Benthic oxygen dynamics and implication for the maintenance of chronic hypoxia and ecosystem degradation in the Berre lagoon (France)

Rigaud, Sylvain; Deflandre, Bruno; Grenz, Christian; Cesbron, Florian; Pozzato, Lara; Voltz, Baptiste; Grémare, Antoine; Romero-Ramirez, Alicia; Mirleau, Pascal; Meulé, Samuel; Faure, Vincent; Mayot, Nicolas; Michotey, Valérie; Bonin, Patricia; Pascal, Ludovic; Cordier, Marie-Ange; Lamarque, Bastien; Radakovitch, Olivier

doi:10.1016/j.ecss.2021.107437

Cited by 6 publications

(3 citation statements)

References 32 publications

(35 reference statements)

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“…The sediment of these lagoons, although quite recent, has served as an object of study to understand the changes that have taken place in the last thousands of years, as well as a record of the contamination received from the basin. Among these studies are those of the Albufera of Valencia [57], in which salinity changes in the lagoon are observed, the presence of contaminating metals such as in Bages [58] and Ghar El Melh [59], and the relationship between the conditions of the benthos and hypoxia in the water of the Berre lagoon [60].…”

Section: Discussionmentioning

confidence: 99%

Mediterranean Coastal Lagoons Review: Sites to Visit before Disappearance

Soria

Pérez-González

Sòria‐Perpinyà

2022

JMSE

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Coastal lagoons are an established priority habitat in the European environment because of the biological communities that inhabit them. Their origin is related to the transport of sediments from a nearby river or the movement of sands by the marine currents that produce the closure of a gulf. Therefore, they are recent geological formations, which also disappear quickly if environmental conditions change. The 37 coastal lagoons with a surface area greater than 10 km2 located in the Mediterranean basin have been identified. Fishing has been the traditional use of these lagoons, in addition to their use as a navigation harbor when they are open to the sea. Pollution, quality problems and their consequences are the most studied topics in recent publications. Sentinel-2 images taken in the summer of 2020 have been used to study water transparency, suspended matter and chlorophyll a concentration. The result was that only six of them are in good ecological condition, but most of them are eutrophic due to the impacts on their environment and the inflow of poor quality water. The cultural values of these lagoons must also be protected and preserved.

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Section: Discussionmentioning

confidence: 99%

Mediterranean Coastal Lagoons Review: Sites to Visit before Disappearance

Soria

Pérez-González

Sòria‐Perpinyà

2022

JMSE

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“…Indeed, these features limit our ability to detect potential short and long-term effects of hypoxic stress on macrobenthic communities. Bottom hypoxia/anoxia is also known to predominantly take place in deep lagoons like Berre and Thau (Derolez et al, 2020a; Rigaud et al, 2021; Souchu et al, 1998), where wind derived water mixing is limited by depth. Nonetheless, anoxic crises inside coastal lagoons are expected to increase in frequency and intensity with climate change (Derolez et al, 2020a; Miyamoto et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

“…Oxygen depletion generally takes place during the summer and is maximal at the end of the night/early morning (Newton et al, 2010), often starting near the bottom because of benthic organic matter mineralization ( e.g. sedimented phytoplankton, dead macroalgae) and low water renewal (Rigaud et al, 2021; Souchu et al, 1998). In the worst cases, these low to zero oxygen zones can spread to the entire water column and last for several days (Chapelle et al, 2001; Cladas et al, 2016), as seen during the 2018 dystrophic crisis in Thau lagoon (Derolez et al, 2020a).…”

Section: Discussionmentioning

confidence: 99%

Disentangling the effects of eutrophication and natural variability on macrobenthic communities across French coastal lagoons

Jones

Schaal

Boyé

et al. 2022

Preprint

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Coastal lagoons are transitional ecosystems that host a unique diversity of species and support many ecosystem services. Owing to their position at the interface between land and sea, they are also subject to increasing human impacts, which alter their ecological functioning. Because coastal lagoons are naturally highly variable in their environmental conditions, disentangling the effects of anthropogenic disturbances like eutrophication from those of natural variability is a challenging, yet necessary issue to address. Here, we analyze a dataset composed of macrobenthic invertebrate abundances and environmental variables (hydro-morphology, water, sediment and macrophytes) gathered across 29 Mediterranean coastal lagoons located in France to characterize the main drivers of community composition and structure. Using correlograms, linear models and variance partitioning, we found that lagoon hydro-morphology (connection to the sea and surface) which affects the level of environmental variability (salinity and temperature), as well as lagoon-scale benthic habitat diversity (using macrophyte morphotypes) seemed to regulate macrofauna distribution, while eutrophication and associated stressors like low dissolved oxygen acted upon the existing communities, mainly by reducing species richness and diversity. Furthermore, M-AMBI, a multivariate index composed of species richness, Shannon diversity and AMBI (AZTI's Marine Biotic Index) and currently used to evaluate the ecological state of French coastal lagoons, was more sensitive to eutrophication (18%) than to natural variability (9%) with nonetheless 49% of its variability explained jointly by both. Conversely, AMBI was the only tested index that uniquely responded to eutrophication variables, which nonetheless explained less than a third of its variability. To improve the robustness of benthic indicators like M-AMBI and increase the effectiveness of lagoon benthic habitat management, we call for a revision of the ecological groups at the base of the AMBI index and of the current lagoon typology which could be inspired by the lagoon-sea connection levels used in this study.

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