climate × diet, and climate × diet × elevated prey Hg. As expected, annual fish growth increased with warmer temperatures, but growth rates and Hg accumulation were largely diet dependent. Compared to current growth rates of 0.3 g⋅y-1, fish growth increased at least 200% for fish consuming energy-dense benthic prey and decreased at least 40% for fish consuming pelagic prey. Compared to baseline levels, the Hg burden per kilocalorie of Ninespine Stickleback declined up to 43% with benthic consumption - indicating strong somatic growth dilution - but no more than 4% with pelagic consumption; elevated prey Hg concentrations led to moderate Hg declines in benthic-foraging fish and Hg increases in pelagic-foraging fish. Bioenergetics models demonstrated the complex interaction of water temperature, growth, prey proportions, and prey Hg concentrations that respond to climate change. Further work is needed to resolve mechanisms and rates linking climate change to Hg availability and uptake in Arctic freshwater systems.
Collapse
Affiliation(s)
- Sarah M Laske
- U. S. Geological Survey, Alaska Science Center, Anchorage, AK, USA.
| | - Samantha M Burke
- Department of Biology and Water Institute, University of Waterloo, Waterloo, Ontario, Canada
| | - Michael P Carey
- U. S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Heidi K Swanson
- Department of Biology and Water Institute, University of Waterloo, Waterloo, Ontario, Canada
| | | |
Collapse
|
6
|
He T, Mao X, Lin H, Hassan MM, Zhu S, Lu Q, Qin J, Su S. Methylmercury bioaccumulation in water flea Daphnia carinata by AIEgen. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 248:114271. [PMID: 36370670 DOI: 10.1016/j.ecoenv.2022.114271] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 10/10/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Mercury ion (Hg2+) is a toxic heavy metal ion and Hg2+ is convertible to methylmercury (MeHg) by many aquatic microorganisms, leading to bioaccumulation and biomagnification in aquatic organisms, which can interfere with brain development and function in humans. This study employs a newly developed AIEgen (Aggregation-induced emission fluorogen) to quantify and visualise the process of MeHg bioaccumulation in vivo on the species of water flea Daphnia carinata. Two approaches to MeHg absorption were taken, either by direct incubation in a MeHg solution or by indirect consumption of algae contaminated with MeHg. We analysed the relationship between the ratio of photoluminescence (PL) intensities (I585/I480) and MeHg concentration (CMeHg) and generated a master curve for determining MeHg concentration based on the measurement of PL intensities. Fluorescent image analysis showed the occurrence of MeHg in D. carinata to be mainly in the compound eyes, optic nerve and carapace. This study indicates that MeHg absorption can be quantified and visualised in the body of zooplankton, and the MeHg transfer to zooplankton is more likely through direct exposure than via indirect food intake. The accumulation of MeHg in the eye and the nervous system could be the cause of the high mortality of D. carinata exposed to MeHg in water.
Collapse
Affiliation(s)
- Tao He
- College of Fisheries, Southwest University, Chongqing 400715, China; Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangdong 510641, China
| | - Xiaodong Mao
- College of Fisheries, Southwest University, Chongqing 400715, China
| | - Hangyu Lin
- College of Fisheries, Southwest University, Chongqing 400715, China
| | - Md Mahbubul Hassan
- College of Science and Engineering, Flinders University, South Australia 5001, Australia
| | - Song Zhu
- College of Fisheries, Southwest University, Chongqing 400715, China
| | - Qun Lu
- College of Fisheries, Southwest University, Chongqing 400715, China
| | - Jianguang Qin
- College of Science and Engineering, Flinders University, South Australia 5001, Australia.
| | - Shengqi Su
- College of Fisheries, Southwest University, Chongqing 400715, China.
| |
Collapse
|
7
|
Nessel MP, Konnovitch T, Romero GQ, González AL. Nitrogen and phosphorus enrichment cause declines in invertebrate populations: a global meta-analysis. Biol Rev Camb Philos Soc 2021; 96:2617-2637. [PMID: 34173704 DOI: 10.1111/brv.12771] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 01/17/2023]
Abstract
Human-driven changes in nitrogen (N) and phosphorus (P) inputs are modifying biogeochemical cycles and the trophic state of many habitats worldwide. These alterations are predicted to continue to increase, with the potential for a wide range of impacts on invertebrates, key players in ecosystem-level processes. Here, we present a meta-analysis of 1679 cases from 207 studies reporting the effects of N, P, and combined N + P enrichment on the abundance, biomass, and richness of aquatic and terrestrial invertebrates. Nitrogen and phosphorus additions decreased invertebrate abundance in terrestrial and aquatic ecosystems, with stronger impacts under combined N + P additions. Likewise, N and N + P additions had stronger negative impacts on the abundance of tropical than temperate invertebrates. Overall, the effects of nutrient enrichment did not differ significantly among major invertebrate taxonomic groups, suggesting that changes in biogeochemical cycles are a pervasive threat to invertebrate populations across ecosystems. The effects of N and P additions differed significantly among invertebrate trophic groups but N + P addition had a consistent negative effect on invertebrates. Nutrient additions had weaker or inconclusive impacts on invertebrate biomass and richness, possibly due to the low number of case studies for these community responses. Our findings suggest that N and P enrichment affect invertebrate community structure mainly by decreasing invertebrate abundance, and these effects are dependent on the habitat and trophic identity of the invertebrates. These results highlight the important effects of human-driven nutrient enrichment on ecological systems and suggest a potential driver for the global invertebrate decline documented in recent years.
Collapse
Affiliation(s)
- Mark P Nessel
- Center for Computational and Integrative Biology, Rutgers University, 201 S. Broadway, Camden, NJ, 08103, U.S.A
| | - Theresa Konnovitch
- Center for Computational and Integrative Biology, Rutgers University, 201 S. Broadway, Camden, NJ, 08103, U.S.A.,Biology Department, La Salle University, 1900 W Olney Ave, Philadelphia, PA, 19141, U.S.A
| | - Gustavo Q Romero
- Department of Animal Biology, Institute of Biology, University of Campinas (UNICAMP), CP 6109, Campinas, São Paulo, 13083-862, Brazil
| | - Angélica L González
- Center for Computational and Integrative Biology, Rutgers University, 201 S. Broadway, Camden, NJ, 08103, U.S.A.,Biology Department, Rutgers University, Science Building, 315 Penn Street, Camden, NJ, 08102, U.S.A
| |
Collapse
|
8
|
Yu C, Xu Y, Yan Y, Xiao W, Liu M, Cheng M, He W, Xu F, Wang X. Mercury and methylmercury in China's lake sediments and first estimation of mercury burial fluxes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 770:145338. [PMID: 33517014 DOI: 10.1016/j.scitotenv.2021.145338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/17/2021] [Accepted: 01/17/2021] [Indexed: 06/12/2023]
Abstract
Lake sediments are key materials for mercury deposition and methylation. To understand the mercury concentrations in China's lakes, 100 lake surface sediment samples were collected from 35 lakes in 2014. Total mercury (THg), methylmercury (MeHg) concentrations and the annual Hg burial rates in lake sediments were measured. THg and MeHg concentrations in the sediment ranged from 13.6 to 1488 ng‧g-1 and 0.05 to 1.70 ng‧g-1, respectively, and urban lakes reported most high values, indicating direct anthropogenic inputs. The Inner Mongolia-Xinjiang Region (MX) and Qinghai-Tibet Plateau Region (QT) reported relatively lower mercury burial rates, while the Eastern Plain Region (EP), Northeast Mountain and Plain Region (NE), and Yunnan-Guizhou Plateau Region (YG) reported higher mercury burial rates. Regional variances of THg burial fluxes were dominated by atmospheric deposition, terrestrial input, and sediment accumulation rates in different lakes. In 2014, the estimated average THg burial rate in China's lakes was 139 μg‧m-2‧yr-1, comparable to the average in mid-latitude North America in recent years; however, due to China's much smaller lake area relative to NA, the annual THg burial flux in China was much lower than that in North America. EP and NE, where most freshwater aquatic products in China are harvested, accounted for 58.2% and 22.9%, respectively, of the THg burial flux. High sedimentary MeHg concentrations and MeHg:THg ratios were reported in most of the NE but low MeHg concentrations and MeHg:THg ratios were reported in EP. MeHg concentrations and MeHg:THg ratios were positively correlated with water COD levels and negatively correlated with average temperature. The results of this study indicate that in addition to the adjacent seas, lake sediments are an important mercury sink in China's aquatic environment, which could cause health risks due to MeHg intake, especially in NE.
Collapse
Affiliation(s)
- Chenghao Yu
- Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Yunping Xu
- College of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China
| | - Yunyun Yan
- Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Wenjie Xiao
- College of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China; Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Shenzhen 518055, China
| | - Maodian Liu
- Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China; School of the Environment, Yale University, New Haven, CT 06511, USA
| | - Menghan Cheng
- Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Wei He
- Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Fuliu Xu
- Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Xuejun Wang
- Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
| |
Collapse
|
9
|
Issa S, Simonsen A, Jaspers VLB, Einum S. Population dynamics and resting egg production in Daphnia: Interactive effects of mercury, population density and temperature. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:143625. [PMID: 33221017 DOI: 10.1016/j.scitotenv.2020.143625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/02/2020] [Accepted: 11/08/2020] [Indexed: 06/11/2023]
Abstract
Toxicity studies on freshwater organisms are commonly conducted by quantifying effects on asexual (clonal) reproductive rates in Daphnia, whereas studies of effects on sexual reproductive rates remain relatively rare. Sexual reproduction in Daphnia and the associated production of resting eggs allows them to survive unfavorable environmental conditions and is thus a crucial component of their long-term fitness. It also maintains genetic diversity within Daphnia populations and hence their potential for adaptation to new environmental conditions. This aspect of their biology may therefore be important to consider in toxicity studies. The aim of this study was to investigate for the first time how mercury (Hg) affects sexual versus asexual reproduction in Daphnia under varying environmental conditions. Specifically, we experimentally tested the interactive effects of Hg and temperature on the population dynamics of Daphnia magna. For this purpose, we exposed D. magna to environmentally relevant concentrations (0 μg/L, 0.5 μg/L and 2 μg/L) of Hg (in the form of mercury (II) chloride) found in stream water and measured biomass growth rate resulting from asexual reproduction, and resting egg production resulting from sexual reproduction. This was done at both 17 °C and 24 °C. Biomass growth rate did not vary across Hg treatments and depended mainly on temperature and population density. Density dependence of biomass growth rate was indeed more pronounced at 24 °C than at 17 °C, as resource limitation from intraspecific competition was further exacerbated by the rise in feeding rates with temperature. Density dependence of resting egg production was unaffected by Hg and temperature, but resting egg production was higher under Hg exposure at low temperature. These findings show that depending on environmental conditions, rates of sexual reproduction in D. magna may respond to metal exposure at lower concentrations than those impacting population growth during the asexual phase.
Collapse
Affiliation(s)
- Semona Issa
- Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway.
| | - Ane Simonsen
- Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway
| | - Veerle L B Jaspers
- Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway
| | - Sigurd Einum
- Centre for Biodiversity Dynamics (CBD), Department of Biology, Norwegian University of Science and Technology, Høgskoleringen 5, 7491 Trondheim, Norway
| |
Collapse
|
10
|
Eckley CS, Gilmour CC, Janssen S, Luxton TP, Randall PM, Whalin L, Austin C. The assessment and remediation of mercury contaminated sites: A review of current approaches. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 707:136031. [PMID: 31869604 PMCID: PMC6980986 DOI: 10.1016/j.scitotenv.2019.136031] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/07/2019] [Accepted: 12/07/2019] [Indexed: 04/13/2023]
Abstract
Remediation of mercury (Hg) contaminated sites has long relied on traditional approaches, such as removal and containment/capping. Here we review contemporary practices in the assessment and remediation of industrial-scale Hg contaminated sites and discuss recent advances. Significant improvements have been made in site assessment, including the use of XRF to rapidly identify the spatial extent of contamination, Hg stable isotope fractionation to identify sources and transformation processes, and solid-phase characterization (XAFS) to evaluate Hg forms. The understanding of Hg bioavailability for methylation has been improved by methods such as sequential chemical extractions and porewater measurements, including the use of diffuse gradient in thin-film (DGT) samplers. These approaches have shown varying success in identifying bioavailable Hg fractions and further study and field applications are needed. The downstream accumulation of methylmercury (MeHg) in biota is a concern at many contaminated sites. Identifying the variables limiting/controlling MeHg production-such as bioavailable inorganic Hg, organic carbon, and/or terminal electron acceptors (e.g. sulfate, iron) is critical. Mercury can be released from contaminated sites to the air and water, both of which are influenced by meteorological and hydrological conditions. Mercury mobilized from contaminated sites is predominantly bound to particles, highly correlated with total sediment solids (TSS), and elevated during stormflow. Remediation techniques to address Hg contamination can include the removal or containment of Hg contaminated materials, the application of amendments to reduce mobility and bioavailability, landscape/waterbody manipulations to reduce MeHg production, and food web manipulations through stocking or extirpation to reduce MeHg accumulated in desired species. These approaches often rely on knowledge of the Hg forms/speciation at the site, and utilize physical, chemical, thermal and biological methods to achieve remediation goals. Overall, the complexity of Hg cycling allows many different opportunities to reduce/mitigate impacts, which creates flexibility in determining suitable and logistically feasible remedies.
Collapse
Affiliation(s)
- Chris S Eckley
- U.S. Environmental Protection Agency, Region-10, 1200 6th Ave, Seattle, WA 98101, USA.
| | - Cynthia C Gilmour
- Smithsonian Environmental Research Center, 647 Contees Wharf Rd., Edgewater, MD 21037-0028, USA.
| | - Sarah Janssen
- USGS Upper Midwest Water Science Center, 8505 Research Way, Middleton, WI 53562, USA.
| | - Todd P Luxton
- US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Paul M Randall
- US Environmental Protection Agency, Office of Research and Development, Cincinnati, OH, USA.
| | - Lindsay Whalin
- San Francisco Bay Water Board, 1515 Clay St., Ste. 1400, Oakland, CA 94612, USA.
| | - Carrie Austin
- San Francisco Bay Water Board, 1515 Clay St., Ste. 1400, Oakland, CA 94612, USA.
| |
Collapse
|