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Shortcomings of the dissipation rate for understanding the turbulent environment of plankton—And a potential solution 耗散率在了解浮游生物湍流环境方面的不足--以及潜在的解决方案

Limnology and Oceanography Pub Date : 2024-02-12 DOI: 10.1002/lno.12501

Peter J. S. Franks, Bryce G. Inman

{"title":"Shortcomings of the dissipation rate for understanding the turbulent environment of plankton—And a potential solution","authors":"Peter J. S. Franks, Bryce G. Inman","doi":"10.1002/lno.12501","DOIUrl":"https://doi.org/10.1002/lno.12501","url":null,"abstract":"Fundamental marine ecosystem dynamics such as mating, predation, and infection require individual plankton to move relative to one another. Ambient turbulence is often invoked as a mechanism to facilitate such interactions. The local intensity of turbulence is quantified as the dissipation rate of turbulent kinetic energy. While the dissipation rate is central to understanding large‐scale fluxes of heat, salt, and nutrients in the ocean, we show that it can be a poor descriptor of the turbulent environment experienced by individual plankton. A dissipation rate is a single integrated quantity representing all the complex motions in a turbulent region; the instantaneous turbulent environment of plankton may bear little resemblance to that predicted by the dissipation rate or quantities derived from it. Most importantly, the statistics (probabilities) of the relative motions of plankton in turbulence cannot be recovered from the dissipation rate or its spectrum: the probabilities of the plankton experiencing any given turbulent relative velocity are lost in the calculation. This presents a fundamental barrier to our understanding of the effects of ambient turbulence on planktonic ecosystem dynamics in the ocean. Rather than relying on dissipation rates, we show that quantifying the probability distributions of the microscale turbulent motions can provide much richer insights into the turbulent environment of individual plankton. Expanding such statistical analyses, and improving our understanding of the Lagrangian properties of ocean turbulence as experienced by plankton in the ocean will lead to significant increases in our ability to understand and quantify the effects of turbulence on plankton.","PeriodicalId":508819,"journal":{"name":"Limnology and Oceanography","volume":"203 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139843061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Oxygen dynamics in a deep‐silled fjord: Tight coupling to the open shelf 深溢峡湾的氧气动力学：与开放陆架的紧密耦合

Limnology and Oceanography Pub Date : 2024-02-08 DOI: 10.1002/lno.12522

Charles G. Hannah, Sophia C. Johannessen, Cynthia A. Wright, Stephen J. Page

{"title":"Oxygen dynamics in a deep‐silled fjord: Tight coupling to the open shelf","authors":"Charles G. Hannah, Sophia C. Johannessen, Cynthia A. Wright, Stephen J. Page","doi":"10.1002/lno.12522","DOIUrl":"https://doi.org/10.1002/lno.12522","url":null,"abstract":"Oxygen is declining globally in subsurface seawater. Fjords are particularly susceptible to hypoxia, because entrance sills restrict water circulation. We studied the oxygen dynamics of the Kitimat Fjord System on the west coast of Canada, using 3 yr of data from moored sensors and water column profiles. Subsurface oxygen within the fjord system is principally controlled by the connection to Hecate Strait on the outer shelf. Variations in oxygen concentration in Hecate Strait are reflected in the water that is drawn into the fjord system year‐round at mid‐depth (50–150 m). Deep water is renewed annually, beginning in May/June. Remineralization results in a seasonal decline in oxygen at depth. In the absence of deep‐water renewal, the bottom water in the system could become hypoxic in 1–2 yr. Mixing over a shallow inner sill (100 m) replenishes the oxygen in the deep water of Gardner Canal year‐round. The decadal trends in oxygen concentration show an increase from the 1950s to a maximum in the late 1970s, followed by a decline through 2016. The decline over the period 1977–2016 is 0.018 mL L−1 yr−1 (~ 0.83 μmol L−1 yr−1), which is consistent with the decline observed over the upper continental shelf over the same period.","PeriodicalId":508819,"journal":{"name":"Limnology and Oceanography","volume":"62 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139850684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0