Cordelia Roberts, Clara M. Flintrop, Alexander Khachikyan, Jana Milucka, Colin B. Munn, Morten H. Iversen
{"title":"微塑料可能会降低海洋雪的沉降速度和碳含量,从而降低生物碳泵的效率","authors":"Cordelia Roberts, Clara M. Flintrop, Alexander Khachikyan, Jana Milucka, Colin B. Munn, Morten H. Iversen","doi":"10.1002/lno.12615","DOIUrl":null,"url":null,"abstract":"<p>Plastics are pervasive in marine ecosystems and ubiquitous in both shallow and deep oceans. Microfibers, among other microplastics, accumulate in deep-sea sediments at concentrations up to four orders of magnitude higher than in surface waters. This is at odds with the fact that most microfibers are positively buoyant; therefore, it is hypothesized that settling aggregates are vectors for the downward transport of microfibers in the ocean. However, little is known about the impact of microfibers on carbon export. We formed diatom aggregates with differing concentrations of microfibers using roller tanks and observed that microfiber addition stimulated aggregate formation, but decreased their structural cohesion and caused them to break apart more readily, resulting in smaller average sizes. The incorporation of positively buoyant microfibers into settling aggregates reduced their size-specific sinking velocities proportional to the microfiber concentration. Slower sinking may extend aggregate retention time in the upper ocean, thereby increasing the time available for organic matter remineralization in the upper water column. Here, we show that at concentrations of 10<sup>5</sup> microfibers per cubic meter, microfiber incorporation into settling marine aggregates decreases potential export flux by 8–45%. Microfibers accumulating at such high concentrations, for example, in Arctic sea ice, may, therefore, be substantially reducing the efficiency of the biological carbon pump relative to the pre-plastic era.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":null,"pages":null},"PeriodicalIF":3.8000,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12615","citationCount":"0","resultStr":"{\"title\":\"Microplastics may reduce the efficiency of the biological carbon pump by decreasing the settling velocity and carbon content of marine snow\",\"authors\":\"Cordelia Roberts, Clara M. Flintrop, Alexander Khachikyan, Jana Milucka, Colin B. Munn, Morten H. Iversen\",\"doi\":\"10.1002/lno.12615\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Plastics are pervasive in marine ecosystems and ubiquitous in both shallow and deep oceans. Microfibers, among other microplastics, accumulate in deep-sea sediments at concentrations up to four orders of magnitude higher than in surface waters. This is at odds with the fact that most microfibers are positively buoyant; therefore, it is hypothesized that settling aggregates are vectors for the downward transport of microfibers in the ocean. However, little is known about the impact of microfibers on carbon export. We formed diatom aggregates with differing concentrations of microfibers using roller tanks and observed that microfiber addition stimulated aggregate formation, but decreased their structural cohesion and caused them to break apart more readily, resulting in smaller average sizes. The incorporation of positively buoyant microfibers into settling aggregates reduced their size-specific sinking velocities proportional to the microfiber concentration. Slower sinking may extend aggregate retention time in the upper ocean, thereby increasing the time available for organic matter remineralization in the upper water column. Here, we show that at concentrations of 10<sup>5</sup> microfibers per cubic meter, microfiber incorporation into settling marine aggregates decreases potential export flux by 8–45%. Microfibers accumulating at such high concentrations, for example, in Arctic sea ice, may, therefore, be substantially reducing the efficiency of the biological carbon pump relative to the pre-plastic era.</p>\",\"PeriodicalId\":18143,\"journal\":{\"name\":\"Limnology and Oceanography\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":3.8000,\"publicationDate\":\"2024-08-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12615\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Limnology and Oceanography\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1002/lno.12615\",\"RegionNum\":1,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"LIMNOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Limnology and Oceanography","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/lno.12615","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"LIMNOLOGY","Score":null,"Total":0}
Microplastics may reduce the efficiency of the biological carbon pump by decreasing the settling velocity and carbon content of marine snow
Plastics are pervasive in marine ecosystems and ubiquitous in both shallow and deep oceans. Microfibers, among other microplastics, accumulate in deep-sea sediments at concentrations up to four orders of magnitude higher than in surface waters. This is at odds with the fact that most microfibers are positively buoyant; therefore, it is hypothesized that settling aggregates are vectors for the downward transport of microfibers in the ocean. However, little is known about the impact of microfibers on carbon export. We formed diatom aggregates with differing concentrations of microfibers using roller tanks and observed that microfiber addition stimulated aggregate formation, but decreased their structural cohesion and caused them to break apart more readily, resulting in smaller average sizes. The incorporation of positively buoyant microfibers into settling aggregates reduced their size-specific sinking velocities proportional to the microfiber concentration. Slower sinking may extend aggregate retention time in the upper ocean, thereby increasing the time available for organic matter remineralization in the upper water column. Here, we show that at concentrations of 105 microfibers per cubic meter, microfiber incorporation into settling marine aggregates decreases potential export flux by 8–45%. Microfibers accumulating at such high concentrations, for example, in Arctic sea ice, may, therefore, be substantially reducing the efficiency of the biological carbon pump relative to the pre-plastic era.
期刊介绍:
Limnology and Oceanography (L&O; print ISSN 0024-3590, online ISSN 1939-5590) publishes original articles, including scholarly reviews, about all aspects of limnology and oceanography. The journal''s unifying theme is the understanding of aquatic systems. Submissions are judged on the originality of their data, interpretations, and ideas, and on the degree to which they can be generalized beyond the particular aquatic system examined. Laboratory and modeling studies must demonstrate relevance to field environments; typically this means that they are bolstered by substantial "real-world" data. Few purely theoretical or purely empirical papers are accepted for review.