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Pearl Farming Micro-Nanoplastics Affect Oyster Physiology and Pearl Quality

Abstract

Pearl farming is crucial for the economy of French Polynesia. However, rearing structures contribute significantly to plastic waste, and the widespread contamination of pearl farming lagoons by microplastics has raised concerns about risks to the pearl industry. This study aimed to evaluate the effects of micro-nanoplastics (MNPs, 0.4–200 μm) on the pearl oyster (Pinctada margaritifera) over a 5-month pearl production cycle by closely mimicking ecological scenarios. MNPs were produced from weathered plastic pearl farming gear and tested at environmentally relevant concentrations (0.025 and 1 μg L–1) to decipher biological and functional responses through integrative approaches. The significant findings highlighted the impacts of MNPs on oyster physiology and pearl quality, even at remarkably low concentrations. Exposure to MNPs induced changes in energy metabolism, predominantly driven by reduced assimilation efficiency of microalgae, leading to an alteration in gene expression patterns. A distinct gene expression module exhibited a strong correlation with physiological parameters affected by MNP conditions, identifying key genes as potential environmental indicators of nutritional-MNP stress in cultured oysters. The alteration in pearl biomineralization, evidenced by thinner aragonite crystals and the presence of abnormal biomineral concretions, known as keshi pearls, raises concerns about the potential long-term impact on the Polynesian pearl industry.

 

Graphical abstract


 

Keywords
Pearl ; oyster ; micro-nanoplastic exposure ; environmental scenarios ; ecophysiology ; energy metabolism ; functional genomics ; pearl cycle

Reference
Gardon, Tony, Jeremy Le Luyer, Gilles Le Moullac, Claude Soyez, Fabienne Lagarde, Alexandre Dehaut, Ika Paul-Pont, et Arnaud Huvet. « Pearl Farming Micro-Nanoplastics Affect Oyster Physiology and Pearl Quality ». ENVIRONMENTAL SCIENCE & TECHNOLOGY 58, no 1 (9 janvier 2024): 207‑18. https://doi.org/10.1021/acs.est.3c06684.

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Expé-1point5 publication in “One Earth”

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Here is a link to a publication by Olivier Ragueneau and Audrey Sabbagh, published on May 17 in the journal “One Earth.” It describes the philosophy and objectives of the experiment that has been co-led since 2020 by LEMAR (IUEM) and UMR MERIT (Université Paris Cité) as part of the Labos 1point5 collective. The Expé-1point5 aims to stimulate changes in laboratory research practices to reduce their greenhouse gas (GHG) emissions. As its title suggests, “From carbon to meaning,” it goes beyond the climate perspective to question the very meaning of our research activities under climate constraints: is it possible to maintain high-quality research, and even increase it, notably through the idea of ​​slow science, while reducing GHG emissions and improving the quality of life at work? The idea of ​​this article is to propose making research a transformation demonstrator to achieve environmentally and socially sustainable research.

Enjoy the reading!

Read the article:
“From carbon to meaning: Experimenting for sustainable science”

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Hydrothermal mercury: the natural history of a contaminant

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Our colleague Hélène Planquette participated in an international study coordinated by the CNRS aiming to estimate the contribution of hydrothermal sources to the mercury stock present in the oceans.

This study has just been published in the journal Nature Geoscience and is the subject of a CNRS press release:

An international team of researchers, coordinated by the CNRS (see inset), has established the first global estimate of hydrothermal mercury (Hg) emissions from mid-ocean ridges. The UN Minamata Convention on Mercury aims to reduce human exposure to toxic mercury by reducing anthropogenic emissions. We are primarily exposed through the consumption of fish that bioaccumulate Hg from the ocean. The current paradigm is that anthropogenic mercury emissions (currently 3,100 tons per year) are responsible for a 21% increase in the global oceanic mercury reservoir. This estimate is inaccurate because we do not know how much natural mercury was present in the ocean before the start of anthropogenic emissions.

We are also unable to quantify the impact of anthropogenic emissions on Hg levels in fish. Hydrothermalism is the only direct source of natural Hg to the ocean. Previous studies, based solely on hydrothermal fluid measurements, suggested that hydrothermal Hg inputs could range from 20 to 2,000 tons per year. This new study used measurements of hydrothermal plumes, seawater, and rock cores in addition to fluid measurements from the Trans-Atlantic Geotraverse (TAG) hydrothermal source on the Mid-Atlantic Ridge.

The combination of observations suggests that the majority of enriched Hg in the fluids would be diluted in seawater, and a small fraction would precipitate locally. Extrapolation of the results indicates that the overall hydrothermal Hg flux from mid-ocean ridges is low (1.5 to 65 tons per year) compared to anthropogenic Hg emissions. Although this suggests that the majority of Hg in the ocean is of anthropogenic origin, it also raises hope that strict implementation of emission reductions under the Minamata Convention will reduce mercury levels in fish and human exposure.

 

Article Reference:

Torres-Rodriguez, N., Yuan, J., Petersen, S. et al. Mercury fluxes from hydrothermal venting at mid-ocean ridges constrained by measurements. Nat. Geosci. (2023).

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The ocean may be storing more carbon than estimated in previous studies

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Our colleague Frédéric Le Moigne contributed to an international study on the efficiency of the oceanic carbon pump. The study, published this week in Nature magazine, reassesses the ocean’s capacity to store carbon, particularly through ‘marine snow’. The CNRS issued a press release about this publication :

The ocean’s capacity to store atmospheric carbon dioxide is almost 20% higher than the estimates presented in the latest IPCC report. These are the findings of a study published in the journal Nature on 6 December 2023 by an international team including a biologist from the CNRS. The scientists looked at the role played by plankton in the natural transport of carbon from the surface to the seabed.

Plankton is fond of this gas, which it transforms into organic tissue through photosynthesis during its development, and some of it is transformed into marine particles at the end of its life. Denser than seawater, this ‘marine snow’ sinks to the seabed, storing carbon and providing essential nutrients for many deep-sea creatures, from tiny bacteria to deep-sea fish.

Based on the study of a database collected from around the world since the 1970s using oceanographic vessels, the team of seven scientists were able to digitally map the fluxes of organic matter throughout the oceans. The resulting new estimate of storage capacity is 15 gigatonnes per year, an increase of around 20% on the previous studies (11 gigatonnes per year) reported by the IPCC in its 2021 report.

This reassessment of the seabed’s storage capacity represents a significant advance in our understanding of carbon exchanges between the atmosphere and the ocean at a global level. While the team stresses that this absorption process takes place over tens of thousands of years, and is therefore not sufficient to offset the exponential increase in CO2 emissions generated by global industrial activity since 1750, this study nevertheless reinforces the importance of the ocean ecosystem as a major player in regulating the global climate in the long term.

Global distribution of organic carbon flux from the surface layer of the open ocean.
© Wang et al., 2023, Nature.

 

Reference:

Biological carbon pump estimate based on multi-decadal hydrographic data. Wei-Lei Wang, Weiwei Fu, Frédéric A. C. Le Moigne, Robert T. Letscher, Yi Liu, Jin-Ming Tang, and François W. Primeau. Nature, le 6 décembre 2023.
DOI : https://doi.org/10.1038/s41586-023-06772-4

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A critical review on the evaluation of toxicity and ecological risk assessment of plastics in the marine environment

Abstract

The increasing production of plastics together with the insufficient waste management has led to massive pollution by plastic debris in the marine environment. Contrary to other known pollutants, plastic has the potential to induce three types of toxic effects: physical (e.g intestinal injuries), chemical (e.g leaching of toxic additives) and biological (e.g transfer of pathogenic microorganisms). This critical review questions our capability to give an effective ecological risk assessment, based on an ever-growing number of scientific articles in the last two decades acknowledging toxic effects at all levels of biological integration, from the molecular to the population level. Numerous biases in terms of concentration, size, shape, composition and microbial colonization revealed how toxicity and ecotoxicity tests are still not adapted to this peculiar pollutant. Suggestions to improve the relevance of plastic toxicity studies and standards are disclosed with a view to support future appropriate legislation.

 

Graphical Abstract



Highlignts

  • Recurrent toxic effects of plastic debris seen from molecular to population levels.
  • Tested conditions (concentration, type, size, shape) lack environmental relevancy.
  • Environmental studies on plastic debris are scarce.
  • Actual toxicity standards are not adapted to plastic.

Reference

David Leistenschneider, Adèle Wolinski, Jingguang Cheng, Alexandra ter Halle, Guillaume Duflos, Arnaud Huvet, Ika Paul-Pont, Franck Lartaud, François Galgani, Édouard Lavergne, Anne-Leila Meistertzheim, Jean-François Ghiglione, A critical review on the evaluation of toxicity and ecological risk assessment of plastics in the marine environment, Science of The Total Environment, Vol 896, 2023

Read the paper, published in Open Access
https://doi.org/10.1016/j.scitotenv.2023.164955

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