Allometry and the calculation of zooplankton metabolism in the subarctic Northeast Pacific Ocean

Maas, Amy E.; Miccoli, Andrea; Stamieszkin, Karen; Carlson, Craig A.; Steinberg, Deborah K.

doi:10.1093/plankt/fbab026

Cited by 14 publications

(19 citation statements)

References 56 publications

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“…Diel vertical migration likely contributes a considerable fraction of global carbon export out of the EZ (Archibald et al, 2019), but the amount of POC consumed by zooplankton in the EZ that is subsequently egested as fecal pellets at depth is poorly constrained (Maas et al, 2021). Indeed, the amount of POC exported out of the EZ by DVM is highly variable and depends on many factors including zooplankton community composition as well as food lability and availability (Steinberg and Landry, 2017).…”

Section: Introductionmentioning

confidence: 99%

Particle cycling rates at Station P as estimated from the inversion of POC concentration data

Amaral

Lam

Marchal

et al. 2022

Elementa: Science of the Anthropocene

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Particle cycling rates in marine systems are difficult to measure directly, but of great interest in understanding how carbon and other elements are distributed throughout the ocean. Here, rates of particle production, aggregation, disaggregation, sinking, remineralization, and transport mediated by zooplankton diel vertical migration were estimated from size-fractionated measurements of particulate organic carbon (POC) concentration collected during the NASA EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) cruise at Station P in summer 2018. POC data were combined with a particle cycling model using an inverse method. Our estimates of the total POC settling flux throughout the water column are consistent with those derived from thorium-234 disequilibrium and sediment traps. A budget for POC in two size fractions, small (1–51 µm) and large (> 51 µm), was produced for both the euphotic zone (0–100 m) and the upper mesopelagic zone (100–500 m). We estimated that POC export at the base of the euphotic zone was 2.2 ± 0.8 mmol m−2 d−1, and that both small and large particles contributed considerably to the total export flux along the water column. The model results indicated that throughout the upper 500 m, remineralization leads to a larger loss of small POC than does aggregation, whereas disaggregation results in a larger loss of large POC than does remineralization. Of the processes explicitly represented in the model, zooplankton diel vertical migration is a larger source of large POC to the upper mesopelagic zone than the convergence of large POC due to particle sinking. Positive model residuals reveal an even larger unidentified source of large POC in the upper mesopelagic zone. Overall, our posterior estimates of particle cycling rate constants do not deviate much from values reported in the literature, i.e., size-fractionated POC concentration data collected at Station P are largely consistent with prior estimates given their uncertainties. Our budget estimates should provide a useful framework for the interpretation of process-specific observations obtained by various research groups in EXPORTS. Applying our inverse method to other systems could provide insight into how different biogeochemical processes affect the cycling of POC in the upper water column.

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Section: Introductionmentioning

confidence: 99%

Particle cycling rates at Station P as estimated from the inversion of POC concentration data

Amaral

Lam

Marchal

et al. 2022

Elementa: Science of the Anthropocene

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“…The differences in biomass and size spectra between Polar and Atlantic surface waters, as observed in our study, suggest that these measures may become important for studying climate change induced community shifts in the Arctic. Furthermore, it will allow us to estimate biomass and size taxon‐specific respiration rates (Ikeda 2014; Bode et al 2018; Kiko and Hauss 2019; Maas et al 2021b) to assess the role of zooplankton in the pelagic Arctic biogeochemical cycle.…”

Section: Discussionmentioning

confidence: 99%

Testing the usefulness of optical data for zooplankton long‐term monitoring: Taxonomic composition, abundance, biomass, and size spectra from ZooScan image analysis

Cornils

Thomisch

Hase

et al. 2022

Limnology & Ocean Methods

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The pelagic ecosystem of the Arctic Ocean is threatened by severe changes such as the reduction in sea‐ice coverage and increased inflow of warmer Atlantic water. The latter is already altering the zooplankton community, highlighting the need for monitoring studies. It is therefore essential to accelerate the taxonomic identification to speed up sample analysis, and to expand the analysis to biomass and size assessments, providing data for modeling efforts. Our case study in Fram Strait illustrates that image‐based analyses with the ZooScan provide abundance data and taxonomic resolutions that are comparable to microscopic analyses and are suitable for zooplankton monitoring purposes in the Arctic. We also show that image analysis allows to differentiate developmental stages of the key species Calanus spp. and Metridia longa and, thus, to study their population dynamics. Our results emphasize that older preserved samples can be successfully reanalyzed with ZooScan. To explore the applicability of image parameters for calculating total mesozooplankton and Calanus spp. biomasses, we used (1) conversion factors (CFs) translating wet mass to dry mass (DM), and (2) length–mass (LM) relationships. For Calanus spp., the calculated biomass values yielded similar results as direct DM measurements. Total mesozooplankton biomass ranged between 1.6 and 15 (LM) or 2.4 and 21 (CF) g DM m−2, respectively, which corresponds to previous studies in Fram Strait. Ultimately, a normalized biomass size spectra analysis provides 1st insights into the mesozooplankton size structure at different depths, revealing steep slopes in the linear fit in communities influenced by Atlantic water inflow.

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“…Active carbon transport by salps and mesozooplankton undergoing diel vertical migration (DVM) (mg C m −2 d −1 ) included the respiration of CO 2 , the excretion of dissolved organic carbon (DOC), fecal pellet egestion (POC), and predation mortality, while at depth during daylight hours (i.e., postgrazing in surface waters at night). Each of these parameters was calculated by applying published or measured metabolic allometric relationships to salp and other zooplankton biomass from MOCNESS tows (Maas et al., 2021 ) and based on a 14 hr occupation at depth each day by vertical migrators. Detailed methods for active transport calculations can be found in Supporting Information S1 .…”

Section: Methodsmentioning

confidence: 99%

“…Specifically, taxon-specific fecal pellet production experiment data, which were also used in conjunction with biomass data to calculate salp fecal pellet contributions, can be found at https://oceandata.sci.gsfc.nasa.gov/ ob/getfile/472d31b192_EXPORTS_NP_species_fecalpellet_production_experimental_R3.sb. Validation of the dissolved organic carbon and respiratory allometric equations is documented in Maas et al (2021). The MOCNESS tow and zooplankton biomass data, used to determine depth-discrete, diel vertical distribution and calculate the active and passive flux of the mesozooplankton and salps can be found at https://oceandata.sci.…”

Section: Data Availability Statementmentioning

confidence: 99%

“…Validation of the dissolved organic carbon and respiratory allometric equations is documented in Maas et al. ( 2021 ). The MOCNESS tow and zooplankton biomass data, used to determine depth‐discrete, diel vertical distribution and calculate the active and passive flux of the mesozooplankton and salps can be found at https://oceandata.sci.gsfc.nasa.gov/ob/getfile/472d31b192_EXPORTS-EXPORTSNP_mocness_process_20191029_R3.sb .…”

Section: Data Availability Statementmentioning

confidence: 99%

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The Outsized Role of Salps in Carbon Export in the Subarctic Northeast Pacific Ocean

Steinberg

Stamieszkin

Maas

et al. 2022

Global Biogeochemical Cycles

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Periodic blooms of salps (pelagic tunicates) can result in high export of organic matter, leading to an “outsized” role in the ocean's biological carbon pump (BCP). However, due to their episodic and patchy nature, salp blooms often go undetected and are rarely included in measurements or models of the BCP. We quantified salp‐mediated export processes in the northeast subarctic Pacific Ocean in summer of 2018 during a bloom of Salpa aspera. Salps migrated from 300 to 750 m during the day into the upper 100 m at night. Salp fecal pellet production comprised up to 82% of the particulate organic carbon (POC) produced as fecal pellets by the entire epipelagic zooplankton community. Rapid sinking velocities of salp pellets (400–1,200 m d−1) and low microbial respiration rates on pellets (<1% of pellet C respired day−1) led to high salp pellet POC export from the euphotic zone‐up to 48% of total sinking POC across the 100 m depth horizon. Salp active transport of carbon by diel vertical migration and carbon export from sinking salp carcasses was usually <10% of the total sinking POC flux. Salp‐mediated export markedly increased BCP efficiency, increasing by 1.5‐fold the proportion of net primary production exported as POC across the base of the euphotic zone and by 2.6‐fold the proportion of this POC flux persisting 100 m below the euphotic zone. Salps have unique and important effects on ocean biogeochemistry and, especially in low flux settings, can dramatically increase BCP efficiency and thus carbon sequestration.

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Allometry and the calculation of zooplankton metabolism in the subarctic Northeast Pacific Ocean

Cited by 14 publications

References 56 publications

Particle cycling rates at Station P as estimated from the inversion of POC concentration data

Particle cycling rates at Station P as estimated from the inversion of POC concentration data

Testing the usefulness of optical data for zooplankton long‐term monitoring: Taxonomic composition, abundance, biomass, and size spectra from ZooScan image analysis

The Outsized Role of Salps in Carbon Export in the Subarctic Northeast Pacific Ocean

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