publication – Page 3 – Laboratoire LEMAR UMR 6539

Marine invertebrates and noise

Abstract

Within the set of risk factors that compromise the conservation of marine biodiversity, one of the least understood concerns is the noise produced by human operations at sea and from land. Many aspects of how noise and other forms of energy may impact the natural balance of the oceans are still unstudied. Substantial attention has been devoted in the last decades to determine the sensitivity to noise of marine mammals—especially cetaceans and pinnipeds—and fish because they are known to possess hearing organs. Recent studies have revealed that a wide diversity of invertebrates are also sensitive to sounds, especially via sensory organs whose original function is to allow maintaining equilibrium in the water column and to sense gravity. Marine invertebrates not only represent the largest proportion of marine biomass and are indicators of ocean health but many species also have important socio-economic values. This review presents the current scientific knowledge on invertebrate bioacoustics (sound production, reception, sensitivity), as well as on how marine invertebrates are affected by anthropogenic noises. It also critically revisits the literature to identify gaps that will frame future research investigating the tolerance to noise of marine ecosystems.

Figure 4 : Marine Invertebrate sound sensory systems.

Highlights

(1) We reported on the current scientific knowledge on marine invertebrate bioacoustics (detection and production of sound) and their responses (physical, physiological and behavioural effects) to anthropogenic noise at different life stages, population and ecosystem levels. Although the impact of noise pollution in marine invertebrates is understudied, an exhaustive and systematic revision of literature provided evidence that anthropogenic noise is detrimental not only to these species but also to the natural ecosystems they inhabit.

(2) Considering that the effects of noise can be elicited from cellular to ecosystems level, the understanding of noise impact requires an interdisciplinary expertise to embrace a holistic vision of the problem.

(3) Further research must include a detailed protocol that would ideally provide not only accurate acoustic metrics and methods, but also long-term experiments, cumulative effects, gradients of noise exposure, potential recovery from chronic noise in a variety of taxonomic groups and noise sources.

(4) Multiple stressors effects have to be considered when assessing potential impacts of noise exposure.

(5) This review represents a valuable reference to provides guidance to natural resource managers when evaluating anthropogenic noise effects and developing future operations at temporal and spatial scales that are relevant to oceanic ecosystems.

Reference

Sole´ M, Kaifu K, Mooney TA, Nedelec SL, Olivier F, Radford AN, Vazzana M, Wale MA, Semmens JM, Simpson SD, Buscaino G, Hawkins A, Aguilar de Soto N, Akamatsu T, Chauvaud L, Day RD, Fitzgibbon Q, McCauley RD and Andre´ M. (2023) Marine invertebrates and noise. Front. Mar. Sci. 10:1129057. doi: 10.3389/fmars.2023.1129057

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26/04/2023/by sherve@univ-brest.fr

The unaccounted dissolved iron (II) sink: Insights from dFe(II) concentrations in the deep Atlantic Ocean

article of the month

Abstract

Hydrothermal vent sites found along mid-ocean ridges are sources of numerous reduced chemical species and trace elements. To establish dissolved iron (II) (dFe(II)) variability along the Mid Atlantic Ridge (between 39.5°N and 26°N), dFe(II) concentrations were measured above six hydrothermal vent sites, as well as at stations with no active hydrothermal activity. The dFe(II) concentrations ranged from 0.00 to 0.12 nmol L−1 (detection limit = 0.02 ± 0.02 nmol L−1) in non-hydrothermally affected regions to values as high as 12.8 nmol L−1 within hydrothermal plumes. Iron (II) in seawater is oxidised over a period of minutes to hours, which is on average two times faster than the time required to collect the sample from the deep ocean and its analysis in the onboard laboratory. A multiparametric equation was used to estimate the original dFe(II) concentration in the deep ocean. The in-situ temperature, pH, salinity and delay between sample collection and its analysis were considered. The results showed that dFe(II) plays a more significant role in the iron pool than previously accounted for, constituting a fraction >20 % of the dissolved iron pool, in contrast to <10 % of the iron pool formerly reported. This discrepancy is caused by Fe(II) loss during sampling when between 35 and 90 % of the dFe(II) gets oxidised. In-situ dFe(II) concentrations are therefore significantly higher than values reported in sedimentary and hydrothermal settings where Fe is added to the ocean in its reduced form. Consequently, the high dynamism of dFe(II) in hydrothermal environments masks the magnitude of dFe(II) sourced within the deep ocean.

Highlights

Considering oxidation, open ocean iron (II) concentrations are below 0.2 nmol L⁻¹.
The highest measured iron (II) concentration was 69.6 nmol L⁻¹ at the Rainbow vent.
In the open ocean iron (II) account for 20 % of the dissolved iron pool.
Oxygen variations within OMZ account for 60 % of iron(II) oxidation variability.

Reference

Gonzalez-Santana, D.; Lough, A. J. M.; Planquette, H.; Sarthou, G.; Tagliabue, A.; Lohan, M. C. The Unaccounted Dissolved Iron (II) Sink: Insights from DFe(II) Concentrations in the Deep Atlantic Ocean. Sci. Total Environ. 2023, 862, 161179.

https://doi.org/10.1016/j.scitotenv.2022.161179.

10/03/2023/by sherve@univ-brest.fr

Spatial distribution of tropical fish assemblages

article of the month

Comprehensive spatial distribution of tropical fish assemblages from multifrequency acoustics and video fulfils the island mass effect framework.

Describing fish distribution and associated environmental features is the first step toward understanding how fish communities are spatially structured and is a necessary step to conduct Marine Spatial Planning (MSP) and operate relevant protection policies.

Abstract

Tropical marine ecosystems are highly biodiverse and provide resources for small-scale fisheries and tourism. However, precise information on fish spatial distribution is lacking, which limits our ability to reconcile exploitation and conservation. We combined acoustics to video observations to provide a comprehensive description of fish distribution in a typical tropical environment, the Fernando de Noronha Archipelago (FNA) off Northeast Brazil. We identified and classified all acoustic echoes into ten fish assemblage and two triggerfish species. This opened up the possibility to relate the different spatial patterns to a series of environmental factors and the level of protection. We provide the first biomass estimation of the black triggerfish Melichthys niger, a key tropical player. By comparing the effects of euphotic and mesophotic reefs we show that more than the depth, the most important feature is the topography with the shelf-break as the most important hotspot. We also complete the portrait of the island mass effect revealing a clear spatial dissymmetry regarding fish distribution. Indeed, while primary productivity is higher downstream, fish concentrate upstream. The comprehensive fish distribution provided by our approach is directly usable to implement scientific-grounded Marine Spatial Planning..

Synthetic representation of the island mass effect as illustrated by the case of Fernando de Noronha.

Reference

Salvetat, J., Bez, N., Habasque, J., Lebourges-Dhaussy, A., Lopes, C., Roudaut, G., Simier, M., Travassos, P., Vargas, G., and Bertrand, A. 2022. Comprehensive spatial distribution of tropical fish assemblages from multifrequency acoustics and video fulfils the island mass effect framework. Scientific Reports 12(1): 8787. Nature Portfolio, Berlin. doi:10.1038/s41598-022-12409-9.

Link to the journal website.

10/06/2022/by titodemora

Immune defense response of the king scallop

article of the month

(c) Gert Hansen - Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License

Abstract

The king scallop, Pecten maximus is a highly valuable seafood in Europe. Over the last few years, its culture has been threatened by toxic microalgae during harmful algal blooms, inducing public health concerns. Indeed, phycotoxins accumulated in bivalves can be harmful for human, especially paralytic shellfish toxins (PST) synthesized by the microalgae Alexandrium minutum. Deleterious effects of these toxic algae on bivalves have also been reported. However, its impact on bivalves such as king scallop is far from being completely understood. This study combined ecophysiological and proteomic analyzes to investigate the early response of juvenile king scallops to a short term exposure to PST producing A. minutum. Our data showed that all along the 2-days exposure to A. minutum, king scallops exhibited transient lower filtration and respiration rates and accumulated PST. Significant inter-individual variability of toxin accumulation potential was observed among individuals. Furthermore, we found that ingestion of toxic algae, correlated to toxin accumulation was driven by two factors: 1/ the time it takes king scallop to recover from filtration inhibition and starts to filtrate again, 2/ the filtration level to which king scallop starts again to filtrate after inhibition. Furthermore, at the end of the 2-day exposure to A. minutum, proteomic analyzes revealed an increase of the killer cell lectin-like receptor B1, involved in adaptative immune response. Proteins involved in detoxification and in metabolism were found in lower amount in A. minutum exposed king scallops. Proteomic data also showed differential accumulation in several structure proteins such as β-actin, paramyosin and filamin A, suggesting a remodeling of the mantle tissue when king scallops are subjected to an A. minutum exposure.

Toxin accumulation linked to feeding behavior. (a). Individual toxin concentration in scallop digestive gland (DG) at the end of the exposure (day 4, μg STX 100 g−1 DG) against the total numbers of A. minutum cells consumed for each scallop on days 3&4 per g of scallop (number of cells g−1) for all assays (n=18). The line indicates the adjusted type II regression model. (b). Graph shows clearance rates (L h−1) from TC-A assays (days 1&2 exposition to T. lutea and C. muelleri and days 3&4 exposition to A. minutum) measured from day 1 to day 4 and standardized for a 7g scallop in total mass. Data have been highlighted according to the 3 clusters (low, medium and high accumulation potential), each empty shape representing an individual from the low □, mean △ or high ○ accumulation cluster and filled shapes corresponding to the average values for 5h from the low ■, mean ▲ and high ●.

Highlights

Harmful microalgae A. minutum transiently inhibits king scallop filtration and respiration activities.
The A. minutum paralytic shellfish toxin accumulation in king scallop is highly variable between individuals.
Proteomic analysis of toxic algae A. minutum effect on king scallop: immune response and detoxication.

Reference

Even, Y., Pousse, E., Chapperon, C., Artigaud, S., Hegaret, H., Bernay, B., Pichereau, V., Flye-Sainte-Marie, J., and Jean, F. 2022. Physiological and comparative proteomic analyzes reveal immune defense response of the king scallop Pecten maximus in presence of paralytic shellfish toxin (PST) from Alexandrium minutum. Harmful Algae 115: 102231. doi:10.1016/j.hal.2022.102231.

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19/05/2022/by titodemora

Influence of strong iron-binding ligands on cloud water oxidant capacity

article of the month

Abstract

Iron (Fe) plays a dual role in atmospheric chemistry: it is involved in chemical and photochemical reactivity and serves as a micronutrient for microorganisms that have recently been shown to produce strong organic ligands. These ligands control the reactivity, mobility, solubility and speciation of Fe, which have a potential impact on Fe bioavailability and cloud water oxidant capacity.

In this work, the concentrations of Fe-binding ligands and the conditional stability constants were experimentally measured for the first time by Competitive Ligand Exchange-Adsorptive Cathodic Stripping Voltammetry (CLE-ACSV) technique in cloud water samples collected at puy de Dôme (France). The conditional stability constants, which indicate the strength of the Fe-ligand complexes, are higher than those considered until now in cloud chemistry (mainly Fe-oxalate). To understand the effect of Fe complexation on cloud water reactivity, we used the CLEPS cloud chemistry model. According to the model results, we found that Fe complexation impacts the hydroxyl radical formation rate: contrary to our expectations, Fe complexation by natural organic ligands led to an increase in hydroxyl radical production. These findings have important impacts on cloud chemistry and the global iron cycle.

Highlights

95% of iron is complexed by strong organic ligands, likely produced by microorganisms.
Fe complexes stability constants are much higher than those used in cloud chemistry.
The presence of strong organic ligands induces an increase in hydroxyl radical production.
The analysis of sources and sinks of radical dotOH highlighted that complexed iron does not deplete HO₂/O₂−radical dot.

Reference

Aridane G. González, Angelica Bianco, Julia Boutorh, Marie Cheize, Gilles Mailhot, Anne-Marie Delort, Hélène Planquette, Nadine Chaumerliac, Laurent Deguillaume, Geraldine Sarthou. Influence of strong iron-binding ligands on cloud water oxidant capacity, Science of The Total Environment, Volume 829, 2022, 154642, ISSN 0048-9697, https://doi.org/10.1016/j.scitotenv.2022.154642.

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30/03/2022/by sherve@univ-brest.fr