Bioaccumulation and biomagnification of mercury and methylmercury in four sympatric coastal sharks in a protected subtropical lagoon

ABSTRACT High levels of eutrophication in coastal lagoons due to human activity have been documented worldwide. Among the main impacts observed are anoxia, hypoxia, toxic algal blooms, fish kills, loss of biodiversity and loss of bathing. This study aimed to evaluate the evolution of the trophic state of Lagoa da Conceição, a subtropical lagoon located in an urbanized watershed on the island of Santa Catarina - Brazil. Spatio temporal patterns of stratification and eutrophication were investigated to understand the main biochemical changes over time. The water quality data were obtained from field campaigns supplemented with literature of the last 15 years. The vertical structure of the water column and the trophic state were evaluated by the stratification index and the TRIX index, respectively. Analyses of variance were performed in order to identify possible temporal variations in vertical stratification and trophic level. Eutrophication effects on biogeochemical cycles were verified through a multi-dimensional cluster analysis (MDS) and correlations between variables related to physical, chemical and biological processes were verified by principal component analysis (PCA). The results showed that the water column is homogeneous in all regions except in the central region of the lagoon, and the highest ammonia concentrations and lowest dissolved oxygen concentrations with periods of anoxia are observed in bottom waters. The study looked at the high trophic level of the lagoon and its inability to process the biogeochemical changes imposed by urban development.

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Long-term spatial dynamics in vegetated seascapes: fragmentation and habitat loss in a human-impacted subtropical lagoon

Marine Ecology ◽

10.1111/maec.12259 ◽

2015 ◽

Vol 37 (1) ◽

pp. 200-214 ◽

Cited By ~ 9

Author(s):

Rolando O. Santos ◽

Diego Lirman ◽

Simon J. Pittman

Keyword(s):

Habitat Loss ◽

Spatial Dynamics ◽

Subtropical Lagoon

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A comparative analysis of the organic and inorganic carbon content of Halimeda and Penicillus (Chlorophyta, Bryopsidales) in a coastal subtropical lagoon

Botanica Marina ◽

10.1515/bot-2018-0095 ◽

2019 ◽

Vol 62 (4) ◽

pp. 323-326

Author(s):

Danielle Catherine Hatt ◽

Ligia Collado-Vides

Keyword(s):

Coastal Waters ◽

Inorganic Carbon ◽

Carbonate Sediment ◽

Term Study ◽

Sediment Production ◽

Long Term Study ◽

Organic And Inorganic Carbon ◽

Maximum Contribution ◽

Subtropical Lagoon

Abstract Standing stocks of the calcifying algae, Halimeda and Penicillus, have remained stable over the 10 years surveyed (2007–2017) in Florida Bay (USA), a subtropical lagoon. The maximum contribution of calcium carbonate (CaCO3; 779.75 g m−2) was lower compared to tropical lagoons. Halimeda was more abundant and had higher inorganic:organic carbon ratios compared to Penicillus. The abundance of Penicillus varied across the surveyed sites, Sprigger Bank, Bob Allen Keys, and Duck Key, while its inorganic:organic carbon ratios did not vary significantly. Our long-term study provides a critical baseline that can help understand fluctuations in carbonate sediment production by calcareous algae in subtropical coastal waters.

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Environmental forcing on the flux of organic-walled dinoflagellate cysts in recent sediments from a subtropical lagoon in the Gulf of California

The Science of The Total Environment ◽

10.1016/j.scitotenv.2017.11.269 ◽

2018 ◽

Vol 621 ◽

pp. 548-557 ◽

Cited By ~ 5

Author(s):

Tomasa Cuellar-Martinez ◽

Rosalba Alonso-Rodríguez ◽

Ana Carolina Ruiz-Fernández ◽

Anne de Vernal ◽

Lourdes Morquecho ◽

...

Keyword(s):

Gulf Of California ◽

Dinoflagellate Cysts ◽

Environmental Forcing ◽

Recent Sediments ◽

Subtropical Lagoon

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Effect of a rainfall pulse on phytoplankton bloom succession in a hyper-eutrophic subtropical lagoon

Marine and Freshwater Research ◽

10.1071/mf13314 ◽

2015 ◽

Vol 66 (1) ◽

pp. 60 ◽

Cited By ~ 3

Author(s):

Pei-Jie Meng ◽

Hung-Jen Lee ◽

Kwee Siong Tew ◽

Chung-Chi Chen

Keyword(s):

Nutrient Dynamics ◽

Phytoplankton Bloom ◽

Heavy Precipitation ◽

Inorganic Nutrients ◽

Phytoplankton Species ◽

Nutrient Pulse ◽

Chaetoceros Curvisetus ◽

Before And After ◽

Physical And Chemical ◽

Subtropical Lagoon

In the present study, we sought to understand the succession of phytoplankton species, after a natural nutrient pulse, in a subtropical lagoon located in southern Taiwan. The lagoon was surrounded by aquaculture ponds. The present study was performed during the wet summer season, before and after an episode of heavy precipitation. Before rainfall commenced, both the phosphate concentration and the level of phytoplankton were relatively low. After heavy precipitation, physical and chemical measurements indicated that significant amounts of dissolved inorganic nutrients had drained into the lagoon. A phytoplankton bloom occurred; organism levels reached 77.6×105 cells L–1. The dominant organism was Chaetoceros curvisetus (99.3%). After the bloom ceased, the levels of inorganic nutrients, especially silicate, fell. Phytoplankton became of low abundance once more. At the end of our study period, the ecosystem was dominated once more by diatoms (75.8%); this may have been caused by a low-level nutrient pulse following rainfall that occurred one day before final sampling. Overall, our results suggest that the bloom succession of phytoplankton species was principally dependent on nutrient dynamics in the lagoon, which was associated with nutrients discharged from drainage after heavy rainfall.

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