Azam, F. et al. The ecological role of water-column microbes in the sea. Mar. Ecol. Prog. Ser. 10, 257–263 (1983).
Google Scholar
Legendre, L. & Le Fèvre, J. Microbial food webs and the export of biogenic carbon in oceans. Aquat. Microb. Ecol. 9, 69–77 (1995).
Google Scholar
Legendre, L. & Rivkin, R. B. Planktonic food webs: Microbial hub approach. Mar. Ecol. Prog. Ser. 365, 289–309 (2008).
Google Scholar
Arístegui, J., Gasol, J. M., Duarte, C. M. & Herndl, G. J. Microbial oceanography of the dark ocean’s pelagic realm. Limnol. Oceanogr. 54, 1501–1529 (2009).
Google Scholar
Roshan, S. & DeVries, T. Efficient dissolved organic carbon production and export in the oligotrophic ocean. Nat. Commun. 8, 2036. https://doi.org/10.1038/s41467-017-02227-3 (2017).
Google Scholar
Pauly, D. & Christensen, V. Primary production required to sustain global fisheries. Nature 374, 255–257 (1995).
Google Scholar
Sarmiento, J. L. & Gruber, N. Ocean Biogeochemical Dynamics (Princeton University Press, 2006).
Armengol, L., Calbet, A., Franchy, G., Rodríguez-Santos, A. & Hernández-León, S. Planktonic food web structure and trophic transfer efficiency along a productivity gradient in the tropical and subtropical Atlantic Ocean. Sci. Rep. 9, 2044. https://doi.org/10.1038/s41598-019-38507-9 (2019).
Google Scholar
Hernández-León, S. et al. Large deep-sea zooplankton biomass mirrors primary production in the global ocean. Nat. Commun. 11, 6048. https://doi.org/10.1038/s41467-020-19875-7 (2020).
Google Scholar
Wilson, R. et al. Contribution of fish to the marine inorganic carbon cycle. Science 323, 359–362 (2009).
Google Scholar
Jennings, S. & van der Molen, J. Trophic levels of marine consumers from nitrogen stable isotope analysis: Estimation and uncertainty. ICES J. Mar. Sci. 72, 2289–2300 (2015).
Google Scholar
Jennings, S., Maxwell, T. A. D., Schratzberger, M. & Milligan, S. P. Body-size dependent temporal variations in nitrogen stable isotope ratios in food webs. Mar. Ecol. Prog. Ser. 370, 199–206 (2008).
Google Scholar
Bernal, A., Olivar, M. P., Maynou, F. & de Puelles, M. L. F. Diet and feeding strategies of mesopelagic fishes in the western Mediterranean. Prog. Oceanogr. 135, 1–17 (2015).
Google Scholar
Gutiérrez-Rodríguez, A., Décima, M., Popp, B. N. & Landry, M. R. Isotopic invisibility of protozoan trophic steps in marine food webs. Limnol. Oceanogr. 59, 1590–1598 (2014).
Google Scholar
Hussey, N. E. et al. Rescaling the trophic structure of marine food webs. Ecol. Lett. 17, 239–250 (2014).
Google Scholar
Nielsen, J. M., Popp, B. N. & Winder, M. Meta-analysis of amino acid stable nitrogen isotope ratios for estimating trophic position in marine organisms. Oecologia 178, 631–642 (2015).
Google Scholar
Décima, M., Landry, M. R., Bradley, C. J. & Fogel, M. L. Alanine δ15N trophic fractionation in heterotrophic protists. Limnol. Oceanogr. 62, 2308–2322 (2017).
Google Scholar
Décima, M. & Landry, M. Resilience of plankton trophic structure to an eddy-stimulated diatom bloom in the North Pacific Subtropical Gyre. Mar. Ecol. Prog. Ser. 643, 33–48 (2020).
Google Scholar
Irigoien, X. et al. Large mesopelagic fish biomass and trophic efficiency in the Open Ocean. Nat. Commun. 5, 3271. https://doi.org/10.1038/ncomms4271 (2014).
Google Scholar
Cherel, Y., Fontaine, C., Richard, P. & Labat, J.-P. Isotopic niches and trophic levels of myctophid fishes and their predators in the Southern Ocean. Limnol. Oceanogr. 55, 324–332 (2010).
Google Scholar
Young, J. W. et al. Setting the stage for a global-scale trophic analysis of marine top predators: A multi-workshop review. Rev. Fish Biol. Fish. 25, 261–272 (2015).
Google Scholar
Klevjer, T. A. et al. Large scale patterns in vertical distribution and behaviour of mesopelagic scattering layers. Sci. Rep. 6, 19873. https://doi.org/10.1038/srep19873 (2016).
Google Scholar
Olivar, M. P. et al. Mesopelagic fishes across the tropical and equatorial Atlantic: Biogeographical and vertical patterns. Prog. Oceanogr. 151, 116–137 (2017).
Google Scholar
Eduardo, L. N. et al. Trophic ecology, habitat, and migratory behaviour of the viperfish Chauliodus sloani reveal a key mesopelagic player. Sci. Rep. 10, 20996. https://doi.org/10.1038/s41598-020-77222-8 (2020).
Google Scholar
Valls, M. et al. Trophic structure of mesopelagic fishes in the western Mediterranean based on stable isotopes of carbon and nitrogen. J. Mar. Syst. 138, 160–170 (2014).
Google Scholar
Choy, C. A., Popp, B. N., Hannides, C. C. S. & Drazen, J. C. Trophic structure and food resources of epipelagic and mesopelagic fishes in the North Pacific Subtropical Gyre ecosystem inferred from nitrogen isotopic compositions. Limnol. Oceanogr. 60, 1156–1171 (2015).
Google Scholar
Olivar, M. P., Bode, A., López-Pérez, C., Hulley, P. A. & Hernández-León, S. Trophic position of lanternfishes (Pisces: Myctophidae) of the tropical and equatorial Atlantic estimated using stable isotopes. ICES J. Mar. Sci. 76, 649–661 (2019).
Google Scholar
Richards, T. M., Sutton, T. T. & Wells, R. J. D. Trophic structure and sources of variation influencing the stable isotope signatures of meso- and bathypelagic micronekton fishes. Front. Mar. Sci. 7, 507992. https://doi.org/10.3389/fmars.2020.507992 (2020).
Google Scholar
Choy, C. A. et al. Global trophic position comparison of two dominant mesopelagic fish families (Myctophidae, Stomiidae) using amino acid nitrogen isotopic analyses. PLoS ONE 7, e50133. https://doi.org/10.1371/journal.pone.0050133 (2012).
Google Scholar
Wang, F. et al. Trophic interactions of mesopelagic fishes in the South China Sea illustrated by stable isotopes and fatty acids. Front. Mar. Sci. 5, 522. https://doi.org/10.3389/fmars.2018.00522 (2019).
Google Scholar
Czudaj, S. et al. Spatial variation in the trophic structure of micronekton assemblages from the eastern tropical North Atlantic in two regions of differing productivity and oxygen environments. Deep Sea Res. 163, 103275. https://doi.org/10.1016/j.dsr.2020.103275 (2020).
Google Scholar
FishBase. A Global Information System on Fishes (University of California, 2021).
Bligh, E. G. & Dyer, W. J. A rapid method of total lipid extraction and purification. Can. J. Biochem. Physiol. 37, 911–917 (1959).
Google Scholar
Coplen, T. B. Guidelines and recommended terms for expression of stable isotope-ratio and gas-ratio measurement results. Rapid Commun. Mass Spectrom. 25, 2538–2560 (2011).
Google Scholar
Chikaraishi, Y. et al. Determination of aquatic food-web structure based on compound-specific nitrogen isotopic composition of amino acids. Limnol. Oceanogr. Methods 7, 740–750 (2009).
Google Scholar
McCarthy, M. D., Lehman, J. & Kudela, R. Compound-specific amino acid δ15N patterns in marine algae: Tracer potential for cyanobacterial vs. eukaryotic organic nitrogen sources in the ocean. Geochim. Cosmochim. Acta 103, 104–120 (2013).
Google Scholar
Mompeán, C., Bode, A., Gier, E. & McCarthy, M. D. Bulk vs. aminoacid stable N isotope estimations of metabolic status and contributions of nitrogen fixation to size-fractionated zooplankton biomass in the subtropical N Atlantic. Deep Sea Res. 114, 137–148 (2016).
Google Scholar
McClelland, J. W. & Montoya, J. P. Trophic relationships and the nitrogen isotopic composition of amino acids in plankton. Ecology 83, 2173–2180 (2002).
Google Scholar
McMahon, K. W. & McCarthy, M. D. Embracing variability in amino acid d15N fractionation: Mechanisms, implications, and applications for trophic ecology. Ecosphere 7, e01511. https://doi.org/10.1002/ecs2.1511 (2016).
Google Scholar
Swanson, H. K. et al. A new probabilistic method for quantifying n-dimensional ecological niches and niche overlap. Ecology 96, 318–324 (2015).
Google Scholar
Bradley, C. J. et al. Trophic position estimates of marine teleosts using amino acid compound specific isotopic analysis. Limnol. Oceanogr. Methods 13, 476–493 (2015).
Google Scholar
Hammer, Ø., Harper, D. A. T. & Ryan, P. D. PAST: Paleontological statistics software package for education and data analysis. Palaeontol. Electron. 4, 1–9 (2001).
McCarthy, M. D., Benner, R., Lee, C. & Fogel, M. L. Amino acid nitrogen isotopic fractionation patterns as indicators of heterotrophy in plankton, particulate, and dissolved organic matter. Geochim. Cosmochim. Acta 71, 4727–4744 (2007).
Google Scholar
Hannides, C. C. S., Popp, B. N., Choy, C. A. & Drazen, J. C. Midwater zooplankton and suspended particle dynamics in the North Pacific Subtropical Gyre: A stable isotope perspective. Limnol. Oceanogr. 58, 1931–1946 (2013).
Google Scholar
Gloeckler, K. et al. Stable isotope analysis of micronekton around Hawaii reveals suspended particles are an important nutritional source in the lower mesopelagic and upper bathypelagic zones. Limnol. Oceanogr. 63, 1168–1180 (2018).
Google Scholar
Robison, B. H. Conservation of deep pelagic biodiversity. Conserv. Biol. 23, 847–858 (2009).
Google Scholar
Brun, P. et al. Climate change has altered zooplankton-fuelled carbon export in the North Atlantic. Nat. Ecol. Evol. 3, 416–423 (2019).
Google Scholar
Bode, M. et al. Feeding strategies of tropical and subtropical calanoid copepods throughout the eastern Atlantic Ocean: Latitudinal and bathymetric aspects. Prog. Oceanogr. 138, 268–282 (2015).
Google Scholar
Herndl, G. J. et al. Contribution of Archaea to total prokarytic production in the deep Atlantic Ocean. Appl. Environ. Microbiol. 71, 2303–2309 (2005).
Google Scholar
Varela, M. M., van Aken, H. M., Sintes, E., Reinthaler, T. & Herndl, G. J. Contribution of Crenarchaeota and bacteria to autotrophy in the North Atlantic interior. Environ. Microbiol. 13, 1524–1533 (2011).
Google Scholar
Clifford, E. L. et al. Taurine is a major carbon and energy source for marine prokaryotes in the North Atlantic Ocean off the Iberian Peninsula. Microb. Ecol. 78, 299–312 (2019).
Google Scholar
Hoen, D. K. et al. Amino acid 15N trophic enrichment factors of four large carnivorous fishes. J. Exp. Mar. Biol. Ecol. 453, 76–83 (2014).
Google Scholar
McMahon, K. W. & McCarthy, M. D. Embracing variability in amino acid δ15N fractionation: Mechanisms, implications, and applications for trophic ecology. Ecosphere 7, e01511. https://doi.org/10.1002/ecs2.1511 (2016).
Google Scholar
Pauly, D., Christensen, V. & Walters, C. Ecopath, ecosim, and ecospace as tools for evaluating ecosystem impact of fisheries. ICES J. Mar. Sci. 57, 697–706 (2000).
Google Scholar
Christensen, V. & Walters, C. Ecopath with ecosim: Methods, capabilities and limitations. Ecol. Model. 172, 109–139 (2004).
Google Scholar
McClain-Counts, J. P., Demopoulos, A. W. J. & Ross, S. W. Trophic structure of mesopelagic fishes in the Gulf of Mexico revealed by gut content and stable isotope analyses. Mar. Ecol. 38, e12449. https://doi.org/10.1111/maec.12449 (2017).
Google Scholar
Olivar, M. P. et al. The contribution of migratory mesopelagic fishes to neuston fish assemblages across the Atlantic, Indian and Pacific Oceans. Mar. Freshw. Res. 67, 1114–1127 (2016).
Google Scholar
Gartner, J. V. & Musick, J. A. Feeding habits of the deep-sea fish, Scopelogadus beanii (Pisces: Melamphaide), in the western North Atlantic. Deep Sea Res. A Oceanogr. Res. Pap. 36(10), 1457–1469. https://doi.org/10.1016/0198-0149(89)90051-4 (1989).
Google Scholar
Clarke, L. J., Trebilco, R., Walters, A., Polanowski, A. M. & Deagle, B. E. DNA-based diet analysis of mesopelagic fish from the southern Kerguelen axis. Deep-Sea Res. II Top. Stud. Oceanogr. https://doi.org/10.1016/j.dsr2.2018.09.001 (2020).
Google Scholar
Schmoker, C., Hernández-León, S. & Calbet, A. Microzooplankton grazing in the oceans: Impacts, data variability, knowledge gaps and future directions. J. Plankton Res. 35, 691–706 (2013).
Google Scholar
Calbet, A. & Saiz, E. The ciliate-copepod link in marine ecosystems. Aquat. Microb. Ecol. 38, 157–167 (2005).
Google Scholar
Zeldis, J. R. & Décima, M. Mesozooplankton connect the microbial food web to higher trophic levels and vertical export in the New Zealand subtropical convergence zone. Deep Sea Res. 155, 103146 (2020).
Google Scholar
Jennings, S., Pinnegar, J. K., Polunin, N. V. C. & Boon, T. W. Weak cross-species relationships between body size and trophic level belie powerful size-based trophic structuring in fish communities. J. Anim. Ecol. 70, 934–944 (2001).
Google Scholar
Bode, A., Carrera, P. & Lens, S. The pelagic foodweb in the upwelling ecosystem of Galicia (NW Spain) during spring: Natural abundance of stable carbon and nitrogen isotopes. ICES J. Mar. Sci. 60, 11–22 (2003).
Google Scholar
Hunt, B. P. V. et al. A coupled stable isotope-size spectrum approach to understanding pelagic food-web dynamics: A case study from the southwest sub-tropical Pacific. Deep Sea Res. 113, 208–224 (2015).
Google Scholar
Romero-Romero, S., Molina-Ramírez, A., Höfer, J. & Acuña, J. L. Body size-based trophic structure of a deep marine ecosystem. Ecology 97, 171–181 (2016).
Google Scholar
Barnes, C., Maxwell, D., Reuman, D. C. & Jennings, S. Global patterns in predator-prey size relationships reveal size dependency of trophic transfer efficiency. Ecology 91, 222–232 (2010).
Google Scholar
Schoener, T. W. Food webs from the small to the large. Ecology 70, 1559–1589 (1989).
Google Scholar
Zhou, M. What determines the slope of a plankton biomass spectrum?. J. Plankton Res. 28, 437–448 (2006).
Google Scholar
Van der Zanden, M. J. & Fetzer, W. Global patterns of aquatic food chain length. Oikos 116, 1378–1388 (2007).
Google Scholar
Basedow, S. L., de Silva, N. A. L., Bode, A. & van Beusekorn, J. Trophic positions of mesozooplankton across the North Atlantic: estimates derived from biovolume spectrum theories and stable isotope analyses. J. Plankton Res. 38, 1364–1378 (2016).
Google Scholar
Williams, R. J. & Martinez, N. D. Limits to trophic levels and omnivory in complex food webs: Theory and data. Am. Nat. 163, 458–468 (2004).
Google Scholar
Nagata, T. et al. Emerging concepts on microbial processes in the bathypelagic ocean – ecology, biogeochemistry, and genomics. Deep Sea Res. II 57, 1519–1536 (2010).
Google Scholar
Source: Ecology - nature.com