Journal articles: 'Carbon biological pump'

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Silkin, Vladimir A., Oleg I. Podymov, and Anna V. Lifanchuk. "Biological carbon pump in the Black Sea." Hydrosphere Еcology (Экология гидросферы), no. 2(8) (December 2022): 69–92. http://dx.doi.org/10.33624/2587-9367-2022-2(8)-69-92.

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In the northeastern part of the Black Sea, the biological carbon pump is represented by both organic and carbonate pumps. The organic carbon pump consists of small-cell diatoms (mainly Pseudo-nitzschia pseudodelicatissima) and large-cell diatoms (Pseudosolenia calcar-avis and Proboscia alata). The carbonate pump is represented by only one species of cococcolithophore, Emiliania huxleyi. These species form intense blooms that require characteristic hydrological and hydrochemical conditions. The seasonal dynamics of the biological carbon pump is as follows: organic pump (spring) → carbonate pump (late spring and early summer) → organic pump (summer and autumn). An exception is the long-term dynamics of carbon concentration, and no significant carbon growth trends have been identified. During the intensification of the work of the carbonate pump, partial concentrations of carbon in water, increased relative to the atmosphere, and an increased influence of the organic pump on high partial pressure are released. In late spring and early summer, CO2 is released in the Black Sea, as a result, absorption increases in summer. The carbonate pump arises with a greater arrival at sea.

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Pautova, Larisa A., and Vladimir A. Silkin. "Biological carbon pump in the ocean and phytoplankton structure." Hydrosphere Еcology (Экология гидросферы), no. 1(3) (2019): 1–12. http://dx.doi.org/10.33624/2587-9367-2019-1(3)-1-12.

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The process of carbon transfer from the atmosphere to the ocean floor is determined by three different pumps in nature: a solubility pump, an organic pump and a carbonate pump. The latter two are of biological nature. Phytoplankton is a key mediator of organic and carbonate pumps. Depending on its structure, either an organic pump or a carbonate pump will dominate. The structure of the phytoplankton community is formed depending on the hydrophysical and hydrochemical conditions in the ocean. An important regulator of a biological carbon pump is the intensity of the processes in the carbon cycle, operating in the photic zone. The degree of closure of this cycle depends on the structure of the food chain. The increasing complexity of the food chain by adding organisms of high trophic levels reduces the efficiency of the carbon pump. Conversely, the simplification of such a structure increases the flow of organic carbon to the ocean floor.

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Hamme, Roberta C., David P. Nicholson, William J. Jenkins, and Steven R. Emerson. "Using Noble Gases to Assess the Ocean's Carbon Pumps." Annual Review of Marine Science 11, no. 1 (January 3, 2019): 75–103. http://dx.doi.org/10.1146/annurev-marine-121916-063604.

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Natural mechanisms in the ocean, both physical and biological, concentrate carbon in the deep ocean, resulting in lower atmospheric carbon dioxide. The signals of these carbon pumps overlap to create the observed carbon distribution in the ocean, making the individual impact of each pump difficult to disentangle. Noble gases have the potential to directly quantify the physical carbon solubility pump and to indirectly improve estimates of the biological organic carbon pump. Noble gases are biologically inert, can be precisely measured, and span a range of physical properties. We present dissolved neon, argon, and krypton data spanning the Atlantic, Southern, Pacific, and Arctic Oceans. Comparisons between deep-ocean observations and models of varying complexity enable the rates of processes that control the carbon solubility pump to be quantified and thus provide an important metric for ocean model skill. Noble gases also provide a powerful means of assessing air–sea gas exchange parameterizations.

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Birch, Heather, Daniela N. Schmidt, Helen K. Coxall, Dick Kroon, and Andy Ridgwell. "Ecosystem function after the K/Pg extinction: decoupling of marine carbon pump and diversity." Proceedings of the Royal Society B: Biological Sciences 288, no. 1953 (June 23, 2021): 20210863. http://dx.doi.org/10.1098/rspb.2021.0863.

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The ocean biological pump is the mechanism by which carbon and nutrients are transported to depth. As such, the biological pump is critical in the partitioning of carbon dioxide between the ocean and atmosphere, and the rate at which that carbon can be sequestered through burial in marine sediments. How the structure and function of planktic ecosystems in the ocean govern the strength and efficiency of the biological pump and its resilience to disruption are poorly understood. The aftermath of the impact at the Cretaceous/Palaeogene (K/Pg) boundary provides an ideal opportunity to address these questions as both the biological pump and marine plankton size and diversity were fundamentally disrupted. The excellent fossil record of planktic foraminifera as indicators of pelagic-biotic recovery combined with carbon isotope records tracing biological pump behaviour, show that the recovery of ecological traits (diversity, size and photosymbiosis) occurred much later (approx. 4.3 Ma) than biological pump recovery (approx. 1.8 Ma). We interpret this decoupling of diversity and the biological pump as an indication that ecosystem function had sufficiently recovered to drive an effective biological pump, at least regionally in the South Atlantic.

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Ödalen, Malin, Jonas Nycander, Kevin I. C. Oliver, Laurent Brodeau, and Andy Ridgwell. "The influence of the ocean circulation state on ocean carbon storage and CO2 drawdown potential in an Earth system model." Biogeosciences 15, no. 5 (March 6, 2018): 1367–93. http://dx.doi.org/10.5194/bg-15-1367-2018.

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Abstract. During the four most recent glacial cycles, atmospheric CO2 during glacial maxima has been lowered by about 90–100 ppm with respect to interglacials. There is widespread consensus that most of this carbon was partitioned in the ocean. It is, however, still debated which processes were dominant in achieving this increased carbon storage. In this paper, we use an Earth system model of intermediate complexity to explore the sensitivity of ocean carbon storage to ocean circulation state. We carry out a set of simulations in which we run the model to pre-industrial equilibrium, but in which we achieve different states of ocean circulation by changing forcing parameters such as wind stress, ocean diffusivity and atmospheric heat diffusivity. As a consequence, the ensemble members also have different ocean carbon reservoirs, global ocean average temperatures, biological pump efficiencies and conditions for air–sea CO2 disequilibrium. We analyse changes in total ocean carbon storage and separate it into contributions by the solubility pump, the biological pump and the CO2 disequilibrium component. We also relate these contributions to differences in the strength of the ocean overturning circulation. Depending on which ocean forcing parameter is tuned, the origin of the change in carbon storage is different. When wind stress or ocean diapycnal diffusivity is changed, the response of the biological pump gives the most important effect on ocean carbon storage, whereas when atmospheric heat diffusivity or ocean isopycnal diffusivity is changed, the solubility pump and the disequilibrium component are also important and sometimes dominant. Despite this complexity, we obtain a negative linear relationship between total ocean carbon and the combined strength of the northern and southern overturning cells. This relationship is robust to different reservoirs dominating the response to different forcing mechanisms. Finally, we conduct a drawdown experiment in which we investigate the capacity for increased carbon storage by artificially maximising the efficiency of the biological pump in our ensemble members. We conclude that different initial states for an ocean model result in different capacities for ocean carbon storage due to differences in the ocean circulation state and the origin of the carbon in the initial ocean carbon reservoir. This could explain why it is difficult to achieve comparable responses of the ocean carbon pumps in model inter-comparison studies in which the initial states vary between models. We show that this effect of the initial state is quantifiable. The drawdown experiment highlights the importance of the strength of the biological pump in the control state for model studies of increased biological efficiency.

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Jónasdóttir, Sigrún Huld, André W. Visser, Katherine Richardson, and Michael R. Heath. "Seasonal copepod lipid pump promotes carbon sequestration in the deep North Atlantic." Proceedings of the National Academy of Sciences 112, no. 39 (September 3, 2015): 12122–26. http://dx.doi.org/10.1073/pnas.1512110112.

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Estimates of carbon flux to the deep oceans are essential for our understanding of global carbon budgets. Sinking of detrital material (“biological pump”) is usually thought to be the main biological component of this flux. Here, we identify an additional biological mechanism, the seasonal “lipid pump,” which is highly efficient at sequestering carbon into the deep ocean. It involves the vertical transport and metabolism of carbon rich lipids by overwintering zooplankton. We show that one species, the copepod Calanus finmarchicus overwintering in the North Atlantic, sequesters an amount of carbon equivalent to the sinking flux of detrital material. The efficiency of the lipid pump derives from a near-complete decoupling between nutrient and carbon cycling—a “lipid shunt,” and its direct transport of carbon through the mesopelagic zone to below the permanent thermocline with very little attenuation. Inclusion of the lipid pump almost doubles the previous estimates of deep-ocean carbon sequestration by biological processes in the North Atlantic.

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Ducklow, Hugh, Deborah Steinberg, and Ken Buesseler. "Upper Ocean Carbon Export and the Biological Pump." Oceanography 14, no. 4 (2001): 50–58. http://dx.doi.org/10.5670/oceanog.2001.06.

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Bishop, James. "Autonomous Observations of the Ocean Biological Carbon Pump." Oceanography 22, no. 2 (June 1, 2009): 182–93. http://dx.doi.org/10.5670/oceanog.2009.48.

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9

Sanders, Richard, Stephanie A. Henson, Marja Koski, Christina L. De La Rocha, Stuart C. Painter, Alex J. Poulton, Jennifer Riley, et al. "The Biological Carbon Pump in the North Atlantic." Progress in Oceanography 129 (December 2014): 200–218. http://dx.doi.org/10.1016/j.pocean.2014.05.005.

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Pinti, Jérôme, Tim DeVries, Tommy Norin, Camila Serra-Pompei, Roland Proud, David A. Siegel, Thomas Kiørboe, et al. "Model estimates of metazoans' contributions to the biological carbon pump." Biogeosciences 20, no. 5 (March 14, 2023): 997–1009. http://dx.doi.org/10.5194/bg-20-997-2023.

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Abstract. The daily vertical migrations of fish and other metazoans actively transport organic carbon from the ocean surface to depth, contributing to the biological carbon pump. We use an oxygen-constrained, game-theoretic food-web model to simulate diel vertical migrations and estimate near-global (global ocean minus coastal areas and high latitudes) carbon fluxes and sequestration by fish and zooplankton due to respiration, fecal pellets, and deadfalls. Our model provides estimates of the carbon export and sequestration potential for a range of pelagic functional groups, despite uncertain biomass estimates of some functional groups. While the export production of metazoans and fish is modest (∼20 % of global total), we estimate that their contribution to carbon sequestered by the biological pump (∼800 PgC) is conservatively more than 50 % of the estimated global total (∼1300 PgC) and that they have a significantly longer sequestration timescale (∼250 years) than previously reported for other components of the biological pump. Fish and multicellular zooplankton contribute about equally to this sequestered carbon pool. This essential ecosystem service could be at risk from both unregulated fishing on the high seas and ocean deoxygenation due to climate change.

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Tagliabue, Alessandro, and Joseph Resing. "Impact of hydrothermalism on the ocean iron cycle." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2081 (November 28, 2016): 20150291. http://dx.doi.org/10.1098/rsta.2015.0291.

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As the iron supplied from hydrothermalism is ultimately ventilated in the iron-limited Southern Ocean, it plays an important role in the ocean biological carbon pump. We deploy a set of focused sensitivity experiments with a state of the art global model of the ocean to examine the processes that regulate the lifetime of hydrothermal iron and the role of different ridge systems in governing the hydrothermal impact on the Southern Ocean biological carbon pump. Using GEOTRACES section data, we find that stabilization of hydrothermal iron is important in some, but not all regions. The impact on the Southern Ocean biological carbon pump is dominated by poorly explored southern ridge systems, highlighting the need for future exploration in this region. We find inter-basin differences in the isopycnal layer onto which hydrothermal Fe is supplied between the Atlantic and Pacific basins, which when combined with the inter-basin contrasts in oxidation kinetics suggests a muted influence of Atlantic ridges on the Southern Ocean biological carbon pump. Ultimately, we present a range of processes, operating at distinct scales, that must be better constrained to improve our understanding of how hydrothermalism affects the ocean cycling of iron and carbon. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.

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Cavan, Emma L., Stephanie A. Henson, Anna Belcher, and Richard Sanders. "Role of zooplankton in determining the efficiency of the biological carbon pump." Biogeosciences 14, no. 1 (January 12, 2017): 177–86. http://dx.doi.org/10.5194/bg-14-177-2017.

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Abstract. The efficiency of the ocean's biological carbon pump (BCPeff – here the product of particle export and transfer efficiencies) plays a key role in the air–sea partitioning of CO2. Despite its importance in the global carbon cycle, the biological processes that control BCPeff are poorly known. We investigate the potential role that zooplankton play in the biological carbon pump using both in situ observations and model output. Observed and modelled estimates of fast, slow, and total sinking fluxes are presented from three oceanic sites: the Atlantic sector of the Southern Ocean, the temperate North Atlantic, and the equatorial Pacific oxygen minimum zone (OMZ). We find that observed particle export efficiency is inversely related to primary production likely due to zooplankton grazing, in direct contrast to the model estimates. The model and observations show strongest agreement in remineralization coefficients and BCPeff at the OMZ site where zooplankton processing of particles in the mesopelagic zone is thought to be low. As the model has limited representation of zooplankton-mediated remineralization processes, we suggest that these results point to the importance of zooplankton in setting BCPeff, including particle grazing and fragmentation, and the effect of diel vertical migration. We suggest that improving parameterizations of zooplankton processes may increase the fidelity of biogeochemical model estimates of the biological carbon pump. Future changes in climate such as the expansion of OMZs may decrease the role of zooplankton in the biological carbon pump globally, hence increasing its efficiency.

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Neuer, Susanne, Morten Iversen, and Gerhard Fischer. "The Ocean's Biological Carbon pump as part of the global Carbon Cycle." Limnology and Oceanography e-Lectures 4, no. 4 (2014): 1–51. http://dx.doi.org/10.4319/lol.2014.sneuer.miversen.gfischer.9.

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14

Galbraith, Eric D., and Luke C. Skinner. "The Biological Pump During the Last Glacial Maximum." Annual Review of Marine Science 12, no. 1 (January 3, 2020): 559–86. http://dx.doi.org/10.1146/annurev-marine-010419-010906.

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Much of the global cooling during ice ages arose from changes in ocean carbon storage that lowered atmospheric CO2. A slew of mechanisms, both physical and biological, have been proposed as key drivers of these changes. Here we discuss the current understanding of these mechanisms with a focus on how they altered the theoretically defined soft-tissue and biological disequilibrium carbon storage at the peak of the last ice age. Observations and models indicate a role for Antarctic sea ice through its influence on ocean circulation patterns, but other mechanisms, including changes in biological processes, must have been important as well, and may have been coordinated through links with global air temperature. Further research is required to better quantify the contributions of the various mechanisms, and there remains great potential to use the Last Glacial Maximum and the ensuing global warming as natural experiments from which to learn about climate-driven changes in the marine ecosystem.

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Buesseler, Ken O., Philip W. Boyd, Erin E. Black, and David A. Siegel. "Metrics that matter for assessing the ocean biological carbon pump." Proceedings of the National Academy of Sciences 117, no. 18 (April 6, 2020): 9679–87. http://dx.doi.org/10.1073/pnas.1918114117.

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The biological carbon pump (BCP) comprises wide-ranging processes that set carbon supply, consumption, and storage in the oceans’ interior. It is becoming increasingly evident that small changes in the efficiency of the BCP can significantly alter ocean carbon sequestration and, thus, atmospheric CO2 and climate, as well as the functioning of midwater ecosystems. Earth system models, including those used by the United Nation’s Intergovernmental Panel on Climate Change, most often assess POC (particulate organic carbon) flux into the ocean interior at a fixed reference depth. The extrapolation of these fluxes to other depths, which defines the BCP efficiencies, is often executed using an idealized and empirically based flux-vs.-depth relationship, often referred to as the “Martin curve.” We use a new compilation of POC fluxes in the upper ocean to reveal very different patterns in BCP efficiencies depending upon whether the fluxes are assessed at a fixed reference depth or relative to the depth of the sunlit euphotic zone (Ez). We find that the fixed-depth approach underestimates BCP efficiencies when the Ez is shallow, and vice versa. This adjustment alters regional assessments of BCP efficiencies as well as global carbon budgets and the interpretation of prior BCP studies. With several international studies recently underway to study the ocean BCP, there are new and unique opportunities to improve our understanding of the mechanistic controls on BCP efficiencies. However, we will only be able to compare results between studies if we use a common set of Ez-based metrics.

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Lebrato, Mario, and Daniel O. B. Jones. "Expanding the oceanic carbon cycle: Jellyfish biomass in the biological pump." Biochemist 33, no. 3 (June 1, 2011): 35–39. http://dx.doi.org/10.1042/bio03303035.

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With atmospheric CO2 concentrations increasing, it is vital to improve our understanding of the processes that sequester carbon, the most important being the biological pump of the world's oceans. Jellyfish might not spring to mind as major players in the global carbon cycle but the evidence of large jelly-falls on the world's deep seabeds suggests that gelatinous zooplankton have a greater role in the biological pump than we thought previously. Jellyfish blooms may be increasing and dead jellyfish may offer a rapidly accessible food source as they sink. We have developed a model to explore the remineralization of gelatinous carcasses as they sink, which is allowing us to predict the effects of jelly-falls on carbon transfer around the world.

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HONJO, SUSUMU. "Particle export and the biological pump in the Southern Ocean." Antarctic Science 16, no. 4 (November 30, 2004): 501–16. http://dx.doi.org/10.1017/s0954102004002287.

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The organic carbon particle export to the interior layers in the Southern Ocean in the New Zealand–Tasmania Sector was approximately 170 mmolC m−2 yr−1. The export of particulate inorganic carbon in CaCO3 was 110 mmolC m−2 yr−1 and was contributed mostly by pteropods shells in the Antarctic Zones. The Si flux from biogenic opal at the sub-Antarctic Zone was 67 mmolSi m−2 yr−1 and rapidly increased to the south up to nearly 1 molSi m−2 yr−1 in the Antarctic Zone. The Antarctic Polar Front clearly demarcated the area where the biological pump was driven by CaCO3 to the north and biogenic SiO2 particle export to the south. Summer stratification caused by the sub-zero winter water layer in the Seasonal Ice Zone (SIZ) curtails the zooplankton community and hinders the replenishment of Fe. This hypothesis explains the large organic carbon export with large f- and export ratios at the SIZ and extremely large opal production at the Antarctic Circumpolar Zone. Estimated regeneration rate of CO2 from the export production and settling particulate fluxes of organic carbon in the water column between 100 m to 1 km was about 13 mmolC m−2 d−1 in the Antarctic Zone and Polar Frontal Zone.

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Zhang, Chuanlun, Hongyue Dang, Farooq Azam, Ronald Benner, Louis Legendre, Uta Passow, Luca Polimene, Carol Robinson, Curtis A. Suttle, and Nianzhi Jiao. "Evolving paradigms in biological carbon cycling in the ocean." National Science Review 5, no. 4 (July 1, 2018): 481–99. http://dx.doi.org/10.1093/nsr/nwy074.

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ABSTRACT Carbon is a keystone element in global biogeochemical cycles. It plays a fundamental role in biotic and abiotic processes in the ocean, which intertwine to mediate the chemistry and redox status of carbon in the ocean and the atmosphere. The interactions between abiotic and biogenic carbon (e.g. CO2, CaCO3, organic matter) in the ocean are complex, and there is a half-century-old enigma about the existence of a huge reservoir of recalcitrant dissolved organic carbon (RDOC) that equates to the magnitude of the pool of atmospheric CO2. The concepts of the biological carbon pump (BCP) and the microbial loop (ML) shaped our understanding of the marine carbon cycle. The more recent concept of the microbial carbon pump (MCP), which is closely connected to those of the BCP and the ML, explicitly considers the significance of the ocean's RDOC reservoir and provides a mechanistic framework for the exploration of its formation and persistence. Understanding of the MCP has benefited from advanced ‘omics’ and novel research in biological oceanography and microbial biogeochemistry. The need to predict the ocean's response to climate change makes an integrative understanding of the BCP, ML and MCP a high priority. In this review, we summarize and discuss progress since the proposal of the MCP in 2010 and formulate research questions for the future.

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Pan, Adam, Babak Pourziaei, and Huaxiong Huang. "Effect of Ocean Iron Fertilization on the Phytoplankton Biological Carbon Pump." Advances in Applied Mathematics and Mechanics 3, no. 1 (February 2011): 52–64. http://dx.doi.org/10.4208/aamm.10-m1023.

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AbstractIt has been proposed that photosynthetic plankton can be used as a biological carbon pump tp absorb and sequester carbon dioxide in the ocean. In this paper, plankton population dynamics are simulated in a single stratified water column to predict carbon dioxide sequestering due to surface iron fertilization in deep ocean. Using a predator-prey model and realistic parameter values, iron fertilization was found to only cause temporary blooms up to 5 months in duration, and relatively small increases in adsorption of atmospheric CO2.

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Mitra, A., K. J. Flynn, J. M. Burkholder, T. Berge, A. Calbet, J. A. Raven, E. Granéli, et al. "The role of mixotrophic protists in the biological carbon pump." Biogeosciences 11, no. 4 (February 20, 2014): 995–1005. http://dx.doi.org/10.5194/bg-11-995-2014.

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Abstract. The traditional view of the planktonic food web describes consumption of inorganic nutrients by photoautotrophic phytoplankton, which in turn supports zooplankton and ultimately higher trophic levels. Pathways centred on bacteria provide mechanisms for nutrient recycling. This structure lies at the foundation of most models used to explore biogeochemical cycling, functioning of the biological pump, and the impact of climate change on these processes. We suggest an alternative new paradigm, which sees the bulk of the base of this food web supported by protist plankton communities that are mixotrophic – combining phototrophy and phagotrophy within a single cell. The photoautotrophic eukaryotic plankton and their heterotrophic microzooplankton grazers dominate only during the developmental phases of ecosystems (e.g. spring bloom in temperate systems). With their flexible nutrition, mixotrophic protists dominate in more-mature systems (e.g. temperate summer, established eutrophic systems and oligotrophic systems); the more-stable water columns suggested under climate change may also be expected to favour these mixotrophs. We explore how such a predominantly mixotrophic structure affects microbial trophic dynamics and the biological pump. The mixotroph-dominated structure differs fundamentally in its flow of energy and nutrients, with a shortened and potentially more efficient chain from nutrient regeneration to primary production. Furthermore, mixotrophy enables a direct conduit for the support of primary production from bacterial production. We show how the exclusion of an explicit mixotrophic component in studies of the pelagic microbial communities leads to a failure to capture the true dynamics of the carbon flow. In order to prevent a misinterpretation of the full implications of climate change upon biogeochemical cycling and the functioning of the biological pump, we recommend inclusion of multi-nutrient mixotroph models within ecosystem studies.

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Mitra, A., K. J. Flynn, J. M. Burkholder, T. Berge, A. Calbet, J. A. Raven, E. Granéli, et al. "The role of mixotrophic protists in the biological carbon pump." Biogeosciences Discussions 10, no. 8 (August 15, 2013): 13535–62. http://dx.doi.org/10.5194/bgd-10-13535-2013.

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Abstract. The traditional view of the planktonic foodweb describes consumption of inorganic nutrients by photo-autotrophic phytoplankton, which in turn supports zooplankton and ultimately higher trophic levels. Pathways centred on bacteria provide mechanisms for nutrient recycling. This structure lies at the foundation of most models used to explore biogeochemical cycling, functioning of the biological pump, and the impact of climate change on these processes. We suggest an alternative paradigm, which sees the bulk of the base of this foodweb supported by protist plankton (phytoplankton and microzooplankton) communities that are mixotrophic – combining phototrophy and phagotrophy within a~single cell. The photoautotrophic eukaryotic plankton and their heterotrophic microzooplankton grazers dominate only within immature environments (e.g., spring bloom in temperate systems). With their flexible nutrition, mixotrophic protists dominate in more mature systems (e.g., temperate summer, established eutrophic systems and oligotrophic systems); the more stable water columns suggested under climate change may also be expected to favour these mixotrophs. We explore how such a predominantly mixotrophic structure affects microbial trophic dynamics and the biological pump. The mixotroph dominated structure differs fundamentally in its flow of energy and nutrients, with a shortened and potentially more efficient chain from nutrient regeneration to primary production. Furthermore, mixotrophy enables a direct conduit for the support of primary production from bacterial production. We show how the exclusion of an explicit mixotrophic component in studies of the pelagic microbial communities leads to a failure to capture the true dynamics of the carbon flow. In order to prevent a misinterpretation of the full implications of climate change upon biogeochemical cycling and the functioning of the biological pump, we recommend inclusion of multi-nutrient mixotroph models within ecosystem studies.

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Resplandy, Laure, Marina Lévy, and Dennis J. McGillicuddy. "Effects of Eddy‐Driven Subduction on Ocean Biological Carbon Pump." Global Biogeochemical Cycles 33, no. 8 (August 2019): 1071–84. http://dx.doi.org/10.1029/2018gb006125.

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Tréguer, Paul, Chris Bowler, Brivaela Moriceau, Stephanie Dutkiewicz, Marion Gehlen, Olivier Aumont, Lucie Bittner, et al. "Influence of diatom diversity on the ocean biological carbon pump." Nature Geoscience 11, no. 1 (December 18, 2017): 27–37. http://dx.doi.org/10.1038/s41561-017-0028-x.

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Huang, Shih-Chieh J., Alexander B. Artyukhin, Nipun Misra, Julio A. Martinez, Pieter A. Stroeve, Costas P. Grigoropoulos, Jiann-Wen W. Ju, and Aleksandr Noy. "Carbon Nanotube Transistor Controlled by a Biological Ion Pump Gate." Nano Letters 10, no. 5 (May 12, 2010): 1812–16. http://dx.doi.org/10.1021/nl100499x.

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Morée, Anne L., Jörg Schwinger, Ulysses S. Ninnemann, Aurich Jeltsch-Thömmes, Ingo Bethke, and Christoph Heinze. "Evaluating the biological pump efficiency of the Last Glacial Maximum ocean using δ13C." Climate of the Past 17, no. 2 (April 6, 2021): 753–74. http://dx.doi.org/10.5194/cp-17-753-2021.

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Abstract. Although both physical and biological marine changes are required to explain the 100 ppm lower atmospheric pCO2 of the Last Glacial Maximum (LGM, ∼21 ka) as compared to preindustrial (PI) times, their exact contributions are debated. Proxies of past marine carbon cycling (such as δ13C) document these changes and thus provide constraints for quantifying the drivers of long-term carbon cycle variability. This modeling study discusses the physical and biological changes in the ocean needed to simulate an LGM ocean in satisfactory agreement with proxy data, here focusing especially on δ13C. We prepared a PI and LGM equilibrium simulation using the ocean model NorESM-OC with full biogeochemistry (including the carbon isotopes δ13C and radiocarbon) and dynamic sea ice. The modeled LGM–PI differences are evaluated against a wide range of physical and biogeochemical proxy data and show agreement for key aspects of the physical ocean state within the data uncertainties. However, the lack of a simulated increase of regenerated nutrients for the LGM indicates that additional biogeochemical changes are required to simulate an LGM ocean in agreement with proxy data. In order to examine these changes, we explore the potential effects of different global mean biological pump efficiencies on the simulated marine biogeochemical tracer distributions. Through estimating which biological pump efficiency reduces LGM model–proxy biases the most, we estimate that the global mean biological pump efficiency increased from 38 % (PI) to up to 75 % (LGM). The drivers of such an increase in the biological pump efficiency may be both biological and related to circulation changes that are incompletely captured by our model – such as stronger isolation of Southern Source Water. Finally, even after considering a 75 % biological pump efficiency in the LGM ocean, a remaining model–proxy error in δ13C exists that is 0.07 ‰ larger than the 0.19 ‰ data uncertainty. This error indicates that additional changes in ocean dynamics are needed to simulate an LGM ocean in agreement with proxy data.

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Richardson, Tammi L. "Mechanisms and Pathways of Small-Phytoplankton Export from the Surface Ocean." Annual Review of Marine Science 11, no. 1 (January 3, 2019): 57–74. http://dx.doi.org/10.1146/annurev-marine-121916-063627.

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Carbon fixation by phytoplankton near the surface and the sinking of this particulate material to deeper waters are key components of the biological carbon pump. The efficiency of the biological pump is influenced by the size and taxonomic composition of the phytoplankton community. Large, heavily ballasted taxa such as diatoms sink quickly and thus efficiently remove fixed carbon from the upper ocean. Smaller, nonballasted species such as picoplanktonic cyanobacteria are usually thought to contribute little to export production. Research in the past decade, however, has shed new light on the potential importance of small phytoplankton to carbon export, especially in oligotrophic oceans, where small cells dominate primary productivity. Here, I examine the mechanisms and pathways through which small-phytoplankton carbon is exported from the surface ocean and the role of small phytoplankton in food webs of a variety of ocean ecosystems.

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Oschlies, A. "Impact of atmospheric and terrestrial CO2 feedbacks on fertilization-induced marine carbon uptake." Biogeosciences Discussions 6, no. 2 (April 23, 2009): 4493–525. http://dx.doi.org/10.5194/bgd-6-4493-2009.

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Abstract. The sensitivity of oceanic CO2 uptake to alterations in the marine biological carbon pump, such as brought about by natural or purposeful ocean fertilization, has repeatedly been investigated by studies employing numerical biogeochemical ocean models. It is shown here that the results of such ocean-centered studies are very sensitive to the assumption made about the response of the carbon reservoirs on the atmospheric side of the sea surface. Assumptions made include prescribed atmospheric pCO2, an interactive atmospheric CO2 pool exchanging carbon with the ocean but not with the terrestrial biosphere, and an interactive atmosphere that exchanges carbon with both oceanic and terrestrial carbon pools. The impact of these assumptions on simulated annual to millennial oceanic carbon uptake is investigated for a hypothetical increase in the C:N ratio of the biological pump and for an idealized enhancement of phytoplankton growth. Compared to simulations with interactive atmosphere, using prescribed atmospheric pCO2 overestimates the sensitivity of the oceanic CO2 uptake to changes in the biological pump, by about 2%, 25%, 100%, and >500% on annual, decadal, centennial, and millennial timescales, respectively. Adding an interactive terrestrial carbon pool to the atmosphere-ocean model system has a small effect on annual timescales, but increases the simulated fertilization-induced oceanic carbon uptake by about 4%, 50%, and 100% on decadal, centennial, and millennial timescales, respectively. On longer than decadal timescales, a substantial fraction of oceanic carbon uptake induced by natural or purposeful ocean fertilization may not come from the atmosphere but from the terrestrial biosphere.

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Khatiwala, S., A. Schmittner, and J. Muglia. "Air-sea disequilibrium enhances ocean carbon storage during glacial periods." Science Advances 5, no. 6 (June 2019): eaaw4981. http://dx.doi.org/10.1126/sciadv.aaw4981.

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The prevailing hypothesis for lower atmospheric carbon dioxide (CO2) concentrations during glacial periods is an increased efficiency of the ocean’s biological pump. However, tests of this and other hypotheses have been hampered by the difficulty to accurately quantify ocean carbon components. Here, we use an observationally constrained earth system model to precisely quantify these components and the role that different processes play in simulated glacial-interglacial CO2 variations. We find that air-sea disequilibrium greatly amplifies the effects of cooler temperatures and iron fertilization on glacial ocean carbon storage even as the efficiency of the soft-tissue biological pump decreases. These two processes, which have previously been regarded as minor, explain most of our simulated glacial CO2 drawdown, while ocean circulation and sea ice extent, hitherto considered dominant, emerge as relatively small contributors.

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Penta, W. Bryce, James Fox, and Kimberly H. Halsey. "Rapid photoacclimation during episodic deep mixing augments the biological carbon pump." Limnology and Oceanography 66, no. 5 (April 5, 2021): 1850–66. http://dx.doi.org/10.1002/lno.11728.

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Jin, Di, Porter Hoagland, and Ken O. Buesseler. "The value of scientific research on the ocean's biological carbon pump." Science of The Total Environment 749 (December 2020): 141357. http://dx.doi.org/10.1016/j.scitotenv.2020.141357.

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Neuer, Susanne, Robert Davenport, Tim Freudenthal, Gerold Wefer, Octavio Llinás, Maria-Jose Rueda, Deborah K. Steinberg, and David M. Karl. "Differences in the biological carbon pump at three subtropical ocean sites." Geophysical Research Letters 29, no. 18 (September 2002): 32–1. http://dx.doi.org/10.1029/2002gl015393.

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Oschlies, A. "Impact of atmospheric and terrestrial CO2 feedbacks on fertilization-induced marine carbon uptake." Biogeosciences 6, no. 8 (August 11, 2009): 1603–13. http://dx.doi.org/10.5194/bg-6-1603-2009.

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Abstract. The sensitivity of oceanic CO2 uptake to alterations in the marine biological carbon pump, such as brought about by natural or purposeful ocean fertilization, has repeatedly been investigated by studies employing numerical biogeochemical ocean models. It is shown here that the results of such ocean-centered studies are very sensitive to the assumption made about the response of the carbon reservoirs on the atmospheric side of the sea surface. Assumptions made include prescribed atmospheric pCO2, an interactive atmospheric CO2 pool exchanging carbon with the ocean but not with the terrestrial biosphere, and an interactive atmosphere that exchanges carbon with both oceanic and terrestrial carbon pools. The impact of these assumptions on simulated annual to millennial oceanic carbon uptake is investigated for a hypothetical increase in the C:N ratio of the biological pump and for an idealized enhancement of phytoplankton growth. Compared to simulations with interactive atmosphere, using prescribed atmospheric pCO2 overestimates the sensitivity of the oceanic CO2 uptake to changes in the biological pump, by about 2%, 25%, 100%, and >500% on annual, decadal, centennial, and millennial timescales, respectively. The smaller efficiency of the oceanic carbon uptake under an interactive atmosphere is due to the back flux of CO2 that occurs when atmospheric CO2 is reduced. Adding an interactive terrestrial carbon pool to the atmosphere-ocean model system has a small effect on annual timescales, but increases the simulated fertilization-induced oceanic carbon uptake by about 4%, 50%, and 100% on decadal, centennial, and millennial timescales, respectively, for pCO2 sensitivities of the terrestrial carbon storage in the middle range of the C4MIP models (Friedlingstein et al., 2006). For such sensitivities, a substantial fraction of oceanic carbon uptake induced by natural or purposeful ocean fertilization originates, on timescales longer than decades, not from the atmosphere but from the terrestrial biosphere.

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Bauska, Thomas K., Daniel Baggenstos, Edward J. Brook, Alan C. Mix, Shaun A. Marcott, Vasilii V. Petrenko, Hinrich Schaefer, Jeffrey P. Severinghaus, and James E. Lee. "Carbon isotopes characterize rapid changes in atmospheric carbon dioxide during the last deglaciation." Proceedings of the National Academy of Sciences 113, no. 13 (March 14, 2016): 3465–70. http://dx.doi.org/10.1073/pnas.1513868113.

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An understanding of the mechanisms that control CO2 change during glacial–interglacial cycles remains elusive. Here we help to constrain changing sources with a high-precision, high-resolution deglacial record of the stable isotopic composition of carbon in CO2 (δ13C-CO2) in air extracted from ice samples from Taylor Glacier, Antarctica. During the initial rise in atmospheric CO2 from 17.6 to 15.5 ka, these data demarcate a decrease in δ13C-CO2, likely due to a weakened oceanic biological pump. From 15.5 to 11.5 ka, the continued atmospheric CO2 rise of 40 ppm is associated with small changes in δ13C-CO2, consistent with a nearly equal contribution from a further weakening of the biological pump and rising ocean temperature. These two trends, related to marine sources, are punctuated at 16.3 and 12.9 ka with abrupt, century-scale perturbations in δ13C-CO2 that suggest rapid oxidation of organic land carbon or enhanced air–sea gas exchange in the Southern Ocean. Additional century-scale increases in atmospheric CO2 coincident with increases in atmospheric CH4 and Northern Hemisphere temperature at the onset of the Bølling (14.6–14.3 ka) and Holocene (11.6–11.4 ka) intervals are associated with small changes in δ13C-CO2, suggesting a combination of sources that included rising surface ocean temperature.

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Skinner, L. C. "Glacial – interglacial atmospheric CO2 change: a possible "standing volume" effect on deep-ocean carbon sequestration." Climate of the Past Discussions 5, no. 3 (May 4, 2009): 1259–96. http://dx.doi.org/10.5194/cpd-5-1259-2009.

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Abstract. So far, the exploration of possible mechanisms for glacial atmospheric CO2 draw-down and marine carbon sequestration has focussed almost exclusively on dynamic or kinetic processes (i.e. variable mixing-, equilibration- or export rates). Here an attempt is made to underline instead the possible importance of changes in the standing volumes of intra-oceanic carbon reservoirs (i.e. different water-masses) in setting the total marine carbon inventory. By way of illustration, a simple mechanism is proposed for enhancing the carbon storage capacity of the deep sea, which operates via an increase in the volume of relatively carbon-enriched AABW-like deep-water filling the ocean basins. Given the hypsometry of the ocean floor and an active biological pump, the water-mass that fills more than the bottom 3 km of the ocean will essentially determine the carbon content of the marine reservoir. A set of simple box-model experiments confirm the expectation that a deep sea dominated by AABW-like deep-water holds more CO2, prior to any additional changes in ocean overturning rate, biological export or ocean-atmosphere exchange. The magnitude of this "standing volume effect" might be as large as the contributions that have been attributed to carbonate compensation, the thermodynamic solubility pump or the biological pump for example. If incorporated into the list of factors that have contributed to marine carbon sequestration during past glaciations, this standing volume mechanism may help to reduce the amount of glacial – interglacial CO2 change that remains to be explained by other mechanisms that are difficult to assess in the geological archive, such as reduced mass transport or mixing rates in particular. This in turn could help narrow the search for forcing conditions capable of pushing the global carbon cycle between glacial and interglacial modes.

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Firdaus, Mochamad Ramdhan, and Lady Ayu Sri Wijayanti. "FITOPLANKTON DAN SIKLUS KARBON GLOBAL." OSEANA 44, no. 2 (December 21, 2019): 35–48. http://dx.doi.org/10.14203/oseana.2019.vol.44no.2.39.

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PHYTOPLANKTON AND GLOBAL CARBON CYCLE. Scientists around the world believe that phytoplankton, although microscopic, have a large role in the global carbon cycle. Various research results show that the net primary productivity of all phytoplankton in the sea is almost as large as the net primary productivity of all plants on land. Phytoplankton through the process of photosynthesis absorbs 40-50 PgC / year from the atmosphere. Also, phytoplankton is known to be responsible for transporting carbon from the atmosphere to the seafloor through the carbon biological pump mechanism. Phytoplankton from the coccolithophores group is known to play a role in the sequestration of carbon on the seabed through the carbonate pump mechanism. The mechanism is capable of sequestering carbon for thousands of years on the seabed in the form of sedimentary rocks (limestone).

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Maia, N. L., M. L. Diniz, J. M. A. M. Gurgel, R. R. Gondim, M. Carvalho, and M. R. Luiz. "ENERGY STUDY OF A HEAT PUMP USED FOR AIR ( HEATING AND DEHUMIDIFICATION." Revista de Engenharia Térmica 14, no. 2 (December 31, 2015): 12. http://dx.doi.org/10.5380/reterm.v14i2.62126.

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Heat pump assisted dryers can realize considerable savings of primary energy as compared with conventionally-heated air drying. This manuscript analyzes the design and construction aspects of a heat pump assisted dryer for biological products. The performance of the heat pump is investigated through an energy analysis, carried out under operating conditions of practical interest. The system is operated using R22 and is also evaluated with respect to the coefficient of performance (COP). Although the current trend is to invest in low-energy, low-carbon technologies, heat pump assisted dryers remain underexplored in the industrial sector due to its more complex operation.

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Le Moigne, F. A. C., S. A. Henson, R. J. Sanders, and E. Madsen. "Global database of surface ocean particulate organic carbon export fluxes diagnosed from the 234Th technique." Earth System Science Data 5, no. 2 (August 12, 2013): 295–304. http://dx.doi.org/10.5194/essd-5-295-2013.

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Abstract. The oceanic biological carbon pump is an important factor in the global carbon cycle. Organic carbon is exported from the surface ocean mainly in the form of settling particles derived from plankton production in the upper layers of the ocean. The large variability in current estimates of the global strength of the biological carbon pump emphasises that our knowledge of a major planetary carbon flux remains poorly constrained. We present a database of 723 estimates of organic carbon export from the surface ocean derived from the 234Th technique. The dataset is archived on the data repository PANGEA® (www.pangea.de) under doi:10.1594/PANGAEA.809717. Data were collected from tables in papers published between 1985 and early 2013. We also present sampling dates, publication dates and sampling areas. Most of the open ocean provinces are represented by multiple measurements. However, the western Pacific, the Atlantic Arctic, South Pacific and the southern Indian Ocean are not well represented. There is a variety of integration depths ranging from surface to 300 m. Globally the fluxes ranged from 0 to 1500 mg C m−2 d−1.

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Le Moigne, F. A. C., S. A. Henson, R. J. Sanders, and E. Madsen. "Global database of surface ocean particulate organic carbon export fluxes diagnosed from the 234Th technique." Earth System Science Data Discussions 6, no. 1 (May 27, 2013): 163–87. http://dx.doi.org/10.5194/essdd-6-163-2013.

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Abstract. The oceanic biological carbon pump is an important factor in the global carbon cycle. Organic carbon is exported from the surface ocean mainly in the form of settling particles derived from plankton production in the upper layers of the ocean. The large variability in current estimates of the global strength of the biological carbon pump emphasises that our knowledge of a major planetary carbon flux remains poorly constrained. We present a database of 723 estimates of organic carbon export from the surface ocean derived from the 234Th technique. The dataset is archived on the data repository PANGEA® (www.pangea.de) under doi:10.1594/PANGAEA.809717. Data were collected from tables in papers published between 1985 and early 2013 only. We also present sampling dates, publication dates and sampling areas. Most of the open ocean provinces are represented by several measurements. However, the Western Pacific, the Atlantic Arctic, South Pacific and the South Indian Ocean are not well represented. There is a variety of integration depths ranging from surface to 220 m. Globally the fluxes ranged from 0 to 1500 mg of C m−2 d−1.

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Kim, Ji-Eun, Thomas Westerhold, Laia Alegret, Anna Joy Drury, Ursula Röhl, and Elizabeth M. Griffith. "Precessional pacing of tropical ocean carbon export during the Late Cretaceous." Climate of the Past 18, no. 12 (December 16, 2022): 2631–41. http://dx.doi.org/10.5194/cp-18-2631-2022.

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Abstract. The marine biological carbon pump, which exports organic carbon out of the surface ocean, plays an essential role in sequestering carbon from the atmosphere, thus impacting climate and affecting marine ecosystems. Orbital variations in solar insolation modulate these processes, but their influence on the tropical Pacific during the Late Cretaceous is unknown. Here we present a high-resolution composite record of elemental barium from deep-sea sediments as a proxy for organic carbon export out of the surface oceans (i.e., export production) from Shatsky Rise in the tropical Pacific. Variations in export production in the Pacific during the Maastrichtian, from 71.5 to 66 million years ago, were dominated by precession and less so by eccentricity modulation or obliquity, confirming that tropical surface-ocean carbon dynamics were influenced by seasonal insolation in the tropics during this greenhouse period. We suggest that precession paced primary production in the tropical Pacific and recycling in the euphotic zone by changing water column stratification, upwelling intensity, and continental nutrient fluxes. Benthic foraminiferal accumulation rates covaried with export production, providing evidence for bentho-pelagic coupling of the marine biological carbon pump across these high-frequency changes in a cool greenhouse planet.

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Henson, Stephanie A., Richard Sanders, Esben Madsen, Paul J. Morris, Frédéric Le Moigne, and Graham D. Quartly. "A reduced estimate of the strength of the ocean's biological carbon pump." Geophysical Research Letters 38, no. 4 (February 2011): n/a. http://dx.doi.org/10.1029/2011gl046735.

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Ryazantsev, Sergey N. "Use Tungsten Shadowing to Study Biological Macromolecules." Microscopy and Microanalysis 7, S2 (August 2001): 1206–7. http://dx.doi.org/10.1017/s1431927600032104.

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Shadowing is widely used for biological macromolecules and their complexes structure determination . It has been shown that tungsten shadowing produces fine granularity and good structural detail resolution. We have developed a working prototype of an electron beam evaporator (“electron gun“) based on the principle described by V. Vasiliev. The electron gun has characteristics that allow us to deposit high quality films of carbon or even pure tungsten. in addition we have constructed a prototype sample handling apparatus for freeze drying and shadowing. The prototype allows tilting of +/- 90° in 2° increments, rotation (if desired) at 6 rpm, controlled heating at a rate of 1-2° per min, and cooling using a liquid nitrogen trap attached to the device. The system is vacuumed by 480 1/sec maglev turbomolecular pump with scroll pump at the first stage. It produces oil-free vacuum in 2-5*10-7 torr range, which we believe, is sufficient for good quality shadowing.

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Jiao, Nianzhi, and Qiang Zheng. "The Microbial Carbon Pump: from Genes to Ecosystems." Applied and Environmental Microbiology 77, no. 21 (August 26, 2011): 7439–44. http://dx.doi.org/10.1128/aem.05640-11.

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ABSTRACTThe majority of marine dissolved organic carbon (DOC) is resistant to biological degradation and thus can remain in the water column for thousands of years, constituting carbon sequestration in the ocean. To date the origin of such recalcitrant DOC (RDOC) is unclear. A recently proposed conceptual framework, the microbial carbon pump (MCP), emphasizes the microbial transformation of organic carbon from labile to recalcitrant states. The MCP is concerned with both microbial uptakes and outputs of DOC compounds, covering a wide range from gene to ecosystem levels. In this minireview, the ATP binding cassette (ABC) transporter is used as an example for the microbial processing of DOC at the genetic level. The compositions of the ABC transporter genes of the two major marine bacterial cladesRoseobacterand SAR11 demonstrate that they have distinct patterns in DOC utilization:Roseobacterstrains have the advantage of taking up carbohydrate DOC, while SAR11 bacteria prefer nitrogen-containing DOC. At the ecosystem level, bacterially derived RDOC based ond-amino acid biomarkers is reported to be responsible for about a quarter of the total marine RDOC pool. Under future global warming scenarios, partitioning of primary production into DOC could be enhanced, and thus the MCP could play an even more important role in carbon sequestration by the ocean. Joint efforts to study the MCP from multiple disciplines are required to obtain a better understanding of ocean carbon cycle and its coupling with global change.

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Tanet, Lisa, Séverine Martini, Laurie Casalot, and Christian Tamburini. "Reviews and syntheses: Bacterial bioluminescence – ecology and impact in the biological carbon pump." Biogeosciences 17, no. 14 (July 17, 2020): 3757–78. http://dx.doi.org/10.5194/bg-17-3757-2020.

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Abstract. Around 30 species of marine bacteria can emit light, a critical characteristic in the oceanic environment is mostly deprived of sunlight. In this article, we first review current knowledge on bioluminescent bacteria symbiosis in light organs. Then, focusing on gut-associated bacteria, we highlight that recent works, based on omics methods, confirm previous claims about the prominence of bioluminescent bacterial species in fish guts. Such host–symbiont relationships are relatively well-established and represent important knowledge in the bioluminescence field. However, the consequences of bioluminescent bacteria continuously released from light organs and through the digestive tracts to the seawater have been barely taken into account at the ecological and biogeochemical level. For too long neglected, we propose considering the role of bioluminescent bacteria and reconsidering the biological carbon pump, taking into account the bioluminescence effect (“bioluminescence shunt hypothesis”). Indeed, it has been shown that marine snow and fecal pellets are often luminous due to microbial colonization, which makes them a visual target. These luminous particles seem preferentially consumed by organisms of higher trophic levels in comparison to nonluminous ones. As a consequence, the sinking rate of consumed particles could be either increased (due to repackaging) or reduced (due to sloppy feeding or coprophagy/coprorhexy), which can imply a major impact on global biological carbon fluxes. Finally, we propose a strategy, at a worldwide scale, relying on recently developed instrumentation and methodological tools to quantify the impact of bioluminescent bacteria in the biological carbon pump.

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Yamamoto, Akitomo, Ayako Abe-Ouchi, Rumi Ohgaito, Akinori Ito, and Akira Oka. "Glacial CO2 decrease and deep-water deoxygenation by iron fertilization from glaciogenic dust." Climate of the Past 15, no. 3 (June 4, 2019): 981–96. http://dx.doi.org/10.5194/cp-15-981-2019.

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Abstract. Increased accumulation of respired carbon in the deep ocean associated with enhanced efficiency of the biological carbon pump is thought to be a key mechanism of glacial CO2 drawdown. Despite greater oxygen solubility due to seawater cooling, recent quantitative and qualitative proxy data show glacial deep-water deoxygenation, reflecting increased respired carbon accumulation. However, the mechanisms of deep-water deoxygenation and contribution from the biological pump to glacial CO2 drawdown have remained unclear. In this study, we report the significance of iron fertilization from glaciogenic dust in glacial CO2 decrease and deep-water deoxygenation using our numerical simulation, which successfully reproduces the magnitude and large-scale pattern of the observed oxygen changes from the present to the Last Glacial Maximum. Sensitivity experiments show that physical changes contribute to only one-half of all glacial deep deoxygenation, whereas the other one-half is driven by iron fertilization and an increase in the whole ocean nutrient inventory. We find that iron input from glaciogenic dust with higher iron solubility is the most significant factor in enhancing the biological pump and deep-water deoxygenation. Glacial deep-water deoxygenation expands the hypoxic waters in the deep Pacific and Indian oceans. The simulated global volume of hypoxic waters is nearly double the present value, suggesting that glacial deep water was a more severe environment for benthic animals than that of the modern oceans. Our model underestimates the deoxygenation in the deep Southern Ocean because of enhanced ventilation. The model–proxy comparison of oxygen change suggests that a stratified Southern Ocean is required for reproducing the oxygen decrease in the deep Southern Ocean. Iron fertilization and a global nutrient increase contribute to a decrease in glacial CO2 of more than 30 ppm, which is supported by the model–proxy agreement of oxygen change. Our findings confirm the significance of the biological pump in glacial CO2 drawdown and deoxygenation.

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Pasquier, Benoît, Mark Holzer, Matthew A. Chamberlain, Richard J. Matear, Nathaniel L. Bindoff, and François W. Primeau. "Optimal parameters for the ocean's nutrient, carbon, and oxygen cycles compensate for circulation biases but replumb the biological pump." Biogeosciences 20, no. 14 (July 26, 2023): 2985–3009. http://dx.doi.org/10.5194/bg-20-2985-2023.

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Abstract. Accurate predictive modeling of the ocean's global carbon and oxygen cycles is challenging because of uncertainties in both biogeochemistry and ocean circulation. Advances over the last decade have made parameter optimization feasible, allowing models to better match observed biogeochemical fields. However, does fitting a biogeochemical model to observed tracers using a circulation with known biases robustly capture the inner workings of the biological pump? Here we embed a mechanistic model of the ocean's coupled nutrient, carbon, and oxygen cycles into two circulations for the current climate. To assess the effects of biases, one circulation (ACCESS-M) is derived from a climate model and the other from data assimilation of observations (OCIM2). We find that parameter optimization compensates for circulation biases at the expense of altering how the biological pump operates. Tracer observations constrain pump strength and regenerated inventories for both circulations, but ACCESS-M export production optimizes to twice that of OCIM2 to compensate for ACCESS-M having lower sequestration efficiencies driven by less efficient particle transfer and shorter residence times. Idealized simulations forcing complete Southern Ocean nutrient utilization show that the response of the optimized system is sensitive to the embedding circulation. In ACCESS-M, Southern Ocean nutrient and dissolved inorganic carbon (DIC) trapping is partially short circuited by unrealistically deep mixed layers. For both circulations, intense Southern Ocean production deoxygenates Southern-Ocean-sourced deep waters, muting the imprint of circulation biases on oxygen. Our findings highlight that the biological pump's plumbing needs careful assessment to predict the biogeochemical response to ecological changes, even when optimally matching observations.

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Lade, Steven J., Jonathan F. Donges, Ingo Fetzer, John M. Anderies, Christian Beer, Sarah E. Cornell, Thomas Gasser, et al. "Analytically tractable climate–carbon cycle feedbacks under 21st century anthropogenic forcing." Earth System Dynamics 9, no. 2 (May 17, 2018): 507–23. http://dx.doi.org/10.5194/esd-9-507-2018.

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Abstract. Changes to climate–carbon cycle feedbacks may significantly affect the Earth system's response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth system models. Here, we construct a stylised global climate–carbon cycle model, test its output against comprehensive Earth system models, and investigate the strengths of its climate–carbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon cycle feedbacks and the operation of the carbon cycle. Specific results include that different feedback formalisms measure fundamentally the same climate–carbon cycle processes; temperature dependence of the solubility pump, biological pump, and CO2 solubility all contribute approximately equally to the ocean climate–carbon feedback; and concentration–carbon feedbacks may be more sensitive to future climate change than climate–carbon feedbacks. Simple models such as that developed here also provide workbenches for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the planetary boundaries, that are currently too uncertain to be included in comprehensive Earth system models.

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Stukel, Michael R., Moira Décima, and Michael R. Landry. "Quantifying biological carbon pump pathways with a data-constrained mechanistic model ensemble approach." Biogeosciences 19, no. 15 (August 5, 2022): 3595–624. http://dx.doi.org/10.5194/bg-19-3595-2022.

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Abstract. The ability to constrain the mechanisms that transport organic carbon into the deep ocean is complicated by the multiple physical, chemical, and ecological processes that intersect to create, transform, and transport particles in the ocean. In this paper we develop and parameterize a data-assimilative model of the multiple pathways of the biological carbon pump (NEMUROBCP). The mechanistic model is designed to represent sinking particle flux, active transport by vertically migrating zooplankton, and passive transport by subduction and vertical mixing, while also explicitly representing multiple biological and chemical properties measured directly in the field (including nutrients, phytoplankton and zooplankton taxa, carbon dioxide and oxygen, nitrogen isotopes, and 234Thorium). Using 30 different data types (including standing stock and rate measurements related to nutrients, phytoplankton, zooplankton, and non-living organic matter) from Lagrangian experiments conducted on 11 cruises from four ocean regions, we conduct an objective statistical parameterization of the model and generate 1 million different potential parameter sets that are used for ensemble model simulations. The model simulates in situ parameters that were assimilated (net primary production and gravitational particle flux) and parameters that were withheld (234Thorium and nitrogen isotopes) with reasonable accuracy. Model results show that gravitational flux of sinking particles and vertical mixing of organic matter from the euphotic zone are more important biological pump pathways than active transport by vertically migrating zooplankton. However, these processes are regionally variable, with sinking particles most important in oligotrophic areas of the Gulf of Mexico and California Current, sinking particles and vertical mixing roughly equivalent in productive coastal upwelling regions and the subtropical front in the Southern Ocean, and active transport an important contributor in the eastern tropical Pacific. We further find that mortality at depth is an important component of active transport when mesozooplankton biomass is high, but it is negligible in regions with low mesozooplankton biomass. Our results also highlight the high degree of uncertainty, particularly amongst mesozooplankton functional groups, that is derived from uncertainty in model parameters. Indeed, variability in BCP pathways between simulations for a specific location using different parameter sets (all with approximately equal misfit relative to observations) is comparable to variability in BCP pathways between regions. We discuss the implications of these results for other data-assimilation approaches and for studies that rely on non-ensemble model outputs.

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Ma, Zhongwu, Ellen Gray, Ellen Thomas, Brandon Murphy, James Zachos, and Adina Paytan. "Carbon sequestration during the Palaeocene–Eocene Thermal Maximum by an efficient biological pump." Nature Geoscience 7, no. 5 (April 13, 2014): 382–88. http://dx.doi.org/10.1038/ngeo2139.

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Cavan, E. L., S. L. C. Giering, G. A. Wolff, M. Trimmer, and R. Sanders. "Alternative Particle Formation Pathways in the Eastern Tropical North Pacific's Biological Carbon Pump." Journal of Geophysical Research: Biogeosciences 123, no. 7 (July 2018): 2198–211. http://dx.doi.org/10.1029/2018jg004392.

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Jiao, N., Y. Zhang, K. Zhou, Q. Li, M. Dai, J. Liu, J. Guo, and B. Huang. "Why productive upwelling areas are often sources rather than sinks of CO2? – a comparative study on eddy upwellings in the South China Sea." Biogeosciences Discussions 10, no. 8 (August 13, 2013): 13399–426. http://dx.doi.org/10.5194/bgd-10-13399-2013.

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Abstract. Marine upwelling regions are known to be productive in carbon fixation and thus thought to be sinks of CO2, whereas many upwelling areas in the ocean are actually sources rather than sinks of CO2. To address this paradox, multiple biogeochemical parameters were investigated at two cyclonic-eddy-induced upwelling sites CE1 and CE2 in the western South China Sea. The results showed that upwelling can exert significant influences on biological activities in the euphotic zone and can either increase or decrease particulate organic carbon (POC) export flux depending on upwelling conditions such as the magnitude, timing, and duration of nutrient input and consequent microbial activities. At CE2 the increase of phytoplankton biomass caused by the upwelled nutrients resulted in increase of POC export flux compared to non-eddy reference sites, while at CE1 the microbial respiration of organic carbon stimulated by the upwelled nutrients significantly contributed to the attenuation of POC export flux, aggravating outgassing of CO2. These results suggest that on top of upwelled dissolved inorganic carbon release, microbial activities stimulated by upwelled nutrients and phytoplankton labile organic carbon can play a critical role for a marine upwelling area to be a source rather than a sink of CO2. Meanwhile, we point out that even though an upwelling region is outgassing, carbon sequestration still takes place through the POC-based biological pump as well as the refractory dissolved organic carbon (RDOC)-based microbial carbon pump.

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Journal articles on the topic 'Carbon biological pump'

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