Articles | Volume 15, issue 16
Research article 16 Aug 2018
Research article | 16 Aug 2018
Deep-sea benthic communities and oxygen fluxes in the Arctic Fram Strait controlled by sea-ice cover and water depth
Ralf Hoffmann et al.
No articles found.
Emil De Borger, Justin Tiano, Ulrike Braeckman, Adriaan D. Rijnsdorp, and Karline Soetaert
Biogeosciences, 18, 2539–2557,Short summary
Bottom trawling alters benthic mineralization: the recycling of organic material (OM) to free nutrients. To better understand how this occurs, trawling events were added to a model of seafloor OM recycling. Results show that bottom trawling reduces OM and free nutrients in sediments through direct removal thereof and of fauna which transport OM to deeper sediment layers protected from fishing. Our results support temporospatial trawl restrictions to allow key sediment functions to recover.
Massimiliano Molari, Felix Janssen, Tobias R. Vonnahme, Frank Wenzhöfer, and Antje Boetius
Biogeosciences, 17, 3203–3222,Short summary
Industrial-scale mining of deep-sea polymetallic nodules will remove nodules in large areas of the sea floor. We describe community composition of microbes associated with nodules of the Peru Basin. Our results show that nodules provide a unique ecological niche, playing an important role in shaping the diversity of the benthic deep-sea microbiome and potentially in element fluxes. We believe that our findings are highly relevant to expanding our knowledge of the impact associated with mining.
Emil De Borger, Justin Tiano, Ulrike Braeckman, Tom Ysebaert, and Karline Soetaert
Biogeosciences, 17, 1701–1715,Short summary
By applying a novel technique to quantify organism-induced sediment–water column fluid exchange (bioirrigation), we show that organisms in subtidal (permanently submerged) areas have similar bioirrigation rates as those that inhabit intertidal areas (not permanently submerged), but organisms in the latter irrigate deeper burrows in this study. Our results expand on traditional methods to quantify bioirrigation rates and broaden the pool of field measurements of bioirrigation rates.
Ulrike Braeckman, Felix Janssen, Gaute Lavik, Marcus Elvert, Hannah Marchant, Caroline Buckner, Christina Bienhold, and Frank Wenzhöfer
Biogeosciences, 15, 6537–6557,Short summary
Global warming has altered Arctic phytoplankton communities, with unknown effects on deep-sea communities that depend strongly on food produced at the surface. We compared the responses of Arctic deep-sea benthos to input of phytodetritus from diatoms and coccolithophorids. Coccolithophorid carbon was 5× less recycled than diatom carbon. The utilization of the coccolithophorid carbon may be less efficient, so a shift from diatom to coccolithophorid blooms could entail a delay in carbon cycling.
Sebastiaan Mestdagh, Leila Bagaço, Ulrike Braeckman, Tom Ysebaert, Bart De Smet, Tom Moens, and Carl Van Colen
Biogeosciences, 15, 2587–2599,Short summary
We studied how invertebrate communities of mudflats are affected by sudden deposition of sediment. We applied sediment layers of different thickness to mudflat communities and studied how their densities, diversity, and behaviour and the exchange of oxygen between the bottom and the water column changed. We found that some species easily diminish in numbers, while others become more active after deposition. The interaction of all species effects influences the environment, i.e. oxygen exchange.
H. Brenner, U. Braeckman, M. Le Guitton, and F. J. R. Meysman
Biogeosciences, 13, 841–863,Short summary
Alkalinity released from sediments of the southern North Sea can play an important role in the carbon cycle of the North Sea by lowering the pCO2 of the seawater and thus increasing the CO2 flux between the atmosphere and the water. However, not every single mole alkalinity generated in sediments leads to an additional CO2 uptake, as certain reactions in the water column can negate the respective alkalinity release.
J. Felden, A. Lichtschlag, F. Wenzhöfer, D. de Beer, T. Feseker, P. Pop Ristova, G. de Lange, and A. Boetius
Biogeosciences, 10, 3269–3283,
Related subject area
Biogeochemistry: Open OceanOn the barium–oxygen consumption relationship in the Mediterranean Sea: implications for mesopelagic marine snow remineralizationCompound high-temperature and low-chlorophyll extremes in the ocean over the satellite periodCan machine learning extract the mechanisms controlling phytoplankton growth from large-scale observations? – A proof-of-concept studyReviews and syntheses: The biogeochemical cycle of silicon in the modern oceanOxygen budget of the north-western Mediterranean deep- convection regionCross-basin differences in the nutrient assimilation characteristics of induced phytoplankton blooms in the subtropical Pacific watersDynamics of the deep chlorophyll maximum in the Black Sea as depicted by BGC-Argo floatsNitrate assimilation and regeneration in the Barents Sea: insights from nitrate isotopesAssimilating synthetic Biogeochemical-Argo and ocean colour observations into a global ocean model to inform observing system designSouthern Ocean Biogeochemical Argo detect under-ice phytoplankton growth before sea ice retreatA new intermittent regime of convective ventilation threatens the Black Sea oxygenation statusReviews and syntheses: Present, past, and future of the oxygen minimum zone in the northern Indian OceanParticulate rare earth element behavior in the North Atlantic (GEOVIDE cruise)Elevated sources of cobalt in the Arctic OceanCarbon Export and Fate Beneath a Dynamic Upwelled Filament off the California CoastIncrease in ocean acidity variability and extremes under increasing atmospheric CO2Impact of dust enrichment on Mediterranean plankton communities under present and future conditions of pH and temperature: an experimental overviewCan ocean community production and respiration be determined by measuring high-frequency oxygen profiles from autonomous floats?Assessing the value of biogeochemical Argo profiles versus ocean color observations for biogeochemical model optimization in the Gulf of MexicoThe Southern Annular Mode (SAM) influences phytoplankton communities in the seasonal ice zone of the Southern OceanContrasted release of insoluble elements (Fe, Al, REE, Th, Pa) after dust deposition in seawater: a tank experiment approachProfiling float observation of thermohaline staircases in the western Mediterranean Sea and impact on nutrient fluxesOcean carbonate system variability in the North Atlantic Subpolar surface water (1993–2017)Characterizing the surface microlayer in the Mediterranean Sea: trace metal concentrations and microbial plankton abundanceSpatial variations in silicate-to-nitrate ratios in Southern Ocean surface waters are controlled in the short term by physics rather than biologyPhytoplankton and dimethylsulfide dynamics at two contrasting Arctic ice edgesExperiment design and bacterial abundance control extracellular H2O2 concentrations during four series of mesocosm experimentsSeasonal cycling of zinc and cobalt in the Southeast Atlantic along the GEOTRACES GA10 sectionDissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)No nitrogen fixation in the Bay of Bengal?Trends and decadal oscillations of oxygen and nutrients at 50 to 300 m depth in the equatorial and North PacificPhysical drivers of the nitrate seasonal variability in the Atlantic cold tongueCoccolithophore biodiversity controls carbonate export in the Southern OceanArctic (Svalbard islands) active and exported diatom stocks and cell health statusHow will the key marine calcifier Emiliania huxleyi respond to a warmer and more thermally variable ocean?Ideas and perspectives: Is dark carbon fixation relevant for oceanic primary production estimates?Sensitivity of ocean biogeochemistry to the iron supply from the Antarctic Ice Sheet explored with a biogeochemical modelIsotopic fractionation of carbon during uptake by phytoplankton across the South Atlantic subtropical convergenceThe effect of marine aggregate parameterisations on nutrients and oxygen minimum zones in a global biogeochemical modelSensitivity of atmospheric CO2 to regional variability in particulate organic matter remineralization depthsNutrient distribution and nitrogen and oxygen isotopic composition of nitrate in water masses of the subtropical southern Indian OceanWhat drives the latitudinal gradient in open-ocean surface dissolved inorganic carbon concentration?Investigating the effect of El Niño on nitrous oxide distribution in the eastern tropical South PacificReciprocal bias compensation and ensuing uncertainties in model-based climate projections: pelagic biogeochemistry versus ocean mixingInputs and processes affecting the distribution of particulate iron in the North Atlantic along the GEOVIDE (GEOTRACES GA01) sectionAtmospheric deposition fluxes over the Atlantic Ocean: a GEOTRACES case studyPhytoplankton calcifiers control nitrate cycling and the pace of transition in warming icehouse and cooling greenhouse climatesEvidence of high N2 fixation rates in the temperate northeast AtlanticThe oceanic cycle of carbon monoxide and its emissions to the atmosphereThe export flux of particulate organic carbon derived from 210Po∕210Pb disequilibria along the North Atlantic GEOTRACES GA01 transect: GEOVIDE cruise
Stéphanie H. M. Jacquet, Dominique Lefèvre, Christian Tamburini, Marc Garel, Frédéric A. C. Le Moigne, Nagib Bhairy, and Sophie Guasco
Biogeosciences, 18, 2205–2212,Short summary
We present new data concerning the relation between biogenic barium (Baxs, a tracer of carbon remineralization at mesopelagic depths), O2 consumption and prokaryotic heterotrophic production (PHP) in the Mediterranean Sea. The purpose of this paper is to improve our understanding of the relation between Baxs, PHP and O2 and to test the validity of the Dehairs transfer function in the Mediterranean Sea. This relation has never been tested in the Mediterranean Sea.
Natacha Le Grix, Jakob Zscheischler, Charlotte Laufkötter, Cecile S. Rousseaux, and Thomas L. Frölicher
Biogeosciences, 18, 2119–2137,Short summary
Marine ecosystems could suffer severe damage from the co-occurrence of a marine heat wave with extremely low chlorophyll concentration. Here, we provide a first assessment of compound marine heat wave and low-chlorophyll events in the global ocean from 1998 to 2018. We reveal hotspots of these compound events in the equatorial Pacific and in the Arabian Sea and show that they mostly occur in summer at high latitudes and their frequency is modulated by large-scale modes of climate variability.
Christopher Holder and Anand Gnanadesikan
Biogeosciences, 18, 1941–1970,Short summary
A challenge for marine ecologists in studying phytoplankton is linking small-scale relationships found in a lab to broader relationships observed on large scales in the environment. We investigated whether machine learning (ML) could help connect these small- and large-scale relationships. ML was able to provide qualitative information about the small-scale processes from large-scale information. This method could help identify important relationships from observations in future research.
Paul J. Tréguer, Jill N. Sutton, Mark Brzezinski, Matthew A. Charette, Timothy Devries, Stephanie Dutkiewicz, Claudia Ehlert, Jon Hawkings, Aude Leynaert, Su Mei Liu, Natalia Llopis Monferrer, María López-Acosta, Manuel Maldonado, Shaily Rahman, Lihua Ran, and Olivier Rouxel
Biogeosciences, 18, 1269–1289,Short summary
Silicon is the second most abundant element of the Earth's crust. In this review, we show that silicon inputs and outputs, to and from the world ocean, are 57 % and 37 % higher, respectively, than previous estimates. These changes are significant, modifying factors such as the geochemical residence time of silicon, which is now about 8000 years and 2 times faster than previously assumed. We also update the total biogenic silica pelagic production and provide an estimate for sponge production.
Caroline Ulses, Claude Estournel, Marine Fourrier, Laurent Coppola, Fayçal Kessouri, Dominique Lefèvre, and Patrick Marsaleix
Biogeosciences, 18, 937–960,Short summary
We analyse the seasonal cycle of O2 and estimate an annual O2 budget in the north-western Mediterranean deep-convection region, using a numerical model. We show that this region acts as a large sink of atmospheric O2 and as a major source of O2 for the western Mediterranean Sea. The decrease in the deep convection intensity predicted in recent projections may have important consequences on the overall uptake of O2 in the Mediterranean Sea and on the O2 exchanges with the Atlantic Ocean.
Fuminori Hashihama, Hiroaki Saito, Taketoshi Kodama, Saori Yasui-Tamura, Jota Kanda, Iwao Tanita, Hiroshi Ogawa, E. Malcolm S. Woodward, Philip W. Boyd, and Ken Furuya
Biogeosciences, 18, 897–915,Short summary
We investigated the nutrient assimilation characteristics of deep-water-induced phytoplankton blooms across the subtropical North and South Pacific Ocean. Nutrient drawdown ratios of dissolved inorganic nitrogen to phosphate were anomalously low in the western North Pacific, likely due to the high phosphate uptake capability of low-phosphate-adapted phytoplankton. The anomalous phosphate uptake might influence the maintenance of chronic phosphate depletion in the western North Pacific.
Florian Ricour, Arthur Capet, Fabrizio D'Ortenzio, Bruno Delille, and Marilaure Grégoire
Biogeosciences, 18, 755–774,Short summary
This paper addresses the phenology of the deep chlorophyll maximum (DCM) in the Black Sea (BS). We show that the DCM forms in March at a density level set by the winter mixed layer. It maintains this location until June, suggesting an influence of the DCM on light and nutrient profiles rather than mere adaptation to external factors. In summer, the DCM concentrates ~55 % of the chlorophyll in a 10 m layer at ~35 m depth and should be considered a major feature of the BS phytoplankton dynamics.
Robyn E. Tuerena, Joanne Hopkins, Raja S. Ganeshram, Louisa Norman, Camille de la Vega, Rachel Jeffreys, and Claire Mahaffey
Biogeosciences, 18, 637–653,Short summary
The Barents Sea is a rapidly changing shallow sea within the Arctic. Here, nitrate, an essential nutrient, is fully consumed by algae in surface waters during summer months. Nitrate is efficiently regenerated in the Barents Sea, and there is no evidence for nitrogen loss from the sediments by denitrification, which is prevalent on other Arctic shelves. This suggests that nitrogen availability in the Barents Sea is largely determined by the supply of nutrients in water masses from the Atlantic.
Biogeosciences, 18, 509–534,Short summary
Biogeochemical-Argo floats are starting to routinely measure ocean chlorophyll, nutrients, oxygen, and pH. This study generated synthetic observations representing two potential Biogeochemical-Argo observing system designs and created a data assimilation scheme to combine them with an ocean model. The proposed system of 1000 floats brought clear benefits to model results, with additional floats giving further benefit. Existing satellite ocean colour observations gave complementary information.
Mark Hague and Marcello Vichi
Biogeosciences, 18, 25–38,Short summary
This paper examines the question of what causes the rapid spring growth of microscopic marine algae (phytoplankton) in the ice-covered ocean surrounding Antarctica. One prominent hypothesis proposes that the melting of sea ice is the primary cause, while our results suggest that this is only part of the explanation. In particular, we show that phytoplankton are able to start growing before the sea ice melts appreciably, much earlier than previously thought.
Arthur Capet, Luc Vandenbulcke, and Marilaure Grégoire
Biogeosciences, 17, 6507–6525,Short summary
The Black Sea is 2000 m deep, but, due to limited ventilation, only about the upper 100 m contains enough oxygen to support marine life such as fish. This oxygenation depth has been shown to be decreasing (1955–2019). Here, we evidence that atmospheric warming induced a clear shift in an important ventilation mechanism. We highlight the impact of this shift on oxygenation. There are important implications for marine life and carbon and nutrient cycling if this new ventilation regime persists.
Tim Rixen, Greg Cowie, Birgit Gaye, Joaquim Goes, Helga do Rosário Gomes, Raleigh R. Hood, Zouhair Lachkar, Henrike Schmidt, Joachim Segschneider, and Arvind Singh
Biogeosciences, 17, 6051–6080,Short summary
The northern Indian Ocean hosts an extensive oxygen minimum zone (OMZ), which intensified due to human-induced global changes. This includes the occurrence of anoxic events on the Indian shelf and affects benthic ecosystems and the pelagic ecosystem structure in the Arabian Sea. Consequences for biogeochemical cycles are unknown, which, in addition to the poor representation of mesoscale features, reduces the reliability of predictions of the future OMZ development in the northern Indian Ocean.
Marion Lagarde, Nolwenn Lemaitre, Hélène Planquette, Mélanie Grenier, Moustafa Belhadj, Pascale Lherminier, and Catherine Jeandel
Biogeosciences, 17, 5539–5561,
Randelle M. Bundy, Alessandro Tagliabue, Nicholas J. Hawco, Peter L. Morton, Benjamin S. Twining, Mariko Hatta, Abigail E. Noble, Mattias R. Cape, Seth G. John, Jay T. Cullen, and Mak A. Saito
Biogeosciences, 17, 4745–4767,Short summary
Cobalt (Co) is an essential nutrient for ocean microbes and is scarce in most areas of the ocean. This study measured Co concentrations in the Arctic Ocean for the first time and found that Co levels are extremely high in the surface waters of the Canadian Arctic. Although the Co primarily originates from the shelf, the high concentrations persist throughout the central Arctic. Co in the Arctic appears to be increasing over time and might be a source of Co to the North Atlantic.
Hannah L. Bourne, James K. B. Bishop, Elizabeth J. Connors, and Todd J. Wood
Revised manuscript accepted for BGShort summary
To learn how the biological carbon pump works in productive coastal upwelling systems, four autonomous Carbon Flux Explorers measured carbon flux through the twilight zone beneath an offshore-flowing filament of biologically productive water. Strikingly different particle classes dominated the carbon fluxes during successive stages of the filament evolution over 30 days. Both flux and transfer efficiency were far greater than expected suggesting an out-sized filament impact in California waters.
Friedrich A. Burger, Jasmin G. John, and Thomas L. Frölicher
Biogeosciences, 17, 4633–4662,Short summary
Ensemble simulations of an Earth system model reveal that ocean acidity extremes have increased in the past few decades and are projected to increase further in terms of frequency, intensity, duration, and volume extent. The increase is not only caused by the long-term ocean acidification due to the uptake of anthropogenic CO2, but also due to changes in short-term variability. The increase in ocean acidity extremes may enhance the risk of detrimental impacts on marine organisms.
Frédéric Gazeau, Céline Ridame, France Van Wambeke, Samir Alliouane, Christian Stolpe, Jean-Olivier Irisson, Sophie Marro, Jean-Michel Grisoni, Guillaume De Liège, Sandra Nunige, Kahina Djaoudi, Elvira Pulido-Villena, Julie Dinasquet, Ingrid Obernosterer, Philippe Catala, and Cécile Guieu
Revised manuscript under review for BG
Christopher Gordon, Katja Fennel, Clark Richards, Lynn K. Shay, and Jodi K. Brewster
Biogeosciences, 17, 4119–4134,Short summary
We describe a method for correcting errors in oxygen optode measurements on autonomous platforms in the ocean. The errors result from the relatively slow response time of the sensor. The correction method includes an in situ determination of the effective response time and requires the time stamps of the individual measurements. It is highly relevant for the BGC-Argo program and also applicable to gliders. We also explore if diurnal changes in oxygen can be obtained from profiling floats.
Bin Wang, Katja Fennel, Liuqian Yu, and Christopher Gordon
Biogeosciences, 17, 4059–4074,Short summary
We assess trade-offs between different types of biological observations, specifically satellite ocean color and BGC-Argo profiles and the benefits of combining both for optimizing a biogeochemical model of the Gulf of Mexico. Using all available observations leads to significant improvements in observed and unobserved variables (including primary production and C export). Our results highlight the significant benefits of BGC-Argo measurements for biogeochemical model optimization and validation.
Bruce L. Greaves, Andrew T. Davidson, Alexander D. Fraser, John P. McKinlay, Andrew Martin, Andrew McMinn, and Simon W. Wright
Biogeosciences, 17, 3815–3835,Short summary
We observed that variation in the Southern Annular Mode (SAM) over 11 years showed a relationship with the species composition of hard-shelled phytoplankton in the seasonal ice zone (SIZ) of the Southern Ocean. Phytoplankton in the SIZ are productive during the southern spring and summer when the area is ice-free, with production feeding most Antarctic life. The SAM is known to be increasing with climate change, and changes in phytoplankton in the SIZ may have implications for higher life forms.
Matthieu Roy-Barman, Lorna Folio, Eric Douville, Nathalie Leblond, Fréderic Gazeau, Matthieu Bressac, Thibaut Wagener, Céline Ridame, Karine Desboeufs, and Cécile Guieu
Revised manuscript accepted for BGShort summary
The release of insoluble elements such as Aluminum (Al), Iron (Fe), Rare Earth Elements (REE), Thorium (Th) and Protactinium (Pa) when Saharan dust fall over the Mediterranean Sea was studied during tank experiments, under present and future climate conditions. Each element exhibited different dissolution kinetics and dissolution fractions (always lower than a few percent). Changes in temperature and/or pH under greenhouse conditions lead to a lower Th release and a higher light REE release.
Vincent Taillandier, Louis Prieur, Fabrizio D'Ortenzio, Maurizio Ribera d'Alcalà, and Elvira Pulido-Villena
Biogeosciences, 17, 3343–3366,Short summary
This study addresses the role played by vertical diffusion in the nutrient enrichment of the Levantine intermediate waters, a process particularly relevant inside thermohaline staircases. Thanks to a high profiling frequency over a 4-year period, BGC-Argo float observations reveal the temporal continuity of the layering patterns encountered during the cruise PEACETIME and their impact on vertical and lateral transfers of nitrate between the deep reservoir and the surface productive zone.
Coraline Leseurre, Claire Lo Monaco, Gilles Reverdin, Nicolas Metzl, Jonathan Fin, Solveig Olafsdottir, and Virginie Racapé
Biogeosciences, 17, 2553–2577,Short summary
In this study, we investigate the evolution of CO2 uptake and ocean acidification in the North Atlantic Subpolar surface water. Our results show an important reduction in the capacity of the ocean to absorb CO2 from the atmosphere (1993–2007), due to a rapid increase in the fCO2 and associated with a rapid decrease in pH. Conversely, data obtained during the last decade (2008–2017) show a stagnation of fCO2 (increasing the ocean sink for CO2) and pH.
Antonio Tovar-Sánchez, Araceli Rodríguez-Romero, Anja Engel, Birthe Zäncker, Franck Fu, Emilio Marañón, María Pérez-Lorenzo, Matthieu Bressac, Thibaut Wagener, Sylvain Triquet, Guillaume Siour, Karine Desboeufs, and Cécile Guieu
Biogeosciences, 17, 2349–2364,Short summary
Residence times of particulate metals derived from aerosol deposition in the Sea Surface Microlayer of the Mediterranean Sea ranged from a couple of minutes (e.g., for Fe) to a few hours (e.g., for Cu). Microbial activity seems to play an important role in in this process and in the concentration and distribution of metals between diferent water layers.
Pieter Demuynck, Toby Tyrrell, Alberto Naveira Garabato, Mark Christopher Moore, and Adrian Peter Martin
Biogeosciences, 17, 2289–2314,Short summary
The availability of macronutrients N and Si is of key importance to sustain life in the Southern Ocean. N and Si are available in abundance at the southern boundary of the Southern Ocean due to constant supply from the deep ocean. In the more northern regions of the Southern Ocean, a decline in macronutrient concentration is noticed, especially strong for Si rather than N. This paper uses a simplified biogeochemical model to investigate processes responsible for this decline in concentration.
Martine Lizotte, Maurice Levasseur, Virginie Galindo, Margaux Gourdal, Michel Gosselin, Jean-Éric Tremblay, Marjolaine Blais, Joannie Charette, and Rachel Hussherr
Biogeosciences, 17, 1557–1581,Short summary
This study brings further support to the premise that the prevalence of younger and thinner icescapes over older and thicker ones in the Canadian High Arctic favors the early development of under-ice microorganisms as well as their production of the climate-relevant gas dimethylsulfide (DMS). Given the rapid rate of climate-driven changes in Arctic sea ice, our results suggest implications for the timing and magnitude of DMS pulses in the Arctic, with ramifications for climate forecasting.
Mark J. Hopwood, Nicolas Sanchez, Despo Polyviou, Øystein Leiknes, Julián Alberto Gallego-Urrea, Eric P. Achterberg, Murat V. Ardelan, Javier Aristegui, Lennart Bach, Sengul Besiktepe, Yohann Heriot, Ioanna Kalantzi, Tuba Terbıyık Kurt, Ioulia Santi, Tatiana M. Tsagaraki, and David Turner
Biogeosciences, 17, 1309–1326,Short summary
Hydrogen peroxide, H2O2, is formed naturally in sunlight-exposed water by photochemistry. At high concentrations it is undesirable to biological cells because it is a stressor. Here, across a range of incubation experiments in diverse marine environments (Gran Canaria, the Mediterranean, Patagonia and Svalbard), we determine that two factors consistently affect the H2O2 concentrations irrespective of geographical location: bacteria abundance and experiment design.
Neil J. Wyatt, Angela Milne, Eric P. Achterberg, Thomas J. Browning, Heather A. Bouman, E. Malcolm S. Woodward, and Maeve C. Lohan
Revised manuscript accepted for BGShort summary
Using data collected during two expeditions to the South Atlantic ocean, we investigated how the interaction between external sources and biological activity influenced the availability of the trace metals zinc and cobalt. This is important as both metals play essential roles in the metabolism and growth of phytoplankton and thus influence primary productivity of the oceans. We found seasonal changes in both processes that helped explain upper ocean trace metal cycling.
Manon Tonnard, Hélène Planquette, Andrew R. Bowie, Pier van der Merwe, Morgane Gallinari, Floriane Desprez de Gésincourt, Yoan Germain, Arthur Gourain, Marion Benetti, Gilles Reverdin, Paul Tréguer, Julia Boutorh, Marie Cheize, François Lacan, Jan-Lukas Menzel Barraqueta, Leonardo Pereira-Contreira, Rachel Shelley, Pascale Lherminier, and Géraldine Sarthou
Biogeosciences, 17, 917–943,Short summary
We investigated the spatial distribution of dissolved Fe during spring 2014, in order to understand the processes influencing the biogeochemical cycle in the North Atlantic. Our results highlighted elevated Fe close to riverine inputs at the Iberian Margin and glacial inputs at the Newfoundland and Greenland margins. Atmospheric deposition appeared to be a minor source of Fe. Convection was an important source of Fe in the Irminger Sea, which was depleted in Fe relative to nitrate.
Carolin R. Löscher, Wiebke Mohr, Hermann W. Bange, and Donald E. Canfield
Biogeosciences, 17, 851–864,Short summary
Oxygen minimum zones (OMZs) are ocean areas severely depleted in oxygen as a result of physical, chemical, and biological processes. Biologically, organic material is produced in the sea surface and exported to deeper waters, where it respires. In the Bay of Bengal (BoB), an OMZ is present, but there are traces of oxygen left. Our study now suggests that this is because one key process, nitrogen fixation, is absent in the BoB, thus preventing primary production and consecutive respiration.
Lothar Stramma, Sunke Schmidtko, Steven J. Bograd, Tsuneo Ono, Tetjana Ross, Daisuke Sasano, and Frank A. Whitney
Biogeosciences, 17, 813–831,Short summary
The influence of climate signals in the Pacific, especially the Pacific Decadal Oscillation and the North Pacific Gyre Oscillation, as well as El Niño–La Niña and an 18.6-year nodal tidal cycle on oxygen and nutrient trends is investigated. At different locations in the Pacific Ocean different climate signals dominate. Hence, not only trends related to warming but also the influence of climate signals need to be investigated to understand oxygen and nutrient changes in the ocean.
Marie-Hélène Radenac, Julien Jouanno, Christine Carine Tchamabi, Mesmin Awo, Bernard Bourlès, Sabine Arnault, and Olivier Aumont
Biogeosciences, 17, 529–545,Short summary
Satellite data and a remarkable set of in situ measurements show a main bloom of microscopic seaweed, the phytoplankton, in summer and a secondary bloom in December in the central equatorial Atlantic. They are driven by a strong vertical supply of nitrate in May–July and a shorter and moderate supply in November. In between, transport of low-nitrate water from the west explains most nitrate losses in the sunlit layer. Horizontal eddy-induced processes also contribute to seasonal nitrate removal.
Andrés S. Rigual Hernández, Thomas W. Trull, Scott D. Nodder, José A. Flores, Helen Bostock, Fátima Abrantes, Ruth S. Eriksen, Francisco J. Sierro, Diana M. Davies, Anne-Marie Ballegeer, Miguel A. Fuertes, and Lisa C. Northcote
Biogeosciences, 17, 245–263,Short summary
Coccolithophores account for a major fraction of the carbonate produced in the world's oceans. However, their contribution in the subantarctic Southern Ocean remains undocumented. We quantitatively partition calcium carbonate fluxes amongst coccolithophore species in the Australian–New Zealand sector of the Southern Ocean. We provide new insights into the importance of species other than Emiliania huxleyi in the carbon cycle and assess their possible response to projected environmental change.
Susana Agustí, Jeffrey W. Krause, Israel A. Marquez, Paul Wassmann, Svein Kristiansen, and Carlos M. Duarte
Biogeosciences, 17, 35–45,Short summary
We found that 24 % of the total diatoms community in the Arctic water column (450 m depth) was located below the photic layer. Healthy diatom communities in active spring–bloom stages remained in the photic layer. Dying diatom communities exported a large fraction of the biomass to the aphotic zone, fuelling carbon sequestration and benthic ecosystems in the Arctic. The results of the study conform to a conceptual model where diatoms grow during the bloom until silicic acid stocks are depleted.
Xinwei Wang, Feixue Fu, Pingping Qu, Joshua D. Kling, Haibo Jiang, Yahui Gao, and David A. Hutchins
Biogeosciences, 16, 4393–4409,Short summary
In this study, we examine the responses of E. huxleyi to a future warmer and more thermally variable ocean. Elevated temperatures and thermal variation have negative effects on growth rate and physiology that are especially pronounced at high temperatures, but high-frequency thermal variation may reduce the risk of extreme high-temperature events. These findings have potentially large implications for ocean productivity and marine biogeochemical cycles under a future changing climate.
Federico Baltar and Gerhard J. Herndl
Biogeosciences, 16, 3793–3799,Short summary
Around half of the global primary production (PP) is produced in the ocean. Here we quantified how much oceanic PP estimates would increase if we included the dark DIC fixation rates (which are usually excluded in the carbon-14 method) into the PP estimation. We found that the inclusion of dark DIC fixation would increase PP estimates by 5–22 %. This represents ca. 1.2 to 11 Pg C yr−1 of newly synthesized organic carbon available for the marine food web.
Renaud Person, Olivier Aumont, Gurvan Madec, Martin Vancoppenolle, Laurent Bopp, and Nacho Merino
Biogeosciences, 16, 3583–3603,Short summary
The Antarctic Ice Sheet is considered a possibly important but largely overlooked source of iron (Fe). Here we explore its fertilization capacity by evaluating the response of marine biogeochemistry to Fe release from icebergs and ice shelves in a global ocean model. Large regional impacts are simulated, leading to only modest primary production and carbon export increases at the scale of the Southern Ocean. Large uncertainties are due to low observational constraints on modeling choices.
Robyn E. Tuerena, Raja S. Ganeshram, Matthew P. Humphreys, Thomas J. Browning, Heather Bouman, and Alexander P. Piotrowski
Biogeosciences, 16, 3621–3635,Short summary
The carbon isotopes in algae can be used to predict food sources and environmental change. We explore how dissolved carbon is taken up by algae in the South Atlantic Ocean and how this affects their carbon isotope signature. We find that cell size controls isotope fractionation. We use our results to investigate how climate change may impact the carbon isotopes in algae. We suggest a shift to smaller algae in this region would decrease the carbon isotope ratio at the base of the food web.
Daniela Niemeyer, Iris Kriest, and Andreas Oschlies
Biogeosciences, 16, 3095–3111,Short summary
Recent studies suggest spatial variations of the marine particle flux length scale. Using a global biogeochemical ocean model, we investigate whether changes in particle size and size-dependent sinking can explain this variation. We address uncertainties by varying aggregate properties and circulation. Both aspects have an impact on the representation of nutrients, oxygen and oxygen minimum zones. The formation and sinking of large aggregates in productive areas lead to deeper flux penetration.
Jamie D. Wilson, Stephen Barker, Neil R. Edwards, Philip B. Holden, and Andy Ridgwell
Biogeosciences, 16, 2923–2936,Short summary
The remains of plankton rain down from the surface ocean to the deep ocean, acting to store CO2 in the deep ocean. We used a model of biology and ocean circulation to explore the importance of this process in different regions of the ocean. The amount of CO2 stored in the deep ocean is most sensitive to changes in the Southern Ocean. As plankton in the Southern Ocean are likely those most impacted by future climate change, the amount of CO2 they store in the deep ocean could also be affected.
Natalie C. Harms, Niko Lahajnar, Birgit Gaye, Tim Rixen, Kirstin Dähnke, Markus Ankele, Ulrich Schwarz-Schampera, and Kay-Christian Emeis
Biogeosciences, 16, 2715–2732,Short summary
The Indian Ocean subtropical gyre is a large oligotrophic area that is likely to adjust to continued warming by increasing stratification, reduced nutrient supply and decreasing biological production. In this study, we investigated concentrations of nutrients and stable isotopes of nitrate. We determine the lateral influence of water masses entering the gyre from the northern Indian Ocean and from the Southern Ocean and quantify the input of nitrogen by N2 fixation into the surface layer.
Yingxu Wu, Mathis P. Hain, Matthew P. Humphreys, Sue Hartman, and Toby Tyrrell
Biogeosciences, 16, 2661–2681,Short summary
This study takes advantage of the GLODAPv2 database to investigate the processes driving the surface ocean dissolved inorganic carbon distribution, with the focus on its latitudinal gradient between the polar oceans and the low-latitude oceans. Based on our quantitative study, we find that temperature-driven CO2 gas exchange and high-latitude upwelling of DIC- and TA-rich deep waters are the two major drivers, with the importance of the latter not having been previously realized.
Qixing Ji, Mark A. Altabet, Hermann W. Bange, Michelle I. Graco, Xiao Ma, Damian L. Arévalo-Martínez, and Damian S. Grundle
Biogeosciences, 16, 2079–2093,Short summary
A strong El Niño event occurred in the Peruvian coastal region in 2015–2016, during which higher sea surface temperatures co-occurred with significantly lower sea-to-air fluxes of nitrous oxide, an important greenhouse gas and ozone depletion agent. Stratified water column during El Niño retained a larger amount of nitrous oxide that was produced via multiple microbial pathways; and intense nitrous oxide effluxes could occur when normal upwelling is resumed after El Niño.
Ulrike Löptien and Heiner Dietze
Biogeosciences, 16, 1865–1881,Short summary
Anthropogenic greenhouse gas emissions trigger complex climate feedbacks. Output form Earth system models provides a basis for related political decision-making. One challenge is to arrive at reliable model parameter estimates for the ocean biogeochemistry module. We illustrate pitfalls through which flaws in the ocean module are masked by wrongly tuning the biogeochemistry and discuss ensuing uncertainties in climate projections.
Arthur Gourain, Hélène Planquette, Marie Cheize, Nolwenn Lemaitre, Jan-Lukas Menzel Barraqueta, Rachel Shelley, Pascale Lherminier, and Géraldine Sarthou
Biogeosciences, 16, 1563–1582,Short summary
The GEOVIDE cruise (May–June 2014, R/V Pourquoi Pas?) aimed to provide a better understanding of trace metal biogeochemical cycles in the North Atlantic. As particles play a key role in the global biogeochemical cycle of trace elements in the ocean, we discuss the distribution of particulate iron (PFe). Lithogenic sources appear to dominate the PFe cycle through margin and benthic inputs.
Jan-Lukas Menzel Barraqueta, Jessica K. Klar, Martha Gledhill, Christian Schlosser, Rachel Shelley, Hélène F. Planquette, Bernhard Wenzel, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 16, 1525–1542,Short summary
We used surface water dissolved aluminium concentrations collected in four different GEOTRACES cruises to determine atmospheric deposition fluxes to the ocean. We calculate atmospheric deposition fluxes for largely under-sampled regions of the Atlantic Ocean and thus provide new constraints for models of atmospheric deposition. The use of the MADCOW model is of major importance as dissolved aluminium is analysed within the GEOTRACES project at high spatial resolution.
Karin F. Kvale, Katherine E. Turner, Angela Landolfi, and Katrin J. Meissner
Biogeosciences, 16, 1019–1034,Short summary
Drivers motivating the evolution of calcifying phytoplankton are poorly understood. We explore differences in global ocean chemistry with and without calcifiers during rapid climate changes. We find the presence of phytoplankton calcifiers stabilizes the volume of low oxygen regions and consequently stabilizes the concentration of nitrate, which is an important nutrient required for photosynthesis. By stabilizing nitrate concentrations, calcifiers improve their growth conditions.
Debany Fonseca-Batista, Xuefeng Li, Virginie Riou, Valérie Michotey, Florian Deman, François Fripiat, Sophie Guasco, Natacha Brion, Nolwenn Lemaitre, Manon Tonnard, Morgane Gallinari, Hélène Planquette, Frédéric Planchon, Géraldine Sarthou, Marc Elskens, Julie LaRoche, Lei Chou, and Frank Dehairs
Biogeosciences, 16, 999–1017,Short summary
Dinitrogen fixation and primary production were investigated using stable isotope incubation experiments along two transects off the Western Iberian Margin in May 2014 close to the end of the phytoplankton spring bloom. We observed substantial N2 fixation activities (up to 1533 µmol N m-2 d-1) associated with a predominance of unicellular cyanobacteria and non-cyanobacterial diazotrophs, which seemed to be promoted by the presence of bloom-derived organic matter and excess phosphorus.
Ludivine Conte, Sophie Szopa, Roland Séférian, and Laurent Bopp
Biogeosciences, 16, 881–902,Short summary
The ocean is a source of atmospheric carbon monoxide, a key component for the oxidizing capacity of the atmosphere. We use a global ocean biogeochemistry model to dynamically assess the oceanic CO budget and its emission to the atmosphere at the global scale. The total emissions of CO to the atmosphere are 4.0 Tg C yr−1. The oceanic CO emission maps produced are relevant for use by atmospheric chemical models, especially to study the oxidizing capacity of the atmosphere above the remote ocean.
Yi Tang, Nolwenn Lemaitre, Maxi Castrillejo, Montserrat Roca-Martí, Pere Masqué, and Gillian Stewart
Biogeosciences, 16, 309–327,Short summary
Oceanographers try to understand the ocean’s role in the global carbon cycle. Trace levels of natural radionuclides can inform this connection and their half-lives provide an estimate of the timing of processes. We used the 210Po and 210Pb pair to examine the export of carbon from the surface ocean to depth along the GEOVIDE GEOTRACES cruise track. We found that the flux was regionally variable, that upwelling was an important regional factor, and that both large and small particles drove flux.
Ambrose, W. G. and Renaud, P. E.: Benthic response to water column productivity patterns: Evidence for benthic-pelagic coupling in the Northeast Water Polynya, J. Geophys. Res., 100, 4411, https://doi.org/10.1029/94JC01982, 1995.
Anderson, M. J.: PERMANOVA: Permutational multivariate analysis of variance, Auckland, Department of Statistics, 2005.
Anderson, L. A. and Sarmiento, J. L.: Redfield ratios of remineralization determined by nutrient data analysis, Global Biogeochem. Cy., 8, 65–80, https://doi.org/10.1029/93GB03318, 1994.
Anderson, M. J., Gorley, R. N., and Clarke, K. R.: PERMANOVA+ for PRIMER: guide to software and statistical methods, PRIMER-E, Plymouth, 2007.
Arrigo, K. R., van Dijken, G., and Pabi, S.: Impact of a shrinking Arctic ice cover on marine primary production, Geophys. Res. Lett., 35, L19603, https://doi.org/10.1029/2008GL035028, 2008.
Arrigo, K. R., Perovich, D. K., Pickart, R. S., Brown, Z. W., van Dijken, G. L., Lowry, K. E., Mills, M. M., Palmer, M. A., Balch, W. M., Bahr, F., Bates, N. R., Benitez-Nelson, C., Bowler, B., Brownlee, E., Ehn, J. K., Frey, K. E., Garley, R., Laney, S. R., Lubelczyk, L., Mathis, J., Matsuoka, A., Mitchell, B. G., Moore, G. W. K., Ortega-Retuerta, E., Pal, S., Polashenski, C. M., Reynolds, R. A., Schieber, B., Sosik, H. M., Stephens, M., and Swift, J. H.: Massive Phytoplankton Blooms Under Arctic Sea Ice, Science, 336, 1408, https://doi.org/10.1126/science.1215065, 2012.
Bauerfeind, E., Garrity, C., Krumbholz, M., Ramseier, R. O., and Voß, M.: Seasonal variability of sediment trap collections in the Northeast Water Polynya. Part 2. Biochemical and microscopic composition of sedimenting matter, J. Mar. Syst., 10, 371–389, https://doi.org/10.1016/S0924-7963(96)00069-3, 1997.
Bauerfeind, E., Leipe, T., and Ramseier, R. O.: Sedimentation at the permanently ice-covered Greenland continental shelf (74°57.7′ N/12°58.7′ W): significance of biogenic and lithogenic particles in particulate matter flux, J. Mar. Syst., 56, 151–166, https://doi.org/10.1016/j.jmarsys.2004.09.007, 2005.
Bauerfeind, E., Nöthig, E.-M., Beszczynska, A., Fahl, K., Kaleschke, L., Kreker, K., Klages, M., Soltwedel, T., Lorenzen, C., and Wegner, J.: Particle sedimentation patterns in the eastern Fram Strait during 2000–2005: Results from the Arctic long-term observatory HAUSGARTEN, Deep-Sea Res. Pt. I, 56, 1471–1487, https://doi.org/10.1016/j.dsr.2009.04.011, 2009.
Belcher, A., Iversen, M., Manno, C., Henson, S. A., Tarling, G. A., and Sanders, R.: The role of particle associated microbes in remineralization of fecal pellets in the upper mesopelagic of the Scotia Sea, Antarctica, Limnol. Oceanogr., 61, 1049–1064, https://doi.org/10.1002/lno.10269, 2016.
Boetius, A. and Damm, E.: Benthic oxygen uptake, hydrolytic potentials and microbial biomass at the Arctic continental slope, Deep-Sea Res. Pt. I, 45, 239–275, https://doi.org/10.1016/S0967-0637(97)00052-6, 1998.
Boetius, A. and Lochte, K.: Regulation of microbial enzymatic degradation of organic matter in deep-sea sediments, Mar. Ecol. Prog. Ser., 104, 299–307, 1994.
Boudreau, B. P.: Diagenetic models and their implementations: Modelling transport and reactions in aquatic sediments with 75 Figs. and 19 Tables, Springer, Berlin, XVI, 414 str., 1997.
Bourgeois, S., Archambault, P., and Witte, U.: Organic matter remineralization in marine sediments: A Pan-Arctic synthesis, Global Biogeochem. Cy., 31, 190–213, https://doi.org/10.1002/2016GB005378, 2017.
Burdige, D. J.: Geochemistry of Marine Sediments, Princeton University Press, Princeton, NJ, xviii, 609, 2006.
Buttigieg, P. L. and Ramette, A.: A guide to statistical analysis in microbial ecology: a community-focused, living review of multivariate data analyses, FEMS Microbiol. Ecol., 90, 543–550, https://doi.org/10.1111/1574-6941.12437, 2014.
Cathalot, C., Rabouille, C., Sauter, E., Schewe, I., Soltwedel, T., and Vopel, K. C.: Benthic Oxygen Uptake in the Arctic Ocean Margins – A Case Study at the Deep-Sea Observatory HAUSGARTEN (Fram Strait), PLoS ONE, 10, e0138339, https://doi.org/10.1371/journal.pone.0138339, 2015.
Cherkasheva, A., Bracher, A., Melsheimer, C., Köberle, C., Gerdes, R., Nöthig, E.-M., Bauerfeind, E., and Boetius, A.: Influence of the physical environment on polar phytoplankton blooms: A case study in the Fram Strait, J. Mar. Syst., 132, 196–207, https://doi.org/10.1016/j.jmarsys.2013.11.008, 2014.
Clarke, K. R. and Gorley, R. N.: Primer v6: User Manual/Tutorial, PRIMER-E, Plymouth, 2006.
Clarke, K. R. and Warwick, R. M.: Similarity-based testing for community pattern: the two-way layout with no replication, Mar. Biol., 118, 167–176, https://doi.org/10.1007/BF00699231, 1994.
Codispoti, L. A., Kelly, V., Thessen, A., Matrai, P., Suttles, S., Hill, V., Steele, M., and Light, B.: Synthesis of primary production in the Arctic Ocean: III. Nitrate and phosphate based estimates of net community production, Prog. Oceanogr., 110, 126–150, https://doi.org/10.1016/j.pocean.2012.11.006, 2013.
Comiso, J. C., Parkinson, C. L., Gersten, R., and Stock, L.: Accelerated decline in the Arctic sea ice cover, Geophys. Res. Lett., 35, L01703, https://doi.org/10.1029/2007GL031972, 2008.
Donis, D., McGinnis, D. F., Holtappels, M., Felden, J., and Wenzhoefer, F.: Assessing benthic oxygen fluxes in oligotrophic deep sea sediments (HAUSGARTEN observatory), Deep-Sea Res. Pt. I, 111, 1–10, https://doi.org/10.1016/j.dsr.2015.11.007, 2016.
Ezraty, R., Girard-Ardhuin, F., Piollé, J.-F., Kaleschke, L., and Heygster, G.: Arctic and Antarctic Sea Ice concentration and Arctic Sea Ice drift estimated from Special Sensor Microwave Data: User's Manual, Version 2.1, Département d'Océanographie Physique et Spatiale, IFREMER (Brest, France) and Institute of Environmental Physics, University of Bremen, 2007.
Fernández-Méndez, M., Katlein, C., Rabe, B., Nicolaus, M., Peeken, I., Bakker, K., Flores, H., and Boetius, A.: Photosynthetic production in the central Arctic Ocean during the record sea-ice minimum in 2012, Biogeosciences, 12, 3525–3549, https://doi.org/10.5194/bg-12-3525-2015, 2015.
Findlay, R. H., King, G. M., and Watling, L.: Efficacy of Phospholipid Analysis in Determining Microbial Biomass in Sediments, Appl. Environ. Microbiol., 55, 2888–2893, 1989.
Flach, E., Muthumbi, A., and Heip, C.: Meiofauna and macrofauna community structure in relation to sediment composition at the Iberian margin compared to the Goban Spur (NE Atlantic), Prog. Oceanogr., 52, 433–457, https://doi.org/10.1016/S0079-6611(02)00018-6, 2002.
Forest, A., Wassmann, P., Slagstad, D., Bauerfeind, E., Nöthig, E.-M., and Klages, M.: Relationships between primary production and vertical particle export at the Atlantic-Arctic boundary (Fram Strait, HAUSGARTEN), Polar Biol., 33, 1733–1746, https://doi.org/10.1007/s00300-010-0855-3, 2010.
Glud, R. N.: Oxygen dynamics of marine sediments, Mar. Biol. Res., 4, 243–289, https://doi.org/10.1080/17451000801888726, 2008.
Glud, R. N., Gundersen, J. K., Jørgensen, B. B., Revsbech, N. P., and Schulz, H. D.: Diffusive and total oxygen uptake of deep-sea sediments in the eastern South Atlantic Ocean:in situ and laboratory measurements, Deep-Sea Res. Pt. I, 41, 1767–1788, https://doi.org/10.1016/0967-0637(94)90072-8, 1994.
Górska, B., Grzelak, K., Kotwicki, L., Hasemann, C., Schewe, I., Soltwedel, T., and Włodarska-Kowalczuk, M.: Bathymetric variations in vertical distribution patterns of meiofauna in the surface sediments of the deep Arctic ocean (HAUSGARTEN, Fram strait), Deep-Sea Res. Pt. I, 91, 36–49, https://doi.org/10.1016/j.dsr.2014.05.010, 2014.
Gradinger, R.: Sea-ice algae: Major contributors to primary production and algal biomass in the Chukchi and Beaufort Seas during May/June 2002, Deep-Sea Res. Pt. II, 56, 1201–1212, https://doi.org/10.1016/j.dsr2.2008.10.016, 2009.
Graeve, M. and Ludwichowski, K.-U.: Inorganic nutrients measured on water bottle samples during POLARSTERN cruise PS85 (ARK-XXVIII/2), PANGAEA, doi.org/10.1594/PANGAEA.882217, 2017a.
Graeve, M. and Ludwichowski, K.-U.: Inorganic nutrients measured on water bottle samples during POLARSTERN cruise PS93.2 (ARK-XXIX/2.2), PANGAEA, doi.org/ 10.1594/PANGAEA.884130, 2017b.
Graf, G.: Benthic-pelagic coupling in a deep-sea benthic community, Nature, 341, 437–439, https://doi.org/10.1038/341437a0, 1989.
Graf, G., Gerlach, S., Linke, P., Queisser, W., Ritzrau, W., Scheltz, A., Thomsen, L., and Witte, U.: Benthic-pelagic coupling in the Greenland-Norwegian Sea and its effect on the geological record, Geol. Rundsch., 84, 49–58, https://doi.org/10.1007/BF00192241, 1995.
Grebmeier, J. M. and Barry, J. P.: Chapter 11 Benthic Processes in Polynyas, in: Polynyas: Windows to the World, Elsevier Oceanography Series, Elsevier, 363–390, 2007.
Grebmeier, J. M., McRoy, P. C., and Feder, H. M.: Pelagic-benthic coupling on the shelf of the northern Bering and Chukchi Seas. I. Food supply source and benthic biomass, Mar. Ecol. Prog. Ser., 48, 57–67, 1988.
Greiser, N. and Faubel, A.: Biotic factors, in: Introduction to the study of meiofauna, edited by: Higgins, R. P. and Thiel, H., Smithsonian Institution Press, Washington, DC, 79–114, 1988.
Harada, N.: Review: Potential catastrophic reduction of sea ice in the western Arctic Ocean: Its impact on biogeochemical cycles and marine ecosystems, Glob. Planet. Change, 136, 1–17, https://doi.org/10.1016/j.gloplacha.2015.11.005, 2015.
Heip, C., Vincx, M., and Vranken, G.: The Ecology of marine nematodes, in: Oceanography and Marine Biology: An Annual Review, edited by: Barnes, M., Oceanography and Marine Biology – An Annual Review, 23, 399–489, 1985.
Henson, S. A., Beaulieu, C., and Lampitt, R.: Observing climate change trends in ocean biogeochemistry: when and where, Glob. Change Biol., 22, 1561–1571, https://doi.org/10.1111/gcb.13152, 2016.
Hobbie, J. E., Daley, R. J., and Jasper, S.: Use of nuclepore filters for counting bacteria by fluorescence microscopy, Appl. Environ. Microbiol., 33, 1225–1228, 1977.
Hoffmann, R., Braeckman, U., and Wenzhöfer, F.: In situ and ex situ oxygen profiles and resulting diffusive oxygen uptake; in situ and ex situ total oxygen flux; benthic community density and biomass, bioturbation potential and solute exchange in the Hausgarten area, Arctic Fram Strait (2014/2015), PANGAEA, https://doi.org/10.1594/PANGAEA.883410, 2017.
Hop, H., Falk-Petersen, S., Svendsen, H., Kwasniewski, S., Pavlov, V., Pavlova, O., and Søreide, J. E.: Physical and biological characteristics of the pelagic system across Fram Strait to Kongsfjorden, Prog. Oceanogr., 71, 182–231, https://doi.org/10.1016/j.pocean.2006.09.007, 2006.
Jacob, M., Soltwedel, T., Boetius, A., Ramette, A., and Gilbert, J. A.: Biogeography of deep-sea benthic bacteria at regional scale (LTER HAUSGARTEN, Fram Strait, Arctic), PLoS ONE, 8, e72779, https://doi.org/10.1371/journal.pone.0072779, 2013.
Jahnke, R. A.: The global ocean flux of particulate organic carbon: areal distribution and magnitude, Glob Biogeochem. Cy., 10, 71–88, https://doi.org/10.1029/95GB03525, 1996.
Jahnke, R. A., Reimers, C. E., Craven, D. B.: Intensification of recycling of organic matter at the sea floor near ocean margins, Nature, 348, 50–54, https://doi.org/10.1038/348050a0, 1990.
Jones, D. O., Yool, A., Wei, C.-L., Henson, S. A., Ruhl, H. A., Watson, R. A., and Gehlen, M.: Global reductions in seafloor biomass in response to climate change, Glob. Change Biol., 20, 1861–1872, https://doi.org/10.1111/gcb.12480, 2014.
Kirk, J. T. O.: Light and photosynthesis in aquatic ecosystems, Third edition, Cambridge University Press, Cambridge, 645 pp., 2011.
Klages, M., Boetius, A., Christensen, J. P., Deubel, H., Piepenburg, D., Schewe, I., and Soltwedel, T.: The Benthos of Arctic Seas and its Role for the Organic Carbon Cycle at the Seafloor, in: The Organic Carbon Cycle in the Arctic Ocean, edited by: Stein, R. and MacDonald, R. W., Springer Berlin Heidelberg, Berlin, Heidelberg, 139–167, 2004.
Köster, M., Jensen, P., and Meyer-Reil, L.-A.: Hydrolytic Activities of Organisms and Biogenic Structures in Deep-Sea Sediments, in: Microbial Enzymes in Aquatic Environments, edited by: Chróst, R. J. Springer New York, New York, NY, 298–310, 1991.
Krumpen, T.: Sea Ice and Atmospheric Conditions at HAUSGARTEN between 2000–2016 (daily resolution), link to model results, PANGAEA, 2017.
Krumpen, T., Gerdes, R., Haas, C., Hendricks, S., Herber, A., Selyuzhenok, V., Smedsrud, L., and Spreen, G.: Recent summer sea ice thickness surveys in Fram Strait and associated ice volume fluxes, The Cryosphere, 10, 523–534, https://doi.org/10.5194/tc-10-523-2016, 2016.
Kruskal, J. B.: Multidimensional scaling by optimizing goodness of fit to a nonmetric hypothesis, Psychometrika, 29, 1–27, https://doi.org/10.1007/BF02289565, 1964.
Lalande, C., Nöthig, E.-M., Bauerfeind, E., Hardge, K., Beszczynska-Möller, A., and Fahl, K.: Lateral supply and downward export of particulate matter from upper waters to the seafloor in the deep eastern Fram Strait, Deep-Sea Res. Pt. I, 114, 78–89, https://doi.org/10.1016/j.dsr.2016.04.014, 2016.
Li, Y.-H. and Gregory, S.: Diffusion of ions in sea water and in deep-sea sediments, Geochim. Cosmochim. Ac., 38, 703–714, https://doi.org/10.1016/0016-7037(74)90145-8, 1974.
Manley, T. O.: Branching of Atlantic Water within the Greenland-Spitsbergen Passage: An estimate of recirculation, J. Geophys. Res., 100, 20627, https://doi.org/10.1029/95JC01251, 1995.
Mauritzen, C., Hansen, E., Andersson, M., Berx, B., Beszczynska-Möller, A., Burud, I., Christensen, K. H., Debernard, J., Steur, L. de, Dodd, P., Gerland, S., Godøy, Ø., Hansen, B., Hudson, S., Høydalsvik, F., Ingvaldsen, R., Isachsen, P. E., Kasajima, Y., Koszalka, I., Kovacs, K. M., Køltzow, M., LaCasce, J., Lee, C. M., Lavergne, T., Lydersen, C., Nicolaus, M., Nilsen, F., Nøst, O. A., Orvik, K. A., Reigstad, M., Schyberg, H., Seuthe, L., Skagseth, Ø., Skarðhamar, J., Skogseth, R., Sperrevik, A., Svensen, C., Søiland, H., Teigen, S. H., Tverberg, V., and Wexels Riser, C.: Closing the loop – Approaches to monitoring the state of the Arctic Mediterranean during the International Polar Year 2007–2008, Prog. Oceanogr., 90, 62–89, https://doi.org/10.1016/j.pocean.2011.02.010, 2011.
Neukermans, G., Oziel, L., and Babin, M.: Increased intrusion of warming Atlantic water leads to rapid expansion of temperate phytoplankton in the Arctic, Glob. Change Biol., 24, 2545–2553, https://doi.org/10.1111/gcb.14075, 2018.
Nicolaus, M., Katlein, C., Maslanik, J., and Hendricks, S.: Changes in Arctic sea ice result in increasing light transmittance and absorption, Geophys. Res. Lett., 39, L24501, https://doi.org/10.1029/2012GL053738, 2012.
Pabi, S., vanDijken, G. L., and Arrigo, K. R.: Primary production in the Arctic Ocean, 1998–2006, J. Geophys. Res., 113, C08005, https://doi.org/10.1029/2007JC004578, 2008.
Piepenburg, D., Ambrose, W. G., Brandt, A., Renaud, P. E., Ahrens, M. J., and Jensen, P.: Benthic community patterns reflect water column processes in the Northeast Water polynya (Greenland), J. Mar. Syst., 10, 467–482, https://doi.org/10.1016/S0924-7963(96)00050-4, 1997.
Platt, T., Harrison, W. G., Lewis, M. R., Li, W. K.W., Sathyendranath, S., Smith, R. E., and Venzina, A. F.: Biological production of the oceans: the case of a concensus, Mar. Ecol. Prog. Ser., 52, 77–88, 1989.
Queirós, A. M., Birchenough, Silvana N. R., Bremner, J., Godbold, J. A., Parker, R. E., Romero-Ramirez, A., Reiss, H., Solan, M., Somerfield, P. J., van Colen, C., van Hoey, G., and Widdicombe, S.: A bioturbation classification of European marine infaunal invertebrates, Ecol. Evol., 3, 3958–3985, https://doi.org/10.1002/ece3.769, 2013.
Quéric, N.-V., Soltwedel, T., and Arntz, W. E.: Application of a rapid direct viable count method to deep-sea sediment bacteria, J. Microbiol. Method., 57, 351–367, https://doi.org/10.1016/j.mimet.2004.02.005, 2004.
Redfield, A. C.: On the Proportions of Organic Derivatives in Sea Water and Their Relation to the Composition of Plankton, University Press of Liverpool, 1934.
Reimers, C. E.: An in situ microprofiling instrument for measuring interfacial pore water gradients: methods and oxygen profiles from the North Pacific Ocean, Deep-Sea Res. Pt. A, 34, 2019–2035, https://doi.org/10.1016/0198-0149(87)90096-3, 1987.
Renaud, P. E., Morata, N., Ambrose, W. G., Bowie, J. J., and Chiuchiolo, A.: Carbon cycling by seafloor communities on the eastern Beaufort Sea shelf, J. Exp. Mar. Biol. Ecol., 349, 248–260, https://doi.org/10.1016/j.jembe.2007.05.021, 2007.
Renaud, P. E., Morata, N., Carroll, M. L., Denisenko, S. G., and Reigstad, M.: Pelagic–benthic coupling in the western Barents Sea: Processes and time scales, Deep-Sea Res. Pt. II, 55, 2372–2380, https://doi.org/10.1016/j.dsr2.2008.05.017, 2008.
Renner, A. H., Gerland, S., Haas, C., Spreen, G., Beckers, J. F., Hansen, E., Nicolaus, M., and Goodwin, H.: Evidence of Arctic sea ice thinning from direct observations, Geophys. Res. Lett., 41, 5029–5036, https://doi.org/10.1002/2014GL060369, 2014.
Revsbech, N. P.: An oxygen microsensor with a guard cathode, Limnol. Oceangr., 34, 474–478, https://doi.org/10.4319/lo.1989.34.2.0474, 1989.
Rullkötter, J.: Organic Matter: The Driving Force for Early Diagenesis, in: Marine Geochemistry, edited by: Schulz, H. D. and Zabel, M., Springer Berlin Heidelberg, Berlin, Heidelberg, 125–168, 2006.
Sakshaug, E.: Primary and Secondary Production in the Arctic Seas, in: The Organic Carbon Cycle in the Arctic Ocean, edited by: Stein, R. and MacDonald, R. W., Springer Berlin Heidelberg, Berlin, Heidelberg, 57–81, 2004.
Sauter, E. J., Schlüter, M., and Suess, E.: Organic carbon flux and remineralization in surface sediments from the northern North Atlantic derived from pore-water oxygen microprofiles, Deep-Sea Res. Pt. I, 48, 529–553, https://doi.org/10.1016/S0967-0637(00)00061-3, 2001.
Schauer, U., Fahrbach, E., Osterhus, S. and Rohardt, G.: Arctic warming through the Fram Strait: Oceanic heat transport from 3 years of measurements, J. Geophys. Res., 109, C06026, https://doi.org/10.1029/2003JC001823, 2004.
Schewe, I. and Soltwedel, T.: Benthic response to ice-edge-induced particle flux in the Arctic Ocean, Pol. Biol., 26, 610–620, https://doi.org/10.1007/s00300-003-0526-8, 2003.
Schulz, H. D.: Quantification of Early Diagenesis: Dissolved Constituents in Pore Water and Signals in the Solid Phase, in: Marine Geochemistry, edited by: Schulz, H. D. and Zabel, M., Springer Berlin Heidelberg, Berlin, Heidelberg, 73–124, 2006.
Shuman, F. R. and Lorenzen, C. J.: Quantitative degradation of chlorophyll by a marine herbivore, Limnol. Oceangr., 20, 580–586, https://doi.org/10.4319/lo.1975.20.4.0580, 1975.
Smith, C. R., De Leo, F. C., Bernardino, A. F., Sweetman, A. K., and Arbizu, P. M.: Abyssal food limitation, ecosystem structure and climate change, Trends Ecol. Evol., 23, 518–528, https://doi.org/10.1016/j.tree.2008.05.002, 2008.
Smith, K. L., Ruhl, H. A., Kahru, M., Huffard, C. L., and Sherman, A. D.: Deep ocean communities impacted by changing climate over 24 y in the abyssal northeast Pacific Ocean, P. Natl. Acad. Sci., 110, 19838–19841, https://doi.org/10.1073/pnas.1315447110, 2013.
Smith, K. L., Huffard, C. L., Sherman, A. D., and Ruhl, H. A.: Decadal Change in Sediment Community Oxygen Consumption in the Abyssal Northeast Pacific, Aquat. Geochem., 22, 401–417, https://doi.org/10.1007/s10498-016-9293-3, 2016.
Soltwedel, T., Bauerfeind, E., Bergmann, M., Budaeva, N., Hoste, E., Jaeckisch, N., Juterzenka, K. von, Matthiesson, J., Moekievsky, V., Nöthig, E.-M., Quéric, N.-V., Sablotny, B., Sauter, E., Schewe, I., Urban-Malinga, B., Wegner, J., Maria Wlodarska-Kowalczuk, M., and Klages, M.: HAUSGARTEN: Multidisciplinary Investigations at a Deep-Sea, Long-Term Observatory in the Arctic Ocean, Oceanography, 18, 46–61, https://doi.org/10.5670/oceanog.2005.24, 2005.
Soltwedel, T., Bauerfeind, E., Bergmann, M., Bracher, A., Budaeva, N., Busch, K., Cherkasheva, A., Fahl, K., Grzelak, K., Hasemann, C., Jacob, M., Kraft, A., Lalande, C., Metfies, K., Nöthig, E.-M., Meyer, K., Quéric, N.-V., Schewe, I., Włodarska-Kowalczuk, M., and Klages, M.: Natural variability or anthropogenically-induced variation? Insights from 15 years of multidisciplinary observations at the arctic marine LTER site HAUSGARTEN, Ecol. Indic., 65, 89–102, https://doi.org/10.1016/j.ecolind.2015.10.001, 2015.
Spielhagen, R. F., Müller, J., Wagner, A., Werner, K., Lohmann, G., Prange, M., and Stein, R.: Holocene Environmental Variability in the Arctic Gateway, in: Integrated Analysis of Interglacial Climate Dynamics (INTERDYNAMIC), edited by: Schulz, M. and Paul, A., SpringerBriefs in Earth System Sciences, Springer International Publishing, Cham, 37–42, 2015.
Spreen, G., Kaleschke, L., and Heygster, G.: Sea ice remote sensing using AMSR-E 89-GHz channels, J. Geophys. Res., 113, C02S03, https://doi.org/10.1029/2005JC003384, 2008.
Takahashi, T., Broecker, W. S., and Langer, S.: Redfield ratio based on chemical data from isopycnal surfaces, J. Geophys. Res., 90, 6907–6924, https://doi.org/10.1029/JC090iC04p06907, 1985.
Thamdrup, B. and Canfield, D. E.: Benthic Respiration in Aquatic Sediments, in: Methods in Ecosystem Science, edited by: Sala, O. E., Jackson, R. B., Mooney, H. A., and Howarth, R. W., Springer New York, New York, NY, 86–103, 2000.
Thiel, H.: Benthos in Upwelling Regions, in: Upwelling Ecosystems, edited by: Boje, R. and Tomczak, M., Springer Berlin Heidelberg, Berlin, Heidelberg, 124–138, 1978.
Tremblay, J.-É., Simpson, K., Martin, J., Miller, L., Gratton, Y., Barber, D., and Price, N. M.: Vertical stability and the annual dynamics of nutrients and chlorophyll fluorescence in the coastal, southeast Beaufort Sea, J. Geophys. Res., 113, C07S90, https://doi.org/10.1029/2007JC004547, 2008.
Vanreusel, A., Vincx, M., Schram, D., and van Gansbeke, D.: On the Vertical Distribution of the Metazoan Meiofauna in Shelf Break and Upper Slope Habitats of the NE Atlantic, Int. Revue Ges. Hydrobiol. Hydrogr., 80, 313–326, https://doi.org/10.1002/iroh.19950800218, 1995.
Vonk, J. E., Tank, S. E., Bowden, W. B., Laurion, I., Vincent, W. F., Alekseychik, P., Amyot, M., Billet, M. F., Canário, J., Cory, R. M., Deshpande, B. N., Helbig, M., Jammet, M., Karlsson, J., Larouche, J., MacMillan, G., Rautio, M., Walter Anthony, K. M., and Wickland, K. P.: Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems, Biogeosciences, 12, 7129–7167, https://doi.org/10.5194/bg-12-7129-2015, 2015.
van Oevelen, D., Bergmann, M., Soetaert, K., Bauerfeind, E., Hasemann, C., Klages, M., Schewe, I., Soltwedel, T., and Budaeva, N. E.: Carbon flows in the benthic food web at the deep-sea observatory HAUSGARTEN (Fram Strait), Deep-Sea Res. Pt. I, 58, 1069–1083, https://doi.org/10.1016/j.dsr.2011.08.002, 2011.
Walsh, J. E., Chapman, W. L., and Fetterer F.: Gridded monthly sea ice extent and concentration, 1850 Onward, Version 1, NSIDC: National Snow and Ice Data Center (Boulder, Colorado USA), available at: https://doi.org/10.7265/N5833PZ5 (last access: 13 August 2018), 2015.
Wassmann, P.: Arctic marine ecosystems in an era of rapid climate change, Prog. Oceanogr., 90, 1–17, https://doi.org/10.1016/j.pocean.2011.02.002, 2011.
Wassmann, P., Duarte, C.M., Agustí, S., and Sejr, M. K.: Footprints of climate change in the Arctic marine ecosystem, Glob. Change Biol., 17, 1235–1249, https://doi.org/10.1111/j.1365-2486.2010.02311.x, 2011
Wenzhöfer, F. and Glud, R. N.: Benthic carbon mineralization in the Atlantic: a synthesis based on in situ data from the last decade, Deep-Sea Res. Pt. I, 49, 1255–1279, https://doi.org/10.1016/S0967-0637(02)00025-0, 2002.
Wheatcroft, R. A.: Experimental tests for particle size-dependent bioturbation in the deep ocean, Limnol. Oceanogr., 37, 90–104, https://doi.org/10.4319/lo.1992.37.1.0090, 1992.
Winkler, L. W.: Die Bestimmung des im Wasser gelösten Sauerstoffes, Ber. Dtsch. Chem. Ges., 21, 2843–2854, https://doi.org/10.1002/cber.188802102122, 1888.
Witte, U., Wenzhöfer, F., Sommer, S., Boetius, A., Heinz, P., Aberle, N., Sand, M., Cremer, A., Abraham, W.-R., Jørgensen, B. B., and Pfannkuche, O.: In situ experimental evidence of the fate of a photodetritus pulse at the abyssal sea floor, Nature, 424, 763–766, https://doi.org/10.1038/nature01799, 2003.
Our study links surface sea-ice cover and benthic oxygen fluxes in the Fram Strait via primary production, food supply, benthic community, and their functions. We show that sea-ice cover and water depth are the most important factors influencing the ecosystem. However, in water depths > 1500 m, the effect of sea ice fades out. Further, we discuss primary production and benthic remineralization patterns and developed a potential scenario for the benthic remineralization in a future Arctic Ocean.
Our study links surface sea-ice cover and benthic oxygen fluxes in the Fram Strait via primary...