Search

During tidal cycles, semi-terrestrial fiddler crabs are subject to alternating periods of submersion and desiccation. Here, we compare physiological and biochemical adjustments to forced submersion and desiccation in two fiddler crabs from the Galapagos archipelago: the indigenous Leptuca helleri, and Minuca galapagensis. We examine ecological distributions and habitat characteristics using transect analysis; survival after 6 h forced submersion at different salinities (0, 21 and 42 ‰S), and after 6 or 12 h desiccation challenge, including alterations in hemolymph osmolality; and, oxidative stress responses in the gills and hepatopancreas, accompanying glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR) activities, and lipid peroxidase (LPO). We provide an integrated biomarker response (IBR) index for each species based on oxidative stress in each tissue and condition. Our transect study revealed that L. helleri occupies an intertidal niche while M. galapagensis is supralittoral, L. helleri being less resistant to submersion and desiccation. After 6 h submersion, L. helleri survived only at 21 ‰S while M. galapagensis survived at all salinities. Hemolymph osmolality decreased at 0 ‰S in M. galapagensis. After 6 h desiccation, osmolality decreased markedly in L. helleri but increased in M. galapagensis. Enzyme assays were not performed in L. helleri owing to high mortality on submersion/desiccation challenge. After submersion in M. galapagensis, hepatopancreas GPx activities decreased in 0 and 21 ‰S while GR activity was strongly inhibited at all salinities. Gill LPO decreased in 42 ‰S. On desiccation in L. helleri, GPx activity was inhibited in the hepatopancreas but increased in the gills. GST activity increased while LPO decreased in both tissues. After desiccation in M. galapagensis, hepatopancreas GPx activity increased. Both hepatopancreas and gill GST and GR activities and LPO were strongly inhibited. The IBR indexes for L. helleri were highest in fresh caught crabs, driven by gill and hepatopancreas LPO. For M. galapagensis, submersion at 21 ‰S contributed most to IBR, LPO in both tissues responding markedly. Leptuca helleri appears to be a habitat specialist adapted to a narrow set of niche dimensions while M. galapagensis survives over a much wider range, exhibiting little oxidative stress. The species’ physiological flexibilities and limitations provide insights into how fiddler crabs might respond to global environmental change on semi-arid islands.

Made available in DSpace on 2021-06-25T12:32:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 regional offices of the Ministerio del Ambiente de Ecuador (MAE) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) During tidal cycles, fiddler crabs undergo alternating periods of submersion and desiccation. We compare physiological and biochemical adjustments to submersion and desiccation challenge in two gelasminids from the Galapagos archipelago: the indigenous Leptuca helleri, and Minuca galapagensis. We examine population distributions and habitat characteristics; survival and hemolymph osmolality after 6 h submersion at several salinities, and after 6 or 12 h desiccation; and oxidative stress responses in the hepatopancreas and gills, accompanying glutathione enzyme antioxidant activities, and lipid peroxidation. We provide an integrated biomarker response index based on oxidative stress in each tissue, condition and species. Leptuca helleri occupies a restricted intertidal niche while M. galapagensis is supralittoral. Burrow density in M. galapagensis declined with increasing salinity and decreasing substrate moisture; L. helleri burrow density showed no correlation. After 6 h submersion, L. helleri survived only at 21 parts per thousand S while M. galapagensis survived from 0 to 42 parts per thousand S. After 6 h desiccation, hemolymph osmolality decreased markedly in L. helleri but increased in M. galapagensis. Antioxidant enzyme activities and lipid peroxidation in the hepatopancreas and gills showed tissue- and species-specific responses to submersion and desiccation challenge. The integrated biomarker response indexes for L. helleri were highest in control crabs, driven by oxidative stress. In M. galapagensis, submersion was the determining factor in both tissues. Minuca galapagensis is a generalist species while Leptuca helleri occupies a more restricted intertidal habitat. The species' respective physiological limitations and flexibilities provide insights into how fiddler crabs might respond to environmental change on semi-arid islands. Univ Reg Amazon Ikiam, Fac Ciencias Tierra & Agua, Km 7 Via Muyuna, Tena, Napo, Ecuador Univ Northern Iowa, Dept Biol, Cedar Falls, IA 50614 USA Univ Estadual Paulista, Campus Litoral Paulista, BR-11380972 Sao Vicente, SP, Brazil Univ Santa Cecilia, Dept Ecotoxicol, BR-11045907 Santos, SP, Brazil Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Biol, BR-14040901 Ribeirao Preto, SP, Brazil Univ Sao Paulo, Ctr Biol Marinha, BR-11600000 Sao Sebastiao, SP, Brazil Univ Estadual Paulista, Campus Litoral Paulista, BR-11380972 Sao Vicente, SP, Brazil regional offices of the Ministerio del Ambiente de Ecuador (MAE): MAE-DNB-CM-2017-0062-IKIAM CNPq: CNPq 303613/2017-3 FAPESP: 2017/04970-5

This investigation evaluated the bioaccumulation potential of the tropical estuarine bivalve Anomalocardia flexuosa for trace metals. To this aim, chemical and sedimentological analyses and bioaccumulation tests were performed. The sediments were mainly composed by fine-sands and mud, with variable levels of organic matter and CaCO

Protected areas (PAs) are critically important means to preserve species and maintain natural ecosystems. However, the potential impacts of chemical pollution on PAs are seldom mentioned in the scientific literature. Research on the extent of the occurrence of chemical pollution inside PAs and in-depth assessments of how chemical contaminants may adversely affect the maintenance of species abundance, species survival, and ecosystem functions are scarce to nonexistent. We investigated 1) the occurrence of chemical contaminants inside 119 PAs in Latin America from publically available databases, and 2) reviewed case studies of chemical contaminants and pollution in 4 Latin American PAs. Cases of chemical pollution and contamination inside Latin American PAs mostly originated from sources such as mining, oil, and gas extraction. To date, the focus of the research on chemical pollution research inside Latin American PAs has been primarily on the detection of contamination, typically limited to trace metals. Where management actions have occurred, they have been reactive rather than proactive. Protected areas established in wetlands are the most affected by chemical pollution. Based on the information from the pollution and/or contamination occurrence and the case studies analyzed, Latin American PAs are not well safeguarded from chemical pollution, resulting in both challenges and opportunities to conserve biodiversity and ecosystems. Integr Environ Assess Manag 2017;13:360-370. © 2016 SETAC.

Protected areas (PAs) are critically important means to preserve species and maintain natural ecosystems. However, the potential impacts of chemical pollution on PAs are seldom mentioned in the scientific literature. Research on the extent of the occurrence of chemical pollution inside PAs and in-depth assessments of how chemical contaminants may adversely affect the maintenance of species abundance, species survival, and ecosystem functions are scarce to nonexistent. We investigated 1) the occurrence of chemical contaminants inside 119 PAs in Latin America from publically available databases, and 2) reviewed case studies of chemical contaminants and pollution in 4 Latin American PAs. Cases of chemical pollution and contamination inside Latin American PAs mostly originated from sources such as mining, oil, and gas extraction. To date, the focus of the research on chemical pollution research inside Latin American PAs has been primarily on the detection of contamination, typically limited to trace metals. Where management actions have occurred, they have been reactive rather than proactive. Protected areas established in wetlands are the most affected by chemical pollution. Based on the information from the pollution and/or contamination occurrence and the case studies analyzed, Latin American PAs are not well safeguarded from chemical pollution, resulting in both challenges and opportunities to conserve biodiversity and ecosystems. Integr Environ Assess Manag 2017;13:360-370. © 2016 SETAC.