1
|
Schneider L, Fisher JA, Diéguez MC, Fostier AH, Guimaraes JRD, Leaner JJ, Mason R. A synthesis of mercury research in the Southern Hemisphere, part 1: Natural processes. Ambio 2023; 52:897-917. [PMID: 36943620 PMCID: PMC10073387 DOI: 10.1007/s13280-023-01832-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/30/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
Recent studies demonstrate a short 3-6-month atmospheric lifetime for mercury (Hg). This implies Hg emissions are predominantly deposited within the same hemisphere in which they are emitted, thus placing increasing importance on considering Hg sources, sinks and impacts from a hemispheric perspective. In the absence of comprehensive Hg data from the Southern Hemisphere (SH), estimates and inventories for the SH have been drawn from data collected in the NH, with the assumption that the NH data are broadly applicable. In this paper, we centre the uniqueness of the SH in the context of natural biogeochemical Hg cycling, with focus on the midlatitudes and tropics. Due to its uniqueness, Antarctica warrants an exclusive review of its contribution to the biogeochemical cycling of Hg and is therefore excluded from this review. We identify and describe five key natural differences between the hemispheres that affect the biogeochemical cycling of Hg: biome heterogeneity, vegetation type, ocean area, methylation hotspot zones and occurence of volcanic activities. We review the current state of knowledge of SH Hg cycling within the context of each difference, as well as the key gaps that impede our understanding of natural Hg cycling in the SH. The differences demonstrate the limitations in using NH data to infer Hg processes and emissions in the SH.
Collapse
Affiliation(s)
- Larissa Schneider
- School of Culture, History and Language. Australian National University, Coombs Bld 9 Fellows Rd, Acton. Canberra, ACT 2601 Australia
| | - Jenny A. Fisher
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522 Australia
| | - María C. Diéguez
- Instituto de Investigaciones en Biodiversidad y Medioambiente (Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional del Comahue), 1250 San Carlos de Bariloche (8400), Quintral Argentina
| | - Anne-Hélène Fostier
- Instituto de Química/Unicamp, Rua Josué de Castro, s/n – Cidade Universitária, Campinas, SP 13083-970 Brazil
| | - Jean R. D. Guimaraes
- Lab. de Traçadores, Inst. de Biofísica, Bloco G, CCS (Centro de Ciências da Saúde), Av. Carlos Chagas Filho 373, Rio de Janeiro, Ilha do Fundão CEP 21941-902 Brazil
| | - Joy J. Leaner
- Department of Environmental Affairs and Development Planning, Western Cape Government, 1 Dorp Street, Western Cape, Cape Town, 8001 South Africa
| | - Robert Mason
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340 USA
| |
Collapse
|
2
|
Lázaro WL, Díez S, Bravo AG, da Silva CJ, Ignácio ÁRA, Guimaraes JRD. Cyanobacteria as regulators of methylmercury production in periphyton. Sci Total Environ 2019; 668:723-729. [PMID: 30861408 DOI: 10.1016/j.scitotenv.2019.02.233] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/18/2019] [Accepted: 02/15/2019] [Indexed: 06/09/2023]
Abstract
Biotic mercury (Hg) methylation appears to depend on factors such as microbial activity and the concentration and bioavailability of Hg2+ to the Hg-methylating organisms. Recently, the presence of cyanobacteria has been linked with high methylmercury (MeHg) concentrations. The aim of this work was to test MeHg production in microcosms, in relation to the amount of periphytic cyanobacteria, dissolved organic matter (DOM) and phosphorus concentrations, as well as periphytic primary production rates. Water and periphyton samples were collected for cultivation and isolation of cyanobacteria from the Guaporé River floodplain, Brazil. We cultivated the periphyton in microcosms with different concentrations of cyanobacteria, total phosphorus and DOM. The highest net MeHg production (6.8 to 24.6% of added Hg d-1) occurred in the microcosm with added cyanobacteria, followed by microcosms with added phosphorus (6.1 to 11.4%) and added DOM (6.4 to 9.1%). Positive correlations were found between MeHg production, addition of cyanobacteria, phosphorus and DOM and periphytic primary productivity. Our results bring the first direct experimental evidence of the relevance of cyanobacteria and primary production as regulators of MeHg production in periphyton. These findings have numerous implications for the management of natural and engineered wetlands.
Collapse
Affiliation(s)
- Wilkinson L Lázaro
- Centro de Estudos em Limnologia Biodiversidade e Etnobiologia do Pantanal, Universidade do Estado de Mato Grosso (UNEMAT), Brasil. Avenida Santos Dummont, Cidade Universitária, 78200-000 Cáceres, MT, Brazil.
| | - Sergi Díez
- Environmental Chemistry Department, Institute of Environmental Assessment and Water Research (IDAEA-CSIC). C/Jordi Girona, 18-26, 08034 Barcelona, Spain.
| | - Andrea G Bravo
- Environmental Chemistry Department, Institute of Environmental Assessment and Water Research (IDAEA-CSIC). C/Jordi Girona, 18-26, 08034 Barcelona, Spain.
| | - Carolina J da Silva
- Centro de Estudos em Limnologia Biodiversidade e Etnobiologia do Pantanal, Universidade do Estado de Mato Grosso (UNEMAT), Brasil. Avenida Santos Dummont, Cidade Universitária, 78200-000 Cáceres, MT, Brazil; Rede Bionorte, Doutorado em Biodiversidade e Biotecnologia da Amazônia Legal. Avenida Fernando Correa da Costa, 2.367, Boa Esperança, 78060-900, Cuiabá, Brazil.
| | - Áurea R A Ignácio
- Centro de Estudos em Limnologia Biodiversidade e Etnobiologia do Pantanal, Universidade do Estado de Mato Grosso (UNEMAT), Brasil. Avenida Santos Dummont, Cidade Universitária, 78200-000 Cáceres, MT, Brazil.
| | - Jean R D Guimaraes
- Laboratório de Traçadores, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro (UFRJ). Av. Carlos Chagas Filho 373 Bloco G, CCS, Cidade Universitária, 21941-902, Rio de Janeiro, RJ, Brazil.
| |
Collapse
|
3
|
Coelho-Souza SA, Jenkins SR, Casarin A, Baeta-Neves MH, Salgado LT, Guimaraes JRD, Coutinho R. The Effect of Light on Bacterial Activity in a Seaweed Holobiont. Microb Ecol 2017; 74:868-876. [PMID: 28624904 DOI: 10.1007/s00248-017-0995-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 05/12/2017] [Indexed: 01/10/2024]
Abstract
Holobionts are characterized by the relationship between host and their associated organisms such as the biofilm associated with macroalgae. Considering that light is essential to macroalgae survival, the aim of this study was to verify the effect of light on the heterotrophic activity in biofilms of the brown macroalgae Sargassum furcatum during its growth cycle. Measurements of heterotrophic activity were done under natural light levels at different times during a daily cycle and under an artificial extinction of natural light during the afternoon. We also measured Sargassum primary production under these light levels in the afternoon. Both measurements were done with and without photosynthesis inhibitor and antibiotics. Biofilm composition was mainly represented by bacteria but diatoms, cyanobacteria, and other organisms were also common. When a peak of diatom genera was recorded, the heterotrophic activity of the biofilm was higher. Heterotrophic activity was usually highest during the afternoon and the presence of a photosynthesis inhibitor caused an average reduction of 17% but there was no relationship with Sargassum primary production. These results indicate that autotrophic production in the biofilm was reduced by the inhibitor with consequences on bacterial activity. Heterotrophic activity was mainly bacterial and the antibiotics chloramphenicol and penicillin were more effective than streptomycin. We suggest primary producers in the biofilm are more important to increase bacterial activity than the macroalgae itself because of coherence of the peaks of heterotrophic and autotrophic activity in biofilm during the afternoon and the effects of autotrophic inhibitors on heterotrophic activity.
Collapse
Affiliation(s)
- Sergio A Coelho-Souza
- Instituto de Estudos do Mar Almirante Paulo Moreira (IEAPM-RJ), Arraial do Cabo, Brazil.
- Universidade Federal do Rio de Janeiro (LTWCP/IBCCF/UFRJ), Rio de Janeiro, Brazil.
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Bloco Delta, Sala 222, Rua Acturus 03, Jardim Andares, São Bernardo do Campo, SP, CEP: 09606-070, Brazil.
- Centro de Biologia Marinha (CEBIMAR/USP), Rodovia Manoel Hypólito do Rego, km 131,5, São Sebastião, SP, CEP 11612-767, Brazil.
| | | | - Antonio Casarin
- Instituto de EStudos do Mar Almirante Paulo Moreira - IEAPM/RJ, Arraial do Cabo, Brazil
| | | | - Leonardo T Salgado
- Instituto de Pesquisas Jardim Botânico do Rio de Janeiro (IPJBRJ), Rio de Janeiro, Brazil
| | - Jean R D Guimaraes
- Universidade Federal do Rio de Janeiro (LTWCP/IBCCF/UFRJ), Rio de Janeiro, Brazil
| | - Ricardo Coutinho
- Instituto de Estudos do Mar Almirante Paulo Moreira (IEAPM-RJ), Arraial do Cabo, Brazil
| |
Collapse
|
4
|
Coelho-Souza SA, Miranda MR, Salgado LT, Coutinho R, Guimaraes JRD. Adaptation of the 3H-leucine incorporation technique to measure heterotrophic activity associated with biofilm on the blades of the seaweed Sargassum spp. Microb Ecol 2013; 65:424-36. [PMID: 22965803 DOI: 10.1007/s00248-012-0116-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 08/14/2012] [Indexed: 06/01/2023]
Abstract
The ecological interaction between microorganisms and seaweeds depends on the production of secondary compounds that can influence microbial diversity in the water column and the composition of reef environments. We adapted the (3)H-leucine incorporation technique to measure bacterial activity in biofilms associated with the blades of the macroalgae Sargassum spp. We evaluated (1) if the epiphytic bacteria on the blades were more active in detritus or in the biofilm, (2) substrate saturation and linearity of (3)H-leucine incorporation, (3) the influence of specific metabolic inhibitors during (3)H-leucine incorporation under the presence or absence of natural and artificial light, and (4) the efficiency of radiolabeled protein extraction. Scanning electron microscopy showed heterogeneous distribution of bacteria, diatoms, and polymeric extracellular secretions. Active bacteria were present in both biofilm and detritus on the blades. The highest (3)H-leucine incorporation was obtained when incubating blades not colonized by macroepibionts. Incubations done under field conditions reported higher (3)H-leucine incorporation than in the laboratory. Light quality and sampling manipulation seemed to be the main factors behind this difference. The use of specific metabolic inhibitors confirmed that bacteria are the main group incorporating (3)H-leucine but their association with primary production suggested a symbiotic relationship between bacteria, diatoms, and the seaweed.
Collapse
Affiliation(s)
- Sergio A Coelho-Souza
- Biotecnologia Marinha, Instituto de Ciências do Mar Almirante Paulo Moreira (IEAPM), Arraial do Cabo-RJ, Brazil.
| | | | | | | | | |
Collapse
|