The Relationship between Mollusks and Oxygen Concentrations in Todos Santos Bay, Baja California, Mexico

Kuk-Dzul, José Gabriel; Díaz‐Castañeda, Victoria

doi:10.1155/2016/5757198

Cited by 9 publications

(6 citation statements)

References 46 publications

(55 reference statements)

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“…Some gastropod taxa and functional groups also provide evidence of historical increases of hypoxic conditions. For example, Anachis , a genus that is sensitive to hypoxic conditions (Díaz Asencio et al 2016, Kuk‐Dzul and Díaz‐Castañeda 2016), declined in relative abundance in the deep and shallow portions of the Tierra Oscura reef from ~1600 to 1200 years BP, corroborating the model of worsening DO concentrations at this reef (Fig. 2).…”

Section: Discussionsupporting

confidence: 67%

Millennial‐scale change on a Caribbean reef system that experiences hypoxia

et al. 2021

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Coastal hypoxia has become an increasingly acknowledged threat to coral reefs that is potentially intensifying because of increased input of anthropogenic nutrients. Almirante Bay (Caribbean Panama) is a semi‐enclosed system that experiences hypoxia in deeper waters which occasionally shoals onto shallow coral reefs, suffocating most aerobic benthic life. To explore the long‐term history of reefs in the bay we extracted reef matrix cores from two reefs that today experience contrasting patterns of oxygenation. We constructed a 1800‐year‐long record of gastropod assemblages and isotope compositions from six U‐Th chronologically‐constrained reef matrix cores. We extracted two cores from each reef at 3 m water depth and two additional cores from a deeper part (4.8 m) of the hypoxia‐exposed reef. Results show that the deeper part of the hypoxic reef slowed in growth and stopped accreting approximately 1500 years BP while the shallow part of the reef continued to accrete to the present day, in agreement with a model of expanding hypoxia at this time. Our proxy‐based approach suggests that the patterns of increasing herbivores and decreasing carbon isotope values in the deeper part of the hypoxic reef may have been driven by an increase in hypoxia via eutrophication caused by either natural changes or human impacts. Similar patterns in these paleoindicators occurred in the shallow part of the hypoxic reef during the last few decades. This suggests that the deep water hypoxia may be expanding to depths as shallow as 3 m and that shallow reefs are at greater risk due to increased human activity.

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Section: Discussionsupporting

confidence: 67%

Millennial‐scale change on a Caribbean reef system that experiences hypoxia

et al. 2021

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“…Some gastropod taxa and functional groups also provide evidence of historical increases of hypoxic conditions. For example, the decline in the relative abundance of Anachis, a genus that is particularly sensitive to hypoxic conditions (Díaz Asencio et al 2016, Kuk-Dzul andDíaz-Castañeda 2016), in the deep and shallow portions of the Tierra Oscura reef from ~1600-1200 yrs BP corroborates the model of worsening DO concentrations at this reef (Fig. 2).…”

Section: Signs Of Deterioration In Coral Reef Conditionsupporting

confidence: 58%

Millennial-scale change on a Caribbean reef system that experiences hypoxia

Figuerola

Grossman

Lucey

et al. 2021

Preprint

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Coastal hypoxia has become an increasingly acknowledged threat to coral reefs that is potentially intensifying because of increased input of anthropogenic nutrients. Almirante Bay (Caribbean Panama) is a semi-enclosed system that experiences hypoxia in deeper waters which occasionally expand into shallow coral reefs, suffocating most aerobic benthic life. To explore the long-term history of reefs in the bay we extracted reef matrix cores from two reefs that today experience contrasting patterns of oxygenation. We constructed a 1800-year-long record of gastropod assemblages and isotope compositions from six U-Th chronologically-constrained reef matrix cores. We extracted two cores from each reef at 3 m water depth and two additional cores from a deeper part (4.8 m) of the hypoxia-exposed reef. Results show that the deeper part of the hypoxic reef slowed in growth and stopped accreting approximately 1500 years BP while the shallow part of the reef continued to accrete to the present day, in agreement with a model of expanding hypoxia at this time. Our proxy-based approach suggests that differences among these palaeoindicators in the two reefs may have been driven by an increase in hypoxia via eutrophication caused by either natural changes or human impacts. Similar patterns of increasing herbivores and decreasing carbon isotope values occurred in the shallow part of the hypoxic reef during the last few decades. This suggests that hypoxia may be expanding to depths as shallow as 3 m and that shallow reefs are experiencing greater risk due to increased human activity.

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“…Physicochemical Parameters. Physicochemical parameters recorded in Table 1 did not show a signifcant variation, where the recorded temperature ranged between 12 °C and 19 °C, salinity ranged between 33.91 psu to 35.45 psu, and dissolved oxygen between 0.71 and 2.96 ppm showing prevailing hypoxic conditions, which are often associated with pollution due to anthropogenic activities [26]. Seawater temperature, salinity, pH, dissolved oxygen, turbidity, and organic matter become water quality stressors when available in excessive amounts [27].…”

Section: Resultsmentioning

confidence: 92%

The Prevalence of Bacteria Commonly Related to the Production of Mussels and Oysters in Saldanha Bay

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Human

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et al. 2023

Aquaculture Research

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Bivalve molluscs are a good source of high quality protein and perform important ecological functions. Their ability to bioaccumulate materials in their soft tissues makes them suitable aquatic species for biomonitoring of environmental conditions. The discharge of treated and untreated sewage into the bivalve-growing areas is a concern. The aim of this study was to investigate the prevalence of bacterial microbiota in shellfish farms in Saldanha Bay harbour using pathogens commonly associated with shellfish-related foodborne disease outbreaks. Seawater and mussel samples were collected from five sampling points located in three sampling locations. Oyster samples were collected from the harbour deck immediately after harvesting by the farmers. The most probable number (MPN) method was used to enumerate E. coli and faecal coliforms. Cultural methods were used for the detection of Salmonella and Vibrio spp. The E. coli concentrations for 15 March and 14 July are <0.18 MPN/100 ml at all sampling sites and for 25 August, <0.18 MPN/100 ml for all sampling sites except sampling site SP2 (0.2 MPN/100 ml). Spikes were observed on the total MPN counts in winter. Salmonella and Vibrio spp. were not detected. However, other bacterial species were identified through their phenotypic profile using the VITEK 2 system. Based on the low E. coli-MPN concentrations, the study concluded that the molluscs were safe for human consumption. Further studies need to be conducted on the bacterial species identified.

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The Relationship between Mollusks and Oxygen Concentrations in Todos Santos Bay, Baja California, Mexico

Cited by 9 publications

References 46 publications

Millennial‐scale change on a Caribbean reef system that experiences hypoxia

Millennial‐scale change on a Caribbean reef system that experiences hypoxia

Millennial-scale change on a Caribbean reef system that experiences hypoxia

The Prevalence of Bacteria Commonly Related to the Production of Mussels and Oysters in Saldanha Bay

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