in

Salp blooms drive strong increases in passive carbon export in the Southern Ocean

[adace-ad id="91168"]
  • Roemmich, D. et al. Unabated planetary warming and its ocean structure since 2006. Nat. Clim. Change 5, 240–245 (2015).

    Article 
    ADS 

    Google Scholar 

  • Frölicher, T. L. et al. Dominance of the Southern Ocean in anthropogenic carbon and heat uptake in CMIP5 models. J. Clim. 28, 862–886 (2015).

    Article 
    ADS 

    Google Scholar 

  • Buesseler, K. O. & Boyd, P. W. Shedding light on processes that control particle export and flux attenuation in the twilight zone of the open ocean. Limnol. Oceanogr. 54, 1210–1232 (2009).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Arteaga, L., Haentjens, N., Boss, E., Johnson, K. S. & Sarmiento, J. L. Assessment of export efficiency equations in the Southern Ocean applied to satellite-based net primary production. J. Geophys. Res.-Oceans 123, 2945–2964 (2018).

    Article 
    ADS 

    Google Scholar 

  • Siegel, D. A. et al. Prediction of the export and fate of global ocean net primary production: the EXPORTS science plan. Front. Marine Sc. 3, 22 (2016).

  • Perissinotto, R. & Pakhomov, E. A. The trophic role of the tunicate Salpa thompsoni in the Antarctic marine ecosystem. J. Mar. Syst. 17, 361–374 (1998).

    Article 

    Google Scholar 

  • Atkinson, A., Siegel, V., Pakhomov, E. & Rothery, P. Long-term decline in krill stock and increase in salps within the Southern Ocean. Nature 432, 100–103 (2004).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Perissinotto, R. & Pakhomov, E. A. Contribution of salps to carbon flux of marginal ice zone of the Lazarev sea, southern ocean. Mar. Biol. 131, 25–32 (1998).

    Article 
    CAS 

    Google Scholar 

  • Phillips, B., Kremer, P. & Madin, L. P. Defecation by Salpa thompsoni and its contribution to vertical flux in the Southern Ocean. Mar. Biol. 156, 455–467 (2009).

    Article 

    Google Scholar 

  • Stone, J. P. & Steinberg, D. K. Salp contributions to vertical carbon flux in the Sargasso Sea. Deep-Sea Res. Part I 113, 90–100 (2016).

    Article 
    CAS 

    Google Scholar 

  • Ramaswamya, V., Sarin, M. M. & Rengarajan, R. Enhanced export of carbon by salps during the northeast monsoon period in the northern Arabian Sea. Deep-Sea Res. Part II 52, 1922–1929 (2005).

    Article 
    ADS 

    Google Scholar 

  • Smith, K. L. et al. Large salp bloom export from the upper ocean and benthic community response in the abyssal northeast Pacific: day to week resolution. Limnol. Oceanogr. 59, 745–757 (2014).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Madin, L. P. & Kremer, P. Determination of the filter feeding rates of salps (Tunicata, Thaliacea). ICES J. Mar. Sci. 52, 583–595 (1995).

    Article 

    Google Scholar 

  • Wiebe, P. H., Madin, L. P., Haury, L. R., Harbison, G. R. & Philbin, L. M. Diel vertical migration by Salpa aspera and its potential for large-scale particulate organic matter transport to the deep-sea. Mar. Biol. 53, 249–255 (1979).

    Article 

    Google Scholar 

  • Dadon-Pilosof, A., Lombard, F., Genin, A., Sutherland, K. R. & Yahel, G. Prey taxonomy rather than size determines salp diets. Limnol. Oceanogr. 64, 1996–2010 (2019).

    Article 
    ADS 

    Google Scholar 

  • Stukel, M. R., Décima, M., Selph, K. E. & Gutiérrez-Rodríguez, A. Size-specific grazing and competitive interactions between large salps and protistan grazers. Limnol. Oceanogr. 66, 2521–2534 (2021).

  • Madin, L. P. Production, composition and sedimentation of salp fecal pellets in oceanic waters. Mar. Biol. 67, 39–45 (1982).

    Article 

    Google Scholar 

  • Michaels, A. F. & Silver, M. W. Primary production, sinking fluxes and the microbial food web. Deep-Sea Res. Part I 35, 473–490 (1988).

    Article 
    ADS 

    Google Scholar 

  • Luo, J. Y. et al. Gelatinous zooplankton‐mediated carbon flows in the global oceans: a data‐driven modeling study. Glob. Biogeochem. Cycle 34, e2020GB006704 (2020).

  • Kremer, P. & Madin, L. P. Particle retention efficiency of salps. J. Plankton Res. 14, 1009–1015 (1992).

    Article 

    Google Scholar 

  • Harbison, G. R. & Gilmer, R. W. Feeding rates of pelagic tunicate Pegea confederata and 2 other salps. Limnol. Oceanogr. 21, 517–528 (1976).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Harbison, G. R. & McAlister, V. L. The filter-feeding rates and particle retention efficiencies of 3 species of Cyclosalpa (Tunicata, Thaliacea). Limnol. Oceanogr. 24, 875–892 (1979).

    Article 
    ADS 

    Google Scholar 

  • Mullin, M. M. In situ measurement of filtering rates of the salp Thalia democratica, on phytoplankton and bacteria. J. Plankton Res. 5, 279–288 (1983).

    Article 

    Google Scholar 

  • Deibel, D. Clearance rates of the salp Thalia democratica fed naturally occurring particles. Mar. Biol. 86, 47–54 (1985).

    Article 

    Google Scholar 

  • Fender, C. K. et al. Prey size spectra and predator:prey ratios of 7 species of New Zealand salps. Mar. Biol. (in press).

  • Chiswell, S. M., Bostock, H. C., Sutton, P. J. H. & Williams, M. J. M. Physical oceanography of the deep seas around New Zealand: a review. N.Z. J. Mar. Freshw. Res. 49, 286–317 (2015).

    Article 

    Google Scholar 

  • Henschke, N. et al. Salp-falls in the Tasman Sea: a major food input to deep-sea benthos. Mar. Ecol. Prog. Ser. 491, 165–175 (2013).

    Article 
    ADS 

    Google Scholar 

  • Childerhouse, S., Dix, B. & Gales, N. Diet of new Zealand sea lions (Phocarctos hookeri) at the Auckland islands. Wildl. Res. 28, 291–298 (2001).

    Article 

    Google Scholar 

  • Horn, P. L., Burrell, T., Connell, A. & Dunn, M. R. A comparison of the diets of silver (Seriolella punctata) and white (Seriolella caerulea) warehou. Mar. Biol. Res. 7, 576–591 (2011).

    Article 

    Google Scholar 

  • Horn, P. L., Forman, J. S. & Dunn, M. R. Dietary partitioning by two sympatric fish species, red cod (Pseudophycis bachus) and sea perch (Helicolenus percoides), on Chatham Rise, New Zealand. Mar. Biol. Res. 8, 624–634 (2012).

    Article 

    Google Scholar 

  • Forman, J. S., Horn, P. L. & Stevens, D. W. Diets of deepwater Oreos (Oreosomatidae) and orange roughy Hoplostethus atlanticus. J. Fish. Biol. 88, 2275–2302 (2016).

    Article 
    CAS 

    Google Scholar 

  • Carroll, E. L. et al. Multi-locus DNA metabarcoding of zooplankton communities and scat reveal trophic interactions of a generalist predator. Sci. Rep. 9, 1–14 (2019).

  • Savoye, N. et al. 234Th sorption and export models in the water column: a review. Mar. Chem. 100, 234–249 (2006).

    Article 
    CAS 

    Google Scholar 

  • Sutton, P. J. H. The Southland Current: a subantarctic current. N.Z. J. Mar. Freshw. Res. 37, 645–652 (2003).

    Article 

    Google Scholar 

  • Foxton, P. The distribution and life history of Salpa thompsoni Foxton with observations on a related species, Salpa gerlachei Foxton. Discovery Rep. 34, 1–116 (1966).

  • Loeb, V. J. & Santora, J. A. Population dynamics of Salpa thompsoni near the Antarctic Peninsula: growth rates and interannual variations in reproductive activity (1993–2009). Prog. Oceanogr. 96, 93–107 (2012).

    Article 
    ADS 

    Google Scholar 

  • Pakhomov, E. A. & Hunt, B. P. V. Trans-Atlantic variability in ecology of the pelagic tunicate Salpa thompsoni near the Antarctic Polar Front. Deep-Sea Res. Part II 138, 126–140 (2017).

    Article 

    Google Scholar 

  • Lüskow, F., Pakhomov, E. A., Stukel, M. R. & Décima, M. Biology of Salpa thompsoni at the Chatham Rise, New Zealand: demography, growth, and diel vertical migration. Mar. Biol. 167, 1–18 (2020).

  • Pakhomov, E. A. & Froneman, P. W. Zooplankton dynamics in the eastern Atlantic sector of the Southern Ocean during the austral summer 1997/1998—Part 2: grazing impact. Deep-Sea Res. Part II 51, 2617–2631 (2004).

    Article 
    ADS 

    Google Scholar 

  • Iversen, M. H. et al. Sinkers or floaters? Contribution from salp pellets to the export flux during a large bloom event in the Southern. Ocean. Deep-Sea Res. Part II 138, 116–125 (2017).

    Article 
    CAS 

    Google Scholar 

  • Buesseler, K. O., Boyd, P. W., Black, E. E. & Siegel, D. A. Metrics that matter for assessing the ocean biological carbon pump. Proc. Natl Acad. Sci. USA 117, 9679 (2020).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Love, M. I., Huber, W. & Anders, S. Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome Biol. 15, 550 (2014).

    Article 

    Google Scholar 

  • Hall, J., Safi, K. & Cumming, A. Role of microzooplankton grazers in the subtropical and subantarctic waters to the east of New Zealand. N.Z. J. Mar. Freshw. Res. 38, 91–101 (2004).

    Article 

    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. Part I 155, 103146 (2020).

    Article 
    CAS 

    Google Scholar 

  • Hall, J. A., James, M. R. & Bradford-Grieve, J. M. Structure and dynamics of the pelagic microbial food web of the Subtropical Convergence region east of New Zealand. Aquat. Micro. Ecol. 20, 95–105 (1999).

    Article 

    Google Scholar 

  • Bradford-Grieve, J. M. et al. Pelagic ecosystem structure and functioning in the subtropical front region east of New Zealand in austral winter and spring 1993. J. Plankton Res. 21, 405–428 (1999).

    Article 

    Google Scholar 

  • Nodder, S. & Gall, M. Pigment fluxes from the Subtropical Convergence region, east of New Zealand: relationships to planktonic community structure. N.Z. J. Mar. Freshw. Res. 32, 441–465 (1998).

    Article 
    CAS 

    Google Scholar 

  • Nodder, S. D., Chiswell, S. M. & Northcote, L. C. Annual cycles of deep-ocean biogeochemical export fluxes in subtropical and subantarctic waters, southwest Pacific Ocean. J. Geophys. Res.: Oceans 121, 2405–2424 (2016).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Kiko, R. et al. Biological and physical influences on marine snowfall at the equator. Nat. Geosci. 10, 852-+ (2017).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Kelly, R. P., Shelton, A. O. & Gallego, R. Understanding PCR processes to draw meaningful conclusions from environmental DNA studies. Sci. Rep. 9, 12133 (2019).

    Article 
    ADS 

    Google Scholar 

  • Caron, D. A., Madin, L. P. & Cole, J. J. Composition and degradation of salp fecal pellets: implications for vertical flux in oceanic environments. J. Mar. Res. 47, 829–850 (1989).

    Article 
    CAS 

    Google Scholar 

  • Sempere, R., Yoro, S., Wambeke, F. V. & Charriere, B. Microbial decomposition of large organic particles in the northwestern Mediterranean Sea: an experimental approach. Mar. Ecol. Prog. Ser. 198, 61–72 (2000).

    Article 
    ADS 

    Google Scholar 

  • Dell’Anno, A. & Corinaldesi, C. Degradation and turnover of extracellular DNA in marine sediments: ecological and methodological considerations. Appl. Environ. Microbiol. 70, 4384–4386 (2004).

    Article 
    ADS 

    Google Scholar 

  • Torti, A., Lever, M. A. & Jørgensen, B. B. Origin, dynamics, and implications of extracellular DNA pools in marine sediments. Mar. Genomics 24, 185–196 (2015).

    Article 

    Google Scholar 

  • Norris, R. Sediments of the Chatham Rise. N.Z. Dep. Sci. Ind. Res. Res. Bull. 159, 38 (1964).

    Google Scholar 

  • Waite, A. M., Safi, K. A., Hall, J. A. & Nodder, S. D. Mass sedimentation of picoplankton embedded in organic aggregates. Limnol. Oceanogr. 45, 87–97 (2000).

    Article 
    ADS 

    Google Scholar 

  • Gafar, N. A. & Schulz, K. G. A three-dimensional niche comparison of Emiliania huxleyi and Gephyrocapsa oceanica: reconciling observations with projections. Biogeosciences 15, 3541–3560 (2018).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Eynaud, F., Giraudeau, J., Pichon, J. J. & Pudsey, C. J. Sea-surface distribution of coccolithophores, diatoms, silicoflagellates and dinoflagellates in the South Atlantic Ocean during the late austral summer 1995. Deep-Sea Res. Part I 46, 451–482 (1999).

    Article 

    Google Scholar 

  • Hagino, K., Okada, H. & Matsuoka, H. Coccolithophore assemblages and morphotypes of Emiliania huxleyi in the boundary zone between the cold Oyashio and warm Kuroshio currents off the coast of Japan. Mar. Micropaleontol. 55, 19–47 (2005).

    Article 
    ADS 

    Google Scholar 

  • Rhodes, L. L., Peake, B. M., Mackenzie, A. L. & Marwick, S. Coccolithophores Gephyrocapsa oceanica and Emiliana Huxleyi (Prymnesiophyceae = Haptophyceae) in New Zealand’s coastal waters: characteristics of blooms and growth in laboratory culture. N.Z. J. Mar. Freshw. Res. 29, 345–357 (1995).

    Article 

    Google Scholar 

  • Ziveri, P., de Bernardi, B., Baumann, K.-H., Stoll, H. M. & Mortyn, P. G. Sinking of coccolith carbonate and potential contribution to organic carbon ballasting in the deep ocean. Deep-Sea Res. Part II 54, 659–675 (2007).

    Article 
    ADS 

    Google Scholar 

  • Buesseler, K. O. et al. VERTIGO (VERtical Transport In the Global Ocean): a study of particle sources and flux attenuation in the North Pacific. Deep Sea Res. II 55, 1522–1539 (2008).

    Article 
    ADS 

    Google Scholar 

  • Billett, D. S. M., Lampitt, R. S., Rice, A. L. & Mantoura, R. F. C. Seasonal sedimentation of phytoplankton to the deep-sea benthos. Nature 302, 520–522 (1983).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Martin, J. H., Fitzwater, S. E., Gordon, R. M., Hunter, C. N. & Tanner, S. J. Iron, primary production and carbon nitrogen fluxes during the JGOFS North Atlantic Bloom Experiment. Deep-Sea Res. Part II 40, 115–134 (1993).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Buesseler, K. O. et al. The effect of marginal ice-edge dynamics on production and export in the Southern Ocean along 170 degrees W. Deep-Sea Res. Part II 50, 579–603 (2003).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Kiko, R. et al. Zooplankton-mediated fluxes in the eastern tropical north. Atl. Front. Mar. Sci. 7, 21 (2020).

    Google Scholar 

  • Kelly, T. B. et al. The importance of mesozooplankton diel vertical migration for sustaining a mesopelagic food web. Front. Mar. Sci. 6, 508 (2019).

  • Maiti, K., Charette, M. A., Buesseler, K. O. & Kahru, M. An inverse relationship between production and export efficiency in the Southern Ocean. Geophys. Res. Lett. 40, 1557–1561 (2013).

    Article 
    ADS 

    Google Scholar 

  • Loeb, V. et al. Effects of sea-ice extent and krill or salp dominance on the Antarctic food web. Nature 387, 897–900 (1997).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Steinberg, D. K. et al. Long-term (1993–2013) changes in macrozooplankton off the Western Antarctic Peninsula. Deep-Sea Res. Part I 101, 54–70 (2015).

    Article 

    Google Scholar 

  • Cabanes, D. J. E. et al. First evaluation of the role of salp fecal pellets on iron biogeochemistry. Front. Mar. Sci. 3, 10 (2017).

    Article 

    Google Scholar 

  • Belcher, A. et al. Krill faecal pellets drive hidden pulses of particulate organic carbon in the marginal ice zone. Nat. Commun. 10, 1–8 (2019).

  • Manno, C. et al. Continuous moulting by Antarctic krill drives major pulses of carbon export in the north Scotia Sea, Southern Ocean. Nat. Commun. 11, 6051 (2020).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Law, C. S. et al. Did dilution limit the phytoplankton response to iron addition in HNLCLSi sub-Antarctic waters during the SAGE experiment? Deep-Sea Res. Part II 58, 786–799 (2011).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Gutiérrez‐Rodríguez, A. et al. Decoupling between phytoplankton growth and microzooplankton grazing enhances productivity in Subantarctic waters on Campbell Plateau, southeast of New Zealand. J. Geophys. Res.: Oceans 125, e2019JC015550 (2020).

  • Sherman, J., Gorbunov, M. Y., Schofield, O. & Falkowski, P. G. Photosynthetic energy conversion efficiency in the West Antarctic Peninsula. Limnol. Oceanogr. 65, 1–14 (2020).

  • Peterson, B. J. Aquatic primary productivity and the 14C-CO2 method: a history of the productivity problem. Annu Rev. Ecol. Syst. 11, 359–385 (1980).

    Article 

    Google Scholar 

  • Landry, M. R. & Hassett, R. P. Estimating the grazing impact of marine microzooplankton. Mar. Biol. 67, 283–288 (1982).

    Article 

    Google Scholar 

  • Landry, M. R., Haas, L. W. & Fagerness, V. L. Dynamics of microbial plankton communities—experiments in Kaneohe Bay, Hawaii. Mar. Ecol. Prog. Ser. 16, 127–133 (1984).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Gutierrez-Rodriguez, A., Latasa, M., Estrada, M., Vidal, M. & Marrase, C. Carbon fluxes through major phytoplankton groups during the spring bloom and post-bloom in the Northwestern Mediterranean Sea. Deep Sea Res. Part I 57, 486–500 (2010).

    Article 
    CAS 

    Google Scholar 

  • Gutierrez-Rodriguez, A. & Latasa, M. Pigment-based measurements of phytoplankton rates. in Phytoplankton Pigments Characterization, Chemotaxonomy and Applications in Oceanography (eds Roy, S. et al.) (Cambridge University Press, 2011) 472–495.

  • Lorenzen, C. J. Determination of chlorophyll and pheo-pigments: spectrophotometric equations. Limnol. Oceanogr. 12, 343–346 (1967).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Conover, R. J., Durvasula, R., Roy, S. & Wang, R. Probable loss of chlorophyll-derived pigments during passage through the gut of zooplankton, and some of the consequences. Limnol. Oceanogr. 31, 878–887 (1986).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Latasa, M. A simple method to increase sensitivity for RP-HPLC phytoplankton pigment analysis. Limnol. Oceanogr. Meth 12, 46–53 (2014).

    Article 

    Google Scholar 

  • Caporaso, J. G., Paszkiewicz, K., Field, D., Knight, R. & Gilbert, J. A. The Western English Channel contains a persistent microbial seed bank. ISME J. 6, 1089–1093 (2012).

    Article 
    CAS 

    Google Scholar 

  • Callahan, B. J. et al. DADA2: high-resolution sample inference from Illumina amplicon data. Nat. Methods 13, 581-+ (2016).

    Article 
    CAS 

    Google Scholar 

  • Quast, C. et al. The SILVA ribosomal RNA gene database project: improved data processing and web-based tools. Nucleic Acids Res. 41, D590–D596 (2013).

    Article 
    CAS 

    Google Scholar 

  • McMurdie, P. J. & Holmes, S. phyloseq: an R package for reproducible interactive analysis and graphics of microbiome census data. PLoS ONE 8, e61217 (2013).

  • Oksanen, J. et al. vegan: community ecology package. R package version 2.5-6. (2019).

  • Piredda, R. et al. Diversity and temporal patterns of planktonic protist assemblages at a Mediterranean Long Term Ecological Research site. FEMS Microbiol. Ecol. 93, fiw200 (2017).

  • Guillou, L. et al. The Protist Ribosomal Reference database (PR2): a catalog of unicellular eukaryote Small Sub-Unit rRNA sequences with curated taxonomy. Nucleic Acids Res. 41, D597–D604 (2013).

    Article 
    CAS 

    Google Scholar 

  • Pike, S. M., Buesseler, K. O., Andrews, J. & Savoye, N. Quantification of Th-234 recovery in small volume sea water samples by inductively coupled plasma-mass spectrometry. J. Radioanal. Nucl. Chem. 263, 355–360 (2005).

    Article 
    CAS 

    Google Scholar 

  • Benitez-Nelson, C. R. et al. Testing a new small-volume technique for determining Th-234 in seawater. J. Radioanal. Nucl. Chem. 248, 795–799 (2001).

    Article 
    CAS 

    Google Scholar 

  • Bone, Q. The Biology of Pelagic Tunicates (Oxford University Press, 1998).

  • Foxton, P. An aid to the detailed examination of salps [Tunicata: Salpidae]. J. Mar. Biol. Assoc. UK 45, 679–681 (1965).

    Article 

    Google Scholar 

  • Thompson, H. Pelagic Tunicates of Australia (Commonwealth Council for Scientific and Industrial Research, 1948).

  • Iguchi, N. & Ikeda, T. Metabolism and elemental composition of aggregate and solitary forms of Salpa thompsoni (Tunicata: Thaliacea) in waters off the Antarctic Peninsula during austral summer 1999. J. Plankton Res. 26, 1025–1037 (2004).

    Article 
    CAS 

    Google Scholar 

  • von Harbou, L. et al. Salps in the Lazarev Sea, Southern Ocean: I. feeding dynamics. Mar. Biol. 158, 2009–2026 (2011).

    Article 

    Google Scholar 

  • Pakhomov, E. A., Dubischar, C. D., Strass, V., Brichta, M. & Bathmann, U. V. The tunicate Salpa thompsoni ecology in the Southern Ocean. I. Distribution, biomass, demography and feeding ecophysiology. Mar. Biol. 149, 609–623 (2006).

    Article 

    Google Scholar 

  • Huntley, M. E., Sykes, P. F. & Marin, V. Biometry and trophodynamics of Salp thompsoni Foxton (Tunicata, Thaliacea) near the Antarctic peninsula in austral summer 1983–1984. Polar Biol. 10, 59–70 (1989).

    Article 

    Google Scholar 

  • Knauer, G. A., Martin, J. H. & Bruland, K. W. Fluxes of particulate carbon, nitrogen, and phosphorus in the upper water column of the northeast Pacific. Deep Sea Res. Part I 26, 97–108 (1979).

    Article 
    ADS 
    CAS 

    Google Scholar 

  • Karl, D. M. et al. Seasonal and interannual variability in primary production and particle flux at Station ALOHA. Deep-Sea Res. Part II 43, 539–568 (1996).

    Article 
    ADS 
    CAS 

    Google Scholar 


  • Source: Ecology - nature.com

    MIT Solve announces 2023 global challenges and Indigenous Communities Fellowship

    Genomics discovery of giant fungal viruses from subsurface oceanic crustal fluids