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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Marine Biogeochemistry
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1469587

Respiration rates and its relationship with ETS activity in Euphausiids: Implications for active flux estimations

Provisionally accepted
María Couret María Couret 1*Javier Díaz-Pérez Javier Díaz-Pérez 1Airam N. Sarmiento-Lezcano Airam N. Sarmiento-Lezcano 1,2Jose M. Landeira Jose M. Landeira 1Santiago Hernández-León Santiago Hernández-León 1
  • 1 Instituto de Oceanografía y Cambio Global (IOCAG), Las Palmas de Gran Canaria, Spain
  • 2 Centro Oceanográfico de A Coruña, A Coruña, Spain

The final, formatted version of the article will be published soon.

    Euphausiids, commonly known as krill, are crucial contributors to the ocean's active carbon pump, impacting carbon export and sequestration through their diel vertical migration. These organisms feed on organic matter in the epipelagic layer at night and release inorganic carbon in the mesopelagic layer during the day via respiration. Measuring respiration in the mesopelagic layer is challenging due to the difficulties in obtaining direct measurements, as well as the lack of comprehensive data, and reliance on conservative estimates. The measurement of the electron transfer system (ETS) activity is used as a proxy to assess respiration in the mesopelagic layer. However, accurate calibration of respiration rates and ETS activity is imperative through experimental measurements and empirical data. Here, we compared the respiration rates with their respective ETS activities of different species of euphausiids captured at night in the epipelagic layer of the Atlantic Ocean along a latitudinal (42-29°N, 25°W) and a longitudinal (25-13°W, 29°N) transect. Our results revealed a spatial trend in respiration rates, and consequently in ETS activities, with rates decreasing southward and increasing slightly towards the African upwelling region. The Generalized Additive Model (GAM) demonstrated that epipelagic oxygen concentration, chlorophyll a, and the interaction between epipelagic temperature and mesopelagic oxygen concentration significantly influenced euphausiids respiration rates. Furthermore, we observed a strong correlation between respiration and specific ETS activities, with R/ETS ratios exceeding the conservative value of 0.5, which is typically used to estimate respiratory flux.

    Keywords: euphausiids, Respiration rates, specific ETS activity, R/ETS ratio, Vertical migration, active carbon pump

    Received: 24 Jul 2024; Accepted: 16 Sep 2024.

    Copyright: © 2024 Couret, Díaz-Pérez, Sarmiento-Lezcano, Landeira and Hernández-León. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: María Couret, Instituto de Oceanografía y Cambio Global (IOCAG), Las Palmas de Gran Canaria, Spain

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