Articles | Volume 10, issue 7
Research article 01 Jul 2013
Research article | 01 Jul 2013
Air–sea exchange of CO2 at a Northern California coastal site along the California Current upwelling system
H. Ikawa et al.
Related subject area
Biogeochemistry: Air - Sea ExchangeEukaryotic community composition in the sea surface microlayer across an east–west transect in the Mediterranean SeaEnhancement of the North Atlantic CO2 sink by Arctic WatersGlobal ocean dimethyl sulfide climatology estimated from observations and an artificial neural networkAtmospheric deposition of organic matter at a remote site in the central Mediterranean Sea: implications for the marine ecosystemUnderway seawater and atmospheric measurements of volatile organic compounds in the Southern OceanDimethylsulfide (DMS), marine biogenic aerosols and the ecophysiology of coral reefsSpatial variations in CO2 fluxes in the Saguenay Fjord (Quebec, Canada) and results of a water mixing modelGas exchange estimates in the Peruvian upwelling regime biased by multi-day near-surface stratificationInsights from year-long measurements of air–water CH4 and CO2 exchange in a coastal environmentOn the role of climate modes in modulating the air–sea CO2 fluxes in eastern boundary upwelling systemsReviews and syntheses: the GESAMP atmospheric iron deposition model intercomparison studyIncrease of dissolved inorganic carbon and decrease in pH in near-surface waters in the Mediterranean Sea during the past two decadesUtilizing the Drake Passage Time-series to understand variability and change in subpolar Southern Ocean pCO2Effect of wind speed on the size distribution of gel particles in the sea surface microlayer: insights from a wind–wave channel experimentThe seasonal cycle of pCO2 and CO2 fluxes in the Southern Ocean: diagnosing anomalies in CMIP5 Earth system modelsMarine phytoplankton stoichiometry mediates nonlinear interactions between nutrient supply, temperature, and atmospheric CO2Interannual drivers of the seasonal cycle of CO2 in the Southern OceanConstraints on global oceanic emissions of N2O from observations and modelsArctic Ocean CO2 uptake: an improved multiyear estimate of the air–sea CO2 flux incorporating chlorophyll a concentrationsUncertainty in the global oceanic CO2 uptake induced by wind forcing: quantification and spatial analysisPhytoplankton growth response to Asian dust addition in the northwest Pacific Ocean versus the Yellow SeaGlobal high-resolution monthly pCO2 climatology for the coastal ocean derived from neural network interpolationChanges in the partial pressure of carbon dioxide in the Mauritanian–Cap Vert upwelling region between 2005 and 2012Impact of ocean acidification on Arctic phytoplankton blooms and dimethyl sulfide concentration under simulated ice-free and under-ice conditionsCoral reef origins of atmospheric dimethylsulfide at Heron Island, southern Great Barrier Reef, AustraliaBioavailable atmospheric phosphorous supply to the global ocean: a 3-D global modeling studyCoastal-ocean uptake of anthropogenic carbonRole of zooplankton dynamics for Southern Ocean phytoplankton biomass and global biogeochemical cyclesSurfactant control of gas transfer velocity along an offshore coastal transect: results from a laboratory gas exchange tankClimate impacts on multidecadal pCO2 variability in the North Atlantic: 1948–2009The organic sea-surface microlayer in the upwelling region off the coast of Peru and potential implications for air–sea exchange processesThe impact of sedimentary alkalinity release on the water column CO2 system in the North SeaSoluble trace metals in aerosols over the tropical south-east Pacific offshore of PeruNew insights into fCO2 variability in the tropical eastern Pacific Ocean using SMOS SSSData-based estimates of the ocean carbon sink variability – first results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM)Quantifying importance and scaling effects of atmospheric deposition of inorganic fixed nitrogen for the eutrophic Black SeaHalocarbon emissions and sources in the equatorial Atlantic Cold TongueA strong CO2 sink enhanced by eutrophication in a tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil)Air–water fluxes and sources of carbon dioxide in the Delaware Estuary: spatial and seasonal variabilityModeling the global emission, transport and deposition of trace elements associated with mineral dustDynamics of air–sea CO2 fluxes in the northwestern European shelf based on voluntary observing ship and satellite observationsCarbon, oxygen and biological productivity in the Southern Ocean in and out the Kerguelen plume: CARIOCA drifter resultsRemote sensing the sea surface CO2 of the Baltic Sea using the SOMLO methodologyAtmospheric water-soluble organic nitrogen (WSON) over marine environments: a global perspectiveSensitivity of the air–sea CO2 exchange in the Baltic Sea and Danish inner waters to atmospheric short-term variabilityGlacial meltwater and primary production are drivers of strong CO2 uptake in fjord and coastal waters adjacent to the Greenland Ice SheetInorganic carbon dynamics of melt-pond-covered first-year sea ice in the Canadian ArcticSimulated anthropogenic CO2 storage and acidification of the Mediterranean SeaQuantifying environmental stress-induced emissions of algal isoprene and monoterpenes using laboratory measurementsThe effect of desiccation on the emission of volatile bromocarbons from two common temperate macroalgae
Birthe Zäncker, Michael Cunliffe, and Anja Engel
Biogeosciences, 18, 2107–2118,Short summary
Fungi are found in numerous marine environments. Our study found an increased importance of fungi in the Ionian Sea, where bacterial and phytoplankton counts were reduced, but organic matter was still available, suggesting fungi might benefit from the reduced competition from bacteria in low-nutrient, low-chlorophyll (LNLC) regions.
Jon Olafsson, Solveig R. Olafsdottir, Taro Takahashi, Magnus Danielsen, and Thorarinn S. Arnarson
Biogeosciences, 18, 1689–1701,Short summary
The Atlantic north of 50° N is an intense ocean sink area for atmospheric CO2. Observations in the vicinity of Iceland reveal a previously unrecognized Arctic contribution to the North Atlantic CO2 sink. Sustained CO2 influx to waters flowing from the Arctic Ocean is linked to their excess alkalinity derived from sources in the changing Arctic. The results relate to the following question: will the North Atlantic continue to absorb CO2 in the future as it has in the past?
Wei-Lei Wang, Guisheng Song, François Primeau, Eric S. Saltzman, Thomas G. Bell, and J. Keith Moore
Biogeosciences, 17, 5335–5354,Short summary
Dimethyl sulfide, a volatile compound produced as a byproduct of marine phytoplankton activity, can be emitted to the atmosphere via gas exchange. In the atmosphere, DMS is oxidized to cloud condensation nuclei, thus contributing to cloud formation. Therefore, oceanic DMS plays an important role in regulating the planet's climate by influencing the radiation budget. In this study, we use an artificial neural network model to update the global DMS climatology and estimate the sea-to-air flux.
Yuri Galletti, Silvia Becagli, Alcide di Sarra, Margherita Gonnelli, Elvira Pulido-Villena, Damiano M. Sferlazzo, Rita Traversi, Stefano Vestri, and Chiara Santinelli
Biogeosciences, 17, 3669–3684,Short summary
This paper reports the first data about atmospheric deposition of dissolved organic matter (DOM) on the island of Lampedusa. It also shows the implications for the surface marine layer by studying the impact of atmospheric organic carbon deposition in the marine ecosystem. It is a preliminary study, but it is pioneering and important for having new data that can be crucial in order to understand the impact of atmospheric deposition on the marine carbon cycle in a global climate change scenario.
Charel Wohl, Ian Brown, Vassilis Kitidis, Anna E. Jones, William T. Sturges, Philip D. Nightingale, and Mingxi Yang
Biogeosciences, 17, 2593–2619,Short summary
The oceans represent a poorly understood source of organic carbon to the atmosphere. In this paper, we present ship-based measurements of specific compounds in ambient air and seawater of the Southern Ocean. We present fluxes of these gases between air and sea at very high resolution. The data also contain evidence for day and night variations in some of these compounds. These measurements can be used to better understand the role of the Southern Ocean in the cycling of these compounds.
Rebecca L. Jackson, Albert J. Gabric, Roger Cropp, and Matthew T. Woodhouse
Biogeosciences, 17, 2181–2204,Short summary
Coral reefs are a strong source of atmospheric sulfur through stress-induced emissions of dimethylsulfide (DMS). This biogenic sulfur can influence aerosol and cloud properties and, consequently, the radiative balance over the ocean. DMS emissions may therefore help to mitigate coral physiological stress via increased low-level cloud cover and reduced sea surface temperature. The importance of DMS in coral physiology and climate is reviewed and the implications for coral bleaching are discussed.
Louise Delaigue, Helmuth Thomas, and Alfonso Mucci
Biogeosciences, 17, 547–566,Short summary
This paper reports on the first compilation and analysis of the surface water pCO2 distribution in the Saguenay Fjord, the southernmost subarctic fjord in the Northern Hemisphere, and thus fills a significant knowledge gap in current regional estimates of estuarine CO2 emissions.
Tim Fischer, Annette Kock, Damian L. Arévalo-Martínez, Marcus Dengler, Peter Brandt, and Hermann W. Bange
Biogeosciences, 16, 2307–2328,Short summary
We investigated air–sea gas exchange in oceanic upwelling regions for the case of nitrous oxide off Peru. In this region, routine concentration measurements from ships at 5 m or 10 m depth prove to overestimate surface (bulk) concentration. Thus, standard estimates of gas exchange will show systematic error. This is due to very shallow stratified layers that inhibit exchange between surface water and waters below and can exist for several days. Maximum bias occurs in moderate wind conditions.
Mingxi Yang, Thomas G. Bell, Ian J. Brown, James R. Fishwick, Vassilis Kitidis, Philip D. Nightingale, Andrew P. Rees, and Timothy J. Smyth
Biogeosciences, 16, 961–978,Short summary
We quantify the emissions and uptake of the greenhouse gases carbon dioxide and methane from the coastal seas of the UK over 1 year using the state-of-the-art eddy covariance technique. Our measurements show how these air–sea fluxes vary twice a day (tidal), diurnally (circadian) and seasonally. We also estimate the air–sea gas transfer velocity, which is essential for modelling and predicting coastal air-sea exchange.
Riley X. Brady, Nicole S. Lovenduski, Michael A. Alexander, Michael Jacox, and Nicolas Gruber
Biogeosciences, 16, 329–346,
Stelios Myriokefalitakis, Akinori Ito, Maria Kanakidou, Athanasios Nenes, Maarten C. Krol, Natalie M. Mahowald, Rachel A. Scanza, Douglas S. Hamilton, Matthew S. Johnson, Nicholas Meskhidze, Jasper F. Kok, Cecile Guieu, Alex R. Baker, Timothy D. Jickells, Manmohan M. Sarin, Srinivas Bikkina, Rachel Shelley, Andrew Bowie, Morgane M. G. Perron, and Robert A. Duce
Biogeosciences, 15, 6659–6684,Short summary
The first atmospheric iron (Fe) deposition model intercomparison is presented in this study, as a result of the deliberations of the United Nations Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP; http://www.gesamp.org/) Working Group 38. We conclude that model diversity over remote oceans reflects uncertainty in the Fe content parameterizations of dust aerosols, combustion aerosol emissions and the size distribution of transported aerosol Fe.
Liliane Merlivat, Jacqueline Boutin, David Antoine, Laurence Beaumont, Melek Golbol, and Vincenzo Vellucci
Biogeosciences, 15, 5653–5662,Short summary
The fugacity of carbon dioxide in seawater (fCO2) was measured hourly in the surface waters of the NW Mediterranean Sea during two 3-year sequences separated by 18 years. A decrease of pH of 0.0022 yr−1 was computed. About 85 % of the accumulation of dissolved inorganic carbon (DIC) comes from chemical equilibration with increasing atmospheric CO2; the remaining 15 % accumulation is consistent with estimates of transfer of Atlantic waters through the Gibraltar Strait.
Amanda R. Fay, Nicole S. Lovenduski, Galen A. McKinley, David R. Munro, Colm Sweeney, Alison R. Gray, Peter Landschützer, Britton B. Stephens, Taro Takahashi, and Nancy Williams
Biogeosciences, 15, 3841–3855,Short summary
The Southern Ocean is highly under-sampled and since this region dominates the ocean sink for CO2, understanding change is critical. Here we utilize available observations to evaluate how the seasonal cycle, variability, and trends in surface ocean carbon in the well-sampled Drake Passage region compare to that of the broader subpolar Southern Ocean. Results indicate that the Drake Passage is representative of the broader region; however, additional winter observations would improve comparisons.
Cui-Ci Sun, Martin Sperling, and Anja Engel
Biogeosciences, 15, 3577–3589,Short summary
Biogenic gel particles such as transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP) are important components in the sea-surface microlayer (SML). Their potential role in air–sea gas exchange and in primary organic aerosol emission has generated considerable research interest. Our wind wave channel experiment revealed how wind speed controls the accumulation and size distribution of biogenic gel particles in the SML.
N. Precious Mongwe, Marcello Vichi, and Pedro M. S. Monteiro
Biogeosciences, 15, 2851–2872,Short summary
Here we analyze seasonal cycle of CO2 biases in 10 CMIP5 models in the SO. We find two main model biases; exaggeration of primary production such that biologically driven DIC changes mainly regulates FCO2 variability, and an overestimation of the role of solubility, such that changes in temperature dominantly drive FCO2 seasonal changes to an extent of opposing biological CO2 uptake in spring. CMIP5 models show greater zonal homogeneity in the seasonal cycle of FCO2 than observational products.
Allison R. Moreno, George I. Hagstrom, Francois W. Primeau, Simon A. Levin, and Adam C. Martiny
Biogeosciences, 15, 2761–2779,Short summary
To bridge the missing links between variable marine elemental stoichiometry, phytoplankton physiology and carbon cycling, we embed four environmentally controlled stoichiometric models into a five-box ocean model. As predicted each model varied in its influence on the biological pump. Surprisingly, we found that variation can lead to nonlinear controls on atmospheric CO2 and carbon export, suggesting the need for further studies of ocean C : P and the impact on ocean carbon cycling.
Luke Gregor, Schalk Kok, and Pedro M. S. Monteiro
Biogeosciences, 15, 2361–2378,Short summary
The Southern Ocean accounts for a large portion of the variability in oceanic CO2 uptake. However, the drivers of these changes are not understood due to a lack of observations. In this study, we used an ensemble of gap-filling methods to estimate surface CO2. We found that winter was a more important driver of longer-term variability driven by changes in wind stress. Summer variability of CO2 was driven primarily by increases in primary production.
Erik T. Buitenhuis, Parvadha Suntharalingam, and Corinne Le Quéré
Biogeosciences, 15, 2161–2175,Short summary
Thanks to decreases in CFC concentrations, N2O is now the third-most important greenhouse gas, and the dominant contributor to stratospheric ozone depletion. Here we estimate the ocean–atmosphere N2O flux. We find that an estimate based on observations alone has a large uncertainty. By combining observations and a range of model simulations we find that the uncertainty is much reduced to 2.45 ± 0.8 Tg N yr−1, and better constrained and at the lower end of the estimate in the latest IPCC report.
Sayaka Yasunaka, Eko Siswanto, Are Olsen, Mario Hoppema, Eiji Watanabe, Agneta Fransson, Melissa Chierici, Akihiko Murata, Siv K. Lauvset, Rik Wanninkhof, Taro Takahashi, Naohiro Kosugi, Abdirahman M. Omar, Steven van Heuven, and Jeremy T. Mathis
Biogeosciences, 15, 1643–1661,Short summary
We estimated monthly air–sea CO2 fluxes in the Arctic Ocean and its adjacent seas north of 60° N from 1997 to 2014, after mapping pCO2 in the surface water using a self-organizing map technique. The addition of Chl a as a parameter enabled us to improve the estimate of pCO2 via better representation of its decline in spring. The uncertainty in the CO2 flux estimate was reduced, and a net annual Arctic Ocean CO2 uptake of 180 ± 130 Tg C y−1 was determined to be significant.
Alizée Roobaert, Goulven G. Laruelle, Peter Landschützer, and Pierre Regnier
Biogeosciences, 15, 1701–1720,
Chao Zhang, Huiwang Gao, Xiaohong Yao, Zongbo Shi, Jinhui Shi, Yang Yu, Ling Meng, and Xinyu Guo
Biogeosciences, 15, 749–765,Short summary
This study compares the response of phytoplankton growth in the northwest Pacific to those in the Yellow Sea. In general, larger positive responses of phytoplankton induced by combined nutrients (in the subtropical gyre of the northwest Pacific) than those induced by a single nutrient (in the Kuroshio Extension and the Yellow Sea) from the dust are observed. We also emphasize the importance of an increase in bioavailable P stock for phytoplankton growth following dust addition.
Goulven G. Laruelle, Peter Landschützer, Nicolas Gruber, Jean-Louis Tison, Bruno Delille, and Pierre Regnier
Biogeosciences, 14, 4545–4561,
Melchor González-Dávila, J. Magdalena Santana Casiano, and Francisco Machín
Biogeosciences, 14, 3859–3871,Short summary
The Mauritanian–Cap Vert upwelling is shown to be sensitive to climate change forcing on upwelling processes, which strongly affects the CO2 surface distribution, ocean acidification rates, and air–sea CO2 exchange. We confirmed an upwelling intensification, an increase in the CO2 outgassing, and an important decrease in the pH of the surface waters. Upwelling areas are poorly studied and VOS lines are shown as one of the most significant contributors to our knowledge of the ocean's response.
Rachel Hussherr, Maurice Levasseur, Martine Lizotte, Jean-Éric Tremblay, Jacoba Mol, Helmuth Thomas, Michel Gosselin, Michel Starr, Lisa A. Miller, Tereza Jarniková, Nina Schuback, and Alfonso Mucci
Biogeosciences, 14, 2407–2427,Short summary
This study assesses the impact of ocean acidification on phytoplankton and its synthesis of the climate-active gas dimethyl sulfide (DMS), as well as its modulation, by two contrasting light regimes in the Arctic. The light regimes tested had no significant impact on either the phytoplankton or DMS concentration, whereas both variables decreased linearly with the decrease in pH. Thus, a rapid decrease in surface water pH could alter the algal biomass and inhibit DMS production in the Arctic.
Hilton B. Swan, Graham B. Jones, Elisabeth S. M. Deschaseaux, and Bradley D. Eyre
Biogeosciences, 14, 229–239,Short summary
We measured the sulfur gas dimethylsulfide (DMS) in marine air at a coral cay on the Great Barrier Reef. DMS is well known to be released from the world's oceans, but environmental evidence of coral reefs releasing DMS has not been clearly demonstrated. We showed the coral reef can sometimes release DMS to the air, which was seen as spikes above the DMS released from the ocean. The DMS from the reef supplements the DMS from the ocean to assist formation of clouds that influence local climate.
Stelios Myriokefalitakis, Athanasios Nenes, Alex R. Baker, Nikolaos Mihalopoulos, and Maria Kanakidou
Biogeosciences, 13, 6519–6543,Short summary
The global atmospheric cycle of P is simulated accounting for natural and anthropogenic sources, acid dissolution of dust aerosol and changes in atmospheric acidity. Simulations show that P-containing dust dissolution flux may have increased in the last 150 years but is expected to decrease in the future, and biological particles are important carriers of bioavailable P to the ocean. These insights to the P cycle have important implications for marine ecosystem responses to climate change.
Timothée Bourgeois, James C. Orr, Laure Resplandy, Jens Terhaar, Christian Ethé, Marion Gehlen, and Laurent Bopp
Biogeosciences, 13, 4167–4185,Short summary
The global coastal ocean took up 0.1 Pg C yr−1 of anthropogenic carbon during 1993–2012 based on new biogeochemical simulations with an eddying 3-D global model. That is about half of the most recent estimate, an extrapolation based on surface areas. It should not be confused with the continental shelf pump, perhaps 10 times larger, which includes natural as well as anthropogenic carbon. Coastal uptake of anthropogenic carbon is limited by its offshore transport.
Corinne Le Quéré, Erik T. Buitenhuis, Róisín Moriarty, Séverine Alvain, Olivier Aumont, Laurent Bopp, Sophie Chollet, Clare Enright, Daniel J. Franklin, Richard J. Geider, Sandy P. Harrison, Andrew G. Hirst, Stuart Larsen, Louis Legendre, Trevor Platt, I. Colin Prentice, Richard B. Rivkin, Sévrine Sailley, Shubha Sathyendranath, Nick Stephens, Meike Vogt, and Sergio M. Vallina
Biogeosciences, 13, 4111–4133,Short summary
We present a global biogeochemical model which incorporates ecosystem dynamics based on the representation of ten plankton functional types, and use the model to assess the relative roles of iron vs. grazing in determining phytoplankton biomass in the Southern Ocean. Our results suggest that observed low phytoplankton biomass in the Southern Ocean during summer is primarily explained by the dynamics of the Southern Ocean zooplankton community, despite iron limitation of phytoplankton growth.
R. Pereira, K. Schneider-Zapp, and R. C. Upstill-Goddard
Biogeosciences, 13, 3981–3989,Short summary
Understanding controls of air–sea gas exchange is necessary for predicting regional- and global-scale trace gas fluxes and feedbacks. Recent studies demonstrated the importance of surfactants, which occur naturally in the uppermost layer of coastal water bodies, to suppress the gas transfer velocity (kw). Here we present data for seawater samples collected from the North Sea. Using a novel analytical approach we show a strong seasonal and spatial relationship between natural surfactants and kw.
Melissa L. Breeden and Galen A. McKinley
Biogeosciences, 13, 3387–3396,Short summary
Natural variability of the North Atlantic carbon cycle is modeled for 1948–2009. The dominant mode of surface ocean CO2 variability is associated with sea surface temperature (SST) variability composed of (a) the Atlantic Multidecadal Oscillation (AMO) and (b) a positive SST trend. In the subpolar gyre, positive AMO is associated with reduced vertical mixing that lowers pCO2. In the subtropical gyre, AMO-associated warming increases pCO2. Since 1980, the SST trend has amplified AMO impacts.
Anja Engel and Luisa Galgani
Biogeosciences, 13, 989–1007,Short summary
The sea-surface microlayer (SML) is a very thin layer at the interface between the ocean and the atmosphere. Organic compounds in the SML may influence the exchange of gases between seawater and air, as well as primary aerosol emission. Here, we report results from the SOPRAN M91 cruise, a field study to the coastal upwelling regime off Peru's coast in 2012. Our study provides novel insight to the relationship between plankton productivity, wind speed and organic matter accumulation in the SML.
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.
A. R. Baker, M. Thomas, H. W. Bange, and E. Plasencia Sánchez
Biogeosciences, 13, 817–825,Short summary
Concentrations of major ions and trace metals were measured in aerosols off the coast of Peru in December 2012. A few trace metals (iron, copper, nickel, and cobalt) had anomalously high concentrations, which may be associated with industrial metal smelting activities in the region. The atmosphere appears to supply an excess of iron (relative to atmospheric nitrogen supply) to the phytoplankton community of the Peruvian upwelling system.
C. Walker Brown, J. Boutin, and L. Merlivat
Biogeosciences, 12, 7315–7329,Short summary
Using a temperature-salinity-based extrapolation of in situ surface-fCO2, in conjunction with SMOS SSS and OSTIA SST, fCO2 is mapped within the eastern tropical Pacific Ocean (ETPO) at high spatial (0.25°) and temporal (monthly) resolution. Strong interannual and spatial variability is identified, with net outgassing of CO2 in the gulfs of Tehuantepec and Papagayo contrasting net ingassing in the Gulf of Panama. For the period of July 2010-July 2014, the ETPO was supersaturated by ~40μatm.
C. Rödenbeck, D. C. E. Bakker, N. Gruber, Y. Iida, A. R. Jacobson, S. Jones, P. Landschützer, N. Metzl, S. Nakaoka, A. Olsen, G.-H. Park, P. Peylin, K. B. Rodgers, T. P. Sasse, U. Schuster, J. D. Shutler, V. Valsala, R. Wanninkhof, and J. Zeng
Biogeosciences, 12, 7251–7278,Short summary
This study investigates variations in the CO2 uptake of the ocean from year to year. These variations have been calculated from measurements of the surface-ocean carbon content by various different interpolation methods. The equatorial Pacific is estimated to be the region with the strongest year-to-year variations, tied to the El Nino phase. The global ocean CO2 uptake gradually increased from about the year 2000. The comparison of the interpolation methods identifies these findings as robust.
A. Varenik, S. Konovalov, and S. Stanichny
Biogeosciences, 12, 6479–6491,Short summary
Atmospheric deposition of inorganic fixed nitrogen has been evaluated and quantified for the Black Sea at different spatial and temporal scales. The effect of this deposition has appeared comparable to riverine load of nutrients. This atmospheric deposition can dramatically increase primary production with the major effects for off-shore regions. It does support the currently highly eutrophic state of the Black Sea and prevents rehabilitation of this ecosystem.
H. Hepach, B. Quack, S. Raimund, T. Fischer, E. L. Atlas, and A. Bracher
Biogeosciences, 12, 6369–6387,Short summary
This manuscript covers the first measurements of CHBr3, CH2Br2 and CH3I from the equatorial Atlantic during the Cold Tongue season, identifying this region and season as a source for these compounds. For the first time, we calculated diapycnal fluxes, and showed that the fluxes from below the mixed layer to the surface are not sufficient to balance the mixed layer budget. Hence, we conclude that mixed layer production has to take place despite a pronounced sub-mixed-layer-maximum.
L. C. Cotovicz Jr., B. A. Knoppers, N. Brandini, S. J. Costa Santos, and G. Abril
Biogeosciences, 12, 6125–6146,Short summary
Air-water CO2 fluxes were monitored in Guanabara Bay (Brazil), a tropical eutrophic coastal embayment. In contrast to other estuaries worldwide, Guanabara Bay behaves as an annual CO2 sink (-9.6 to -18.3 molC m2 yr) due to the concomitant effects of strong radiation, thermal stratification, and high availability of nutrients, which promotes huge phytoplankton development and autotrophy. Our results show that CO2 budget assertions still lack information on tropical marine-dominated estuaries.
A. Joesoef, W.-J. Huang, Y. Gao, and W.-J. Cai
Biogeosciences, 12, 6085–6101,Short summary
In this paper, we report the ﬁrst seasonal distribution of pCO2 and air–water CO2 ﬂux in the Delaware Estuary. We further assess the temperature and biological effects on pCO2 distributions as well as the overall contribution of internal versus riverine sources on CO2 inputs to the estuarine system. Finally, we present a summarized pCO2 distribution over the study area and provide a conceptual model to illustrate the control mechanisms on surface water CO2 dynamics in the Delaware Estuary.
Y. Zhang, N. Mahowald, R. A. Scanza, E. Journet, K. Desboeufs, S. Albani, J. F. Kok, G. Zhuang, Y. Chen, D. D. Cohen, A. Paytan, M. D. Patey, E. P. Achterberg, J. P. Engelbrecht, and K. W. Fomba
Biogeosciences, 12, 5771–5792,Short summary
A new technique to determine a size-fractionated global soil elemental emission inventory based on a global soil and mineralogical data set is introduced. Spatial variability of mineral dust elemental fractions (8 elements, e.g., Ca, Fe, Al) is identified on a global scale, particularly for Ca. The Ca/Al ratio ranged between 0.1 and 5.0 and is confirmed as an indicator of dust source regions by a global dust model. Total and soluble dust element fluxes into different ocean basins are estimated.
P. Marrec, T. Cariou, E. Macé, P. Morin, L. A. Salt, M. Vernet, B. Taylor, K. Paxman, and Y. Bozec
Biogeosciences, 12, 5371–5391,
L. Merlivat, J. Boutin, and F. d'Ovidio
Biogeosciences, 12, 3513–3524,Short summary
One CARIOCA buoy deployed during the KEOPS2 expedition in Oct-Nov 2011 drifted eastward in the Kerguelen plume. Surface measurements of pCO2 and O2 were collected. Close to the polar front, the surface waters are a sink for CO2 and a source for O2, with mean fluxes equal to -8mmol CO2 m-2d-1 and +38mmol O2 m-2d-1. Outside an iron-enriched filament, the fluxes are in the opposite direction. NCP values of 60-140 mmol C m-2d-1 and stoichiometric ratios, O2/C, between 1.1 and 1.4 are computed.
G. Parard, A. A. Charantonis, and A. Rutgerson
Biogeosciences, 12, 3369–3384,Short summary
In this paper, we used combines two existing methods (i.e. self-organizing maps and multiple linear regression) to estimate the ocean surface partial pressure of CO2 in the Baltic Sea from the remotely sensed sea surface temperature, chlorophyll, coloured dissolved organic matter, net primary production, and mixed-layer depth. The outputs of this research have a horizontal resolution of 4km and cover the 1998–2011 period. These outputs give a monthly map of the Baltic Sea.
K. Violaki, J. Sciare, J. Williams, A. R. Baker, M. Martino, and N. Mihalopoulos
Biogeosciences, 12, 3131–3140,
A. S. Lansø, J. Bendtsen, J. H. Christensen, L. L. Sørensen, H. Chen, H. A. J. Meijer, and C. Geels
Biogeosciences, 12, 2753–2772,Short summary
The air-sea CO2 exchange is investigated in the coastal region of the Baltic Sea and Danish inner waters. The impact of short-term variability in atmospheric CO2 on the air-sea CO2 exchange is examined, and it is found that ignoring short-term variability in the atmospheric CO2 creates a significant bias in the CO2 exchange. Atmospheric short-term variability is not always included in studies of the air-sea CO2 exchange, but based on the present study, we recommend it to be so in the future.
L. Meire, D. H. Søgaard, J. Mortensen, F. J. R. Meysman, K. Soetaert, K. E. Arendt, T. Juul-Pedersen, M. E. Blicher, and S. Rysgaard
Biogeosciences, 12, 2347–2363,Short summary
The Greenland Ice Sheet releases large amounts of freshwater, which strongly influences the biogeochemistry of the adjacent fjord systems and continental shelves. Here we present seasonal observations of the carbonate system in the surface waters of a west Greenland tidewater outlet glacier fjord. Our data reveal a permanent undersaturation of CO2 in the surface layer of the entire fjord and adjacent shelf, creating a high annual uptake of 65gCm-2yr-1.
N.-X. Geilfus, R. J. Galley, O. Crabeck, T. Papakyriakou, J. Landy, J.-L. Tison, and S. Rysgaard
Biogeosciences, 12, 2047–2061,Short summary
We investigated the evolution of inorganic carbon within landfast sea ice in Resolute Passage during the spring and summer melt period. Low TA and TCO2 concentrations observed in sea ice and brine were associated with the percolation of meltwater from melt ponds. Meltwater was continuously supplied to the ponds which prevented melt ponds from fully equilibrating with the atmospheric CO2 concentration, promoting a continuous uptake of CO2 from the atmosphere.
J. Palmiéri, J. C. Orr, J.-C. Dutay, K. Béranger, A. Schneider, J. Beuvier, and S. Somot
Biogeosciences, 12, 781–802,Short summary
Different observational-based estimates of CO2 uptake and resulting acidification of the Mediterranean Sea vary widely. A new study finds that even the smallest of those are an upper limit because the approach used assumes air-sea CO2 equilibrium. Then with a lower limit from new fine-scale numerical model simulations, the authors bracket Mediterranean Sea CO2 uptake and acidification rates. They conclude that its rate of surface acidifcation is much like that for typical ocean waters.
N. Meskhidze, A. Sabolis, R. Reed, and D. Kamykowski
Biogeosciences, 12, 637–651,
E. C. Leedham Elvidge, S.-M. Phang, W. T. Sturges, and G. Malin
Biogeosciences, 12, 387–398,
Auble, D. L. and Meyers, T. P.: An open path, fast response infrared absorption gas analyzer for H2O and CO2, Bound.-Lay. Meteorol., 59, 243–256, https://doi.org/10.1007/BF00119815, 1992.
Bakun, A.: Global Climate Change and Intensification of Coastal Ocean Upwelling, Science, 247, 198–201, https://doi.org/10.1126/science.247.4939.198, 1990.
Borges, A. V.: Present Day Carbon Dioxide Fluxes in the Coastal Ocean and Possible Feedbacks Under Global Change, in: Oceans and the Atmospheric Carbon Content, edited by: Duarte, P. and Santana-Casiano, J. M., 47–77, Springer, the Netherlands, 2011.
Borges, A. V. and Frankignoulle, M.: Distribution of surface carbon dioxide and air-sea exchange in the upwelling system off the Galician coast, Global Biogeochem. Cy., 16, 1020, https://doi.org/10.1029/2000GB001385, 2002.
Burba, G. G. and Anderson, D. J.: A brief Practical Guide to Eddy Covariance Flux Measurements: Principles and Workflow Examples for Scientific and Industrial Applications, Li-COR Biosciences, Lincoln, USA, 2010.
Burba, G. G., McDermitt, D. K., Grelle, A., Anderson, D. J., and Xu, L.: Addressing the influence of instrument surface heat exchange on the measurements of CO2 flux from open-path gas analyzers, Glob. Change Biol., 14, 1854–1876, https://doi.org/10.1111/j.1365-2486.2008.01606.x, 2008.
Chen, C.-T. A. and Borges, A. V.: Reconciling opposing views on carbon cycling in the coastal ocean: Continental shelves as sinks and near-shore ecosystems as sources of atmospheric CO2, Deep-Sea Res. Pt. II, 56, 578–590, https://doi.org/10.1016/j.dsr2.2009.01.001, 2009.
Copin-Montegut, C. and Raimbault, P.: The Peruvian upwelling near 15° S in August 1986. Results of continuous measurements of physical and chemical properties between 0 and 200 m depth, Deep-Sea Res. Pt. I, 41, 439–467, 1994.
Day, D. A. and Faloona, I.: Carbon monoxide and chromophoric dissolved organic matter cycles in the shelf waters of the northern California upwelling system, J. Geophys. Res., 114, C01006, https://doi.org/10.1029/2007JC004590, 2009.
Diffenbaugh, N. S., Snyder, M. A., and Sloan, L. C.: Could CO2-Induced Land-Cover Feedbacks Alter Near-Shore Upwelling Regimes?, PNAS, 101, 27–32, https://doi.org/10.1073/pnas.0305746101, 2004.
Doney, S. C., Tilbrook, B., Roy, S., Metzl, N., Le Quéré, C., Hood, M., Feely, R. A., and Bakker, D.: Surface-ocean CO2 variability and vulnerability, Deep-Sea Res. Pt. II, 56, 504–511, https://doi.org/10.1016/j.dsr2.2008.12.016, 2009.
Dorman, C. E., Holt, T., Rogers, D. P., and Edwards, K.: Large-Scale Structure of the June–July 1996 Marine Boundary Layer along California and Oregon, Month. Weather Rev., 128, 1632–1652, https://doi.org/10.1175/1520-0493(2000)128<1632:LSSOTJ>2.0.CO;2, 2000.
Dugdale, R. C., Wilkerson, F. P., Hogue, V. E., and Marchi, A.: Nutrient controls on new production in the Bodega Bay, California, coastal upwelling plume, Deep-Sea Res. Pt. II, 53, 3049–3062, https://doi.org/10.1016/j.dsr2.2006.07.009, 2006.
Else, B. G. T., Papakyriakou, T. N., Galley, R. J., Drennan, W. M., Miller, L. A., and Thomas, H.: Wintertime CO2 fluxes in an Arctic polynya using eddy covariance: Evidence for enhanced air-sea gas transfer during ice formation, J. Geophys. Res., 116, C00G03, https://doi.org/10.1029/2010JC006760, 2011.
Evans, W., Hales, B., and Strutton, P. G.: Seasonal cycle of surface ocean pCO2 on the Oregon shelf, J. Geophys. Res., 116, C05012, https://doi.org/10.1029/2010JC006625, 2011.
Feely, R. A., Sabine, C. L., Hernandez-Ayon, J. M., Ianson, D., and Hales, B.: Evidence for Upwelling of Corrosive "Acidified" Water onto the Continental Shelf, Science, 320, 1490–1492, https://doi.org/10.1126/science.1155676, 2008.
Foken, T. and Wichura, B.: Tools for quality assessment of surface-based flux measurements, Agric. Forest Meteorol., 78, 83–105, 1996.
Frew, N. M., Bock, E. J., Schimpf, U., Hara, T., Haußecker, H., Edson, J. B., McGillis, W. R., Nelson, R. K., McKenna, S. P., Uz, B. M., and Jähne, B.: Air-sea gas transfer: Its dependence on wind stress, small-scale roughness, and surface films, J. Geophys. Res., 109, C08S17, https://doi.org/10.1029/2003JC002131, 2004.
Friederich, G. E., Walz, P. M., Burczynski, M. G., and Chavez, F. P.: Inorganic carbon in the central California upwelling system during the 1997-1999 El Niño-La Niña event, Prog. Oceanogr., 54, 185–203, 2002.
Gago, J., Gilcoto, M., Pérez, F., and Rìos, A. .: Short-term variability of fCO2 in seawater and air–sea CO2 fluxes in a coastal upwelling system (Rìa de Vigo, NW Spain), Mar. Chem., 80, 247–264, https://doi.org/10.1016/S0304-4203(02)00117-2, 2003.
Garcia-Reyes, M.: Variability in Coastal Upwelling off Central and Northern California, Doctoral dissertation of the University of California, Davis, 2011.
Garcia-Reyes, M. and Largier, J.: Observations of increased wind-driven coastal upwelling off central California, J. Geophys. Res., 115, C04011, https://doi.org/10.1029/2009JC005576, 2010.
Gattuso, J. P., Frankignoulle, M., and Wollast, R.: Carbon and carbonate metabolism in coastal aquatic ecosystems, Annu. Rev. Ecol. Syst., 29, 405–434, 1998.
Goyet, C., Millero, F. J., O'Sullivan, D. W., Eischeid, G., McCue, S. J., and Bellerby, R. G. J.: Temporal variations of pCO2 in surface seawater of the Arabian Sea in 1995, Deep-Sea Res. Pt. I, 45, 609–623, 1998.
Gruber, N., Gloor, M., Fletcher, S. E. M., Doney, S. C., Dutkiewicz, S., Follows, M. J., Gerber, M., Jacobson, A. R., Joos, F., Lindsay, K., Menemenlis, D., Mouchet, A., Müller, S. A., Sarmiento, J. L., and Takahashi, T.: Oceanic sources, sinks, and transport of atmospheric CO2, Global Biogeochem. Cycles, 23, GB1005, https://doi.org/10.1029/2008GB003349, 2009.
Hales, B., Takahashi, T., and Bandstra, L.: Atmospheric CO2 uptake by a coastal upwelling system, Global Biogeochem. Cy., 19, GB1009, https://doi.org/10.1029/2004GB002295, 2005.
Hauri, C., Gruber, N., Vogt, M., Doney, S. C., Feely, R. A., Lachkar, Z., Leinweber, A., McDonnell, A. M. P., Munnich, M., and Plattner, G.-K.: Spatiotemporal variability and long-term trends of ocean acidification in the California Current System, Biogeosciences Discussions, 9, 10371–10428, https://doi.org/10.5194/bgd-9-10371-2012, 2012.
Ho, D. T., Law, C. S., Smith, M. J., Schlosser, P., Harvey, M., and Hill, P.: Measurements of air-sea gas exchange at high wind speeds in the Southern Ocean: Implications for global parameterizations, Geophys. Res. Lett., 33, 16611, https://doi.org/10.1029/2006GL026817, 2006.
Ianson, D. and Allen, S. E.: A two-dimensional nitrogen and carbon flux model in a coastal upwelling region, Global Biogeochem. Cy., 16, p. 1011, 2002.
Ianson, D., Feely, R. A., Sabine, C. L., and Juranek, L. W.: Features of coastal upwelling regions that determine net air-sea CO2 flux, J. Oceanogr., 65, 677–687, 2009.
Ikawa, H.: Air-sea CO2 exchange of the coastal marine zone. Doctoral dissertation of the Joint Doctoral Program in Ecology of University of California, Davis and San Diego State University, University of California, Davis and San Diego State University, March, 2013.
Ikawa, H. and Oechel, W. C.: Air–sea CO2 exchange of beach and near-coastal waters of the Chukchi Sea near Barrow, Alaska, Cont. Shelf Res., 31., 1357–1364, https://doi.org/10.1016/j.csr.2011.05.012, 2011.
Iwata, T., Yoshikawa, K., Higuchi, Y., Yamashita, T., Kato, S., and Ohtaki, E.: The Spectral Density Technique for the Determination of CO2 Flux Over the Ocean, Bound-Lay. Meteorol., 117, 511–523, https://doi.org/10.1007/s10546-005-2773-4, 2005.
Jähne, B., Münnich, K. O., Dutzi, R. B. A., Huber, W., and Libner, P.: On the Parameters Influencing Air-Water Gas Exchange, J. Geophys. Res., 92, 1937–1949, https://doi.org/10.1029/JC092iC02p01937, 1987.
Kahru, M. and Mitchell, B. G.: Influence of the El Niño-La Niña cycle on satellite-derived primary production in the California Current, Geophys. Res. Lett., 29, 1846, https://doi.org/10.1029/2002GL014963, 2002.
Kaimal, J. C., Wyngaard, J. C., Izumi, Y., and Cote, O. R.: Spectral characteristics of surface-layer turbulence, Quart. J. Roy. Meteorol. Soc., 98, 563–589, 1972.
Keeling, R. F.: On the role of large bubbles in air-sea gas exchange and supersaturation in the ocean, J. Mar. Res., 51, 237–271, https://doi.org/10.1357/0022240933223800, 1993.
Kelley, J. J. and Hood, D. W.: Carbon Dioxide in the Pacific Ocean and Bering Sea: Upwelling and Mixing, J. Geophys. Res., 76, PP. 745–752, https://doi.org/10.1029/JC076i003p00745, 1971.
Kondo, F. and Tsukamoto, O.: Air-sea CO2 flux by eddy covariance technique in the equatorial Indian Ocean, J. Oceanogr., 63, 449–456, 2007.
Largier, J. L., Lawrence, C. A., Roughan, M., Kaplan, D. M., Dever, E. P., Dorman, C. E., Kudela, R. M., Bollens, S. M., Wilkerson, F. P., and Dugdale, R. C.: WEST: A northern California study of the role of wind-driven transport in the productivity of coastal plankton communities, Deep-Sea Res. Pt. II, 53, 2833–2849, 2006.
Lendt, R., Thomas, H., Hupe, A., and Ittekkot, V.: Response of the near-surface carbonate system of the northwestern Arabian Sea to the southwest monsoon and related biological forcing, J. Geophys. Res., 108, 3222, https://doi.org/10.1029/2000JC000771, 2003.
Lentz, S. J.: The surface boundary layer in coastal upwelling regions, J. Phys. Oceanogr., 22, 1517–1539, 1992.
Nightingale, P. D., Malin, G., Law, C. S., Watson, A. J., Liss, P. S., Liddicoat, M. I., Boutin, J., and Upstill-Goddard, R. C.: In situ evaluation of air-sea gas exchange parameterizations using novel conservative and volatile tracers, Global Biogeochem. Cy., 14, 373–387, https://doi.org/10.1029/1999GB900091, 2000.
Papale, D., Reichstein, M., Aubinet, M., Canfora, E., Bernhofer, C., Kutsch, W., Longdoz, B., Rambal, S., Valentini, R., Vesala, T., and Yakir, D.: Towards a standardized processing of Net Ecosystem Exchange measured with eddy covariance technique: algorithms and uncertainty estimation, Biogeosciences, 3, 571–583, https://doi.org/10.5194/bg-3-571-2006, 2006.
Prytherch, J., Yelland, M. J., Pascal, R. W., Moat, B. I., Skjelvan, I., and Neill, C. C.: Direct measurements of the CO2 flux over the ocean: Development of a novel method, Geophys. Res. Lett., 37, L03607, https://doi.org/10.1029/2009GL041482, 2010.
Sabine, C. L., Feely, R. A., Gruber, N., Key, R. M., Lee, K., Bullister, J. L., Wanninkhof, R., Wong, C. S., Wallace, D. W. R., Tilbrook, B., Millero, F. J., Peng, T.-H., Kozyr, A., Ono, T., and Rios, A. F.: The Oceanic Sink for Anthropogenic CO2, Science, 305, 367–371, https://doi.org/10.1126/science.1097403, 2004.
Sachs, L.: Angewandte Statistik: Anwendung Statistischer Methoden, Springer, Berlin, 1996.
Sarmiento, J. L. and Gruber, N.: Ocean Biogeochemical Dynamics, Princeton University Press, Princeton, 2006.
Schuepp, P. H., Leclerc, M. Y., MacPherson, J. I., and Desjardins, R. L.: Footprint prediction of scalar fluxes from analytical solutions of the diffusion equation, Bound-Lay. Meteorol., 50, 355–373, 1990.
Simpson, J. J. and Zirino, A.: Biological control of pH in the Peruvian coastal upwelling area, Deep-Sea Res., 27, 733–743, 1980.
Sweeney, C., Gloor, E., Jacobson, A. R., Key, R. M., Mckinley, G., Sarmiento, J. L., and Wanninkhof, R.: Constraining global air-sea gas exchange for CO2 with recent bomb 14C measurements, Global Biogeochem. Cy., 21, GB2015, https://doi.org/10.1029/2006GB002784, 2007.
Takahashi, T., Sutherland, S. C., Wanninkhof, R., Sweeney, C., Feely, R. A., Chipman, D. W., Hales, B., Friederich, G., Chavez, F., Sabine, C., Watson, A., Bakker, D. C. E., Schuster, U., Metzl, N., Yoshikawa-Inoue, H., Ishii, M., Midorikawa, T., Nojiri, Y., Körtzinger, A., Steinhoff, T., Hoppema, M., Olafsson, J., Arnarson, T. S., Tilbrook, B., Johannessen, T., Olsen, A., Bellerby, R., Wong, C. S., Delille, B., Bates, N. R., and de Baar, H. J. W.: Climatological mean and decadal change in surface ocean pCO2, and net sea–air CO2 flux over the global oceans, Deep-Sea Res. Pt. II, 56, 554–577, https://doi.org/10.1016/j.dsr2.2008.12.009, 2009.
Tanner, C. B. and Thurtell, G. W.: Anemoclinometer measurements of Reynolds stress and heat transport in the atmospheric surface layer, ECOM, United States Army Electroniocs Command, Research and Development Technical Report, ECOM 66-66-G22-F, 1969.
Torres, R., Turner, D. R., Silva, N., and Rutllant, J.: High short-term variability of CO2 fluxes during an upwelling event off the Chilean coast at 30° S, Deep-Sea Res. Pt. I, 46, 1161–1179, https://doi.org/10.1016/S0967-0637(99)00003-5, 1999.
Vickers, D. and Mahrt, L.: Quality Control and Flux Sampling Problems for Tower and Aircraft Data, Journal of Atmospheric and Oceanic Technology, 14, 512–526, https://doi.org/10.1175/1520-0426(1997)014<0512:QCAFSP>2.0.CO;2, 1997.
Wanninkhof, R.: Relationship between wind speed and gas exchange over the ocean, J. Geophys. Res., 97, 7373–7382, https://doi.org/10.1029/92JC00188, 1992.
Wanninkhof, R. and McGillis, W. R.: A cubic relationship between air-sea CO2 exchange and wind speed, Geophys. Res. Lett., 26, 1889–1892, https://doi.org/10.1029/1999GL900363, 1999.
Webb, E. K., Pearman, G. I., and Leuning, R.: Correction of flux measurements for density effects due to heat and water vapour transfer, Quart. J. Roy. Meteorol. Soc., 106, 85–100, https://doi.org/10.1002/qj.49710644707, 1980.
Weiss, R. F.: Carbon dioxide in water and seawater: the solubility of a non-ideal gas, Mar. Chem., 2, 203–215, https://doi.org/10.1016/0304-4203(74)90015-2, 1974.
Wilkerson, F. P., Lassiter, A. M., Dugdale, R. C., Marchi, A., and Hogue, V. E.: The phytoplankton bloom response to wind events and upwelled nutrients during the CoOP WEST study, Deep-Sea Res. Pt. II, 53, 3023–3048, 2006.
Zhang, J., Lee, X., Song, G., and Han, S.: Pressure correction to the long-term measurement of carbon dioxide flux, Agr. Forest Meteorol., 151, 70–77, https://doi.org/10.1016/j.agrformet.2010.09.004, 2011.