WorldWideScience

Sample records for benthic carbon budget

  1. BENTHIC METABOLISM ON A SHELTERED ROCKY SHORE: ROLE OF THE CANOPY IN THE CARBON BUDGET(1).

    Science.gov (United States)

    Golléty, Claire; Migné, Aline; Davoult, Dominique

    2008-10-01

    While the importance of canopy-forming algae in structuring ecosystems is recognized, their role in the carbon budget is still not well understood. To our knowledge, no measurements of rocky shores primary production and respiration under emersion periods have been carried out in situ. A benthic chamber coupled to a CO2 -infrared gas analyzer was used to measure gross primary production and respiration on the Ascophyllum nodosum (L.) Le Jol. zone of a sheltered rocky shore in Brittany, France. Over a year of monthly measurements on the zone with and without the A. nodosum canopy showed fairly high production and respiration values for the global community as well as carbon fluxes due to the canopy that largely dominated the benthic metabolism of the zone. The strong canopy respiration relative to the primary production also suggested a high metabolic activity by microscopic heterotrophs on the surface of the alga. Both the canopy and the understory annual primary production and respiration were under the control of light and temperature seasonal variations. Finally, the range of the amount of carbon produced on the A. nodosum zone during diurnal emersions was estimated. Additional measures accounting for the day-night cycles and seasonal light variations over an entire tidal cycle are, however, necessary to establish an annual carbon budget. Such measures using the benthic chamber together with complementary techniques would allow a better understanding of the functioning of sheltered rocky shores.

  2. A benthic carbon budget for the continental slope off Cape Hatteras, N.C.

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, C.J.; Blair, N.E.; DeMaster, D.J.; Jahnke, R.A.; Martens, C.S.

    1999-01-31

    The continental slope off Cape Hatteras, N.C. from approximately 36{degree} 00 minutes N to 35{degree} 20 minutes N is a region of relatively rapid sediment accumulation, organic matter deposition and subsequent remineralization. The measured fluxes are the highest reported for the slope off the eastern US Sediment accumulation rates range from 40 to 140 cm ky{sup -1}. Organic carbon deposition rates range from 3.5 to 7.4 moles C m{sup -2} yr{sup -1}. The areal coverage of this ''depocenter'' is probably controlled by interactions between physical oceanographic processes and the rugged topography of the seafloor. The organic matter deposited on the seafloor is primarily marine in origin and a mix of old and fresh particles. 73-93% of the depositing detritus is rapidly oxidized near the sediment/water interface. The controls on subsurface remineralization appear to be a complex function of the relative amount of metabolizable carbon delivered to the seabed both now and in the distant past (>=500ybp) and the extent of seabed irrigation. The age of DIC and CH{sub 4} produced within the seabed indicates that relatively young, reactive carbon is advected below the sediment surface and fuels subsurface remineralization. The stable isotopic composition of DIC produced within the seabed indicates the selective degradation of {sup 13}C-enriched fractions of the organic matter. The metabolizable fraction has a carbon isotopic signature of approx. -18{per_thousand};, while the organic matter that survives degradation and is buried has a d{sup 13}C closer to -20{per_thousand}.

  3. Phytopigments and fatty acids in the gut of the deposit-feeding heart urchin Echinocardium cordatum in the southern North Sea: Selective feeding and its contribution to the benthic carbon budget

    Science.gov (United States)

    Boon, Arjen R.; Duineveld, Gerard C. A.

    2012-01-01

    As part of a broader study on benthic-pelagic coupling in the southern North Sea, specimens of the common heart urchin Echinocardium cordatum were sampled for analyses on phytopigments and fatty acids in their guts. Results were interpreted in the context of feeding and ecological functioning of the heart urchins in the benthic system. Ingestion selection factors for both component groups were relatively high, 5 to 9 for chlorophyll a and 9 to 130 for total fatty acids. The data point to at least partially different sources of the pigments and of the fatty acids. Next to algal detritus, small infauna relatively rich in fatty acids might be preferentially co-ingested with the detritus. Due to digestive breakdown and absorption, the concentrations of pigments and fatty acids were importantly decreased, indicating a rather high digestion efficiency for this subsurface deposit feeder, up to 80%. The results indicate that E. cordatum increases its energy acquisition by strong selectivity and a high digestive efficiency. Optimal foraging is likely to apply on deposit-feeding invertebrates in relatively food-rich coastal environments as much as it does in the food-poor deep-sea environment. Using chlorophyll a as a proxy for carbon, the contribution of the urchin population to the momentary benthic carbon budget was calculated at 7% to 42%.

  4. Global Carbon Budget 2016

    Science.gov (United States)

    Le Quéré, Corinne; Andrew, Robbie M.; Canadell, Josep G.; Sitch, Stephen; Korsbakken, Jan Ivar; Peters, Glen P.; Manning, Andrew C.; Boden, Thomas A.; Tans, Pieter P.; Houghton, Richard A.; Keeling, Ralph F.; Alin, Simone; Andrews, Oliver D.; Anthoni, Peter; Barbero, Leticia; Bopp, Laurent; Chevallier, Frédéric; Chini, Louise P.; Ciais, Philippe; Currie, Kim; Delire, Christine; Doney, Scott C.; Friedlingstein, Pierre; Gkritzalis, Thanos; Harris, Ian; Hauck, Judith; Haverd, Vanessa; Hoppema, Mario; Klein Goldewijk, Kees; Jain, Atul K.; Kato, Etsushi; Körtzinger, Arne; Landschützer, Peter; Lefèvre, Nathalie; Lenton, Andrew; Lienert, Sebastian; Lombardozzi, Danica; Melton, Joe R.; Metzl, Nicolas; Millero, Frank; Monteiro, Pedro M. S.; Munro, David R.; Nabel, Julia E. M. S.; Nakaoka, Shin-ichiro; O'Brien, Kevin; Olsen, Are; Omar, Abdirahman M.; Ono, Tsuneo; Pierrot, Denis; Poulter, Benjamin; Rödenbeck, Christian; Salisbury, Joe; Schuster, Ute; Schwinger, Jörg; Séférian, Roland; Skjelvan, Ingunn; Stocker, Benjamin D.; Sutton, Adrienne J.; Takahashi, Taro; Tian, Hanqin; Tilbrook, Bronte; van der Laan-Luijkx, Ingrid T.; van der Werf, Guido R.; Viovy, Nicolas; Walker, Anthony P.; Wiltshire, Andrew J.; Zaehle, Sönke

    2016-11-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere - the "global carbon budget" - is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates and consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models. We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ±1σ, reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2006-2015), EFF was 9

  5. Global Carbon Budget 2015

    Science.gov (United States)

    Le Quéré, C.; Moriarty, R.; Andrew, R. M.; Canadell, J. G.; Sitch, S.; Korsbakken, J. I.; Friedlingstein, P.; Peters, G. P.; Andres, R. J.; Boden, T. A.; Houghton, R. A.; House, J. I.; Keeling, R. F.; Tans, P.; Arneth, A.; Bakker, D. C. E.; Barbero, L.; Bopp, L.; Chang, J.; Chevallier, F.; Chini, L. P.; Ciais, P.; Fader, M.; Feely, R. A.; Gkritzalis, T.; Harris, I.; Hauck, J.; Ilyina, T.; Jain, A. K.; Kato, E.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landschützer, P.; Lauvset, S. K.; Lefèvre, N.; Lenton, A.; Lima, I. D.; Metzl, N.; Millero, F.; Munro, D. R.; Murata, A.; Nabel, J. E. M. S.; Nakaoka, S.; Nojiri, Y.; O'Brien, K.; Olsen, A.; Ono, T.; Pérez, F. F.; Pfeil, B.; Pierrot, D.; Poulter, B.; Rehder, G.; Rödenbeck, C.; Saito, S.; Schuster, U.; Schwinger, J.; Séférian, R.; Steinhoff, T.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tilbrook, B.; van der Laan-Luijkx, I. T.; van der Werf, G. R.; van Heuven, S.; Vandemark, D.; Viovy, N.; Wiltshire, A.; Zaehle, S.; Zeng, N.

    2015-12-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and a methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates as well as consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover-change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models forced by observed climate, CO2, and land-cover change (some including nitrogen-carbon interactions). We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ±1σ, reflecting the current capacity to characterise the annual estimates of each component of the global

  6. Global Carbon Budget 2016

    NARCIS (Netherlands)

    Quéré, Le Corinne; Andrew, Robbie M.; Canadell, Josep G.; Sitch, Stephen; Korsbakken, Jan Ivar; Peters, Glen P.; Manning, Andrew C.; Boden, Thomas A.; Tans, Pieter P.; Houghton, Richard A.; Keeling, Ralph F.; Alin, Simone; Andrews, Oliver D.; Anthoni, Peter; Barbero, Leticia; Bopp, Laurent; Chevallier, Frédéric; Chini, Louise P.; Ciais, Philippe; Currie, Kim; Delire, Christine; Doney, Scott C.; Friedlingstein, Pierre; Gkritzalis, Thanos; Harris, Ian; Hauck, Judith; Haverd, Vanessa; Hoppema, Mario; Klein Goldewijk, Kees; Jain, Atul K.; Kato, Etsushi; Körtzinger, Arne; Landschützer, Peter; Lefèvre, Nathalie; Lenton, Andrew; Lienert, Sebastian; Lombardozzi, Danica; Melton, Joe R.; Metzl, Nicolas; Millero, Frank; Monteiro, Pedro M.S.; Munro, David R.; Nabel, Julia E.M.S.; Nakaoka, S.; O'Brien, Kevin; Olsen, Are; Omar, Abdirahman M.; Ono, Tsuneo; Pierrot, Denis; Poulter, Benjamin; Rödenbeck, Christian; Salisbury, Joe; Schuster, Ute; Schwinger, Jörg; Séférian, Roland; Skjelvan, Ingunn; Stocker, Benjamin D.; Sutton, Adrienne J.; Takahashi, Taro; Tian, Hanqin; Tilbrook, Bronte; Laan-Luijkx, van der Ingrid T.; Werf, van der Guido R.; Viovy, Nicolas; Walker, Anthony P.; Wiltshire, Andrew J.; Zaehle, Sönke

    2016-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project futur

  7. Global Carbon Budget 2016

    NARCIS (Netherlands)

    Le Quéré, C.; Andrew, R. M.; Canadell, J. G.; Sitch, S.; Korsbakken, J. I.; Peters, G. P.; Manning, A. C.; Boden, T. A.; Tans, P. P.; Houghton, R. A.; Keeling, R. F.; Alin, S.; Andrews, O. D.; Anthoni, P.; Barbero, L.; Bopp, L.; Chevallier, F.; Chini, L. P.; Ciais, P.; Currie, K.; Delire, C.; Doney, S. C.; Friedlingstein, P.; Gkritzalis, T.; Harris, I.; Hauck, J.; Haverd, V.; Hoppema, M.; Klein Goldewijk, K.; Jain, A. K.; Kato, E.; Körtzinger, A.; Landschützer, P.; Lefèvre, N.; Lenton, A.; Lienert, S.; Lombardozzi, D.; Melton, J. R.; Metzl, N.; Millero, F.; Monteiro, P. M. S.; Munro, D. R.; Nabel, J. E. M. S.; Nakaoka, S.-I.; O'Brien, K.; Olsen, A.; Omar, A. M.; Ono, T.; Pierrot, D.; Poulter, B.; Rödenbeck, C.; Salisbury, J.; Schuster, U.; Schwinger, J.; Séférian, R.; Skjelvan, I.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tian, H.; Tilbrook, B.; van der Laan-Luijkx, I. T.; van der Werf, G. R.; Viovy, N.; Walker, A. P.; Wiltshire, A. J.; Zaehle, S.

    2016-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project futur

  8. Global carbon budget 2014

    NARCIS (Netherlands)

    Quéré, Le C.; Peters, W.; Moriarty, R.; Friedlingstein, P.

    2015-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we descr

  9. Global Carbon Budget 2015

    NARCIS (Netherlands)

    Le Quéré, C.; Moriarty, R.; Andrew, R. M.; Canadell, J. G.; Sitch, S.; Korsbakken, J. I.; Friedlingstein, P.; Peters, G. P.; Andres, R. J.; Boden, T. A.; Houghton, R. A.; House, J. I.; Keeling, R. F.; Tans, P.; Arneth, A.; Bakker, D. C. E.; Barbero, L.; Bopp, L.; Chang, J.; Chevallier, F.; Chini, L. P.; Ciais, P.; Fader, M.; Feely, R. A.; Gkritzalis, T.; Harris, I.; Hauck, J.; Ilyina, T.; Jain, A. K.; Kato, E.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landschützer, P.; Lauvset, S. K.; Lefèvre, N.; Lenton, A.; Lima, I. D.; Metzl, N.; Millero, F.; Munro, D. R.; Murata, A.; Nabel, J. E. M. S.; Nakaoka, S.; Nojiri, Y.; O'Brien, K.; Olsen, A.; Ono, T.; Pérez, F. F.; Pfeil, B.; Pierrot, D.; Poulter, B.; Rehder, G.; Rödenbeck, C.; Saito, S.; Schuster, U.; Schwinger, J.; Séférian, R.; Steinhoff, T.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tilbrook, B.; van der Laan-Luijkx, I. T.; van der Werf, G. R.; van Heuven, S.; Vandemark, D.; Viovy, N.; Wiltshire, A.; Zaehle, S.; Zeng, N.

    2015-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we descr

  10. Global carbon budget 2014

    NARCIS (Netherlands)

    Le Quéré, C.; Moriarty, R.; Andrew, R. M.; Peters, G. P.; Ciais, P.; Friedlingstein, P.; Jones, S. D.; Sitch, S.; Tans, P.; Arneth, A.; Boden, T. A.; Bopp, L.; Bozec, Y.; Canadell, J. G.; Chevallier, F.; Cosca, C. E.; Harris, I.; Hoppema, M.; Houghton, R. A.; House, J. I.; Jain, A.; Johannessen, T.; Kato, E.; Keeling, R. F.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landa, C. S.; Landschützer, P.; Lenton, A.; Lima, I. D.; Marland, G.; Mathis, J. T.; Metzl, N.; Nojiri, Y.; Olsen, A.; Ono, T.; Peters, W.; Pfeil, B.; Poulter, B.; Raupach, M. R.; Regnier, P.; Rödenbeck, C.; Saito, S.; Salisbury, J. E.; Schuster, U.; Schwinger, J.; Séférian, R.; Segschneider, J.; Steinhoff, T.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tilbrook, B.; van der Werf, G. R.; Viovy, N.; Wang, Y.-P.; Wanninkhof, R.; Wiltshire, A.; Zeng, N.

    2014-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we descr

  11. Global carbon budget 2014

    NARCIS (Netherlands)

    Quéré, Le C.; Peters, W.; Moriarty, R.; Friedlingstein, P.

    2015-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we descr

  12. Global carbon budget 2013

    NARCIS (Netherlands)

    Le Quéré, C.; Peters, G. P.; Andres, R. J.; Andrew, R. M.; Boden, T. A.; Ciais, P.; Friedlingstein, P.; Houghton, R. A.; Marland, G.; Moriarty, R.; Sitch, S.; Tans, P.; Arneth, A.; Arvanitis, A.; Bakker, D. C E; Bopp, L.; Canadell, J. G.; Chini, L. P.; Doney, S. C.; Harper, A.; Harris, I.; House, J. I.; Jain, A. K.; Jones, S. D.; Kato, E.; Keeling, R. F.; Klein Goldewijk, Kees; Körtzinger, A.; Koven, C.; Lefèvre, N.; Maignan, F.; Omar, A.; Ono, T.; Park, G. H.; Pfeil, B.; Poulter, B.; Raupach, M. R.; Regnier, P.; Rödenbeck, C.; Saito, S.; Schwinger, J.; Segschneider, J.; Stocker, B. D.; Takahashi, T.; Tilbrook, B.; Van Heuven, S.; Viovy, N.; Wanninkhof, R.; Wiltshire, A.; Zaehle, S.

    2014-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we descr

  13. Global carbon budget 2014

    NARCIS (Netherlands)

    Le Quéré, C.; Moriarty, R.; Andrew, R. M.; Peters, G. P.; Ciais, P.; Friedlingstein, P.; Jones, S. D.; Sitch, S.; Tans, P.; Arneth, A.; Boden, T. A.; Bopp, L.; Bozec, Y.; Canadell, J. G.; Chevallier, F.; Cosca, C. E.; Harris, I.; Hoppema, M.; Houghton, R. A.; House, J. I.; Jain, A.; Johannessen, T.; Kato, E.; Keeling, R. F.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landa, C. S.; Landschützer, P.; Lenton, A.; Lima, I. D.; Marland, G.; Mathis, J. T.; Metzl, N.; Nojiri, Y.; Olsen, A.; Ono, T.; Peters, W.; Pfeil, B.; Poulter, B.; Raupach, M. R.; Regnier, P.; Rödenbeck, C.; Saito, S.; Salisbury, J. E.; Schuster, U.; Schwinger, J.; Séférian, R.; Segschneider, J.; Steinhoff, T.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tilbrook, B.; van der Werf, G. R.; Viovy, N.; Wang, Y.-P.; Wanninkhof, R.; Wiltshire, A.; Zeng, N.

    2014-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we descr

  14. Global Carbon Budget 2015

    NARCIS (Netherlands)

    Quéré, Le C.; Moriarty, R.; Andrew, R.M.; Canadell, J.G.; Sitch, S.; Korsbakken, J.I.; Friedlingstein, P.; Peters, G.P.; Andres, R.J.; Boden, T.A.; Houghton, R.A.; House, J.I.; Keeling, R.F.; Tans, P.; Arneth, A.; Bakker, D.C.E.; Barbero, L.; Bopp, L.; Chang, J.; Chevallier, F.; Chini, L.P.; Ciais, P.; Fader, M.; Feely, R.A.; Gkritzalis, T.; Harris, I.; Hauck, J.; Ilyina, T.; Jain, A.K.; Kato, E.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landschützer, P.; Lauvset, S.K.; Lefèvre, N.; Lenton, A.; Lima, I.D.; Metzl, N.; Millero, F.; Munro, D.R.; Murata, A.; Nabel, J.E.M.S.; Nakaoka, S.; Nojiri, Y.; O'Brien, K.; Olsen, A.; Ono, T.; Pérez, F.F.; Pfeil, B.; Pierrot, D.; Poulter, B.; Rehder, G.; Rödenbeck, C.; Saito, S.; Schuster, U.; Schwinger, J.; Séférian, R.; Steinhoff, T.; Stocker, B.D.; Sutton, A.J.; Takahashi, T.; Tilbrook, B.; Laan-Luijkx, Van Der I.T.; Werf, Van Der G.R.; Heuven, Van S.; Vandemark, D.; Viovy, N.; Wiltshire, A.; Zaehle, S.; Zeng, N.

    2015-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we de

  15. Global carbon budget 2013

    NARCIS (Netherlands)

    Le Quéré, C.; Peters, G. P.; Andres, R. J.; Andrew, R. M.; Boden, T. A.; Ciais, P.; Friedlingstein, P.; Houghton, R. A.; Marland, G.; Moriarty, R.; Sitch, S.; Tans, P.; Arneth, A.; Arvanitis, A.; Bakker, D. C E; Bopp, L.; Canadell, J. G.; Chini, L. P.; Doney, S. C.; Harper, A.; Harris, I.; House, J. I.; Jain, A. K.; Jones, S. D.; Kato, E.; Keeling, R. F.; Klein Goldewijk, Kees; Körtzinger, A.; Koven, C.; Lefèvre, N.; Maignan, F.; Omar, A.; Ono, T.; Park, G. H.; Pfeil, B.; Poulter, B.; Raupach, M. R.; Regnier, Piere; Rödenbeck, C.; Saito, S.; Schwinger, J.; Segschneider, J.; Stocker, B. D.; Takahashi, T.; Tilbrook, B.; Van Heuven, S.; Viovy, N.; Wanninkhof, R.; Wiltshire, A.; Zaehle, S.

    2014-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we descr

  16. Global Carbon Budget 2015

    NARCIS (Netherlands)

    Le Quéré, C.; Moriarty, R.; Andrew, R. M.; Canadell, J. G.; Sitch, S.; Korsbakken, J. I.; Friedlingstein, P.; Peters, G. P.; Andres, R. J.; Boden, T. A.; Houghton, R. A.; House, J. I.; Keeling, R. F.; Tans, P.; Arneth, A.; Bakker, D. C. E.; Barbero, L.; Bopp, L.; Chang, J.; Chevallier, F.; Chini, L. P.; Ciais, P.; Fader, M.; Feely, R. A.; Gkritzalis, T.; Harris, I.; Hauck, J.; Ilyina, T.; Jain, A. K.; Kato, E.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landschützer, P.; Lauvset, S. K.; Lefèvre, N.; Lenton, A.; Lima, I. D.; Metzl, N.; Millero, F.; Munro, D. R.; Murata, A.; Nabel, J. E. M. S.; Nakaoka, S.; Nojiri, Y.; O'Brien, K.; Olsen, A.; Ono, T.; Pérez, F. F.; Pfeil, B.; Pierrot, D.; Poulter, B.; Rehder, G.; Rödenbeck, C.; Saito, S.; Schuster, U.; Schwinger, J.; Séférian, R.; Steinhoff, T.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tilbrook, B.; van der Laan-Luijkx, I. T.; van der Werf, G. R.; van Heuven, S.; Vandemark, D.; Viovy, N.; Wiltshire, A.; Zaehle, S.; Zeng, N.

    2015-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we descr

  17. Global Carbon Budget 2015

    NARCIS (Netherlands)

    Le Quere, C.; Moriarty, R.; Andrew, R.M.; Canadell, J.G.; Sitch, S.; Korsbakken, J.I.; Friedlingstein, P.; Peters, G.P.; Andres, R.J.; Boden, T.A.; Houghton, R.A.; House, J.I.; Keeling, R.F.; Tans, P.; Arneth, A.; Bakker, D.C.E.; Barbero, L.; Bopp, L.; Chang, J.; Chevalier, F.; Chini, L.P.; Ciais, P.; Fader, M.; Feely, R.A.; Gkritzalis, T.; Harris, I.; Hauck, J.; Ilyina, T.; Jain, A.K.; Kato, E.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landschützer, P.; Lauvset, S.K.; Lefèvre, N.; Lenton, A.; Lima, I.D.; Metzl, N.; Millero, F.; Munro, D.R.; Murata, A.; Nabel, J.E.M.S.; Nakaoka, S.; Nojiri, Y.; O'Brien, K.; Olsen, A.; Ono, T.; Pérez, F.F.; Pfeil, B.; Pierrot, D.; Poulter, B.; Rehder, G.; Rödenbeck, C.; Saito, S.; Schuster, U.; Schwinger, J.; Séférian, R.; Steinhoff, T.; Stocker, B.D.; Sutton, A.J.; Takahashi, T.; Tilbrook, B.; van der Laan-Luijkx, I.T.; van der Werf, G.R.; van Heuven, S.; Vandemark, D.; Viovy, N.; Wiltshire, A.; Zaehle, S.; Zeng, N.

    2015-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we

  18. Global carbon budget 2014

    NARCIS (Netherlands)

    Le Quéré, C.; Moriarty, R.; Andrew, R. M.; Peters, G. P.; Ciais, P.; Friedlingstein, P.; Jones, S. D.; Sitch, S.; Tans, P.; Arneth, A.; Boden, T. A.; Bopp, L.; Bozec, Y.; Canadell, J. G.; Chevallier, F.; Cosca, C. E.; Harris, I.; Hoppema, M.; Houghton, R. A.; House, J. I.; Jain, A.; Johannessen, T.; Kato, E.; Keeling, R. F.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landa, C. S.; Landschützer, P.; Lenton, A.; Lima, I. D.; Marland, G.; Mathis, J. T.; Metzl, N.; Nojiri, Y.; Olsen, A.; Ono, T.; Peters, W.; Pfeil, B.; Poulter, B.; Raupach, M. R.; Regnier, P.; Rödenbeck, C.; Saito, S.; Salisbury, J. E.; Schuster, U.; Schwinger, J.; Séférian, R.; Segschneider, J.; Steinhoff, T.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tilbrook, B.; van der Werf, G. R.; Viovy, N.; Wang, Y.-P.; Wanninkhof, R.; Wiltshire, A.; Zeng, N.

    2015-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO2)emissions and their redistribution among the atmosphere, ocean, andterrestrial biosphere is important to better understand the globalcarbon cycle, support the development of climate policies, and projectfuture climate change. Here we describe

  19. The Australian terrestrial carbon budget

    Directory of Open Access Journals (Sweden)

    V. Haverd

    2012-09-01

    Full Text Available This paper reports a study of the full carbon (C-CO2 budget of the Australian continent, focussing on 1990–2011 in the context of estimates over two centuries. The work is a contribution to the RECCAP (REgional Carbon Cycle Assessment and Processes project, as one of numerous regional studies being synthesised in RECCAP. In constructing the budget, we estimate the following component carbon fluxes: Net Primary Production (NPP; Net Ecosystem Production (NEP; fire; Land Use Change (LUC; riverine export; dust export; harvest (wood, crop and livestock and fossil fuel emissions (both territorial and non-territorial.

    The mean NEP reveals that climate variability and rising CO2 contributed 12 ± 29 (1σ error on mean and 68 ± 35 Tg C yr−1 respectively. However these gains were partially offset by fire and LUC (along with other minor fluxes, which caused net losses of 31 ± 5 Tg C yr−1 and 18 ± 7 Tg C yr−1 respectively. The resultant Net Biome Production (NBP of 31 ± 35 Tg C yr−1 offset fossil fuel emissions (95 ± 6 Tg C yr−1 by 32 ± 36%. The interannual variability (IAV in the Australian carbon budget exceeds Australia's total carbon emissions by fossil fuel combustion and is dominated by IAV in NEP. Territorial fossil fuel emissions are significantly smaller than the rapidly growing fossil fuel exports: in 2009–2010, Australia exported 2.5 times more carbon in fossil fuels than it emitted by burning fossil fuels.

  20. Carbon fate in a large temperate human-impacted river system: Focus on benthic dynamics

    Science.gov (United States)

    Vilmin, Lauriane; Flipo, Nicolas; Escoffier, Nicolas; Rocher, Vincent; Groleau, Alexis

    2016-07-01

    Fluvial networks play an important role in regional and global carbon (C) budgets. The Seine River, from the Paris urban area to the entrance of its estuary (220 km), is studied here as an example of a large human-impacted river system subject to temperate climatic conditions. We assess organic C (OC) budgets upstream and downstream from one of the world's largest wastewater treatment plants and for different hydrological conditions using a hydrobiogeochemical model. The fine representation of sediment accumulation on the river bed allows for the quantification of pelagic and benthic effects on OC export toward the estuary and on river metabolism (i.e., net CO2 production). OC export is significantly affected by benthic dynamics during the driest periods, when 25% of the inputs to the system is transformed or stored in the sediment layer. Benthic processes also substantially affect river metabolism under any hydrological condition. On average, benthic respiration accounts for one third of the total river respiration along the studied stretch (0.27 out of 0.86 g C m-2 d-1). Even though the importance of benthic processes was already acknowledged by the scientific community for headwater streams, these results stress the major influence of benthic dynamics, and thus of physical processes such as sedimentation and resuspension, on C cycling in downstream river systems. It opens the door to new developments in the quantification of C emissions by global models, whereby biogeochemical processing and benthic dynamics should be taken into account.

  1. The Australian terrestrial carbon budget

    Directory of Open Access Journals (Sweden)

    V. Haverd

    2013-02-01

    Full Text Available This paper reports a study of the full carbon (C-CO2 budget of the Australian continent, focussing on 1990–2011 in the context of estimates over two centuries. The work is a contribution to the RECCAP (REgional Carbon Cycle Assessment and Processes project, as one of numerous regional studies. In constructing the budget, we estimate the following component carbon fluxes: net primary production (NPP; net ecosystem production (NEP; fire; land use change (LUC; riverine export; dust export; harvest (wood, crop and livestock and fossil fuel emissions (both territorial and non-territorial. Major biospheric fluxes were derived using BIOS2 (Haverd et al., 2012, a fine-spatial-resolution (0.05° offline modelling environment in which predictions of CABLE (Wang et al., 2011, a sophisticated land surface model with carbon cycle, are constrained by multiple observation types. The mean NEP reveals that climate variability and rising CO2 contributed 12 ± 24 (1σ error on mean and 68 ± 15 TgC yr−1, respectively. However these gains were partially offset by fire and LUC (along with other minor fluxes, which caused net losses of 26 ± 4 TgC yr−1 and 18 ± 7 TgC yr−1, respectively. The resultant net biome production (NBP is 36 ± 29 TgC yr−1, in which the largest contributions to uncertainty are NEP, fire and LUC. This NBP offset fossil fuel emissions (95 ± 6 TgC yr−1 by 38 ± 30%. The interannual variability (IAV in the Australian carbon budget exceeds Australia's total carbon emissions by fossil fuel combustion and is dominated by IAV in NEP. Territorial fossil fuel emissions are significantly smaller than the rapidly growing fossil fuel exports: in 2009–2010, Australia exported 2.5 times more carbon in fossil fuels than it emitted by burning fossil fuels.

  2. Benthic primary production budget of a Caribbean reef lagoon (Puerto Morelos, Mexico.

    Directory of Open Access Journals (Sweden)

    Malik S Naumann

    Full Text Available High photosynthetic benthic primary production (P represents a key ecosystem service provided by tropical coral reef systems. However, benthic P budgets of specific ecosystem compartments such as macrophyte-dominated reef lagoons are still scarce. To address this, we quantified individual and lagoon-wide net (Pn and gross (Pg primary production by all dominant functional groups of benthic primary producers in a typical macrophyte-dominated Caribbean reef lagoon near Puerto Morelos (Mexico via measurement of O₂ fluxes in incubation experiments. The photosynthetically active 3D lagoon surface area was quantified using conversion factors to allow extrapolation to lagoon-wide P budgets. Findings revealed that lagoon 2D benthic cover was primarily composed of sand-associated microphytobenthos (40%, seagrasses (29% and macroalgae (27%, while seagrasses dominated the lagoon 3D surface area (84%. Individual Pg was highest for macroalgae and scleractinian corals (87 and 86 mmol O₂ m(-2 specimen area d(-1, respectively, however seagrasses contributed highest (59% to the lagoon-wide Pg. Macroalgae exhibited highest individual Pn rates, but seagrasses generated the largest fraction (51% of lagoon-wide Pn. Individual R was highest for scleractinian corals and macroalgae, whereas seagrasses again provided the major lagoon-wide share (68%. These findings characterise the investigated lagoon as a net autotrophic coral reef ecosystem compartment revealing similar P compared to other macrophyte-dominated coastal environments such as seagrass meadows and macroalgae beds. Further, high lagoon-wide P (Pg: 488 and Pn: 181 mmol O₂ m(-2 lagoon area d(-1 and overall Pg:R (1.6 indicate substantial benthic excess production within the Puerto Morelos reef lagoon and suggest the export of newly synthesised organic matter to surrounding ecosystems.

  3. Benthic primary production budget of a Caribbean reef lagoon (Puerto Morelos, Mexico).

    Science.gov (United States)

    Naumann, Malik S; Jantzen, Carin; Haas, Andreas F; Iglesias-Prieto, Roberto; Wild, Christian

    2013-01-01

    High photosynthetic benthic primary production (P) represents a key ecosystem service provided by tropical coral reef systems. However, benthic P budgets of specific ecosystem compartments such as macrophyte-dominated reef lagoons are still scarce. To address this, we quantified individual and lagoon-wide net (Pn) and gross (Pg) primary production by all dominant functional groups of benthic primary producers in a typical macrophyte-dominated Caribbean reef lagoon near Puerto Morelos (Mexico) via measurement of O₂ fluxes in incubation experiments. The photosynthetically active 3D lagoon surface area was quantified using conversion factors to allow extrapolation to lagoon-wide P budgets. Findings revealed that lagoon 2D benthic cover was primarily composed of sand-associated microphytobenthos (40%), seagrasses (29%) and macroalgae (27%), while seagrasses dominated the lagoon 3D surface area (84%). Individual Pg was highest for macroalgae and scleractinian corals (87 and 86 mmol O₂ m(-2) specimen area d(-1), respectively), however seagrasses contributed highest (59%) to the lagoon-wide Pg. Macroalgae exhibited highest individual Pn rates, but seagrasses generated the largest fraction (51%) of lagoon-wide Pn. Individual R was highest for scleractinian corals and macroalgae, whereas seagrasses again provided the major lagoon-wide share (68%). These findings characterise the investigated lagoon as a net autotrophic coral reef ecosystem compartment revealing similar P compared to other macrophyte-dominated coastal environments such as seagrass meadows and macroalgae beds. Further, high lagoon-wide P (Pg: 488 and Pn: 181 mmol O₂ m(-2) lagoon area d(-1)) and overall Pg:R (1.6) indicate substantial benthic excess production within the Puerto Morelos reef lagoon and suggest the export of newly synthesised organic matter to surrounding ecosystems.

  4. Carbon fate in a large temperate human-impacted river system: focus on benthic dynamics

    Science.gov (United States)

    Vilmin, Lauriane; Flipo, Nicolas; Escoffier, Nicolas; Rocher, Vincent; Groleau, Alexis

    2016-04-01

    During the last decade, several studies highlighted the important role of fluvial networks in regional and global carbon (C) budgets. Therefore, for sustainable C management, in-river C processing needs to be well understood. The Seine River from the Paris urban area to the entrance of its estuary (220 km) is studied here as a pertinent example of a large human impacted river system subject to temperate climatic conditions. We assess organic C (OC) budgets up- and downstream one of the world's largest waste water treatment plants and for different hydrological conditions through hydro-biogeochemical distributed modelling. The fine representation of sediment accumulation on the river bed allows the quantification of the effect of pelagic and benthic processes on OC export towards the estuary and on river metabolism (i.e. net CO2 emission). OC export is significantly affected by benthic dynamics during the driest periods, when 25 % of the inputs to the system is transformed or stored in the sediment layer. River metabolism is also significantly affected by benthic processes, whatever the hydrological conditions. On average, benthic respiration accounts for one third of the total ecosystem respiration along the studied stretch (0.23 out of 0.86 gC.m-2.d-1). These results stress the major influence of benthic dynamics, and thus of physical processes such as sedimentation and re-suspension on C cycling, in large human-impacted temperate river systems and on C export to the estuaries. Even though the importance of benthos processes was already acknowledged by the scientific community for headwater streams, this work highlights its importance for downstream river systems and opens the door to new developments in the quantification of C emissions by global models, in which biogeochemical processing and benthic dynamics must be taken into account.

  5. Carbon budgets and energy transition pathways

    NARCIS (Netherlands)

    Van Vuuren, Detlef P.; Van Soest, Heleen; Riahi, Keywan; Clarke, Leon; Krey, Volker; Kriegler, Elmar; Rogelj, Joeri; Schaeffer, Michiel; Tavoni, Massimo

    2016-01-01

    Scenarios from integrated assessment models can provide insights into how carbon budgets relate to other policy-relevant indicators by including information on how fast and by how much emissions can be reduced. Such indicators include the peak year of global emissions, the decarbonisation rate and t

  6. Carbon budgets and energy transition pathways

    NARCIS (Netherlands)

    Vuuren, Van Detlef P.; Soest, van Heleen; Riahi, Keywan; Clarke, Leon; Krey, Volker; Kriegler, Elmar; Rogelj, Joeri; Schaeffer, Michiel; Tavoni, Massimo

    2016-01-01

    Scenarios from integrated assessment models can provide insights into how carbon budgets relate to other policy-relevant indicators by including information on how fast and by how much emissions can be reduced. Such indicators include the peak year of global emissions, the decarbonisation rate an

  7. Carbon Budget of Russian Forests

    Directory of Open Access Journals (Sweden)

    A. Z. Shvidenko

    2014-02-01

    Full Text Available Net Ecosystem Carbon Balance (NECB of Russian forests for 2007–2009 is presented based on consistent application of applied systems analysis and modern information technologies. Use of landscape-ecosystem approach resulted in the NECB at 546±120 Tg C year–1, or 66±15 g C m–2 year–1. There is a substantial difference between the NECB of European and Asian parts, as well as the clear zonal gradients within these geographical regions. While the total carbon sink is high, large forest areas, particularly on permafrost, serve as a carbon source. The ratio between net primary production and soil heterotrophic respiration, together with natural and human-induced disturbances are major drivers of the magnitude and spatial distribution of the NECB of forest ecosystems. Using the Bayesian approach, mutual constraints of results that are obtained by independent methods enable to decrease uncertainties of the final result.

  8. Benthic carbon mineralization in hadal trenches

    DEFF Research Database (Denmark)

    Wenzhöfer, F.; Oguri, K.; Middelboe, Mathias;

    2016-01-01

    consumption rates and sediment characteristics from the trench axis of two contrasting trench systems in the Pacific Ocean; the Izu-Bonin Trench underlying mesotrophic waters and the Tonga Trench underlying oligotrophic waters. In situ oxygen consumption at the Izu-Bonin Trench axis site (9200 m; 746 +/- 103...... mu mol m(-2) d(-1); n=27) was 3-times higher than at the Tonga Trench axis site (10800 m; 225 +/- 50 pmol m(-2) d(-1); n=7) presumably reflecting the higher surface water productivity in the Northern Pacific. Comparing benthic O-2 consumption rates measured in the central hadal Tonga Trench...

  9. Studies on carbon budget score remarkable progress

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ On 23 November, 2006, a key CAS research project on carbon budget passed the review by a panel of experts under the joint auspices of the CAS Bureau of Comprehensive Planning and the CAS Bureau of Science and Technology for Resourc es and Environment. The panel was made up of 11 prestigious experts, led by CHEN Yiyu, a CAS Member and President of National Natural Sciences Foundation of China.

  10. Alterations in the energy budget of Arctic benthic species exposed to oil-related compounds

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Gro Harlaug [Akvaplan-niva, Polar Environmental Center, N-9296 Tromso (Norway) and Norwegian College of Fishery Science, University of Tromso, N-9037 Tromso (Norway)]. E-mail: gho@akvaplan.niva.noph; Sva, Eirin [Akvaplan-niva, Polar Environmental Center, N-9296 Tromso (Norway); Carroll, JoLynn [Akvaplan-niva, Polar Environmental Center, N-9296 Tromso (Norway); Camus, Lionel [Akvaplan-niva, Polar Environmental Center, N-9296 Tromso (Norway); De Coen, Wim [Laboratory for Ecophysiology, Biochemistry and Toxicology, University of Antwerp (UA), Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Smolders, Roel [Laboratory for Ecophysiology, Biochemistry and Toxicology, University of Antwerp (UA), Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Environmental Toxicology, VITO, Boeretang 200, B-2400 Mol (Belgium); Overaas, Helene [Norwegian Institute for Water Research (NIVA), CIENS, Gaustadalleen, N-0316 Oslo (Norway); Multiconsult AS, Hoffsveien 1, N-0275 Oslo (Norway); Hylland, Ketil [Norwegian Institute for Water Research (NIVA), CIENS, Gaustadalleen, N-0316 Oslo (Norway); Department of Biology, University of Oslo, P.O. Box 1066, Blindern, N-0316 Oslo (Norway)

    2007-06-15

    We studied cellular energy allocation (CEA) in three Arctic benthic species (Gammarus setosus (Amphipoda), Onisimus litoralis (Amphipoda), and Liocyma fluctuosa (Bivalvia)) exposed to oil-related compounds. The CEA biomarker measures the energy budget of organisms by biochemically assessing changes in energy available (carbohydrates, protein and lipid content) and the integrated energy consumption (electron transport system activity (ETS) as the cellular aspect of respiration). Energy budget was measured in organisms subjected to water-accommodated fraction (WAF) of crude oil and drill cuttings (DC) to evaluate whether these compounds affect the energy metabolism of the test species. We observed significantly lower CEA values and higher ETS activity in G. setosus subjected to WAF treatment compared to controls (p {<=} 0.03). Higher CEA value and lower cellular respiration were observed in O. litoralis exposed to DC compared to controls (p = 0.02). No difference in the energy budget of L. fluctuosa was observed between the treatments (p {>=} 0.19). Different responses to oil-related compounds between the three test species are likely the result of differences in feeding and burrowing behavior and species-specific sensitivity to petroleum-related compounds.

  11. Tropical deforestation and the global carbon budget

    Energy Technology Data Exchange (ETDEWEB)

    Melillo, J.M.; Kicklighter, D.W. [Ecosystems Center, Woods Hole, MA (United States). Marine Biological Lab.; Houghton, R.A. [Woods Hole Research Center, MA (United States); McGuire, A.D. [Univ. of Alaska, Fairbanks, AK (United States)

    1996-12-31

    The CO{sub 2} concentration of the atmosphere has increased by almost 30% since 1800. This increase is due largely to two factors: the combustion of fossil fuel and deforestation to create croplands and pastures. Deforestation results in a net flux of carbon to the atmospheric because forests contain 20--50 times more carbon per unit area than agricultural lands. In recent decades, the tropics have been the primary region of deforestation.The annual rate of CO{sub 2} released due to tropical deforestation during the early 1990s has been estimated at between 1.2 and 2.3 gigatons C. The range represents uncertainties about both the rates of deforestation and the amounts of carbon stored in different types of tropical forests at the time of cutting. An evaluation of the role of tropical regions in the global carbon budget must include both the carbon flux to the atmosphere due to deforestation and carbon accumulation, if any, in intact forests. In the early 1990s, the release of CO{sub 2} from tropical deforestation appears to have been mostly offset by CO{sub 2} uptake occurring elsewhere in the tropics, according to an analysis of recent trends in the atmospheric concentrations of O{sub 2} and N{sub 2}. Interannual variations in climate and/or CO{sub 2} fertilization may have been responsible for the CO{sub 2} uptake in intact forests. These mechanisms are consistent with site-specific measurements of net carbon fluxes between tropical forests and the atmosphere, and with regional and global simulations using process-based biogeochemistry models. 86 refs., 1 fig., 6 tabs.

  12. The global carbon budget 1959–2011

    Directory of Open Access Journals (Sweden)

    C. Le Quéré

    2012-12-01

    Full Text Available Accurate assessment of anthropogenic carbon dioxide (CO2 emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the climate policy process, and project future climate change. Present-day analysis requires the combination of a range of data, algorithms, statistics and model estimates and their interpretation by a broad scientific community. Here we describe datasets and a methodology developed by the global carbon cycle science community to quantify all major components of the global carbon budget, including their uncertainties. We discuss changes compared to previous estimates, consistency within and among components, and methodology and data limitations. Based on energy statistics, we estimate that the global emissions of CO2 from fossil fuel combustion and cement production were 9.5 ± 0.5 PgC yr−1 in 2011, 3.0 percent above 2010 levels. We project these emissions will increase by 2.6% (1.9–3.5% in 2012 based on projections of Gross World Product and recent changes in the carbon intensity of the economy. Global net CO2 emissions from Land-Use Change, including deforestation, are more difficult to update annually because of data availability, but combined evidence from land cover change data, fire activity in regions undergoing deforestation and models suggests those net emissions were 0.9 ± 0.5 PgC yr−1 in 2011. The global atmospheric CO2 concentration is measured directly and reached 391.38 ± 0.13 ppm at the end of year 2011, increasing 1.70 ± 0.09 ppm yr−1 or 3.6 ± 0.2 PgC yr−1 in 2011. Estimates from four ocean models suggest that the ocean CO2 sink was 2.6 ± 0.5 PgC yr−1 in 2011, implying a global residual terrestrial CO2 sink of 4.1 ± 0.9 PgC yr−1. All uncertainties are reported as ±1

  13. The global carbon budget 1959–2011

    Directory of Open Access Journals (Sweden)

    C. Le Quéré

    2013-05-01

    Full Text Available Accurate assessments of anthropogenic carbon dioxide (CO2 emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the climate policy process, and project future climate change. Present-day analysis requires the combination of a range of data, algorithms, statistics and model estimates and their interpretation by a broad scientific community. Here we describe datasets and a methodology developed by the global carbon cycle science community to quantify all major components of the global carbon budget, including their uncertainties. We discuss changes compared to previous estimates, consistency within and among components, and methodology and data limitations. CO2 emissions from fossil fuel combustion and cement production (EFF are based on energy statistics, while emissions from Land-Use Change (ELUC, including deforestation, are based on combined evidence from land cover change data, fire activity in regions undergoing deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM is computed from the concentration. The mean ocean CO2 sink (SOCEAN is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. Finally, the global residual terrestrial CO2 sink (SLAND is estimated by the difference of the other terms. For the last decade available (2002–2011, EFF was 8.3 ± 0.4 PgC yr−1, ELUC 1.0 ± 0.5 PgC yr−1, GATM 4.3 ± 0.1PgC yr−1, SOCEAN 2.5 ± 0.5 PgC yr−1, and SLAND 2.6 ± 0.8 PgC yr−1. For year 2011 alone, EFF was 9.5 ± 0.5 PgC yr−1, 3.0 percent above 2010, reflecting a continued trend in these emissions; ELUC was 0.9 ± 0.5 PgC yr−1, approximately constant throughout the decade; GATM was 3.6 ± 0.2 PgC yr−1, SOCEAN was 2.7 ± 0.5 PgC yr−1, and SLAND was 4.1 ± 0.9 PgC yr−1. GATM was low in 2011

  14. Benthic biogeochemical cycling, nutrient stoichiometry, and carbon and nitrogen mass balances in a eutrophic freshwater bay

    Science.gov (United States)

    Klump, J.V.; Fitzgerald, S.A.; Waplesa, J.T.

    2009-01-01

    Green Bay, while representing only ,7% of the surface area and ??1.4% of the volume of Lake Michigan, contains one-third of the watershed of the lake, and receives approximately one-third of the total nutrient loading to the Lake Michigan basin, largely from the Fox River at the southern end of the bay. With a history of eutrophic conditions dating back nearly a century, the southern portion of the bay behaves as an efficient nutrient and sediment trap, sequestering much of the annual carbon and nitrogen input within sediments accumulating at up to 1 cm per year. Depositional fluxes of organic matter varied from ??0.1 mol C m-2 yr-1 to >10 mol C m-2 yr-1 and were both fairly uniform in stoichiometric composition and relatively labile. Estimates of benthic recycling derived from pore-water concentration gradients, whole-sediment incubation experiments, and deposition-burial models of early diagenesis yielded an estimated 40% of the carbon and 50% of the nitrogen recycled back into the overlying water. Remineralization was relatively rapid with ??50% of the carbon remineralized within <15 yr of deposition, and a mean residence time for metabolizable carbon and nitrogen in the sediments of 20 yr. On average, organic carbon regeneration occurred as 75% CO2, 15% CH4, and 10% dissolved organic carbon (DOC). Carbon and nitrogen budgets for the southern bay were based upon direct measurements of inputs and burial and upon estimates of export and production derived stoichiometrically from a coupled phosphorus budget. Loadings of organic carbon from rivers were ??3.7 mol m-2 yr-1, 80% in the form of DOC and 20% as particulate organic carbon. These inputs were lost through export to northern Green Bay and Lake Michigan (39%), through sediment burial (26%), and net CO2 release to the atmosphere (35%). Total carbon input, including new production, was 4.54 mol m-2 C yr-1, equivalent to ??10% of the gross annual primary production. Nitrogen budget terms were less well quantified

  15. A preliminary carbon budget for two oligotrophic hardwater lakes in the Forsmark area, Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Eva [Uppsala Univ. (Sweden). Dept. of Limnology

    2001-06-01

    The Swedish Nuclear Fuel and Waste Management Co (SKB) is responsible for management and disposal of Swedish radioactive waste. The company is planning to construct repositories that will keep radioactive waste away from humans for hundreds of thousands of years. In a safety assessment of the repositories hypothetical releases are used to evaluate the robustness of the repositories. It is important to know how the radioactive nuclides would react if they were released and by which way they could enter the living biota. SFR are responsible for the disposal of low radioactive waste and close to the nuclear plant in Forsmark there is a storage for low radioactive waste. At the moment this storage is located in the bedrock far below the sea level but due to land-rise in the area it will in the future be located above sea level. Hence, it is of importance to know how the surface ecosystems in the area are functioning. A carbon budget for the aquatic ecosystem above SFR in Oeresundsgrepen exist, but it is also important to have a carbon budget for the surface systems in the Forsmark area since SFR in the future will be situated above sea level. Carbon budgets can be used to get a picture of how an ecosystem functions. The carbon flow shows how carbon is transported through a food web from lower trophic levels, e.g. plants and bacteria to higher trophic levels such as fish. Oligotrophic hardwater lakes are the most important lakes in the Forsmark area. This report aims to give a picture of a potential flow of carbon through the ecosystem in two oligotrophic hard-water lakes, Lake Haellefjaerd and Lake Eckarfjaerden. Macrophyte, mainly Chara, were calculated to make up the largest part of the biomass and production in both lakes. Benthic bacteria and microphytobenthos (benthic photosynthesising microorganisms) were other large contributors to the production. Benthic bacteria were found responsible for a major part of respiration and, hence, consumption of carbon in the

  16. Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya

    Directory of Open Access Journals (Sweden)

    F. Dehairs

    2004-08-01

    Full Text Available The origin of carbon substrates used by in situ sedimentary bacterial communities was investigated in an intertidal mangrove ecosystem and in adjacent seagrass beds in Gazi bay (Kenya by δ13C analysis of bacteria-specific PLFA (phospholipid fatty acids and bulk organic carbon. Export of mangrove-derived organic matter to the adjacent seagrass-covered bay was evident from sedimentary total organic carbon (TOC and δ13CTOC data. PLFA δ13C data indicate that the substrate used by bacterial communities varied strongly and that exported mangrove carbon was a significant source for bacteria in the adjacent seagrass beds. Within the intertidal mangrove forest, bacterial PLFA at the surface layer (0-1 cm typically showed more enriched δ13C values than deeper (up to 10 cm sediment layers, suggesting a contribution from microphytobenthos and/or inwelled seagrass material. Under the assumption that seagrasses and mangroves are the dominant potential end-members, the estimated contribution of mangrove-derived carbon to benthic mineralization in the seagrass beds (16-74% corresponds fairly well to the estimated contribution of mangrove C to the sedimentary organic matter pool (21-71% across different seagrass sites. Based on these results and a compilation of literature data, we suggest that allochtonous carbon trapped in seagrass beds may often represent a significant fraction of the substrate for benthic mineralization - both in cases where seagrass C dominates the sediment TOC pool and in cases where external inputs are significant. Hence, it is likely that community respiration data systematically overestimate the role of mineralization in the overall seagrass C budget.

  17. Eutrophication in the northern Adriatic Sea: Benthic fluxes and nutrient budgets

    Energy Technology Data Exchange (ETDEWEB)

    Berelson, W.M.; Hammond, D.E. (Univ. of Southern California, Los Angeles (United States)); Giordani, P. (Inst. di Geologia Marina-CNR, Bologna (Italy))

    1990-01-09

    The northern Adriatic Sea has been plagued by problems of eutrophication. This area is relatively shallow (maximum depth = 60m), becoming stratified during the summer months which inhibits oxygen transport to bottom waters. Anthropogenic nutrient loading in rivers entering the northern Adriatic has increased nutrient input to this system and stimulated algai growth. Five stations in the western Adriatic (south of the Po River Delta) were occupied during September, 1988 and benthic flux chambers used to measure nutrient fluxes. These sites included 3 stations previously studied in 1982. Flux measurements of dissolved silica, nitrate, oxygen, ammonia, phosphate, CO[sub 2], alkalinity and radon were made during 24 hour incubations of flux chambers (area covered - 0.07 m[sup 2], volume = [approximately]81) that were continuously stirred and sampled periodically. Nutrient fluxes measured were generally consistent with the fluxes measured previously in June, 1982 except for radon fluxes which were 203 times greater in the earlier field season. There was a general trend in nutrient fluxes to decrease offshore, a pattern probably controlled by the sedimentation patterns because fine grained, organic matter-rich sediment are concentrated in a zone near shore. Average regional fluxes were (in mmol m[sup -2]d[sup -1], negative values indicate flux into sediment): Oxygen (-12), CO[sub 2] (19), Alkalinity (4), Silica (3.3), Ammonia (1.5), Phosphate (0.1) and Nitrate (0.3). The carbon/ammonia flux ratio is about twice the C/N ratio in marine phytoplankton, suggesting that large amounts of denitrification may be occuring in these sediments. Comparisons of benthic fluxes and sediment burial rates indicate that 50-90% of the carbon, silica, phosphorus and nitrogen arriving at the sediment-water interface is recycled before burial. The nutrient input to the water column from NW Adriatic sediments is about equal to the input from coastal rivers.

  18. Incorporating benthic community changes into hydrochemical-based projections of coral reef calcium carbonate production under ocean acidification

    Science.gov (United States)

    Shaw, Emily C.; Hamylton, Sarah M.; Phinn, Stuart R.

    2016-06-01

    The existence of coral reefs is dependent on the production and maintenance of calcium carbonate (CaCO3) framework that is produced through calcification. The net production of CaCO3 will likely decline in the future, from both declining net calcification rates (decreasing calcification and increasing dissolution) and shifts in benthic community composition from calcifying organisms to non-calcifying organisms. Here, we present a framework for hydrochemical studies that allows both declining net calcification rates and changes in benthic community composition to be incorporated into projections of coral reef CaCO3 production. The framework involves upscaling net calcification rates for each benthic community type using mapped proportional cover of the benthic communities. This upscaling process was applied to the reef flats at One Tree and Lady Elliot reefs (Great Barrier Reef) and Shiraho Reef (Okinawa), and compared to existing data. Future CaCO3 budgets were projected for Lady Elliot Reef, predicting a decline of 53 % from the present value by end-century (800 ppm CO2) without any changes to benthic community composition. A further 5.7 % decline in net CaCO3 production is expected for each 10 % decline in calcifier cover, and net dissolution is predicted by end-century if calcifier cover drops below 18 % of the present extent. These results show the combined negative effect of both declining net calcification rates and changing benthic community composition on reefs and the importance of considering both processes for determining future reef CaCO3 production.

  19. A carbon budget for the aquatic ecosystem above SFR in Oeregrundsgrepen

    Energy Technology Data Exchange (ETDEWEB)

    Kumblad, L [Stockholm Univ. (Sweden). Dept. of Systems Ecology

    1999-07-01

    The potential hazards of radionuclide release to humans and the environment is regularly evaluated in safety assessments of SFR, the final repository for radioactive operational waste. SFR handles, since 1988, low and intermediate level nuclear waste from Swedish nuclear power plants, medical care attendance, industries and research laboratories and is located in the bedrock 50 meters under the seabed of Oeregrundsgrepen in the southern Bothnian Sea. This report presents a description of the aquatic ecosystem and a carbon budget for the area above SFR with the aim to include ecosystem dynamics in the present safety assessment of the repository (SAFE). The carbon budget will support SAFE by facilitating evaluations of transport and fate of radionuclides, primarily {sup 14}C, in case of a release from the repository and describe the ecosystem structure and function. Furthermore, {sup 14}C is the dose-dominant radionuclide in the repository which most likely will follow the general carbon flow in the ecosystem if there should be a release. The carbon budget was based on biomass and flow of carbon between thirteen functional groups (including POC and DOC) in the ecosystem above SFR and the results indicates that the organisms are self-sufficient on carbon and that the area exports carbon corresponding to approximately 50% of the annual primary production. The largest organic carbon pool is DOC (one and a half time larger than the total biomass) and the major functional organism groups are the macrophytes (37% of the total biomass), benthic macrofauna (36%), and the microphytes (11%). The soft bottom and phytobenthic communities seem to have important roles in the ecosystem since these communities comprise the main part of the living carbon in the studied area.

  20. Carbon flows in the benthic food web at the deep-sea observatory HAUSGARTEN (Fram Strait)

    NARCIS (Netherlands)

    Van Oevelen, D.; Bergmann, M.; Soetaert, K.E.R.; Bauerfeind, E.; Hasemann, C.; Klages, M.; Schewe, I.; Soltwedel, T.; Budaeva, N.E.

    2011-01-01

    The HAUSGARTEN observatory is located in the eastern Fram Strait (Arctic Ocean) and used as long-term monitoring site to follow changes in the Arctic benthic ecosystem. Linear inverse modelling was applied to decipher carbon flows among the compartments of the benthic food web at the central

  1. Carbon flows in the benthic food web at the deep-sea observatory HAUSGARTEN (Fram Strait)

    NARCIS (Netherlands)

    Van Oevelen, D.; Bergmann, M.; Soetaert, K.E.R.; Bauerfeind, E.; Hasemann, C.; Klages, M.; Schewe, I.; Soltwedel, T.; Budaeva, N.E.

    2011-01-01

    The HAUSGARTEN observatory is located in the eastern Fram Strait (Arctic Ocean) and used as long-term monitoring site to follow changes in the Arctic benthic ecosystem. Linear inverse modelling was applied to decipher carbon flows among the compartments of the benthic food web at the central HAUSGAR

  2. Drivers and predictions of coral reef carbonate budget trajectories

    Science.gov (United States)

    Graham, Nicholas A. J.; Jennings, Simon; Perry, Chris T.

    2017-01-01

    Climate change is one of the greatest threats to the long-term maintenance of coral-dominated tropical ecosystems, and has received considerable attention over the past two decades. Coral bleaching and associated mortality events, which are predicted to become more frequent and intense, can alter the balance of different elements that are responsible for coral reef growth and maintenance. The geomorphic impacts of coral mass mortality have received relatively little attention, particularly questions concerning temporal recovery of reef carbonate production and the factors that promote resilience of reef growth potential. Here, we track the biological carbonate budgets of inner Seychelles reefs from 1994 to 2014, spanning the 1998 global bleaching event when these reefs lost more than 90% of coral cover. All 21 reefs had positive budgets in 1994, but in 2005 budgets were predominantly negative. By 2014, carbonate budgets on seven reefs were comparable with 1994, but on all reefs where an ecological regime shift to macroalgal dominance occurred, budgets remained negative through 2014. Reefs with higher massive coral cover, lower macroalgae cover and lower excavating parrotfish biomass in 1994 were more likely to have positive budgets post-bleaching. If mortality of corals from the 2016 bleaching event is as severe as that of 1998, our predictions based on past trends would suggest that six of eight reefs with positive budgets in 2014 would still have positive budgets by 2030. Our results highlight that reef accretion and framework maintenance cannot be assumed from the ecological state alone, and that managers should focus on conserving aspects of coral reefs that support resilient carbonate budgets. PMID:28123092

  3. Drivers and predictions of coral reef carbonate budget trajectories.

    Science.gov (United States)

    Januchowski-Hartley, Fraser A; Graham, Nicholas A J; Wilson, Shaun K; Jennings, Simon; Perry, Chris T

    2017-01-25

    Climate change is one of the greatest threats to the long-term maintenance of coral-dominated tropical ecosystems, and has received considerable attention over the past two decades. Coral bleaching and associated mortality events, which are predicted to become more frequent and intense, can alter the balance of different elements that are responsible for coral reef growth and maintenance. The geomorphic impacts of coral mass mortality have received relatively little attention, particularly questions concerning temporal recovery of reef carbonate production and the factors that promote resilience of reef growth potential. Here, we track the biological carbonate budgets of inner Seychelles reefs from 1994 to 2014, spanning the 1998 global bleaching event when these reefs lost more than 90% of coral cover. All 21 reefs had positive budgets in 1994, but in 2005 budgets were predominantly negative. By 2014, carbonate budgets on seven reefs were comparable with 1994, but on all reefs where an ecological regime shift to macroalgal dominance occurred, budgets remained negative through 2014. Reefs with higher massive coral cover, lower macroalgae cover and lower excavating parrotfish biomass in 1994 were more likely to have positive budgets post-bleaching. If mortality of corals from the 2016 bleaching event is as severe as that of 1998, our predictions based on past trends would suggest that six of eight reefs with positive budgets in 2014 would still have positive budgets by 2030. Our results highlight that reef accretion and framework maintenance cannot be assumed from the ecological state alone, and that managers should focus on conserving aspects of coral reefs that support resilient carbonate budgets. © 2017 The Authors.

  4. The importance of large benthic foraminifera to reef island sediment budget and dynamics at Raine Island, northern Great Barrier Reef

    Science.gov (United States)

    Dawson, John L.; Smithers, Scott G.; Hua, Quan

    2014-10-01

    Low-lying reef islands are among the most vulnerable environments on earth to anthropogenic-induced climate change and sea-level rise over the next century because they are low, composed of unconsolidated sediment that is able to be mobilised by waves and currents, and depend on sediments supplied by reef organisms that are particularly sensitive to environmental changes (e.g. ocean temperatures and chemistry). Therefore, the spatial and temporal links between active carbonate production and island formation and dynamics are fundamental to predicting future island resilience, yet remain poorly quantified. In this paper we present results of a detailed geomorphological and sedimentological study of a reef and sand cay on the northern Great Barrier Reef. We provide an empirical investigation of the temporal linkages between sediment production and reef island development using a large collection of single grain AMS 14C dates. Large benthic foraminifera (LBF) are the single most important contributor to contemporary island sand mass (47%; ranging from 36% to 63%) at Raine Island, reflecting rapid rates of sediment production and delivery. Standing stock data reveal extremely high production rates on the reef (1.8 kg m- 2 yr- 1), while AMS 14C dates of single LBF tests indicate rapid rates of sediment transferral across the reef. We also demonstrate that age is statistically related to preservation and taphonomic grade (severely abraded tests > moderately abraded tests > pristine tests). We construct a contemporary reef and island sediment budget model for Raine Island that shows that LBF (Baculogypsina, Marginopora and Amphistegina) contribute 55% of the sediment produced on the reef annually, of which a large proportion (54%) contribute to the net annual accretion of the island. The tight temporal coupling between LBF growth and island sediment supply combined with the sensitivity of LBF to bleaching and ocean acidification suggests that islands dominated by LBF are

  5. Developing Carbon Budgets for Cities: Phoenix as a Case Study

    Science.gov (United States)

    McHale, M. R.; Baker, L. A.; Koerner, B. A.; Grimm, N. B.

    2008-12-01

    Studies have shown that cities can alter regional carbon dynamics through changing ecosystem productivity, overall carbon cycling rate, and total carbon storage in vegetation and soils. Furthermore, people in urban regions import a large amount of carbon in food and fuel, as well as release an exceptional amount of CO2 into the atmosphere. Numerous studies have attempted to quantify some sources and sinks of carbon in urban areas, although a complete carbon budget for a city that accounts for total inputs, outputs, and storage within the ecosystem has yet to be fully accomplished. One challenge is associated with attaining the data necessary to accurately account for all carbon dynamics in these heterogeneous and complex ecosystems. Our goal was to estimate a budget for the Phoenix metropolitan area while developing methodology to calculate carbon dynamics in urban systems that can be applied to cities across the US. Only with comparable carbon budgets for multiple cities will we finally begin to understand the influence of urbanization on carbon dynamics. Our analysis shows when calculating certain variables like transportation emissions, results can vary radically (up to 250%) depending on the data source and methodology implemented (i.e. bottom-up vs. top-down). A common assumption is that productivity and carbon storage will increase with urbanization in arid systems due to water and nutrient inputs, as well as changes in vegetation structure; however, our results indicated that this may not actually be the case in Phoenix where a large number of residents design landscapes to conserve water. Even if all urban expansion was dedicated to landscapes designed for carbon sequestration and storage, vegetation and soils will unlikely have a large effect on the C budget without significant changes in transportation and lifestyle choices.

  6. Carbon cycling in the deep eastern North Pacific benthic food web: Investigating the effect of organic carbon input

    NARCIS (Netherlands)

    Dunlop, K.M.; Van Oevelen, D.; Ruhl, H.A.; Huffard, C.L.; Kuhnz, L.A.; Smith, K.L.

    2016-01-01

    The deep ocean benthic environment plays a role in long-term carbon sequestration. Understanding carbon cycling in the deep ocean floor is critical to evaluate the impact of changing climate on the oceanic systems. Linear inverse modeling was used to quantify carbon transfer between compartments in

  7. Carbon cycling in the deep eastern North Pacific benthic food web: Investigating the effect of organic carbon input

    NARCIS (Netherlands)

    Dunlop, K.M.; Van Oevelen, D.; Ruhl, H.A.; Huffard, C.L.; Kuhnz, L.A.; Smith, K.L.

    2016-01-01

    The deep ocean benthic environment plays a role in long-term carbon sequestration. Understanding carbon cycling in the deep ocean floor is critical to evaluate the impact of changing climate on the oceanic systems. Linear inverse modeling was used to quantify carbon transfer between compartments in

  8. Benthic nutrient fluxes along the Laurentian Channel: Impacts on the N budget of the St. Lawrence marine system

    Science.gov (United States)

    Thibodeau, Benoît; Lehmann, Moritz F.; Kowarzyk, Jacqueline; Mucci, Alfonso; Gélinas, Yves; Gilbert, Denis; Maranger, Roxane; Alkhatib, Mohammad

    2010-12-01

    Water column concentrations and benthic fluxes of dissolved inorganic nitrogen (DIN) and oxygen (DO) were measured in the Gulf of St. Lawrence and the Upper and Lower St. Lawrence Estuary (USLE and LSLE, respectively) to assess the nitrogen (N) budget in the St. Lawrence (SL) system, as well as to elucidate the impact of bottom water hypoxia on fixed-N removal in the LSLE. A severe nitrate deficit, with respect to ambient phosphate concentrations (N*˜-10 μmol L -1), was observed within and in the vicinity of the hypoxic bottom water of the LSLE. Given that DO concentrations in the water column have remained above 50 μmol L -1, nitrate reduction in suboxic sediments, rather than in the water column, is most likely responsible for the removal of fixed N from the SL system. Net nitrate fluxes into the sediments, derived from pore water nitrate concentration gradients, ranged from 190 μmol m -2 d -1 in the hypoxic western LSLE to 100 μmol m -2 d -1 in the Gulf. The average total benthic nitrate reduction rate for the Laurentian Channel (LC) is on the order of 690 μmol m -2 d -1, with coupled nitrification-nitrate reduction accounting for more than 70%. Using average nitrate reduction rates derived from the observed water column nitrate deficit, the annual fixed-N elimination within the three main channels of the Gulf of St. Lawrence and LSLE was estimated at 411 × 10 6 t N, yielding an almost balanced N budget for the SL marine system.

  9. Benthic phosphorus and iron budgets for three NW African slope sediments: a balance approach

    Directory of Open Access Journals (Sweden)

    K. Küster-Heins

    2010-02-01

    Full Text Available Despite intensive research on the different domains of the marine phosphorus (P cycle during the last decades, frequently discussed open questions still exist especially on controlling factors for the benthic behaviour of P and its general distribution in sediment-pore water systems. Steady state or the internal balance of all relevant physical and (biogeochemical processes are amongst the key issues. In this study we present and discuss an extended data set from surface sediments recovered from three locations on the NW African continental slope. Pore water data and results from sequential sediment extractions give clear evidence to the well-known close relationship between the benthic cycles of P and iron. Accordingly, most of the dissolved phosphate must have been released by microbially catalyzed reductive dissolution of iron (oxhydroxides. However, rates of release and association of P and iron, respectively, are not directly represented in profiles of element specific sediment compositions. Results from steady-state based transport-reaction modelling suggest that particle mixing due to active bioturbation, or rather a physical net downward transport of P associated to iron (oxyhydroxides, is an essential process for the balance of the inspected benthic cycles. This study emphasizes the importance of balancing analytical data for a comprehensive understanding of all processes involved in biogeochemical cycles.

  10. Perturbations in the carbon budget of the tropics.

    Science.gov (United States)

    Grace, John; Mitchard, Edward; Gloor, Emanuel

    2014-10-01

    The carbon budget of the tropics has been perturbed as a result of human influences. Here, we attempt to construct a 'bottom-up' analysis of the biological components of the budget as they are affected by human activities. There are major uncertainties in the extent and carbon content of different vegetation types, the rates of land-use change and forest degradation, but recent developments in satellite remote sensing have gone far towards reducing these uncertainties. Stocks of carbon as biomass in tropical forests and woodlands add up to 271 ± 16 Pg with an even greater quantity of carbon as soil organic matter. Carbon loss from deforestation, degradation, harvesting and peat fires is estimated as 2.01 ± 1.1 Pg annum(-1); while carbon gain from forest and woodland growth is 1.85 ± 0.09 Pg annum(-1). We conclude that tropical lands are on average a small carbon source to the atmosphere, a result that is consistent with the 'top-down' result from measurements in the atmosphere. If they were to be conserved, they would be a substantial carbon sink. Release of carbon as carbon dioxide from fossil fuel burning in the tropics is 0.74 Pg annum(-1) or 0.57 MgC person(-1) annum(-1) , much lower than the corresponding figures from developed regions of the world.

  11. The Oxidant Budget of Dissolved Organic Carbon Driven Isotope Excursions

    Science.gov (United States)

    Bristow, T. F.; Kennedy, M. J.

    2008-12-01

    Negative carbon isotope values, falling below the mantle average of about -5 per mil, in carbonate phases of Ediacaran age sedimentary rocks are widely regarded as reflecting negative excursions in the carbon isotopic composition of seawater lasting millions of years. These isotopic signals form the basis of chemostratigraphic correlations between Ediacaran aged sections in different parts of the world, and have been used to track the oxidation of the biosphere. However, these isotopic values are difficult to accommodate within limits prescribed by the current understanding of the carbon cycle, and a hypothetical Precambrian ocean dissolved organic carbon (DOC) pool 100 to 1000 times the size of the modern provides a potential source of depleted carbon not considered in Phanerozoic carbon cycle budgets. We present box model results that show the remineralization of such a DOC pool to drive an isotope excursion of the magnitude observed in the geological record exhausts global budgets of free oxygen and sulfate in 800 k.y. These results are incompatible with the estimated duration of late Ediacaran isotope excursions of more than 10 m.y., as well as geochemical and biological indicators that oceanic sulfate and oxygen levels were maintained or even increased at the same time. Therefore the carbon isotope record is probably not a useful tool for monitoring oxygen levels in the atmosphere and ocean. Covariation between the carbon and oxygen isotope records is often observed during negative excursions and is indicative of local processes or diagenetic overprinting.

  12. Examining the Evidence for the Influence of Carbonate Saturation State on Benthic Foraminiferal Mg/Ca

    Science.gov (United States)

    Martin, P. A.; Lea, D. W.; McCorkle, D. C.

    2002-12-01

    Benthic foraminiferal Mg/Ca paleothermometry is based on an empirical relationship between the Mg/Ca of benthic foraminifera recovered from core tops and in situ bottom water temperatures (Rosenthal, 1997; Martin et al, in press; Lear et al, in review). While there is a tight correlation between shell Mg/Ca and temperature over a broad range of temperatures (-1 to 20 degrees C), Mg/Ca variation over the small range of deep water temperatures reveals departures from the calibration curve at low temperatures. Lower Mg/Ca values are generally associated with the deepest sites from the Atlantic and Pacific, contributing to an apparently steeper Mg/Ca-T response for abyssal benthics. The steeper response of abyssal benthics may reflect an influence of decreasing carbonate saturation with depth. Saturation related effects have already been documented for Mg in planktonic foraminifera and for other metals (Cd, Ba, and Zn) in benthic foraminifera shells (see Marchitto and ref. therein). Although it is difficult to definitively separate the effects of various environmental parameters (including temperature, depth, and relative saturation states), which often change in unison, we can use the core top Mg/Ca data to estimate the potential influence of saturation state. An alternative calibration of the benthic Mg/Ca - T relationship can be derived from core top benthic foraminifera based only on sites bathed in waters above carbonate saturation that yields a slightly smaller change in Mg/Ca per degree C (~9.5% vs. 11%) but better explains benthic Mg/Ca from the coldest sites (-1degrees C). Using this alternative Mg/Ca -T relation and a subset of data from the Ceara Rise and Ontong Java Plateau, we can estimate a maximum Mg/Ca offset attributable to saturation state. By comparing core top and downcore data, we can also address possible differences in the primary Mg-T response and carbonate saturation related effects between different genera (Cibicidoides and Uvigerina).

  13. Closing the North American Carbon Budget: Continental Margin Fluxes Matter!

    Science.gov (United States)

    Najjar, R.; Benway, H. M.; Siedlecki, S. A.; Boyer, E. W.; Cai, W. J.; Coble, P. G.; Cross, J. N.; Friedrichs, M. A.; Goni, M. A.; Griffith, P. C.; Herrmann, M.; Lohrenz, S. E.; Mathis, J. T.; McKinley, G. A.; Pilskaln, C. H.; Smith, R. A.; Alin, S. R.

    2015-12-01

    Despite their relatively small surface area, continental margins are regions of intense carbon and nutrient processing, export and exchange, and thus have a significant impact on global biogeochemical cycles. In response to recommendations for regional synthesis and carbon budget estimation for North America put forth in the North American Continental Margins workshop report (Hales et al., 2008), the Ocean Carbon and Biogeochemistry (OCB) Program and North American Carbon Program (NACP) began coordinating a series of collaborative, interdisciplinary Coastal CARbon Synthesis (CCARS) research activities in five coastal regions of North America (Atlantic Coast, Pacific Coast, Gulf of Mexico, Arctic, Laurentian Great Lakes) to improve quantitative assessments of the North American carbon budget. CCARS workshops and collaborative research activities have resulted in the development of regional coastal carbon budgets based on recent literature- and model-based estimates of major carbon fluxes with estimated uncertainties. Numerous peer-reviewed papers and presentations by involved researchers have highlighted these findings and provided more in-depth analyses of processes underlying key carbon fluxes in continental margin systems. As a culminating outcome of these synthesis efforts, a comprehensive science plan highlights key knowledge gaps identified during this synthesis and provides explicit guidance on future research and observing priorities in continental margin systems to help inform future agency investments in continental margins research. This presentation will provide an overview of regional and flux-based (terrestrial inputs, biological transformations, sedimentary processes, atmospheric exchanges, lateral carbon transport) synthesis findings and key recommendations in the science plan, as well as a set of overarching priorities and recommendations on observations and modeling approaches for continental margin systems.

  14. Trends in Benthic macroinvertebrate community Biomass and Energy Budgets in Lake Sevan, 1928-2004

    Science.gov (United States)

    Stapanian, Martin A.; Jenderedjian, K.; Hakobyan, S.

    2012-01-01

    Water levels of Lake Sevan (Armenia) were artificially lowered by nearly 20 m between 1949 and 1997. Lowered water levels, combined with increased eutrophication, were associated with seasonally anoxic conditions (lasting 1–4 months) near the bottom of the profundal zone each year during 1976–2004. In addition, the extents of the macrophyte zone and of certain substrate types were severely reduced following drawdown. Maximal depth of occurrence decreased by 2–44 m for at least for 50 species of benthic macroinvertebrates between 1982 and 2004 compared to 1937–1961. Species richness of benthic macroinvertebrates declined from 25 to three species at depths where seasonal anoxia occurred. Total biomass increased by a factor of 10 from the period 1928–1948 to 1976–1979 then declined by a factor of 3 to 4 between 1987 and 2004. Energy flow through detritivores was more than tripled during 1976–2004 compared to 1928–1971, a result of increased plankton primary production. In contrast, energy flow through herbivorous benthic macroinvertebrates decreased by a factor of nearly 5, due to reduced areal coverage of macrophytes. Energy flow through filter feeders did not change over the time period examined, but energy flow through the entire zoobenthos community was nearly tripled. The biomasses of Oligochaeta, Chironomidae, and total zoobenthos showed a delayed response to changes in primary production of 7–9, 2, and 2–4 years, respectively. These patterns may provide a basis to predict results of restoration efforts based on the abundance of the zoobenthos in future years as the level of the lake is restored and water quality improves.

  15. The carbon budget of South Asia

    Digital Repository Service at National Institute of Oceanography (India)

    Patra, P.K.; Canadell, J.G.; Houghton, R.A.; Piao, S.L.; Oh, N.-H.; Ciais, P.; Manjunath, K.R.; Chhabra, A.; Wang, T.; Bhattacharya, T.; Bousquet, P.; Hartman, J.; Ito, A.; Mayorga, E.; Niwa, Y.; Raymond, P.; Sarma, V.V.S.S.; Lasco, R.

    the combustion of fossil fuels of 444 Tg C yr sup(-1) for the 2000s, we estimate a net CO sub(2) land–atmosphere flux of 297 Tg C yr sup(-1). In addition to CO sub(2), a fraction of the sequestered carbon in terrestrial ecosystems is released to the atmosphere...

  16. FOOD SOURCES AND CARBON BUDGET OF CHINESE PRAWN PENAEUS CHINENSIS

    Institute of Scientific and Technical Information of China (English)

    董双林; 张硕; 王芳

    2002-01-01

    This study deals with contribution of artificial food pellet and natural food to Chinese prawn (Penaeus orientalis) growth in a semiintensive culture pond. The prawn carbon consumption, budget, and the effects of some factors on the budget were investigated. The results showed that 26.2% of P. orientalis growth carbon came from formulated feed at the initial culture stage (when the prawns were 0.06±0.01 g in wet weight), and was 62.5% when the prawns were 9.56±1.04 g. The remaining part of the growth carbon was derived from organic fertilizer and natural food. The highest growth rate occurred at 20×10-3 salinity. Suitable salinity for culturing Chinese prawn was (20-28)×10-3.

  17. Effects of coral reef benthic primary producers on dissolved organic carbon and microbial activity.

    Directory of Open Access Journals (Sweden)

    Andreas F Haas

    Full Text Available Benthic primary producers in marine ecosystems may significantly alter biogeochemical cycling and microbial processes in their surrounding environment. To examine these interactions, we studied dissolved organic matter release by dominant benthic taxa and subsequent microbial remineralization in the lagoonal reefs of Moorea, French Polynesia. Rates of photosynthesis, respiration, and dissolved organic carbon (DOC release were assessed for several common benthic reef organisms from the backreef habitat. We assessed microbial community response to dissolved exudates of each benthic producer by measuring bacterioplankton growth, respiration, and DOC drawdown in two-day dark dilution culture incubations. Experiments were conducted for six benthic producers: three species of macroalgae (each representing a different algal phylum: Turbinaria ornata--Ochrophyta; Amansia rhodantha--Rhodophyta; Halimeda opuntia--Chlorophyta, a mixed assemblage of turf algae, a species of crustose coralline algae (Hydrolithon reinboldii and a dominant hermatypic coral (Porites lobata. Our results show that all five types of algae, but not the coral, exuded significant amounts of labile DOC into their surrounding environment. In general, primary producers with the highest rates of photosynthesis released the most DOC and yielded the greatest bacterioplankton growth; turf algae produced nearly twice as much DOC per unit surface area than the other benthic producers (14.0±2.8 µmol h⁻¹ dm⁻², stimulating rapid bacterioplankton growth (0.044±0.002 log10 cells h⁻¹ and concomitant oxygen drawdown (0.16±0.05 µmol L⁻¹ h⁻¹ dm⁻². Our results demonstrate that benthic reef algae can release a significant fraction of their photosynthetically-fixed carbon as DOC, these release rates vary by species, and this DOC is available to and consumed by reef associated microbes. These data provide compelling evidence that benthic primary producers differentially influence

  18. Effects of coral reef benthic primary producers on dissolved organic carbon and microbial activity.

    Science.gov (United States)

    Haas, Andreas F; Nelson, Craig E; Wegley Kelly, Linda; Carlson, Craig A; Rohwer, Forest; Leichter, James J; Wyatt, Alex; Smith, Jennifer E

    2011-01-01

    Benthic primary producers in marine ecosystems may significantly alter biogeochemical cycling and microbial processes in their surrounding environment. To examine these interactions, we studied dissolved organic matter release by dominant benthic taxa and subsequent microbial remineralization in the lagoonal reefs of Moorea, French Polynesia. Rates of photosynthesis, respiration, and dissolved organic carbon (DOC) release were assessed for several common benthic reef organisms from the backreef habitat. We assessed microbial community response to dissolved exudates of each benthic producer by measuring bacterioplankton growth, respiration, and DOC drawdown in two-day dark dilution culture incubations. Experiments were conducted for six benthic producers: three species of macroalgae (each representing a different algal phylum: Turbinaria ornata--Ochrophyta; Amansia rhodantha--Rhodophyta; Halimeda opuntia--Chlorophyta), a mixed assemblage of turf algae, a species of crustose coralline algae (Hydrolithon reinboldii) and a dominant hermatypic coral (Porites lobata). Our results show that all five types of algae, but not the coral, exuded significant amounts of labile DOC into their surrounding environment. In general, primary producers with the highest rates of photosynthesis released the most DOC and yielded the greatest bacterioplankton growth; turf algae produced nearly twice as much DOC per unit surface area than the other benthic producers (14.0±2.8 µmol h⁻¹ dm⁻²), stimulating rapid bacterioplankton growth (0.044±0.002 log10 cells h⁻¹) and concomitant oxygen drawdown (0.16±0.05 µmol L⁻¹ h⁻¹ dm⁻²). Our results demonstrate that benthic reef algae can release a significant fraction of their photosynthetically-fixed carbon as DOC, these release rates vary by species, and this DOC is available to and consumed by reef associated microbes. These data provide compelling evidence that benthic primary producers differentially influence reef microbial

  19. Volatile organic compound emissions in relation to plant carbon fixation and the terrestrial carbon budget

    NARCIS (Netherlands)

    Kesselmeier, J.; Ciccioli, P.; Kuhn, U.; Stefani, P.; Biesenthal, T.; Rottenberger, S.; Wolf, A.; Vitullo, M.; Valentini, R.; Nobre, A.; Kabat, P.; Andreae, M.O.

    2002-01-01

    A substantial amount of carbon is emitted by terrestrial vegetation as biogenic volatile organic compounds (VOC), which contributes to the oxidative capacity of the atmosphere, to particle production and to the carbon cycle. With regard to the carbon budget of the terrestrial biosphere, a release of

  20. Widespread kelp-derived carbon in pelagic and benthic nearshore fishes suggested by stable isotope analysis

    Science.gov (United States)

    von Biela, Vanessa R.; Newsome, Seth D.; Bodkin, James L.; Kruse, Gordon H.; Zimmerman, Christian E.

    2016-11-01

    Kelp forests provide habitat for diverse and abundant fish assemblages, but the extent to which kelp provides a source of energy to fish and other predators is unclear. To examine the use of kelp-derived energy by fishes we estimated the contribution of kelp- and phytoplankton-derived carbon using carbon (δ13C) and nitrogen (δ15N) isotopes measured in muscle tissue. Benthic-foraging kelp greenling (Hexagrammos decagrammus) and pelagic-foraging black rockfish (Sebastes melanops) were collected at eight sites spanning ∼35 to 60°N from the California Current (upwelling) to Alaska Coastal Current (downwelling) in the northeast Pacific Ocean. Muscle δ13C values were expected to be higher for fish tissue primarily derived from kelp, a benthic macroalgae, and lower for tissue primarily derived from phytoplankton, pelagic microalgae. Muscle δ13C values were higher in benthic-feeding kelp greenling than in pelagic-feeding black rockfish at seven of eight sites, indicating more kelp-derived carbon in greenling as expected. Estimates of kelp carbon contributions ranged from 36 to 89% in kelp greenling and 32 to 65% in black rockfish using carbon isotope mixing models. Isotopic evidence suggests that these two nearshore fishes routinely derive energy from kelp and phytoplankton, across coastal upwelling and downwelling systems. Thus, the foraging mode of nearshore predators has a small influence on their ultimate energy source as energy produced by benthic macroalgae and pelagic microalgae were incorporated in fish tissue regardless of feeding mode and suggest strong and widespread benthic-pelagic coupling. Widespread kelp contributions to benthic- and pelagic-feeding fishes suggests that kelp energy provides a benefit to nearshore fishes and highlights the potential for kelp and fish production to be linked.

  1. The carbon budget of South Asia

    Directory of Open Access Journals (Sweden)

    P. K. Patra

    2012-10-01

    Full Text Available The source and sinks of carbon dioxide (CO2 and methane (CH4 due to anthropogenic and natural biospheric activities were estimated for the South Asia region (Bangladesh, Bhutan, India, Nepal, Pakistan and Sri Lanka. Flux estimates were based on top-down methods that use inversions of atmospheric data, and bottom-up methods that use field observations, satellite data, and terrestrial ecosystem models. Based on atmospheric CO2 inversions, the net biospheric CO2 flux in South Asia (equivalent to the Net Biome Productivity, NBP was a sink, estimated at −104 ± 150 Tg C yr−1 during 2007–2008. Based on the bottom-up approach, the net biospheric CO2 flux is estimated to be −191 ± 193 Tg C yr−1 during the period of 2000–2009. This last net flux results from the following flux components: (1 the Net Ecosystem Productivity, NEP (net primary production minus heterotrophic respiration of −220 ± 186 Tg C yr−1 (2 the annual net carbon flux from land-use change of −14 ± 50 Tg C yr−1, which resulted from a sink of −16 Tg C yr−1 due to the establishment of tree plantations and wood harvest, and a source of 2 Tg C yr−1 due to the expansion of croplands; (3 the riverine export flux from terrestrial ecosystems to the coastal oceans of +42.9 Tg C yr−1; and (4 the net CO2 emission due to biomass burning of +44.1 ± 13.7 Tg C yr−1. Including the emissions from the combustion of fossil fuels of 444 Tg C yr−1 for the decades of 2000s, we estimate a net CO2 land-to-atmosphere flux of 297 Tg C yr−1. In addition to CO2, a fraction of the sequestered carbon in terrestrial ecosystems is released to the atmosphere as CH4. Based on bottom-up and top-down estimates, and chemistry-transport modeling, we estimate that 37 ± 3.7 Tg C

  2. The carbon budget of South Asia

    Directory of Open Access Journals (Sweden)

    P. K. Patra

    2013-01-01

    Full Text Available The source and sinks of carbon dioxide (CO2 and methane (CH4 due to anthropogenic and natural biospheric activities were estimated for the South Asian region (Bangladesh, Bhutan, India, Nepal, Pakistan and Sri Lanka. Flux estimates were based on top-down methods that use inversions of atmospheric data, and bottom-up methods that use field observations, satellite data, and terrestrial ecosystem models. Based on atmospheric CO2 inversions, the net biospheric CO2 flux in South Asia (equivalent to the Net Biome Productivity, NBP was a sink, estimated at −104 ± 150 Tg C yr−1 during 2007–2008. Based on the bottom-up approach, the net biospheric CO2 flux is estimated to be −191 ± 193 Tg C yr−1 during the period of 2000–2009. This last net flux results from the following flux components: (1 the Net Ecosystem Productivity, NEP (net primary production minus heterotrophic respiration of −220 ± 186 Tg C yr−1 (2 the annual net carbon flux from land-use change of −14 ± 50 Tg C yr−1, which resulted from a sink of −16 Tg C yr−1 due to the establishment of tree plantations and wood harvest, and a source of 2 Tg C yr−1 due to the expansion of croplands; (3 the riverine export flux from terrestrial ecosystems to the coastal oceans of +42.9 Tg C yr−1; and (4 the net CO2 emission due to biomass burning of +44.1 ± 13.7 Tg C yr−1. Including the emissions from the combustion of fossil fuels of 444 Tg C yr−1 for the 2000s, we estimate a net CO2 land–atmosphere flux of 297 Tg C yr−1. In addition to CO2, a fraction of the sequestered carbon in terrestrial ecosystems is released to the atmosphere as CH4. Based on bottom-up and top-down estimates, and chemistry-transport modeling, we estimate that 37 ± 3.7 Tg C yr−1

  3. Assessment of the direct effects of biogenic and petrogenic activated carbon on benthic organisms.

    Science.gov (United States)

    Lillicrap, Adam; Schaanning, Morten; Macken, Ailbhe

    2015-03-17

    Activated carbon (AC) has long been associated with the capacity to effectively remove organic substances from aquatic and sediment matrices; however, its use in remediation purposes has drawn some concern due to possible impacts on benthic communities. Within the inner Oslofjord, the use of AC has been well documented for reducing the risks associated with dioxins or dioxin-like compounds from contaminated areas. However, benthic surveys performed on areas treated with AC have revealed that the abundance of organisms inhabiting these areas can be reduced significantly in the subsequent years following treatment. The reason for the reduction in the benthic communities is currently unknown, and therefore, an integrated approach to assess the effects of 2 different forms of AC (biogenic and petrogenic) on benthic organisms has been performed. A battery of 3 different benthic organisms with different feeding and life-cycle processes has been used encompassing sediment surface feeders, sediment ingestors, and sediment reworkers. Results of the tests indicated that although AC is not acutely toxic at concentrations up to 1000 mg/L, there may be physical effects of the substance on benthic dwelling organisms at environmentally relevant concentrations of AC at remediated sites.

  4. Benthic Carbon mineralization and nutrient turnover in a Scottish Sea Loch

    DEFF Research Database (Denmark)

    Glud, Ronnie N.; Berg, Peter; Stahl, Henrik

    2016-01-01

    Based on in situ microprofiles, chamber incubations and eddy covariance measurements, we investigated the benthic carbon mineralization and nutrient regeneration in a ~65-m-deep sedimentation basin of Loch Etive, UK. The sediment hosted a considerable amount of infauna that was dominated by the b...

  5. The North American Carbon Budget Past, Present and Future

    Science.gov (United States)

    Hayes, D. J.; Vargas, R.; Alin, S. R.; Conant, R. T.; Hutyra, L.; Jacobson, A. R.; Kurz, W. A.; Liu, S.; McGuire, A. D.; Poulter, B.; Woodall, C. W.

    2016-12-01

    Scientific information quantifying and characterizing the continental-scale carbon budget is necessary for developing national and international policy on climate change. The North American continent (NA) has been considered to be a significant net source of carbon to the atmosphere, with fossil fuel emissions from the U.S., Canada and Mexico far outpacing uptake on land, inland waters and adjacent coastal oceans. As reported in the First State of the Carbon Cycle Report (SOCCR-1), the three countries combined to emit approximately 1.8 billion tons of carbon in 2003, or 27% of the global total fossil fuel inventory. Based on inventory data from various sectors, SOCCR-1 estimated a 500 MtC/yr natural sink that offset about 30% of emissions primarily through forest growth, storage in wood products and sequestration in agricultural soils. Here we present a synthesis of the NA carbon budget for the next report (SOCCR-2) based on updated inventory data and new research over the last decade. After increasing at a rate of 1% per year over the previous 30 years, the combined fossil fuel emissions from the three countries show a decreasing trend over the last decade. The decline is due to the economic recession along with increasing carbon efficiency, and the result is a lower share (20%) of the global total. Synthesizing inventory-based data from forest, agriculture and other sectors over the past decade results in a smaller estimate for terrestrial C uptake (350 MtC/yr, or about 20% of emissions) than SOCCR-1, but excludes potential sinks of highly uncertain magnitude. Estimates from atmospheric and biosphere models suggest stronger sinks on the order of 30 to 50% of emissions, but these vary widely within and across the ensembles. This updated report draws attention to key data gaps in carbon accounting frameworks and uncertainties in modeling approaches, but also highlights integrated approaches for improving our understanding of the NA carbon cycle.

  6. Annual benthic metabolism and organic carbon fluxes in a semi-enclosed Mediterranean bay dominated by the macroalgae Caulerpa prolifera.

    Directory of Open Access Journals (Sweden)

    Sergio eRuiz-Halpern

    2014-12-01

    Full Text Available Coastal areas play an important role on carbon cycling. Elucidating the dynamics on the production, transport and fate of organic carbon is relevant to gain a better understanding of the role coastal areas play in the global carbon budget. Here, we assess the metabolic status and associated organic carbon fluxes of a semi-enclosed Mediterranean bay supporting a meadow of Caulerpa prolifera. We test whether the EDOC pool is a significant component of the organic carbon pool and associated fluxes in this ecosystem. The Bay of Portocolom was in net metabolic balance on a yearly basis, but heterotrophic during the summer months. Community respiration (CR was positively correlated to C. prolifera biomass, while net community production (NCP had a negative correlation. The benthic compartment represented, on average, 72.6 ± 5.2 % of CR and 86.8 ± 4.5 % of gross primary production (GPP. Dissolved organic carbon (DOC production peaked in summer and was always positive, with the incubations performed in the dark almost doubling the flux of those performed in the light. Exchangeable dissolved organic carbon (EDOC, however, oscillated between production and uptake, being completely recycled within the system and representing around 14% of the DOC flux. The pools of bottom and surface DOC were high for an oligotrophic environment, and were positively correlated to the pool of EDOC. Thus, despite being in metabolic balance, this ecosystem acted as a conduit for organic carbon (OC, as it is able to export OC to adjacent areas derived from allochtonous inputs during heterotrophic conditions. These inputs likely come from groundwater discharge, human activity in the watershed, delivered to the sediments through the high capacity of C. prolifera to remove particles from the water column, and from the air-water exchange of EDOC, demonstrating that these communities are a major contributor to the cycling of OC in coastal embayments.

  7. The terrestrial carbon budget of South and Southeast Asia

    Science.gov (United States)

    Cervarich, Matthew; Shu, Shijie; Jain, Atul K.; Arneth, Almut; Canadell, Josep; Friedlingstein, Pierre; Houghton, Richard A.; Kato, Etsushi; Koven, Charles; Patra, Prabir; Poulter, Ben; Sitch, Stephen; Stocker, Beni; Viovy, Nicolas; Wiltshire, Andy; Zeng, Ning

    2016-10-01

    Accomplishing the objective of the current climate policies will require establishing carbon budget and flux estimates in each region and county of the globe by comparing and reconciling multiple estimates including the observations and the results of top-down atmospheric carbon dioxide (CO2) inversions and bottom-up dynamic global vegetation models. With this in view, this study synthesizes the carbon source/sink due to net ecosystem productivity (NEP), land cover land use change (E LUC), fires and fossil burning (E FIRE) for the South Asia (SA), Southeast Asia (SEA) and South and Southeast Asia (SSEA = SA + SEA) and each country in these regions using the multiple top-down and bottom-up modeling results. The terrestrial net biome productivity (NBP = NEP - E LUC - E FIRE) calculated based on bottom-up models in combination with E FIRE based on GFED4s data show net carbon sinks of 217 ± 147, 10 ± 55, and 227 ± 279 TgC yr-1 for SA, SEA, and SSEA. The top-down models estimated NBP net carbon sinks were 20 ± 170, 4 ± 90 and 24 ± 180 TgC yr-1. In comparison, regional emissions from the combustion of fossil fuels were 495, 275, and 770 TgC yr-1, which are many times higher than the NBP sink estimates, suggesting that the contribution of the fossil fuel emissions to the carbon budget of SSEA results in a significant net carbon source during the 2000s. When considering both NBP and fossil fuel emissions for the individual countries within the regions, Bhutan and Laos were net carbon sinks and rest of the countries were net carbon source during the 2000s. The relative contributions of each of the fluxes (NBP, NEP, E LUC, and E FIRE, fossil fuel emissions) to a nation’s net carbon flux varied greatly from country to country, suggesting a heterogeneous dominant carbon fluxes on the country-level throughout SSEA.

  8. Carbon budgets and carbon sequestration potential of Indian forests

    NARCIS (Netherlands)

    Kaul, M.

    2010-01-01

    Keywords: Carbon uptake, Forest biomass, Bioenergy, Land use change, Indian forests, Deforestation, Afforestation, Rotation length, Trees outside forests. Global climate change is a widespread and growing concern that has led to extensive international discussions and negotiations. Responses to

  9. Carbon budgets and carbon sequestration potential of Indian forests

    NARCIS (Netherlands)

    Kaul, M.

    2010-01-01

    Keywords: Carbon uptake, Forest biomass, Bioenergy, Land use change, Indian forests, Deforestation, Afforestation, Rotation length, Trees outside forests. Global climate change is a widespread and growing concern that has led to extensive international discussions and negotiations. Responses to thi

  10. Carbon budgets and carbon sequestration potential of Indian forests

    NARCIS (Netherlands)

    Kaul, M.

    2010-01-01

    Keywords: Carbon uptake, Forest biomass, Bioenergy, Land use change, Indian forests, Deforestation, Afforestation, Rotation length, Trees outside forests. Global climate change is a widespread and growing concern that has led to extensive international discussions and negotiations. Responses to thi

  11. Carbon and nitrogen budgets of the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Somasundar, K.; Rajendran, A.; DileepKumar, M.; SenGupta, R.

    -deficient layers through microbial activity. Moreover, the large flux of organic matter as a result of surface productivity and terrestrial input into the sea will have an impact on carbon and nitrogen budgets. Re- ducing environments in the sea are conducive...- tween 2450 and 5790 mg C m -z day -~. in high-productive zones. It is thus estimated from the mean productivity rate that, on average, ~ 2.45 X 10 t 5 g C is fixed annually through primary productivity in the Arabian Sea. Most of the organic material...

  12. Molar tooth carbonates and benthic methane fluxes in Proterozoic oceans

    Science.gov (United States)

    Shen, Bing; Dong, Lin; Xiao, Shuhai; Lang, Xianguo; Huang, Kangjun; Peng, Yongbo; Zhou, Chuanming; Ke, Shan; Liu, Pengju

    2016-01-01

    Molar tooth structures are ptygmatically folded and microspar-filled structures common in early- and mid-Proterozoic (~2,500-750 million years ago, Ma) subtidal successions, but extremely rare in rocks isotopes, we show that molar tooth structures may have formed within sediments where microbial sulphate reduction and methanogenesis converged. The convergence was driven by the abundant production of methyl sulphides (dimethyl sulphide and methanethiol) in euxinic or H2S-rich seawaters that were widespread in Proterozoic continental margins. In this convergence zone, methyl sulphides served as a non-competitive substrate supporting methane generation and methanethiol inhibited anaerobic oxidation of methane, resulting in the buildup of CH4, formation of degassing cracks in sediments and an increase in the benthic methane flux from sediments. Precipitation of crack-filling microspar was driven by methanogenesis-related alkalinity accumulation. Deep ocean ventilation and oxygenation around 750 Ma brought molar tooth structures to an end.

  13. Comprehensive multiyear carbon budget of a temperate headwater stream

    Science.gov (United States)

    Argerich, Alba; Haggerty, Roy; Johnson, Sherri L.; Wondzell, Steven M.; Dosch, Nicholas; Corson-Rikert, Hayley; Ashkenas, Linda R.; Pennington, Robert; Thomas, Christoph K.

    2016-05-01

    Headwater streams comprise nearly 90% of the total length of perennial channels in global catchments. They mineralize organic carbon entering from terrestrial systems, evade terrestrial carbon dioxide (CO2), and generate and remove carbon through in-stream primary production and respiration. Despite their importance, headwater streams are often neglected in global carbon budgets primarily because of a lack of available data. We measured these processes, in detail, over a 10 year period in a stream draining a 96 ha forested watershed in western Oregon, USA. This stream, which represents only 0.4% of the watershed area, exported 159 kg C ha-1 yr-1, similar to the global exports for large rivers. Stream export was dominated by downstream transport of dissolved inorganic carbon (63 kg C ha-1 yr-1) and by evasion of CO2 to the atmosphere (42 kg C ha-1 yr-1), leaving the remainder of 51 kg C ha-1 yr-1 for downstream transport of organic carbon (17 kg C ha-1 yr-1 and 34 kg C ha-1 yr-1 in dissolved and particulate form, respectively).

  14. Quantifying the Potential Influence of Carbonate Saturation State on Benthic Foraminiferal Mg/Ca

    Science.gov (United States)

    Martin, P. A.; Lea, D. W.; McCorkle, D. C.

    2002-05-01

    Benthic foraminiferal Mg/Ca paleothermometry is based on an empirical relationship between the Mg/Ca of benthic foraminifera recovered from core tops and in situ bottom water temperatures (Rosenthal, 1997; Martin et al, in press; Lear et al, in review). While there is a tight correlation between shell Mg/Ca and temperature over a broad range of temperatures (-1 to 20 degrees C), Mg/Ca variation over the small range of deep water temperatures reveals departures from the calibration curve at low temperatures. Lower Mg/Ca values are generally associated with the deepest sites from the Atlantic and Pacific, contributing to an apparently steeper Mg/Ca-T response for abyssal benthics. The steeper response of abyssal benthics may reflect an influence of decreasing carbonate saturation with depth. Dissolution or other saturation related effects have already been documented for Mg in planktonic foraminifera and for other metals (Cd, Ba, and Zn) in benthic foraminifera shells (see Marchitto and ref. therein). Although it is difficult to definitively separate the effects of various environmental parameters (including temperature, depth, and relative saturation states), which often change in unison, we can use to the core top Mg/Ca data to estimate the potential influence of saturation state. An alternative calibration of the benthic Mg/Ca - T relationship can be derived based on core top benthic foraminifera only from sites bathed in waters above carbonate saturation, which yields a slightly smaller change in Mg/Ca per degree C (~9.5% vs. 11%) but better explains benthic Mg/Ca from the coldest sites (-1oC). Using this alternative Mg/Ca -T relation and a subset of the data from the Ceara Rise and Ontong Java Plateau, we can estimate a maximum Mg/Ca offset attributable to saturation state. The uncertainty this implies for downcore reconstructions varies widely (exceeding 1.5oC), depending on the hydrographic setting and which proxy is used to estimate saturation state.

  15. Iceberg killing fields limit huge potential for benthic blue carbon in Antarctic shallows.

    Science.gov (United States)

    Barnes, David K A

    2016-10-26

    Climate-forced ice losses are increasing potential for iceberg-seabed collisions, termed ice scour. At Ryder Bay, West Antarctic Peninsula (WAP) sea ice, oceanography, phytoplankton and encrusting zoobenthos have been monitored since 1998. In 2003, grids of seabed markers, covering 225 m(2) , were established, surveyed and replaced annually to measure ice scour frequency. Disturbance history has been recorded for each m(2) of seabed monitored at 5-25 m for ~13 years. Encrusting fauna, collected from impacted and nonimpacted metres each year, show coincident benthos responses in growth, mortality and mass of benthic immobilized carbon. Encrusting benthic growth was mainly determined by microalgal bloom duration; each day, nanophytoplankton exceeded 200 μg L(-1) produced ~0.05 mm radial growth of bryozoans, and sea temperature >0 °C added 0.002 mm day(-1) . Mortality and persistence of growth, as benthic carbon immobilization, were mainly influenced by ice scour. Nearly 30% of monitored seabed was hit each year, and just 7% of shallows were not hit. Hits in deeper water were more deadly, but less frequent, so mortality decreased with depth. Five-year recovery time doubled benthic carbon stocks. Scour-driven mortality varied annually, with two-thirds of all monitored fauna killed in a single year (2009). Reduced fast ice after 2006 ramped iceberg scouring, killing half the encrusting benthos each year in following years. Ice scour coupled with low phytoplankton biomass drove a phase shift to high mortality and depressed zoobenthic immobilized carbon stocks, which has persevered for 10 years since. Stocks of immobilized benthic carbon averaged nearly 15 g m(-2) . WAP ice scouring may be recycling 80 000 tonnes of carbon yr(-1) . Without scouring, such carbon would remain immobilized and the 2.3% of shelf which are shallows could be as productive as all the remaining continental shelf. The region's future, when glaciers reach grounding lines and iceberg

  16. Benthic foraminiferal assemblages help to understand carbonate mound evolution

    Science.gov (United States)

    Rüggeberg, A.; Dorschel, B.; Dullo, C.; Hebbeln, D.; Freiwald, A.

    2003-04-01

    On- and off-mound sediment cores from Propeller Mound (Porcupine Seabight) were analysed for their benthic foraminiferal assemblages. Benthic foraminifera from the off-mound position show three different assemblages describing the Holocene, Oxygen Isotope Stage (OIS) 2 and late OIS 3. The Holocene assemblage is dominated by Uvigerina mediterranea, Trifarina angulosa, Melonis barleeanum, Hyalinea balthica, Bulimina marginata. These species are related to a higher supply of organic material. The glacial assemblage shows high abundances of Cassidulina teretis, C. reniforme, Globocassidulina subglobosa, and Cibicidoides kullenbergi, implying cold bottom waters and a reduced productivity. The lower part of late OIS 3 is dominated by Elphidium excavatum, which is displaced continuously by very high abundances of C. teretis towards the transition of OIS3/2. E. excavatum, a shallow shelf species generally reported from above 200 m water depth, and high amounts of sediment supplied to the core site points to shelf erosion related to sea level lowering (approx. 50 m). Towards OIS 2 the system returns to normal background sedimentation pattern. We transferred the established off-mound assemblages onto the on-mound core, in which the sediment sequence is incomplete characterised by numerous hiatuses. The Holocene assemblage describes almost the complete core with relative abundances of >20%, interrupted only by three sections with slightly higher amounts of the glacial assemblage, which are not comparable to abundances of >70% of the glacial assemblage found in the off-mound core. These results are in conjunction with stable oxygen isotope data indicating only interstadial values, assuming peak glacial and interglacial sediments to be removed from the mound. Another assemblage described for the on-mound core is dominated by Discanomalina coronata, Gavelinopsis translucens, Planulina ariminensis, Cibicides lobatulus and to a lower degree by Hyrrokkin sarcophaga. These species

  17. Nitrogen budget of the northwestern Black Sea shelf inferred from modeling studies and in situ benthic measurements

    NARCIS (Netherlands)

    Grégoire, M.; Friedrich, J.

    2004-01-01

    A 3D eddy-resolving coupled biogeochemical-hydrodynamical model and in situ observations are used to investigate benthic processes on the Black Sea's NW shelf. Measurements of benthic fluxes (oxygen, nutrients, redox compounds) with in situ flux chambers are analyzed in regard to sediment dynamics

  18. Organic carbon budget for the Gulf of Bothnia

    Science.gov (United States)

    Algesten, Grete; Brydsten, Lars; Jonsson, Per; Kortelainen, Pirkko; Löfgren, Stefan; Rahm, Lars; Räike, Antti; Sobek, Sebastian; Tranvik, Lars; Wikner, Johan; Jansson, Mats

    2006-12-01

    We calculated input of organic carbon to the unproductive, brackish water basin of the Gulf of Bothnia from rivers, point sources and the atmosphere. We also calculated the net exchange of organic carbon between the Gulf of Bothnia and the adjacent marine system, the Baltic Proper. We compared the input with sinks for organic carbon; permanent incorporation in sediments and mineralization and subsequent evasion of CO 2 to the atmosphere. The major fluxes were riverine input (1500 Gg C year - 1 ), exchange with the Baltic Proper (depending on which of several possible DOC concentration differences between the basins that was used in the calculation, the flux varied between an outflow of 466 and an input of 950 Gg C year - 1), sediment burial (1100 Gg C year - 1 ) and evasion to the atmosphere (3610 Gg C year - 1 ). The largest single net flux was the emission of CO 2 to the atmosphere, mainly caused by bacterial mineralization of organic carbon. Input and output did not match in our budget which we ascribe uncertainties in the calculation of the exchange of organic carbon between the Gulf of Bothnia and the Baltic Proper, and the fact that CO 2 emission, which in our calculation represented 1 year (2002) may have been overestimated in comparison with long-term means. We conclude that net heterotrophy of the Gulf of Bothnia was due to input of organic carbon from both the catchment and from the Baltic Proper and that the future degree of net heterotrophy will be sensible to both catchment export of organic carbon and to the ongoing eutrophication of the Baltic Proper.

  19. Carbonate budget of a cold-water coral carbonate mound: Propeller Mound, Porcupine Seabight

    Science.gov (United States)

    Dorschel, Boris; Hebbeln, Dierk; Rüggeberg, Andres; Dullo, Christian

    2007-02-01

    High resolution studies from the Propeller Mound, a cold-water coral carbonate mound in the NE Atlantic, show that this mound consists of >50% carbonate justifying the name ‘carbonate mound’. Through the last ~300,000 years approximately one third of the carbonate has been contributed by cold-water corals, namely Lophelia pertusa and Madrepora oculata. This coral bound contribution to the carbonate budget of Propeller Mound is probably accompanied by an unknown portion of sediments buffered from suspension by the corals. However, extended hiatuses in Propeller Mound sequences only allow the calculation of a net carbonate accumulation. Thus, net carbonate accumulation for the last 175 kyr accounts for only <0.3 g/cm2/kyr, which is even less than for the off-mound sediments. These data imply that Propeller Mound faces burial by hemipelagic sediments as has happened to numerous buried carbonate mounds found slightly to the north of the investigated area.

  20. Differential modification of seawater carbonate chemistry by major coral reef benthic communities

    Science.gov (United States)

    Page, Heather N.; Andersson, Andreas J.; Jokiel, Paul L.; Rodgers, Ku'ulei S.; Lebrato, Mario; Yeakel, Kiley; Davidson, Charlie; D'Angelo, Sydney; Bahr, Keisha D.

    2016-12-01

    Ocean acidification (OA) resulting from uptake of anthropogenic CO2 may negatively affect coral reefs by causing decreased rates of biogenic calcification and increased rates of CaCO3 dissolution and bioerosion. However, in addition to the gradual decrease in seawater pH and Ω a resulting from anthropogenic activities, seawater carbonate chemistry in these coastal ecosystems is also strongly influenced by the benthic metabolism which can either exacerbate or alleviate OA through net community calcification (NCC = calcification - CaCO3 dissolution) and net community organic carbon production (NCP = primary production - respiration). Therefore, to project OA on coral reefs, it is necessary to understand how different benthic communities modify the reef seawater carbonate chemistry. In this study, we used flow-through mesocosms to investigate the modification of seawater carbonate chemistry by benthic metabolism of five distinct reef communities [carbonate sand, crustose coralline algae (CCA), corals, fleshy algae, and a mixed community] under ambient and acidified conditions during summer and winter. The results showed that different communities had distinct influences on carbonate chemistry related to the relative importance of NCC and NCP. Sand, CCA, and corals exerted relatively small influences on seawater pH and Ω a over diel cycles due to closely balanced NCC and NCP rates, whereas fleshy algae and mixed communities strongly elevated daytime pH and Ω a due to high NCP rates. Interestingly, the influence on seawater pH at night was relatively small and quite similar across communities. NCC and NCP rates were not significantly affected by short-term acidification, but larger diel variability in pH was observed due to decreased seawater buffering capacity. Except for corals, increased net dissolution was observed at night for all communities under OA, partially buffering against nighttime acidification. Thus, algal-dominated areas of coral reefs and increased

  1. Benthic Food Webs of the Chukchi and Beaufort Seas: Relative Importance of Ultimate Carbon Sources in a Changing Climate

    Science.gov (United States)

    Dunton, K. H.; Schonberg, S. V.; Mctigue, N.; Bucolo, P. A.; Connelly, T. L.; McClelland, J. W.

    2014-12-01

    Changes in sea-ice cover, coastal erosion, and freshwater run-off have the potential to greatly influence carbon assimilation pathways and affect trophic structure in benthic communities across the western Arctic. In the Chukchi Sea, variations in the duration and timing of ice cover affect the delivery of ice algae to a relatively shallow (40-50 m) shelf benthos. Although ice algae are known as an important spring carbon subsidy for marine benthic fauna, ice algal contributions may also help initiate productivity of an active microphytobenthos. Recent studies provide clear evidence that the microphytobenthos are photosynthetically active, and have sufficient light and nutrients for in situ growth. The assimilation of benthic diatoms from both sources may explain the 13C enrichment observed in benthic primary consumers throughout the northern Chukchi. On the eastern Beaufort Sea coast, shallow (2-4 m) estuarine lagoon systems receive massive subsidies of terrestrial carbon that is assimilated by a benthic fauna of significant importance to upper trophic level species, but again, distinct 13C enrichment in benthic primary consumers suggests the existence of an uncharacterized food source. Since ice algae are absent, we believe the 13C enrichment in benthic fauna is caused by the assimilation of benthic microalgae, as reflected in seasonally high benthic chlorophyll in spring under replete light and nutrient conditions. Our observations suggest that changes in ice cover, on both temporal and spatial scales, are likely to have significant effects on the magnitude and timing of organic matter delivery to both shelf and nearshore systems, and that locally produced organic matter may become an increasingly important carbon subsidy that affects trophic assimilation and secondary ecosystem productivity.

  2. Carbon sink activity and GHG budget of managed European grasslands

    Science.gov (United States)

    Klumpp, Katja; Herfurth, Damien; Soussana, Jean-Francois; Fluxnet Grassland Pi's, European

    2013-04-01

    In agriculture, a large proportion (89%) of greenhouse gas (GHG) emission saving potential may be achieved by means of soil C sequestration. Recent demonstrations of carbon sink activities of European ecosystemes, however, often questioned the existence of C storing grasslands, as though a net sink of C was observed, uncertainty surrounding this estimate was larger than the sink itself (Janssens et al., 2003, Schulze et al., 2009. Then again, some of these estimates were based on a small number of measurements, and on models. Not surprising, there is still, a paucity of studies demonstrating the existence of grassland systems, where C sequestration would exceed (in CO2 equivalents) methane emissions from the enteric fermentation of ruminants and nitrous oxide emissions from managed soils. Grasslands are heavily relied upon for food and forage production. A key component of the carbon sink activity in grasslands is thus the impact of changes in management practices or effects of past and recent management, such as intensification as well as climate (and -variation). We analysed data (i.e. flux, ecological, management and soil organic carbon) from a network of European grassland flux observation sites (36). These sites covered different types and intensities of management, and offered the opportunity to understand grassland carbon cycling and trade-offs between C sinks and CH4 and N2O emissions. For some sites, the assessment of carbon sink activities were compared using two methods; repeated soil inventory and determination of the ecosystem C budget by continuous measurement of CO2 exchange in combination with quantification of other C imports and exports (net C storage, NCS). In general grassland, were a potential sink of C with 60±12 g C /m2.yr (median; min -456; max 645). Grazed sites had a higher NCS compared to cut sites (median 99 vs 67 g C /m2.yr), while permanent grassland sites tended to have a lower NCS compared to temporary sown grasslands (median 64 vs

  3. The Carbon Tetrachloride (CCl4) Budget: Mystery or Not

    Science.gov (United States)

    Liang, Qing; Newman, Paul A.; Daniel, John S.; Reimann, Stefan; Hall, Bradley; Dutton, Geoff; Kuijpers, Lambert J. M.

    2014-01-01

    Carbon tetrachloride (CCl4) is a major anthropogenic ozone-depleting substance and greenhouse gas and has been regulated under the Montreal Protocol. However, atmospheric observations show a very slow decline in CCl4 concentrations, inconsistent with the nearly zero emissions estimate based on the UNEP reported production and feedstock usage in recent years. It is now apparent that there are either unidentified industrial leakages, an unknown production source of CCl4, or large legacy emissions from CCl4 contaminated sites. In this paper we use a global chemistry climate model to assess the budget mystery of atmospheric CCl4. We explore various factors that affect the global trend and the gradient between the Northern and Southern hemispheres or interhemispheric gradient (IHG): emissions, emission hemispheric partitioning, and lifetime variations. We find a present-day emission of 30-50 Gg per yr and a total lifetime 25 - 36 years are necessary to reconcile both the observed CCl4 global trend and IHG.

  4. Economic and policy implications of the cumulative carbon budget

    Science.gov (United States)

    Allen, M. R.; Otto, F. E. L.; Otto, A.; Hepburn, C.

    2014-12-01

    The importance of cumulative carbon emissions in determining long-term risks of climate change presents considerable challenges to policy makers. The traditional notion of "total CO2-equivalent emissions", which forms the backbone of agreements such as the Kyoto Protocol and the European Emissions Trading System, is fundamentally flawed. Measures to reduce short-lived climate pollutants benefit the current generation, while measures to reduce long-lived climate pollutants benefit future generations, so there is no sense in which they can ever be considered equivalent. Debates over the correct metric used to compute CO2-equivalence are thus entirely moot: both long-lived and short-lived emissions will need to be addressed if all generations are to be protected from dangerous climate change. As far as long-lived climate pollutants are concerned, the latest IPCC report highlights the overwhelming importance of carbon capture and storage in determining the cost of meeting the goal of limiting anthropogenic warming to two degrees. We will show that this importance arises directly from the cumulative carbon budget and the role of CCS as the technology of last resort before economic activity needs to be restricted to meet ambitious climate targets. It highlights the need to increase the rate of CCS deployment by orders of magnitude if the option of avoiding two degrees is to be retained. The difficulty of achieving this speed of deployment through conventional incentives and carbon-pricing mechanisms suggests a need for a much more direct mandatory approach. Despite their theoretical economic inefficiency, the success of recent regulatory measures in achieving greenhouse gas emissions reductions in jurisdictions such as the United States suggests an extension of the regulatory approach could be a more effective and politically acceptable means of achieving adequately rapid CCS deployment than conventional carbon taxes or cap-and-trade systems.

  5. Pedogenetic processes and carbon budgets in soils of Queretaro, Mexico

    Science.gov (United States)

    García Calderón, Norma Eugenia; Fuentes Romero, Elizabeth; Hernandez Silva, Gilberto

    2014-05-01

    Pedogenetic processes have been investigated in two different physiographic regions of the state of Querétaro in order to assess the carbon budget of soils, looking into the gains and losses of organic and inorganic carbon: In the mountain region of the natural reserve Sierra Gorda (SG) with soils developed on cretaceous argillites and shales under sub-humid temperate to semi-arid conditions, and in the Transmexican Volcanic Belt (TMVB) with soils developed on acid and intermediate igneous rocks under humid temperate climate in the highlands and semi-arid and subhumid subtropical conditions in the lowlands. The analyses of soil organic carbon (SOC) and soil inorganic carbon (SIC) of the SG region, including additional physical, chemical and mineralogical investigations were based on 103 topsoils in an area of 170 km2. The analyses in the TMVB region were based on the profiles of a soil toposequence from high mountainous positions down to the plains of the lowlands. The results show a SOC accumulation from temperate to semi-arid forest environments, based on processes of humification and clay formation including the influence of exchangeable Ca and the quantity and quality of clay minerals. The turnover rates of SOC and SIC depended largely on the rock parent materials, especially the presence of carbonate rocks. Moreover, we found that the SOC content and distribution was clearly depending on land use, decreasing from forests to agricultural land, such as pasture and cropping areas and were lowest under mining sites. The highest SIC pools were found in accumulation horizons of soils under semi-arid conditions. On all investigated sites SOC decreased the mobility of cations and especially that of heavy metals, such as As, Hg, Sb, Pb, and Cd.

  6. Seasonal carbon cycling in a Greenlandic fjord: an integrated pelagic and benthic study

    DEFF Research Database (Denmark)

    Sørensen, Heidi Louise; Meire, Lorenz; Juul-Pedersen, Thomas

    2015-01-01

    Climate change is expected to have a pronounced effect on biogeochemical cycling in Arctic fjords, but current insight on the biogeochemical functioning of these systems is limited. Here, we present seasonal data on primary production, export of particulate organic carbon (POC), and the coupling...... carbon amounted to 3.2 and 5.3 mol C m−2 yr−1, respectively. Sulfate reduction was the most prominent mineralization pathway, accounting for 69% of the benthic mineralization, while denitrification accounted for 2%. Overall, the carbon mineralization and burial in Kobbefjord were significantly higher...... in ice coverage in higher Arctic Greenlandic fjords will, as a first approximation, entail proportional increases in productivity, mineralization, and burial of organic carbon in the fjords, which will thus become similar to present-day southerly systems....

  7. Carbon budget in East China Sea in spring

    Energy Technology Data Exchange (ETDEWEB)

    Peng Tsunghung; Wanninkhof, R. [National Oceanic and Atmospheric Administration, Miami, FL (United States). Atlantic Oceanographic and Meteorological Labs.; Hung, Jiajang [NSYSU, Kaohsiung (Taiwan, Province of China); Millero, F.J. [Miami Univ., FL (United States). Dept. of Marine and Atmospheric Chemistry]|[Rosenstiel School of Marine and Atmospheric Sciences

    1999-04-01

    Results of total dissolved inorganic carbon (DIC) and total alkalinity (TA) measurements made in the East China Sea (ECS) during a geochemical expedition of KEEP (Kuroshio Edge Exchange Processes) program in May of 1996 show that ECS is a CO{sub 2} sink during the spring season. The mean difference of fCO{sub 2} (fugacity of CO{sub 2}) between the atmosphere and surface water is calculated to be 28 {mu}atm, and the resulting net CO{sub 2} invasion flux is 2.1 mol m{sup -2} yr{sup -1}, which gives about 0.03 GtC/yr of CO{sub 2} uptake in this continental shelf in spring. This study supports the notion that the shelf regions can be a significant CO{sub 2} sink. The riverine alkalinity, which discharges into ECS, is estimated to be 1,743 {mu}mol kg{sup -1} on the basis of a linear relationship between TA and salinity. The observed salinity-normalized alkalinity in ECS is higher than that in the open sea, and this excess alkalinity is estimated to be 42 {mu}mol kg{sup -1}. With the known rate of the Changjiang discharge, this excess TA gives a mean residence time of 1.2 years for the continental shelf water in the ECS. The DIC in the ECS is also found to be higher than that in the open sea. This excess DIC is estimated to be about 76 {+-} 70 {mu}mol kg{sup -1}, which is equal to a net carbon input to ECS of 3.9 {+-} 3.6 mol m{sup -2} yr{sup -1}. Based on the riverine alkalinity input, the equivalent riverine carbon flux from Changjiang discharge is estimated to be about 1.8 mol m{sup -2} yr{sup -1}. With net CO{sub 2} invasion flux of 2.1 {+-} 2.8 mol m{sup -2} yr{sup -1}, the remaining 0 {+-} 4.6 mol m{sup -2} yr{sup -1} could come from remineralization of organic matter derived from biological pump in the shelf or terrestrial sources. Although this preliminary carbon budget implies that gas exchange and riverine input are the main sources of excess carbon in ECS, the contribution of biological carbon flux can not be ruled out because of the large uncertainty

  8. Model-based estimation of the global carbon budget and its uncertainty from carbon dioxide and carbon isotope records

    Energy Technology Data Exchange (ETDEWEB)

    Kheshgi, Haroon S. [Corporate Research Laboratories, Exxon Research and Engineering Company, Annandale, New Jersey (United States); Jain, Atul K. [Department of Atmospheric Sciences, University of Illinois, Urbana (United States); Wuebbles, Donald J. [Department of Atmospheric Sciences, University of Illinois, Urbana (United States)

    1999-12-27

    A global carbon cycle model is used to reconstruct the carbon budget, balancing emissions from fossil fuel and land use with carbon uptake by the oceans, and the terrestrial biosphere. We apply Bayesian statistics to estimate uncertainty of carbon uptake by the oceans and the terrestrial biosphere based on carbon dioxide and carbon isotope records, and prior information on model parameter probability distributions. This results in a quantitative reconstruction of past carbon budget and its uncertainty derived from an explicit choice of model, data-based constraints, and prior distribution of parameters. Our estimated ocean sink for the 1980s is 17{+-}7 Gt C (90% confidence interval) and is comparable to the estimate of 20{+-}8 Gt C given in the recent Intergovernmental Panel on Climate Change assessment [Schimel et al., 1996]. Constraint choice is tested to determine which records have the most influence over estimates of the past carbon budget; records individually (e.g., bomb-radiocarbon inventory) have little effect since there are other records which form similar constraints. (c) 1999 American Geophysical Union.

  9. Carbon Budget and its Dynamics over Northern Eurasia Forest Ecosystems

    Science.gov (United States)

    Shvidenko, Anatoly; Schepaschenko, Dmitry; Kraxner, Florian; Maksyutov, Shamil

    2016-04-01

    -2012. It has been shown that the Net Ecosystem Carbon Budget (NECB) of Russian forests for this period was in range of 0.5-0.7 Pg C yr-1 with a slight negative trend during the period due to acceleration of disturbance regimes and negative impacts of weather extremes (heat waves etc.). Uncertainties of the FCA for individual years were estimated at about 25% (CI 0.9). It has been shown that some models (e.g. majority of DGVMs) do not describe some processes on permafrost satisfactory while results of applications of ensembles of inverse models on average are closed to empirical assessments. A most important conclusion from this experience is that future improvements of knowledge of carbon cycling of Northern Eurasia forests requires development of an integrated observing system as a unified information background, as well as systems methodological improvements of all methods of cognition of carbon cycling.

  10. Carbon budgets and potential blue carbon stores in Scotland's coastal and marine environment

    Science.gov (United States)

    Howe, John; austin, william

    2016-04-01

    The role of marine ecosystems in storing blue carbon has increasingly become a topic of interest to both scientists and politicians. This is the first multidisciplinary study to assess Scotland's marine blue carbon stores, using GIS to collate habitat information based on existing data. Relevant scientific information on primary habitats for carbon uptake and storage has been reviewed, and quantitative rates of production and storage were obtained. Habitats reviewed include kelp, phytoplankton, saltmarshes, biogenic reefs (including maerl), marine sediments (coastal and shelf), and postglacial geological sediments. Each habitat has been individually assessed for any specific threats to its carbon sequestration ability. Here we present an ecosystem-scale inventory of the key rates and ultimate sequestration capacity of each habitat. Coastal and offshore sediments are the main repositories for carbon in Scotland's marine environment. Habitat-forming species on the coast (seagrasses, saltmarsh, bivalve beds, coralline algae), are highly productive but their contribution to the overall carbon budget is very small because of the limited extent of each habitat. This study highlights the importance of marine carbon stores in global carbon cycles, and the implications of climate change on the ability of marine ecosystems to sequester carbon.

  11. Mitigation choices impact carbon budget size compatible with low temperature goals

    Science.gov (United States)

    Rogelj, Joeri; Reisinger, Andy; McCollum, David L.; Knutti, Reto; Riahi, Keywan; Meinshausen, Malte

    2015-07-01

    Global-mean temperature increase is roughly proportional to cumulative emissions of carbon-dioxide (CO2). Limiting global warming to any level thus implies a finite CO2 budget. Due to geophysical uncertainties, the size of such budgets can only be expressed in probabilistic terms and is further influenced by non-CO2 emissions. We here explore how societal choices related to energy demand and specific mitigation options influence the size of carbon budgets for meeting a given temperature objective. We find that choices that exclude specific CO2 mitigation technologies (like Carbon Capture and Storage) result in greater costs, smaller compatible CO2 budgets until 2050, but larger CO2 budgets until 2100. Vice versa, choices that lead to a larger CO2 mitigation potential result in CO2 budgets until 2100 that are smaller but can be met at lower costs. In most cases, these budget variations can be explained by the amount of non-CO2 mitigation that is carried out in conjunction with CO2, and associated global carbon prices that also drive mitigation of non-CO2 gases. Budget variations are of the order of 10% around their central value. In all cases, limiting warming to below 2 °C thus still implies that CO2 emissions need to be reduced rapidly in the coming decades.

  12. Simulation of carbon and water budgets of a Douglas-fir forest

    NARCIS (Netherlands)

    Wijk, van M.T.; Dekker, S.C.; Bouten, W.; Kohsiek, W.; Mohren, G.M.J.

    2001-01-01

    The forest growth/hydrology model FORGRO–SWIF, consisting of a forest growth and a soil water model, was applied to quantify the inter-annual variability of the carbon and water budgets of a Douglas-fir forest (Pseudotsuga menziessii (Mirb.) Franco) in The Netherlands. With these budgets, the water

  13. Ozone and carbon monoxide budgets over the Eastern Mediterranean

    NARCIS (Netherlands)

    Myriokefalitakis, S.; Daskalakis, N.; Fanourgakis, G.S.; Voulgarakis, A.; Krol, M.C.; Brugh, Aan de J.M.J.; Kanakidou, M.

    2016-01-01

    The importance of the long-range transport (LRT) on O3 and CO budgets over the Eastern Mediterranean has been investigated using the state-of-the-art 3-dimensional global chemistry-transport model TM4-ECPL. A 3-D budget analysis has been performed separating the Eastern from the

  14. Reviews and syntheses: Hidden forests, the role of vegetated coastal habitats in the ocean carbon budget

    KAUST Repository

    Duarte, Carlos M.

    2017-01-23

    Vegetated coastal habitats, including seagrass and macroalgal beds, mangrove forests and salt marshes, form highly productive ecosystems, but their contribution to the global carbon budget remains overlooked, and these forests remain

  15. Spatial and temporal variation in reef-scale carbonate storage of large benthic foraminifera: a case study on One Tree Reef

    Science.gov (United States)

    Doo, Steve S.; Hamylton, Sarah; Finfer, Joshua; Byrne, Maria

    2017-03-01

    Large benthic foraminifera (LBFs) are a vital component of coral reef carbonate production, often overlooked due to their small size. These super-abundant calcifiers are crucial to reef calcification by generation of lagoon and beach sands. Reef-scale carbonate production by LBFs is not well understood, and seasonal fluctuations in this important process are largely unquantified. The biomass of five LBF species in their algal flat habitat was quantified in the austral winter (July 2013), spring (October 2013), and summer (February 2014) at One Tree Reef. WorldView-2 satellite images were used to characterize and create LBF habitat maps based on ground-referenced photographs of algal cover. Habitat maps and LBF biomass measurements were combined to estimate carbonate storage across the entire reef flat. Total carbonate storage of LBFs on the reef flat ranged from 270 tonnes (winter) to 380 tonnes (summer). Satellite images indicate that the habitat area used by LBFs ranged from 0.6 (winter) to 0.71 km2 (spring) of a total possible area of 0.96 km2. LBF biomass was highest in the winter when algal habitat area was lowest, but total carbonate storage was the highest in the summer, when algal habitat area was intermediate. Our data suggest that biomass measurements alone do not capture total abundance of LBF populations (carbonate storage), as the area of available habitat is variable. These results suggest LBF carbonate production studies that measure biomass in discrete locations and single time points fail to capture accurate reef-scale production by not incorporating estimates of the associated algal habitat. Reef-scale measurements in this study can be incorporated into carbonate production models to determine the role of LBFs in sedimentary landforms (lagoons, beaches, etc.). Based on previous models of entire reef metabolism, our estimates indicate that LBFs contribute approximately 3.9-5.4% of reef carbonate budgets, a previously underappreciated carbon sink.

  16. Dissolved organic carbon concentration controls benthic primary production: results from in situ chambers in north-temperate lakes

    Science.gov (United States)

    Godwin, Sean C.; Jones, Stuart E.; Weidel, Brian C.; Solomon, Christopher T.

    2014-01-01

    We evaluated several potential drivers of primary production by benthic algae (periphyton) in north-temperate lakes. We used continuous dissolved oxygen measurements from in situ benthic chambers to quantify primary production by periphyton at multiple depths across 11 lakes encompassing a broad range of dissolved organic carbon (DOC) and total phosphorous (TP) concentrations. Light-use efficiency (primary production per unit incident light) was inversely related to average light availability (% of surface light) in 7 of the 11 study lakes, indicating that benthic algal assemblages exhibit photoadaptation, likely through physiological or compositional changes. DOC alone explained 86% of the variability in log-transformed whole-lake benthic production rates. TP was not an important driver of benthic production via its effects on nutrient and light availability. This result is contrary to studies in other systems, but may be common in relatively pristine north-temperate lakes. Our simple empirical model may allow for the prediction of whole-lake benthic primary production from easily obtained measurements of DOC concentration.

  17. Comparing simulated carbon budget of a Lei bamboo forest with flux tower data

    Science.gov (United States)

    Li, Xuehe; Jiang, Hong; Liu, Jinxun; Sun, Cheng; Wang, Ying; Jin, Jiaxin

    2014-01-01

    Bamboo forest ecosystem is the part of the forest ecosystem. The distribution area of bamboo forest is limited, but in somewhere, like south China, it has been cultivate for a long time with human management. As the climate change has been take great effect on forest carbon budget, many researchers pay attention to the carbon budget in bamboo forest. Moreover cultivative management had a significant impact on the bamboo forest carbon budget. In this study, we modified a terrestrial ecosystem model named Integrated Biosphere Simulator (IBIS) according the management of Lei bamboo forest. Some management, like fertilization, shoots harvesting and organic mulching in winter, had been incorporated into model. Then we had compared model results with the observation data from a Lei bamboo flux tower. The simulated and observed results had achieved good consistency. Our simulated Lei bamboo forest yearly net ecosystem productivity (NEP) was 0.41 kgC a-1 of carbon, which is very close to the observation data 0.45 kgC a-1 of carbon. And the monthly simulated results can take the change of carbon budget in each month, similar to the data we got from flux tower. It reflects that the modified IBIS model can characterize the growth of bamboo forest and perform the simulation well. And then two groups of simulations were set to evaluate effects of cultivative managements on Lei bamboo forests carbon budget. And results showed that both fertilization and organic mulching had taken positive effects on Lei bamboo forests carbon sequestration.

  18. Carbon flows in the benthic food web of the Porcupine Abyssal Plain: The(un)importance of labile detritus in supporting microbial and faunal carbon demands

    NARCIS (Netherlands)

    van Oevelen, D.; Soetaert, K.; Heip, C.

    2012-01-01

    Carbon flows in the benthic food web of the Porcupine Abyssal Plain (4850 m, northeast Atlantic) were reconstructed using linear inverse modeling based on mass balances of the various compartments, biomass data, carbon flux measurements, physiological constraints, and data from a previously publishe

  19. Carbon flows in the benthic food web of the Porcupine Abyssal Plain: The (un)importance of labile detritus in supporting microbial and faunal carbon demands

    NARCIS (Netherlands)

    Van Oevelen, D.; Soetaert, K.E.R.; Heip, C.H.R.

    2012-01-01

    Carbon flows in the benthic food web of the Porcupine Abyssal Plain (4850 m, northeast Atlantic) were reconstructed using linear inverse modeling based on mass balances of the various compartments, biomass data, carbon flux measurements, physiological constraints, and data from a previously publishe

  20. Carbon flows in the benthic food web of the Porcupine Abyssal Plain: The(un)importance of labile detritus in supporting microbial and faunal carbon demands

    NARCIS (Netherlands)

    van Oevelen, D.; Soetaert, K.; Heip, C.

    2012-01-01

    Carbon flows in the benthic food web of the Porcupine Abyssal Plain (4850 m, northeast Atlantic) were reconstructed using linear inverse modeling based on mass balances of the various compartments, biomass data, carbon flux measurements, physiological constraints, and data from a previously publishe

  1. Carbon flows in the benthic food web of the Porcupine Abyssal Plain: The (un)importance of labile detritus in supporting microbial and faunal carbon demands

    NARCIS (Netherlands)

    Van Oevelen, D.; Soetaert, K.E.R.; Heip, C.H.R.

    2012-01-01

    Carbon flows in the benthic food web of the Porcupine Abyssal Plain (4850 m, northeast Atlantic) were reconstructed using linear inverse modeling based on mass balances of the various compartments, biomass data, carbon flux measurements, physiological constraints, and data from a previously publishe

  2. Water-carbon Links in a Tropical Forest: How Interbasin Groundwater Flow Affects Carbon Fluxes and Ecosystem Carbon Budgets

    Energy Technology Data Exchange (ETDEWEB)

    Genereux, David [NC State University; Osburn, Christopher [NC State University; Oberbauer, Steven [Florida International University; Oviedo Vargas, Diana [NC State University; Dierick, Diego [Florida International University

    2017-03-27

    This report covers the outcomes from a quantitative, interdisciplinary field investigation of how carbon fluxes and budgets in a lowland tropical rainforest are affected by the discharge of old regional groundwater into streams, springs, and wetlands in the forest. The work was carried out in a lowland rainforest of Costa Rica, at La Selva Biological Station. The research shows that discharge of regional groundwater high in dissolved carbon dioxide represents a significant input of carbon to the rainforest "from below", an input that is on average larger than the carbon input "from above" from the atmosphere. A stream receiving discharge of regional groundwater had greatly elevated emissions of carbon dioxide (but not methane) to the overlying air, and elevated downstream export of carbon from its watershed with stream flow. The emission of deep geological carbon dioxide from stream water elevates the carbon dioxide concentrations in air above the streams. Carbon-14 tracing revealed the presence of geological carbon in the leaves and stems of some riparian plants near streams that receive inputs of regional groundwater. Also, discharge of regional groundwater is responsible for input of dissolved organic matter with distinctive chemistry to rainforest streams and wetlands. The discharge of regional groundwater in lowland surface waters has a major impact on the carbon cycle in this and likely other tropical and non-tropical forests.

  3. Carbon budgets for two Portuguese estuaries: implications for the management and conservation of coastal waters

    Directory of Open Access Journals (Sweden)

    Ana P. Oliveira

    2014-07-01

    The results presented illustrate that Tagus and Sado estuaries represent an important land/ocean boundary for carbon transformation and emission, and confirm the anthropogenic pressure that these estuaries are subject to. Carbon budgets vary markedly within and between these two estuaries reflecting the human pressure. Anthropogenic inputs, autochthonous carbon production and primary production are indicated as the main responsible for the carbon production within the estuaries. Both estuaries export carbon to the ocean and to the atmosphere. The inorganic carbon faction has a major role in the carbon budget, enriching the ocean in carbon dioxide, contributing this for the greenhouse effect. Our understanding of organic and inorganic carbon fluxes in Tagus and Sado estuaries is vital for an efficient protection and preservation of such ecosystems being helpful in limit human-caused damage and in restoring damaged estuarine/coastal ecosystems. In addition, the economic impact of the carbon fluxes to the atmosphere, estimated as €375,000 per year, creates the appropriate incentives to reduce emissions and shift them to higher-value uses. Suggesting, therefore, a coastal management re-oriented towards a more adaptive approach through the use of carbon market-based policies. This study is a contribution to the integration of coastal and global carbon cycles. However, additional efforts are required to fully merge other components subsystems, such as salt marshes, with these budgets. Moreover, a fully comprehension of the community metabolism in these estuaries will greatly improve this integration.

  4. Plumbing the global carbon cycle: Integrating inland waters into the terrestrial carbon budget

    Science.gov (United States)

    Cole, J.J.; Prairie, Y.T.; Caraco, N.F.; McDowell, W.H.; Tranvik, L.J.; Striegl, R.G.; Duarte, C.M.; Kortelainen, Pirkko; Downing, J.A.; Middelburg, J.J.; Melack, J.

    2007-01-01

    Because freshwater covers such a small fraction of the Earth's surface area, inland freshwater ecosystems (particularly lakes, rivers, and reservoirs) have rarely been considered as potentially important quantitative components of the carbon cycle at either global or regional scales. By taking published estimates of gas exchange, sediment accumulation, and carbon transport for a variety of aquatic systems, we have constructed a budget for the role of inland water ecosystems in the global carbon cycle. Our analysis conservatively estimates that inland waters annually receive, from a combination of background and anthropogenically altered sources, on the order of 1.9 Pg C y-1 from the terrestrial landscape, of which about 0.2 is buried in aquatic sediments, at least 0.8 (possibly much more) is returned to the atmosphere as gas exchange while the remaining 0.9 Pg y-1 is delivered to the oceans, roughly equally as inorganic and organic carbon. Thus, roughly twice as much C enters inland aquatic systems from land as is exported from land to the sea. Over prolonged time net carbon fluxes in aquatic systems tend to be greater per unit area than in much of the surrounding land. Although their area is small, these freshwater aquatic systems can affect regional C balances. Further, the inclusion of inland, freshwater ecosystems provides useful insight about the storage, oxidation and transport of terrestrial C, and may warrant a revision of how the modern net C sink on land is described. ?? 2007 Springer Science+Business Media, LLC.

  5. The Carbon and Oxygen Stable Isotopic Composition of Cultured Benthic Foraminifera (Bulimina aculeata).

    Science.gov (United States)

    McCorkle, D. C.; Bernhard, J. M.; Hintz, C. J.; Blanks, J. K.; Ostermann, D. R.; Shaw, T. J.; Chandler, G. T.

    2002-12-01

    To study the controls on benthic foraminiferal shell chemistry, live benthic foraminifera were collected from a 750 m site on the North Carolina continental margin. Mono-specific (Bulimina aculeata) and multi-species (B. aculeata, Discorbinella berthelotti, Cibicidoides pachyderma, Lenticulina sp., Uvigerina peregrina, Hoeglundina elegans) cultures were maintained for 4.5 months in an environmental chamber. Experimental microcosms contained a 1 mm layer of trace-metal free silica substrate, and were continuously flushed with water from a 1600 L seawater reservoir with known, constant temperature, δ18O(w), carbonate system chemistry and trace element concentrations. Each microcosm was seeded with 80-100 living foraminifera; B. aculeata was the most successful species in these cultures, with each microcosm producing hundreds of juvenile B. aculeata. We determined the stable isotopic composition of the calcite from the cultured B. aculeata, and compared these δ13C and δ18O values with the water chemistry of the microcosms, and with the shell chemistry of "free-range" B. aculeata collected and preserved from two sites on the NC and SC margin. The foraminiferal δ18O values were close to the expected δ18O of equilibrium calcite for both cultured and field B. aculeata (δ18O offsets of -0.2 +/- 0.1 ‰ and 0.0 +/- 0.1 ‰ , respectively). The δ13C values of cultured B. aculeata were 0.7 +/- 0.2 ‰ lower than microcosm dissolved inorganic carbon, with some evidence of smaller 13C depletions in older juveniles (larger specimens). The foram-bottom water δ13C offsets were larger for the field specimens (-0.8 ‰ at a 200 m site, and -1.4 ‰ at the 750 m site). These results suggest that the δ13C values of B. aculeata include both "vital" effects (the offset observed in cultured specimens) and microhabitat effects (the additional offset observed in field specimens).

  6. Stable carbon and oxygen isotope study on benthic foraminifera: Implication for microhabitat preferences and interspecies correlation

    Indian Academy of Sciences (India)

    Ajoy K Bhaumik; Shiv Kumar; Shilpi Ray; G K Vishwakarma; Anil K Gupta; Pushpendra Kumar; Kalachand Sain

    2017-07-01

    Stable isotopes of benthic foraminifera have widely been applied in micropalaeontological research to understand vital effects in foraminifera. Isotopic fractionations are mainly controlled by ontogeny, bottom/pore water chemistry, habitat preference, kinetic effect and respiration. Discontinuous abundance of a species for isotopic analysis has forced us to select multiple species from down-core samples. Thus standardisation factors are required to convert isotopic values of one species with respect to other species. The present study is pursued on isotopic values of different pairs of benthic foraminifera from the Krishna–Godavari basin and Peru offshore to understand habitat-wise isotopic variation and estimation of isotopic correction factors for the paired species (Cibicides wuellerstorfi–Bulimina marginata, Ammonia spp.–Loxostomum amygdalaeformis and Bolivina seminuda–Nonionella auris). Infaunal species (B. marginata, Ammonia spp. and N. auris) show a lighter carbon isotopic excursion with respect to the epifaunal to shallow infaunal forms (C. wuellerstorfi, L. amygdalaeformis and B. seminuda). These lighter δ13C values are related to utilisation of CO2 produced by anaerobic remineralisation of organic matter. However, enrichment of δ18O for the deeper microhabitat (bearing lower pH and decreased CO32−) is only recorded in case of B. marginata. It is reverse in case of N. auris and related to utilisation of respiratory CO2 and internal dissolve inorganic carbon pool. Estimation of interspecies isotopic correction factors for the species pairs (δ13C of C. wuellerstorfi–B. marginata, L. amygdalaeformis–Ammonia spp., N. auris–B. seminuda) and δ18O of C. wuellerstorfi–B. marginata are statistically reliable and may be used in palaeoecological studies.

  7. Carbon Budget for Basic Needs: Implications of International Equity and Sustainability%Carbon Budget for Basic Needs: Implications of International Equity and Sustainability

    Institute of Scientific and Technical Information of China (English)

    Pan Jiahua

    2011-01-01

    The fundamental way of satisfying the basic needs of human development is to secure the basic needs, limit luxurious and wasteful emissions, and ensure the fulfillment of climate targets, so as to achieve intra- and intergenerational equity. In this paper, the author discusses and analyzes a series of challenges that the development has to face, such as poverty elimination, urbanization, and industrialization, and the problems of increased consumption that is brought about by the improvement of living standards; the author distinguishes the stock emission, which does not need annual updating, and the flow emission of regular consumption; the author also defines the standards of energy consumption and carbon emissions that can meet the basic needs. On this basis, the author proposes the concept and method of carbon budget, compares this method with other means, and in particular, studies and analyzes the implications of international equity and sustainability of carbon budget as part of the international climate regime design.

  8. Calibration of the carbonate `clumped isotope' paleotemperature proxy using mollusc shells and benthic foraminiferal tests

    Science.gov (United States)

    Came, R. E.; Curry, W. B.; Weidman, C. R.; Eiler, J. M.

    2007-12-01

    It has recently been shown that the carbonate `clumped isotope' thermometer can provide temperature constraints that depend only on the isotopic composition of carbonate (in particular, on the proportion of 13C and 18O that form bonds with each other), and that do not require assumptions about the isotopic composition of the water in which the carbonate formed (Ghosh et al., 2006). Furthermore, this novel method permits the calculation of seawater δ18O based on the clumped isotope temperature estimates and the simultaneously obtained δ18O of carbonate, thereby enabling the extraction of global ice volume estimates for both the recent and distant geologic past. Here we present clumped isotope analyses of several naturally occurring marine carbonates that calcified at known temperatures in the modern ocean. First, we analyzed benthic foraminiferal tests from six high-quality multicore tops collected in the Florida Strait, spanning a temperature range of 9.3-20.2 degrees C. Second, we analyzed shallow-water mollusc shells from a variety of different climate regimes, spanning a temperature range of 2.5-26.0 degrees C. We find that the calcitic foraminiferal species Cibicidoides spp. agrees well with the inorganic calcite precipitation experiments of Ghosh et al. (2006), while the aragonitic species Hoeglundina elegans is significantly offset. Similarly, clumped isotope results obtained from aragonitic mollusc shells also reveal an offset from the Ghosh et al. (2006) trend, although the offset observed in mollusc aragonite is quite different in nature from that observed in foraminiferal aragonite. Assuming our estimates of the growth temperatures of these naturally occurring organisms are correct, these results suggest that there are vital effects associated with the stable isotope compositions of the aragonite-precipitating organisms examined in this study; further work will be required to determine their cause. Nevertheless, the internal coherence of trends for

  9. Mangrove production and carbon sinks: a revision of global budget estimates

    NARCIS (Netherlands)

    Bouillon, S.; Borges, A.V.; Castañeda-Moya, E.; Diele, K.; Dittmar, T.; Duke, N.C.; Kristensen, E.; Lee, S.; Marchand, C.; Middelburg, J.J.; Rivera-Monroy, V.H.; Smith III, T.; Twilley, R.R.

    2008-01-01

    Mangrove forests are highly productive but globally threatened coastal ecosystems, whose role in the carbon budget of the coastal zone has long been debated. Here we provide a comprehensive synthesis of the available data on carbon fluxes in mangrove ecosystems. A reassessment of global mangrove pri

  10. Top-down assessment of the Asian carbon budget since the mid 1990s

    NARCIS (Netherlands)

    Thompson, R.L.; Patra, P.K.; Chevallier, F.; Maksyutov, S.; Law, R.M.; Ziehn, T.; Laan-Luijkx, Van Der I.T.; Peters, W.; Ganshin, A.; Zhuravlev, R.; Maki, T.; Nakamura, T.; Shirai, T.; Ishizawa, M.; Saeki, T.; Machida, T.; Poulter, B.; Canadell, J.G.; Ciais, P.

    2016-01-01

    Increasing atmospheric carbon dioxide (CO2) is the principal driver of anthropogenic climate change. Asia is an important region for the global carbon budget, with 4 of the world's 10 largest national emitters of CO2. Using an ensemble of seven atmospheric inverse systems, w

  11. Closing the carbon budget of a Scots pine forest in the Netherlands

    NARCIS (Netherlands)

    Schelhaas, M.J.; Nabuurs, G.J.; Jans, W.W.P.; Moors, E.J.; Sabaté, S.; Daamen, W.P.

    2004-01-01

    The aim of this study was to close the carbon budget and reduce uncertainty in annual C balances for Scots pine (Pinus sylvestris) forests in The Netherlands. This was done by comparing estimates of the Net Ecosystem Exchange (NEE) as assessed by two different methods. The inventory based carbon bud

  12. Reviews and syntheses: Hidden forests, the role of vegetated coastal habitats in the ocean carbon budget

    Science.gov (United States)

    Duarte, Carlos M.

    2017-01-01

    Vegetated coastal habitats, including seagrass and macroalgal beds, mangrove forests and salt marshes, form highly productive ecosystems, but their contribution to the global carbon budget remains overlooked, and these forests remain hidden in representations of the global carbon budget. Despite being confined to a narrow belt around the shoreline of the world's oceans, where they cover less than 7 million km2, vegetated coastal habitats support about 1 to 10 % of the global marine net primary production and generate a large organic carbon surplus of about 40 % of their net primary production (NPP), which is either buried in sediments within these habitats or exported away. Large, 10-fold uncertainties in the area covered by vegetated coastal habitats, along with variability about carbon flux estimates, result in a 10-fold bracket around the estimates of their contribution to organic carbon sequestration in sediments and the deep sea from 73 to 866 Tg C yr-1, representing between 3 % and 1/3 of oceanic CO2 uptake. Up to 1/2 of this carbon sequestration occurs in sink reservoirs (sediments or the deep sea) beyond these habitats. The organic carbon exported that does not reach depositional sites subsidizes the metabolism of heterotrophic organisms. In addition to a significant contribution to organic carbon production and sequestration, vegetated coastal habitats contribute as much to carbonate accumulation as coral reefs do. While globally relevant, the magnitude of global carbon fluxes supported by salt-marsh, mangrove, seagrass and macroalgal habitats is declining due to rapid habitat loss, contributing to loss of CO2 sequestration, storage capacity and carbon subsidies. Incorporating the carbon fluxes' vegetated coastal habitats' support into depictions of the carbon budget of the global ocean and its perturbations will improve current representations of the carbon budget of the global ocean.

  13. Estimation of future carbon budget with climate change and reforestation scenario in North Korea

    Science.gov (United States)

    Kim, Damin; Lim, Chul-Hee; Song, Cholho; Lee, Woo-Kyun; Piao, Dongfan; Heo, Seongbong; Jeon, Seongwoo

    2016-09-01

    In terms of climate change, quantifying carbon budget in forest is critical for managing a role of forest as carbon sink. Deforestation in North Korea has been exacerbating at a noticeable pace and caused to worsen the carbon budget. Under the circumstance, this study aimed to assess the impact of climate change and reforestation on the carbon budget in 2020s and 2050s, using the VISIT (Vegetation Integrative SImulator for Trace gases) model. In order to analyze the impact of reforestation, future land cover maps for the 2020s and 2050s were prepared. Among the deforested areas (2.5 × 106 ha) identified by comparing land cover maps for different periods, the potential reforestation areas were selected by a reforestation scenario considering slope, accessibility from residence, and deforestation types. The extracted potential reforestation areas were 1.7 × 106 ha and the increased forest area was spatially distributed to each district. The percentage change in carbon budget caused by climate change from the 2000s to 2020s is 67.60% and that from the 2020s to 2050s is 45.98% on average. Based on the future land cover, NEP (net ecosystem production) with reforestation will increase by 18.18% than that without reforestation in the 2050s, which shows the contribution to carbon balance. In connection with this long term projection, it is revealed that the gross fluxes such as photosynthesis and respiration may be impacted more obviously by the climate change, especially global warming, than the net carbon flux because of the offset between the changes in the gross fluxes. It is analyzed that changes in carbon budget are very sensitive to climate changes, while the impact of reforestation is relatively less sensitive. Although it is impossible to significantly improve carbon sequestration by establishing forest in a short-term, reforestation is imperative in a long-term view as it clearly has a potential mechanism to offset emitted carbon.

  14. Linking Intertidal and Subtidal Food Webs: Consumer-Mediated Transport of Intertidal Benthic Microalgal Carbon.

    Science.gov (United States)

    Kang, Chang-Keun; Park, Hyun Je; Choy, Eun Jung; Choi, Kwang-Sik; Hwang, Kangseok; Kim, Jong-Bin

    2015-01-01

    We examined stable carbon and nitrogen isotope ratios for a large variety of consumers in intertidal and subtidal habitats, and their potential primary food sources [i.e., microphytobenthos (MPB), phytoplankton, and Phragmites australis] in a coastal bay system, Yeoja Bay of Korea, to test the hypothesis that the transfer of intertidal MPB-derived organic carbon to the subtidal food web can be mediated by motile consumers. Compared to a narrow δ13C range (-18 to -16‰) of offshore consumers, a broad δ13C range (-18 to -12‰) of both intertidal and subtidal consumers indicated that 13C-enriched sources of organic matter are an important trophic source to coastal consumers. In the intertidal areas, δ13C of most consumers overlapped with or was 13C-enriched relative to MPB. Despite the scarcity of MPB in the subtidal, highly motile consumers in subtidal habitat had nearly identical δ13C range with many intertidal foragers (including crustaceans and fish), overlapping with the range of MPB. In contrast, δ13C values of many sedentary benthic invertebrates in the subtidal areas were similar to those of offshore consumers and more 13C-depleted than motile foragers, indicating high dependence on phytoplankton-derived carbon. The isotopic mixing model calculation confirms that the majority of motile consumers and also some of subtidal sedentary ones depend on intertidal MPB for more than a half of their tissue carbon. Finally, although further quantitative estimates are needed, these results suggest that direct foraging by motile consumers on intertidal areas, and thereby biological transport of MPB-derived organic carbon to the subtidal areas, may provide important trophic connection between intertidal production and the nearshore shallow subtidal food webs.

  15. Linking Intertidal and Subtidal Food Webs: Consumer-Mediated Transport of Intertidal Benthic Microalgal Carbon.

    Directory of Open Access Journals (Sweden)

    Chang-Keun Kang

    Full Text Available We examined stable carbon and nitrogen isotope ratios for a large variety of consumers in intertidal and subtidal habitats, and their potential primary food sources [i.e., microphytobenthos (MPB, phytoplankton, and Phragmites australis] in a coastal bay system, Yeoja Bay of Korea, to test the hypothesis that the transfer of intertidal MPB-derived organic carbon to the subtidal food web can be mediated by motile consumers. Compared to a narrow δ13C range (-18 to -16‰ of offshore consumers, a broad δ13C range (-18 to -12‰ of both intertidal and subtidal consumers indicated that 13C-enriched sources of organic matter are an important trophic source to coastal consumers. In the intertidal areas, δ13C of most consumers overlapped with or was 13C-enriched relative to MPB. Despite the scarcity of MPB in the subtidal, highly motile consumers in subtidal habitat had nearly identical δ13C range with many intertidal foragers (including crustaceans and fish, overlapping with the range of MPB. In contrast, δ13C values of many sedentary benthic invertebrates in the subtidal areas were similar to those of offshore consumers and more 13C-depleted than motile foragers, indicating high dependence on phytoplankton-derived carbon. The isotopic mixing model calculation confirms that the majority of motile consumers and also some of subtidal sedentary ones depend on intertidal MPB for more than a half of their tissue carbon. Finally, although further quantitative estimates are needed, these results suggest that direct foraging by motile consumers on intertidal areas, and thereby biological transport of MPB-derived organic carbon to the subtidal areas, may provide important trophic connection between intertidal production and the nearshore shallow subtidal food webs.

  16. Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya

    Directory of Open Access Journals (Sweden)

    S. Bouillon

    2004-01-01

    Full Text Available The origin of carbon substrates used by in situ sedimentary bacterial communities was investigated in an intertidal mangrove ecosystem and in adjacent seagrass beds in Gazi bay (Kenya by δ13C analysis of bacteria-specific PLFA (phospholipid fatty acids and bulk organic carbon. Export of mangrove-derived organic matter to the adjacent seagrass-covered bay was evident from sedimentary total organic carbon (TOC and δ13CTOC data. PLFA δ13C data indicate that the substrate used by bacterial communities varied strongly and that exported mangrove carbon was a significant source for bacteria in the adjacent seagrass beds. Within the intertidal mangrove forest, bacterial PLFA at the surface layer (0-1cm typically showed more enriched δ13C values than deeper (up to 10cm sediment layers, suggesting a contribution from microphytobenthos and/or inwelled seagrass material. Under the simplifying assumption that seagrasses and mangroves are the dominant potential end-members, the estimated contribution of mangrove-derived carbon to benthic mineralization in the seagrass beds (16-74% corresponds fairly well to the estimated contribution of mangrove C to the sedimentary organic matter pool (21-71% across different seagrass sites. Based on the results of this study and a compilation of literature data, we suggest that trapping of allochtonous C is a common feature in seagrass beds and often represents a significant source of C for sediment bacteria - both in cases where seagrass C dominates the sediment TOC pool and in cases where external inputs are significant. Hence, it is likely that data on community respiration rates systematically overestimate the role of in situ mineralization as a fate of seagrass production.

  17. Workshop on assessments of National Carbon Budgets within the Nordic Region

    DEFF Research Database (Denmark)

    Mørk, Eva Thorborg; Lansø, Anne Sofie; Hansen, Kristina

    2013-01-01

    research in the field and following scientific discussions, the workshop contributed to strengthen the scientific basis of the identification and quantification of major natural carbon sinks in the Nordic region on which integrated climate change abatement and management strategies and policy decisions...... status and knowledge on research on assessments of national carbon budgets as well as on projections and sensitivity to future changes in e.g. management and climate change in the Nordic Region....... is formed from. This report summarizes presentations and discussions from the four thematic sessions; Observations of carbon sinks and sources, Modeling the carbon budget, Remote sensing data for carbon modeling, and Impacts of future climate and land use scenarios and gives an overview of the current...

  18. Carbon budgets of thirteen years at the FLUXNET cropland site Oensingen, Switzerland

    Science.gov (United States)

    Emmel, Carmen; Revill, Andrew; Hörtnagl, Lukas; Eugster, Werner

    2017-04-01

    The FLUXNET cropland site at Oensingen, Switzerland (CH-Oe2) is located on the Swiss Plateau, which is representative for the average domain of agricultural crop production in Switzerland. The site is managed under the low pesticide integrated production (IP) farming protocol and features a crop rotation focusing on winter wheat, but also includes winter barley, rapeseed, peas and potatoes as well as intermediate cover crops. Thirteen years of eddy covariance and meteorological measurements are available for the site. The carbon imports through manure applications and sowing, along with the exports through harvests, were quantified. In this study, we analyze the carbon budgets of all crop types and measurement years. These results will be compared to changes in soil carbon content. We will answer the questions: (1) Has the crop rotation and field management resulted in a net carbon source or sink? (2) To what extent are the different crop types linked to net carbon exchanges? (3) What are the climatic potential drivers for the interannual cropland carbon budget? (4) Is the carbon budget reflected in the changes in soil carbon content?

  19. Closing the Carbon Budget in Perennial Biofuel Crops

    Science.gov (United States)

    Kantola, I. B.; Anderson-Teixeira, K. J.; Bernacchi, C.; Hudiburg, T. W.; Masters, M. D.; DeLucia, E. H.

    2013-12-01

    At present, some 40% of corn grown in the United States, accounting for more than 26 million acres of farmland, is processed for bioethanol. Interest has arisen in converting biofuel production from corn grain ethanol to cellulosic ethanol, derived primarily from cellulose from dedicated energy crops. As many cellulosic biofuel feedstocks are perennial grasses, conversion from annual corn cropping to perennials represents a substantial change in farming practices with the potential to alter the plant-soil relationship in the Midwestern United States. Elimination of annual tillage preserves soils structure, conserving soil carbon and maintaining plant root systems. Five years of perennial grass establishment in former agricultural land in Illinois has shown a significant change in soil carbon pools and fluxes. Atmospheric carbon exchange monitoring combined with vegetation and soil sampling and respiration measurements confirm that in the first 3 years (establishment phase), perennial giant grasses Miscanthus x giganteus and Panicum virgatum rapidly increased belowground carbon allocation >400% and belowground biomass 400-750% compared to corn. Following establishment, perennial grasses maintained below- and aboveground annual biomass production, out-performing corn in both average and drought conditions. Here we offer a quantitative comparison of the carbon allocation pathways of corn and perennial biofuel crops in Midwestern landscapes, demonstrating the carbon benefits of perennial cropping through increased C allocation to root and rhizome structures. Long rotation periods in perennial grasses combined with annual carbon inputs to the soil system are expected to convert these agricultural soils from atmospheric carbon sources to carbon sinks.

  20. Calculating carbon budgets of wind farms on Scottish peatlands

    Directory of Open Access Journals (Sweden)

    D.R. Nayak

    2010-04-01

    Full Text Available The reliability of calculation methods for the carbon emission savings to be achieved in Scotland by replacing power generated from fossil fuels (and other more conventional sources with that produced by large-scale wind farm developments is a cause for concern, largely in relation to wind farms sited on peatlands. Scottish Government policy is to deliver renewable energy without environmental harm, and to meet biodiversity objectives including the conservation of designated wildlife sites and important habitats such as peatlands. The implications for carbon emissions of developing a wind farm are, therefore, just one aspect of the suite of considerations that the planning system takes into account. This paper presents a simple methodology for prospectively calculating the potential carbon emission savings to be realised by developing wind farms on peatland, forestland or afforested peatland. The total carbon emission savings of an individual wind farm are estimated by accounting emissions from the power source that will be replaced by wind power against: loss of carbon due to production, transportation, erection, operation and dismantling of the wind farm components (the infrastructure overhead; loss of carbon due to backup power generation; loss of carbon stored in peat and forest; loss of carbon-fixing potential of peatland and forest; and carbon savings due to habitat improvement. Most of the carbon losses are determined by national infrastructure, but those from peat soil and plants are influenced by site selection and management practices. The extent of drainage around each constructed element of the wind farm is a major factor for greenhouse gas emissions. Consideration of an example site with a low extent of drainage, where management practices that minimise net carbon losses (e.g. undrained floating roads, habitat improvement and site restoration on decommissioning were used indicates that emissions from the soil and plants may cancel

  1. Boron Isotopes in Benthic Foraminifera by MC-ICPMS: Unlocking the Ocean's Carbon Cycle

    Science.gov (United States)

    Rae, J. W.; Foster, G. L.; Schmidt, D. N.; Elliott, T. R.

    2008-12-01

    The cause of glacial-interglacial CO2 cycles has been described as the "holy grail" of climate science. All models currently proposed invoke changes in deep ocean carbon storage, but the mechanisms by which this took place remain unclear. Proxies for two components of the ocean carbonate system would allow us to fully reconstruct ocean carbonate equilibria and trace the spatial and temporal pattern of glacial carbon storage, providing valuable constraints on the causal mechanisms of atmospheric CO2 change. The theory behind the boron isotope pH proxy is well understood, but its reliability has been questioned, primarily due to uncertainty in the fractionation factor between boron species in seawater, and analytical difficulties associated with negative thermal ionisation (NTIMS) measurements. We have developed a new technique for boron isotopic analysis by multicollector inductively coupled plasma mass spectrometry (MC- ICPMS), which overcomes many of the problems associated with NTIMS measurements. Our method is precise (better than 0.25%, or ~0.02 pH units, on full procedural replicates at 95% confidence), rapid (allowing duplicate measurement of 10-20 samples per analytical session), and has small sample size requirements of ~10 ng boron (~0.5 mg foraminiferal tests). As MC-ICPMS analysis requires separation of boron prior to measurement, any bias between samples and standards with different matrices is also removed. Recent experimental work has also improved uncertainty in the isotopic fractionation factor (now measured at 1.0272 ±0.0006 [1]), providing a powerful independent means to test the behaviour of the foram-based δ11B proxy, and its ability to provide absolute pH values. We have measured δ11B in several species of benthic foraminifera from a range of core-top samples. In contrast to previous studies, we find a very close match between foraminiferal δ11B values and the δ11B of seawater B(OH)4- - predicted using the recently determined fractionation

  2. The Human Carbon Budget: An Estimate of the Spatial Distribution of Metabolic Carbon Consumption and Release in the United States

    Energy Technology Data Exchange (ETDEWEB)

    West, Tristram O. [ORNL; Singh, Nagendra [ORNL; Marland, Gregg [ORNL; Bhaduri, Budhendra L [ORNL

    2009-01-01

    Carbon dioxide is taken up by agricultural crops and released soon after during the consumption of agricultural commodities. The global net impact of this process on carbon flux to the atmosphere is negligible, but impact on the spatial distribution of carbon dioxide uptake and release across regions and continents is significant. To estimate the consumption and release of carbon by humans over the landscape, we developed a carbon budget for humans in the United States. The budget was derived from food commodity intake data for the US and from algorithms representing the metabolic processing of carbon by humans. Data on consumption, respiration, and waste of carbon by humans were distributed over the US using geospatial population data with a resolution of approximately 450 x 450 m. The average adult in the US contains about 21 kg C and consumes about 67 kg C yr-1 which is balanced by the annual release of about 59 kg C as expired CO2, 7 kg C as feces and urine, and less than 1 kg C as flatus, sweat, and aromatic compounds. In 2000, an estimated 17.2 Tg C were consumed by the US population and 15.2 Tg C were expired to the atmosphere as CO2. Historically, carbon stock in the US human population has increased between 1790-2006 from 0.06 Tg to 5.37 Tg. Displacement and release of total harvested carbon per capita in the US is nearly 12% of per capita fossil fuel emissions. Humans are using, storing, and transporting carbon about the Earth s surface. Inclusion of these carbon dynamics in regional carbon budgets can improve our understanding of carbon sources and sinks.

  3. Reef Habitat Type and Spatial Extent as Interacting Controls on Platform-Scale Carbonate Budgets

    Directory of Open Access Journals (Sweden)

    Chris T. Perry

    2017-06-01

    Full Text Available A coral reefs carbonate budget strongly influences reef structural complexity and net reef growth potential, and thus is increasingly recognized as a key “health” metric. Despite this, understanding of habitat specific budget states, how these scale across reef platforms, and our ability to quantify both framework and sediment production values remains limited. Here, we use in-situ census data from an atoll rim reef platform in the central Maldives to quantify rates of both reef framework and sediment production and loss within different platform habitats, and then combine these data with high-resolution habitat maps to quantify contributions to platform wide carbonate budgets. The net reef framework budget for the entire platform is extremely low (0.12 G, where G = Kg CaCO3 m−2 year−1, with a very high proportion (143,745 kg or 65.1% of total framework production generated within the platform margin reef zones, despite these comprising only ~8% of platform area. Net platform-scale sediment budgets are higher (1.04 G, but most is produced in the reef and platform margin hardground habitats, of which ~80% derives from parrotfish bioerosion. Significant quantities of new sediment (up to ~1 G derived from the calcareous green algae Halimeda are produced only in one habitat. All lagoonal habitats have negative or neutral net carbonate budgets. These data demonstrate the marked inter-habitat differences in reef carbonate budgets that occur across reef platforms, and the major dampening effect on overall platform scale budgets when rates are factored for habitat type and size. Furthermore, the data highlights the disproportionately important role that relatively small areas of reef habitat can have on the maintenance of net positive platform scale budgets. Because of the intrinsic link between carbonate production rates and reef-associated landform development and maintenance, these findings also have implications for understanding reef

  4. Ozone and carbon monoxide budgets over the Eastern Mediterranean.

    Science.gov (United States)

    Myriokefalitakis, S; Daskalakis, N; Fanourgakis, G S; Voulgarakis, A; Krol, M C; Aan de Brugh, J M J; Kanakidou, M

    2016-09-01

    The importance of the long-range transport (LRT) on O3 and CO budgets over the Eastern Mediterranean has been investigated using the state-of-the-art 3-dimensional global chemistry-transport model TM4-ECPL. A 3-D budget analysis has been performed separating the Eastern from the Western basins and the boundary layer (BL) from the free troposphere (FT). The FT of the Eastern Mediterranean is shown to be a strong receptor of polluted air masses from the Western Mediterranean, and the most important source of polluted air masses for the Eastern Mediterranean BL, with about 40% of O3 and of CO in the BL to be transported from the FT aloft. Regional anthropogenic sources are found to have relatively small impact on regional air quality in the area, contributing by about 8% and 18% to surface levels of O3 and CO, respectively. Projections using anthropogenic emissions for the year 2050 but neglecting climate change calculate a surface O3 decrease of about 11% together with a surface CO increase of roughly 10% in the Eastern Mediterranean.

  5. Scenario analysis of the impacts of forest management and climate change on the European forest sector carbon budget

    NARCIS (Netherlands)

    Karjalainen, T.; Pusinen, A.; Liski, J.; Nabuurs, G.J.; Eggers, T.; Lapveteläinen, T.; Kaipainen, T.

    2003-01-01

    Analysis of the impacts of forest management and climate change on the European forest sector carbon budget between 1990 and 2050 are presented in this article. Forest inventory based carbon budgeting with large scale scenario modelling was used. Altogether 27 countries and 128.5 million hectare of

  6. Workshop on assessments of National Carbon Budgets within the Nordic Region

    DEFF Research Database (Denmark)

    Mørk, Eva Thorborg; Lansø, Anne Sofie; Hansen, Kristina;

    2013-01-01

    research in the field and following scientific discussions, the workshop contributed to strengthen the scientific basis of the identification and quantification of major natural carbon sinks in the Nordic region on which integrated climate change abatement and management strategies and policy decisions...... is formed from. This report summarizes presentations and discussions from the four thematic sessions; Observations of carbon sinks and sources, Modeling the carbon budget, Remote sensing data for carbon modeling, and Impacts of future climate and land use scenarios and gives an overview of the current...

  7. Workshop on assessments of National Carbon Budgets within the Nordic Region

    DEFF Research Database (Denmark)

    Hansen, Kristina; Koyama, Aki; Lansø, Anne Sofie;

    research in the field and following scientific discussions, the workshop contributed to strengthen the scientific basis of the identification and quantification of major natural carbon sinks in the Nordic region on which integrated climate change abatement and management strategies and policy decisions...... is formed from. This report summarizes presentations and discussions from the four thematic sessions; Observations of carbon sinks and sources, Modeling the carbon budget, Remote sensing data for carbon modeling, and Impacts of future climate and land use scenarios and gives an overview of the current...

  8. Mangrove production and carbon sinks: A revision of global budget estimates

    Science.gov (United States)

    Bouillon, S.; Borges, A.V.; Castaneda-Moya, E.; Diele, K.; Dittmar, T.; Duke, N.C.; Kristensen, E.; Lee, S.-Y.; Marchand, C.; Middelburg, J.J.; Rivera-Monroy, V. H.; Smith, T. J.; Twilley, R.R.

    2008-01-01

    Mangrove forests are highly productive but globally threatened coastal ecosystems, whose role in the carbon budget of the coastal zone has long been debated. Here we provide a comprehensive synthesis of the available data on carbon fluxes in mangrove ecosystems. A reassessment of global mangrove primary production from the literature results in a conservative estimate of ???-218 ?? 72 Tg C a-1. When using the best available estimates of various carbon sinks (organic carbon export, sediment burial, and mineralization), it appears that >50% of the carbon fixed by mangrove vegetation is unaccounted for. This unaccounted carbon sink is conservatively estimated at ??? 112 ?? 85 Tg C a-1, equivalent in magnitude to ??? 30-40% of the global riverine organic carbon input to the coastal zone. Our analysis suggests that mineralization is severely underestimated, and that the majority of carbon export from mangroves to adjacent waters occurs as dissolved inorganic carbon (DIC). CO2 efflux from sediments and creek waters and tidal export of DIC appear to be the major sinks. These processes are quantitatively comparable in magnitude to the unaccounted carbon sink in current budgets, but are not yet adequately constrained with the limited published data available so far. Copyright 2008 by the American Geophysical Union.

  9. Comparative assessment of Japan's long-term carbon budget under different effort-sharing principles

    NARCIS (Netherlands)

    Kuramochi, Takeshi; Asuka, Jusen; Fekete, Hanna; Tamura, Kentaro; Höhne, Niklas

    2016-01-01

    This article assesses Japan's carbon budgets up to 2100 in the global efforts to achieve the 2 °C target under different effort-sharing approaches based on long-term GHG mitigation scenarios published in 13 studies. The article also presents exemplary emission trajectories for Japan to stay withi

  10. Comparative assessment of Japan's long-term carbon budget under different effort-sharing principles

    NARCIS (Netherlands)

    Kuramochi, Takeshi; Asuka, Jusen; Fekete, Hanna; Tamura, Kentaro; Höhne, Niklas

    2015-01-01

    This article assesses Japan's carbon budgets up to 2100 in the global efforts to achieve the 2 °C target under different effort-sharing approaches based on long-term GHG mitigation scenarios published in 13 studies. The article also presents exemplary emission trajectories for Japan to stay withi

  11. The carbon budget of the northern cryosphere region

    Science.gov (United States)

    A. David McGuire; Robie W. Macdonald; Edward A.G. Schuur; Jennifer W. Harden; Peter Kuhry; Daniel J. Hayes; Torben R. Christensen; Martin. Heimann

    2010-01-01

    The northem cryosphere is undergoing substantial warming of permafrost and loss of sea ice. Release of stored carbon to the atmosphere in response to this change has the potential to affect the global climate system. Studies indicate that the northern cryosphere has been not only a substantial sink for atmospheric CO2 in recent decades, but also...

  12. Management effects on net ecosystem carbon and GHG budgets at European crop sites

    DEFF Research Database (Denmark)

    Ceschia, Eric; Bêziat, P; Dejoux, J.F.

    2010-01-01

    . The variability of the different terms and their relative contributions to the net ecosystem carbon budget (NECB) were analysed for all site-years, and the effect of management on NECB was assessed. To account for greenhouse gas (GHG) fluxes that were not directly measured on site, we estimated the emissions......, and more studies are needed to assess the effects of management on crop efficiency.......The greenhouse gas budgets of 15 European crop sites covering a large climatic gradient and corresponding to 41 site-years were estimated. The sites included a wide range of management practices (organic and/or mineral fertilisation, tillage or ploughing, with or without straw removal...

  13. Determination of the carbon budget of a pasture: effect of system boundaries and flux uncertainties

    Science.gov (United States)

    Felber, Raphael; Bretscher, Daniel; Münger, Andreas; Neftel, Albrecht; Ammann, Christof

    2016-05-01

    Carbon (C) sequestration in the soil is considered as a potential important mechanism to mitigate greenhouse gas (GHG) emissions of the agricultural sector. It can be quantified by the net ecosystem carbon budget (NECB) describing the change of soil C as the sum of all relevant import and export fluxes. NECB was investigated here in detail for an intensively grazed dairy pasture in Switzerland. Two budget approaches with different system boundaries were applied: NECBtot for system boundaries including the grazing cows and NECBpast for system boundaries excluding the cows. CO2 and CH4 exchange induced by soil/vegetation processes as well as direct emissions by the animals were derived from eddy covariance measurements. Other C fluxes were either measured (milk yield, concentrate feeding) or derived based on animal performance data (intake, excreta). For the investigated year, both approaches resulted in a small near-neutral C budget: NECBtot -27 ± 62 and NECBpast 23 ± 76 g C m-2 yr-1. The considerable uncertainties, depending on the approach, were mainly due to errors in the CO2 exchange or in the animal-related fluxes. The comparison of the NECB results with the annual exchange of other GHG revealed CH4 emissions from the cows to be the major contributor in terms of CO2 equivalents, but with much lower uncertainty compared to NECB. Although only 1 year of data limit the representativeness of the carbon budget results, they demonstrate the important contribution of the non-CO2 fluxes depending on the chosen system boundaries and the effect of their propagated uncertainty in an exemplary way. The simultaneous application and comparison of both NECB approaches provides a useful consistency check for the carbon budget determination and can help to identify and eliminate systematic errors.

  14. [Response of Straw and Straw Biochar Returning to Soil Carbon Budget and Its Mechanism].

    Science.gov (United States)

    Hou, Ya-hong; Wang, Lei; Fu, Xiao-hua; Le, Yi-quan

    2015-07-01

    Direct straw returning and straw carbonization returning are the main measures of straw returning. Because of the differences in structure and nature as well as returning process between straw and straw biochar, the soil respiration and soil carbon budget after returning must have significant differences. In this study, outdoor pot experiment was carried out to study the response of soil respiration and carbon budget to straw and straw biochar returning and its possible mechanism. The results showed that soil respiration of straw biochar returning [mean value 21. 69 µmol.(m2.s)-1] was significantly lower than that of direct straw returning [mean value 65.32 µmol.(m2.s)-1], and its soil organic carbon content ( mean value 20. 40 g . kg-1) and plant biomass (mean value 138. 56 g) were higher than those of direct straw returning (mean values 17. 76 g . kg-1 and 76. 76 g). Considering the carbon loss after the biochar preparation process, its soil carbon budget was also significantly higher than that of direct straw returning, so it was a low carbon mode of straw returning. Direct straw returning significantly promoted soil dehydrogenase activity, soil β-glycosidase activity and soil microorganism quantity, leading to higher soil respiration, but straw biochar did play an obvious role in promoting the microbial activity index. Easily oxidizable carbon (EOC) and biodegradability of straw biochar were lower than those of straw, which showed that straw biochar had higher stability, and was more difficult to degrade for soil microorganisms so its soil microbial activity was generally lower, and could be retained in the soil for a long time.

  15. Biomineralization of Schlumbergerella floresiana, a significant carbonate-producing benthic foraminifer.

    Science.gov (United States)

    Sabbatini, A; Bédouet, L; Marie, A; Bartolini, A; Landemarre, L; Weber, M X; Gusti Ngurah Kade Mahardika, I; Berland, S; Zito, F; Vénec-Peyré, M-T

    2014-07-01

    Most foraminifera that produce a shell are efficient biomineralizers. We analyzed the calcitic shell of the large tropical benthic foraminifer Schlumbergerella floresiana. We found a suite of macromolecules containing many charged and polar amino acids and glycine that are also abundant in biomineralization proteins of other phyla. As neither genomic nor transcriptomic data are available for foraminiferal biomineralization yet, de novo-generated sequences, obtained from organic matrices submitted to ms blast database search, led to the characterization of 156 peptides. Very few homologous proteins were matched in the proteomic database, implying that the peptides are derived from unknown proteins present in the foraminiferal organic matrices. The amino acid distribution of these peptides was queried against the uniprot database and the mollusk uniprot database for comparison. The mollusks compose a well-studied phylum that yield a large variety of biomineralization proteins. These results showed that proteins extracted from S. floresiana shells contained sequences enriched with glycine, alanine, and proline, making a set of residues that provided a signature unique to foraminifera. Three of the de novo peptides exhibited sequence similarities to peptides found in proteins such as pre-collagen-P and a group of P-type ATPases including a calcium-transporting ATPase. Surprisingly, the peptide that was most similar to the collagen-like protein was a glycine-rich peptide reported from the test and spine proteome of sea urchin. The molecules, identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry analyses, included acid-soluble N-glycoproteins with its sugar moieties represented by high-mannose-type glycans and carbohydrates. Describing the nature of the proteins, and associated molecules in the skeletal structure of living foraminifera, can elucidate the biomineralization mechanisms of these major carbonate producers in marine

  16. A catchment-scale carbon and greenhouse gas budget of a subarctic landscape

    DEFF Research Database (Denmark)

    Christensen, Torben R.; Johansson, Paul Torbjörn; Olsrud, Maria

    2007-01-01

    This is the first attempt to budget average current annual carbon (C) and associated greenhouse gas (GHG) exchanges and transfers in a subarctic landscape, the Lake Torneträsk catchment in northern Sweden. This is a heterogeneous area consisting of almost 4000km2 of mixed heath, birch and pine fo...... be compared with the carbon emissions of less than 200 people who live permanently in the catchment, although this comparison disregards substantial emissions from the non-Swedish tourism and transportation activities....... in the heaths to significant CO2 uptake in the forests and also large emissions of CH4 from the mires and small lakes. The overall catchment budget, given the size distribution of the individual ecosystem types and a first approximation of run-off as dissolved organic carbon, reveals a landscape currently......This is the first attempt to budget average current annual carbon (C) and associated greenhouse gas (GHG) exchanges and transfers in a subarctic landscape, the Lake Torneträsk catchment in northern Sweden. This is a heterogeneous area consisting of almost 4000km2 of mixed heath, birch and pine...

  17. Regional carbon and CO2 budgets of North Sea tidal estuaries

    Science.gov (United States)

    Volta, C.; Laruelle, G. G.; Regnier, P.

    2016-07-01

    This study presents the first regional application of the generic estuarine reactive-transport model C-GEM (Carbon-Generic Estuary Model) that is here combined with high-resolution databases to produce a carbon and CO2 budget for all tidal estuaries discharging into the North Sea. Steady-state simulations are performed for yearly-averaged conditions to quantify the carbon processing in the six main tidal estuaries Elbe, Ems, Humber, Scheldt, Thames, and Weser, which show contrasted physical and biogeochemical dynamics and contribute the most to the regional filter. The processing rates derived from these simulations are then extrapolated to the riverine carbon loads of all the other North Sea catchments intercepted by smaller tidal estuarine systems. The Rhine-Meuse estuarine system is also included in the carbon budget and overall, we calculate that the export of organic and inorganic carbon from tidal estuaries to the North sea amounts to 44 and 409 Gmol C yr-1, respectively, while 41 Gmol C are lost annually through CO2 outgassing. The carbon is mostly exported from the estuaries in its inorganic form (>90%), a result that reflects the low organic/inorganic carbon ratio of the riverine waters, as well as the very intense decomposition of organic carbon within the estuarine systems. Our calculations also reveal that with a filtering capacity of 15% for total carbon, the contribution of estuaries to the CO2 outgassing is relatively small. Organic carbon dynamics is dominated by heterotrophic degradation, which also represents the most important contribution to the estuarine CO2 evasion. Nitrification only plays a marginal role in the CO2 dynamics, while the contribution of riverine oversaturated waters to the CO2 outgassing is generally significant and strongly varies across systems.

  18. The role of fire in the boreal carbon budget

    Science.gov (United States)

    Harden, J.W.; Trumbore, S.E.; Stocks, B.J.; Hirsch, A.; Gower, S.T.; O'Neill, K. P.; Kasischke, E.S.

    2000-01-01

    To reconcile observations of decomposition rates, carbon inventories, and net primary production (NPP), we estimated long-term averages for C exchange in boreal forests near Thompson, Manitoba. Soil drainage as defined by water table, moss cover, and permafrost dynamics, is the dominant control on direct fire emissions. In upland forests, an average of about 10-30% of annual NPP was likely consumed by fire over the past 6500 years since these landforms and ecosystems were established. This long-term, average fire emission is much larger than has been accounted for in global C cycle models and may forecast an increase in fire activity for this region. While over decadal to century times these boreal forests may be acting as slight net sinks for C from the atmosphere to land, periods of drought and severe fire activity may result in net sources of C from these systems.

  19. Biomineralization of Schlumbergerella floresiana, a significant carbonate-producing benthic foraminifer

    Science.gov (United States)

    Sabbatini, Anna; Bédouet, Laurent; Marie, Arul; Bartolini, Annachiara; Landemarre, Ludovic; Weber, Michele; Ngurah Kade Mahardika, Gusti; Berland, Sophie; Zito, Francesca; Vénec-Peyré, Marie-Thérèse

    2016-04-01

    Most foraminifera that produce a shell are efficient biomineralizers. They contribute to the global carbon cycle, and thus influence ocean-climate regulation. Calcification in foraminifera is likely biologically controlled and is potentially similar to shell formation in metazoan taxa (e.g. mollusks, corals, sea urchins). However, foraminiferal biomineralization processes and the molecules involved are still poorly understood. We analyzed the calcitic shell of the large tropical benthic foraminifer Schlumbergerella floresiana. We found a suite of macromolecules containing many charged and polar amino acids and glycine that are also abundant in biomineralization proteins of other phyla. As neither genomic nor transcriptomic data are available for foraminiferal biomineralization yet, de novo-generated sequences, obtained from organic matrices submitted to MS BLAST database search, led to the characterization of 156 peptides. Very few homologous proteins were matched in the proteomic database, implying that the peptides are derived from unknown proteins present in the foraminiferal organic matrices. The amino acid distribution of these peptides was queried against the UNIPROT database and the mollusk UNIPROT database for comparison. The mollusks compose a well-studied phylum that yield a large variety of biomineralization proteins. These results showed that proteins extracted from S. floresiana shells contained sequences enriched with glycine, alanine, and proline, making a set of residues that provided a signature unique to foraminifera. Three of the de novo peptides exhibited sequence similarities to peptides found in proteins such as pre-collagen-P and a group of P-type ATPases including a calcium-transporting ATPase. Surprisingly, the peptide that was most similar to the collagen-like protein was a glycine-rich peptide reported from the test and spine proteome of sea urchin. The molecules, identified by matrix-assisted laser desorption ionization-time of flight

  20. Impact of short-lived non-CO2 mitigation on carbon budgets for stabilizing global warming

    NARCIS (Netherlands)

    Rogelj, Joeri; Meinshausen, M.; Schaeffer, M.; Knutti, R.; Riahi, Keywan

    2015-01-01

    Limiting global warming to any level requires limiting the total amount of CO2 emissions, or staying within a CO2 budget. Here we assess how emissions from short-lived non-CO2 species like methane, hydrofluorocarbons (HFCs), black-carbon, and sulphates influence these CO2 budgets. Our default case,

  1. Accounting for urban biogenic fluxes in regional carbon budgets.

    Science.gov (United States)

    Hardiman, Brady S; Wang, Jonathan A; Hutyra, Lucy R; Gately, Conor K; Getson, Jackie M; Friedl, Mark A

    2017-08-15

    Many ecosystem models incorrectly treat urban areas as devoid of vegetation and biogenic carbon (C) fluxes. We sought to improve estimates of urban biomass and biogenic C fluxes using existing, nationally available data products. We characterized biogenic influence on urban C cycling throughout Massachusetts, USA using an ecosystem model that integrates improved representation of urban vegetation, growing conditions associated with urban heat island (UHI), and altered urban phenology. Boston's biomass density is 1/4 that of rural forests, however 87% of Massachusetts' urban landscape is vegetated. Model results suggest that, kilogram-for-kilogram, urban vegetation cycles C twice as fast as rural forests. Urban vegetation releases (RE) and absorbs (GEE) the equivalent of 11 and 14%, respectively, of anthropogenic emissions in the most urban portions of the state. While urban vegetation in Massachusetts fully sequesters anthropogenic emissions from smaller cities in the region, Boston's UHI reduces annual C storage by >20% such that vegetation offsets only 2% of anthropogenic emissions. Asynchrony between temporal patterns of biogenic and anthropogenic C fluxes further constrains the emissions mitigation potential of urban vegetation. However, neglecting to account for biogenic C fluxes in cities can impair efforts to accurately monitor, report, verify, and reduce anthropogenic emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. The effect of induced anoxia and reoxygenation on benthic fluxes of organic carbon, phosphate, iron, and manganese.

    Science.gov (United States)

    Skoog, Annelie C; Arias-Esquivel, Victor A

    2009-11-15

    Eutrophication causes seasonally anoxic bottom waters in coastal environments, but we lack information on effects of onset of anoxia and subsequent reoxygenation on benthic fluxes of redox-sensitive minerals and associated organic carbon (OC). As the first study, we determined the effect of inducing anoxia and subsequently restoring oxic conditions in mesocosms with surface sediment and water from a coastal environment. These concentration changes were compared with those in an oxygenated control. We determined water column concentrations of dissolved organic carbon (DOC), particulate organic carbon (POC), iron, manganese, and phosphate. Benthic fluxes of DOC, POC, and iron increased at the onset of anoxia in oxygen-depleted treatments. DOC and iron concentrations increased concomitantly towards maxima, which may have indicated reductive dissolution of FeOOH and release of associated OC. The subsequent concomitant concentration decreases may have been the result of coprecipitation of OC with iron-containing minerals. In contrast, the phosphate-concentration increase occurred several days after the onset of anoxia and the manganese concentration was not affected by the onset of anoxia. Restoring oxic conditions resulted in a decrease in DOC, POC, and phosphate concentrations, which may indicate coprecipitation of OC with phosphate-containing minerals. The high DOC fluxes at the onset of anoxia indicate that redox oscillations may be important in OC degradation. Further, our results indicate a close coupling between OC cycling and dissolution/precipitation of iron-containing minerals in intermittently anoxic sediments.

  3. Ecosystem carbon budgeting and soil carbon sequestration in reclaimed mine soil.

    Science.gov (United States)

    Shrestha, Raj K; Lal, Rattan

    2006-08-01

    Global warming risks from emissions of green house gases (GHGs) by anthropogenic activities, and possible mitigation strategies of terrestrial carbon (C) sequestration have increased the need for the identification of ecosystems with high C sink capacity. Depleted soil organic C (SOC) pools of reclaimed mine soil (RMS) ecosystems can be restored through conversion to an appropriate land use and adoption of recommended management practices (RMPs). The objectives of this paper are to (1) synthesize available information on carbon dioxide (CO2) emissions from coal mining and combustion activities, (2) understand mechanisms of SOC sequestration and its protection, (3) identify factors affecting C sequestration potential in RMSs, (4) review available methods for the estimation of ecosystem C budget (ECB), and (5) identify knowledge gaps to enhance C sink capacity of RMS ecosystems and prioritize research issues. The drastic perturbations of soil by mining activities can accentuate CO2 emission through mineralization, erosion, leaching, changes in soil moisture and temperature regimes, and reduction in biomass returned to the soil. The reclamation of drastically disturbed soils leads to improvement in soil quality and development of soil pedogenic processes accruing the benefit of SOC sequestration and additional income from trading SOC credits. The SOC sequestration potential in RMS depends on amount of biomass production and return to soil, and mechanisms of C protection. The rate of SOC sequestration ranges from 0.1 to 3.1 Mg ha(-1) yr(-1) and 0.7 to 4 Mg ha(-1) yr(-1) in grass and forest RMS ecosystem, respectively. Proper land restoration alone could off-set 16 Tg CO2 in the U.S. annually. However, the factors affecting C sequestration and protection in RMS leading to increase in microbial activity, nutrient availability, soil aggregation, C build up, and soil profile development must be better understood in order to formulate guidelines for development of an

  4. Dust deposition in an oligotrophic marine environment: impact on the carbon budget

    Directory of Open Access Journals (Sweden)

    C. Guieu

    2014-01-01

    Full Text Available By bringing new nutrients and particles to the surface ocean, atmospheric deposition impacts biogeochemical cycles. The extent to which those changes are modifying the carbon balance in oligotrophic environments such as the Mediterranean Sea that receives important Saharan dust fluxes is unknown. DUNE project provides the first attempt to evaluate the changes induced in the carbon budget of an oligotrophic system after simulated Saharan dust wet and dry deposition events. Here we report the results for the 3 distinct artificial dust seeding experiments in large mesocosms that were conducted in the oligotrophic waters of the Mediterranean Sea in summer 2008 and 2010. Simultaneous measurements of the metabolic rates (C fixation, C respiration in the water column have shown that the dust deposition did not change drastically the metabolic balance as the tested waters remained net heterotroph (i.e. net primary production to bacteria respiration ratio < 1 and in some cases the net heterotrophy was even enhanced by the dust deposition. Considering the different terms of the carbon budget, we estimate that it was balanced with a dissolved organic carbon (DOC consumption of at least 10% of the initial stock. This corresponds to a fraction of the DOC stock of the surface mixed layer that consequently will not be exported during the winter mixing. Although heterotrophic bacteria were found to be the key players in the response to dust deposition, net primary production increased about twice in case of simulated wet deposition (that includes anthropogenic nitrogen and a small fraction of particulate organic carbon was still exported. Our estimated carbon budgets are an important step forward in the way we understand dust deposition and associated impacts on the oceanic cycles. They are providing knowledge about the key processes (i.e. bacteria respiration, aggregation that need to be considered for an integration of atmospheric deposition in marine

  5. Centennial evolution of the atmospheric methane budget: what do the carbon isotopes tell us?

    Directory of Open Access Journals (Sweden)

    K. R. Lassey

    2006-06-01

    Full Text Available Little is known about how the methane source inventory and sinks have evolved over recent centuries. New and detailed records of methane mixing ratio and isotopic composition (12CH4, 13CH4 and 14CH4 from analyses of air trapped in polar ice and firn can enhance this knowledge. We use existing bottom-up constructions of the source history, including ''EDGAR''-based constructions, to assemble a model of the evolving global budget for methane and for its carbon isotope composition through the 20th century. By matching such budgets to atmospheric data, we examine the constraints imposed by isotope information on those budget evolutions. Balancing both 12CH4 and 13CH4 budgets requires participation by a highly-fractionating atmospheric sink such as active chlorine (removing at least 10 Tg yr-1, which has been proposed independently. Examining a companion budget evolution for 14CH4 exposes uncertainties in inferring the fossil-methane source from atmospheric 14CH4 data. Specifically, methane evolution during the nuclear era is sensitive to the cycling dynamics of ''bomb 14C'' (originating from atmospheric weapons tests through the biosphere. In addition, since ca 1970, direct production and release of 14CH4 from nuclear-power facilities is influential but poorly quantified. Atmospheric 14CH4 determinations in the nuclear era have the potential to better characterize biospheric carbon cycling and to better quantify the ill-determined nuclear-power source.

  6. Centennial evolution of the atmospheric methane budget: what do the carbon isotopes tell us?

    Directory of Open Access Journals (Sweden)

    K. R. Lassey

    2007-01-01

    Full Text Available Little is known about how the methane source inventory and sinks have evolved over recent centuries. New and detailed records of methane mixing ratio and isotopic composition (12CH4, 13CH4 and 14CH4 from analyses of air trapped in polar ice and firn can enhance this knowledge. We use existing bottom-up constructions of the source history, including "EDGAR"-based constructions, as inputs to a model of the evolving global budget for methane and for its carbon isotope composition through the 20th century. By matching such budgets to atmospheric data, we examine the constraints imposed by isotope information on those budget evolutions. Reconciling both 12CH4 and 13CH4 budgets with EDGAR-based source histories requires a combination of: a greater proportion of emissions from biomass burning and/or of fossil methane than EDGAR constructions suggest; a greater contribution from natural such emissions than is commonly supposed; and/or a significant role for active chlorine or other highly-fractionating tropospheric sink as has been independently proposed. Examining a companion budget evolution for 14CH4 exposes uncertainties in inferring the fossil-methane source from atmospheric 14CH4 data. Specifically, methane evolution during the nuclear era is sensitive to the cycling dynamics of "bomb 14C" (originating from atmospheric weapons tests through the biosphere. In addition, since ca. 1970, direct production and release of 14CH4 from nuclear-power facilities is influential but poorly quantified. Atmospheric 14CH4 determinations in the nuclear era have the potential to better characterize both biospheric carbon cycling, from photosynthesis to methane synthesis, and the nuclear-power source.

  7. Carbon isotopes of benthic foraminifera associated with methane seeps in Four-Way Closure Ridge, offshore southwestern Taiwan

    Science.gov (United States)

    Wang, W. R.; Wei, K. Y.; Mii, H. S.; Lin, Y. S.; Huang, J. J.; Wang, P. L.; Lin, A. T.

    2015-12-01

    Release of large amounts of methane from marine gas hydrate reservoirs has been considered as a possible trigger of climate change, which can be recorded by the variation of carbon isotopes (δ13C) of the benthic foraminifera. In modern analogs, previous studies have suggested that δ13C becomes more negative when influenced by methane seeps. However, values of δ13C of benthic foraminifera might vary with different species and sedimentary settings in different regions. Seismic profiles in offshore southwestern Taiwan show the existence of Bottom Simulating Reflector (BSR) in the region, indicative of gas hydrate reservoirs. Various methane seepages have been found, and they are suspected to be related to the gas hydrates buried underneath. A better understanding of the δ13C signals of benthic foraminifera near the methane seepages can further clarify the origin of the methane and to evaluate it as a proxy of methane release for the geologic past. We have analyzed δ13C of benthic foraminifera Uvigerina proboscidea (150-250 mm) in the topmost 15 cm sediments in five marine cores (OR1-1092-WFWC-1, OR1-1092-WFWC-4, OR1-1092-WFWC-6, OR3-1806-C5-2 and OR3-1806-C10) collected from the Four-Way Closure Ridge in offshore southwestern Taiwan (water depth from 1330 to 1580 m). Our results show that δ13C values of U. proboscidea range from -0.98‰ to -6.21‰ (VPDB) for core OR3-1806-C5-2, which is considered as a seeps-influenced site. On the other hand, δ13C values of U. proboscidea from the background sites range from -0.40‰ to -1.00‰. The difference between the methane seep-affected and the background sites is in the range of 0.00‰ to 5.01‰, comparable to those documented in previous studies in other areas. The significant negative excursion in carbon isotopes in the seep site foraminifera is likely caused by incorporation of light inorganic carbon generated by methanotrophy in the system.

  8. Discerning the cows from the pasture when determining annual NEE and carbon budget

    Science.gov (United States)

    Ammann, Christof; Felber, Raphael; Neftel, Albrecht

    2015-04-01

    The CO2 exchange of ecosystems and the resulting annual net ecosystem exchange (NEE) and total carbon budget (soil carbon sequestration) is commonly investigated using the eddy covariance (EC) technique. For the carbon budget of managed ecosystems also the import and export of organic carbon has to be taken into account. Grazed pasture systems represent a special challenge because their respiration can considerably contribute to the measured CO2 flux, but this contribution depends on the spatial distribution of the cows relative to the footprint and thus is variable in time. This has implications for the gap filling of CO2 flux time series necessary to determine annual NEE. In few existing studies two procedures have been suggested to determine the NEE of grazed pasture: (a) discarding all cases with cows in the footprint and gap-filling the remaining dataset; (b) treating the cow respiration as part of total ecosystem respiration and gap fill the entire flux dataset including cow contributions. Both approaches rely on idealized assumptions and have limitations. In our study we evaluated and compared the two approaches (for the first time to our knowledge) for a grazed pasture in Switzerland. For this purpose, the grazing cows were equipped with GPS sensors to monitor their position relative to the flux footprint. We found that the resulting annual NEE strongly depends on the flux data selection (e.g. u* filtering) and the applied gap filling procedure. Using an optimized procedure, the annual NEE with approach (b) was several times larger than the result of approach (a), but the difference agreed fairly well with independent estimates of cow respiration. Necessary assumptions and requirements of the two approaches for the determination of the pasture carbon budget will be discussed.

  9. Temporal Variability of Carbon and Nutrient Budgets from a Tropical Lagoon in Chiku, Southwestern Taiwan

    Science.gov (United States)

    Hung, J.-J.; Kuo, F.

    2002-05-01

    Biogeochemical processes and budgets of carbon, nitrogen and phosphorus from the semi-enclosed Chiku Lagoon were constructed through periodic observations and modelling. During the investigation, samples were mostly collected bimonthly, and hydrochemical properties, inorganic and organic nutrients (DIN, DON, DIP, DOP, Dsi (dissolved silica)) and organic carbon (DOC, POC) from waters associated with the lagoon were measured. The water exchange time of Chiku Lagoon ranges from 1·0 d (June 1997) to 8·5 d (January 1997) with an annual mean of 5·0 d. The residence time of nutrients varies with water exchange time, and is about 2-5 d longer than the water exchange time. Terrestrial inputs and lagoon distributions of nutrients varied in time and space based on the time scale of sampling. Thus, carbon and nutrient budgets were prepared for each sampling period and then combined to form annual budgets, which differed significantly from those modelled from annual means of various parameters. The annual removal of terrestrial nutrient inputs to the lagoon system is 69·4, 47·0, 27·7 and 42·0%, respectively, for DIN, DON, DIP and DOP. Consequently, the nonconservative flux of dissolved inorganic phosphorus (ΔDIP) from the lagoon is around -0·1 mole m-2 yr-1, that is equivalent to an internal organic carbon sink of 11 mol C m-2 yr-1. This organic carbon budget indicates that the lagoon is an autotrophic system where photosynthesis exceeds respiration (p-r> 0). This carbon sink is one of largest reported from world's lagoons, and its large size may result from the abundant nutrients in the lagoon. However, although the Chiku Lagoon is estimated to remove 4·7 mol C m-2 yr-1 carbonate through oyster calcification, it emits an equivalent amount of CO2 into the system. Despite net nitrogen fixation being observed during some periods, denitrification exceeds nitrogen fixation throughout the period of observation [(nfix-denit)=-1·4 mole N m-2 yr-1].

  10. Can heterotrophic uptake of dissolved organic carbon and zooplankton mitigate carbon budget deficits in annually bleached corals?

    Science.gov (United States)

    Levas, Stephen; Grottoli, Andréa G.; Schoepf, Verena; Aschaffenburg, Matthew; Baumann, Justin; Bauer, James E.; Warner, Mark E.

    2016-06-01

    Annual coral bleaching events due to increasing sea surface temperatures are predicted to occur globally by the mid-century and as early as 2025 in the Caribbean, and severely impact coral reefs. We hypothesize that heterotrophic carbon (C) in the form of zooplankton and dissolved organic carbon (DOC) is a significant source of C to bleached corals. Thus, the ability to utilize multiple pools of fixed carbon and/or increase the amount of fixed carbon acquired from one or more pools of fixed carbon (defined here as heterotrophic plasticity) could underlie coral acclimatization and persistence under future ocean-warming scenarios. Here, three species of Caribbean coral— Porites divaricata, P. astreoides, and Orbicella faveolata—were experimentally bleached for 2.5 weeks in two successive years and allowed to recover in the field. Zooplankton feeding was assessed after single and repeat bleaching, while DOC fluxes and the contribution of DOC to the total C budget were determined after single bleaching, 11 months on the reef, and repeat bleaching. Zooplankton was a large C source for P. astreoides, but only following single bleaching. DOC was a source of C for single-bleached corals and accounted for 11-36 % of daily metabolic demand (CHARDOC), but represented a net loss of C in repeat-bleached corals. In repeat-bleached corals, DOC loss exacerbated the negative C budgets in all three species. Thus, the capacity for heterotrophic plasticity in corals is compromised under annual bleaching, and heterotrophic uptake of DOC and zooplankton does not mitigate C budget deficits in annually bleached corals. Overall, these findings suggest that some Caribbean corals may be more susceptible to repeat bleaching than to single bleaching due to a lack of heterotrophic plasticity, and coral persistence under increasing bleaching frequency may ultimately depend on other factors such as energy reserves and symbiont shuffling.

  11. Soil carbon budget in different-aged Chinese fir plantations in south China

    Institute of Scientific and Technical Information of China (English)

    Shebao Yu; Dan Wang; Wei Dai; Ping Li

    2014-01-01

    Understanding the age effect on soil carbon balance in forest ecosystems is important for other material cycles and forest man-agement. In this research we investigated soil organic carbon density, litter production, litter decomposition rate, soil respiration, and soil mi-crobial properties in a chronosequence of four Chinese fir plantations of 7, 16, 23 and 29 years at Dagangshan mountain range, Jiangxi Province, south China. There was a significant increasing trend in litter production with increasing plantation age. Litter decomposition rate and soil respira-tion, however, declined from the 7-year to the 16-year plantation, and then increased after 16 years. This was largely dependent on soil micro-organisms. Soil carbon output was higher than carbon input before 16 years, and total soil carbon stock declined from 35.98 t·ha-1 in the 7-year plantation to 30.12 t·ha-1 in the 16-year plantation. Greater litter produc-tion could not explain the greater soil carbon stock, suggesting that forest growth impacted this microbial process that controlled rates of soil car-bon balance together with litter and soil respiration. The results highlight the importance of the development stage in assessing soil carbon budget and its significance to future management of Chinese fir plantations.

  12. The annual carbon budget for fen and forest in a wetland at Arctic treeline

    Energy Technology Data Exchange (ETDEWEB)

    Rouse, W. R. [McMaster Univ., School of Geography and Geology, Hamilton, ON (Canada); Bello, R. L.; D' Souza, A. [York Univ., Dept. of Geography, Toronto, ON (Canada); Griffis, T. J. [Minnesota Univ., Dept. of Soil, Water and Climate, St. Paul, MN (United States); LaFleur, P. M. [Trent Univ., Dept. of Geography, Peterborough, ON (Canada)

    2002-09-01

    This study of a wetland system at the Arctic treeline compares two carbon budget estimates, one derived from long-term growth rates of organic soil and the other based on shorter-term flux measurements. Result showed that while there was a small loss of carbon from the ecosystem in the case of tundra fen over a period of fifty-three years, the adjacent open subarctic forest showed large gains in atmospheric carbon dioxide during the same period. These longer-term data were supported by shorter-term flux measurements, which also showed carbon loss by the fen and carbon uptake by the forest. The shorter term data indicate that the carbon loss from the fen during this period was attributable to one particularly dry year. The different rates of carbon exchange appear to be controlled by two primary factors. The first is the enhanced development in the fen of a photosynthesis-inhibiting hummock-hollow landscape, while the second is related to warmer and drier average growing season conditions, which inhibit carbon dioxide uptake in the fen and enhances it in the forest. 24 refs., 4 tabs., 3 figs.

  13. Carbon Budgets for Caribbean Mangrove Forests of Varying Structure and with Phosphorus Enrichment

    Directory of Open Access Journals (Sweden)

    Catherine E. Lovelock

    2015-10-01

    Full Text Available There are few detailed carbon (C budgets of mangrove forests, yet these are important for understanding C sequestration in mangrove forests, how they support the productivity of the coast and their vulnerability to environmental change. Here, we develop C budgets for mangroves on the islands of Twin Cays, Belize. We consider seaward fringing forests and interior scrub forests that have been fertilized with phosphorus (P, which severely limits growth of trees in the scrub forests. We found that respiration of the aboveground biomass accounted for 60%–80% of the fixed C and that respiration of the canopy and aboveground roots were important components of respiration. Soil respiration accounted for only 7%–11% of total gross primary production (GPP while burial of C in soils was ~4% of GPP. Respiration by roots can account for the majority of soil respiration in fringing forests, while microbial processes may account 80% of respiration in scrub forests. Fertilization of scrub forests with P enhanced GPP but the proportion of C buried declined to ~2% of GPP. Net ecosystem production was 17%–27% of GPP similar to that reported for other mangrove forests. Carbon isotope signatures of adjacent seagrass suggest that dissolved C from mangroves is exported into the adjacent ecosystems. Our data indicate that C budgets can vary among mangrove forest types and with nutrient enrichment and that low productivity mangroves provide a disproportionate share of exported C.

  14. Bleaching drives collapse in reef carbonate budgets and reef growth potential on southern Maldives reefs

    Science.gov (United States)

    Perry, C. T.; Morgan, K. M.

    2017-01-01

    Sea-surface temperature (SST) warming events, which are projected to increase in frequency and intensity with climate change, represent major threats to coral reefs. How these events impact reef carbonate budgets, and thus the capacity of reefs to sustain vertical growth under rising sea levels, remains poorly quantified. Here we quantify the magnitude of changes that followed the ENSO-induced SST warming that affected the Indian Ocean region in mid-2016. Resultant coral bleaching caused an average 75% reduction in coral cover (present mean 6.2%). Most critically we report major declines in shallow fore-reef carbonate budgets, these shifting from strongly net positive (mean 5.92 G, where G = kg CaCO3 m-2 yr-1) to strongly net negative (mean -2.96 G). These changes have driven major reductions in reef growth potential, which have declined from an average 4.2 to -0.4 mm yr-1. Thus these shallow fore-reef habitats are now in a phase of net erosion. Based on past bleaching recovery trajectories, and predicted increases in bleaching frequency, we predict a prolonged period of suppressed budget and reef growth states. This will limit reef capacity to track IPCC projections of sea-level rise, thus limiting the natural breakwater capacity of these reefs and threatening reef island stability.

  15. Simulated effects of nitrogen saturation on the global carbon budget using the IBIS model

    Science.gov (United States)

    Lu, Xuehe; Jiang, Hong; Liu, Jinxun; Zhang, Xiuying; Jin, Jiaxin; Zhu, Qiuan; Zhang, Zhen; Peng, Changhui

    2016-12-01

    Over the past 100 years, human activity has greatly changed the rate of atmospheric N (nitrogen) deposition in terrestrial ecosystems, resulting in N saturation in some regions of the world. The contribution of N saturation to the global carbon budget remains uncertain due to the complicated nature of C-N (carbon-nitrogen) interactions and diverse geography. Although N deposition is included in most terrestrial ecosystem models, the effect of N saturation is frequently overlooked. In this study, the IBIS (Integrated BIosphere Simulator) was used to simulate the global-scale effects of N saturation during the period 1961–2009. The results of this model indicate that N saturation reduced global NPP (Net Primary Productivity) and NEP (Net Ecosystem Productivity) by 0.26 and 0.03 Pg C yr‑1, respectively. The negative effects of N saturation on carbon sequestration occurred primarily in temperate forests and grasslands. In response to elevated CO2 levels, global N turnover slowed due to increased biomass growth, resulting in a decline in soil mineral N. These changes in N cycling reduced the impact of N saturation on the global carbon budget. However, elevated N deposition in certain regions may further alter N saturation and C-N coupling.

  16. Simulated effects of nitrogen saturation the global carbon budget using the IBIS model

    Science.gov (United States)

    Lu, Xuehe; Jiang, Hong; Liu, Jinxun; Zhang, Xiuying; Jin, Jiaxin; Zhu, Qiuan; Zhang, Zhen; Peng, Changhui

    2016-01-01

    Over the past 100 years, human activity has greatly changed the rate of atmospheric N (nitrogen) deposition in terrestrial ecosystems, resulting in N saturation in some regions of the world. The contribution of N saturation to the global carbon budget remains uncertain due to the complicated nature of C-N (carbon-nitrogen) interactions and diverse geography. Although N deposition is included in most terrestrial ecosystem models, the effect of N saturation is frequently overlooked. In this study, the IBIS (Integrated BIosphere Simulator) was used to simulate the global-scale effects of N saturation during the period 1961–2009. The results of this model indicate that N saturation reduced global NPP (Net Primary Productivity) and NEP (Net Ecosystem Productivity) by 0.26 and 0.03 Pg C yr−1, respectively. The negative effects of N saturation on carbon sequestration occurred primarily in temperate forests and grasslands. In response to elevated CO2 levels, global N turnover slowed due to increased biomass growth, resulting in a decline in soil mineral N. These changes in N cycling reduced the impact of N saturation on the global carbon budget. However, elevated N deposition in certain regions may further alter N saturation and C-N coupling.

  17. The carbon budget in the northern Adriatic Sea, a winter case study

    Science.gov (United States)

    Catalano, G.; Azzaro, M.; Bastianini, M.; Bellucci, L. G.; Bernardi Aubry, F.; Bianchi, F.; Burca, M.; Cantoni, C.; Caruso, G.; Casotti, R.; Cozzi, S.; Del Negro, P.; Fonda Umani, S.; Giani, M.; Giuliani, S.; Kovacevic, V.; La Ferla, R.; Langone, L.; Luchetta, A.; Monticelli, L. S.; Piacentino, S.; Pugnetti, A.; Ravaioli, M.; Socal, G.; Spagnoli, F.; Ursella, L.

    2014-07-01

    This paper presents a winter carbon budget for the northern Adriatic Sea, obtained through direct measurements during two multidisciplinary cruises and literature data. A box model approach was adopted to integrate estimates of stocks and fluxes of carbon species over the total area. The oligotrophy at the basin scale and the start of primary productivity well before the onset of spring stratification were observed. In winter, the system underwent a complete reset, as the mixing of water masses erased any signal of previous hypoxia or anoxia episodes. The northern Adriatic Sea was phosphorus depleted with respect to C and N availability. This fact confirms the importance of mixing with deep-sea water for P supply to biological processes on the whole. Despite the abundant prokaryotic biomass, the microbial food web was less efficient in organic C production than phytoplankton. In the upper layer, the carbon produced by primary production exceeded the fraction respired by planktonic community smaller than 200 µm. On the contrary, respiration processes prevailed in the water column below the pycnocline. The carbon budget also proved that the northern Adriatic Sea can be an effective sink for atmospheric CO2 throughout the entire winter season.

  18. Carbon budget estimation of a subarctic catchment using a dynamic ecosystem model at high spatial resolution

    Science.gov (United States)

    Tang, J.; Miller, P. A.; Persson, A.; Olefeldt, D.; Pilesjo, P.; Heliasz, M.; Jackowicz-Korczynski, M.; Yang, Z.; Smith, B.; Callaghan, T. V.; Christensen, T. R.

    2015-05-01

    A large amount of organic carbon is stored in high-latitude soils. A substantial proportion of this carbon stock is vulnerable and may decompose rapidly due to temperature increases that are already greater than the global average. It is therefore crucial to quantify and understand carbon exchange between the atmosphere and subarctic/arctic ecosystems. In this paper, we combine an Arctic-enabled version of the process-based dynamic ecosystem model, LPJ-GUESS (version LPJG-WHyMe-TFM) with comprehensive observations of terrestrial and aquatic carbon fluxes to simulate long-term carbon exchange in a subarctic catchment at 50 m resolution. Integrating the observed carbon fluxes from aquatic systems with the modeled terrestrial carbon fluxes across the whole catchment, we estimate that the area is a carbon sink at present and will become an even stronger carbon sink by 2080, which is mainly a result of a projected densification of birch forest and its encroachment into tundra heath. However, the magnitudes of the modeled sinks are very dependent on future atmospheric CO2 concentrations. Furthermore, comparisons of global warming potentials between two simulations with and without CO2 increase since 1960 reveal that the increased methane emission from the peatland could double the warming effects of the whole catchment by 2080 in the absence of CO2 fertilization of the vegetation. This is the first process-based model study of the temporal evolution of a catchment-level carbon budget at high spatial resolution, including both terrestrial and aquatic carbon. Though this study also highlights some limitations in modeling subarctic ecosystem responses to climate change, such as aquatic system flux dynamics, nutrient limitation, herbivory and other disturbances, and peatland expansion, our study provides one process-based approach to resolve the complexity of carbon cycling in subarctic ecosystems while simultaneously pointing out the key model developments for capturing

  19. Carbon Budget Proposal: An Institutional Framework for an Equitable and Sustainable World Climate Regime%Carbon Budget Proposal: An Institutional Framework for an Equitable and Sustainable World Climate Regime

    Institute of Scientific and Technical Information of China (English)

    Pan Jiahua; Chen Ying

    2011-01-01

    Consensus on reducing greenhouse gas emissions has been reached at the technical and political level. However, as the issue involves economic costs and the right to develop, the international institutional framework for addressing greenhouse gas emissions has consistently failed to balance the demands of impartiality and sustainability. However, a sustainable carbon budget proposal is undoubtedly achievable if the global carbon budget (the total amount of carbon permitted by climate security) is made an absolute constraint. If a preliminary distribution was made among the world's population on a per capita basis, the total limited global carbon budget could not only meet basic needs but also ensure the proposal's equitable. Taking into account historical emission levels and future needs, we should carry out carbon budget transfer payments and devise a corresponding funding mechanism to ensure efficient allocation under the proposal. Unlike the phase-by-phase progress and provisional goals of the Kyoto Protocol, the carbon budget proposal outlined above is a comprehensive and holistic package. Due to the politicization of the climate change issue, however, many technical issues can only be worked out through international political and diplomatic negotiations.

  20. Stable carbon isotope gradients in benthic foraminifera as proxy for organic carbon fluxes in the Mediterranean Sea

    Science.gov (United States)

    Theodor, Marc; Schmiedl, Gerhard; Jorissen, Frans; Mackensen, Andreas

    2016-11-01

    We have determined stable carbon isotope ratios of epifaunal and shallow infaunal benthic foraminifera in the Mediterranean Sea to relate the inferred gradient of pore water δ13CDIC to varying trophic conditions. This is a prerequisite for developing this difference into a potential transfer function for organic matter flux rates. The data set is based on samples retrieved from a well-defined bathymetric range (400-1500 m water depth) of sub-basins in the western, central, and eastern Mediterranean Sea. Regional contrasts in organic matter fluxes and associated δ13CDIC of pore water are recorded by the δ13C difference (Δδ13CUmed-Epi) between the shallow infaunal Uvigerina mediterranea and epifaunal species (Planulina ariminensis, Cibicidoides pachydermus, Cibicides lobatulus). Within epifaunal taxa, the highest δ13C values are recorded for P. ariminensis, providing the best indicator for bottom water δ13CDIC. In contrast, C. pachydermus reveals minor pore water effects at the more eutrophic sites. Because of ontogenetic trends in the δ13C signal of U. mediterranea of up to 1.04 ‰, only tests larger than 600 µm were used for the development of the transfer function. The recorded differences in the δ13C values of U. mediterranea and epifaunal taxa (Δδ13CUmed-Epi) range from -0.46 to -2.13 ‰, with generally higher offsets at more eutrophic sites. The measured δ13C differences are related to site-specific differences in microhabitat, depth of the principal sedimentary redox boundary, and TOC content of the ambient sediment. The Δδ13CUmed-Epi values reveal a consistent relation to Corg fluxes estimated from satellite-derived surface water primary production in open-marine settings of the Alboran Sea, Mallorca Channel, Strait of Sicily, and southern Aegean Sea. In contrast, Δδ13CUmed-Epi values in areas affected by intense resuspension and riverine organic matter sources of the northern to central Aegean Sea and the canyon systems of the Gulf of Lion

  1. Carbon and sulfur budget of the silicate Earth explained by accretion of differentiated planetary embryos

    Science.gov (United States)

    Li, Yuan; Dasgupta, Rajdeep; Tsuno, Kyusei; Monteleone, Brian; Shimizu, Nobumichi

    2016-10-01

    The abundances of volatile elements in the Earth's mantle have been attributed to the delivery of volatile-rich material after the main phase of accretion. However, no known meteorites could deliver the volatile elements, such as carbon, nitrogen, hydrogen and sulfur, at the relative abundances observed for the silicate Earth. Alternatively, Earth could have acquired its volatile inventory during accretion and differentiation, but the fate of volatile elements during core formation is known only for a limited set of conditions. Here we present constraints from laboratory experiments on the partitioning of carbon and sulfur between metallic cores and silicate mantles under conditions relevant for rocky planetary bodies. We find that carbon remains more siderophile than sulfur over a range of oxygen fugacities; however, our experiments suggest that in reduced or sulfur-rich bodies, carbon is expelled from the segregating core. Combined with previous constraints, we propose that the ratio of carbon to sulfur in the silicate Earth could have been established by differentiation of a planetary embryo that was then accreted to the proto-Earth. We suggest that the accretion of a Mercury-like (reduced) or a sulfur-rich (oxidized) differentiated body--in which carbon has been preferentially partitioned into the mantle--may explain the Earth's carbon and sulfur budgets.

  2. Synthesis on the carbon budget and cycling in a Danish, temperate deciduous forest

    DEFF Research Database (Denmark)

    Wu, Jian; Larsen, Klaus Steenberg; van der Linden, Leon

    2013-01-01

    , tree growth, litter production and leaching of dissolved inorganic and organic carbon were independently estimated and used to calculate other unmeasured ecosystem carbon budget (ECB) components, based on mass balance equations. This provided a complete assessment of the carbon storage and allocation...... was considered unchanged over the period of observation, given the high degree of uncertainty associated with the small loss detected (33±85gCm−2 yr−1). The ECB component data were generally consistent, except for one of the derived fluxes, the aboveground autotrophic respiration, which appeared to be higher...... than expected. The potential causes for this, i.e. underestimation of soil respiration and/or overestimation of Re are discussed. The plausibility analyses reported here, using multiple ECB data sets together with simple mass conservation equations and the evaluation of data consistency on the basis...

  3. Global Tree Cover and Biomass Carbon on Agricultural Land: The contribution of agroforestry to global and national carbon budgets

    Science.gov (United States)

    Zomer, Robert J.; Neufeldt, Henry; Xu, Jianchu; Ahrends, Antje; Bossio, Deborah; Trabucco, Antonio; van Noordwijk, Meine; Wang, Mingcheng

    2016-07-01

    Agroforestry systems and tree cover on agricultural land make an important contribution to climate change mitigation, but are not systematically accounted for in either global carbon budgets or national carbon accounting. This paper assesses the role of trees on agricultural land and their significance for carbon sequestration at a global level, along with recent change trends. Remote sensing data show that in 2010, 43% of all agricultural land globally had at least 10% tree cover and that this has increased by 2% over the previous ten years. Combining geographically and bioclimatically stratified Intergovernmental Panel on Climate Change (IPCC) Tier 1 default estimates of carbon storage with this tree cover analysis, we estimated 45.3 PgC on agricultural land globally, with trees contributing >75%. Between 2000 and 2010 tree cover increased by 3.7%, resulting in an increase of >2 PgC (or 4.6%) of biomass carbon. On average, globally, biomass carbon increased from 20.4 to 21.4 tC ha‑1. Regional and country-level variation in stocks and trends were mapped and tabulated globally, and for all countries. Brazil, Indonesia, China and India had the largest increases in biomass carbon stored on agricultural land, while Argentina, Myanmar, and Sierra Leone had the largest decreases.

  4. Effect of ocean acidification on the benthic foraminifera Ammonia sp. is caused by a decrease in carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    J. Bijma

    2013-01-01

    Full Text Available About 30% of the anthropogenically released CO2 is taken up by the oceans, which causes surface ocean pH to decrease and is commonly referred to as Ocean Acidification (OA. Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50% of biogenic calcium carbonate in the open oceans. We have compiled the state of the art of OA effects on foraminifera, because the majority of OA research on this group was published within the last 3 yr. Disparate responses of this important group of marine calcifiers to OA were reported, highlighting the importance of a process based understanding of OA effects on foraminifera. The benthic foraminifer Ammonia sp. was cultured using two carbonate chemistry manipulation approaches: While pH and carbonate ions where varied in one, pH was kept constant in the other while carbonate ion concentration varied. This allows the identification of teh parameter of the parameter of the carbonate system causing observed effects. This parameter identification is the first step towards a process based understanding. We argue that [CO32−] is the parameter affecting foraminiferal size normalized weights (SNW and growth rates and based on the presented data we can confirm the strong potential of foraminiferal SNW as a [CO32−] proxy.

  5. Implications of land use change on the national terrestrial carbon budget of Georgia

    Directory of Open Access Journals (Sweden)

    Olofsson Pontus

    2010-09-01

    Full Text Available Abstract Background Globally, the loss of forests now contributes almost 20% of carbon dioxide emissions to the atmosphere. There is an immediate need to reduce the current rates of forest loss, and the associated release of carbon dioxide, but for many areas of the world these rates are largely unknown. The Soviet Union contained a substantial part of the world's forests and the fate of those forests and their effect on carbon dynamics remain unknown for many areas of the former Eastern Bloc. For Georgia, the political and economic transitions following independence in 1991 have been dramatic. In this paper we quantify rates of land use changes and their effect on the terrestrial carbon budget for Georgia. A carbon book-keeping model traces changes in carbon stocks using historical and current rates of land use change. Landsat satellite images acquired circa 1990 and 2000 were analyzed to detect changes in forest cover since 1990. Results The remote sensing analysis showed that a modest forest loss occurred, with approximately 0.8% of the forest cover having disappeared after 1990. Nevertheless, growth of Georgian forests still contribute a current national sink of about 0.3 Tg of carbon per year, which corresponds to 31% of the country anthropogenic carbon emissions. Conclusions We assume that the observed forest loss is mainly a result of illegal logging, but we have not found any evidence of large-scale clear-cutting. Instead local harvesting of timber for household use is likely to be the underlying driver of the observed logging. The Georgian forests are a currently a carbon sink and will remain as such until about 2040 if the current rate of deforestation persists. Forest protection efforts, combined with economic growth, are essential for reducing the rate of deforestation and protecting the carbon sink provided by Georgian forests.

  6. Effects of Land Use Change for Crops on Water and Carbon Budgets in the Midwest USA

    Directory of Open Access Journals (Sweden)

    Jian Sun

    2017-02-01

    Full Text Available Increasing demand for food and bioenergy has altered the global landscape dramatically in recent years. Land use and land cover change affects the environmental system in many ways through biophysical and biogeochemical mechanisms. In this study, we evaluate the impacts of land use and land cover change driven by recent crop expansion and conversion on the water budget, carbon exchange, and carbon storage in the Midwest USA. A dynamic global vegetation model was used to simulate and examine the impacts of landscape change in a historical case based on crop distribution data from the United States Department of Agriculture National Agricultural Statistics Services. The simulation results indicate that recent crop expansion not only decreased soil carbon sequestration (60 Tg less of soil organic carbon and net carbon flux into ecosystems (3.7 Tg·year−1 less of net biome productivity, but also lessened water consumption through evapotranspiration (1.04 × 1010 m3·year−1 less over 12 states in the Midwest. More water yield at the land surface does not necessarily make more water available for vegetation. Crop residue removal might also exacerbate the soil carbon loss.

  7. Carbon budget estimation of a subarctic catchment using a dynamic ecosystem model at high spatial resolution

    Directory of Open Access Journals (Sweden)

    J. Tang

    2015-01-01

    Eriophorum, Sphagnum and then tundra heath during the observation periods. The catchment-level carbon fluxes from aquatic systems are dominated by CO2 emissions from streams. Integrated across the whole catchment, we estimate that the area is a carbon sink at present, and will become an even stronger carbon sink by 2080, which is mainly a result of a projected densification of birch forest and its encroachment into tundra heath. However, the magnitudes of the modelled sinks are very dependent on future atmospheric CO2 concentrations. Furthermore, comparisons of global warming potentials between two simulations with and without CO2 increase since 1960 reveal that the increased methane emission from the peatland could double the warming effects of the whole catchment by 2080 in the absence of CO2 fertilization of the vegetation. This is the first process-based model study of the temporal evolution of a catchment-level carbon budget at high spatial resolution, integrating comprehensive and diverse fluxes including both terrestrial and aquatic carbon. Though this study also highlights some limitations in modelling subarctic ecosystem responses to climate change including aquatic system flux dynamics, nutrient limitation, herbivory and other disturbances and peatland expansion, our application provides a mechanism to resolve the complexity of carbon cycling in subarctic ecosystems while simultaneously pointing out the key model developments for capturing complex subarctic processes.

  8. Glomospirella cantabrica n. sp., and other benthic foraminifera from Lower Cretaceous Urgonian-type carbonates of Cantabria, Spain: Biostratigraphic implications

    Energy Technology Data Exchange (ETDEWEB)

    Schlagintweit, F.; Rosales, I.; Najarro, M.

    2016-07-01

    A new benthic foraminifer is described as Glomospirella cantabrica n. sp. from several sections of the upper Aptian Reocín Formation and one occurrence from the lowermost Albian Las Peñosas Formation of Cantabria (northern Spain). It represents a rather large-sized Glomospirella, with up to eight planispiral whorls, observed in lagoonal wackestones and packstones. The upper Aptian (upper Gargasian–Clansayesian) age is indicated by the co-occurrence with other benthic foraminifera, i.e. orbitolinids. Further biostratigraphic data of the Aptian-p.p. Albian shallow-water carbonates of the North Cantabrian Basin is provided. The rareness of dasycladalean green algae in these deposits is also highlighted. The resulting stratigraphic and biostratigraphic scheme is integrated in a framework of depositional sequences of the North Cantabrian Basin and compared with the sequential schemes of other areas of the Basque-Cantabrian Basin and the Iberian Chain. Similitudes suggest that these depositional sequences are related to global sea-level changes. (Author)

  9. Significance of Halimeda bioherms to the global carbonate budget based on a geological sediment budget for the Northern Great Barrier Reef, Australia

    Science.gov (United States)

    Rees, S. A.; Opdyke, B. N.; Wilson, P. A.; Henstock, T. J.

    2007-03-01

    Since the correlation between carbon dioxide (CO2) levels and global temperatures was established in the ice core records, quantifying the components of the global carbon cycle has become a priority with a view to constraining models of the climate system. The marine carbonate budget is still not adequately constrained and the quantitative significance of the calcareous green alga Halimeda still remains particularly poorly understood. Previously, it has been suggested that Halimeda bioherms on the shelf of the Great Barrier Reef may contain a volume of carbonate equal to or greater than that contained within the shelf edge coral reefs. This study uses published datasets to test this hypothesis in the Northern Great Barrier Reef (NGBR) province. It is estimated that Halimeda bioherms on the outer shelf of the NGBR contain at least as much (and up to four times more) CaCO3 sediment as the adjacent ribbon reef facies. Globally, if these findings are even only partially applicable, the contribution of shallow water carbonate sediments to the global carbon budget based on coral reefs alone is currently substantially underestimated.

  10. Effects of resuspension on benthic fluxes of oxygen, nutrients, dissolved inorganic carbon, iron and manganese in the Gulf of Finland, Baltic Sea

    NARCIS (Netherlands)

    Almroth, E.; Tengberg, A.; Andersson, J.H.; Pakhomova, S.; Hall, P.O.J.

    2009-01-01

    The effect of resuspension on benthic fluxes of oxygen (O2), ammonium (NH4+), nitrate (NO3-), phosphate (PO43-), silicate (Si(OH)4), dissolved inorganic carbon (DIC), total dissolved iron (Fe) and total dissolved manganese (Mn) was studied at three different stations in the Gulf of Finland (GoF),

  11. Determination of food sources for benthic invertebrates in a salt marsh (Aiguillon Bay, France) by carbon and nitrogen stable isotopes: importance of locally produced sources

    NARCIS (Netherlands)

    Riera, P.; Stal, L.J.; Nieuwenhuize, J.; Richard, P.; Blanchard, G.F.; Gentil, F.

    1999-01-01

    delta(13)C and delta(15)N were measured in benthic invertebrates and food sources collected in the salt marsh of the Aiguillon Bay, France. The results showed that, although Spartina anglica was dominant, this marine phanerogame did not contribute significantly to the carbon and nitrogen requirement

  12. Organic carbon burial rates in mangrove sediments: Strengthening the global budget

    Science.gov (United States)

    Breithaupt, Joshua L.; Smoak, Joseph M.; Smith, Thomas J., III; Sanders, Christian J.; Hoare, Armando

    2012-09-01

    Mangrove wetlands exist in the transition zone between terrestrial and marine environments and as such were historically overlooked in discussions of terrestrial and marine carbon cycling. In recent decades, mangroves have increasingly been credited with producing and burying large quantities of organic carbon (OC). The amount of available data regarding OC burial in mangrove soils has more than doubled since the last primary literature review (2003). This includes data from some of the largest, most developed mangrove forests in the world, providing an opportunity to strengthen the global estimate. First-time representation is now included for mangroves in Brazil, Colombia, Malaysia, Indonesia, China, Japan, Vietnam, and Thailand, along with additional data from Mexico and the United States. Our objective is to recalculate the centennial-scale burial rate of OC at both the local and global scales. Quantification of this rate enables better understanding of the current carbon sink capacity of mangroves as well as helps to quantify and/or validate the other aspects of the mangrove carbon budget such as import, export, and remineralization. Statistical analysis of the data supports use of the geometric mean as the most reliable central tendency measurement. Our estimate is that mangrove systems bury 163 (+40; -31) g OC m-2 yr-1 (95% C.I.). Globally, the 95% confidence interval for the annual burial rate is 26.1 (+6.3; -5.1) Tg OC. This equates to a burial fraction that is 42% larger than that of the most recent mangrove carbon budget (2008), and represents 10-15% of estimated annual mangrove production. This global rate supports previous conclusions that, on a centennial time scale, 8-15% of all OC burial in marine settings occurs in mangrove systems.

  13. The experimental studies on the carbon and nitrogen budgets of Pseudeuphausia sinica

    Institute of Scientific and Technical Information of China (English)

    Guo Donghui; Li Shaojing; Chen Feng; Wang Guizhong; Chen Gang

    2003-01-01

    The carbon and nitrogen budgets were estimated on the adult females, juveniles and postfurcilia larvae of Pseudeuphausia sinica fed on newly hatching nauplii of Artemia salina in the laboratory. It was found that the ingestion rate was linearly related to the food concentration, suggesting high feeding potential. The linear correlation could be established between the respirating rate (carbon consumption rate) and carbon ingestion rate, as well as carbon assimilation rate. The regression coefficients (i.e.specific dynamic action coefficients) were in the range from 9% to 16% (ingested C) or 10% to 17% (assimilated C) respectively, with lower in the post-furcilia larvae. There also existed a linear correlation equation between estimated total nitrogen excretion rate and the rates of nitrogen ingestion and assimilation separately, except for the juveniles. The defecation rates increased with the increase of the ingestion rate; as a result, assimilation efficiency was not related to the ingestion rate, ranging from 0.84 to 0.95. The results inducated that the nitrogen content in food particles was a key factor limiting the growth of P. sinica. The critical ingestion rate was 10 μgN@mg-1body dry weight per day. Assimilated N was lost mostly by excretion, following allocated to somatic growth. The nitrogen loss by moult only accounted for a minor part. As for carbon budget, respiration and somatic growth also accounted for most of assimilation, but varied with ingestion rates. Moult loss was minor. Estimated reproductive growth (C&N) in the adult females accounted for somewhat higher percent of assimilation than the moult growth. The net growth efficiency (K2) increased with the increase of the ingestion rates, but decreased slightly for juvenile and post-furcilia larvae after the rates up to a certain value.

  14. Organic carbon burial rates in mangrove sediments: strengthening the global budget

    Science.gov (United States)

    Breithaupt, J.; Smoak, Joseph M.; Smith, Thomas J.; Sanders, Christian J.; Hoare, Armando

    2012-01-01

    Mangrove wetlands exist in the transition zone between terrestrial and marine environments and as such were historically overlooked in discussions of terrestrial and marine carbon cycling. In recent decades, mangroves have increasingly been credited with producing and burying large quantities of organic carbon (OC). The amount of available data regarding OC burial in mangrove soils has more than doubled since the last primary literature review (2003). This includes data from some of the largest, most developed mangrove forests in the world, providing an opportunity to strengthen the global estimate. First-time representation is now included for mangroves in Brazil, Colombia, Malaysia, Indonesia, China, Japan, Vietnam, and Thailand, along with additional data from Mexico and the United States. Our objective is to recalculate the centennial-scale burial rate of OC at both the local and global scales. Quantification of this rate enables better understanding of the current carbon sink capacity of mangroves as well as helps to quantify and/or validate the other aspects of the mangrove carbon budget such as import, export, and remineralization. Statistical analysis of the data supports use of the geometric mean as the most reliable central tendency measurement. Our estimate is that mangrove systems bury 163 (+40; -31) g OC m-2 yr-1 (95% C.I.). Globally, the 95% confidence interval for the annual burial rate is 26.1 (+6.3; -5.1) Tg OC. This equates to a burial fraction that is 42% larger than that of the most recent mangrove carbon budget (2008), and represents 10–15% of estimated annual mangrove production. This global rate supports previous conclusions that, on a centennial time scale, 8–15% of all OC burial in marine settings occurs in mangrove systems.

  15. Estimating the carbon budget and maximizing future carbon uptake for a temperate forest region in the U.S.

    Directory of Open Access Journals (Sweden)

    Peckham Scott D

    2012-06-01

    Full Text Available Abstract Background Forests of the Midwest U.S. provide numerous ecosystem services. Two of these, carbon sequestration and wood production, are often portrayed as conflicting. Currently, carbon management and biofuel policies are being developed to reduce atmospheric CO2 and national dependence on foreign oil, and increase carbon storage in ecosystems. However, the biological and industrial forest carbon cycles are rarely studied in a whole-system structure. The forest system carbon balance is the difference between the biological (net ecosystem production and industrial (net emissions from forest industry forest carbon cycles, but to date this critical whole system analysis is lacking. This study presents a model of the forest system, uses it to compute the carbon balance, and outlines a methodology to maximize future carbon uptake in a managed forest region. Results We used a coupled forest ecosystem process and forest products life cycle inventory model for a regional temperate forest in the Midwestern U.S., and found the net system carbon balance for this 615,000 ha forest was positive (2.29 t C ha-1 yr-1. The industrial carbon budget was typically less than 10% of the biological system annually, and averaged averaged 0.082 t C ha-1 yr-1. Net C uptake over the next 100-years increased by 22% or 0.33 t C ha-1 yr-1 relative to the current harvest rate in the study region under the optized harvest regime. Conclusions The forest’s biological ecosystem current and future carbon uptake capacity is largely determined by forest harvest practices that occurred over a century ago, but we show an optimized harvesting strategy would increase future carbon sequestration, or wood production, by 20-30%, reduce long transportation chain emissions, and maintain many desirable stand structural attributes that are correlated to biodiversity. Our results for this forest region suggest that increasing harvest over the next 100

  16. Biogeochemical processes in sediments of the Manfredonia Gulf (Southern Adriatic Sea: early diagenesis of carbon and nutrient and benthic exchange

    Directory of Open Access Journals (Sweden)

    P. Giordano

    2004-10-01

    Full Text Available In order to understand the mechanisms responsible of the recycle of carbon and nutrients at the sediment-water interface and to understand the role of sediments in nutrients mass balance in coastal water, cores were collected (pore waters and solid phases and benthic fluxes (oxygen, dissolved nutrients, dissolved iron and managanese, alkalinity and TCO2 were measured in two stations in the Gulf of Manfredonia (Southern Adriatic Sea. Stations were chosen to include a site, in the offshore part of the gulf, under the influence of western Adriatic current and another site, in the inner part of the gulf, under influence of gyres occurring inside the gulf. Both stations were placed in areas characterized by high sedimentation rate. Fluxes at sediment water interface show higher values in S2 site during the summer. Bio-irrigation seems to be the main transport mechanism characterizing both sites, with more evident effects during summer in S1 site.

  17. Carbon budget over 12 years in a production crop under temperate climate

    Science.gov (United States)

    Buysse, Pauline; Bodson, Bernard; Debacq, Alain; De Ligne, Anne; Heinesch, Bernard; Manise, Tanguy; Moureaux, Christine; Aubinet, Marc

    2017-04-01

    Carbon dioxide (CO2) exchanges between crops and the atmosphere are influenced by both climatic and crop management drivers. The investigated crop, situated at the Lonzée Terrestrial Observatory (LTO, candidate ICOS site) in Belgium and managed for more than 70 years using conventional farming practices, was monitored over three complete sugar beet (or maize)/winter wheat/potato/winter wheat rotation cycles from 2004 to 2016. Continuous eddy-covariance measurements and regular biomass samplings were performed in order to obtain the daily and seasonal Net Ecosystem Exchange (NEE), Gross Primary Productivity, Total Ecosystem Respiration, Net Primary Productivity, and Net Biome Production (NBP). Meteorological data and crop management practices were also recorded. The main objectives were to analyze the CO2 flux responses to climatic drivers and to establish the C budget of the cropland. Crop type significantly influenced the measured CO2 fluxes. In addition to crop season duration, which had an obvious impact on cumulated NEE values for each crop type, the CO2 flux response to photosynthetic photon flux density, vapor pressure deficit and temperature differed between crop types, while no significant response to soil water content was observed in any of them. Besides, a significant positive relationship between crop residue amount and ecosystem respiration was observed. Over the 12 years, NEE was negative (-4.34 ± 0.21 kg C m-2) but NBP was positive (1.05 ± 0.30 kg C m-2), i.e. as soon as all lateral carbon fluxes - dominated by carbon exportation - are included in the budget, the site behaves as a carbon source. Intercrops were seen to play a major role in the carbon budget, being mostly due to the long time period it represented (59 % of the 12 year time period). An in-depth analysis of intercrop periods and, more specifically, growing cover crops (mustard in the case of our study), is developed in a companion poster (ref. abstract EGU2017-12216, session SSS9

  18. An eddy covariance derived annual carbon budget for an arctic terrestrial ecosystem (Disko, Greenland)

    Science.gov (United States)

    McConnell, Alistair; Lund, Magnus; Friborg, Thomas

    2016-04-01

    Ecosystems with underlying permafrost cover nearly 25% of the ice-free land area in the northern hemisphere and store almost half of the global soil carbon. Future climate changes are predicted to have the most pronounced effect in northern latitudes. These Arctic ecosystems are therefore subject to dramatic changes following thawing of permafrost, glacial retreat, and coastal erosion. The most dramatic effect of permafrost thawing is the accelerated decomposition and potential mobilization of organic matter stored in the permafrost. This will impact global climate through the mobilization of carbon and nitrogen accompanied by release of greenhouses gases, including carbon dioxide. This study presents the initial findings and first full annual carbon (CO2) budget, derived from eddy covariance measurements, for an Arctic landscape in West Greenland. The study site, a terrestrial Arctic maritime climate, is located at Østerlien, near Qeqertarsuaq, on the southern coast of Disko Island in central West Greenland (69° 15' N, 53° 34' W) within the transition zone from continuous to discontinuous permafrost. The mean annual air temperature is -5 C and the annual precipitation as rain is 150-200 mm. Arctic ecosystem feedback mechanisms and processes interact on micro, local and regional scales. This is further complicated by several potential feedback mechanisms likely to occur in permafrost-affected ecosystems, involving the interactions of microorganisms, vegetation and soil. The eddy covariance method allows us to interrogate the processes and drivers of land-atmosphere carbon exchange at extremely high temporary frequency (10 Hz), providing landscape-scale measurements of CO2, H2O and heat fluxes for the site, which are processed to derive daily, monthly and now, annual carbon fluxes. We discuss the scientific methodology, challenges, and analysis, as well as the practical and logistic challenges of working in the Arctic, and present an annual carbon budget

  19. Current and Future Carbon Budgets of Tropical Rain Forest: A Cross Scale Analysis. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Oberbauer, S. F.

    2004-01-16

    The goal of this project was to make a first assessment of the major carbon stocks and fluxes and their climatic determinants in a lowland neotropical rain forest, the La Selva Biological Station, Costa Rica. Our research design was based on the concurrent use of several of the best available approaches, so that data could be cross-validated. A major focus of our effort was to combine meteorological studies of whole-forest carbon exchange (eddy flux), with parallel independent measurements of key components of the forest carbon budget. The eddy flux system operated from February 1998 to February 2001. To obtain field data that could be scaled up to the landscape level, we monitored carbon stocks, net primary productivity components including tree growth and mortality, litterfall, woody debris production, root biomass, and soil respiration in a series of replicated plots stratified across the major environmental gradients of the forest. A second major focus of this project was on the stocks and changes of carbon in the soil. We used isotope studies and intensive monitoring to investigate soil organic stocks and the climate-driven variation of soil respiration down the soil profile, in a set of six 4m deep soil shafts stratified across the landscape. We measured short term tree growth, climate responses of sap flow, and phenology in a suite of ten canopy trees to develop individual models of tree growth to daytime weather variables.

  20. Using Carbon flux network data to investigate the impact of new European greening rules on carbon budgets - a case study.

    Science.gov (United States)

    Schmidt, Marius; Graf, Alexander; Carsten, Montzka; Vereecken, Harry

    2017-04-01

    In 2015 the European Commission introduced new greening payments as part of their common agricultural practices to address environmental and sustainability issues. The payment is worth about 30% of the total subsidies for European farmers. Sowing nitrogen fixing catch/cover crops in the off season (generally in fall and winter) is one way to achieve the prerequisite for the greening payments. Therefore it is expected that the proportion of catch/cover crops will increase from 2015 onwards at the expense of bare soil fields. In particular, with regard to more frequently occurring mild weather conditions during fall and winter, we assume that the extensive shift to catch/cover crops will have a significant impact on the carbon cycle of agricultural areas. In this study we aim to evaluate this change in agricultural practice on local and regional CO2 fluxes and carbon budgets of the intensively used northern Rur catchment in Germany. In a preliminary study, we observed the daily courses of net CO2 flux and soil respiration of three different catch/cover crops: greening mix, oil radish, and white mustard (Sinapis alba), by means of a net flux chamber and a soil respiration chamber and compared them against Eddy covariance flux data from fields cultivated with (i) winter barley (Hordeum vulgare), and (ii) without vegetation. In the main study, we compare multi-year measurements of carbon fluxes from a regional network of Eddy Covariance sites, partly included in larger networks like Fluxnet, European Fluxes Database Cluster or ICOS. We especially used site data where comparisons of catch crop seasons and conventional seasons between different sites or years were possible. To allow an assessment of the change in carbon fluxes and budgets on regional scale, a land use comparison based on satellite images for the years 2014 to 2016 was applied. With these results, a first regional evaluation of the impact of the new greening policies on carbon fluxes and budgets for the

  1. Sensitivity of regional forest carbon budgets to continuous and stochastic climate change pressures

    Science.gov (United States)

    Sulman, B. N.; Desai, A. R.; Scheller, R. M.

    2010-12-01

    Climate change is expected to impact forest-atmosphere carbon budgets through three processes: 1. Increased disturbance rates, including fires, mortality due to pest outbreaks, and severe storms 2. Changes in patterns of inter-annual variability, related to increased incidence of severe droughts and defoliating insect outbreaks 3. Continuous changes in forest productivity and respiration, related to increases in mean temperature, growing season length, and CO2 fertilization While the importance of these climate change effects in future regional carbon budgets has been established, quantitative characterization of the relative sensitivity of forested landscapes to these different types of pressures is needed. We present a model- and- data-based approach to understanding the sensitivity of forested landscapes to climate change pressures. Eddy-covariance and biometric measurements from forests in the northern United States were used to constrain two forest landscape models. The first, LandNEP, uses a prescribed functional form for the evolution of net ecosystem productivity (NEP) over the age of a forested grid cell, which is reset following a disturbance event. This model was used for investigating the basic statistical properties of a simple landscape’s responses to climate change pressures. The second model, LANDIS-II, includes different tree species and models forest biomass accumulation and succession, allowing us to investigate the effects of more complex forest processes such as species change and carbon pool accumulation on landscape responses to climate change effects. We tested the sensitivity of forested landscapes to these three types of climate change pressures by applying ensemble perturbations of random disturbance rates, distribution functions of inter-annual variability, and maximum potential carbon uptake rates, in the two models. We find that landscape-scale net carbon exchange responds linearly to continuous changes in potential carbon uptake and

  2. Revision of The Global Carbon Budget Due To Changing Air-sea Oxygen Fluxes

    Science.gov (United States)

    Plattner, G.-K.; Joos, F.; Stocker, T. F.

    A quantitative understanding of the carbon cycle is important to optimize global warming mitigation strategies. The classic method, applying an ocean model to esti- mate the partitioning of anthropogenic carbon between the global terrestrial and ocean carbon sinks has been complemented by various data-based methods. Here, we inves- tigate how global warming and volcanic eruptions affect sea-to-air oxygen (O2) fluxes and, in turn, the carbon budgets for the last two decades deduced from the observed trends in atmospheric carbon dioxide (CO2) and O2; the latter estimated from mea- surements of the ratio of oxygen to nitrogen (O2/N2) in air. By forcing a physical- biogeochemical climate model of intermediate complexity with reconstructed natu- ral and anthropogenic radiative forcing, we find a significant oceanic O2 outgassing mainly due to changes in ocean circulation and biological cycling (78%) and, to a lesser extent, due to surface warming (22%). Simulated sea-to-air O2 fluxes and ocean heat uptake rates are tightly correlated on multi-annual to multi-decadal time scales. A change in oceanic heat uptake of 1022 J corresponds to an increase in atmospheric O2/N2 of 1.56 per meg when correlating simulated heat fluxes and associated O2/N2 changes over the period 1900 to 2000. We combine this relation with data of ocean heat uptake and atmospheric O2/N2 and CO2. Thereby we attempt to account for inter- nal climate variability not readily reproduced by models for individual decades. The inferred terrestrial carbon sink for the 1990s is reduced by a factor of two compared with the most recent estimate by the Intergovernmental Panel on Climate Change (IPCC). This brings also into agreement calculated oceanic CO2 uptake rates with estimates from global carbon cycle models, which indicate a higher oceanic CO2 up- take during the 1990s than the 1980s.

  3. Effect of ocean acidification on the benthic foraminifera Ammonia sp. is caused by a decrease in carbonate ion concentration

    Directory of Open Access Journals (Sweden)

    N. Keul

    2013-10-01

    Full Text Available About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA. Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic calcium carbonate in the open oceans. We have compiled the state of the art literature on OA effects on foraminifera, because the majority of OA research on this group was published within the last three years. Disparate responses of this important group of marine calcifiers to OA were reported, highlighting the importance of a process-based understanding of OA effects on foraminifera. We cultured the benthic foraminifer Ammonia sp. under a range of carbonate chemistry manipulation treatments to identify the parameter of the carbonate system causing the observed effects. This parameter identification is the first step towards a process-based understanding. We argue that [CO32−] is the parameter affecting foraminiferal size-normalized weights (SNWs and growth rates. Based on the presented data, we can confirm the strong potential of Ammonia sp. foraminiferal SNW as a [CO32−] proxy.

  4. The importance of phytoplankton production for carbon budgets in a semiarid floodplain wetland

    Directory of Open Access Journals (Sweden)

    Álvarez-Cobelas, Miguel

    2011-12-01

    Full Text Available Phytoplankton production (PP in wetlands is not measured as often as that of macrophytes. A three year-study during a period of sustained high flooding was undertaken in a central Spanish floodplain wetland (Las Tablas de Daimiel National Park to determine net PP, its spatial heterogeneity and controlling factors, and compare it with primary production in macrophyte communities. This enabled us to estimate carbon budgets for each community. All PP variables showed high spatial and temporal variability among sites, resulting in low coherence even when flooding connected all sites. Net PP corresponded to 25- 36% of submerged plant production and 3-10% of helophyte production. Net PP was controlled by different size fractions of phytoplankton biomass at different wetland sites. Neither nutrients nor zooplankton affected net PP or productivity. A high spatiotemporal variability of PP in wetlands occurs arising from complex processes that affect the underwater light field. Carbon budgets of phytoplankton often exceeded those of submerged macrophytes and attained between 4 and 37% of helophyte budgets. Although usually considered to be marginal, our study shows that PP in the open water of wetlands should be taken into account for determining accurate wetland carbon budgets, mostly in periods of high flooding, which often result in changing the carbon budget of primary producers.

    La producción de fitoplancton (PF en los humedales no se mide tan a menudo como la de los macrófitos. En este estudio se lleva a cabo un trabajo de tres años durante un periodo de gran inun dación en un humedal de llanura de inundación (Parque Nacional de Las Tablas de Daimiel a fin de determinar la producción neta del fitoplancton, su heterogeneidad espacial y los factores que la controlan. También comparamos la PF con la producción primaria de las comunidades de macrófitos, lo cual nos permite estimar las cantidades de carbono que fija cada comunidad vegetal

  5. Canopy carbon budget of Siebold's beech (Fagus crenata) sapling under free air ozone exposure.

    Science.gov (United States)

    Watanabe, Makoto; Hoshika, Yasutomo; Inada, Naoki; Koike, Takayoshi

    2014-01-01

    To determine the effects of ozone (O3) on the canopy carbon budget, we investigated photosynthesis and respiration of leaves of Siebold's beech saplings under free air O3 exposure (60 nmol mol(-1), during daytime) in relation to the within-canopy light gradient; we then calculated the canopy-level photosynthetic carbon gain (PCG) and respiratory carbon loss (RCL) using a canopy photosynthesis model. Susceptibilities of photosynthesis and respiration to O3 were greater in leaves of upper canopy than in the lower canopy. The canopy net carbon gain (NCG) was reduced by O3 by 12.4% during one growing season. The increased RCL was the main factor for the O3-induced reduction in NCG in late summer, while contributions of the reduced PCG and the increased RCL to the NCG were almost the same in autumn. These results indicate contributions of changes in PCG and RCL under O3 to NCG were different between seasons.

  6. Patterns and controls of inter-annual variability in the terrestrial carbon budget

    Directory of Open Access Journals (Sweden)

    B. Marcolla

    2017-08-01

    Full Text Available The terrestrial carbon fluxes show the largest variability among the components of the global carbon cycle and drive most of the temporal variations in the growth rate of atmospheric CO2. Understanding the environmental controls and trends of the terrestrial carbon budget is therefore essential to predict the future trajectories of the CO2 airborne fraction and atmospheric concentrations. In the present work, patterns and controls of the inter-annual variability (IAV of carbon net ecosystem exchange (NEE have been analysed using three different data streams: ecosystem-level observations from the FLUXNET database (La Thuile and 2015 releases, the MPI-MTE (model tree ensemble bottom–up product resulting from the global upscaling of site-level fluxes, and the Jena CarboScope Inversion, a top–down estimate of surface fluxes obtained from observed CO2 concentrations and an atmospheric transport model. Consistencies and discrepancies in the temporal and spatial patterns and in the climatic and physiological controls of IAV were investigated between the three data sources. Results show that the global average of IAV at FLUXNET sites, quantified as the standard deviation of annual NEE, peaks in arid ecosystems and amounts to  ∼  120 gC m−2 y−1, almost 6 times more than the values calculated from the two global products (15 and 20 gC m−2 y−1 for MPI-MTE and the Jena Inversion, respectively. Most of the temporal variability observed in the last three decades of the MPI-MTE and Jena Inversion products is due to yearly anomalies, whereas the temporal trends explain only about 15 and 20 % of the variability, respectively. Both at the site level and on a global scale, the IAV of NEE is driven by the gross primary productivity and in particular by the cumulative carbon flux during the months when land acts as a sink. Altogether these results offer a broad view on the magnitude, spatial patterns and environmental drivers of IAV

  7. An Empirical Riverine Carbon Budget for New Zealand: National scale estimate of organic and inorganic carbon.

    Science.gov (United States)

    Scott, D. T.; Baisden, W. T.; Davies-Colley, R.; Trustrum, N.

    2002-12-01

    New Zealand rivers contribute a large amount of sediment to the ocean, partially attributable to tectonic uplift combined with softer rocks under inappropriate land-use and high-frequency rain events. Preliminary calculations suggest that in NZ between 3-11 Mt carbon is transported annually through erosion, compared with about 8.5 Mt per yr released from fossil fuel burning. Therefore, if a large proportion of this erosional carbon is oxidized before sequestration in sedimentary basins, soil erosion may represent a major greenhouse contribution. Our current study aims to refine a national estimate of both particulate and dissolved organic carbon leaving New Zealand through rivers. We are also attempting to understand both the biochemical processing of organic matter in transit to the ocean, as well as the resulting evasional flux of CO2 to the atmosphere. Initial estimates of these fluxes based on measurements collected over a 12-month period from 50 rivers, as well as from a number of flood snapshots around the country, will be presented. Using surrogates such as spectrophotometric absorbance for DOC developed using this year's dataset, these measurements will be used to quantify the annual riverine flux of particulate and organic carbon from a 12-year record. Carbon fluxes from individual catchments will also be compared to landscape properties (soil parent material, slope, climate, and land-use patterns). The relationship between the solute flux from and landscape properties within a catchment is crucial to extending the estimates of carbon flux to ungauged catchments to estimate total carbon flux in river drainage from the NZ landmass.

  8. Forest carbon budgets in Southeast Asia following harvesting and land cover change

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Terrestrial ecosystems play an important role in the global carbon (C)cycle. Tropical forests in Southeast Asia are constantly changing as a result of harvesting and conversion to other land cover. As a result of these changes, research on C budgets of forest ecosystems has intensified in the region over thelast few years. This paper reviews and synthesizes the available information. Natural forests in SE Asia typically contain a high C density (up to 500 Mg/ha). Logging activities are responsible for at least 50% decline in forest C density.Complete deforestation (conversion from forest to grassland or annual crops) results in C density of less than 40 Mg/ha. Conversion to tree plantations and other woody perennial crops also reduces C density to less than 50% of the originalC forest stocks. While much information has been generated recently, there are still large gaps of information on C budgets of tropical forests and its conversion to other land uses in SE Asia. There is therefore a need to intensify research in this area.

  9. Multi-Sensor Model-Data Assimilation for Improved Modeling of Savanna Carbon and Water Budgets

    Science.gov (United States)

    Barrett, D. J.; Renzullo, L. J.; Guerschman, J.; Hill, M. J.

    2007-12-01

    Model-data assimilation methods are increasingly being used to improve model predictions of carbon pools and fluxes, soil profile moisture contents, and evapotranspiration at catchment to regional scales. In this talk, I will discuss the development of model-data assimilation methods for application to parameter and state estimation problems in the context of savanna carbon and water cycles. A particular focus of this talk will be on the integration of in situ datasets and multiple types of satellite observations with radiative transfer, surface energy balance, and carbon budget models. An example will be drawn from existing work demonstrating regional estimation of soil profile moisture content based on multiple satellite sensors. The data assimilation scheme comprised a forward model, observation operators, multiple observation datasets and an optimization scheme. The forward model propagates model state variables in time based on climate forcing, initial conditions and model parameters and includes processes governing evapotranspiration, water budget and carbon cycle processes. The observation operators calculate modeled land surface temperature and microwave brightness temperatures based on the state variables of profile soil moisture and soil surface layer soil moisture at less than 2.5 cm depth. Satellite observations used in the assimilation scheme are surface brightness temperatures from AMSR-E (passive microwave at 6.9GHz at horizontal polarization) and from AVHRR (thermal channels 4 & 5 from NOAA-18), and land surface reflectances from MODIS Terra (channels 1 and 2 at 250m resolution). These three satellite sensors overpass at approximately the same time of day and provide independent observations of the land surface at different wavelengths. The observed brightness temperatures are used as constraints on the coupled energy balance/microwave radiative transfer model, and a canopy optical model was inverted to retrieve leaf area indices from observed

  10. Evidence for benthic-pelagic food web coupling and carbon export from California margin bamboo coral archives

    Directory of Open Access Journals (Sweden)

    T. M. Hill

    2014-02-01

    Full Text Available Deep-sea bamboo corals (order Gorgonacea, family Isididae are known to record changes in water mass chemistry over decades to centuries. These corals are composed of a two-part skeleton of calcite internodes segmented by gorgonin organic nodes. We examine the spatial variability of bamboo coral organic node 13C/12C and 15N/14N from thirteen bamboo coral specimens sampled along the California margin (37–32° N; 792 to 2136 m depth. Radiocarbon analyses of the organic nodes show the presence of the anthropogenic bomb spike, indicating the corals utilize a surface-derived food source (pre-bomb D14C values of ∼ −100‰, post-bomb values to 82‰. Carbon and nitrogen isotope data from the organic nodes (13C = −15.9‰ to −19.2‰ 15N = 13.8‰ to 19.4‰ suggest selective feeding on surface-derived organic matter or zooplankton. A strong relationship between coral 15N and habitat depth indicate a potential archive of changing carbon export, with decreased 15N values reflecting reduced microbial degradation (increased carbon flux at shallower depths. Using four multi-centennial length coral records, we interpret long-term 15N stability in the California Current. Organic node 13C values record differences in carbon isotope fractionation dictated by nearshore vs. offshore primary production. These findings imply strong coupling between primary production, pelagic food webs, and deep-sea benthic communities.

  11. Benthic solute exchange and carbon mineralization in two shallow subtidal sandy sediments: Effect of advective pore-water exchange

    DEFF Research Database (Denmark)

    Cook, Perran L. M.; Wenzhofer, Frank; Glud, Ronnie N.;

    2007-01-01

    of O-2 distribution across ripples, and also deep subsurface O-2 pools, being observed. Mineralization pathways were predominantly aerobic when benthic mineralization rates were low and advective pore-water flow high as a result of well-developed sediment topography. By contrast, mineralization...... proceeded predominantly through sulfate reduction when benthic mineralization rates were high and advective pore-water flow low as a result of poorly developed topography. Previous studies of benthic mineralization in shallow sandy sediments have generally ignored these dynamics and, hence, have overlooked......We conducted four field campaigns to evaluate benthic O-2 consumption and the effect of advective pore-water flow in nearshore permeable sediments in the North Sea and Baltic Sea. Advective pore-water transport had a marked effect on the benthic exchange of O-2 and TCO2 in benthic chamber...

  12. Carbon budgets for an irrigated intensively grazed dairy pasture and an unirrigated winter-grazed pasture

    Science.gov (United States)

    Hunt, John E.; Laubach, Johannes; Barthel, Matti; Fraser, Anitra; Phillips, Rebecca L.

    2016-05-01

    Intensification of pastoral agriculture is occurring rapidly across New Zealand, including increasing use of irrigation and fertiliser application in some regions. While this enables greater gross primary production (GPP) and livestock grazing intensity, the consequences for the net ecosystem carbon budget (NECB) of the pastures are poorly known. Here, we determined the NECB over one year for an irrigated, fertilised and rotationally grazed dairy pasture and a neighbouring unirrigated, unfertilised, winter-grazed pasture. Primary terms in the NECB calculation were: net ecosystem production (NEP), biomass carbon removed by grazing cows and carbon (C) input from their excreta. Annual NEP was measured using the eddy-covariance method. Carbon removal was estimated with plate-meter measurements calibrated against biomass collections, pre- and post-grazing. Excreta deposition was calculated from animal feed intake. The intensively managed pasture gained C (NECB = 103 ± 42 g C m-2 yr-1) but would have been subject to a non-significant C loss if cattle excreta had not been returned to the pasture. The unirrigated pasture was C-neutral (NECB = -13 ± 23 g C m-2 yr-1). While annual GPP of the former was almost twice that of the latter (2679 vs. 1372 g C m-2 yr-1), ecosystem respiration differed by only 68 % between the two pastures (2271 vs. 1352 g C m-2 yr-1). The ratio of GPP to the total annual water input of the irrigated pasture was 37 % greater than that of the unirrigated pasture, i.e. the former used the water input more efficiently than the latter to produce biomass. The NECB results agree qualitatively with those from many other eddy-covariance studies of grazed grasslands, but they seem to be at odds with long-term carbon-stock studies of other New Zealand pastures.

  13. Top-Down Assessment of the Asian Carbon Budget Since the Mid 1990s

    Science.gov (United States)

    Thompson, R.; Canadell, J.; Patra, P. K.; Chevallier, F.; Maksyutov, S. S.; Law, R. M.; Ziehn, T.; van der Laan-Luijkx, I. T.; Peters, W.; Ganshin, A.; Zhuravlev, R.; Maki, T.; Nakamura, T.; Shirai, T.; Ishizawa, M.; Saeki, T.; Poulter, B.; Ciais, P.

    2015-12-01

    Atmospheric carbon dioxide (CO2) is the principle driver of anthropogenic climate change. Asia is an important region for the global carbon budget, with four of the world's ten largest national emitters of CO2, but it is also a region with considerable uncertainty in both anthropogenic emissions and land biosphere fluxes of CO2. Furthermore, Asia has undergone rapid economic growth over the past two decades, which has been associated with large increases in fossil fuel emissions, 190% for India and 240% for China between 1990 and 2010. We have used an ensemble of seven atmospheric CO2 inversions and three standard fossil fuel and cement fluxes, based on the inventories of CDIAC, EDGAR and IEA, to determine the land biosphere fluxes for East, South and Southeast Asia, and to ascertain the robustness and overall uncertainty of the results. We find that the East Asian land biosphere was on average a carbon sink of -0.35 ± 0.37 PgC y-1 (median and MAD), or equivalently 17 ± 18% of East Asia's fossil fuel and cement emissions, over 1996 - 2012. Between 1996 - 2001 and 2008 - 2012, we find an increase in the sink of 0.74 ± 0.28 PgC y-1, however the magnitude of this is contingent on the assumed increase in fossil fuel emissions. For South Asia, we find that on average the land biosphere was close to carbon neutral, -0.01 ± 0.20 PgC y-1 over 1996 - 2012 and that there was no significant trend. For Southeast Asia, we find no evidence for a trend in the land biosphere flux over 1996 - 2012 and we cannot determine any difference from carbon neutrality (as assumed a priori by most inversions) with a flux of 0.06 ± 0.29 PgC y-1, throughout this period despite extensive tropical deforestation.

  14. Revisiting ocean carbon sequestration by direct injection: a global carbon budget perspective

    Science.gov (United States)

    Reith, Fabian; Keller, David P.; Oschlies, Andreas

    2016-11-01

    In this study we look beyond the previously studied effects of oceanic CO2 injections on atmospheric and oceanic reservoirs and also account for carbon cycle and climate feedbacks between the atmosphere and the terrestrial biosphere. Considering these additional feedbacks is important since backfluxes from the terrestrial biosphere to the atmosphere in response to reducing atmospheric CO2 can further offset the targeted reduction. To quantify these dynamics we use an Earth system model of intermediate complexity to simulate direct injection of CO2 into the deep ocean as a means of emissions mitigation during a high CO2 emission scenario. In three sets of experiments with different injection depths, we simulate a 100-year injection period of a total of 70 GtC and follow global carbon cycle dynamics over another 900 years. In additional parameter perturbation runs, we varied the default terrestrial photosynthesis CO2 fertilization parameterization by ±50 % in order to test the sensitivity of this uncertain carbon cycle feedback to the targeted atmospheric carbon reduction through direct CO2 injections. Simulated seawater chemistry changes and marine carbon storage effectiveness are similar to previous studies. As expected, by the end of the injection period avoided emissions fall short of the targeted 70 GtC by 16-30 % as a result of carbon cycle feedbacks and backfluxes in both land and ocean reservoirs. The target emissions reduction in the parameter perturbation simulations is about 0.2 and 2 % more at the end of the injection period and about 9 % less to 1 % more at the end of the simulations when compared to the unperturbed injection runs. An unexpected feature is the effect of the model's internal variability of deep-water formation in the Southern Ocean, which, in some model runs, causes additional oceanic carbon uptake after injection termination relative to a control run without injection and therefore with slightly different atmospheric CO2 and

  15. Carbon cycling in benthic diatom mats: Novel applications of LC/IRMS

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.

    2016-01-01

    Life on our planet is based on carbon and this life-sustaining element is essential in order to live, grow and reproduce. The cycling of carbon from the atmosphere, land and ocean into organisms, and back again needs to be in balance. If not, serious consequences, such as global climate disruption,

  16. Modelling developmental changes in the carbon and nitrogen budgets of larval brachyuran crabs

    Science.gov (United States)

    Anger, K.

    1990-03-01

    The uptake and partitioning of nutritional carbon (C) and nitrogen (N) were studied during the complete larval development of a brachyuran crab, Hyas araneus, reared under constant conditions in the laboratory. Biochemical and physiological data were published in a foregoing paper, and complete budgets of C and N were now constructed from these data. Regression equations describing rates of feeding ( F), growth ( G), respiration ( R), and ammonia excretion ( U) as functions of time during individual larval moult cycles were inserted in a simulation model, in order to analyse time-dependent (i.e. developmental) patterns of variation in these parameters as well as in bioenergetic efficiencies. Absolute daily feeding rates ( F; per individual) as well as carbon and nitrogen-specific rates ( F/C, F/N) are in general maximum in early, and minimum in late stages of individual larval moult cycles (postmoult and premoult, respectively). Early crab zoeae may ingest equivalents of up to ca 40% body C and 30% body N per day, respectively, whereas megalopa larvae usually eat less than 10%. Also growth rates ( G; G/C, G/N) reveal decreasing tendencies both during individual moult cycles and, on the average, in subsequent instars. Conversion of C and N data to lipid and protein, respectively, suggests that in all larval instars there is initially an increase in the lipid: protein ratio. Protein, however, remains clearly the predominant biochemical constituent in larval biomass. The absolute and specific values of respiration ( R; R/C) and excretion ( U; U/N) vary only little during the course of individual moult cycles. Thus, their significance in relation to G increases within the C and N budgets, and net growth efficiency ( K 2) decreases concurrently. Also gross growth and assimilation efficiency ( K 2; A/F) are, in general, maximum in early stages of the moult cycle (postmoult). Biochemical data suggest that lipid utilization efficiency is particularly high in early moult

  17. Soil organic carbon redistribution by water erosion--the role of CO2 emissions for the carbon budget.

    Science.gov (United States)

    Wang, Xiang; Cammeraat, Erik L H; Romeijn, Paul; Kalbitz, Karsten

    2014-01-01

    A better process understanding of how water erosion influences the redistribution of soil organic carbon (SOC) is sorely needed to unravel the role of soil erosion for the carbon (C) budget from local to global scales. The main objective of this study was to determine SOC redistribution and the complete C budget of a loess soil affected by water erosion. We measured fluxes of SOC, dissolved organic C (DOC) and CO2 in a pseudo-replicated rainfall-simulation experiment. We characterized different C fractions in soils and redistributed sediments using density fractionation and determined C enrichment ratios (CER) in the transported sediments. Erosion, transport and subsequent deposition resulted in significantly higher CER of the sediments exported ranging between 1.3 and 4.0. In the exported sediments, C contents (mg per g soil) of particulate organic C (POC, C not bound to soil minerals) and mineral-associated organic C (MOC) were both significantly higher than those of non-eroded soils indicating that water erosion resulted in losses of C-enriched material both in forms of POC and MOC. The averaged SOC fluxes as particles (4.7 g C m(-2) yr(-1)) were 18 times larger than DOC fluxes. Cumulative emission of soil CO2 slightly decreased at the erosion zone while increased by 56% and 27% at the transport and depositional zone, respectively, in comparison to non-eroded soil. Overall, CO2 emission is the predominant form of C loss contributing to about 90.5% of total erosion-induced C losses in our 4-month experiment, which were equal to 18 g C m(-2). Nevertheless, only 1.5% of the total redistributed C was mineralized to CO2 indicating a large stabilization after deposition. Our study also underlines the importance of C losses by particles and as DOC for understanding the effects of water erosion on the C balance at the interface of terrestrial and aquatic ecosystems.

  18. Carbonate Production by Benthic Communities on Shallow Coralgal Reefs of Abrolhos Bank, Brazil.

    Directory of Open Access Journals (Sweden)

    Vanessa Moura Dos Reis

    Full Text Available The abundance of reef builders, non-builders and the calcium carbonate produced by communities established in Calcification Accretion Units (CAUs were determined in three Abrolhos Bank shallow reefs during the period from 2012 to 2014. In addition, the seawater temperature, the irradiance, and the amount and composition of the sediments were determined. The inner and outer reef arcs were compared. CAUs located on the inner reef shelf were under the influence of terrigenous sediments. On the outer reefs, the sediments were composed primarily of marine biogenic carbonates. The mean carbonate production in shallow reefs of Abrolhos was 579 ± 98 g m-2 y-1. The builder community was dominated by crustose coralline algae, while the non-builder community was dominated by turf. A marine heat wave was detected during the summer of 2013-2014, and the number of consecutive days with a temperature above or below the summer mean was positively correlated with the turf cover increase. The mean carbonate production of the shallow reefs of Abrolhos Bank was greater than the estimated carbonate production measured for artificial structures on several other shallow reefs of the world. The calcimass was higher than the non-calcareous mass, suggesting that the Abrolhos reefs are still in a positive carbonate production balance. Given that marine heat waves produce an increase of turf cover on the shallow reefs of the Abrolhos, a decrease in the cover represented by reef builders and shifting carbonate production are expected in the near future.

  19. Carbonate Production by Benthic Communities on Shallow Coralgal Reefs of Abrolhos Bank, Brazil

    Science.gov (United States)

    dos Reis, Vanessa Moura; Karez, Cláudia Santiago; Mariath, Rodrigo; de Moraes, Fernando Coreixas; de Carvalho, Rodrigo Tomazetto; Brasileiro, Poliana Silva; Bahia, Ricardo da Gama; Lotufo, Tito Monteiro da Cruz; Ramalho, Laís Vieira; de Moura, Rodrigo Leão; Francini-Filho, Ronaldo Bastos; Pereira-Filho, Guilherme Henrique; Thompson, Fabiano Lopes; Bastos, Alex Cardoso; Salgado, Leonardo Tavares; Amado-Filho, Gilberto Menezes

    2016-01-01

    The abundance of reef builders, non-builders and the calcium carbonate produced by communities established in Calcification Accretion Units (CAUs) were determined in three Abrolhos Bank shallow reefs during the period from 2012 to 2014. In addition, the seawater temperature, the irradiance, and the amount and composition of the sediments were determined. The inner and outer reef arcs were compared. CAUs located on the inner reef shelf were under the influence of terrigenous sediments. On the outer reefs, the sediments were composed primarily of marine biogenic carbonates. The mean carbonate production in shallow reefs of Abrolhos was 579 ± 98 g m-2 y-1. The builder community was dominated by crustose coralline algae, while the non-builder community was dominated by turf. A marine heat wave was detected during the summer of 2013–2014, and the number of consecutive days with a temperature above or below the summer mean was positively correlated with the turf cover increase. The mean carbonate production of the shallow reefs of Abrolhos Bank was greater than the estimated carbonate production measured for artificial structures on several other shallow reefs of the world. The calcimass was higher than the non-calcareous mass, suggesting that the Abrolhos reefs are still in a positive carbonate production balance. Given that marine heat waves produce an increase of turf cover on the shallow reefs of the Abrolhos, a decrease in the cover represented by reef builders and shifting carbonate production are expected in the near future. PMID:27119151

  20. Carbonate Production by Benthic Communities on Shallow Coralgal Reefs of Abrolhos Bank, Brazil.

    Science.gov (United States)

    Reis, Vanessa Moura Dos; Karez, Cláudia Santiago; Mariath, Rodrigo; de Moraes, Fernando Coreixas; de Carvalho, Rodrigo Tomazetto; Brasileiro, Poliana Silva; Bahia, Ricardo da Gama; Lotufo, Tito Monteiro da Cruz; Ramalho, Laís Vieira; de Moura, Rodrigo Leão; Francini-Filho, Ronaldo Bastos; Pereira-Filho, Guilherme Henrique; Thompson, Fabiano Lopes; Bastos, Alex Cardoso; Salgado, Leonardo Tavares; Amado-Filho, Gilberto Menezes

    2016-01-01

    The abundance of reef builders, non-builders and the calcium carbonate produced by communities established in Calcification Accretion Units (CAUs) were determined in three Abrolhos Bank shallow reefs during the period from 2012 to 2014. In addition, the seawater temperature, the irradiance, and the amount and composition of the sediments were determined. The inner and outer reef arcs were compared. CAUs located on the inner reef shelf were under the influence of terrigenous sediments. On the outer reefs, the sediments were composed primarily of marine biogenic carbonates. The mean carbonate production in shallow reefs of Abrolhos was 579 ± 98 g m-2 y-1. The builder community was dominated by crustose coralline algae, while the non-builder community was dominated by turf. A marine heat wave was detected during the summer of 2013-2014, and the number of consecutive days with a temperature above or below the summer mean was positively correlated with the turf cover increase. The mean carbonate production of the shallow reefs of Abrolhos Bank was greater than the estimated carbonate production measured for artificial structures on several other shallow reefs of the world. The calcimass was higher than the non-calcareous mass, suggesting that the Abrolhos reefs are still in a positive carbonate production balance. Given that marine heat waves produce an increase of turf cover on the shallow reefs of the Abrolhos, a decrease in the cover represented by reef builders and shifting carbonate production are expected in the near future.

  1. Foraminiferal assemblages and organic carbon relationship in benthic marine ecosystem of Western Indian Continental Shelf

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Nigam, R.

    Foraminiferal assemblages in the sediment and their relation to organic carbon have been studied in selected nearshore areas on the west coast, namely, Gulf of Kutch, Bombay-Daman sector, Vengurla-Dabhol sector, Cola Bay and Karwar. Study reveals...

  2. Carbon dioxide budgets in cave air and carbon in speleothems; insights from a shallow cave in Ireland

    Science.gov (United States)

    McDermott, Frank; Phillips, Dominika

    2017-04-01

    The conventional view that hydrological inputs (e.g. drip-water degassing) comprise the dominant source of cave air CO2 has been challenged by recent studies that emphasise the importance of direct advection of gaseous CO2from above and beneath cave voids (e.g. 'soil air' and 'ground air'). A better understanding of CO2 gas budgets in caves is important, not only for the correct interpretation of δ13C values and 14C activity data in speleothems, but also for an understanding of the wider role of karst in the global carbon cycle as a source or sink of atmospheric CO2. This study presents new results from a combined air-temperature and CO2 monitoring programme at a small multi-chamber cave in SE Ireland (Ballynamintra cave, Co. Waterford), building on an earlier study at this cave (Baldini et al., 2006). Episodic, low-amplitude but temporally coherent diurnal-scale cave air temperature fluctuations detected almost simultaneously by a series of temperature loggers within the cave were used to detect air mass advection. The sequence and pattern of temperature fluctuations at different locations within the cave enabled the identification of discrete air-inflow and air-outflow events. These diurnal-scale events occur episodically throughout the year in the winter/ spring and summer/autumn temperature ventilation regimes of the cave. Importantly, changes in cave air pCO2 values recorded by an infra-red logger located in the inner chamber a few metres from the back of the cave occur contemporaneously with the air-mass displacement events, and are consistent with direct advection of CO2-rich soil air via fractures in the subjacent cave roof and walls. In the winter regime, episodic diurnal-scale air outflow events draw CO2-rich air over the logger, resulting in short-lived pulses of air, typically containing c. 0.7% CO2 (by volume), several times the ambient cave air CO2 values at this site. Similar events occur during the summer/autumn thermal regime, but these reach

  3. Carbon budget of Nyungwe Tropical Montane Rain Forest in Central Africa

    Science.gov (United States)

    Nyirambangutse, B.; Zibera, E.; Uwizeye, F. K.; Hansson, L.; Nsabimana, D.; Pleijel, H.; Uddling, J.; Wallin, G.

    2015-12-01

    tree growth (stem, and fine roots), litter fall and soil respiration. Results of the carbon budget defined through the net primary productivity (NPP), autotrophic respiration (Ra) and gross primary productivity (GPP) will be presented, comparing primary and secondary forest communities.

  4. Assessment of benthic flux of dissolved organic carbon in wetland and estuarine sediments using the eddy-correlation technique

    Science.gov (United States)

    Swett, M. P.; Amirbahman, A.; Boss, E.

    2009-12-01

    Wetland and estuarine sediments release significant amounts of dissolved organic carbon (DOC) due to high levels of microbial activity, particularly sulfate reduction. Changes in climate and hydrologic conditions have a potential to alter DOC release from these systems as well. This is a concern, as high levels of DOC can lead to mobilization of toxic metals and organics in natural waters. In addition, source waters high in DOC produce undesirable disinfection byproducts in water treatment. Various in situ methods, such as peepers and sediment core centrifugation, exist to quantify vertical benthic fluxes of DOC and other dissolved species from the sediment-water interface (SWI). These techniques, however, are intrusive and involve disturbance of the sediment environment. Eddy-correlation allows for real-time, non-intrusive, in situ flux measurement of important analytes, such as O2 and DOC. An Acoustic Doppler Velocimeter (ADV) is used to obtain three-dimensional fluid velocity measurements. The eddy-correlation technique employs the mathematical separation of fluid velocity into mean velocity and fluctuating velocity components, with the latter representing turbulent eddy velocity. DOC concentrations are measured using a colored dissolved organic matter (CDOM) fluorometer, and instantaneous vertical flux is determined from the correlated data. This study assesses DOC flux at three project sites: a beaver pond in the Lower Penobscot Watershed, Maine; a mudflat in Penobscot River, Maine; and a mudflat in Great Bay, New Hampshire. Eddy flux values are compared with results obtained using peepers and centrifugation, as well as vertical profiling.

  5. Graphite coated with manganese oxide/multiwall carbon nanotubes composites as anodes in marine benthic microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yubin, E-mail: ffyybb@ouc.edu.cn; Yu, Jian; Zhang, Yelong; Meng, Yao

    2014-10-30

    Highlights: • MnO{sub 2}/MWCNTs composites anode exhibits faster reaction kinetics. • The surfaces of MnO{sub 2}/MWCNTs composites anode exhibits better wettability. • A BMFC using the modified anode have excellent power output. - Abstract: Improving anode performance is of great significance to scale up benthic microbial fuel cells (BMFCs) for its marine application to drive oceanography instruments. In this study, manganese oxide (MnO{sub 2})/multiwall carbon nanotubes (MWCNTs) composites are prepared to be as novel anodes in the BMFCs via a direct redox reaction between permanganate ions (MnO{sub 4}{sup −}) and MWCNTs. The results indicate that the MnO{sub 2}/MWCNTs anode has a better wettability, greater kinetic activity and higher power density than that of the plain graphite (PG) anode. It is noted that the MnO{sub 2} (50% weight percent)/MWCNTs anode shows the highest electrochemical performance among them and will be a promising material for improving bioelectricity production of the BMFCs. Finally, a synergistic mechanism of electron transfer shuttle of Mn ions and their redox reactions in the interface between modified anode and bacteria biofilm are proposed to explain its excellent electrochemical performance.

  6. Ecosystem services of boreal forests - Carbon budget mapping at high resolution.

    Science.gov (United States)

    Akujärvi, Anu; Lehtonen, Aleksi; Liski, Jari

    2016-10-01

    The carbon (C) cycle of forests produces ecosystem services (ES) such as climate regulation and timber production. Mapping these ES using simple land cover -based proxies might add remarkable inaccuracy to the estimates. A framework to map the current status of the C budget of boreal forested landscapes was developed. The C stocks of biomass and soil and the annual change in these stocks were quantified in a 20 × 20 m resolution at the regional level on mineral soils in southern Finland. The fine-scale variation of the estimates was analyzed geo-statistically. The reliability of the estimates was evaluated by comparing them to measurements from the national multi-source forest inventory. The C stocks of forests increased slightly from the south coast to inland whereas the changes in these stocks were more uniform. The spatial patches of C stocks were larger than those of C stock changes. The patch size of the C stocks reflected the spatial variation in the environmental conditions, and that of the C stock changes the typical area of forest management compartments. The simulated estimates agreed well with the measurements indicating a good mapping framework performance. The mapping framework is the basis for evaluating the effects of forest management alternatives on C budget at high resolution across large spatial scales. It will be coupled with the assessment of other ES and biodiversity to study their relationships. The framework integrated a wide suite of simulation models and extensive inventory data. It provided reliable estimates of the human influence on C cycle in forested landscapes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Linking Intertidal and Subtidal Food Webs: Consumer-Mediated Transport of Intertidal Benthic Microalgal Carbon

    OpenAIRE

    Chang-Keun Kang; Hyun Je Park; Eun Jung Choy; Kwang-Sik Choi; Kangseok Hwang; Jong-Bin Kim

    2015-01-01

    We examined stable carbon and nitrogen isotope ratios for a large variety of consumers in intertidal and subtidal habitats, and their potential primary food sources [i.e., microphytobenthos (MPB), phytoplankton, and Phragmites australis] in a coastal bay system, Yeoja Bay of Korea, to test the hypothesis that the transfer of intertidal MPB-derived organic carbon to the subtidal food web can be mediated by motile consumers. Compared to a narrow δ13C range (-18 to -16‰) of offshore consumers, a...

  8. A simple method for air/sea gas exchange measurement in mesocosms and its application in carbon budgeting

    Directory of Open Access Journals (Sweden)

    J. Czerny

    2012-09-01

    Full Text Available Mesocosms as large experimental vessels principally provide the opportunity of performing elemental budget calculations e.g. to derive net biological turnover rates. However, the system is in most cases not closed at the water surface and gases can exchange with the atmosphere. Previous attempts to budget carbon pools in mesocosms relied on educated guesses concerning the exchange of CO2 with the atmosphere. Nevertheless, net primary production rates derived from these budget calculations were, despite large uncertainties in air/sea gas exchange, often more reasonable than cumulative extrapolations of bioassays. While bioassays have limitations representing the full spectrum of trophic levels and abiotic conditions inside the mesocosms, calculating dissolved inorganic carbon uptake inside the mesocosms has the potential to deliver net community production rates representative of the enclosed system. Here, we present a simple method for precise determination of air/sea gas exchange velocities in mesocosms using N2O as a deliberate tracer. Beside the application for carbon budgeting, exchange velocities can be used to calculate exchange rates of any gas of known concentration, e.g. to calculate aquatic production rates of climate relevant trace gases. Using an arctic (Kiel Off Shore Mesocosms for future Ocean Simulation mesocosm experiment as an exemplary dataset, it is shown that application of the presented method largely improves accuracy of carbon budget estimates. Methodology of manipulation, measurement, data processing and conversion to CO2 fluxes are explained. A theoretical discussion of prerequisites for precise gas exchange measurements provides a guideline for the applicability of the method under various experimental conditions.

  9. Afforestation contribution to Carbon and Nitrogen budgets of forest in a natural park in south Spain

    Science.gov (United States)

    Lozano-García, Beatriz; Parras-Alcántara, Luis

    2015-04-01

    Forests are important ecosystems because they provide wood products to society as well as many services (recreation, habitat functions, the regulation of water, erosion, and air quality). However, the society has recently focused its attention on forests for two reasons; sequestration of carbon, on the one hand, and provision of biomass for bioenergy, on the other, also illustrates the possible trade-off even within the theme of climate change mitigation. Due to this fact, the forest surface has increased in Spain, as well in Europe in the last decades. The area covered by forest represents 34% in Europe and 35.6% in Spain compared to the total surface. A powerful afforestation policy was carried out in Spain from the 40's decade in forward. The main objective was to increase the forest surface with trees. Two main actions were developed under these repopulations, the transformation of pasture land in forest, on the one hand, and the introduction of fast-growing tree species, on the second hand. Therefore, currently, there are a lot of forest areas in Spain in which the introduced species coexist with native. In addition, the spatial variation of soil properties is significantly influenced by some environmental factors such as topographic aspect that induced microclimate differences, topographic (landscape) positions, parent materials, and vegetation communities. Topographic aspect induces local variation in temperature and precipitation solar radiation and relative humidity, which along with chemical and physical composition of the substrate, are the main regulators of decomposition rates of organic matter. The aim of this study were, i) to evaluate the effect of afforestation policies on carbon and nitrogen budgets in a natural park in Spain and ii) to study the topographic aspect effect on the capacity of SOC and N storage. Our results show how the afforestated areas (in which there are simultaneously both, natural species and introduced species) had higher soil

  10. Direct comparison of repeated soil inventory and carbon flux budget to detect soil carbon stock changes in grassland

    Science.gov (United States)

    Ammann, C.; Leifeld, J.; Neftel, A.; Fuhrer, J.

    2012-04-01

    Experimental assessment of soil carbon (C) stock changes over time is typically based on the application of either one of two methods, namely (i) repeated soil inventory and (ii) determination of the ecosystem C budget or net biome productivity (NBP) by continuous measurement of CO2 exchange in combination with quantification of other C imports and exports. However, there exist hardly any published study hitherto that directly compared the results of both methods. Here, we applied both methods in parallel to determine C stock changes of two temperate grassland fields previously converted from long-term cropland. The grasslands differed in management intensity with either intensive management (high fertilization, frequent cutting) or extensive management (no fertilization, less frequent cutting). Soil organic C stocks (0-45 cm depth) were quantified at the beginning (2001) and the end (2006) of a 5 year observational period using the equivalent soil mass approach. For the same period and in both fields, NBP was quantified from net CO2 fluxes monitored using eddy covariance systems, and measured C import by organic fertilizer and C export by harvest. Both NBP and repeated soil inventories revealed a consistent and significant difference between management systems of 170 ± 48 and 253 ± 182 g C m-2 a-1, respectively. For both fields, the inventory method showed a tendency towards higher C loss/smaller C gain than NBP. In the extensive field, a significant C loss was observed by the inventory but not by the NBP approach. Thus both, flux measurements and repeated soil sampling, seem to be adequate and equally suited for detecting relative management effects. However, the suitability for tracking absolute changes in SOC could not be proven for neither of the two methods. Overall, our findings stress the need for more direct comparisons to evaluate whether the observed difference in the outcome of the two approaches reflects a general methodological bias, which would

  11. Seasonal carbon cycling in a Greenlandic fjord: an integrated pelagic and benthic study

    DEFF Research Database (Denmark)

    Sørensen, Heidi Louise; Meire, Lorenz; Juul-Pedersen, Thomas;

    2015-01-01

    Climate change is expected to have a pronounced effect on biogeochemical cycling in Arctic fjords, but current insight on the biogeochemical functioning of these systems is limited. Here, we present seasonal data on primary production, export of particulate organic carbon (POC), and the coupling...

  12. Incorporation of uranium in benthic foraminiferal calcite reflects seawater carbonate ion concentration

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Nehrke, G.; Reichart, G.-J.; Bijma, J.

    2013-01-01

    The chemical and isotopic composition of foraminiferal shells (so-called proxies) reflects the physicochemical properties of the seawater. In current day paleoclimate research, the reconstruction of past seawater carbonate system to infer atmospheric CO2 concentrations is one of the most

  13. Incorporation of uranium in benthic foraminiferal calcite reflects seawater carbonate ion concentration

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Nehrke, G.; Reichart, G.-J.; Bijma, J.

    2013-01-01

    The chemical and isotopic composition of foraminiferal shells (so-called proxies) reflects the physicochemical properties of the seawater. In current day paleoclimate research, the reconstruction of past seawater carbonate system to infer atmospheric CO2 concentrations is one of the most pressing

  14. Incorporation of uranium in benthic foraminiferal calcite reflects seawater carbonate ion concentration

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Nehrke, G.; Reichart, G.-J.; Bijma, J.

    2013-01-01

    The chemical and isotopic composition of foraminiferal shells (so-called proxies) reflects the physicochemical properties of the seawater. In current day paleoclimate research, the reconstruction of past seawater carbonate system to infer atmospheric CO2 concentrations is one of the most pressing ch

  15. Carbon flows through a benthic food web: Integrating biomass, isotope and tracer data

    NARCIS (Netherlands)

    Van Oevelen, D.; Soetaert, K.E.R.; Middelburg, J.J.; Herman, P.M.J.; Moodley, L.; Hamels, I.; Moens, T.; Heip, C.H.R.

    2006-01-01

    The herbivorous, detrital and microbial pathways are major components of marine food webs. Although it is commonly recognized that these pathways can be linked in several ways, elucidating carbon transfers between or within these pathways remains a challenge. Intertidal flat communities are driven b

  16. Incorporation of uranium in benthic foraminiferal calcite reflects seawater carbonate ion concentration

    NARCIS (Netherlands)

    Keul, N.; Langer, G.; de Nooijer, L.J.; Nehrke, G.; Reichart, G.-J.; Bijma, J.

    2013-01-01

    The chemical and isotopic composition of foraminiferal shells (so-called proxies) reflects the physicochemical properties of the seawater. In current day paleoclimate research, the reconstruction of past seawater carbonate system to infer atmospheric CO2 concentrations is one of the most pressing ch

  17. Seasonal carbon cycling in a Greenlandic fjord: an integrated pelagic and benthic study

    NARCIS (Netherlands)

    Sørensen, H.L.; Meire, L.; Juul-Pedersen, T.; de Stigter, H.C.; Meysman, F.J.R.; Rysgaard, S.; Thamdrup, B.; Glud, R.N.

    2015-01-01

    Climate change is expected to have a pronounced effect on biogeochemical cycling in Arctic fjords, but current insight on the biogeochemical functioning of these systems is limited. Here, we present seasonal data on primary production, export of particulate organic carbon (POC), and the coupling to

  18. Carbon, nitrogen, and phosphorus budget in scampi (Macrobrachium rosenbergii) culture ponds.

    Science.gov (United States)

    Sahu, Bharat Chandra; Adhikari, Subhendu; Mahapatra, Abhijit S; Dey, Lambodar

    2013-12-01

    Experiments were conducted for the study of nutrient budget in ten farmer's ponds (0.2-0.5 ha) in Orissa, India with a mean water depth of 1.0-1.2 m. Scampi (Macrobrachium rosenbergii) were stocked in these ponds at stocking density of 3.75-5.0/m(2). The average initial body weight of scampi was 0.02 mg. The culture period was for 4 months. Feed was the main input. Total feed applied to these ponds ranged from 945 to 2261 kg pond/cycle (crop). The feed conversion ratio varied 1.65 to 1.78. In addition to feed, rice straw, urea, and single super phosphate were applied to these ponds in small amounts for plankton production. At harvest time, the average weight of scampi varied from 60-90 g. The budget showed that feed was the major input of nitrogen (N), phosphorus (P), and carbon in these ponds. The inorganic fertilizer (urea and single super phosphate), organic fertilizer (rice straw and yeast extract), and inlet water, either from the initial fills or from rainwater, were the source of all other N, P, and organic carbon (OC) to these ponds. Total N applied to these ponds through all these inputs ranged from 44.45 to 103.98 kg N per crop, 12.23 to 28.79 kg P per crop, and from 381.54 to 905.22 kg OC per crop, respectively. Among all the inputs, feed alone accounted for 95.34 % N, 97.98 % P, and 94.27 % OC, respectively. Recovery of 16.34 to 38.66 kg N (average 29.27 kg), 1.28 to 3.02 kg P (average 2.29 kg), and 63.21 to 149.51 kg OC (average 113.20 kg), respectively, by the scampi harvest were observed in these ponds. Thus, harvest of scampi accounted for recovery of 35.18 to 39.01 (average 36.85%) of added N, 10.09 to 10.97 (average 10.44%) of added P, and 7.57 to 17.12 (average 16.34%) of added OC, respectively.

  19. New insight into the atmospheric chloromethane budget gained using stable carbon isotope ratios

    Directory of Open Access Journals (Sweden)

    F. Keppler

    2005-01-01

    Full Text Available Atmospheric chloromethane (CH3Cl plays an important role in stratospheric ozone destruction, but many uncertainties still exist regarding strengths of both sources and sinks and the processes leading to formation of this naturally occurring gas. Recent work has identified a novel chemical origin for CH3Cl, which can explain its production in a variety of terrestrial environments: the widespread structural component of plants, pectin, reacts readily with chloride ion to form CH3Cl at both ambient and elevated temperatures (Hamilton et al., 2003. It has been proposed that this abiotic chloride methylation process in terrestrial environments could be responsible for formation of a large proportion of atmospheric CH3Cl. However, more information is required to determine the global importance of this new source and its contribution to the atmospheric CH3Cl budget. A potentially powerful tool in studying the atmospheric CH3Cl budget is the use of stable carbon isotope ratios. In an accompanying paper it is reported that the reaction of CH3Cl with OH radical, the dominant sink for atmospheric CH3Cl, is accompanied by an unexpectedly large fractionation factor (Gola et al., 2005. Another recently published study shows that CH3Cl formed by the abiotic methylation process at ambient temperatures has a unique stable carbon isotope signature, extremely depleted in 13C, unequivocally distinguishing it from all other known sources (Keppler et al., 2004. Using these findings together with data existing in the literature, we here present three scenarios for an isotopic mass balance for atmospheric CH3Cl. Our calculations provide strong support for the proposal that the largest source of atmospheric CH3Cl (1800 to 2500 Gg yr-1 is the abiotic methylation of chloride in terrestrial ecosytems, primarily located in tropical and subtropical areas where turnover of biomass is highest. Furthermore our calculations also indicate that the microbial soil sink for CH3Cl is

  20. Corn Belt soil carbon and macronutrient budgets with projected sustainable stover harvest

    Science.gov (United States)

    Tan, Zhengxi; Liu, Shu-Guang

    2015-01-01

    Corn (Zea mays L.) stover has been identified as a prime feedstock for biofuel production in the U.S. Corn Belt because of its perceived abundance and availability, but long-term stover harvest effects on regional nutrient budgets have not been evaluated. We defined the minimum stover requirement (MSR) to maintain current soil organic carbon levels and then estimated current and future soil carbon (C), nitrogen (N), phosphorus (P), and potassium (K) budgets for various stover harvest scenarios. Analyses for 2006 through 2010 across the entire Corn Belt indicated that currently, 28 Tg or 1.6 Mg ha−1 of stover could be sustainably harvested from 17.95 million hectares (Mha) with N, P, and K removal of 113, 26, and 47 kg ha−1, respectively, and C removal for that period was estimated to be 4.55 Mg C ha−1. Assuming continued yield increases and a planted area of 26.74 Mha in 2050, 77.4 Tg stover (or 2.4 Mg ha−1) could be sustainably harvested with N, P, and K removal of 177, 37, and 72 kg ha−1, respectively, along with C removal of ∼6.57 Mg C ha−1. Although there would be significant variation across the region, harvesting only the excess over the MSR under current fertilization rates would result in a small depletion of soil N (−5 ± 27 kg ha−1) and K (−20 ± 31 kg ha−1) and a moderate surplus of P (36 ± 18 kg ha−1). Our 2050 projections based on continuing to keep the MSR, but having higher yields indicate that soil N and K deficits would become larger, thus emphasize the importance of balancing soil nutrient supply with crop residue removal.

  1. Disturbances in Russian Forests in 1950-2000: Impact on the Carbon Budget

    Science.gov (United States)

    Shvidenko, A.; Nilsson, S.; Apps, M.; Maksyutov, S.

    2001-12-01

    Major types of natural and human induced disturbances (D) on Russian forest land (FL, 882x106 ha in 1998), i.e. fire, insect and diseases, harvest, industrial transformation, pollution and other abiotic factors, are quantified for 1950--2000 based on different surveys and other available sources in terms of a unified system of indicators on disturbance regimes (Shvidenko \\textit{et al}., 2001). Due to the lack of long-term direct monitoring of D, a number of auxiliary models was developed in order to estimate the extent and severity of D for all Russian FL at the regional level based on available measured indicators. Dynamics of disturbed areas by different types of D present non-stationary stochastic processes with significant variability (up to 10 fold) and long-term trends characteristic for individual types of D. Regional weather conditions define to a large extent the spatial distribution of major natural D (fires and insect outbreaks), which annually are concentrated in 34 regions. During the period considered, D affected on average for the entire time period about 12x106 haṡyr-1, of which fires damaged 5.0x106 haṡyr-1, insect infestation and diseases 4.0x106 haṡyr-1, and harvest 1.8x106 haṡyr-1. Impacts of D on the carbon budget were estimated based on a model applicable to all D types. The model considers the annual carbon flux of \\textit{the ecosystem-atmosphere exchange} generated by each particular type of disturbance ρ as a function of the direct emission during a year t1 and the post-disturbance, as a rule, biogenic fluxes generated by disturbance ρ that occurred during previous years tformalized. The interaction of different types of D in the framework of individual DR is described by empirical functions. The summarized annual average D flux is estimated in the range of 100 to 350 Tg C yr-1, with an average for the entire period of about 200 Tg C yr-1. The input of different D types varies greatly, e.g., direct fire emissions vary from 20

  2. Drought as a Disturbance: Implications for Peatland Carbon Budgets in the Hudson Bay Lowland

    Science.gov (United States)

    Bello, R.; Abnizova, A.; Miller, E.

    2009-05-01

    Carbon feedbacks are of particular importance in high latitudes, both because of large circumpolar peatland carbon pools and because climate warming is occurring more rapidly at these latitudes. Longer-term net ecosystem exchange will be influenced by the capacity of plant communities to respond to changing conditions. The nature of community change and the factors inducing change are examined in this study of a disturbance generated by severe drought in 1994 causing widespread mortality in the dominant moss, Dicranum elongatum, occupying an upland tundra site within the Hudson Bay Lowland near Churchill, Manitoba. One quarter of this moss has recently died and become encrusted with the micro-lichen, Ochrolechia spp. Moss cushions affected in this manner exhibit strong allelopathic inhibition of seedling establishment progressing to complete moss decay. Chamber NEE growing-season flux measurements show an average net release of 642 mg C /m2/d from the dead moss compared to an average net uptake of 164 mg C /m2/d from completely healthy cushions. Between these two extremes, stressed living moss cushions support abundant seedling cover which increases in direct proportion with the fractional mortality. A proxy method for estimating the growth rates of cushions, based on the length of green living shoots, indicates that the moss community is uniform in age and established shortly after the most severe drought of historical record in 1966. Subsequent growth rates of cushions show a strong dependency on proximity to the water table (4.17-1.11 mm/y over 58 cm height interval). A growing-season moss water budget identifies the dominant water flow pathways and indicates capillary uptake (0.08 mm h-1) provides 64% of the storage gains, emphasizing the importance of groundwater for growth and survival. Maximum storage capacities are directly related to cushion biomass, leading to both enhanced moisture stress and increased susceptibility to mortality as cushion size

  3. Benthic Cover

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic cover (habitat) maps are derived from aerial imagery, underwater photos, acoustic surveys, and data gathered from sediment samples. Shallow to moderate-depth...

  4. No changes in contributions of echinoderms to the carbon budgets in shelf seas of China over the past five decades

    Science.gov (United States)

    Jin, Shaofei; Yan, Xiaodong; Zhang, Heng; Xiao, Ning; Zhang, Junlong; Liu, Wenliang; Xiong, Zhe

    2015-09-01

    The contribution over the past five decades of echinoderms to the regional carbon cycle of shelf sea areas in China, as well as the changes in calcium carbonate (CaCO3)/calcium carbonate carbon (CaCO3-C) standing stocks and production rates, was investigated using meta-analysis. We report results for water depths of echinoderm biomasses, and total macrobenthos biomasses showed no significant linear decline, but there was a significant decline for the biomass ratio of echinoderms to total macrobenthic biomass since the 1950s. However, there remain no convincing evidences to explain this due to a lack of environmental data. We suggest that studies on the responses of echinoderms to intense anthropogenic activities and climate change should concentrate on their roles in carbon budgets and macrobenthos community stability.

  5. Technical Note: A simple method for air–sea gas exchange measurements in mesocosms and its application in carbon budgeting

    Directory of Open Access Journals (Sweden)

    J. Czerny

    2013-03-01

    Full Text Available Mesocosms as large experimental units provide the opportunity to perform elemental mass balance calculations, e.g. to derive net biological turnover rates. However, the system is in most cases not closed at the water surface and gases exchange with the atmosphere. Previous attempts to budget carbon pools in mesocosms relied on educated guesses concerning the exchange of CO2 with the atmosphere. Here, we present a simple method for precise determination of air–sea gas exchange in mesocosms using N2O as a deliberate tracer. Beside the application for carbon budgeting, transfer velocities can be used to calculate exchange rates of any gas of known concentration, e.g. to calculate aquatic production rates of climate relevant trace gases. Using an arctic KOSMOS (Kiel Off Shore Mesocosms for future Ocean Simulation experiment as an exemplary dataset, it is shown that the presented method improves accuracy of carbon budget estimates substantially. Methodology of manipulation, measurement, data processing and conversion to CO2 fluxes are explained. A theoretical discussion of prerequisites for precise gas exchange measurements provides a guideline for the applicability of the method under various experimental conditions.

  6. Contaminant Interactions and Biological Effects of Single-walled Carbon Nanotubes in a Benthic Estuarine System

    Science.gov (United States)

    Parks, Ashley Nicole

    The fate, bioavailability, bioaccumulation and toxicity of single-walled carbon nanotubes (SWNT) have not been extensively studied to date. Pristine SWNT are highly hydrophobic and have been shown to strongly associate with natural particulate matter in aquatic environments. In light of this, I have focused my research to examine the influence of sediment and food exposure routes on bioavailability, bioaccumulation, and toxicity of structurally diverse SWNT in several ecologically-important marine invertebrate species. No significant mortality was observed in any organism at concentrations up to 1000 mg/kg. Evidence of biouptake after ingestion was observed for pristine semiconducting SWNT using NIRF spectroscopy and for oxidized 14C-SWNT using liquid scintillation counting. After a 24 hour depuration period, the pristine semiconducting SWNT were eliminated from organisms to below the method detection limit (5 microg/mL), and the 14C-SWNT body burden was decreased by an order of magnitude to a bioaccumulation factor (BAF) of polychlorinated biphenyls (PCBs), was amended with pristine SWNT to determine if the presence of SWNT would mitigate the toxicity and bioaccumulation of the PCBs in deposit-feeding invertebrates. A dilution series of the NBH sediment was created using uncontaminated Long Island Sound (LIS) sediment to test 25% NBH sediment, 50% NBH sediment, 75% NBH sediment, and 100% NBH sediment. The results of this work showed increased organism survival and decreased bioaccumulation of PCBs in treatments amended with SWNT, with the greatest reduction observed in the 25% NBH sediment treatment group amended with 10 mg SWNT/g dry sediment. Polyethylene (PE) passive samplers indicated a reduction of interstitial water (ITW) PCB concentration of greater than 90% in the 25% NBH sediment + 10 mg SWNT/g dry sediment amendment. The ITW concentration was reduced because PCBs were not desorbing from the SWNT. Lower bioavailability leads to reduced potential for toxic

  7. Taking climate, land use, and social economy into estimation of carbon budget in the Guanzhong-Tianshui Economic Region of China.

    Science.gov (United States)

    Li, Ting; Li, Jing; Zhou, Zixiang; Wang, Yanze; Yang, Xiaonan; Qin, Keyu; Liu, Jingya

    2017-04-01

    Carbon sequestration is an indispensable ecosystem service provided by soil and vegetation, so mapping and valuing the carbon budget by considering both ecological and social factors is an important trend in evaluating ecosystem services. In this work, we established multiple scenarios to evaluate the impacts of land use change, population growth, carbon emission per capita, and carbon markets on carbon budget. We quantified carbon sinks (aboveground and belowground) under different scenarios, using the Carnegie-Ames-Stanford Approach (CASA) model and an improved carbon cycle process model, and studied carbon sources caused by human activities by analyzing the spatial distribution of human population and carbon emission per capita. We also assessed the net present value (NPV) for carbon budgets under different carbon price and discount rate scenarios using NPV model. Our results indicate that the carbon budget of Guanzhong-Tianshui Economic Region is surplus: Carbon sinks range from 1.50 × 10(10) to 1.54 × 10(10) t, while carbon sources caused by human activities range from 2.76 × 10(5) to 7.60 × 10(5) t. And the NPV for carbon deficits range from 3.20 × 10(11) RMB to 1.52 × 10(12) RMB. From the perspective of ecological management, deforestation, urban sprawl, population growth, and excessive carbon consumption are considered as the main challenges in balancing carbon sources and sinks. Levying carbon tax would be a considerable option when decision maker develops carbon emission reduction policies. Our results provide a scientific and credible reference for harmonious and sustainable development in the Guanzhong-Tianshui Economic Region of China.

  8. Carbon budgets of three temperate forest ecosystems in Dongling Mt., Beijing, China

    Institute of Scientific and Technical Information of China (English)

    FANG JingYun; LIU GuoHua; ZHU Biao; WANG XiaoKe; LIU ShaoHui

    2007-01-01

    There is a general agreement that forest ecosystems in the Northern Hemisphere function as significant sinks for atmospheric CO2; however, their magnitude and distribution remain large uncertainties. In this paper, we report the carbon (C) stock and its change of vegetation, forest floor detritus, and mineral soil, annual net biomass increment and litterfall production, and respiration of vegetation and soils between 1992 to 1994, for three temperate forest ecosystems, birch (Betula platyphylla) forest, oak (Quercus liaotungensis) forest and pine (Pinus tabulaeformis) plantation in Mt. Dongling, Beijing, China. We then evaluate the C budgets of these forest ecosystems. Our results indicated that total C density (organic C per hectare) of these forests ranged from 250 to 300 t C ha-1, of which 35―54 t C ha-1 from vegetation biomass C and 209―244 t C ha-1 from soil organic C (1 m depth, including forest floor detritus). Biomass C of all three forests showed a net increase, with 1.33―3.55 t C ha-1 a-1 during the study period. Litterfall production, vegetation autotrophic respiration, and soil heterotrophic respiration were estimated at 1.63―2.34, 2.19―6.93, and 1.81―3.49 t C ha-1 a-1, respectively. Ecosystem gross primary production fluctuated between 5.39 and 12.82 t C ha-1 a-1, about half of which (46%―59%, 3.20―5.89 t C ha-1 a-1) was converted to net primary production. Our results suggested that pine forest fixed C of 4.08 t ha-1 a-1, whereas secondary forests (birch and oak forest) were nearly in balance in CO2 exchange between the atmosphere and ecosystems.

  9. Carbon budgets of three temperate forest ecosystems in Dongling Mt.,Beijing,China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    There is a general agreement that forest ecosystems in the Northern Hemisphere function as signifi-cant sinks for atmospheric CO2; however, their magnitude and distribution remain large uncertainties. In this paper, we report the carbon (C) stock and its change of vegetation, forest floor detritus, and mineral soil, annual net biomass increment and litterfall production, and respiration of vegetation and soils between 1992 to 1994, for three temperate forest ecosystems, birch (Betula platyphylla) forest, oak (Quercus liaotungensis) forest and pine (Pinus tabulaeformis) plantation in Mt. Dongling, Beijing, China. We then evaluate the C budgets of these forest ecosystems. Our results indicated that total C density (organic C per hectare) of these forests ranged from 250 to 300 t C ha-1, of which 35―54 t C ha-1 from vegetation biomass C and 209―244 t C ha-1 from soil organic C (1 m depth, including forest floor detritus). Biomass C of all three forests showed a net increase, with 1.33―3.55 t C ha-1 a-1 during the study period. Litterfall production, vegetation autotrophic respiration, and soil heterotrophic respira-tion were estimated at 1.63―2.34, 2.19―6.93, and 1.81―3.49 t C ha-1 a-1, respectively. Ecosystem gross primary production fluctuated between 5.39 and 12.82 t C ha-1 a-1, about half of which (46%―59%, 3.20―5.89 t C ha-1 a-1) was converted to net primary production. Our results suggested that pine forest fixed C of 4.08 t ha-1 a-1, whereas secondary forests (birch and oak forest) were nearly in balance in CO2 exchange between the atmosphere and ecosystems.

  10. Soil greenhouse gas emissions and carbon budgeting in a short-hydroperiod floodplain wetland

    Science.gov (United States)

    Batson, Jackie; Noe, Gregory B.; Hupp, Cliff R.; Krauss, Ken W.; Rybicki, Nancy B.; Schenk, Edward R.

    2015-01-01

    Understanding the controls on floodplain carbon (C) cycling is important for assessing greenhouse gas emissions and the potential for C sequestration in river-floodplain ecosystems. We hypothesized that greater hydrologic connectivity would increase C inputs to floodplains that would not only stimulate soil C gas emissions but also sequester more C in soils. In an urban Piedmont river (151 km2 watershed) with a floodplain that is dry most of the year, we quantified soil CO2, CH4, and N2O net emissions along gradients of floodplain hydrologic connectivity, identified controls on soil aerobic and anaerobic respiration, and developed a floodplain soil C budget. Sites were chosen along a longitudinal river gradient and across lateral floodplain geomorphic units (levee, backswamp, and toe slope). CO2 emissions decreased downstream in backswamps and toe slopes and were high on the levees. CH4 and N2O fluxes were near zero; however, CH4emissions were highest in the backswamp. Annual CO2 emissions correlated negatively with soil water-filled pore space and positively with variables related to drier, coarser soil. Conversely, annual CH4 emissions had the opposite pattern of CO2. Spatial variation in aerobic and anaerobic respiration was thus controlled by oxygen availability but was not related to C inputs from sedimentation or vegetation. The annual mean soil CO2 emission rate was 1091 g C m−2 yr−1, the net sedimentation rate was 111 g C m−2 yr−1, and the vegetation production rate was 240 g C m−2 yr−1, with a soil C balance (loss) of −338 g C m−2 yr−1. This floodplain is losing C likely due to long-term drying from watershed urbanization.

  11. Insights into the coupling of upper ocean-benthic carbon dynamics in the western Arctic Ocean from an isotopic (13C,234Th) perspective

    Institute of Scientific and Technical Information of China (English)

    ZHANG Run; CHEN Min; MA Qiang; CAO Jianping; QIU Yusheng

    2015-01-01

    The coupling of upper ocean-benthic carbon dynamics in the ice-free western Arctic Ocean (the Chukchi Sea and the Canada Basin) was evaluated during the late July–early September 2003 using natural stable (13C) and radioactive (238U-234Th) isotope tracers. POC export flux estimated from234Th/238U disequilibria and dissolved CO2 concentration ([CO2(aq)]) pointed out that the strengthened biological pump in the Chukchi Shelf have significantly lowered [CO2(aq)] and altered the magnitude of isotopic (12C/13C) fractionation during carbon fixation in the surface ocean. Further,d13C signatures of surface sediments (d13Csed) are positively correlated to those of weightedd13CPOC in upper ocean (d13Csed =13.64+1.56×d13CPOC,r2=0.73,p<0.01), suggesting that the POC isotopic signals from upper ocean have been recorded in the sediments, partly due to the rapid export of particles as evidenced by low residence times of the highly particle-reactive234Th from the upper water column. It is suggested that there probably exists an upper ocean-benthic coupling of carbon dynamics, which likely assures the sedimentaryd13C record an indicator of paleo-CO2 in the western Arctic Ocean.

  12. The European forest sector: past and future carbon budget and fluxes under different management scenarios

    Science.gov (United States)

    Pilli, Roberto; Grassi, Giacomo; Kurz, Werner A.; Fiorese, Giulia; Cescatti, Alessandro

    2017-05-01

    The comprehensive analysis of carbon stocks and fluxes of managed European forests is a prerequisite to quantify their role in biomass production and climate change mitigation. We applied the Carbon Budget Model (CBM) to 26 European countries, parameterized with country information on the historical forest age structure, management practices, harvest regimes and the main natural disturbances. We modeled the C stocks for the five forest pools plus harvested wood products (HWPs) and the fluxes among these pools from 2000 to 2030. The aim is to quantify, using a consistent modeling framework for all 26 countries, the main C fluxes as affected by land-use changes, natural disturbances and forest management and to assess the impact of specific harvest and afforestation scenarios after 2012 on the mitigation potential of the EU forest sector. Substitution effects and the possible impacts of climate are not included in this analysis. Results show that for the historical period from 2000 to 2012 the net primary productivity (NPP) of the forest pools at the EU level is on average equal to 639 Tg C yr-1. The losses are dominated by heterotrophic respiration (409 Tg C yr-1) and removals (110 Tg C yr-1), with direct fire emissions being only 1 Tg C yr-1, leading to a net carbon stock change (i.e., sink) of 110 Tg C yr-1. Fellings also transferred 28 Tg C yr-1 of harvest residues from biomass to dead organic matter pools. The average annual net sector exchange (NSE) of the forest system, i.e., the carbon stock changes in the forest pools including HWP, equals a sink of 122 Tg C yr-1 (i.e., about 19 % of the NPP) for the historical period, and in 2030 it reaches 126, 101 and 151 Tg C yr-1, assuming constant, increasing (+20 %) and decreasing (-20 %) scenarios, respectively, of both harvest and afforestation rates compared to the historical period. Under the constant harvest rate scenario, our findings show an incipient aging process of the forests existing in 1990: although NPP

  13. Annual variation in carbon budget using remote-sensing data and a process model in Borneo Island, Southeast Asia

    Science.gov (United States)

    Adachi, M.; Ito, A.; Takeuchi, W.; Yamagata, Y.

    2011-12-01

    Reducing emissions from deforestation and forest degradation in developing countries (REDD) is one of the most important carbon emission reduction efforts in the tropical region. Deforestation and land use changes are human activities with major impact on the regional carbon budged and the other greenhouse gases (CH4 and N2O) emissions. Forest carbon biomass in Southeast Asia is largest in Asia region; however, the area of primary forest had continuously decreased due to land-use conversion. The objective of the present study was to evaluate carbon budged and greenhouse gases induced by deforestation from Borneo Island. We used time-series satellite remote-sensing data to track deforestation history in Borneo Island, Southeast Asia, and estimated the resulting forest carbon budget using a process-based model (VISIT: Vegetation Integrative SImulator for Trace gases). The forest/non-forest area was mapped by applying the ALOS/PALSAR-calibrated threshold value to MODIS, SPOT-VEGETATION, and NOAA-AVHRR images. The model allowed us to estimate changes in carbon budged and greenhouse gases by human disturbances, including land-use conversion from primary forest to cropland (e.g., oil-palm plantation). The estimated carbon stocks, budged, and greenhouse gases were verified using field observation of previous studies at some point of Borneo Island. Our results suggested that the southern part of Borneo Island was a large carbon source due to deforestation, although the VISIT model need be revised to account for tropical peatland.

  14. Assessing the carbon sink of afforestation with the Carbon Budget Model at the country level: an example for Italy

    Directory of Open Access Journals (Sweden)

    Pilli R

    2015-08-01

    Full Text Available In the context of the Kyoto Protocol, the mandatory accounting of Afforestation and Reforestation (AR activities requires estimating the forest carbon (C stock changes for any direct human-induced expansion of forest since 1990. We used the Carbon Budget Model (CBM to estimate C stock changes and emissions from fires on AR lands at country level. Italy was chosen because it has one of the highest annual rates of AR in Europe and the same model was recently applied to Italy’s forest management area. We considered the time period 1990-2020 with two case studies reflecting different average annual rates of AR: 78 kha yr-1, based on the 2013 Italian National Inventory Report (NIR, official estimates, and 28 kha yr-1, based on the Italian Land Use Inventory System (IUTI estimates. We compared these two different AR rates with eight regional forest inventories and three independent local studies. The average annual C stock change estimated by CBM, excluding harvest or natural disturbances, was equal to 1738 Gg C yr-1 (official estimates and 630 Gg C yr-1 (IUTI estimates. Results for the official estimates are consistent with the estimates reported by Italy to the KP for the period 2008-2010; for 2011 our estimates are about 20% higher than the country’s data, probably due to different assumptions on the fire disturbances, the AR rate and the dead wood and litter pools. Furthermore, our analysis suggests that: (i the impact on the AR sink of different assumptions of species composition is small; (ii the amount of harvest provided by AR has been negligible for the past (< 3% and is expected to be small in the near future (up to 8% in 2020; (iii forest fires up to 2011 had a small impact on the AR sink (on average, < 100 Gg C yr-1. Finally the comparison of the historical AR rates reported by NIR and IUTI with other independent sources gives mixed results: the regional inventories support the AR rates reported by the NIR, while some local studies

  15. Simulating the carbon, water, energy budgets and greenhouse gas emissions of arctic soils with the ISBA land surface model

    Science.gov (United States)

    Morel, Xavier; Decharme, Bertrand; Delire, Christine

    2017-04-01

    Permafrost soils and boreal wetlands represent an important challenge for future climate simulations. Our aim is to be able to correctly represent the most important thermal, hydrologic and carbon cycle related processes in boreal areas with our land surface model ISBA (Masson et al, 2013). This is particularly important since ISBA is part of the CNRM-CM Climate Model (Voldoire et al, 2012), that is used for projections of future climate changes. To achieve this goal, we replaced the one layer original soil carbon module based on the CENTURY model (Parton et al, 1987) by a multi-layer soil carbon module that represents C pools and fluxes (CO2 and CH4), organic matter decomposition, gas diffusion (Khvorostyanov et al., 2008), CH4 ebullition and plant-mediated transport, and cryoturbation (Koven et al., 2009). The carbon budget of the new model is closed. The soil carbon module is tightly coupled to the ISBA energy and water budget module that solves the one-dimensional Fourier law and the mixed-form of the Richards equation explicitly to calculate the time evolution of the soil energy and water budgets (Boone et al., 2000; Decharme et al. 2011). The carbon, energy and water modules are solved using the same vertical discretization. Snowpack processes are represented by a multi-layer snow model (Decharme et al, 2016). We test this new model on a pair of monitoring sites in Greenland, one in a permafrost area (Zackenberg Ecological Research Operations, Jensen et al, 2014) and the other in a region without permafrost (Nuuk Ecological Research Operations, Jensen et al, 2013); both sites are established within the GeoBasis part of the Greenland Ecosystem Monitoring (GEM) program. The site of Chokurdakh, in a permafrost area of Siberia is is our third studied site. We test the model's ability to represent the physical variables (soil temperature and water profiles, snow height), the energy and water fluxes as well as the carbon dioxyde and methane fluxes. We also test the

  16. Impacts of Colonial Deforestation on Sediment Organic Carbon Fluxes and Budget Using Black Carbon Chronology: Waiapu Continental Shelf, New Zealand

    Science.gov (United States)

    Wadman, H. M.; Canuel, E. A.; Bauer, J. E.; McNinch, J. E.

    2009-12-01

    Small, mountainous rivers deliver a disproportionate amount of sediment and associated organic matter to coastal regions globally. The Waiapu River, North Island, New Zealand, is characterized by one of the highest sediment yields on earth, providing a model system for studying episodic delivery and preservation of sedimentary organic matter in an energetic, aggradational setting. Hyperpycnal plumes provide the primary mode of sediment delivery, depositing fine-grained sediment as flood layers on the inner shelf. Severe erosion following colonial-era (~1890-1920) slash and burn deforestation increased the sediment yield to the shelf 4- to 5-fold relative to previous levels. Colonial catchment-wide burning also produced black carbon (BC), which may be used to establish chronological control in the heterogeneous inner shelf sediments that are not easily dateable using traditional techniques. While recent work indicates that these inner shelf flood layers sequester ~16-34% of the total fine-grained sediment budget, comparable to the amount preserved on the mid-outer shelf, little is understood about the organic matter associated with these inner shelf sediments. High-resolution seismic reflection data were used to select four representative cores to characterize total sedimentary BC, total organic carbon (TOC) and total nitrogen (TN) sequestered in the inner shelf fine-grained sediments. Soot and graphitic BC (SGBC) was quantified using chemo-thermal oxidation (CTO-375), while coarse-grained BC (CGBC) was quantified using traditional point-counting methodologies. SGBC weight percentages ranged from ~0.01-0.07, and peaked at ~150cm depth in all four cores. This interval corresponds to peak abundance of CGBC as well. The ~150cm interval is interpreted to represent the height of colonial slash and burn deforestation, and is further supported by fining-upward sequences in all of the cores as well as by multiple 14C dates. Overall, SGBC represented an average of 29% (range

  17. Western Indian Ocean circulation and climate variability on different time scales. A study based on stable oxygen and carbon isotopes, benthic foraminiferal assemblages and Mg/Ca paleothermometry

    Energy Technology Data Exchange (ETDEWEB)

    Romahn, Sarah

    2014-08-19

    In order to understand the Earth's climate evolution it is crucial to evaluate the role of low-latitude oceans in the global climate system, as they are connected to both hemispheres via atmospheric and oceanic circulation and thus hold the potential to disentangle the asynchronicity of short-term Pleistocene climate variability. However, the potential of low latitude oceans to respond to and force large-scale changes of the climate system is still debated. The aim of this thesis is to examine and to understand the causal relationship of both atmospheric and oceanic changes in the tropical western Indian Ocean on centennial-, millennial and glacial-interglacial timescales. For this purpose I investigated stable oxygen and carbon isotope compositions of both planktic and benthic foraminiferal tests, Mg/Ca ratios of planktic foraminiferal tests as well as benthic foraminiferal assemblages and sedimentary geochemical parameters on two sediment cores (GeoB12615-4, 446 m and GeoB12616-4, 1449 m) from the continental slope off Tanzania, East Africa.

  18. Using 224Ra/228Th disequilibrium to quantify benthic fluxes of dissolved inorganic carbon and nutrients into the Pearl River Estuary

    Science.gov (United States)

    Cai, Pinghe; Shi, Xiangming; Hong, Qingquan; Li, Qing; Liu, Lingfeng; Guo, Xianghui; Dai, Minhan

    2015-12-01

    The 224Ra/228Th disequilibrium that was recently observed in coastal sediments has been proven to be an excellent proxy for tracing the benthic processes that regulate solute transfer across the sediment-water interface. In order to better utilize this proxy, there is a need to understand the reaction kinetics of 224Ra in sediments. In this study, depth profiles of 224Ra and 228Th in bulk sediments were collected along a transect in the Pearl River Estuary (PRE). Together with bulk sediment measurements, dissolved 224Ra, dissolved inorganic carbon (DIC), and nutrients (NO2- + NO3-, NH4+) in pore water and in the overlying waters were also determined. A marked deficit of 224Ra with respect to 228Th with large spatial variations was observed in the PRE sediments. By use of a diagenetic model for the distributions of dissolved and adsorbed 224Ra in sediments, we infer that adsorption removes 224Ra from aqueous phase at a rate of 0.1 ± 1.1-2000 ± 400 d-1. In addition, adsorption of 224Ra exhibits a rate sequence of oxic freshwater > anoxic freshwater > anoxic brackish water, probably reflecting the effect of the redox conditions and ionic strength on the adsorption-desorption kinetics of 224Ra. Benthic fluxes of 224Ra were estimated from the observed deficit of 224Ra in the sediments using a one-dimensional (1D) mass balance exchange model. We demonstrated that irrigation was the predominant process that controls solute transfer across the sediment-water interface, whereas molecular diffusion and sediment mixing together contributed <5% of the total 224Ra fluxes from bottom sediments. We then utilized the 224Ra/228Th disequilibrium approach to quantify the benthic fluxes of DIC and nutrients. We showed that sediment interstitial waters delivered approximately 42 ± 6 × 109 mol of DIC and ˜16 ± 1 × 109 mol of NH4+ into the PRE in the dry season. In contrast, it removed about 13 ± 1 × 109 mol of NO3- from the overlying water column. The benthic flux of DIC is

  19. Carbon and nitrogen uptake of calcareous benthic foraminifera along a depth-related oxygen gradient in the OMZ of the Arabian Sea

    Directory of Open Access Journals (Sweden)

    Annekatrin Julie Enge

    2016-02-01

    Full Text Available Foraminifera are an important faunal element of the benthos in oxygen-depleted settings such as Oxygen Minimum Zones (OMZs where they can play a relevant role in the processing of phytodetritus. We investigated the uptake of phytodetritus (labeled with 13C and 15N by cal-careous foraminifera in the 0-1 cm sediment horizon under different oxygen concentrations within the OMZ in the eastern Arabian Sea. The in situ tracer experiments were carried out along a depth transect on the Indian margin over a period of 4 to 10 days. The uptake of phy-todetrital carbon within 4 days by all investigated species shows that phytodetritus is a rele-vant food source for foraminifera in OMZ sediments. The decrease of total carbon uptake from 540 to 1100 m suggests a higher demand for carbon by species in the low-oxygen core region of the OMZ or less food competition with macrofauna. Especially Uvigerinids showed high uptake of phytodetrital carbon at the lowest oxygenated site. Variation in the ratio of phytodetrital carbon to nitrogen between species and sites indicates that foraminiferal carbon and nitrogen use can be decoupled and different nutritional demands are found between spe-cies. Lower ratio of phytodetrital carbon and nitrogen at 540 m could hint for greater demand or storage of food-based nitrogen, ingestion or hosting of bacteria under almost anoxic condi-tions. Shifts in the foraminiferal assemblage structure (controlled by oxygen or food availabil-ity and in the presence of other benthic organisms account for observed changes in the pro-cessing of phytodetritus in the different OMZ habitats. Foraminifera dominate the short-term processing of phytodetritus in the OMZ core but are less important in the lower OMZ bounda-ry region of the Indian margin as biological interactions and species distribution of foraminif-era change with depth and oxygen levels.

  20. Modeling Water and Carbon Budgets in Current and Future Agricultural Land Use

    Science.gov (United States)

    Drewniak, B.; Song, J.; Prell, J.; Kotamarthi, R.; Jacob, R.

    2008-12-01

    Biofuels are a key component of renewable energy mix proposed as a substitute to fossil fuels. Biofuels are suggested as both economical and having potential for reducing atmospheric emissions of carbon from the transportation sector, by building up soil carbon levels when planted on lands where these levels have been reduced by intensive tillage. The purpose of this research is to develop a carbon-nitrogen based crop module (CNC) for the community land model (CLM) and to improve the characterization of the below and above ground carbon sequestration for bioenergy crops. The CNC simulates planting, growing, maturing and harvesting stages for three major crops: maize, soybean and wheat. In addition, dynamic root module is implemented to simulate fine root distribution and development based on relative availability of soil water and nitrogen in the root zone. Coupled CLM-CNC models is used to study crop yields, geographic locations for bioenergy crop production and soil carbon changes. Bioenergy crop cultivation is based on current crop cultivation and future land use change dataset. Soil carbon change has been simulated based on carbon input to the soil from the leaf, stem and root, and carbon emission from soil carbon decomposition. Simulated water and carbon fluxes have been compared with field observations and soil carbon content has been examined under different harvest practices.

  1. Benthic macrofauna

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.; Sivadas, S.; Ingole, B.S.

    C. (2000) Environmental impact of TBT: the French experience; Science of the Total Environment 258 99?102. Alzieu C. (2006) Effects of tributyltin pollution on oyster industry: the Arcachon Bay case; In: Multiple dimensions of global environmental.... A., Ingole B. S. and Parulekar A. H. (1986) Spatial and temporal changes in benthic macrofauna from Mandovi and Zuari estuaries of Goa, west coast of India; Indian Journal of Marine Sciences 15 223?229. Ansari Z. A., Ingole B. S. and Furtado R. (2003...

  2. Estimating annual soil carbon loss in agricultural peatland soils using a nitrogen budget approach.

    Directory of Open Access Journals (Sweden)

    Emilie R Kirk

    Full Text Available Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM oxidation and physical compaction. Rice (Oryza sativa production has been proposed as an alternative cropping system to limit SOM oxidation. Preliminary research on these soils revealed high N uptake by rice in N fertilizer omission plots, which we hypothesized was the result of SOM oxidation releasing N. Testing this hypothesis, we developed a novel N budgeting approach to assess annual soil C and N loss based on plant N uptake and fallow season N mineralization. Through field experiments examining N dynamics during growing season and winter fallow periods, a complete annual N budget was developed. Soil C loss was calculated from SOM-N mineralization using the soil C:N ratio. Surface water and crop residue were negligible in the total N uptake budget (3 - 4 % combined. Shallow groundwater contributed 24 - 33 %, likely representing subsurface SOM-N mineralization. Assuming 6 and 25 kg N ha-1 from atmospheric deposition and biological N2 fixation, respectively, our results suggest 77 - 81 % of plant N uptake (129 - 149 kg N ha-1 was supplied by SOM mineralization. Considering a range of N uptake efficiency from 50 - 70 %, estimated net C loss ranged from 1149 - 2473 kg C ha-1. These findings suggest that rice systems, as currently managed, reduce the rate of C loss from organic delta soils relative to other agricultural practices.

  3. A middle Miocene benthic foraminiferal stable isotope record from extensively recrystallised carbonate sediments of IODP Site U1336 in the Equatorial Pacific

    Science.gov (United States)

    Voigt, J.; Hathorne, E. C.; Holbourn, A. E.; Frank, M.

    2013-12-01

    The elemental and isotopic composition of foraminifera is widely used for reconstructing oceanic and climatic conditions in the past. However, ancient foraminiferal tests are altered after deposition through replacement of the original biogenic calcite by secondary (inorganic) calcite. Therefore, it is important to quantify changes in the elemental and isotopic composition of recrystallised tests to assess the reliability of proxy data. Here, we present benthic foraminiferal stable isotope data from IODP Site U1336 where the geochemistry of bulk carbonates and associated pore waters suggests extensive recrystallisation resulting from an enhanced thermal gradient. In sediments older than 20.3 Ma the 87Sr/86Sr ratios of bulk carbonates and associated pore waters exhibit lower values than contemporaneous seawater indicating the incorporation of Sr originating from older carbonates recrystallised deeper in the section. Furthermore, the generally lower Sr/Ca ratios of bulk carbonates from Site U1336 also suggest extensive recrystallisation. Despite the extensive recrystallisation at Site U1336, the stable isotope composition (δ13C and δ18O) of benthic foraminifera (C. wuellerstorfi and C. mundulus) from the middle Miocene (13-16 Ma) is in good agreement with existing records (e.g. Holbourn et al. 2007, Tian et al. 2013). The carbon-isotope events of the Monterey Excursion (including CM 3b, CM 4a, CM 5 and CM 6) can clearly be identified. The CM 3b event displays the highest δ13C values with a maximum of 1.78 ‰ at 15.61 Ma which is in accordance with values measured from Sites 1237 (Nazca Ridge off Peru) and U1337 (706 km southeast from U1336) of 1.72 and 1.74 ‰, respectively at 15.60 Ma. The Middle Miocene cooling at 13.91-13.84 Ma marks the onset of ice-sheet expansion over Antarctica and the drastic increase in δ18O (0.86 ‰) at Site U1336 during that cooling event (CM 6) is comparable to that at Site 1237 (0.79 ‰) (Holbourn et al. 2007) and U1337 (1.00

  4. Is the contribution of bacteria to terrestrial carbon budget greatly underestimated?

    Science.gov (United States)

    Braissant, Olivier; Verrecchia, Eric; Aragno, Michel

    2002-07-01

    Some commonly found species of soil bacteria use low molecular weight organic acids as their sole source of carbon and energy. This study shows that acids such as citrate and oxalate (produced in large amounts by fungi and plants) can rapidly be consumed by these bacteria. Two strains, Ralstonia eutropha and Xanthobacter autotrophicus, were cultured on acetate- and citrate-rich media. The resulting CO2 and/or HCO3- reacted with calcium ions to precipitate two polymorphs of calcium carbonate (CaCO3), calcite and vaterite, depending on the quantity of slime produced by the strains. This production of primary calcium carbonate crystals by oxalate- and citrate-degrading bacteria from soil organic carbon sources highlights the existence of an important and underestimated potential carbon sink.

  5. Application of remote sensing in regional scale estimates of vegetation carbon budgets: The Belfix project

    Science.gov (United States)

    Veroustraete, Frank; Patyn, Johan; Myneni, R. B.

    1994-01-01

    A concept for coupling the remote sensing derived fraction of the absorbed photosynthetic active radiation (FAPAR) with a functional ecosystem model was developed. The study was named the Belfix procedure. The quantification of changes in carbon dynamics at the ecosystem level is a key issue in studies of global climatic change effects at the vegetation atmosphere interface. An operational procedure, for the determination of carbon fluxes at the regional scale (Belgian territory), is presented. The approach allows for the determination of the sink function of vegetation for carbon (dioxide). The phyto- and litter mass, photosynthetic assimilation, autotroph and heterotroph carbon fluxes and net ecosystem exchange (NEE) of carbon, were evaluated. The results suggest that a single solution can be obtained for ecosystem rates and states, applying an iterative procedure, based on minimizing the change in maximal seasonal green phytomass in function of yearly FAPAR temporal profiles. Total phytomass values obtained are in close range with those obtained by ground sampling.

  6. Forest carbon budgets in Southeast Asia following harvesting and land cover change

    Energy Technology Data Exchange (ETDEWEB)

    Rodel D. Lasco [University of the Philippines, Laguna (Philippines)

    2002-07-01

    Tropical forests in Southeast Asia are constantly changing as a result of harvesting and conversion to other land cover. As a result of these changes, research on C budgets of forest ecosystems has intensified in the region over the last few years. This paper reviews and synthesizes the available information. Natural forests in SE Asia typically contain a high C density (up to 500 Mg/ha). Logging activities are responsible for at least 50% decline in forest C density. Complete deforestation (conversion from forest to grassland or annual crops) results in C density of less than 40 Mg/ha. Conversion to tree plantations and other woody perennial crops also reduces C density to less than 50% of the original C forest stocks. While much information has been generated recently, there are still large gaps of information on C budgets of tropical forests and its conversion to other land uses in SE Asia. There is therefore a need to intensify research in this area.

  7. The carbon budget of terrestrial ecosystems in East Asia over the last two decades

    Directory of Open Access Journals (Sweden)

    S. Piao

    2012-03-01

    Full Text Available This REgional Carbon Cycle Assessment and Processes regional study provides a synthesis of the carbon balance of terrestrial ecosystems in East Asia, a region comprised of China, Japan, North- and South-Korea, and Mongolia. We estimate the current terrestrial carbon balance of East Asia and its driving mechanisms during 1990–2009 using three different approaches: inventories combined with satellite greenness measurements, terrestrial ecosystem carbon cycle models and atmospheric inversion models. The magnitudes of East Asia's natural carbon sink from these three approaches are comparable: −0.264 ± 0.033 Pg C yr−1 from inventory-remote sensing model-data fusion approach, −0.393 ± 0.141 Pg C yr−1 (not considering biofuel emissions or −0.204 ± 0.141 Pg C yr−1 (considering biofuel emissions for carbon cycle models, and −0.270 ± 0.507 Pg C yr−1 for atmospheric inverse models. The ensemble of ecosystem modeling based analyses further suggests that at the regional scale, climate change and rising atmospheric CO2 together resulted in a carbon sink of −0.289 ± 0.135 Pg C yr−1, while land use change and nitrogen deposition had a contribution of −0.013 ± 0.029 Pg C yr−1 and −0.107 ± 0.025 Pg C yr−1, respectively. Although the magnitude of climate change effects on the carbon balance varies among different models, all models agree that in response to climate change alone, southern China experienced an increase in carbon storage from 1990 to 2009, while northern East Asia including Mongolia and north China showed a decrease in carbon storage. Overall, our results suggest that about 13–26% of East Asia's CO2 emissions from fossil fuel burning have been offset by carbon accumulation in its terrestrial ecosystems over the period from 1990 to 2009. The underlying mechanisms of carbon sink over East Asia still remain largely

  8. Reconstructing Changes in Deep Ocean Temperature and Global Carbon Cycle during the Early Eocene Warming Trend: High-Resolution Benthic Stable Isotope Records from the SE Atlantic.

    Science.gov (United States)

    Lauretano, V.; Zachos, J. C.; Lourens, L. J.

    2014-12-01

    From the late Paleocene to the early Eocene, Earth's surface temperatures generally rose, resulting in an increase of at least 5°C in the deep ocean and culminating in the Early Eocene Climatic Optimum (EECO). This long-term warming was punctuated by a series of short-lived global warming events known as "hyperthermals", of which the Paleocene-Eocene Thermal Maximum (PETM) represents the most extreme example. At least two other short-term episodes have been identified as hyperthermals: the ETM2 (or Elmo event) at about 53.7 Myr and the ETM3 (or X-event) at about 52.5 Myr. These transient events are marked by prominent carbon isotope excursions (CIEs), recorded in marine and continental sedimentary sequences and driven by fast and massive injections of 13C-depleted carbon into the ocean-atmosphere system. Recently, evidence has indicated the presence of a regular series of hyperthermal events following the peak in temperatures of the EECO. However, continuous records are needed to investigate short- and long- term changes in the climate system throughout the Early Eocene warming trend. Here, we present new high-resolution benthic stable isotope records of the Early Eocene from ODP Site 1263, (Walvis Ridge, SE Atlantic). The carbon and oxygen records document changes in deep-sea temperature and global carbon cycle encompassing the Early Eocene hyperthermal events and the EECO interval. The transition phase to the post-EECO events is distinct by the decoupling of carbon and oxygen isotopes on the long-term scale. Spectral and wavelet analyses suggest the influence of orbital forcing, specifically long and short eccentricity cycles.

  9. Decadal changes in carbon fluxes at the East Siberian continental margin: interactions of ice cover, ocean productivity, particle sedimentation and benthic life

    Science.gov (United States)

    Boetius, A.; Bienhold, C.; Felden, J.; Fernandez Mendez, M.; Gusky, M.; Rossel, P. E.; Vedenin, A.; Wenzhoefer, F.

    2015-12-01

    The observed and predicted Climate-Carbon-Cryosphere interactions in the Arctic Ocean are likely to alter productivity and carbon fluxes of the Siberian continental margin and adjacent basins. Here, we compare field observations and samples obtained in the nineties, and recently in 2012 during the sea ice minimum, to assess decadal changes in the productivity, export and recycling of organic matter at the outer East Siberian margin. In the 90s, the Laptev Sea margin was still largely ice-covered throughout the year, and the samples and measurements obtained represent an ecological baseline against which current and future ecosystem shifts can be assessed. The POLARSTERN expedition IceArc (ARK-XXVII/3) returned in September 2012 to resample the same transects between 60 and 3400 m water depth as well as stations in the adjacent deep basins. Our results suggest that environmental changes in the past two decades, foremost sea ice thinning and retreat, have led to a substantial increase in phytodetritus sedimentation to the seafloor, especially at the lower margin and adjacent basins. This is reflected in increased benthic microbial activities, leading to higher carbon remineralization rates, especially deeper than 3000 m. Besides a relative increase in typical particle degrading bacterial types in surface sediments, bacterial community composition showed little variation between the two years, suggesting that local microbial communities can cope with changing food input. First assessments of faunal abundances suggest an increase in polychaetes,holothurians and bivalves at depth, which fits the prediction of higher productivity and particle deposition rates upon sea ice retreat. The presentation also discusses the controversial issue whether there is evidence for an Arctic-wide increase in carbon flux, or whether we are looking at a spatial shift of the productive marginal ice zone as the main factor to enhance carbon flux to the deep Siberian margin.

  10. Current and future carbon budget at Takayama site, Japan, evaluated by a regional climate model and a process-based terrestrial ecosystem model

    Science.gov (United States)

    Kuribayashi, Masatoshi; Noh, Nam-Jin; Saitoh, Taku M.; Ito, Akihiko; Wakazuki, Yasutaka; Muraoka, Hiroyuki

    2016-12-01

    Accurate projection of carbon budget in forest ecosystems under future climate and atmospheric carbon dioxide (CO2) concentration is important to evaluate the function of terrestrial ecosystems, which serve as a major sink of atmospheric CO2. In this study, we examined the effects of spatial resolution of meteorological data on the accuracies of ecosystem model simulation for canopy phenology and carbon budget such as gross primary production (GPP), ecosystem respiration (ER), and net ecosystem production (NEP) of a deciduous forest in Japan. Then, we simulated the future (around 2085) changes in canopy phenology and carbon budget of the forest by incorporating high-resolution meteorological data downscaled by a regional climate model. The ecosystem model overestimated GPP and ER when we inputted low-resolution data, which have warming biases over mountainous landscape. But, it reproduced canopy phenology and carbon budget well, when we inputted high-resolution data. Under the future climate, earlier leaf expansion and delayed leaf fall by about 10 days compared with the present state was simulated, and also, GPP, ER and NEP were estimated to increase by 25.2%, 23.7% and 35.4%, respectively. Sensitivity analysis showed that the increase of NEP in June and October would be mainly caused by rising temperature, whereas that in July and August would be largely attributable to CO2 fertilization. This study suggests that the downscaling of future climate data enable us to project more reliable carbon budget of forest ecosystem in mountainous landscape than the low-resolution simulation due to the better predictions of leaf expansion and shedding.

  11. Is the contribution of bacteria to terrestrial carbon budget greatly underestimated ?

    OpenAIRE

    Braissant, Olivier; Verrecchia, Eric P.; Aragno, Michel

    2005-01-01

    Some commonly found species of soil bacteria use low molecular weight organic acids as their sole source of carbon and energy. This study shows that acids such as citrate and oxalate (produced in large amounts by fungi and plants) can rapidly be consumed by these bacteria. Two strains, Ralstonia eutropha and Xanthobacter autotrophicus, were cultured on acetate- and citrate-rich media. The resulting CO2 and/or HCO3- reacted with calcium ions to precipitate two polymorphs of calcium carbonate (...

  12. Carbon, nitrogen, oxygen and sulfide budgets in the Black Sea : a biogeochemical model of the whole water column coupling the oxic and anoxic parts

    NARCIS (Netherlands)

    Grégoire, M.; Soetaert, K.E.R.

    2010-01-01

    Carbon, nitrogen, oxygen and sulfide budgets are derived for the Black Sea water column from a coupled physical–biogeochemical model. The model is applied in the deep part of the sea and simulates processes over the whole water column including the anoxic layer that extends from similar, equals115 m

  13. Carbon, nitrogen, oxygen and sulfide budgets in the Black Sea : a biogeochemical model of the whole water column coupling the oxic and anoxic parts

    NARCIS (Netherlands)

    Grégoire, M.; Soetaert, K.E.R.

    2010-01-01

    Carbon, nitrogen, oxygen and sulfide budgets are derived for the Black Sea water column from a coupled physical–biogeochemical model. The model is applied in the deep part of the sea and simulates processes over the whole water column including the anoxic layer that extends from similar, equals115 m

  14. The role of the coniferous forests in the carbon budget of Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Lakyda, P.; Kolosok, O.; Petrenko, M. [Forestry College, Kyiv (Ukraine). Dept. of Forest Management

    2002-10-01

    The coniferous forests of the Carpathia and Polissia regions of southern Ukraine form 37 per cent of the area and 52.9 per cent of the growing stock of all forests in Ukraine, and therefore represent a major resource. This study focused on the forests' ecological significance which is also very high and is characterized by high general forest productivity, and the magnitude of accumulation of biomass components and stored carbon. Overall state phytomass resources and accumulated carbon were calculated using an original method, modern mathematics and computerized methods of data processing. More than 300 sample plots were used to obtain a large data set stored in the State Forest Inventory electronic database. Results indicate that the overall conifer forest phytomass of Ukraine is 538 Mega tonnes (Mt) and contains more than 266 Mt of carbon. The average carbon density of the forested area of the boreal forests is 6.7 kg/m. It was noted that the use of the conversion coefficient method and multiple regression method can result in an inaccurate assessment of forest phytomass because carbon density can fluctuate depending on the tree species, forest productivity, forest age and other factors. The study also examined the trends in phytomass dynamics in both pine and spruce stands. The magnitude of their annual carbon stocks were also examined. 8 refs., 2 tabs., 2 figs.

  15. Impact of CO2 leakage from sub-seabed carbon dioxide capture and storage (CCS) reservoirs on benthic virus-prokaryote interactions and functions.

    Science.gov (United States)

    Rastelli, Eugenio; Corinaldesi, Cinzia; Dell'Anno, Antonio; Amaro, Teresa; Queirós, Ana M; Widdicombe, Stephen; Danovaro, Roberto

    2015-01-01

    Atmospheric CO2 emissions are a global concern due to their predicted impact on biodiversity, ecosystems functioning, and human life. Among the proposed mitigation strategies, CO2 capture and storage, primarily the injection of CO2 into marine deep geological formations has been suggested as a technically practical option for reducing emissions. However, concerns have been raised that possible leakage from such storage sites, and the associated elevated levels of pCO2 could locally impact the biodiversity and biogeochemical processes in the sediments above these reservoirs. Whilst a number of impact assessment studies have been conducted, no information is available on the specific responses of viruses and virus-host interactions. In the present study, we tested the impact of a simulated CO2 leakage on the benthic microbial assemblages, with specific focus on microbial activity and virus-induced prokaryotic mortality (VIPM). We found that exposure to levels of CO2 in the overlying seawater from 1,000 to 20,000 ppm for a period up to 140 days, resulted in a marked decrease in heterotrophic carbon production and organic matter degradation rates in the sediments, associated with lower rates of VIPM, and a progressive accumulation of sedimentary organic matter with increasing CO2 concentrations. These results suggest that the increase in seawater pCO2 levels that may result from CO2 leakage, can severely reduce the rates of microbial-mediated recycling of the sedimentary organic matter and viral infections, with major consequences on C cycling and nutrient regeneration, and hence on the functioning of benthic ecosystems.

  16. Constraining regional scale carbon budgets at the US West Coast using a high-resolution atmospheric inverse modeling approach

    Science.gov (United States)

    Goeckede, M.; Michalak, A. M.; Vickers, D.; Turner, D.; Law, B.

    2009-04-01

    The study presented is embedded within the NACP (North American Carbon Program) West Coast project ORCA2, which aims at determining the regional carbon balance of the US states Oregon, California and Washington. Our work specifically focuses on the effect of disturbance history and climate variability, aiming at improving our understanding of e.g. drought stress and stand age on carbon sources and sinks in complex terrain with fine-scale variability in land cover types. The ORCA2 atmospheric inverse modeling approach has been set up to capture flux variability on the regional scale at high temporal and spatial resolution. Atmospheric transport is simulated coupling the mesoscale model WRF (Weather Research and Forecast) with the STILT (Stochastic Time Inverted Lagrangian Transport) footprint model. This setup allows identifying sources and sinks that influence atmospheric observations with highly resolved mass transport fields and realistic turbulent mixing. Terrestrial biosphere carbon fluxes are simulated at spatial resolutions of up to 1km and subdaily timesteps, considering effects of ecoregion, land cover type and disturbance regime on the carbon budgets. Our approach assimilates high-precision atmospheric CO2 concentration measurements and eddy-covariance data from several sites throughout the model domain, as well as high-resolution remote sensing products (e.g. LandSat, MODIS) and interpolated surface meteorology (DayMet, SOGS, PRISM). We present top-down modeling results that have been optimized using Bayesian inversion, reflecting the information on regional scale carbon processes provided by the network of high-precision CO2 observations. We address the level of detail (e.g. spatial and temporal resolution) that can be resolved by top-down modeling on the regional scale, given the uncertainties introduced by various sources for model-data mismatch. Our results demonstrate the importance of accurate modeling of carbon-water coupling, with the

  17. Estimating rates of biologically driven coral reef framework production and erosion: a new census-based carbonate budget methodology and applications to the reefs of Bonaire

    Science.gov (United States)

    Perry, C. T.; Edinger, E. N.; Kench, P. S.; Murphy, G. N.; Smithers, S. G.; Steneck, R. S.; Mumby, P. J.

    2012-09-01

    Census-based approaches can provide important measures of the ecological processes controlling reef carbonate production states. Here, we describe a rapid, non-destructive approach to carbonate budget assessments, termed ReefBudget that is census-based and which focuses on quantifying the relative contributions made by different biological carbonate producer/eroder groups to net reef framework carbonate production. The methodology is presently designed only for Caribbean sites, but has potential to be adapted for use in other regions. Rates are calculated using data on organism cover and abundance, combined with annual extension or production rate measures. Set against this are estimates of the rates at which bioeroding species of fish, urchins and internal substrate borers erode reef framework. Resultant data provide a measure of net rates of biologically driven carbonate production (kg CaCO3 m-2 year-1). These data have potential to be integrated into ecological assessments of reef state, to aid monitoring of temporal (same-site) changes in rates of biological carbonate production and to provide insights into the key ecological drivers of reef growth or erosion as a function of environmental change. Individual aspects of the budget methodology can also be used alongside other census approaches if deemed appropriate for specific study aims. Furthermore, the methodology spreadsheets are user-changeable, allowing local or new process/rate data to be integrated into calculations. Application of the methodology is considered at sites around Bonaire. Highest net rates of carbonate production, +9.52 to +2.30 kg CaCO3 m-2 year-1, were calculated at leeward sites, whilst lower rates, +0.98 to -0.98 kg CaCO3 m-2 year-1, were calculated at windward sites. Data are within the ranges calculated in previous budget studies and provide confidence in the production estimates the methodology generates.

  18. Seeking potential contributions to future carbon budget in conterminous US forests considering disturbances

    Science.gov (United States)

    Zhang, Fangmin; Pan, Yude; Birdsey, Richard A.; Chen, Jing M.; Dugan, Alexa

    2016-09-01

    Currently, US forests constitute a large carbon sink, comprising about 9 % of the global terrestrial carbon sink. Wildfire is the most significant disturbance influencing carbon dynamics in US forests. Our objective is to estimate impacts of climate change, CO2 concentration, and nitrogen deposition on the future net biome productivity (NBP) of US forests until the end of twenty-first century under a range of disturbance conditions. We designate three forest disturbance scenarios under one future climate scenario to evaluate factor impacts for the future period (2011-2100): (1) no wildfires occur but forests continue to age (Saging), (2) no wildfires occur and forest ages are fixed in 2010 (Sfixed_nodis), and (3) wildfires occur according to a historical pattern, consequently changing forest age (Sdis_age_change). Results indicate that US forests remain a large carbon sink in the late twenty-first century under the Sfixed_nodis scenario; however, they become a carbon source under the Saging and Sdis_age_change scenarios. During the period of 2011 to 2100, climate is projected to have a small direct effect on NBP, while atmospheric CO2 concentration and nitrogen deposition have large positive effects on NBP regardless of the future climate and disturbance scenarios. Meanwhile, responses to past disturbances under the Sfixed_nodis scenario increase NBP regardless of the future climate scenarios. Although disturbance effects on NBP under the Saging and Sdis_age_change scenarios decrease with time, both scenarios experience an increase in NBP prior to the 2050s and then a decrease in NBP until the end of the twenty-first century. This study indicates that there is potential to increase or at least maintain the carbon sink of conterminous US forests at the current level if future wildfires are reduced and age structures are maintained at a productive mix. The effects of CO2 on the future carbon sink may overwhelm effects of other factors at the end of the twenty

  19. Introducing non-flooded crops in rice-dominated landscapes: Impact on carbon, nitrogen and water budgets

    Science.gov (United States)

    Jauker, Frank; Wassmann, Reiner; Amelung, Wulf; Breuer, Lutz; Butterbach-Bahl, Klaus; Conrad, Ralf; Ekschmitt, Klemens; Goldbach, Heiner; He, Yao; John, Katharina; Kiese, Ralf; Kraus, David; Reinhold-Hurek, Barbara; Siemens, Jan; Weller, Sebastian; Wolters, Volkmar

    2013-04-01

    Rice production consumes about 30% of all freshwater used worldwide and 45% in Asia. Turning away from permanently flooded rice cropping systems for mitigating future water scarcity and reducing methane emissions, however, will alter a variety of ecosystem services with potential adverse effects to both the environment and agricultural production. Moreover, implementing systems that alternate between flooded and non-flooded crops increases the risk of disruptive effects. The multi-disciplinary DFG research unit ICON aims at exploring and quantifying the ecological consequences of altered water regimes (flooded vs. non-flooded), crop diversification (irrigated rice vs. aerobic rice vs. maize), and different fertilization strategies (conventional, site-specific, and zero N fertilization). ICON particularly focuses on the biogeochemical cycling of carbon and nitrogen, green-house gas (GHG) emissions, water balance, soil biotic processes and other important ecosystem services. The overarching goal is to provide the basic process understanding that is necessary for balancing the revenues and environmental impacts of high-yield rice cropping systems while maintaining their vital ecosystem services. To this aim, a large-scale field experiment has been established at the experimental farm of the International Rice Research Institute (IRRI, Philippines). Ultimately, the experimental results are analyzed in the context of management scenarios by an integrated modeling of crop development (ORYZA), carbon and nitrogen cycling (MoBiLE-DNDC), and water fluxes (CMF), providing the basis for developing pathways to a conversion of rice-based systems towards higher yield potentials under minimized environmental impacts. In our presentation, we demonstrate the set-up of the controlled large-scale field experiment for simultaneous assessment of carbon and nitrogen fluxes and water budgets. We show and discuss first results for: - Quantification and assessment of the net-fluxes of CH4

  20. Audit of the global carbon budget: estimate errors and their impact on uptake uncertainty

    Science.gov (United States)

    Ballantyne, A. P.; Andres, R.; Houghton, R.; Stocker, B. D.; Wanninkhof, R.; Anderegg, W.; Cooper, L. A.; DeGrandpre, M.; Tans, P. P.; Miller, J. C.; Alden, C.; White, J. W. C.

    2014-10-01

    Over the last 5 decades monitoring systems have been developed to detect changes in the accumulation of C in the atmosphere, ocean, and land; however, our ability to detect changes in the behavior of the global C cycle is still hindered by measurement and estimate errors. Here we present a rigorous and flexible framework for assessing the temporal and spatial components of estimate error and their impact on uncertainty in net C uptake by the biosphere. We present a novel approach for incorporating temporally correlated random error into the error structure of emission estimates. Based on this approach, we conclude that the 2 σ error of the atmospheric growth rate has decreased from 1.2 Pg C yr-1 in the 1960s to 0.3 Pg C yr-1 in the 2000s, leading to a ~20% reduction in the over-all uncertainty of net global C uptake by the biosphere. While fossil fuel emissions have increased by a factor of 4 over the last 5 decades, 2 σ errors in fossil fuel emissions due to national reporting errors and differences in energy reporting practices have increased from 0.3 Pg C yr-1 in the 1960s to almost 1.0 Pg C yr-1 during the 2000s. At the same time land use emissions have declined slightly over the last 5 decades, but their relative errors remain high. Notably, errors associated with fossil fuel emissions have come to dominate uncertainty in the global C budget and are now comparable to the total emissions from land use, thus efforts to reduce errors in fossil fuel emissions are necessary. Given all the major sources of error in the global C budget that we could identify, we are 93% confident that C uptake has increased and 97% confident that C uptake by the terrestrial biosphere has increased over the last 5 decades. Although the persistence of future C sinks remains unknown and some ecosystem services may be compromised by this continued C uptake (e.g. ocean acidification), it is clear that arguably the greatest ecosystem service currently provided by the biosphere is the

  1. Seasonal variations in carbon budget in water column off Princess Astrid coast, Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V.K.; Matondkar, S.G.P.; Verlecar, X.N.

    summer (600 to 2255 no. 100 m sup(-3)) and low in winter (437 to 1184 no. 100 m sup(-3)). Particulate carbon values ranged from 46 to 83 mu g l sup(-1) during summer and from 22.2 to 63.8 mu g l sup(-1) in winter. Particulate nitrogen showed little...

  2. Equity and the Allocation of Miigation Burdens: A Carbon Budgets Approach

    Science.gov (United States)

    Kanitkar, T. T. I. O. S. S.

    2014-12-01

    The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5) provides global estimates of future cumulative carbon dioxide emissions of anthropogenic origin, for various representative concentration pathways (RCP). For example, for an approximately 50% probability of limiting the increase in temperature to 2 deg. C, the table shows that the limit on cumulative global carbon-dioxide emissions is 780 Gt of carbon between 2012 and 2100. We can now ask what each nation will get as a share of the globally allowed cumulative emissions. Corresponding to this share of cumulative emissions, every nation will have the flexibility to consider a range of emissions trajectories within its share. This paper calculates the "entitlements" and potential emissions (based on some reasonable growth and reduction rates) using four different methods for all the four RCPs discussed in the IPCC report - i) simply allocating the remaining carbon space (for the period from 2012 to 2100) on a per capita basis amongst the regions; ii) calculating entitlements for the period between 1850 and 2100 based on total emissions emitted in the past and allowed in the future divided among countries on a per capita basis; iii) the entitlements calculated in (ii) are weighted by per capita GDP to include a measure of 'capability' while calculating entitlements; iv) the entitlements calculated in (ii) are weighted by non-income HDI as another measure of 'capability'. The values are benchmarked against the potential emissions for the future resulting from the commitments already made by different countries and regions towards mitigation. The paper then goes on to provide an estimate for the avoided cost of carbon for India given a range of constraints on emissions that it will have to undertake as a part of such a schema of allocating the mitigation burden.

  3. How does wind-throw disturbance affect the carbon budget of an upland spruce forest ecosystem?

    Science.gov (United States)

    Lindauer, Matthias; Schmid, Hans Peter; Grote, Rüdiger; Mauder, Matthias; Wolpert, Benjamin; Steinbrecher, Rainer

    2014-05-01

    Forests, especially in mid-latitudes are generally designated as large carbon sinks. However, stand-replacing disturbance events like fires, insect-infestations, or severe wind-storms can shift an ecosystem from carbon sink to carbon source within short time and keep it as this for a long time. In Addition, extreme weather situations which promote the occurrence of ecosystem disturbances are likely to increase in the future due to climate change. The development and competition of different vegetation types (spruce vs. grass) as well as soil organic matter (SOM), and their contribution to the net ecosystem exchange (NEE), in such disturbed forest ecosystems are largely unknown. In a large wind-throw area (ca. 600 m diameter, due to cyclone Kyrill in January 2007) within a mature upland spruce forest, where dead-wood has not been removed, in the Bavarian Forest National Park (Lackenberg, 1308 m a.s.l., Bavaria, Germany), fluxes of CO2, water vapor and energy have been measured with the Eddy Covariance (EC) method since 2009. Model simulations (MoBiLE) were used to estimate the GPP components from trees and grassland as well as to differentiate between soil and plant respiration, and to get an idea about the long term behavior of the ecosystems carbon exchange. For 2009, 2010, 2011, 2012, and 2013 estimates of annual Net Ecosystem Exchange (NEE) showed that the wind-throw was a marked carbon source. However, the few remaining trees and newly emerging vegetation (grass, sparse young spruce, etc.) lead to an already strong Gross Ecosystem Production (GEP). Model simulations conformed well with the measurements. To our knowledge, we present the worldwide first long-term measurements of NEE within a non-cleared wind-throw-disturbed forest ecosystem.

  4. Carbon isotope excursions and the oxidant budget of the Ediacaran atmosphere and ocean

    Science.gov (United States)

    Bristow, Thomas F.; Kennedy, Martin J.

    2008-11-01

    A possible global drop in marine carbon isotope values to aslow as -12 Peedee belemnite (PDB), recorded in the EdiacaranShuram Formation of Oman, has been attributed to the non-steady-stateoxidation of oceanic dissolved organic carbon (DOC) resultingfrom the rise in atmospheric oxygen to near modern values atthe end of the Precambrian. Geologic constraints indicate thatthe excursion lasted between 25 and 50 m.y., requiring a DOCpool thousands of times to 10,000 times the modern inventoryto conform with carbon isotope mass balance calculations fora -12 excursion. At the consequent rates of DOC oxidation,oceanic sulfate and oxygen in the atmosphere and oceans areexhausted on a time scale of 800 k.y. Oxidant depletion isincompatible with independent geochemical and biological indicatorsthat show oceanic sulfate and oxygen levels were maintainedor increased during the Shuram excursion. Furthermore, a DOC-drivenexcursion does not explain strong covariation between the carbonand oxygen isotope record. These indicators show that negativeisotope excursions recorded in the Shuram and other Ediacaransections are unlikely to represent a global ocean signal.

  5. Historical analysis and modeling of the forest carbon dynamics using the Carbon Budget Model: an example for the Trento Province (NE, Italy

    Directory of Open Access Journals (Sweden)

    Pilli R

    2014-02-01

    Full Text Available Historical analysis and modeling of the forest carbon dynamics using the Carbon Budget Model: an example for the Trento Province (NE, Italy. The Carbon Budget Model (CBM-CFS3 developed by the Canadian Forest Service was applied to data collected by the last Italian National Forest Inventory (INFC for the Trento Province (NE, Italy. CBM was modified and adapted to the different management types (i.e., even-aged high forests, uneven-aged high forests and coppices and silvicultural systems (including clear cuts, single tree selection systems and thinning applied in this province. The aim of this study was to provide an example of down-scaling of this model from a national to a regional scale, providing (i an historical analysis, from 1995 to 2011, and (ii a projection, from 2012 to 2020, of the forest biomass and the carbon stock evolution. The analysis was based on the harvest rate reported by the Italian National Institute of Statistics (from 1995 to 2011, corrected according to the last INFC data and distinguished between timber and fuel woods and between conifers and broadleaves. Since 2012, we applied a constant harvest rate, equal to about 1300 Mm3 yr-1, estimated from the average harvest rate for the period 2006-2011. Model results were consistent with similar data reported in the literature. The average biomass C stock was 90 Mg C ha-1 and the biomass C stock change was 0.97 Mg C ha-1 yr-1 and 0.87 Mg C ha-1 yr-1, for the period 1995 -2011 and 2012-2020, respectively. The C stock cumulated by the timber products since 1995 was 96 Gg C yr-1, i.e., about 28% of the average annual C stock change of the forests, equal to 345 Gg C yr-1. CBM also provided estimates on the evolution of the age class distribution of the even-aged forests and on the C stock of the DOM forest pools (litter, dead wood and soil. This study demonstrates the utility of CBM to provide estimates at a regional or local scale, using not only the data provided by the forest

  6. Global atmospheric carbon budget: results from an ensemble of atmospheric CO2 inversions

    Directory of Open Access Journals (Sweden)

    P. Peylin

    2013-03-01

    Full Text Available Atmospheric CO2 inversions estimate surface carbon fluxes from an optimal fit to atmospheric CO2 measurements, usually including prior constraints on the flux estimates. Eleven sets of carbon flux estimates are compared, generated by different inversions systems that vary in their inversions methods, choice of atmospheric data, transport model and prior information. The inversions were run for at least 5 yr in the period between 1990 and 2009. Mean fluxes for 2001–2004, seasonal cycles, interannual variability and trends are compared for the tropics and northern and southern extra-tropics, and separately for land and ocean. Some continental/basin-scale subdivisions are also considered where the atmospheric network is denser. Four-year mean fluxes are reasonably consistent across inversions at global/latitudinal scale, with a large total (land plus ocean carbon uptake in the north (−3.3 Pg Cy−1 (±0.6 standard deviation nearly equally spread between land and ocean, a significant although more variable source over the tropics (1.6 ± 1.0 Pg Cy−1 and a compensatory sink of similar magnitude in the south (−1.4 ± 0.6 Pg Cy−1 corresponding mainly to an ocean sink. Largest differences across inversions occur in the balance between tropical land sources and southern land sinks. Interannual variability (IAV in carbon fluxes is larger for land than ocean regions (standard deviation around 1.05 versus 0.34 Pg Cy−1 for the 1996–2007 period, with much higher consistency amoung the inversions for the land. While the tropical land explains most of the IAV (stdev ∼ 0.69 Pg Cy−1, the northern and southern land also contribute (stdev ∼ 0.39 Pg Cy−1. Most inversions tend to indicate an increase of the northern land carbon uptake through the 2000s (around 0.11 Pg Cy−1, shared by North America and North Asia. The mean seasonal cycle appears to be well constrained by the atmospheric data over the northern land (at the continental scale, but

  7. Global atmospheric carbon budget: results from an ensemble of atmospheric CO2 inversions

    Directory of Open Access Journals (Sweden)

    P. Peylin

    2013-10-01

    Full Text Available Atmospheric CO2 inversions estimate surface carbon fluxes from an optimal fit to atmospheric CO2 measurements, usually including prior constraints on the flux estimates. Eleven sets of carbon flux estimates are compared, generated by different inversions systems that vary in their inversions methods, choice of atmospheric data, transport model and prior information. The inversions were run for at least 5 yr in the period between 1990 and 2010. Mean fluxes for 2001–2004, seasonal cycles, interannual variability and trends are compared for the tropics and northern and southern extra-tropics, and separately for land and ocean. Some continental/basin-scale subdivisions are also considered where the atmospheric network is denser. Four-year mean fluxes are reasonably consistent across inversions at global/latitudinal scale, with a large total (land plus ocean carbon uptake in the north (−3.4 Pg C yr−1 (±0.5 Pg C yr−1 standard deviation, with slightly more uptake over land than over ocean, a significant although more variable source over the tropics (1.6 ± 0.9 Pg C yr−1 and a compensatory sink of similar magnitude in the south (−1.4 ± 0.5 Pg C yr−1 corresponding mainly to an ocean sink. Largest differences across inversions occur in the balance between tropical land sources and southern land sinks. Interannual variability (IAV in carbon fluxes is larger for land than ocean regions (standard deviation around 1.06 versus 0.33 Pg C yr−1 for the 1996–2007 period, with much higher consistency among the inversions for the land. While the tropical land explains most of the IAV (standard deviation ~ 0.65 Pg C yr−1, the northern and southern land also contribute (standard deviation ~ 0.39 Pg C yr−1. Most inversions tend to indicate an increase of the northern land carbon uptake from late 1990s to 2008 (around 0.1 Pg C yr−1, predominantly in North Asia. The mean seasonal cycle appears to be well constrained by the atmospheric data over

  8. Forest transitions in Eastern Europe and their effects on carbon budgets

    DEFF Research Database (Denmark)

    Kuemmerle, Tobias; Kaplan, Jed O.; Prishchepov, Alexander

    2015-01-01

    area, we homogenized statistics at the provincial level for ad 1700-2010 to identify forest transition years and forest trends. We contrast our reconstruction with the KK11 and HYDE 3.1 land change scenarios, and use all three datasets to drive the LPJ dynamic global vegetation model to calculate...... or continuously declining forest area. Our data suggest extensive deforestation in European Russia already prior to ad 1700, and even greater deforestation in the 18th and 19th centuries than in the KK11 and HYDE scenarios. Based on our reconstruction, cumulative carbon emissions from deforestation were greater...

  9. Coastal Benthic Boundary Layer (CBBL) Research Program

    Science.gov (United States)

    1998-09-01

    Ecologic Atlas of Benthic Foraminifera of the Gulf of Mexico . Marine Science International, Woods Hole, MA, 174 p. Shiller, Alan, M., Brunner, Charlotte A...implications for the preservation of skeletal carbonates. Sedimentology, 45:39-51. Poag, C. Wylie, 1981. Ecologic Atlas of Benthic Foraminifera of the Gulf of...of the inner continental shelf. The shelf of the northeastern Gulf of Mexico is currently sediment-starved with most material deposited by the

  10. Carbon fluxes and the carbon budget in agroecosystems on agro-gray soils of the forest-steppe in the Baikal region

    Science.gov (United States)

    Pomazkina, L. V.; Sokolova, L. G.; Zvyagintseva, E. N.

    2013-06-01

    Field studies devoted to the transformation of the carbon cycle in agroecosystems on agro-gray soils (including soils contaminated with fluorides from aluminum smelters) in dependence on the changes in the hydrothermic conditions were performed for the first time within the framework of the long-term (1996-2010) soil monitoring in the forest-steppe zone of the Baikal region. The major attention was paid to the impact of the environmental factors on the synthesis and microbial destruction of organic carbon compounds. Certain differences in the fluxes and budget of carbon were found for the plots with cereal and row crops and for the permanent and annual fallow plots. The adverse effect of fluorides manifested itself in the enhanced C-CO2 emission under unfavorable water and temperature conditions. The long-term average C-CO2 emission from the soils contaminated with fluorides in agroecosystems with wheat after fallow was higher than that from the uncontaminated soil (179 and 198 g of C/m2, respectively) and higher than that in the agroecosystems with a potato monoculture (129 and 141 g of C/m2, respectively). At the same time, no significant variations in the content of the carbon of the microbial biomass (Cmicr) in dependence on the environmental factors were found. The utilization of carbon for respiration and for growth of the soil microorganisms on the contaminated soil were unbalanced in particular years and for the entire period of the observations. The ratio between the fluxes of the net mineralized and re-immobilized carbon was used for the integral assessment of the functioning regime of the agroecosystems and the loads on them. Independently from the soil contamination with fluorides, the loads on the agroecosystems with wheat were close to the maximum permissible value, and the loads on the agroecosystems with potatoes were permissible. It was shown that the carbon deficit in the uncontaminated soils was similar under the wheat and potatoes (-30 and -28 g

  11. Carbon budgets of biological soil crusts at micro-, meso-, and global scales

    Science.gov (United States)

    Sancho, Leopoldo G; Belnap, Jayne; Colesie, Claudia; Raggio, Jose; Weber, Bettina

    2016-01-01

    The importance of biocrusts in the ecology of arid lands across all continents is widely recognized. In spite of this broad distribution, contributions of biocrusts to the global biogeochemical cycles have only recently been considered. While these studies opened a new view on the global role of biocrusts, they also clearly revealed the lack of data for many habitats and of overall standards for measurements and analysis. In order to understand carbon cycling in biocrusts and the progress which has been made during the last 15 years, we offer a multi-scale approach covering different climatic regions. We also include a discussion on available measurement techniques at each scale: A micro-scale section focuses on the individual organism level, including modeling based on the combination of field and lab data. The meso-scale section addresses the CO2 exchange of a complete ecosystem or at the community level. Finally, we consider the contribution of biocrusts at a global scale, giving a general perspective of the most relevant findings regarding the role of biological soil crusts in the global terrestrial carbon cycle.

  12. Mammals in the areas adjacent to Forsmark and Oskarshamn. Population density, ecological data and carbon budget

    Energy Technology Data Exchange (ETDEWEB)

    Truve, Johan; Cederlund, Goeran [Svensk Naturfoervaltning AB, Ramsberg (Sweden)

    2005-06-01

    The Swedish Nuclear Fuel and Waste Management Co is in the process of selecting a safe and environmentally acceptable location for the deep-level repository of radioactive waste. SKB has expressed the importance of monitoring mammal species that are of interest both in biodiversity issues and for local hunting and recreational purposes. Two of the major goals are to: 1) monitor dynamics of population density over several years; 2) obtain information that is essential for modelling of energy/carbon flows in the biosphere and ultimately calculations of the risks of exposure to radionuclides. This report contributes to the major goals by presenting: Results from surveys of mammal abundance in the study sites near Forsmark and Oskarshamn, and a comparison with data from other surveys. A summary of traits associated to demography, resource selection and spatial distribution. A model framework that can be used to model the future development of populations. A plausible future scenario for mammal species. Mammal contribution to fluxes of energy and material in the ecosystem. Estimated harvest rates of mammals in the study sites. General conclusions that can be drawn from the survey are that population densities of the most common species are in the same range as many other populations. Lynx, wild boar, red deer and fallow deer are expanding in the areas. Marine mammals have not been surveyed but at least grey seals are important top consumers in the coastal ecosystem. Red listed species resident in the areas are Lynx, Otter, Whiskered bat, Natterer's bat, Nathusius' pipistrelle and Harbour seal. Annual production of the mammal species that were surveyed was 40-50 mg carbon/m2 and year. Hunters harvest nearly half of the production each year. Future developments for the populations are briefly discussed and a model framework that can be used to make better quantitative predictions is presented.

  13. Quantifying the erosion effect on current carbon budget of European agricultural soils at high spatial resolution.

    Science.gov (United States)

    Lugato, Emanuele; Paustian, Keith; Panagos, Panos; Jones, Arwyn; Borrelli, Pasquale

    2016-05-01

    The idea of offsetting anthropogenic CO2 emissions by increasing global soil organic carbon (SOC), as recently proposed by French authorities ahead of COP21 in the 'four per mil' initiative, is notable. However, a high uncertainty still exits on land C balance components. In particular, the role of erosion in the global C cycle is not totally disentangled, leading to disagreement whether this process induces lands to be a source or sink of CO2. To investigate this issue, we coupled soil erosion into a biogeochemistry model, running at 1 km(2) resolution across the agricultural soils of the European Union (EU). Based on data-driven assumptions, the simulation took into account also soil deposition within grid cells and the potential C export to riverine systems, in a way to be conservative in a mass balance. We estimated that 143 of 187 Mha have C erosion rates 0.45 Mg C ha(-1) yr(-1). In comparison with a baseline without erosion, the model suggested an erosion-induced sink of atmospheric C consistent with previous empirical-based studies. Integrating all C fluxes for the EU agricultural soils, we estimated a net C loss or gain of -2.28 and +0.79 Tg yr(-1) of CO2 eq, respectively, depending on the value for the short-term enhancement of soil C mineralization due to soil disruption and displacement/transport with erosion. We concluded that erosion fluxes were in the same order of current carbon gains from improved management. Even if erosion could potentially induce a sink for atmospheric CO2, strong agricultural policies are needed to prevent or reduce soil erosion, in order to maintain soil health and productivity.

  14. Isotopically constrained soil carbon and nitrogen budgets in a soybean field chronosequence in the Brazilian Amazon region

    Science.gov (United States)

    Figueira, Adelaine M. e. Silva; Davidson, Eric A.; Nagy, R. Chelsea; Riskin, Shelby H.; Martinelli, Luiz A.

    2016-10-01

    The impacts of large-scale conversion of cattle pastures to cropland on soil carbon (C) and nitrogen (N) stocks are poorly understood in the Amazon region. The objective of this research was to determine whether soybean cultivation on a previously deforested and pastured soil has changed C and N stocks and dynamics. We sampled a chronosequence of soybean fields in 2009 and again in 2013. We hypothesized that detecting statistically significant changes in total soil C and N stocks would be difficult but that fluxes of C and N through the soil would be sufficiently large to significantly decrease the stable isotope ratios of soil organic matter. We observed statistically significant decreases in the 13C and 15N enrichments and C:N ratio. When combined with estimates of crop biomass production, harvest yield, and biological nitrogen fixation, these measurements provided sufficient constraints for C and N budgets to infer modest rates of net change in soil N (+15 to +27 kg N ha-1 yr-1) and soil C (-0.15 to -0.30 Mg C ha-1 yr-1) in the top 10 cm of soil. These results indicate that this intensive soybean cropping system is having minimal impacts on N loss to the environment but likely is a small net source of C to the atmosphere.

  15. Sink or link? The bacterial role in benthic carbon cycling in the Arabian Sea’s oxygen minimum zone

    NARCIS (Netherlands)

    Pozzato, L.; van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J.J.

    2013-01-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isot

  16. Sink or link? The bacterial role in benthic carbon cycling in the Arabian Sea's oxygen minimum zone

    NARCIS (Netherlands)

    Pozzato, L.; van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J.J

    2013-01-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isot

  17. Sink or link? The bacterial role in benthic carbon cycling in the Arabian Sea's oxygen minimum zone

    NARCIS (Netherlands)

    Pozzato, L.; van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J.J

    2013-01-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isot

  18. Sink or link? The bacterial role in benthic carbon cycling in the Arabian Sea’s oxygen minimum zone

    NARCIS (Netherlands)

    Pozzato, L.; van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J.J.

    2013-01-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isot

  19. Late Budgets

    DEFF Research Database (Denmark)

    Andersen, Asger Lau; Lassen, David Dreyer; Nielsen, Lasse Holbøll Westh

    The budget forms the legal basis of government spending. If a budget is not in place at the beginning of the fiscal year, planning as well as current spending are jeopardized and government shutdown may result. This paper develops a continuous-time war-of-attrition model of budgeting...... in a presidential style-democracy to explain the duration of budget negotiations. We build our model around budget baselines as reference points for loss averse negotiators. We derive three testable hypotheses: there are more late budgets, and they are more late, when fiscal circumstances change; when such changes...... are negative rather than positive; and when there is divided government. We test the hypotheses of the model using a unique data set of late budgets for US state governments, based on dates of budget approval collected from news reports and a survey of state budget o¢ cers for the period 1988...

  20. Late Budgets

    DEFF Research Database (Denmark)

    Andersen, Asger Lau; Lassen, David Dreyer; Nielsen, Lasse Holbøll Westh

    are negative rather than positive; and when there is divided government. We test the hypotheses of the model using a unique data set of late budgets for US state governments, based on dates of budget approval collected from news reports and a survey of state budget o¢ cers for the period 1988......The budget forms the legal basis of government spending. If a budget is not in place at the beginning of the fiscal year, planning as well as current spending are jeopardized and government shutdown may result. This paper develops a continuous-time war-of-attrition model of budgeting...... in a presidential style-democracy to explain the duration of budget negotiations. We build our model around budget baselines as reference points for loss averse negotiators. We derive three testable hypotheses: there are more late budgets, and they are more late, when fiscal circumstances change; when such changes...

  1. Sink or link? The bacterial role in benthic carbon cycling in the Arabian sea oxygen minimum zone

    Science.gov (United States)

    Pozzato, L.; Van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J. J.

    2013-06-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic aquatic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea Oxygen Minimum Zone (OMZ) to study the importance of the microbial loop in this setting. Particulate organic matter, added as phytodetritus, was processed by bacteria, protozoa and metazoans, while dissolved organic matter was processed only by bacteria and there was very little, if any, transfer to higher trophic levels within the experimental period. This lack of significant transfer of bacterial-derived carbon to metazoan consumers indicates that the bacterial loop is rather inefficient in these sediments. Moreover, metazoans directly consume labile particulate organic matter resources and thus compete with bacteria for phytodetritus.

  2. Sink or link? The bacterial role in benthic carbon cycling in the Arabian sea oxygen minimum zone

    Directory of Open Access Journals (Sweden)

    L. Pozzato

    2013-06-01

    Full Text Available The bacterial loop, the consumption of dissolved organic matter (DOM by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic aquatic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea Oxygen Minimum Zone (OMZ to study the importance of the microbial loop in this setting. Particulate organic matter, added as phytodetritus, was processed by bacteria, protozoa and metazoans, while dissolved organic matter was processed only by bacteria and there was very little, if any, transfer to higher trophic levels within the experimental period. This lack of significant transfer of bacterial-derived carbon to metazoan consumers indicates that the bacterial loop is rather inefficient in these sediments. Moreover, metazoans directly consume labile particulate organic matter resources and thus compete with bacteria for phytodetritus.

  3. Sink or link? The bacterial role in benthic carbon cycling in the Arabian sea oxygen minimum zone

    OpenAIRE

    Pozzato, L.; van Oevelen, D.; Moodley, L; Soetaert, K.; Middelburg, J. J.

    2013-01-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic aquatic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea Oxygen Minimum Zone (OMZ) to study the importance of the microbial loop...

  4. A Multi-Model Comparison of Black Carbon Budgets in the Arctic Region.

    Science.gov (United States)

    Mahmood, R.; von Salzen, K.; Flanner, M.; Sand, M.; Langner, J.; Wang, H.; Huang, L.

    2015-12-01

    In this study we quantify modeled aerosol processes related to black carbon (BC) concentrations in the Arctic region in several general circulation models used by the Expert Group on Arctic Monitoring and Assessment Program (AMAP). All models simulated well the observed seasonal cycle of BC concentrations in the high Canadian Arctic region, however, most models (except CanAM) underestimate the total concentrations. Transport of BC from lower latitudes is the major source for the Arctic region where emissions are small. The models produce similar seasonal cycle of BC transport towards the Arctic with maximum transport in July. However, substantial differences were found among the models in simulating BC burdens and vertical distributions with some models producing very week seasonal cycle while others producing stronger seasonality. The annual mean BC residence times in models also differs markedly with CanAM having the shortest residence times followed by SMHI-MATCH, CESM and NorESM. There are substantial differences among the models in simulating the relative role of wet and dry deposition rates which is one of the major factors causing variations in the seasonality of BC burdens in the models. Similarly, significant differences in wet deposition efficiencies among the models exist and are the leading cause of differences in simulated BC burdens. To further explore these processes, we performed several sensitivity tests in CanAM and CESM. Overall, the results indicate that scavenging of BC in convective clouds as compared to simulations without convective BC scavenging substantially increases the overall efficiency of BC wet deposition which leads to low BC burdens and a more pronounced seasonal cycle.

  5. The influence of oceanographic processes on pelagic-benthic coupling in polar regions: A benthic perspective

    Science.gov (United States)

    Grebmeier, Jacqueline M.; Barry, James P.

    1991-08-01

    Benthic community abundance and biomass in polar marine systems is directly influenced by food supply from the overlying water column. Variability in hydrographic regimes, ice coverage, light, water column temperature and pelagic food web structure limit the amount of organic carbon reaching the benthos. Data from the high Arctic and Antarctic indicate that a large percentage of surface-produced organic matter is consumed by both macro- and micro-zooplankton as well as recycled in the water column via the microbial loop. This results in food-limited regimes for the underlying benthos. The few exceptions are nearshore continental shelf systems, such as in the Bering and Chukchi Seas in the western Arctic and portions of the Canadian Archipelago and Barents Sea in the eastern Arctic, where high benthic abundance and biomass occurs due to a tight coupling between water column primary production and benthic secondary production. A major difference between the Antarctic and Arctic is that the nearshore deep Antarctic is characterized by relatively high benthic abundance and biomass despite low water column production, suggesting that stability, low disturbance levels and cold temperatures enable benthic organisms to grow larger than in the Arctic. Both physical and biological disturbance levels are high in the marginal seas of the Arctic may directly influence benthic productivity. The relationship between primary production and sedimentation of organic material to the benthos is nonlinear due to its dependence on the role of the pelagic food web. Therefore, in this review we will only discuss the pelagic system with respect to how it impacts the net food supply reachig the benthos. A major objective of this review paper is demonstrate the influence of oceanographic processes on pelagic-benthic coupling in polar regions from a "bottom-up" perspective, using benthic studies from various regions in both the Arctic and Antarctic. Similarities and differences in

  6. Carbon budgets for catchments across a managed landscape mosaic in southeast Sweden: contributing to the safety assessment of a nuclear waste repository.

    Science.gov (United States)

    Löfgren, Anders; Miliander, Sofia; Truvé, Johan; Lindborg, Tobias

    2006-12-01

    Ecosystem budgets of matter contribute to the assessment of transport and accumulation of bioavailable contaminants in a landscape, since flows of matter and energy ultimately determine the rates at which contaminants will be partitioned in the environment. This study compares ecosystem properties, such as net primary production (NPP), sequestration of matter and fluxes to food sources for humans, which are of potential interest to describe fluxes and accumulation of bioavailable radionuclides in 14 catchments within a larger catchment area in southeast Sweden. The carbon budgets, used as a proxy for organic matter, are mainly based on local estimates of pools and fluxes, which have been distributed across a landscape mosaic of different vegetation types and management regimes using a geographical information system (GIS). NPP varied by a factor close to two (432 - 709 g x Cx m(-2)x y(-1)), while net ecosystem production ranged between -124 and 159 gx C x m(-2) x y (-1) for the different catchments. Carbon sequestration mainly occurred in the vegetation while the soil organic carbon pool was mainly a source of carbon. Large herbivores consumed on average 4.5 % of the above-ground green tissue production. When arable land was present in the catchment, the flux of carbon to humans was highest from crops and, in decreasing order, milk and beef, followed by the flux from hunting and berry/fungus picking. The results can be used to estimate the potential assimilation of radionuclides in vegetation and the potential exposure to humans of bioavailable radionuclides.

  7. Land Use and Changes in Carbon Budget in the Brazilian Cerrado

    Science.gov (United States)

    Bustamante, M.; Potter, C.; Corbeels, M.; Scopel, E.

    2007-12-01

    Tropical savannas cover 22.5 x 106 km2, an area nearly 30% larger than the area of tropical forests. Although the average carbon \\(C\\) content of savanna vegetation is only about 25% as great as tropical forest vegetation (29 vs. 120 Mg C ha-1), land use changes in tropical savannas are even more rapid than changes in tropical forests. The Brazilian savanna, locally known as Cerrado, covers about 2 x 106 km2 and is the largest savanna formation in South America. Its area is comparable to the Miombo savanna of Southern Africa. Biomass in the Cerrado varies from 1.9 Mg C ha-1 \\(grassy campo limpo\\) to 30.5 Mg C ha-1 \\(woody cerradão\\). Cerrado vegetation can be highly productive; annual net ecosystem exchange fluxes as high as 2.5 Mg C ha-1 yr-1 have been measured although lower values are more common. Assuming approximately 40 years of land use conversion and an average net biomass change \\(29 Mg C ha-1\\), this would lead to an average loss of C from the Cerrado of nearly 0.1 Pg C y-1. These values can be higher if belowground biomass is included as in Cerrado the ratio of belowground to aboveground biomass reaches values as high as 7.7. Fire is a principle factor controlling vegetation dynamics in the Cerrado \\(especially the ratio of grass to woody biomass\\). Frequent fires kill trees and shrubs favoring grasses favoring more open vegetation types. Inversely fire suppression favors woody growth. Advances in agricultural productivity have made the Cerrado the leading region of Brazil for beef cattle production and soybean production. It is estimated that between 40% and 55% of the region has been converted to pasture and other agricultural uses with peak rates in the early 1970's. Increasing international demand of biofuels represents a new aspect of land use in the region. Soil organic matter stocks exceed biomass stocks and data on soil C storage with conversion of native savanna into pasture indicated that well-managed, cultivated pastures may provide

  8. Final Report on "Rising CO2 and Long-term Carbon Storage in Terrestrial Ecosystems: An Empirical Carbon Budget Validation"

    Energy Technology Data Exchange (ETDEWEB)

    J. Patrick Megonigal; Bert G. Drake

    2010-08-27

    The primary goal of this report is to report the results of Grant DE-FG02-97ER62458, which began in 1997 as Grant DOE-98-59-MP-4 funded through the TECO program. However, this project has a longer history because DOE also funded this study from its inception in 1985 through 1997. The original grant was focused on plant responses to elevated CO2 in an intact ecosystem, while the latter grant was focused on belowground responses. Here we summarize the major findings across the 25 years this study has operated, and note that the experiment will continue to run through 2020 with NSF support. The major conclusions of the study to date are: (1 Elevated CO2 stimulated plant productivity in the C3 plant community by ~30% during the 25 year study. The magnitude of the increase in productivity varied interannually and was sometime absent altogether. There is some evidence of down-regulation at the ecosystem level across the 25 year record that may be due to interactions with other factors such as sea-level rise or long-term changes in N supply; (2) Elevated CO2 stimulated C4 productivity by <10%, perhaps due to more efficient water use, but C3 plants at elevated CO2 did not displace C4 plants as predicted; (3) Increased primary production caused a general stimulation of microbial processes, but there were both increases and decreases in activity depending on the specific organisms considered. An increase in methanogenesis and methane emissions implies elevated CO2 may amplify radiative forcing in the case of wetland ecosystems; (4) Elevated CO2 stimulated soil carbon sequestration in the form of an increase in elevation. The increase in elevation is 50-100% of the increase in net ecosystem production caused by elevated CO2 (still under analysis). The increase in soil elevation suggests the elevated CO2 may have a positive outcome for the ability of coastal wetlands to persist despite accelerated sea level rise; (5) Crossing elevated CO2 with elevated N causes the elevated CO

  9. Sink or link? The bacterial role in benthic carbon cycling in the Arabian Sea's oxygen minimum zone

    Science.gov (United States)

    Pozzato, L.; Van Oevelen, D.; Moodley, L.; Soetaert, K.; Middelburg, J. J.

    2013-11-01

    The bacterial loop, the consumption of dissolved organic matter (DOM) by bacteria and subsequent transfer of bacterial carbon to higher trophic levels, plays a prominent role in pelagic food webs. However, its role in sedimentary ecosystems is not well documented. Here we present the results of isotope tracer experiments performed under in situ oxygen conditions in sediments from inside and outside the Arabian Sea's oxygen minimum zone (OMZ) to study the importance of the microbial loop in this setting. Particulate organic matter, added as phytodetritus, was processed by bacteria, protozoa and metazoans, while dissolved organic matter was processed only by bacteria and there was very little, if any, transfer to higher trophic levels within the 7 day experimental period. This lack of significant transfer of bacterial-derived carbon to metazoan consumers indicates that the bacterial loop is rather inefficient, in sediments both inside and outside the OMZ. Moreover, metazoans directly consumed labile particulate organic matter resources and thus competed with bacteria for phytodetritus.

  10. Preliminary results in larger benthic foraminifera assemblage in a mixed siliciclastic-carbonate platform from the Upper Cretaceous of the External Prebetic Domain (Valencia province, SE Spain)

    Science.gov (United States)

    Robles-Salcedo, Raquel; Vicedo, Vicent

    2016-04-01

    In the External Prebetic Domain (Betic Mountain Range, Valencia province, SE Spain) it is difficult to find good outcrops to study larger benthic foraminifera (LBF), particularly in the Upper Cretaceous deposits, because of three main reasons. During the Upper Cretaceous, the complex paleogeography in the northern Prebetic Domain developed a complex system of shallow-water platforms. This is directly linked to the complexity in the distribution of the facies observed nowadays, which may change drastically in lateral, closely related outcrops having a special negative impact in the lateral extension of stratigraphical levels containing LBF. The second reason is the nature of the shallow water environments in which the larger foraminifera lived. The local continental influence derived in the establishment of very complex mixed platforms. Thus, there is not a complete register through carbonate rocks, but an alternation of microconglomerates, sandstones, calcarenites and carbonates that can be observed in the stratigraphic series of the Upper Cretaceous. This affects negatively in observing changes in the evolutionary trends of taxa. The third reason difficulting the study of LBF in northern localities of the Prebetic Domain is diagenetic. Dolomitization affects a huge part of the Mesozoic rocks deleting all fossil microfauna in the affected rocks. Such three reasons are behind the difficulty in developing correlations and having a comprehensive understanding of the biostratigraphy and phylogeny of the taxa involved. However, after several field trips developed in the northern Prebetic area, an excellent reference section for the study of the LBF in the Prebetic Domain has been identified in the surroundings of the Pinet village (Valencia province). Here, a relatively continuous section with scarce dolomitization and good conditions of accessibility exists. The larger foraminifera assemblages appering in the Pinet section will be compared with other paleobiogeographic

  11. Impacts of future climate change on the carbon budget of northern high-latitude terrestrial ecosystems: An analysis using ISI-MIP data

    Science.gov (United States)

    Ito, Akihiko; Nishina, Kazuya; Noda, Hibiki M.

    2016-09-01

    This paper assesses future changes in the carbon budgets of northern terrestrial ecosystems (above 60°N) using data from the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). By analyzing simulations from seven biome models driven by five climate scenarios under two representative concentration pathways (RCP2.6 and RCP8.5), the range of responses and their uncertainty in the 21st century was evaluated. The biome models consistently simulated a gradual increase in vegetation productivity driven by an elevated atmospheric CO2 concentration and a longer growing period. By the 2090s, most simulations showed average net carbon uptake into the northern terrestrial ecosystems of +27 Pg C for RCP2.6 and +48 Pg C for RCP8.5. These estimates showed a wide range of variability among simulations, especially for soil carbon stocks. Even under low greenhouse gas concentrations (RCP2.6), most simulations indicated that vegetation productivity and biomass would change by more than 10%, implying that it will be difficult to completely prevent climatic impacts in northern regions. Simulated spatial patterns and seasonality in the carbon budget can be used to identify sensitive areas and seasons, allowing for improved monitoring. Further research combining observations and modeling will be required to reduce estimation uncertainty and devise ecosystem management options.

  12. Nanophase Carbonates on Mars: Does Evolved Gas Analysis of Nanophase Carbonates Reveal a Large Organic Carbon Budget in Near-Surface Martian Materials?

    Science.gov (United States)

    Archer, P. Douglas, Jr.; Niles, Paul B.; Ming, Douglas W.; Sutter, Brad; Eigenbrode, Jen

    2015-01-01

    Evolved Gas Analysis (EGA), which involves heating a sample and monitoring the gases released, has been performed on Mars by the Viking gas chromatography/mass spectrometry instruments, the Thermal and Evolved Gas Analyzer (TEGA) on the Phoenix lander, and the Sample Analysis at Mars (SAM) instrument on the Mars Science Laboratory. All of these instruments detected CO2 released during sample analysis at abundances of approx. 0.1 to 5 wt% assuming a carbonate source. The source of the CO2 can be constrained by evaluating the temperature of the gas release, a capability of both the TEGA and SAM instruments. The samples analyzed by SAM show that the majority of the CO2 is released below 400C, much lower than traditional carbonate decomposition temperatures which can be as low as 400C for some siderites, with magnesites and calcites decomposing at even higher temperatures. In addition to mineralogy, decomposition temperature can depend on particle size (among other factors). If carbonates formed on Mars under low temperature and relative humidity conditions, the resulting small particle size (nanophase) carbonates could have low decomposition temperatures. We have found that calcite can be synthesized by exposing CaO to water vapor and CO2 and that the resulting mineral has an EGA peak of approx. 550C for CO2, which is about 200C lower than for other calcites. Work is ongoing to produce Fe and Mg-bearing carbonates using the same process. Current results suggest that nanophase calcium carbonates cannot explain the CO2 released from martian samples. If the decomposition temperatures of Mg and Fe-bearing nanophase carbonates are not significantly lower than 400C, other candidate sources include oxalates and carboxylated organic molecules. If present, the abundance of organic carbon in these samples could be greater than 0.1 wt % (1000s of ppm), a signficant departure from the paradigm of the organic-poor Mars based on Viking results.

  13. Nanophase Carbonates on Mars: Does Evolved Gas Analysis of Nanophase Carbonates Reveal a Large Organic Carbon Budget in Near-surface Martian Materials?

    Science.gov (United States)

    Archer, P. D., Jr.; Ming, D. W.; Sutter, B.; Niles, P. B.; Eigenbrode, J. L.

    2015-12-01

    Evolved Gas Analysis (EGA), which involves heating a sample and monitoring the gases released, has been performed on Mars by the Viking gas chromatography/mass spectrometry instruments, the Thermal and Evolved Gas Analyzer (TEGA) on the Phoenix lander, and the Sample Analysis at Mars (SAM) instrument on the Mars Science Laboratory. All of these instruments detected CO2 released during sample analysis at abundances of ~0.1 to 5 wt% assuming a carbonate source. The source of the CO2 can be constrained by evaluating the temperature of the gas release, a capability of both the TEGA and SAM instruments. The samples analyzed by SAM show that the majority of the CO2is released below 400 °C, much lower than traditional carbonate decomposition temperatures which can be as low as 400 °C for some siderites, with magnesites and calcites decomposing at even higher temperatures. In addition to mineralogy, decomposition temperature can depend on particle size (among other factors). If carbonates formed on Mars under low temperature and relative humidity conditions, the resulting small particle size (nanophase) carbonates could have low decomposition temperatures. We have found that calcite can be synthesized by exposing CaO to water vapor and CO2 and that the resulting mineral has an EGA peak of ~550 °C for CO2, which is about 200 °C lower than for other calcites. Work is ongoing to produce Fe and Mg-bearing carbonates using the same process. Current results suggest that nanophase calcium carbonates cannot explain the CO2 released from martian samples. If the decomposition temperatures of Mg and Fe-bearing nanophase carbonates are not significantly lower than 400 °C, other candidate sources include oxalates and carboxylated organic molecules. If present, the abundance of organic carbon in these samples could be > 0.1 wt % (1000s of ppm), a signficant departure from the paradigm of the organic-poor Mars based on Viking results.

  14. Carbon budget of tropical forests in Southeast Asia and the effects of deforestation: an approach using a process-based model and field measurements

    Directory of Open Access Journals (Sweden)

    M. Adachi

    2011-09-01

    Full Text Available More reliable estimates of the carbon (C stock within forest ecosystems and C emission induced by deforestation are urgently needed to mitigate the effects of emissions on climate change. A process-based terrestrial biogeochemical model (VISIT was applied to tropical primary forests of two types (a seasonal dry forest in Thailand and a rainforest in Malaysia and one agro-forest (an oil palm plantation in Malaysia to estimate the C budget of tropical ecosystems in Southeast Asia, including the impacts of land-use conversion. The observed aboveground biomass in the seasonal dry tropical forest in Thailand (226.3 t C ha−1 and the rainforest in Malaysia (201.5 t C ha−1 indicate that tropical forests of Southeast Asia are among the most C-abundant ecosystems in the world. The model simulation results in rainforests were consistent with field data, except for the NEP, however, the VISIT model tended to underestimate C budget and stock in the seasonal dry tropical forest. The gross primary production (GPP based on field observations ranged from 32.0 to 39.6 t C ha−1 yr−1 in the two primary forests, whereas the model slightly underestimated GPP (26.5–34.5 t C ha−1 yr−1. The VISIT model appropriately captured the impacts of disturbances such as deforestation and land-use conversions on the C budget. Results of sensitivity analysis showed that the proportion of remaining residual debris was a key parameter determining the soil C budget after the deforestation event. According to the model simulation, the total C stock (total biomass and soil C of the oil palm plantation was about 35% of the rainforest's C stock at 30 yr following initiation of the plantation. However, there were few field data of C budget and stock, especially in oil palm plantation. The C budget of each ecosystem must be evaluated over the long term using both the model simulations and observations to

  15. Carbon budget of tropical forests in Southeast Asia and the effects of deforestation: an approach using a process-based model and field measurements

    Science.gov (United States)

    Adachi, M.; Ito, A.; Ishida, A.; Kadir, W. R.; Ladpala, P.; Yamagata, Y.

    2011-09-01

    More reliable estimates of the carbon (C) stock within forest ecosystems and C emission induced by deforestation are urgently needed to mitigate the effects of emissions on climate change. A process-based terrestrial biogeochemical model (VISIT) was applied to tropical primary forests of two types (a seasonal dry forest in Thailand and a rainforest in Malaysia) and one agro-forest (an oil palm plantation in Malaysia) to estimate the C budget of tropical ecosystems in Southeast Asia, including the impacts of land-use conversion. The observed aboveground biomass in the seasonal dry tropical forest in Thailand (226.3 t C ha-1) and the rainforest in Malaysia (201.5 t C ha-1) indicate that tropical forests of Southeast Asia are among the most C-abundant ecosystems in the world. The model simulation results in rainforests were consistent with field data, except for the NEP, however, the VISIT model tended to underestimate C budget and stock in the seasonal dry tropical forest. The gross primary production (GPP) based on field observations ranged from 32.0 to 39.6 t C ha-1 yr-1 in the two primary forests, whereas the model slightly underestimated GPP (26.5-34.5 t C ha-1 yr-1). The VISIT model appropriately captured the impacts of disturbances such as deforestation and land-use conversions on the C budget. Results of sensitivity analysis showed that the proportion of remaining residual debris was a key parameter determining the soil C budget after the deforestation event. According to the model simulation, the total C stock (total biomass and soil C) of the oil palm plantation was about 35% of the rainforest's C stock at 30 yr following initiation of the plantation. However, there were few field data of C budget and stock, especially in oil palm plantation. The C budget of each ecosystem must be evaluated over the long term using both the model simulations and observations to understand the effects of climate and land-use conversion on C budgets in tropical forest

  16. Carbon budget of tropical forests in Southeast Asia and the effects of deforestation: an approach using a process-based model and field measurements

    Directory of Open Access Journals (Sweden)

    M. Adachi

    2011-03-01

    Full Text Available More reliable estimates of carbon (C stock within forest ecosystems and C emission induced by deforestation are urgently needed to mitigate the effects of emissions on climate change. A process-based terrestrial biogeochemical model (VISIT was applied to tropical primary forests of two types (a seasonal dry forest in Thailand and a rainforest in Malaysia and one agro-forest (an oil palm plantation in Malaysia to estimate the C budget of tropical ecosystems, including the impacts of land-use conversion, in Southeast Asia. Observations and VISIT model simulations indicated that the primary forests had high photosynthetic uptake: gross primary production was estimated at 31.5–35.5 t C ha−1 yr−1. In the VISIT model simulation, the rainforest had a higher total C stock (plant biomass and soil organic matter, 301.5 t C ha−1 than that in the seasonal dry forest (266.5 t C ha−1 in 2008. The VISIT model appropriately captured the impacts of disturbances such as deforestation and land-use conversions on the C budget. Results of sensitivity analysis implied that the ratio of remaining residual debris was a key parameter determining the soil C budget after deforestation events. The C stock of the oil palm plantation was about 46% of the rainforest's C at 30 yr following initiation of the plantation, when the ratio of remaining residual debris was assumed to be about 33%. These results show that adequate forest management is important for reducing C emission from soil and C budget of each ecosystem must be evaluated over a long term using both the model simulations and observations.

  17. System Budgets

    DEFF Research Database (Denmark)

    Jeppesen, Palle

    1996-01-01

    The lecture note is aimed at introducing system budgets for optical communication systems. It treats optical fiber communication systems (six generations), system design, bandwidth effects, other system impairments and optical amplifiers.......The lecture note is aimed at introducing system budgets for optical communication systems. It treats optical fiber communication systems (six generations), system design, bandwidth effects, other system impairments and optical amplifiers....

  18. Budget timetable

    Science.gov (United States)

    This is a timetable for congressional action under the Balanced Budget and Emergency Deficit Control Act of 1985 (Gramm-Rudman-Hollings). These deadlines apply to fiscal years (FY) 1987-1991. The Congress missed a number of these deadlines last year. The deficit reduction measures in Gramm-Rudman-Hollings would lead to a balanced budget in 1991.

  19. DCS Budget Tracking System

    Data.gov (United States)

    Social Security Administration — DCS Budget Tracking System database contains budget information for the Information Technology budget and the 'Other Objects' budget. This data allows for monitoring...

  20. A high-resolution benthic stable-isotope record for the South Atlantic: Implications for orbital-scale changes in Late Paleocene-Early Eocene climate and carbon cycling

    Science.gov (United States)

    Littler, Kate; Röhl, Ursula; Westerhold, Thomas; Zachos, James C.

    2014-09-01

    The Late Paleocene and Early Eocene were characterized by warm greenhouse climates, punctuated by a series of rapid warming and ocean acidification events known as “hyperthermals”, thought to have been paced or triggered by orbital cycles. While these hyperthermals, such as the Paleocene Eocene Thermal Maximum (PETM), have been studied in great detail, the background low-amplitude cycles seen in carbon and oxygen-isotope records throughout the Paleocene-Eocene have hitherto not been resolved. Here we present a 7.7 million year (myr) long, high-resolution, orbitally-tuned, benthic foraminiferal stable-isotope record spanning the late Paleocene and early Eocene interval (∼52.5-60.5 Ma) from Ocean Drilling Program (ODP) Site 1262, South Atlantic. This high resolution (∼2-4 kyr) record allows the changing character and phasing of orbitally-modulated cycles to be studied in unprecedented detail as it reflects the long-term trend in carbon cycle and climate over this interval. The main pacemaker in the benthic oxygen-isotope (δ18O) and carbon-isotope (δ13C) records from ODP Site 1262, are the long (405 kyr) and short (100 kyr) eccentricity cycles, and precession (21 kyr). Obliquity (41 kyr) is almost absent throughout the section except for a few brief intervals where it has a relatively weak influence. During the course of the Early Paleogene record, and particularly in the latest Paleocene, eccentricity-paced negative carbon-isotope excursions (δ13C, CIEs) and coeval negative oxygen-isotope (δ18O) excursions correspond to low carbonate (CaCO3) and coarse fraction (%CF) values due to increased carbonate dissolution, suggesting shoaling of the lysocline and accompanied changes in the global exogenic carbon cycle. These negative CIEs and δ18O events coincide with maxima in eccentricity, with changes in δ18O leading changes in δ13C by ∼6 (±5) kyr in the 405-kyr band and by ∼3 (±1) kyr in the higher frequency 100-kyr band on average. However, these

  1. Budget of organic carbon in the North-Western Mediterranean open sea over the period 2004-2008 using 3-D coupled physical-biogeochemical modeling

    Science.gov (United States)

    Ulses, C.; Auger, P.-A.; Soetaert, K.; Marsaleix, P.; Diaz, F.; Coppola, L.; Herrmann, M. J.; Kessouri, F.; Estournel, C.

    2016-09-01

    A 3-D hydrodynamic-biogeochemical coupled model has been used to estimate a budget of organic carbon and its interannual variability over the 5 year period 2004-2008 in the North-Western Mediterranean Open Sea (NWMOS). The comparison of its results with in situ and satellite observations reveals that the timing and the magnitude of the convection and bloom processes during the study period, marked by contrasted atmospheric conditions, are reasonably well reproduced by the model. Model outputs show that the amount of nutrients annually injected into the surface layer is clearly linked to the intensity of the events of winter convection. During cold winters, primary production is reduced by intense mixing events but then spectacularly increases when the water column restratifies. In contrast, during mild winters, the primary production progressively and continuously increases, sustained by moderate new production followed by regenerated production. Overall, interannual variability in the annual primary production is low. The export in subsurface and at middepth is however affected by the intensity of the convection process, with annual values twice as high during cold winters than during mild winters. Finally, the estimation of a global budget of organic carbon reveals that the NWMOS acts as a sink for the shallower areas and as a source for the Algerian and Balearic subbasins.

  2. BLAZE, a novel Fire-Model for the CABLE Land-Surface Model applied to a Re-Assessment of the Australian Continental Carbon Budget

    Science.gov (United States)

    Nieradzik, L. P.; Haverd, V. E.; Briggs, P.; Meyer, C. P.; Canadell, J.

    2015-12-01

    Fires play a major role in the carbon-cycle and the development of global vegetation, especially on the continent of Australia, where vegetation is prone to frequent fire occurences and where regional composition and stand-age distribution is regulated by fire. Furthermore, the probable changes of fire behaviour under a changing climate are still poorly understood and require further investigation.In this presentation we introduce the fire-model BLAZE (BLAZe induced land-atmosphere flux Estimator), designed for a novel approach to simulate fire-frequencies, fire-intensities, fire related fluxes and the responses in vegetation. Fire frequencies are prescribed using SIMFIRE (Knorr et al., 2014) or GFED3 (e.g. Giglio et al., 2013). Fire-Line-Intensity (FLI) is computed from meteorological information and fuel loads which are state variables within the C-cycle component of CABLE (Community Atmosphere-Biosphere-Land Exchange model). This FLI is used as an input to the tree-demography model POP(Population-Order-Physiology; Haverd et al., 2014). Within POP the fire-mortality depends on FLI and tree height distribution. Intensity-dependent combustion factors (CF) are then generated for and applied to live and litter carbon pools as well as the transfers from live pools to litter caused by fire. Thus, both fire and stand characteristics are taken into account which has a legacy effect on future events. Gross C-CO2 emissions from Australian wild fires are larger than Australian territorial fossil fuel emissions. However, the net effect of fire on the Australian terrestrial carbon budget is unknown. We address this by applying the newly-developed fire module, integrated within the CABLE land surface model, and optimised for the Australian region, to a reassessment of the Australian Terrestrial Carbon Budget.

  3. A novel Fire-Model for the CABLE Land Surface Model applied to a Re-assessment of the Australian Continental Carbon Budget

    Science.gov (United States)

    Nieradzik, L. P.; Haverd, V. E.; Briggs, P.; Meyer, C. P.; Canadell, J.

    2014-12-01

    Fires play a major role in the carbon-cycle and the development of global vegetation, especially on the continent of Australia, where vegetation is prone to frequent fire occurences and where regional composition and stand-age distribution is regulated by fire. Furthermore, the probable changes of fire behaviour under a changing climate are still poorly understood and require further investigation.In this presentation we introduce a novel approach to simulate fire-frequencies, fire-intensities and the responses in vegetation. Fire frequencies are prescribed using SIMFIRE (Knorr et al., 2014) or GFED3 (e.g. Giglio et al., 2013). Fire-Line-Intensity (FLI) is computed from meteorological information and fuel loads which are state variables within the C-cycle component of CABLE. This FLI is used as an input to the tree-demography model POP (Population-Order-Physiology; Haverd et al., 2014). Within POP the fire-mortality depends on FLI and tree height distribution.Intensity-dependent combustion factors (CF) are then generated for and applied to live and litter carbon pools as well as the transfers from live pools to litter caused by fire. Thus, both fire and stand characteristics are taken into account which has a legacy effect on future events. Gross C-CO2 emissions from Australian wild fires are larger than Australian territorial fossil fuel emissions. However, the net effect of fire on the Australian terrestrial carbon budget is unknown. We address this by applying the newly-developed fire module, integrated within the CABLE land surface model, and optimised for the Australian region, to a reassessment of the Australian Terrestrial Carbon Budget.

  4. Changes of global terrestrial carbon budget and major drivers in recent 30 years simulated using the remote sensing driven BEPS model

    Science.gov (United States)

    Ju, W.; Chen, J.; Liu, R.; Liu, Y.

    2013-12-01

    The process-based Boreal Ecosystem Productivity Simulator (BEPS) model was employed in conjunction with spatially distributed leaf area index (LAI), land cover, soil, and climate data to simulate the carbon budget of global terrestrial ecosystems during the period from 1981 to 2008. The BEPS model was first calibrated and validated using gross primary productivity (GPP), net primary productivity (NPP), and net ecosystem productivity (NEP) measured in different ecosystems across the word. Then, four global simulations were conducted at daily time steps and a spatial resolution of 8 km to quantify the global terrestrial carbon budget and to identify the relative contributions of changes in climate, atmospheric CO2 concentration, and LAI to the global terrestrial carbon sink. The long term LAI data used to drive the model was generated through fusing Moderate Resolution Imaging Spectroradiometer (MODIS) and historical Advanced Very High Resolution Radiometer (AVHRR) data pixel by pixel. The meteorological fields were interpolated from the 0.5° global daily meteorological dataset produced by the land surface hydrological research group at Princeton University. The results show that the BEPS model was able to simulate carbon fluxes in different ecosystems. Simulated GPP, NPP, and NEP values and their temporal trends exhibited distinguishable spatial patterns. During the period from 1981 to 2008, global terrestrial ecosystems acted as a carbon sink. The averaged global totals of GPP NPP, and NEP were 122.70 Pg C yr-1, 56.89 Pg C yr-1, and 2.76 Pg C yr-1, respectively. The global totals of GPP and NPP increased greatly, at rates of 0.43 Pg C yr-2 (R2=0.728) and 0.26 Pg C yr-2 (R2=0.709), respectively. Global total NEP did not show an apparent increasing trend (R2= 0.036), averaged 2.26 Pg C yr-1, 3.21 Pg C yr-1, and 2.72 Pg C yr-1 for the periods from 1981 to 1989, from 1990 to 1999, and from 2000 to 2008, respectively. The magnitude and temporal trend of global

  5. Carbon and Water Budgets in Multiple Wheat-Based Cropping Systems in the Inland Pacific Northwest US: Comparison of CropSyst Simulations with Eddy Covariance Measurements

    Directory of Open Access Journals (Sweden)

    Jinshu Chi

    2017-05-01

    Full Text Available Accurate carbon and water flux simulations for croplands are greatly dependent on high quality representation of management practices and meteorological conditions, which are key drivers of the surface-atmosphere exchange processes. Fourteen site-years of carbon and water fluxes were simulated using the CropSyst model over four agricultural sites in the inland Pacific Northwest (iPNW US from October 1, 2011 to September 30, 2015. Model performance for field-scale net ecosystem exchange of CO2 (NEE and evapotranspiration (ET was evaluated by comparing simulations with long-term eddy covariance measurements. The model captured the temporal variations of NEE and ET reasonably well with an overall r of 0.78 and 0.80, and a low RMSE of 1.82 g C m−2 d−1 and 0.84 mm d−1 for NEE and ET, respectively. The model slightly underestimated NEE and ET by 0.51 g C m−2 d−1 and 0.09 mm d−1, respectively. ET simulations showed better agreement with eddy covariance measurements than NEE. The model performed much better for the sites with detailed initial conditions (e.g., SOC content and management practice information (e.g., tillage type. The CropSyst results showed that the winter wheat fields could be annual net carbon sinks or close to neutral with the net ecosystem carbon balance (NECB ranging from 92 to −17 g C m−2, while the spring crop fields were net carbon sources or neutral with an annual NECB of −327 to −3 g C m−2. Simulations for the paired tillage sites showed that the no-till site resulted in lower CO2 emissions for the crop rotations of winter wheat-spring garbanzo, but had higher carbon loss into the atmosphere for spring canola compared to the conventional tillage site. Water budgets did not differ significantly between the two tillage systems. Winter wheat in the high-rainfall area had higher crop yields and water use efficiency but emitted larger amounts of CO2 into the atmosphere than in the low-rainfall area. Based on

  6. The greenhouse gas balance of the oil palm industry in Colombia: a preliminary analysis. II. Greenhouse gas emissions and the carbon budget

    Directory of Open Access Journals (Sweden)

    Ian E Henson

    2012-09-01

    Full Text Available In the preceding paper we examined carbon sequestration in oil palm plantations and in mill products and by-products as part of a study of the greenhouse gas balance of palm oil production in Colombia, showing how this has changed over time. Here, we look at the opposing processes of greenhouse gas (GHG emission and calculate the resulting net carbon budget for the industry. The main emission sources, in decreasing order of magnitude, assessed using "default" or "most probable" options, were found to be land use change (40.9% of total, mill methane production (21.4%, direct use of fossil fuel (18.5%, indirect use of fossil fuel (11.9% and nitrous oxide production (7.3%. The total (gross emissions, expressed in carbon equivalents (Ceq., were less than the amount of sequestered carbon, resulting in a positive net Ceq. balance. All oil palm growing regions showed a net gain with the exception of the western zone, where emissions due to land-use change were judged to be substantial. Of the 11 alternative scenarios tested, only three resulted in Ceq. balances lower than the default and only two gave a negative balance

  7. The ORCA West Coast Regional Project - Atmospheric Top-Down Modeling to constrain Regional Carbon Budgets at high Temporal and Spatial Resolution

    Science.gov (United States)

    Goeckede, M.; Michalak, A. M.; Vickers, D.; Turner, D.; Law, B.

    2008-12-01

    The ORCA project aims at determining the regional carbon balance of Oregon, California and Washington, with a special focus on the effect of disturbance history and climate variability on carbon sources and sinks. ORCA provides a regional test of the overall NACP strategy by demonstrating bottom-up and top-down modeling approaches to derive carbon balances at subregional to regional scales. The ORCA top-down modeling component has been set up to capture flux variability on the regional scale at high temporal and spatial resolution. Atmospheric transport is simulated coupling the mesoscale model WRF (Weather Research and Forecast) with the STILT (Stochastic Time Inverted Lagrangian Transport) footprint model. This setup allows identifying sources and sinks that influence atmospheric observations with highly resolved mass transport fields and realistic turbulent mixing. High-precision atmospheric CO2 concentrations are monitored as continuous time series in hourly timesteps at 5 locations within the model domain, west to east from the Pacific Coast to the Great Basin, and include two flux sites for evaluation of computed fluxes. Terrestrial biosphere carbon fluxes are simulated at an effective spatial resolution of smaller than 1km and subdaily timesteps, considering effects of ecoregion, land cover type and disturbance regime on the carbon budgets. Flux computation assimilates high-resolution remote sensing products (e.g. LandSat, MODIS) and interpolated surface meteorology (DayMet, SOGS, PRISM). We present results on regional carbon budgets for the ORCA modeling domain that have been optimized using Bayesian inversion and the information provided by the network of high-precision CO2 observations. We address the influence of spatial and temporal resolution in the general modeling setup on the findings, and test the level of detail that can be resolved by top-down modeling on the regional scale, given the uncertainties introduced by various sources for model

  8. Food web flows through a sub-arctic deep-sea benthic community

    NARCIS (Netherlands)

    Gontikaki, E.; Van Oevelen, D.; Soetaert, K.E.R.; Prof. Witte, U.

    2011-01-01

    The benthic food web of the deep Faroe–Shetland Channel (FSC) was modelled by using the linear inverse modelling methodology. The reconstruction of carbon pathways by inverse analysis was based on benthic oxygen uptake rates, biomass data and transfer of labile carbon through the food web as

  9. Food web flows through a sub-arctic deep-sea benthic community

    NARCIS (Netherlands)

    Gontikaki, E.; Van Oevelen, D.; Soetaert, K.E.R.; Prof. Witte, U.

    2011-01-01

    The benthic food web of the deep Faroe–Shetland Channel (FSC) was modelled by using the linear inverse modelling methodology. The reconstruction of carbon pathways by inverse analysis was based on benthic oxygen uptake rates, biomass data and transfer of labile carbon through the food web as reveale

  10. Food web flows through a sub-arctic deep-sea benthic community

    NARCIS (Netherlands)

    Gontikaki, E.; Van Oevelen, D.; Soetaert, K.E.R.; Prof. Witte, U.

    2011-01-01

    The benthic food web of the deep Faroe–Shetland Channel (FSC) was modelled by using the linear inverse modelling methodology. The reconstruction of carbon pathways by inverse analysis was based on benthic oxygen uptake rates, biomass data and transfer of labile carbon through the food web as reveale

  11. BEYOND BUDGETING

    Directory of Open Access Journals (Sweden)

    Edo Cvrkalj

    2015-12-01

    Full Text Available Traditional budgeting principles, with strictly defined business goals, have been, since 1998, slowly growing into more sophisticated and organization-adjusted alternative budgeting concepts. One of those alternative concepts is the “Beyond budgeting” model with an implemented performance effects measuring process. In order for the model to be practicable, budget planning and control has to be reoriented to the “bottom up” planning and control approach. In today’s modern business surroundings one has to take both present and future opportunities and threats into consideration, by valorizing them in a budget which would allow a company to realize a whole pallet of advantages over the traditional budgeting principles which are presented later in the article. It is essential to emphasize the importance of successfully implementing the new budgeting principles within an organization. If the implementation has been lacking and done without a higher goal in mind, it is easily possible that the process has been implemented without coordination, planning and control framework within the organization itself. Further in the article we present an overview of managerial techniques and instruments within the “Beyond budgeting” model such as balanced scorecard, rolling forecast, dashboard, KPI and other supporting instruments. Lastly we define seven steps for implementing the “Beyond budgeting” model and offer a comparison of “Beyond budgeting” model against traditional budgeting principles which lists twelve reasons why “Beyond budgeting” is better suited to modern and market-oriented organizations. Each company faces those challenges in their own characteristic way but implementing new dynamic planning models will soon become essential for surviving in the market.

  12. Forecasting carbon budget under climate change and CO2 fertilization for subtropical region in China using integrated biosphere simulator (IBIS) model

    Science.gov (United States)

    Zhu, Q.; Jiang, H.; Liu, J.; Peng, C.; Fang, X.; Yu, S.; Zhou, G.; Wei, X.; Ju, W.

    2011-01-01

    The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr-1 during the last half of the 21st century. An NPP increase of about 24 Mt C by the end of the 21st century was estimated with the combined effects of increasing CO2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr-1. NEP will increase to about 5 Mt C yr-1 by the end of the 21st century with the increasing atmospheric CO2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang's forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO2 concentration will have little

  13. Toward the definition of a carbon budget model: seasonal variation and temperature effect on respiration rate of vegetative and reproductive organs of pistachio trees (Pistacia vera).

    Science.gov (United States)

    Marra, Francesco P; Barone, Ettore; La Mantia, Michele; Caruso, Tiziano

    2009-09-01

    This study, as a preliminary step toward the definition of a carbon budget model for pistachio trees (Pistacia vera L.), aimed at estimating and evaluating the dynamics of respiration of vegetative and reproductive organs of pistachio tree. Trials were performed in 2005 in a commercial orchard located in Sicily (370 m a.s.l.) on five bearing 20-year-old pistachio trees of cv. Bianca grafted onto Pistachio terebinthus L. Growth analyses and respiration measurements were done on vegetative (leaf) and reproductive (infructescence) organs during the entire growing season (April-September) at biweekly intervals. Results suggested that the respiration rates of pistachio reproductive and vegetative organs were related to their developmental stage. Both for leaf and for infructescence, the highest values were observed during the earlier stages of growth corresponding to the phases of most intense organ growth. The sensitivity of respiration activity to temperature changes, measured by Q(10), showed an increase throughout the transition from immature to mature leaves, as well as during fruit development. The data collected were also used to estimate the seasonal carbon loss by respiration activity for a single leaf and a single infructescence. The amount of carbon lost by respiration was affected by short-term temperature patterns, organ developmental stage and tissue function.

  14. Benthic contributions to Adriatic and Mediterranean biogeochemical cycles

    Science.gov (United States)

    Capet, Arthur; Lazzari, Paolo; Spagnoli, Federico; Bolzon, Giorgio; Solidoro, Cosimo

    2017-04-01

    The 3D biogeochemical BFM-OGSTM implementation currently exploited operationally in the Copernicus Marine Environment Monitoring Services Mediterranean Sea Monitoring and Forecasting Centre (CMEMS-Med-MFC; Lazzari et al., 2010) has been complemented with a benthic component. The approach followed that of (Capet et al 2016) and involved a vertically integrated benthic module accounting for the effect of environmental bottom conditions on diagenetic rates (aerobic mineralization, denitrification, nitrification) through transfer functions as well as the effect of waves and bottom currents on sediment deposition and resuspension. A balanced climatological year is simulated for various values of the resuspension parameters, using specifically calibrated transfer functions for the Adriatic Sea and generic formulations for the rest of the Mediterranean basin. The results serves the mapping of distinct provinces of the Adriatic Sea based on the benthic contributions biogeochemical budgets and the seasonal variability of benthic-pelagic fluxes. The differences with the non-benthic reference simulation are highlighted in details regarding the Adriatic, and more generally for the entire Mediterranean Sea. Lazzari, P., Teruzzi, A., Salon, S., Campagna, S., Calonaci, C., Colella, S., Tonani, M., Crise, A. (2010). Pre-operational short-term forecasts for Mediterranean Sea biogeochemistry. Ocean Science, 6(1), 25-39. Capet, A., Meysman, F. J., Akoumianaki, I., Soetaert, K., & Grégoire, M. (2016). Integrating sediment biogeochemistry into 3D oceanic models: A study of benthic-pelagic coupling in the Black Sea. Ocean Modelling, 101, 83-100.

  15. A 100-Year Retrospective Landscape-Level Carbon Budget for the Sooke Lake Watershed, British Columbia: Constraining Estimates of Terrestrial to Aquatic DOC Transfers.

    Science.gov (United States)

    Trofymow, J. A.; Smiley, B. P. K.

    2014-12-01

    To address how natural disturbance, forest harvest, and deforestation from reservoir creation affect landscape-level carbon (C) budgets, a retrospective C budget for the 8500 ha Sooke watershed from 1911 - 2012 was developed using historic spatial inventory and disturbance data. Data was input to a spatially-explicit version of the Carbon Budget Model-Canadian Forest Sector (CBM-CFS3), an inventory-based C budget model used to simulate forest C dynamics at multiple scales. In 1911 the watershed was dominated by mature/old Douglas-fir forests with aboveground biomass C (ABC) of 262 Mg C/ha and net ecosystem production (NEP) of 0.63 Mg C/ha/yr. Land was cleared around Sooke Lake, a dam built and lake expanded from 370 to 450 ha in 1915, 610 ha in 1970, 670 ha in 1980 and 810 ha in 2002. Along with deforestation, fires and localized harvest occurred from 1920 - 1940, reducing ABC to 189 Mg C/ha, with NEP varying from -1.63 to 0.13 Mg C/ha/yr. Distributed harvest occurred 1954 - 1998, with a minimum ABC of 148 Mg C/ha in 1991. By 2012 ABC (177 Mg C/ha) and NEP (2.29 Mg C/ha/yr) had increased. Over 100 years, 2430 ha forest was cut and replanted and 640 ha deforested. CBM-CFS3 includes transfers of dissolved organic C (DOC) to aquatic systems, however data has not been available to parameterize DOC flux. DOC fluxes are modelled as a fraction of decay loss from humified soil C with a default of 100% of losses to CO2 and 0% to DOC. Stream flow and [DOC] data from 1996 - 2012 for 3 watershed catchments, Rithet, Judge and Council were used to estimate annual DOC fluxes. Rithet, Judge and Council differed both in area % disturbed (logging or fire) over 100 years (39%, 93%, 91%) and in area % mature/old forest (>80yrs in 2012) (67%, 56%, 21%). DOC flux for Rithet and Judge ranged from 0.037 - 0.057 Mg C/ha/yr, Council averaged 0.017 Mg C/ha/yr. Low DOC fluxes were likely due to influences of a small lake in the catchment. Constraining CBM-CFS3 to observed DOC fluxes, required

  16. Modelling the phenology and carbon budget of major crops at the field scale, supported by remote sensing data

    Science.gov (United States)

    Sus, O.; Williams, M.

    2009-04-01

    Reducing uncertainties involved in estimating the carbon balance of croplands, which are most directly, intensively and continuously affected by human intervention (i.e. land-use), is an important step towards more precisely evaluating the overall terrestrial carbon balance. Human appropriation of the land surface and its production has direct consequences on issues such as the sustainability of ecosystem services and biogeophysical as well as biogeochemical parameters of affected areas. Moreover, cropland management and phenology explains a major component of the seasonality of carbon fluxes between the terrestrial biosphere and the atmosphere of agricultural regions. To address key research questions, crop functional types (CFTs) along with land management issues, need to be considered within state-of-the-art land surface models. In this study, we embedded a crop modelling approach within the Soil-Plant-Atmosphere model (SPA) in order to build a true cropland carbon mass balance model with an explicit carbon allocation and storage pattern. SPA is a process-based model that simulates ecosystem photosynthesis and water balance at fine temporal and spatial scales and has been intensively applied to and tested against natural ecosystems and their observed carbon fluxes. Here, new carbon pools (root, leaf, stem, storage organ) have been introduced into SPA and linked with a new dynamic carbon allocation pattern, which further allows for the remobilization of carbohydrates. The crop modelling philosophy in terms of assimilates partitioning and crop development is based on Penning de Vries et al., with the simulation of crop developmental rate further having been refined using a modified Wang and Engel model. SPA now realistically simulates the carbon fluxes and stocks, evolution of LAI, phenology and evapotranspiration for three major crop types (winter/spring wheat and barley, maize). We compared modelled values of carbon fluxes against observations measured at the

  17. Biodiversity in Benthic Ecology

    DEFF Research Database (Denmark)

    Friberg, Nikolai; Carl, J. D.

    Foreword: This proceeding is based on a set of papers presented at the second Nordic Benthological Meeting held in Silkeborg, November 13-14, 1997. The main theme of the meeting was biodiversity in benthic ecology and the majority of contributions touch on this subject. In addition, the proceeding...... contains papers which cover other themes thus continuing with the spirit of the meetings in the Nordic Benthological Society (NORBS) by being an open forum for exchanging knowledge on all aspects of benthic ecology. Overall, we feel the proceeding contains a wide selection of very interesting papers...... representing the state-of-the-art of benthic ecology research within, and to a lesser degree, outside the Nordic countries. We wish to thank all the authors for their inspirational contributions to the proceeding, but we feel that a special thanks is due to the invited speakers for their readiness to produce...

  18. Analysis of the uncertainty associated with national fossil fuel CO2 emissions datasets for use in the global Fossil Fuel Data Assimilation System (FFDAS) and carbon budgets

    Science.gov (United States)

    Song, Y.; Gurney, K. R.; Rayner, P. J.; Asefi-Najafabady, S.

    2012-12-01

    specific sectors required by FFDAS. Our results indicated that although the harmonization performed by Macknick generates better agreement among datasets, significant differences remain at national total level. For example, the CO2 emission span for most countries range from 10% to 12%; BP is generally the highest of the four datasets while IEA is typically the lowest; The US and China had the highest absolute span values but lower percentage span values compared to other countries. However, the US and China make up nearly one-half of the total global absolute span quantity. The absolute span value for the summation of national differences approaches 1 GtC/year in 2007, almost one-half of the biological "missing sink". The span value is used as a potential bias in a recalculation of global and regional carbon budgets to highlight the importance of fossil fuel CO2 emissions in calculating the missing sink. We conclude that if the harmonized span represents potential bias, calculations of the missing sink through forward budget or inverse approaches may be biased by nearly a factor of two.

  19. Modelling benthic biophysical drivers of ecosystem structure and biogeochemical response

    Science.gov (United States)

    Stephens, Nicholas; Bruggeman, Jorn; Lessin, Gennadi; Allen, Icarus

    2016-04-01

    The fate of carbon deposited at the sea floor is ultimately decided by biophysical drivers that control the efficiency of remineralisation and timescale of carbon burial in sediments. Specifically, these drivers include bioturbation through ingestion and movement, burrow-flushing and sediment reworking, which enhance vertical particulate transport and solute diffusion. Unfortunately, these processes are rarely satisfactorily resolved in models. To address this, a benthic model that explicitly describes the vertical position of biology (e.g., habitats) and biogeochemical processes is presented that includes biological functionality and biogeochemical response capturing changes in ecosystem structure, benthic-pelagic fluxes and biodiversity on inter-annual timescales. This is demonstrated by the model's ability to reproduce temporal variability in benthic infauna, vertical pore water nutrients and pelagic-benthic solute fluxes compared to in-situ data. A key advance is the replacement of bulk parameterisation of bioturbation by explicit description of the bio-physical processes responsible. This permits direct comparison with observations and determination of key parameters in experiments. Crucially, the model resolves the two-way interaction between sediment biogeochemistry and ecology, allowing exploration of the benthic response to changing environmental conditions, the importance of infaunal functional traits in shaping benthic ecological structure and the feedback the resulting bio-physical processes exert on pore water nutrient profiles. The model is actively being used to understand shelf sea carbon cycling, the response of the benthos to climatic change, food provision and other societal benefits.

  20. Constraining Daily-To-Annual Carbon Budgets in a Brackish Tidal Marsh in the San Francisco Bay Delta: Insights on Methane and Carbon Dioxide Fluxes from Eddy Covariance Measurements

    Science.gov (United States)

    Saraceno, J.; Anderson, F. E.; Knox, S.; Windham-Myers, L.; Bergamaschi, B. A.

    2016-12-01

    inorganic carbon, dissolved organic carbon and particulate organic carbon in order to better constrain ecosystem wide carbon budgets.

  1. 氮沉降对森林土壤碳收支机制的影响%Effects of nitrogen deposition on forest soil carbon budget mechanism

    Institute of Scientific and Technical Information of China (English)

    王汝南; 蔺兆兰; 王春梅

    2011-01-01

    森林土壤储存着全球陆地生态系统大约45%的碳,在维持全球碳平衡方面具有重要的作用.不断加剧的全球氮沉降对森林生态系统碳循环和碳吸存产生了深刻的影响,进而改变了森林生态系统的生产力和生物量积累.本文以欧洲和北美温带地区开展的有关氮沉降对森林生态系统影响的研究为基础,提炼出最可能决定加氮影响碳输入、输出效应方向和大小的因素:凋落物分解、细根周转、外生菌根真菌、土壤呼吸及可溶性有机碳淋失,并探讨了森林生态系统碳动态对氮沉降响应的不确定性.陆地生态系统碳氮循环密切相关,由于氮循环的复杂性,尽管以往碳循环研究都考虑了氮对碳循环的限制作用,但在碳氮循环耦合机理方面的研究还比较少见.在未来研究中,应通过探寻森林土壤碳氮相互作用特征,及土壤微生物、土壤酶等与土壤碳氮过程的互动机制,来增进氮沉降对森林碳储量和碳通量的理解.%Forest ecosystems contain 45 percent of the carbon stored in terrestrial biosphere with the majority of it stored in the soil,which plays a critical role in global carbon balance.In forest ecosystems, patterns of carbon sequestration and cycling are being influenced by elevated N deposition and anthropogenic N deposition have altered rates of productivity and biomass accumulation.Based on the studies about the impacts of nitrogen deposition for forest ecosystems conducted in temperate forest regions in Europe and North America, the paper refined decisive factors underlying the influence of nitrogen deposition on carbon budget in direction and scale: litter decomposition, fine root turnover, exogenous mycorrhizal fungi (EMF) productivity, soil respiration, dissolved organic carbon leaching.The uncertainties as to the interactions between forest ecosystem carbon dynamics and nitrogen deposition were also analyzed and discussed.Terrestrial carbon cycle

  2. Detecting small-scale spatial heterogeneity and temporal dynamics of soil organic carbon (SOC) stocks: a comparison between automatic chamber-derived C budgets and repeated soil inventories

    Science.gov (United States)

    Hoffmann, Mathias; Jurisch, Nicole; Garcia Alba, Juana; Albiac Borraz, Elisa; Schmidt, Marten; Huth, Vytas; Rogasik, Helmut; Rieckh, Helene; Verch, Gernot; Sommer, Michael; Augustin, Jürgen

    2017-03-01

    Carbon (C) sequestration in soils plays a key role in the global C cycle. It is therefore crucial to adequately monitor dynamics in soil organic carbon (ΔSOC) stocks when aiming to reveal underlying processes and potential drivers. However, small-scale spatial (10-30 m) and temporal changes in SOC stocks, particularly pronounced in arable lands, are hard to assess. The main reasons for this are limitations of the well-established methods. On the one hand, repeated soil inventories, often used in long-term field trials, reveal spatial patterns and trends in ΔSOC but require a longer observation period and a sufficient number of repetitions. On the other hand, eddy covariance measurements of C fluxes towards a complete C budget of the soil-plant-atmosphere system may help to obtain temporal ΔSOC patterns but lack small-scale spatial resolution. To overcome these limitations, this study presents a reliable method to detect both short-term temporal dynamics as well as small-scale spatial differences of ΔSOC using measurements of the net ecosystem carbon balance (NECB) as a proxy. To estimate the NECB, a combination of automatic chamber (AC) measurements of CO2 exchange and empirically modeled aboveground biomass development (NPPshoot) were used. To verify our method, results were compared with ΔSOC observed by soil resampling. Soil resampling and AC measurements were performed from 2010 to 2014 at a colluvial depression located in the hummocky ground moraine landscape of northeastern Germany. The measurement site is characterized by a variable groundwater level (GWL) and pronounced small-scale spatial heterogeneity regarding SOC and nitrogen (Nt) stocks. Tendencies and magnitude of ΔSOC values derived by AC measurements and repeated soil inventories corresponded well. The period of maximum plant growth was identified as being most important for the development of spatial differences in annual ΔSOC. Hence, we were able to confirm that AC-based C budgets are able

  3. Integrated carbon budget models for the Everglades terrestrial-coastal-oceanic gradient: Current status and needs for inter-site comparisons

    Science.gov (United States)

    Troxler, Tiffany G.; Gaiser, Evelyn; Barr, Jordan; Fuentes, Jose D.; Jaffe, Rudolf; Childers, Daniel L.; Collado-Vides, Ligia; Rivera-Monroy, Victor H.; Castañeda-Moya, Edward; Anderson, William; Chambers, Randy; Chen, Meilian; Coronado-Molina, Carlos; Davis, Stephen E.; Engel, Victor C.; Fitz, Carl; Fourqurean, James; Frankovich, Tom; Kominoski, John; Madden, Chris; Malone, Sparkle L.; Oberbauer, Steve F.; Olivas, Paulo; Richards, Jennifer; Saunders, Colin; Schedlbauer, Jessica; Scinto, Leonard J.; Sklar, Fred; Smith, Thomas J.; Smoak, Joseph M.; Starr, Gregory; Twilley, Robert; Whelan, Kevin

    2013-01-01

    Recent studies suggest that coastal ecosystems can bury significantly more C than tropical forests, indicating that continued coastal development and exposure to sea level rise and storms will have global biogeochemical consequences. The Florida Coastal Everglades Long Term Ecological Research (FCE LTER) site provides an excellent subtropical system for examining carbon (C) balance because of its exposure to historical changes in freshwater distribution and sea level rise and its history of significant long-term carbon-cycling studies. FCE LTER scientists used net ecosystem C balance and net ecosystem exchange data to estimate C budgets for riverine mangrove, freshwater marsh, and seagrass meadows, providing insights into the magnitude of C accumulation and lateral aquatic C transport. Rates of net C production in the riverine mangrove forest exceeded those reported for many tropical systems, including terrestrial forests, but there are considerable uncertainties around those estimates due to the high potential for gain and loss of C through aquatic fluxes. C production was approximately balanced between gain and loss in Everglades marshes; however, the contribution of periphyton increases uncertainty in these estimates. Moreover, while the approaches used for these initial estimates were informative, a resolved approach for addressing areas of uncertainty is critically needed for coastal wetland ecosystems. Once resolved, these C balance estimates, in conjunction with an understanding of drivers and key ecosystem feedbacks, can inform cross-system studies of ecosystem response to long-term changes in climate, hydrologic management, and other land use along coastlines

  4. Manure and fertilizer effects on organic and inorganic carbon losses and budget for an irrigated corn field

    Science.gov (United States)

    Little is known about inorganic fertilizer or manure effects on organic carbon (OC) and inorganic C (IC) losses from a furrow irrigated field, particularly in the context of other system C gains or losses. In 2003 and 2004, we measured dissolved organic and inorganic C (DOC, DIC), particulate OC and...

  5. Diurnal and vertical variability of the sensible heat and carbon dioxide budgets in the atmospheric surface layer

    NARCIS (Netherlands)

    Casso-Torralba, P.; Vilà-Guerau de Arellano, J.; Bosveld, F.; Soler, M.R.; Vermeulen, A.; Werner, C.; Moors, E.J.

    2008-01-01

    The diurnal and vertical variability of heat and carbon dioxide (CO2) in the atmospheric surface layer are studied by analyzing measurements from a 213 m tower in Cabauw (Netherlands). Observations of thermodynamic variables and CO2 mixing ratio as well as vertical profiles of the turbulent fluxes

  6. Response of soil respiration and ecosystem carbon budget to vegetation removal in Eucalyptus plantations with contrasting ages.

    Science.gov (United States)

    Wu, Jianping; Liu, Zhanfeng; Huang, Guomin; Chen, Dima; Zhang, Weixin; Shao, Yuanhu; Wan, Songze; Fu, Shenglei

    2014-09-02

    Reforested plantations have substantial effects on terrestrial carbon cycling due to their large coverage area. Although understory plants are important components of reforested plantations, their effects on ecosystem carbon dynamics remain unclear. This study was designed to investigate the effects of vegetation removal/understory removal and tree girdling on soil respiration and ecosystem carbon dynamics in Eucalyptus plantations of South China with contrasting ages (2 and 24 years old). We conducted a field manipulation experiment from 2008 to 2009. Understory removal reduced soil respiration in both plantations, whereas tree girdling decreased soil respiration only in the 2-year-old plantations. The net ecosystem production was approximately three times greater in the 2-year-old plantations (13.4 t C ha(-1) yr(-1)) than in the 24-year-old plantations (4.2 t C h(-1) yr(-1)). The biomass increase of understory plants was 12.6 t ha(-1) yr(-1) in the 2-year-old plantations and 2.9 t ha(-1) yr(-1) in the 24-year-old plantations, accounting for 33.9% nd 14.1% of the net primary production, respectively. Our findings confirm the ecological importance of understory plants in subtropical plantations based on the 2 years of data. These results also indicate that Eucalyptus plantations in China may be an important carbon sink due to the large plantation area.

  7. Modelling the long term impact of climate change on the carbon budget of Lake Simcoe, Ontario using INCA-C.

    Science.gov (United States)

    Oni, S K; Futter, M N; Molot, L A; Dillon, P J

    2012-01-01

    This study presents a process-based model of dissolved organic carbon concentration ([DOC]) in catchments draining into Lake Simcoe, Ontario. INCA-C, the Integrated Catchment model for Carbon, incorporates carbon biogeochemical processes in a terrestrial system with hydrologic flow paths to simulate watershed wide [DOC]. The model successfully simulates present-day inter-annual and seasonal [DOC] dynamics in tributaries draining catchments with mixed or contrasting land cover in the Lake Simcoe watershed (LSW). The sensitivity of INCA-C to soil moisture, hydrologic controls and land uses within a watershed demonstrates its significance as a tool to explore pertinent environmental issues specific to the LSW. Projections of climate change under A1B and A2 SRES scenarios suggest a continuous monotonic increase in [DOC] in surface waters draining into Lake Simcoe. Large variations in seasonal DOC dynamics are predicted to occur during summer with a possibility of displacement of summer [DOC] maxima towards winter and a prolongation of summer [DOC] levels into the autumn. INCA-C also predicts possible increases in dissolved inorganic carbon in some tributaries with rising temperature suggesting increased CO(2) emissions from rivers as climate changes. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Environmental impacts of coastal fish farming; Carbon and Nitrogen budgets for trout farming in Kaldbacksfjord, Faroe Islands

    DEFF Research Database (Denmark)

    Nordi, Gunnvor A; Glud, Ronnie N.; Gaard, Eilif

    2011-01-01

    Flow of organic carbon (OC) and nitrogen through a sea cage trout farm was calculated on the basis of detailed studies of the farming operation, water circulation, OC and nutrient transport and recycling processes in sediment. A third of the OC and nitrogen provided by fish food was incorporated...

  9. An organic carbon budget for coastal Southern California determined by estimates of vertical nutrient flux, net community production and export

    Science.gov (United States)

    Haskell, William Z.; Prokopenko, Maria G.; Hammond, Douglas E.; Stanley, Rachel H. R.; Berelson, William M.; Baronas, J. Jotautas; Fleming, John C.; Aluwihare, Lihini

    2016-10-01

    Organic carbon export and burial in coastal upwelling regions is an important mechanism for oceanic uptake of atmospheric CO2. In order to understand how these complex systems will respond to future climate forcing, further studies of nutrient input, biological production and export are needed. Using a 7Be-based approach, we produced an 18-month record of upwelling velocity estimates at the San Pedro Ocean Time-series (SPOT), Southern California Bight. These upwelling rates and vertical nutrient distributions have been combined to make estimates of potential new production (PNP), which are compared to estimates of net community oxygen production (NOP) made using a one-dimensional, two-box non-steady state model of euphotic zone biological oxygen supersaturation. NOP agrees within uncertainty with PNP, suggesting that upwelling is the dominant mechanism for supplying the ecosystem with new nutrients in the spring season, but negligible in the fall and winter. Combining this data set with estimates of sinking particulate organic carbon (POC) flux from water column 234Th:238U disequilibrium and sediment trap deployments, and an estimate of the ratio of dissolved organic carbon (DOC):POC consumption rates, we construct a simple box model of organic carbon in the upper 200 m of our study site. This box model (with uncertainties of ±50%) suggests that in spring, 28% of net production leaves the euphotic zone as DOC, of this, 12% as horizontal export and 16% via downward mixing. The remaining 72% of net organic carbon export exits as sinking POC, with only 10% of euphotic zone export reaching 200 m. We find the metabolic requirement for the local heterotrophic community below the euphotic zone, but above 200 m, is 105±50 mmol C m-2 d-1, or 80% of net euphotic zone production in spring.

  10. Biodiversity in Benthic Ecology

    DEFF Research Database (Denmark)

    Friberg, Nikolai; Carl, J. D.

    Foreword: This proceeding is based on a set of papers presented at the second Nordic Benthological Meeting held in Silkeborg, November 13-14, 1997. The main theme of the meeting was biodiversity in benthic ecology and the majority of contributions touch on this subject. In addition, the proceeding...

  11. Sensitivity of Holocene atmospheric CO2 and the modern carbon budget to early human land use: analyses with a process-based model

    Directory of Open Access Journals (Sweden)

    F. Joos

    2011-01-01

    Full Text Available A Dynamic Global Vegetation model coupled to a simplified Earth system model is used to simulate the impact of anthropogenic land cover changes (ALCC on Holocene atmospheric CO2 and the contemporary carbon cycle. The model results suggest that early agricultural activities cannot explain the mid to late Holocene CO2 rise of 20 ppm measured on ice cores and that proposed upward revisions of Holocene ALCC imply a smaller contemporary terrestrial carbon sink. A set of illustrative scenarios is applied to test the robustness of these conclusions and to address the large discrepancies between published ALCC reconstructions. Simulated changes in atmospheric CO2 due to ALCC are less than 1 ppm before 1000 AD and 30 ppm at 2004 AD when the HYDE 3.1 ALCC reconstruction is prescribed for the past 12 000 years. Cumulative emissions of 69 GtC at 1850 and 233 GtC at 2004 AD are comparable to earlier estimates. CO2 changes due to ALCC exceed the simulated natural interannual variability only after 1000 AD. To consider evidence that land area used per person was higher before than during early industrialisation, agricultural areas from HYDE 3.1 were increased by a factor of two prior to 1700 AD (scenario H2. For the H2 scenario, the contemporary terrestrial carbon sink required to close the atmospheric CO2 budget is reduced by 0.5 GtC yr−1. Simulated CO2 remains small even in scenarios where average land use per person is increased beyond the range of published estimates. Even extreme assumptions for preindustrial land conversion and high per-capita land use do not result in simulated CO2 emissions that are sufficient to explain the magnitude and the timing of the late Holocene CO2 increase.

  12. Massive Dissociation of Subsurface Gas Hydrates and Collapse of Gas Hydrate Mounds during the LGM in the Eastern Margin of Japan Sea: Evidence from Benthic Forams and U/Th ages of Authigenic Carbonates

    Science.gov (United States)

    Matsumoto, R.; Takeuchi, E.; Sanno, R.

    2008-12-01

    A number of gigantic methane plumes, ca. 600 m high, and massive blocks of gas hydrate, ca. 0.5 m x 1.0 m, have been observed on the Umitaka spur and Joetsu knoll, eastern margin of Japan Sea. Large pockmarks and mounds, ca. 0.5 km in diameter, develop on the spur and knoll. The mounds exhibit rough morphological features characterized by small valleys of 5m wide, steep cliffs, crater-like depressions of 10 m in diameter, and scattered carbonate nodules and crusts of various size and shape with occasional gas hydrate blocks and veins and gas venting. To the contrary, pockmarks are inactive, partly filled by well-stratified mud without any indication of gas venting. 2D and 3D seismic surveys have recognized widely distributed BSRs at around 150 mbsf over the spur and knoll. Seismic profiles delineated deep gas chimney structures below the pockmarks and mounds. Unusual pull-up structures within gas chimneys indicate massive accumulation of gas hydrate. All these findings are likely to suggest that massive hydrate deposits both in gas chimneys at depths and hydrate mounds on the spur and knoll were collapsed and floated up to the sea surface, leaving big holes (= pockmarks) on the seafloor. Quantitative analysis of foraminiferal assemblage has revealed that the well laminated, burrow-free 17 to 22 ka sediments are substantially barren for benthic forams but for unusual species which has been believed to survive under high methane environments. Shells of such a few benthic formas from around 20 ka sediments are anomalously depleted in C-13. U-Th ages of authigenic carbonates of CH4-induced carbonate nodules and crusts are likely to center around 20 ka. Above line of evidences all suggest that gas hydrate system was collapsed and methane fluxes were enhanced during the last glacial maximum (LGM), presumably due to low stand of sea level and pressure release. Broken gas hydrate blocks are expected to float up to the sea surface to supply significant amount of methane to

  13. Isoprene and monoterpene fluxes from Central Amazonian rainforest inferred from tower-based and airborne measurements, and implications on the atmospheric chemistry and the local carbon budget

    Directory of Open Access Journals (Sweden)

    U. Kuhn

    2007-01-01

    . The remarkably high OH concentrations were also supported by results of a simple budget analysis, based on the flux-to-lifetime relationship of isoprene within the CBL. Furthermore, VOC fluxes determined with the airborne MLG approach were only in reasonable agreement with those of the tower-based REA and SLG approaches after correction for chemical decay by OH radicals, applying a best estimate OH concentration of 5.5×106 molecules cm−3. The SCM model calculations support relatively high OH concentration estimates after specifically being constrained by the mixing ratios of chemical constituents observed during the campaign.

    The relevance of the VOC fluxes for the local carbon budget of the tropical rainforest site during the measurements campaign was assessed by comparison with the concurrent CO2 fluxes, estimated by three different methods (eddy correlation, Lagrangian dispersion, and mass budget approach. Depending on the CO2 flux estimate, 1–6% or more of the carbon gained by net ecosystem productivity appeared to be re-emitted through VOC emissions.

  14. Isoprene and monoterpene fluxes from Central Amazonian rainforest inferred from tower-based and airborne measurements, and implications on the atmospheric chemistry and the local carbon budget

    Directory of Open Access Journals (Sweden)

    U. Kuhn

    2007-06-01

    . The remarkably high OH concentrations were also supported by results of a simple budget analysis, based on the flux-to-lifetime relationship of isoprene within the CBL. Furthermore, VOC fluxes determined with the airborne MLG approach were only in reasonable agreement with those of the tower-based REA and SLG approaches after correction for chemical decay by OH radicals, applying a best estimate OH concentration of 5.5×106 molecules cm−3. The SCM model calculations support relatively high OH concentration estimates after specifically being constrained by the mixing ratios of chemical constituents observed during the campaign.

    The relevance of the VOC fluxes for the local carbon budget of the tropical rainforest site during the measurements campaign was assessed by comparison with the concurrent CO2 fluxes, estimated by three different methods (eddy correlation, Lagrangian dispersion, and mass budget approach. Depending on the CO2 flux estimate, 1–6% or more of the carbon gained by net ecosystem productivity appeared to be re-emitted through VOC emissions.

  15. Culturing Fundamentals Used To Design And Execute A Long-Term Multi-stressor Experiment To Assess Impact Of Deoxygenation, Ocean Acidification, And Warming On Benthic Foraminiferal Community Composition, Growth, And Carbonate Yield: Design And Results

    Science.gov (United States)

    Bernhard, J. M.; Wit, J. C.

    2015-12-01

    The geochemistry recorded in carbonate foraminiferal tests (shells) is often used as proxy for past oceanographic events and environments. By understanding past oceanic and climatic conditions, we can better predict future climate scenarios, a relevant ability in these times of global change. The fact that foraminifera are biological entities can be pivotal for understanding their geochemical records. Thus, growing foraminifera under known physicochemical conditions and analyzing the geochemistry of their cultured carbonate can yield insightful perspectives for proxy refinement and development. Because parameters often co-vary in nature, proper proxy calibration can only be done with materials grown in strictly controlled and known environments. This presentation will review the various crucial aspects of foraminiferal maintenance and culturing, especially from the perspective of proxy development. These fundamentals were used to design a long-term multi-stressor experiment with oxygen, pCO2 (pH), and temperature as variables to test the single, double or triple threats of deoxygenation, ocean acidification, and oceanic warming. Results on assemblage composition, survivorship and growth of a continental shelf benthic foraminiferal community will be presented. Although one agglutinated morphospecies grew in each of the five treatments, growth of individual calcareous species was more restricted. Initial results indicate that pCO2 was not the factor that impacted communities most. Supported in part by NSF OCE-1219948.

  16. Highly resolved diurnal trends in natural variability of coral reef carbon budgets, Palau, Western Pacific, using a new automated continuous flow system

    Science.gov (United States)

    Teneva, L. T.; Dunbar, R. B.; Mucciarone, D. A.; Fleischfresser, J. D.

    2011-12-01

    There is growing evidence that ocean acidification (OA) will have significantly detrimental impacts on coral reef calcification and community composition. However, the rates of coral reef response to ocean pH changes and the implications of for ecosystem resilience remain largely unknown. Our ability to make more accurate predictions of OA impacts on coral reefs hinges on an improved capacity for temporal and spatial measurements of coral reef carbon budgets. Here we report on in situ results from a 6 day deployment during April 2011 over a Palauan coral reef. Our experimental approach uses a custom-made automated continuous flow system capable of resolving pH, temperature, and salinity on a 10-second timescale, and Dissolved Inorganic Carbon (DIC) on a 5-minute timescale. In addition, discrete water samples were collected for alkalinity measurements every 3-4 hours in order to capture the essential carbonate variables. We observe higher diurnal amplitude in the DIC and alkalinity signal that is commensurate with greater diurnal tidal range. The highest diurnal alkalinity signal of 100 umol/kg was observed on the first day of the experiment and it progressively decreased throughout the week to 50 umol/kg. A similar trend occurred with DIC, with highest diurnal DIC of 250 umol/kg, decreasing to 100 umol/kg at the end of deployment. Maxima in DIC and alkalinity occurred around 10-11am, and minima occurred near dusk. The diurnal signal in pH ranged 8.0-8.1, with semidiurnal maxima at 2-3am and again~12 hours later. Conversely, minima occurred in mid-morning and again at ~10pm. Our results clearly demonstrate that coral community calcification and photosynthesis affect the surrounding waters' carbon chemistry. In this setting, however, the hydrodynamics - in particular, strong tidal influence -are likely the most significant factor determining the carbon chemistry conditions within the reef community. Highly-resolved natural variability in coral reef metabolism from

  17. Detecting small-scale spatial differences and temporal dynamics of soil organic carbon (SOC) stocks: a comparison between automatic chamber-derived C budgets and repeated soil inventories

    Science.gov (United States)

    Hoffmann, Mathias; Jurisch, Nicole; Garcia Alba, Juana; Albiac Borraz, Elisa; Schmidt, Marten; Huth, Vytas; Rogasik, Helmut; Rieckh, Helene; Verch, Gernot; Sommer, Michael; Augustin, Jürgen

    2017-04-01

    Carbon (C) sequestration in soils plays a key role in the global C cycle. It is therefore crucial to adequately monitor dynamics in soil organic carbon (ΔSOC) stocks when aiming to reveal underlying processes and potential drivers. However, small-scale spatial and temporal changes in SOC stocks, particularly pronounced on arable lands, are hard to assess. The main reasons for this are limitations of the well-established methods. On the one hand, repeated soil inventories, often used in long-term field trials, reveal spatial patterns and trends in ΔSOC but require a longer observation period and a sufficient number of repetitions. On the other hand, eddy covariance measurements of C fluxes towards a complete C budget of the soil-plant-atmosphere system may help to obtain temporal ΔSOC patterns but lack small-scale spatial resolution. To overcome these limitations, this study presents a reliable method to detect both short-term temporal as well as small-scale spatial dynamics of ΔSOC. Therefore, a combination of automatic chamber (AC) measurements of CO2 exchange and empirically modeled aboveground biomass development (NPPshoot) was used. To verify our method, results were compared with ΔSOC observed by soil resampling. AC measurements were performed from 2010 to 2014 under a silage maize/winter fodder rye/sorghum-Sudan grass hybrid/alfalfa crop rotation at a colluvial depression located in the hummocky ground moraine landscape of NE Germany. Widespread in large areas of the formerly glaciated Northern Hemisphere, this depression type is characterized by a variable groundwater level (GWL) and pronounced small-scale spatial heterogeneity in soil properties, such as SOC and nitrogen (Nt). After monitoring the initial stage during 2010, soil erosion was experimentally simulated by incorporating topsoil material from an eroded midslope soil into the plough layer of the colluvial depression. SOC stocks were quantified before and after soil manipulation and at the end

  18. The ORCA West Coast Regional Project - Use of Top-Down Modeling in a Regional Carbon Budget Approach to Estimate Gross Carbon Fluxes for Oregon-California

    Science.gov (United States)

    Goeckede, M.; Turner, D. P.; Law, B. E.

    2007-12-01

    The ORCA project aims at determining the regional carbon balance of Oregon and northern California, with a special focus on the effect of disturbance history and climate variability on carbon sources and sinks. ORCA provides a regional test of the overall NACP strategy by demonstrating bottom-up and model-data fusion approaches to derive carbon balances at subregional to regional scales. The top-down modeling component of ORCA focuses on coupling simple process models for gross primary productivity (GPP), autotrophic (RA) and heterotrophic respiration (RH) with atmospheric transport modeling to interpret measured carbon dioxide concentration data. This approach builds on high-resolution remote sensing products (e.g. Landsat, MODIS) as well as re-analysis meteorological datasets (EDAS-40, DayMet) to drive the models. We couple BRAMS (Brazilian Regional Atmospheric Modeling System) mesoscale modeling to the STILT (Stochastic Time-Inverted Lagrangian Transport) footprint model to identify sources and sinks for carbon that influence observed carbon dioxide concentrations at measurement sites in the ORCA domain. This approach of linking surface fluxes to time series of atmospheric data allows one to extract information from the latter for process model optimization, with the objective of obtaining regionally representative parameter settings for different combinations of ecoregion and land cover type. We present a proof-of-concept of the ORCA top-down modeling approach by comparing modeled to measured carbon dioxide concentration data. This comparison also addresses the uncertainties introduced by different components of this approach. To demonstrate the effect of the improved process model parameterization, the results are compared with regional fluxes derived by the ORCA bottom-up modeling component.

  19. Toward a quantitative and empirical dissolved organic carbon budget for the Gulf of Maine, a semienclosed shelf sea

    Science.gov (United States)

    Balch, William; Huntington, Thomas G.; Aiken, George R.; Drapeau, David; Bowler, Bruce; Lubelczyk, Laura; Butler, Kenna

    2016-01-01

    A time series of organic carbon export from Gulf of Maine (GoM) watersheds was compared to a time series of biological, chemical, bio-optical, and hydrographic properties, measured across the GoM between Yarmouth, NS, Canada, and Portland, ME, U.S. Optical proxies were used to quantify the dissolved organic carbon (DOC) and particulate organic carbon in the GoM. The Load Estimator regression model applied to river discharge data demonstrated that riverine DOC export (and its decadal variance) has increased over the last 80 years. Several extraordinarily wet years (2006–2010) resulted in a massive pulse of chromophoric dissolved organic matter (CDOM; proxy for DOC) into the western GoM along with unidentified optically scattering material (<0.2 μm diameter). A survey of DOC in the GoM and Scotian Shelf showed the strong influence of the Gulf of Saint Lawrence on the DOC that enters the GoM. A deep plume of CDOM-rich water was observed near the coast of Maine which decreased in concentration eastward. The Forel-Ule color scale was derived and compared to the same measurements made in 1912–1913 by Henry Bigelow. Results show that the GoM has yellowed in the last century, particularly in the region of the extension of the Eastern Maine Coastal Current. Time lags between DOC discharge and its appearance in the GoM increased with distance from the river mouths. Algae were also a significant source of DOC but not CDOM. Gulf-wide algal primary production has decreased. Increases in precipitation and DOC discharge to the GoM are predicted over the next century.

  20. Toward a quantitative and empirical dissolved organic carbon budget for the Gulf of Maine, a semienclosed shelf sea

    Science.gov (United States)

    Balch, William; Huntington, Thomas; Aiken, George; Drapeau, David; Bowler, Bruce; Lubelczyk, Laura; Butler, Kenna

    2016-02-01

    A time series of organic carbon export from Gulf of Maine (GoM) watersheds was compared to a time series of biological, chemical, bio-optical, and hydrographic properties, measured across the GoM between Yarmouth, NS, Canada, and Portland, ME, U.S. Optical proxies were used to quantify the dissolved organic carbon (DOC) and particulate organic carbon in the GoM. The Load Estimator regression model applied to river discharge data demonstrated that riverine DOC export (and its decadal variance) has increased over the last 80 years. Several extraordinarily wet years (2006-2010) resulted in a massive pulse of chromophoric dissolved organic matter (CDOM; proxy for DOC) into the western GoM along with unidentified optically scattering material (<0.2 µm diameter). A survey of DOC in the GoM and Scotian Shelf showed the strong influence of the Gulf of Saint Lawrence on the DOC that enters the GoM. A deep plume of CDOM-rich water was observed near the coast of Maine which decreased in concentration eastward. The Forel-Ule color scale was derived and compared to the same measurements made in 1912-1913 by Henry Bigelow. Results show that the GoM has yellowed in the last century, particularly in the region of the extension of the Eastern Maine Coastal Current. Time lags between DOC discharge and its appearance in the GoM increased with distance from the river mouths. Algae were also a significant source of DOC but not CDOM. Gulf-wide algal primary production has decreased. Increases in precipitation and DOC discharge to the GoM are predicted over the next century.

  1. Constraining carbon budgets at a regional scale: fusing forest inventory data with a cohort-based biosphere model

    Science.gov (United States)

    Viskari, T.; Dietze, M.; Desai, A. R.

    2014-12-01

    Forest inventories play an essential role in carbon monitoring and REDD+, however they provide a sparse picture of the carbon cycle at a regional scale. Terrestrial Biosphere Models (TBMs) provide a complete picture of the carbon cycle, but efforts at combining inventory data with models have focused primarily on model calibration and purely model-based regional-scale carbon estimation, which ignore observed disturbances, management, and spatiotemporal variability in forest. Our approach is based on assimilating inventory observations in a size- and age-structured model, the Ecosystem Demography model (ED2). Assumptions of large homogenous areas in ecological models result in loss of details that hinder incorporation of observations. We address how to assimilate inventory data with model predictions in a practical way that is readily extensible to the simultaneous fusion of remote sensing and eddy covariance along with inventories. We updated ED2 predictions on forest growth with Forest Inventory and Analysis program (FIA) data. Data assimilation method was the Ensemble Adjustment Kalman Filter (EAKF) as implemented in Data Assimilation Research Testbed (DART) workflow. The study area is a 1° by 1° grid with the Willow Creek Ameriflux tower in Wisconsin at center. ED2 groups individual trees in cohorts so it captures the landscape-scale heterogeneity. Although this approach speeds up computations, it is not practical to estimate each FIA plot within a chosen area. We classified and averaged data for different plots according to their biomass based on number and size of trees within a plot, focusing on biomass changes over a measurement period. We separately calculated the average diameter at breast height (dbh) and stem density for plants over 5 cm for measured and modeled plots within a biomass class for different Plant Functional Types (PFTs). The results showed EAKF successfully adjusting the predicted changes in biomass according to observations. Variation in

  2. The Effects of Changing Land Use and Climate on the Hydrology and Carbon Budget of Lake Simcoe Watershed, Ontario, Canada

    Science.gov (United States)

    Oni, Stephen Kayode

    The Lake Simcoe watershed (LSW) has experienced significant population growth and is under pressure from development. This has led to land use changes in the watershed in addition to the global climate change that is impacting every region of the world. In this thesis, remote sensing analysis, statistics and process-based modelling approaches were used to better understand dissolved organic carbon (DOC) and runoff dynamics in the changing landscape of LSW. The process-based approach involved the use of the HBV (Hydrologiska Byrans Vattenbalansavdelning) rainfall runoff model and the Integrated Catchment Model for Carbon (INCA-C). Statistical downscaling of the Canadian General Circulation Model (CGCM3) was used to predict the impact of climate change under the IPCC (Intergovernmental Panel on Climate Change) A1B and A2 scenarios. There was a significant land use change in LSW between 1994 and 2009 with a positive monotonic trend in runoff ratio across tributaries. Large increase in runoff ratio without corresponding increase in precipitation suggested that runoff drains more quickly over the land surfaces; an indication of increasing urban-induced impervious surfaces. However, there was a significant increase in air temperature (MK = 0.315; ppredicted an increase in air temperature by a maximum of 1.4°C by 2050 and up to 3.5°C by 2100 relative to the baseline period (1960-2000). HBV predicted a largest variability in the spring and winter season's runoff regimes (2020-2050) under both A1B and A2 scenarios. A 5% increase in DOC concentration and a 6% increase in flux were observed between period 1 (1994-1997) and period 2 (2007-2009). The observed increases were driven by spring (20%) and summer (26%). INCA-C predicted a positive monotonic increase in long-term DOC concentrations (2020-2100) in surface waters draining into Lake Simcoe under both scenarios with the largest seasonal variations in DOC concentrations predicted to occur in the summer months. This

  3. Environmental impacts of coastal fish farming; Carbon and Nitrogen budgets for trout farming in Kaldbacksfjord, Faroe Islands

    DEFF Research Database (Denmark)

    Nordi, Gunnvor A; Glud, Ronnie N.; Gaard, Eilif

    2011-01-01

    Flow of organic carbon (OC) and nitrogen through a sea cage trout farm was calculated on the basis of detailed studies of the farming operation, water circulation, OC and nutrient transport and recycling processes in sediment. A third of the OC and nitrogen provided by fish food was incorporated......% of nitrogen derived from fish food settled on the seabed, where it was either mineralized or accumulated in the sediment. Based on transect measurements of diagenetic activity, the farm footprint was found to cover an area similar to 10 times the farm area. OC mineralization in the sediment increased linearly...

  4. Potential Impact of Microbial Activity on the Oxidant Capacity and the Organic Carbon Budget in Clouds (Invited)

    Science.gov (United States)

    Delort, A.

    2013-12-01

    Within cloud water, microorganisms are metabolically active; so they are suspected to contribute to atmospheric chemistry. This paper is focused on the interactions between microorganisms and Reactive Oxygenated Species present in cloud water since these chemical compounds are driving the oxidant capacity of the cloud system. For this, real cloud waters with contrasting features (marine, continental, urban) were sampled at the puy de Dôme mountain (France). They exhibit high microbial biodiversity and complex chemical composition. These media were incubated in the dark and subjected to UV-light radiation in specifically designed photo-bio-reactors. The concentrations of hydrogen peroxide (H2O2), organic compounds and the ATP/ADP ratio were monitored during the incubation period. Microorganisms remained metabolically active in the presence of hydroxyl radicals photo-produced from H2O2. This oxidant and major carbon compounds (formaldehyde and carboxylic acids) were biodegraded by the endogenous microflora. This work suggests that microorganisms could play a double role in atmospheric chemistry: first, they could directly metabolize organic carbon species; second they could reduce the available source of radicals due to their oxidative metabolism. Consequently, molecules such as H2O2 would be no longer available for photochemical or other chemical reactions, decreasing the cloud oxidant capacity.

  5. Where have all the carbonates gone? A model comparison of calcium carbonate budgets before and after the 1982 1983 El Nino at Uva Island in the eastern Pacific

    Science.gov (United States)

    Eakin, C. M.

    1996-06-01

    El Nifio related coral mortality and a subsequent increase in crustose coralline algae and sea urchins have resulted in profound changes to the coral reef ecosystem at Uva Island, Panama (Pacific coast). New data and a model are presented that analyze the CaCO3 budget of the reef. The model accounts for production by corals and coralline algae, erosion by Diadema, infauna, fish and other motile organisms, and the retention of sediments as a function of size. The 2.5 ha reef is currently eroding at an average rate of 4,800 kg/y or -0.19 kg/m2/y but there is tremendous variation among reef zones. While deposition in other zones range from +0.1 to 0.4 kg/m2/y, erosion of the seaward reef base averages about -3.65 kg/m2/y. The damselfish/algal lawn symbiosis protects portions of the reef framework, reducing net losses there by 2,000 kg/y (up to 0.33 kg/m2/y). Before the 1982-1983 El Niño, the overall reef was depositional. At that time, estimated production exceeded erosion in most zones, resulting in a net deposition of approximately 8,600 kg/y or 0.34 kg/m2/y.

  6. Effects of an oil spill on benthic community production and respiration on subtropical intertidal sandflats.

    Science.gov (United States)

    Lee, Li-Hua; Lin, Hsing-Juh

    2013-08-15

    This study determined effects of an oil spill on subtropical benthic community production and respiration by monitoring CO2 fluxes in benthic chambers on intertidal sandflats during emersion before and after an accidental spill. The oil spill decreased sediment chlorophyll a concentrations, altered benthic macrofaunal community, and affected ecological functioning by suppressing or even stopping microalgal production, increasing bacterial respiration, and causing a shift from an autotrophic system to a heterotrophic system. Effects of the oil spill on the macrofauna were more severe than on benthic microalgae, and affected sedentary infauna more than motile epifauna. Despite the oil spill's impact on the benthic community and carbon metabolism, the affected area appeared to return to normal in about 23 days. Our results suggest that the prompt response of benthic metabolism to exposure to petroleum hydrocarbons can serve as a useful indicator of the impact of an oil spill.

  7. Multi-scale geospatial agroecosystem modeling: a case study on the influence of soil data resolution on carbon budget estimates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuesong; Sahajpal, Ritvik; Manowitz, D.; Zhao, Kaiguang; LeDuc, Stephen D.; Xu, Min; Xiong, Wei; Zhang, Aiping; Izaurralde, Roberto C.; Thomson, Allison M.; West, Tristram O.; Post, W. M.

    2014-05-01

    The development of effective measures to stabilize atmospheric CO2 concentration and mitigate negative impacts of climate change requires accurate quantification of the spatial variation and magnitude of the terrestrial carbon (C) flux. However, the spatial pattern and strength of terrestrial C sinks and sources remain uncertain. In this study, we designed a spatially-explicit agroecosystem modeling system by integrating the Environmental Policy Integrated Climate (EPIC) model with multiple sources of geospatial and surveyed datasets (including crop type map, elevation, climate forcing, fertilizer application, tillage type and distribution, and crop planting and harvesting date), and applied it to examine the sensitivity of cropland C flux simulations to two widely used soil databases (i.e. State Soil Geographic-STATSGO of a scale of 1:250,000 and Soil Survey Geographic-SSURGO of a scale of 1:24,000) in Iowa, USA. To efficiently execute numerous EPIC runs resulting from the use of high resolution spatial data (56m), we developed a parallelized version of EPIC. Both STATSGO and SSURGO led to similar simulations of crop yields and Net Ecosystem Production (NEP) estimates at the State level. However, substantial differences were observed at the county and sub-county (grid) levels. In general, the fine resolution SSURGO data outperformed the coarse resolution STATSGO data for county-scale crop-yield simulation, and within STATSGO, the area-weighted approach provided more accurate results. Further analysis showed that spatial distribution and magnitude of simulated NEP were more sensitive to the resolution difference between SSURGO and STATSGO at the county or grid scale. For over 60% of the cropland areas in Iowa, the deviations between STATSGO- and SSURGO-derived NEP were larger than 1MgCha(-1)yr(-1), or about half of the average cropland NEP, highlighting the significant uncertainty in spatial distribution and magnitude of simulated C fluxes resulting from

  8. The carbon budget of Pinus radiata plantations in south-western Australia under four climate change scenarios.

    Science.gov (United States)

    Simioni, Guillaume; Ritson, Peter; Kirschbaum, Miko U F; McGrath, John; Dumbrell, Ian; Copeland, Beth

    2009-09-01

    We conducted a comprehensive modelling study to estimate future stem wood production and net ecosystem production (NEP) of Pinus radiata D. Don plantations in south-western Australia, a region that is predicted to undergo severe rainfall reduction in future decades. The process-based model CenW was applied to four locations where it had previously been tested. Climate change scenarios under four emission scenarios for the period from 2005 to 2066 were considered, in addition to simulations under the current climate. Results showed that stem wood production and NEP were little affected by moderate climate change. However, under the most pessimistic climate change scenario (Special Report on Emission Scenarios A2), stem wood production and NEP decreased strongly. These results could be explained by the trade-off between the positive effect of rising atmospheric CO(2) on plant water use efficiency and the negative effects of decreasing rainfall and increasing temperatures. Because changes in heterotrophic respiration (R(H)) lagged behind changes in plant growth, and because R(H) rates were increased by higher temperatures, NEP was more negatively affected than stem wood production. Stem wood production and NEP also strongly interacted with location, with the site currently having the wettest climate being least affected by climatic change. These results suggest that realistic predictions of forest production and carbon sequestration potential in the context of climate change require (1) the use of modelling tools that describe the important feedbacks between environmental variables, plant physiology and soil organic matter decomposition, (2) consideration of a range of climate change scenarios and (3) simulations that account for a gradual climate change to capture transient effects.

  9. Estimation of Carbon Budgets for Croplands by Combining High Resolution Remote Sensing Data with a Crop Model and Validation Ground Data

    Science.gov (United States)

    Mangiarotti, S.; Veloso, A.; Ceschia, E.; Tallec, T.; Dejoux, J. F.

    2015-12-01

    Croplands occupy large areas of Earth's land surface playing a key role in the terrestrial carbon cycle. Hence, it is essential to quantify and analyze the carbon fluxes from those agro-ecosystems, since they contribute to climate change and are impacted by the environmental conditions. In this study we propose a regional modeling approach that combines high spatial and temporal resolutions (HSTR) optical remote sensing data with a crop model and a large set of in-situ measurements for model calibration and validation. The study area is located in southwest France and the model that we evaluate, called SAFY-CO2, is a semi-empirical one based on the Monteith's light-use efficiency theory and adapted for simulating the components of the net ecosystem CO2 fluxes (NEE) and of the annual net ecosystem carbon budgets (NECB) at a daily time step. The approach is based on the assimilation of satellite-derived green area index (GAI) maps for calibrating a number of the SAFY-CO2 parameters linked to crop phenology. HSTR data from the Formosat-2 and SPOT satellites were used to produce the GAI maps. The experimental data set includes eddy covariance measurements of net CO2 fluxes from two experimental sites and partitioned into gross primary production (GPP) and ecosystem respiration (Reco). It also includes measurements of GAI, biomass and yield between 2005 and 2011, focusing on the winter wheat crop. The results showed that the SAFY-CO2 model correctly reproduced the biomass production, its dynamic and the yield (relative errors about 24%) in contrasted climatic, environmental and management conditions. The net CO2 flux components estimated with the model were overall in agreement with the ground data, presenting good correlations (R² about 0.93 for GPP, 0.77 for Reco and 0.86 for NEE). The evaluation of the modelled NECB for the different site-years highlighted the importance of having accurate estimates of each component of the NECB. Future works aim at considering

  10. A carbon budget for the Amundsen Sea Polynya, Antarctica: Estimating net community production and export in a highly productive polar ecosystem

    Directory of Open Access Journals (Sweden)

    PL Yager

    2016-12-01

    Full Text Available Abstract Polynyas, or recurring areas of seasonally open water surrounded by sea ice, are foci for energy and material transfer between the atmosphere and the polar ocean. They are also climate sensitive, with both sea ice extent and glacial melt influencing their productivity. The Amundsen Sea Polynya (ASP is the greenest polynya in the Southern Ocean, with summertime chlorophyll a concentrations exceeding 20 µg L−1. During the Amundsen Sea Polynya International Research Expedition (ASPIRE in austral summer 2010–11, we aimed to determine the fate of this high algal productivity. We collected water column profiles for total dissolved inorganic carbon (DIC and nutrients, particulate and dissolved organic matter, chlorophyll a, mesozooplankton, and microbial biomass to make a carbon budget for this ecosystem. We also measured primary and secondary production, community respiration rates, vertical particle flux and fecal pellet production and grazing. With observations arranged along a gradient of increasing integrated dissolved inorganic nitrogen drawdown (ΔDIN; 0.027–0.74 mol N m−2, changes in DIC in the upper water column (ranging from 0.2 to 4.7 mol C m−2 and gas exchange (0–1.7 mol C m−2 were combined to estimate early season net community production (sNCP; 0.2–5.9 mol C m−2 and then compared to organic matter inventories to estimate export. From a phytoplankton bloom dominated by Phaeocystis antarctica, a high fraction (up to ∼60% of sNCP was exported to sub-euphotic depths. Microbial respiration remineralized much of this export in the mid waters. Comparisons to short-term (2–3 days drifting traps and a year-long moored sediment trap capturing the downward flux confirmed that a relatively high fraction (3–6% of the export from ∼100 m made it through the mid waters to depth. We discuss the climate-sensitive nature of these carbon fluxes, in light of the changing sea ice cover and melting ice sheets in the region.

  11. Methane-carbon flow into the benthic food web at cold seeps--a case study from the Costa Rica subduction zone.

    Directory of Open Access Journals (Sweden)

    Helge Niemann

    Full Text Available Cold seep ecosystems can support enormous biomasses of free-living and symbiotic chemoautotrophic organisms that get their energy from the oxidation of methane or sulfide. Most of this biomass derives from animals that are associated with bacterial symbionts, which are able to metabolize the chemical resources provided by the seeping fluids. Often these systems also harbor dense accumulations of non-symbiotic megafauna, which can be relevant in exporting chemosynthetically fixed carbon from seeps to the surrounding deep sea. Here we investigated the carbon sources of lithodid crabs (Paralomis sp. feeding on thiotrophic bacterial mats at an active mud volcano at the Costa Rica subduction zone. To evaluate the dietary carbon source of the crabs, we compared the microbial community in stomach contents with surface sediments covered by microbial mats. The stomach content analyses revealed a dominance of epsilonproteobacterial 16S rRNA gene sequences related to the free-living and epibiotic sulfur oxidiser Sulfurovum sp. We also found Sulfurovum sp. as well as members of the genera Arcobacter and Sulfurimonas in mat-covered surface sediments where Epsilonproteobacteria were highly abundant constituting 10% of total cells. Furthermore, we detected substantial amounts of bacterial fatty acids such as i-C15∶0 and C17∶1ω6c with stable carbon isotope compositions as low as -53‰ in the stomach and muscle tissue. These results indicate that the white microbial mats at Mound 12 are comprised of Epsilonproteobacteria and that microbial mat-derived carbon provides an important contribution to the crab's nutrition. In addition, our lipid analyses also suggest that the crabs feed on other (13C-depleted organic matter sources, possibly symbiotic megafauna as well as on photosynthetic carbon sources such as sedimentary detritus.

  12. Methane-Carbon Flow into the Benthic Food Web at Cold Seeps – A Case Study from the Costa Rica Subduction Zone

    Science.gov (United States)

    Niemann, Helge; Linke, Peter; Knittel, Katrin; MacPherson, Enrique; Boetius, Antje; Brückmann, Warner; Larvik, Gaute; Wallmann, Klaus; Schacht, Ulrike; Omoregie, Enoma; Hilton, David; Brown, Kevin; Rehder, Gregor

    2013-01-01

    Cold seep ecosystems can support enormous biomasses of free-living and symbiotic chemoautotrophic organisms that get their energy from the oxidation of methane or sulfide. Most of this biomass derives from animals that are associated with bacterial symbionts, which are able to metabolize the chemical resources provided by the seeping fluids. Often these systems also harbor dense accumulations of non-symbiotic megafauna, which can be relevant in exporting chemosynthetically fixed carbon from seeps to the surrounding deep sea. Here we investigated the carbon sources of lithodid crabs (Paralomis sp.) feeding on thiotrophic bacterial mats at an active mud volcano at the Costa Rica subduction zone. To evaluate the dietary carbon source of the crabs, we compared the microbial community in stomach contents with surface sediments covered by microbial mats. The stomach content analyses revealed a dominance of epsilonproteobacterial 16S rRNA gene sequences related to the free-living and epibiotic sulfur oxidiser Sulfurovum sp. We also found Sulfurovum sp. as well as members of the genera Arcobacter and Sulfurimonas in mat-covered surface sediments where Epsilonproteobacteria were highly abundant constituting 10% of total cells. Furthermore, we detected substantial amounts of bacterial fatty acids such as i-C15∶0 and C17∶1ω6c with stable carbon isotope compositions as low as −53‰ in the stomach and muscle tissue. These results indicate that the white microbial mats at Mound 12 are comprised of Epsilonproteobacteria and that microbial mat-derived carbon provides an important contribution to the crab's nutrition. In addition, our lipid analyses also suggest that the crabs feed on other 13C-depleted organic matter sources, possibly symbiotic megafauna as well as on photosynthetic carbon sources such as sedimentary detritus. PMID:24116017

  13. Methane-carbon flow into the benthic food web at cold seeps--a case study from the Costa Rica subduction zone.

    Science.gov (United States)

    Niemann, Helge; Linke, Peter; Knittel, Katrin; MacPherson, Enrique; Boetius, Antje; Brückmann, Warner; Larvik, Gaute; Wallmann, Klaus; Schacht, Ulrike; Omoregie, Enoma; Hilton, David; Brown, Kevin; Rehder, Gregor

    2013-01-01

    Cold seep ecosystems can support enormous biomasses of free-living and symbiotic chemoautotrophic organisms that get their energy from the oxidation of methane or sulfide. Most of this biomass derives from animals that are associated with bacterial symbionts, which are able to metabolize the chemical resources provided by the seeping fluids. Often these systems also harbor dense accumulations of non-symbiotic megafauna, which can be relevant in exporting chemosynthetically fixed carbon from seeps to the surrounding deep sea. Here we investigated the carbon sources of lithodid crabs (Paralomis sp.) feeding on thiotrophic bacterial mats at an active mud volcano at the Costa Rica subduction zone. To evaluate the dietary carbon source of the crabs, we compared the microbial community in stomach contents with surface sediments covered by microbial mats. The stomach content analyses revealed a dominance of epsilonproteobacterial 16S rRNA gene sequences related to the free-living and epibiotic sulfur oxidiser Sulfurovum sp. We also found Sulfurovum sp. as well as members of the genera Arcobacter and Sulfurimonas in mat-covered surface sediments where Epsilonproteobacteria were highly abundant constituting 10% of total cells. Furthermore, we detected substantial amounts of bacterial fatty acids such as i-C15∶0 and C17∶1ω6c with stable carbon isotope compositions as low as -53‰ in the stomach and muscle tissue. These results indicate that the white microbial mats at Mound 12 are comprised of Epsilonproteobacteria and that microbial mat-derived carbon provides an important contribution to the crab's nutrition. In addition, our lipid analyses also suggest that the crabs feed on other (13)C-depleted organic matter sources, possibly symbiotic megafauna as well as on photosynthetic carbon sources such as sedimentary detritus.

  14. Effect of nutrient availability on carbon and nitrogen incorporation and flows through benthic algae and bacteria in near-shore sandy sediment

    NARCIS (Netherlands)

    Cook, P.; Veuger, B.; Böer, S.; Middelburg, J.J.

    2007-01-01

    Carbon and nitrogen uptake in a microbial community comprising bacteria and microalgae in a sandy marine sediment under nutrient-limited and -replete conditions was studied using a mesocosm approach. After 2 wk of incubation, a pulse of H13CO3– and 15NH4+ was added to the mesocosms, and subsequent

  15. Temporal Variations of the Atmospheric CO2 Concentration and Its Carbon Isotope Ratio at Ny-Ålesund, Svalbard and Estimation of Global Carbon Budget

    Science.gov (United States)

    Goto, D.; Morimoto, S.; Ishidoya, S.; Aoki, S.; Nakazawa, T.

    2016-12-01

    Long-term measurements of the atmospheric CO2 concentration and its carbon isotope ratio (δ13C) are useful for partitioning anthropogenic CO2 into the terrestrial biosphere and the ocean, if the carbon isotopic disequilibrium flux (so-called isoflux), combining terrestrial and oceanic contributions, is quantified. For a better understanding of the global carbon cycle, we have carried out the systematic observation of the atmospheric CO2 concentration and δ13C at Ny-Ålesund, Svalbard (78.93°N, 11.83°E) since 1991. Air samples were collected into stainless-steel flasks at the Japanese observatory in Ny-Ålesund, once a week and sent to NIPR every two months. CO2 concentrations of the air samples were determined by using a NDIR analyzer, and CO2 samples extracted cryogenically from the remaining air in the flasks were analyzed for δ13C using a mass spectrometer. Analytical precisions for CO2 and δ13C were 0.01 ppm and 0.02 ‰, respectively. The CO2 concentration shows a clear seasonal cycle with peak-to-peak amplitude of about 17 ppm, which reaches a maximum in late April to early May and a minimum in late August, superimposed on a secular increase with an average rate of 2.0 ppm/yr for the period of 1996-2013. On the other hand, the δ13C decreases secularly at an average rate of -0.018 ‰/yr, and varies seasonally in opposite phase with the CO2 concentration. By analyzing the CO2 concentration and δ13C using the isoflux calculated with a box-diffusion model, the terrestrial biospheric and oceanic CO2 sinks are estimated to be 1.5 ± 0.3 and 2.4 ± 0.4 GtC/yr, respectively, for the 13-year period (2001-2013). On the other hand, the secular trends of the atmospheric δ(O2/N2) and CO2 concentration at Ny-Ålesund (Ishidoya et al., 2012) yield the respective sink values of 1.7 ± 0.8 and 2.2 ± 0.7 GtC/yr for the same period. The estimates from the two methods are in good agreement with each other.

  16. Sources of Black Carbon Aerosols in South Asia and Surrounding Regions During the Integrated Campaign for Aerosols, Gases and Radiation Budget (ICARB)

    Science.gov (United States)

    Kumar, R.; Barth, M. C.; Nair, V. S.; Pfister, G.; Babu, S. S.; Satheesh, S. K.; Krishnamoorthy, K.; Carmichael, G. R.

    2014-12-01

    The dominant sources of black carbon (BC) in South Asia and surrounding regions are inferred during March-May 2006 (Integrated Campaign for Aerosols, Gases and Radiation Budget (ICARB)) by introducing BC tracers in the Weather Research and Forecasting Model coupled with Chemistry. Model results show that ICARB measurements were fairly well representative of the Arabian Sea and the Bay of Bengal during the pre-monsoon season. The model reproduced well the magnitude, temporal and spatial variability of BC concentrations observed during the ICARB ship-cruise. Average and standard deviation (representing the spatial and temporal variability) in observed and modeled BC mass concentrations along the ship-track are estimated as 755±734 ng m-3 and 732±913 ng m-3 respectively, where the standard deviation represents the spatial and temporal variability in the region. Average modeled values at most of the inland stations were also found to fall within the range of observed values. Results show that anthropogenic and biomass burning emissions, respectively, accounted for 70% and 28% of the BC mass concentration in South Asia. BC emissions from residential (49%) and industrial (37%) sectors appear to be the major anthropogenic sources, except in the Himalayas where vehicular emissions dominate. We find that, while all parts of continental India contributed to anthropogenic BC over Bay of Bengal, contribution over the Arabian Sea came mostly from southern Peninsula. We also show that long-range transport of anthropogenic emissions contribute up to 30% of BC concentrations in western and eastern India, suggesting that it is important to consider non-local sources along with the local emissions while designing strategies for mitigating BC emissions.

  17. Benthic foraminiferal Mn / Ca ratios reflect microhabitat preferences

    NARCIS (Netherlands)

    Koho, K.A.; de Nooijer, L.J.; Fontanier, C.; Toyofuku, T.; Oguri, K.; Kitazato, H.; Reichart, G.-J.

    2017-01-01

    The Mn / Ca of calcium carbonate tests of living (rose-Bengal-stained) benthic foraminifera (Elphidium batialis, Uvigerina spp., Bolivina spissa, Nonionellina labradorica and Chilostomellina fimbriata) were determined in relation to pore water manganese (Mn) concentrations for the first time along a

  18. Automated Budget System

    Data.gov (United States)

    Department of Transportation — The Automated Budget System (ABS) automates management and planning of the Mike Monroney Aeronautical Center (MMAC) budget by providing enhanced capability to plan,...

  19. Benthic fluxes of dissolved organic nitrogen in the Lower St. Lawrence Estuary and implications for selective organic matter degradation

    Directory of Open Access Journals (Sweden)

    M. Alkhatib

    2013-05-01

    Full Text Available The distribution of dissolved organic nitrogen (DON and carbon (DOC in sediment pore waters was determined at nine locations along the St. Lawrence Estuary and in the Gulf of St. Lawrence. The study area is characterized by gradients in the sedimentary particulate organic matter (POM reactivity, bottom water oxygen concentrations, as well as benthic respiration rates. Based on pore water profiles we estimated the benthic diffusive fluxes of DON and DOC. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 μmol m−2 d−1. DON fluxes were positively correlated with sedimentary POM reactivity and sediment oxygen exposure time (OET, suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30% to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange. This result is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. The ratio of the DON to nitrate flux increased from 0.6 in the Lower Estuary to 1.5 in the Gulf. In contrast to DON, DOC fluxes did not show any significant spatial variation along the Laurentian Channel (LC between the Estuary and the Gulf (2100 ± 100μmol m−2 d−1, suggesting that production and consumption of labile DOC components proceed at similar rates, irrespective of the overall benthic characteristics and the reactivity of POM. As a consequence, the molar C/N ratio of dissolved organic matter (DOM in pore water and the overlying bottom water varied significantly along the transect, with lowest C/N in the Lower Estuary (5–6 and highest C/N (> 10 in the Gulf. We observed large differences between the C/N of pore water DOM with respect to POM, and the degree of

  20. 低碳经济背景下经济型酒店绿色管理探析%On Green Management of Budget Hotel in the Low-carbon Economy

    Institute of Scientific and Technical Information of China (English)

    谢宝田

    2013-01-01

    在全球低碳经济时代背景下,酒店业的绿色管理理念应运而生。经济型酒店作为酒店业的重要组成部分,其经营理念与绿色管理有异曲同工之处,具有推行绿色管理的独特优势,但是在观念、制度、产品、服务方面仍存在不容忽视的问题。完善和优化经济型酒店的绿色管理,不仅能顺应低碳经济时代发展的要求,还可以提高经济型酒店的整体竞争力。%In the low-carbon economy, green management concept has emerged in hotel industry.Budget hotel, an important part of the hotel industry, has the unique advantage of green management , but there are some problems in the concept, system, product and service.Improving and optimizing the green management of budget hotel , can not only a-dapt to the development of low -carbon economy, but also improve the overall competitiveness of the budget hotel.

  1. Differential processing of anthropogenic carbon and nitrogen in benthic food webs of A Coruña (NW Spain) traced by stable isotopes

    OpenAIRE

    Bode, A.; Fernández, C.; Mompeán, C.; Parra, S; Rozada, F.; Valencia-Vila, J.; Viana, I.G.

    2013-01-01

    proyectos ANILE (CTM2009- 08396 and CTM2010-08804-E) del Plan Nacional de I+D+i y RADIALES del Instituto Español de Oceanografía (IEO). C.M. e I.G.V. disfrutaron de contratos FPI del IEO y del Ministerio de Economía y Competividad respectivamente. In this study the effect of inputs of organic matter and anthropogenic nitrogen at small spatial scales were investigated in the benthos of the Ria of A Coruña (NW Spain) using stable carbon and nitrogen isotopes. This ria is characteri...

  2. Cold-water coral reefs and adjacent sponge grounds: Hotspots of benthic respiration and organic carbon cycling in the deep sea

    Directory of Open Access Journals (Sweden)

    Cecile eCathalot

    2015-06-01

    Full Text Available Cold-water coral reefs and adjacent sponge grounds are distributed widely in the deep ocean, where only a small fraction of the surface productivity reaches the seafloor as detritus. It remains elusive how these hotspots of biodiversity can thrive in such a food-limited environment, as data on energy flow and organic carbon utilization are critically lacking. Here we report in situ community respiration rates for cold-water coral and sponge ecosystems obtained by the non-invasive aquatic Eddy Correlation technique. Oxygen uptake rates over coral reefs and adjacent sponge grounds in the Træna Coral Field (Norway were 9-20 times higher than those of the surrounding soft sediments. These high respiration rates indicate strong organic matter consumption, and hence suggest a local focusing onto these ecosystems of the downward flux of organic matter that is exported from the surface ocean. Overall, our results show that coral reefs and adjacent sponge grounds are hotspots of carbon processing in the food-limited deep ocean, and that these deep-sea ecosystems play a more prominent role in marine biogeochemical cycles than previously recognized.

  3. Dissolved organic carbon (DOC) and select aldehydes in cloud and fog water: the role of the aqueous phase in impacting trace gas budgets

    Science.gov (United States)

    Ervens, B.; Wang, Y.; Eagar, J.; Leaitch, W. R.; Macdonald, A. M.; Valsaraj, K. T.; Herckes, P.

    2013-05-01

    Cloud and fog droplets efficiently scavenge and process water-soluble compounds and, thus, modify the chemical composition of the gas and particle phases. The concentrations of dissolved organic carbon (DOC) in the aqueous phase reach concentrations on the order of ~ 10 mgC L-1 which is typically on the same order of magnitude as the sum of inorganic anions. Aldehydes and carboxylic acids typically comprise a large fraction of DOC because of their high solubility. The dissolution of species in the aqueous phase can lead to (i) the removal of species from the gas phase preventing their processing by gas phase reactions (e.g., photolysis of aldehydes) and (ii) the formation of unique products that do not have any efficient gas phase sources (e.g., dicarboxylic acids). We present measurements of DOC and select aldehydes in fog water at high elevation and intercepted clouds at a biogenically-impacted location (Whistler, Canada) and in fog water in a more polluted area (Davis, CA). Concentrations of formaldehyde, glyoxal and methylglyoxal were in the micromolar range and comprised ≤ 2% each individually of the DOC. Comparison of the DOC and aldehyde concentrations to those at other locations shows good agreement and reveals highest levels for both in anthropogenically impacted regions. Based on this overview, we conclude that the fraction of organic carbon (dissolved and insoluble inclusions) in the aqueous phase of clouds or fogs, respectively, comprises 2-~ 40% of total organic carbon. Higher values are observed to be associated with aged air masses where organics are expected to be more highly oxidised and, thus, more soluble. Accordingly, the aqueous/gas partitioning ratio expressed here as an effective Henry's law constant for DOC (KH*DOC) increases by an order of magnitude from 7 × 103 M atm-1 to 7 × 104 M atm-1 during the ageing of air masses. The measurements are accompanied by photochemical box model simulations. These simulations are used to contrast two

  4. Dissolved organic carbon (DOC and select aldehydes in cloud and fog water: the role of the aqueous phase in impacting trace gas budgets

    Directory of Open Access Journals (Sweden)

    B. Ervens

    2013-05-01

    Full Text Available Cloud and fog droplets efficiently scavenge and process water-soluble compounds and, thus, modify the chemical composition of the gas and particle phases. The concentrations of dissolved organic carbon (DOC in the aqueous phase reach concentrations on the order of ~ 10 mgC L−1 which is typically on the same order of magnitude as the sum of inorganic anions. Aldehydes and carboxylic acids typically comprise a large fraction of DOC because of their high solubility. The dissolution of species in the aqueous phase can lead to (i the removal of species from the gas phase preventing their processing by gas phase reactions (e.g., photolysis of aldehydes and (ii the formation of unique products that do not have any efficient gas phase sources (e.g., dicarboxylic acids. We present measurements of DOC and select aldehydes in fog water at high elevation and intercepted clouds at a biogenically-impacted location (Whistler, Canada and in fog water in a more polluted area (Davis, CA. Concentrations of formaldehyde, glyoxal and methylglyoxal were in the micromolar range and comprised ≤ 2% each individually of the DOC. Comparison of the DOC and aldehyde concentrations to those at other locations shows good agreement and reveals highest levels for both in anthropogenically impacted regions. Based on this overview, we conclude that the fraction of organic carbon (dissolved and insoluble inclusions in the aqueous phase of clouds or fogs, respectively, comprises 2–~ 40% of total organic carbon. Higher values are observed to be associated with aged air masses where organics are expected to be more highly oxidised and, thus, more soluble. Accordingly, the aqueous/gas partitioning ratio expressed here as an effective Henry's law constant for DOC (KH*DOC increases by an order of magnitude from 7 × 103 M atm−1 to 7 × 104 M atm−1 during the ageing of air masses. The measurements are accompanied by photochemical box model simulations. These simulations are

  5. Dissolved organic carbon (DOC and select aldehydes in cloud and fog water: the role of the aqueous phase in impacting trace gas budgets

    Directory of Open Access Journals (Sweden)

    B. Ervens

    2012-12-01

    Full Text Available Cloud and fog droplets efficiently scavenge and process water-soluble compounds and thus modify the chemical composition of the gas and particle phases. The concentrations of dissolved organic carbon (DOC in the aqueous phase reach concentrations on the order of ~10 mg C L−1 which is typically on the same order of magnitude as the sum of inorganic anions. Aldehydes and carboxylic acids typically comprise a large fraction of DOC because of their high solubility. The dissolution of species in the aqueous phase can lead to (i the removal of species from the gas phase preventing their processing by gas phase reactions (e.g. photolysis of aldehydes and (ii the formation of unique products that do not have any efficient gas phase sources (e.g. dicarboxylic acids.

    We present measurements of DOC and select aldehydes in fog water at high elevation and intercepted clouds in a biogenically-impacted location (Whistler, Canada and in fog water in a more polluted area (Davis, CA. Concentrations of formaldehyde, glyoxal and methylglyoxal were in the micromolar range and comprised ≤2% each individually of the DOC. Comparison of the DOC and aldehyde concentrations to those at other locations shows good agreement and reveals highest levels for both in anthropogenically impacted regions. Based on this overview, we conclude that the fraction of organic carbon (dissolved and insoluble inclusions in the aqueous phase comprises 1–~40% of total organic carbon. Higher values are observed to be associated with aged air masses where organics are expected to be more highly oxidized and thus more soluble. Accordingly, the aqueous/gas partitioning ratio expressed here as an effective Henry's law constant for DOC (KH*DOC increases by an order of magnitude from 7×103 M atm−1 to 7×104 M atm−1 during the ageing of air masses.

    The measurements are accompanied by

  6. American Samoa ESI: BENTHIC (Benthic Marine Habitat Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for benthic habitats in American Samoa. Vector polygons in this data set represent the distribution of...

  7. A Defense Budget Primer

    Science.gov (United States)

    1998-12-09

    budget practices. See Appendix D for the actual timetable of congressional action on the FY1999 budget.65 See James V. Saturno , The Appropriations...details, see James V. Saturno , The Appropriations Process and the Congressional69 Budget Act, CRS Report 97-947. Table 6. Milestone Votes on the Defense...James V. Saturno , The74 Appropriations Process and the Congressional Budget Act, CRS Report 97-947. The Budget Enforcement Act of 1990 and subsequent

  8. National Benthic Infaunal Database (NBID)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NBID is a quantitative database on abundances of individual benthic species by sample and study region, along with other synoptically measured environmental...

  9. NEPR Benthic Habitat Map 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This benthic habitat map was created from a semi-automated habitat mapping process, using a combination of bathymetry, satellite imagery, aerial imagery and...

  10. Differential processing of anthropogenic carbon and nitrogen in benthic food webs of A Coruña (NW Spain) traced by stable isotopes

    Science.gov (United States)

    Bode, Antonio; Fernández, Consolación; Mompeán, Carmen; Parra, Santiago; Rozada, Fernando; Valencia-Vila, Joaquín; Viana, Inés G.

    2014-08-01

    In this study the effect of inputs of organic matter and anthropogenic nitrogen at small spatial scales were investigated in the benthos of the Ria of A Coruña (NW Spain) using stable carbon and nitrogen isotopes. This ria is characteristically enriched in nutrients provided either by marine processes (as coastal upwelling) or by urban and agricultural waste. Stable isotope composition in trophic guilds of infaunal benthos revealed spatial differences related to their nutrient inputs. The main difference was the presence of an additional chemoautotrophic food web at the site with a large accumulation of organic matter. The enrichment in heavy nitrogen isotopes observed in most compartments suggests the influence of sewage-derived nitrogen, despite large inputs of marine nitrogen. Macroalgae (Fucus vesiculosus) resulted significantly enriched at the site influenced by estuarine waters. In contrast, no differences were found in mussels (Mytilus galloprovincialis), thus suggesting a major dependence on marine nutrient sources for this species. However, the estimations of anthropogenic influence were largely dependent on assumptions required to model the different contributions of sources. The measurement of stable isotope signatures in various compartments revealed that, despite anthropogenic nutrients are readily incorporated into local food webs, a major influence of natural marine nutrient sources cannot be discarded.

  11. FY 1996 Congressional budget request: Budget highlights

    Energy Technology Data Exchange (ETDEWEB)

    1995-02-01

    The FY 1996 budget presentation is organized by the Department`s major business lines. An accompanying chart displays the request for new budget authority. The report compares the budget request for FY 1996 with the appropriated FY 1995 funding levels displayed on a comparable basis. The FY 1996 budget represents the first year of a five year plan in which the Department will reduce its spending by $15.8 billion in budget authority and by $14.1 billion in outlays. FY 1996 is a transition year as the Department embarks on its multiyear effort to do more with less. The Budget Highlights are presented by business line; however, the fifth business line, Economic Productivity, which is described in the Policy Overview section, cuts across multiple organizational missions, funding levels and activities and is therefore included in the discussion of the other four business lines.

  12. 东沙西南海域表层底栖有孔虫碳同位素对冷泉活动的指示%CARBON ISOTOPE OF BENTHIC FORAMINIFERA AND ITS IMPLICATIONS FOR COLD SEEPAGE IN THE SOUTHWESTERN AREA OFF DONGSHA ISLANDS,SOUTH CHINA SEA

    Institute of Scientific and Technical Information of China (English)

    向荣; 方力; 陈忠; 张兰兰; 杜恕环; 颜文; 陈木宏

    2012-01-01

    The depleted carbon isotope (δ13C) of benthic foraminifera was regarded as an important indicator of ancient cold methane seepage. In this study carbon isotope analyses were carried out for 6 benthic fo-raminiferal species from 4 surface sediments with carbonate nodules in the southwestern area off. Dongsha Islands, South China Sea. The carbon isotope of epibenthic species of Discanomalina semiungulata , Cibi-cides wullerstorfi, Cibicides pseudoungerianus and Cibicides lobatulus all show apparent negative excursions compared to the δ13C values at the control sites in the SCS and, in particular, all values of D. semiungulata are depleted. The endobenthic Lenticulina orbicularis also has some negative carbon isotope excursions , while endobenthic Uvigerina auberiana reveals abnormal positive values compared with the controlling sites. The amplitude of δ13 C variability of D. semiungulata (2. ll%o), L. orbicularis (1. 49%o), C. pseudoungerianus (2. 08%o) and U. auberiana (1. 98%o) are apparent larger than that at the controlling sites ((0. 4%o) , and also larger than the δ13C variability (1. l%o) of benthic foraminifera during the last two glacial-interglacial cycles of the SCS. Living benthic foraminifera D. semiungulata and C. lobatulus, which attached on a tube worm, both show obvious depletion of δ13C. We consider that the depleted δ13C values with significantly larger variability observed in benthic foraminiferal species in the southwestern are-a off Dongsha Islands, SCS are possibly caused by cold seeping activity. And the negative excursion of carbon isotope in the living attached benthic foraminifera may indicate an active cold seepage existed in the studied area. We suggest that the epibenthic D. semiungulata be used as a potential indicator of cold seepage in the SCS.%底栖有孔虫碳同位素负偏记录是冷泉活动的重要指标之一.对南海北部东沙西南海域4个含碳酸盐结核的表层沉积物样品中的6种底栖有孔虫进

  13. From Greenland to green lakes: Cultural eutrophication and the loss of benthic pathways in lakes

    DEFF Research Database (Denmark)

    Vadeboncoeur, Y.; Jeppesen, E.; Zanden, M. J. V.

    2003-01-01

    with TP . 100 mg m23, phytoplankton were responsible for nearly 100% of primary production. Benthic contributions ranged from 5 to 80% depending on morphometry and littoral habitat composition in lakes with intermediate phosphorus concentrations. Thus, eutrophication was characterized by a switch from...... benthic to pelagic dominance of primary productivity. Carbon stable isotope analysis showed that the redistribution of primary production entailed a similar shift from periphyton to phytoplankton in the diets of zoobenthos. Benthic and pelagic habitats were energetically linked through food web...

  14. Food web flows through a sub-arctic deep-sea benthic community

    Science.gov (United States)

    Gontikaki, E.; van Oevelen, D.; Soetaert, K.; Witte, U.

    2011-11-01

    The benthic food web of the deep Faroe-Shetland Channel (FSC) was modelled by using the linear inverse modelling methodology. The reconstruction of carbon pathways by inverse analysis was based on benthic oxygen uptake rates, biomass data and transfer of labile carbon through the food web as revealed by a pulse-chase experiment. Carbon deposition was estimated at 2.2 mmol C m -2 d -1. Approximately 69% of the deposited carbon was respired by the benthic community with bacteria being responsible for 70% of the total respiration. The major fraction of the labile detritus flux was recycled within the microbial loop leaving merely 2% of the deposited labile phytodetritus available for metazoan consumption. Bacteria assimilated carbon at high efficiency (0.55) but only 24% of bacterial production was grazed by metazoans; the remaining returned to the dissolved organic matter pool due to viral lysis. Refractory detritus was the basal food resource for nematodes covering ∼99% of their carbon requirements. On the contrary, macrofauna seemed to obtain the major part of their metabolic needs from bacteria (49% of macrofaunal consumption). Labile detritus transfer was well-constrained, based on the data from the pulse-chase experiment, but appeared to be of limited importance to the diet of the examined benthic organisms (food web. Overall, this study provided a unique insight into the functioning of a deep-sea benthic community and demonstrated how conventional data can be exploited further when combined with state-of-the-art modelling approaches.

  15. Verification of uncertainty budgets

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Madsen, B.S.

    2005-01-01

    The quality of analytical results is expressed by their uncertainty, as it is estimated on the basis of an uncertainty budget; little effort is, however, often spent on ascertaining the quality of the uncertainty budget. The uncertainty budget is based on circumstantial or historical data, and th...

  16. Federal budget timetable

    Science.gov (United States)

    This is the federal budget timetable under the Balanced Budget and Emergency Deficit Control Act of 1985 (Gramm-Rudman-Hollings). These deadlines apply to fiscal years (FY) 1987-1991. The deficit reduction measures in Gramm-Rudman-Hollings would lead to a balanced budget in 1991.

  17. Carbon-13 in the world ocean during the last interglaciation and the penultimate glacial maximum: reevaluation of the possible biosphere response to the earth's climatic changes

    Energy Technology Data Exchange (ETDEWEB)

    Duplessy, J.C.; Shackleton, N.J.

    1984-01-01

    A reconstruction of the geographic distribution of carbon-13 in benthic foraminifera that lived during the Last Interglacial period and the Penultimate glaciation provides a global budget of the oceanic delta/sup 13/C during these climatic extremes. During the penultimate glacial to interglacial transition, the mean delta/sup 13/C change of the total CO/sub 2/ dissolved in the ocean was 0.3 per thousand, about half the estimate of Shackleton (1977). This change is equivalent to a transfer of about 4 x 10/sup 17/g of carbon from the biosphere to the ocean.

  18. Proceedings of the Coastal Benthic Boundary Layer Key West Workshop

    Science.gov (United States)

    1997-06-24

    plates of aragonitic green algae (Halimeda, Penicillus, and Udeota), molluscan shells, benthic and planktonic foraminifera , echinoid spines, sponge...Florida Shelf ( Gulf of Mexico waters) to the north, and the Florida Straits to the south. Seismic data from the shelf surrounding the Dry Tortugas...the west Florida carbonate platform. It is bordered to the north by the Gulf of Mexico and to the south by the Straits of Florida. The site is well

  19. E-Science System for Carbon Budget Integration Research of Chinese Terrestrial Ecosystem%中国陆地生态系统碳收支集成研究的e-Science系统构建

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    全球/区域生态系统碳循环研究具有多台站联网观测、多源异构数据、多模型综合分析、跨领域科学家协同工作等特点。以中国陆地生态系统通量观测研究网络(ChinaFLUX)为基础平台,论述建立碳循环科研信息化环境(e-Carbon Science)的迫切性,系统阐述e-Carbon Science的目标、组成、关键技术及研究进展,构建了由"四环境(碳循环数据集成与服务环境、模型模拟环境、可视化分析环境、科研协同工作环境)、三系统(站点、区域、全国尺度陆地生态系统碳收支评估应用系统)"组成的ChinaFLUX e-Carbon Science,形成ChinaFLUX通量数据采集—传输—存储—管理—处理—可视化—共享服务的一体化系统,实现不同尺度的碳收支快速评估与模拟,支撑并促进我国陆地生态系统碳循环研究和生态信息学发展,对我国野外台站网络信息化起到引领和示范作用。%Global and regional ecosystem carbon cycle research is characterized by multi-stations observation networks,multi-sources data with heterogeneous structure,multi-models meta-analysis,and collaboration of scientists across different disciplines.Based on the Chinese Terrestrial Ecosystem Flux Research Network(ChinaFLUX),we proposed an e-Carbon Science with its goals,components,and key techniques and reported current progress.ChinaFLUX e-carbon science consists of four environments(the carbon cycle data integration and service environment,the model simulating environment,the visual analysis environment,and the collaborative scientific research environment) and three application systems(terrestrial carbon budget assessment system at local,regional,and national scales).We developed an integration system of flux data acquisition-transportation-storage-management-processing-visualization-service sharing.ChinaFLUX e-carbon science made rapid carbon budget assessment and simulation possible,promoted the

  20. The offshore benthic fish community

    Science.gov (United States)

    Lantry, Brian F.; Lantry, Jana R.; Weidel, Brian C.; Walsh, Maureen; Hoyle, James A.; Schaner, Teodore; Neave, Fraser B.; Keir, Michael

    2014-01-01

    Lake Ontario’s offshore benthic fish community includes primarily slimy sculpin, lake whitefish, rainbow smelt, lake trout, burbot, and sea lamprey. Of these, lake trout have been the focus of an international restoration effort for more than three decades (Elrod et al. 1995; Lantry and Lantry 2008). The deepwater sculpin and three species of deepwater ciscoes (Coregonus spp.) that were historically important in the offshore benthic zone became rare or were extirpated by the 1960s (Christie 1973; Owens et al. 2003; Lantry et al. 2007b; Roth et al. 2013). Ecosystem changes continue to influence the offshore benthic fish community, including the effects of dreissenid mussels, the near disappearance of burrowing amphipods (Diporeia spp.) (Dermott et al. 2005; Watkins et al. 2007), and the increased abundance and expanded geographic distribution of round goby (see Nearshore Fish Community chapter) (Lantry et al. 2007b). The fish-community objectives for the offshore benthic fish community, as described by Stewart et al. (1999), are:

  1. Application of reservoir characterization and advanced technology to improve recovery and economics in a lower quality shallow shelf carbonate reservoir. End of budget period report, August 3, 1994--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, A.R.; Hinterlong, G.; Watts, G.; Justice, J.; Brown, K.; Hickman, T.S.

    1997-12-01

    The Oxy West Welch project is designed to demonstrate how the use of advanced technology can improve the economics of miscible CO{sub 2} injection projects in a lower quality shallow shelf carbonate reservoir. The research and design phase primarily involves advanced reservoir characterization and accelerating the production response. The demonstration phase will implement the reservoir management plan based on an optimum miscible CO{sub 2} flood as designed in the initial phase. During Budget Period 1, work was completed on the CO{sub 2} stimulation treatments and the hydraulic fracture design. Analysis of the CO{sub 2} stimulation treatment provided a methodology for predicting results. The hydraulic fracture treatment proved up both the fracture design approach a and the use of passive seismic for mapping the fracture wing orientation. Although the 3-D seismic interpretation is still being integrated into the geologic model and interpretation of borehole seismic is still underway, the simulator has been enhanced to the point of giving good waterflood history matches. The simulator-forecasted results for an optimal designed miscible CO{sub 2} flood in the demonstration area gave sufficient economics to justify continuation of the project into Budget Period 2.

  2. Water-budget methods

    Science.gov (United States)

    Healy, Richard W.; Scanlon, Bridget R.

    2010-01-01

    A water budget is an accounting of water movement into and out of, and storage change within, some control volume. Universal and adaptable are adjectives that reflect key features of water-budget methods for estimating recharge. The universal concept of mass conservation of water implies that water-budget methods are applicable over any space and time scales (Healy et al., 2007). The water budget of a soil column in a laboratory can be studied at scales of millimeters and seconds. A water-budget equation is also an integral component of atmospheric general circulation models used to predict global climates over periods of decades or more. Water-budget equations can be easily customized by adding or removing terms to accurately portray the peculiarities of any hydrologic system. The equations are generally not bound by assumptions on mechanisms by which water moves into, through, and out of the control volume of interest. So water-budget methods can be used to estimate both diffuse and focused recharge, and recharge estimates are unaffected by phenomena such as preferential flow paths within the unsaturated zone. Water-budget methods represent the largest class of techniques for estimating recharge. Most hydrologic models are derived from a water-budget equation and can therefore be classified as water-budget models. It is not feasible to address all water-budget methods in a single chapter. This chapter is limited to discussion of the “residual” water-budget approach, whereby all variables in a water-budget equation, except for recharge, are independently measured or estimated and recharge is set equal to the residual. This chapter is closely linked with Chapter 3, on modeling methods, because the equations presented here form the basis of many models and because models are often used to estimate individual components in water-budget studies. Water budgets for streams and other surface-water bodies are addressed in Chapter 4. The use of soil-water budgets and

  3. Sediment Diagenesis and Benthic Flux

    Science.gov (United States)

    Emerson, S.; Hedges, J.

    2003-12-01

    Chemical reactions in marine sediments and the resulting fluxes across the sediment-water interface influence the global carbon cycle and the pH of the sea and affect the abundance of CaCO3 and opal-forming plankton in the ocean. On very long timescales these diagenetic reactions control carbon burial in sedimentary rocks and the oxygen content of the atmosphere. Sedimentary deposits that remain after diagenesis are the geochemical artifacts used for interpreting past changes in ocean circulation, biogeochemical cycles, and climate. This chapter is about the processes of diagenesis and burial of the chemical elements that make up the bulk of the particulate matter that reaches the seafloor (organic matter, CaCO3, SiO2, Fe, Mn, and aluminosilicates).Understanding of sediment diagenesis and benthic fluxes has evolved with advances in both experimental methods and modeling. Measurements of chemical concentrations in sediments, their associated pore waters and fluxes at the sediment-water interface have been used to identify the most important reactions. Because transport in pore waters is usually by molecular diffusion, this medium is conducive to interpretation by models of heterogeneous chemical equilibrium and kinetics. Large chemical changes and manageable transport mechanisms have led to elegant models of sediment diagenesis and great advances in understanding of diagenetic processes.We shall see, though, that the environment does not yield totally to simple models of chemical equilibrium and chemical kinetics, and laboratory determined constants often cannot explain the field observations. For example, organic matter degradation rate constants determined from modeling are so variable that there are essentially no constraints on these values from laboratory experiments. In addition, reaction rates of CaCO3 and opal dissolution determined from modeling pore waters usually cannot be reproduced in laboratory experiments of these reactions. The inability to

  4. Assessing benthic oxygen fluxes in oligotrophic deep sea sediments (HAUSGARTEN observatory)

    Science.gov (United States)

    Donis, Daphne; McGinnis, Daniel F.; Holtappels, Moritz; Felden, Janine; Wenzhoefer, Frank

    2016-05-01

    Benthic oxygen fluxes, an established proxy for total organic carbon mineralization, were investigated in oligotrophic deep sea sediments. We used three different in situ technologies to estimate the benthic oxygen fluxes at an Arctic deep sea site (2500 m depth, HAUSGARTEN observatory) with limiting conditions of low oxygen gradients and fluxes, low turbulence and low particle content in the benthic boundary layer. The resolved eddy covariance turbulent oxygen flux (-0.9±0.2 (SD) mmol O2 m-2 d-1) compared well with simultaneous dissolved oxygen flux measurements carried out with a microprofiler (-1.02±0.3 (SD) mmol O2 m-2 d-1) and total oxygen uptake obtained by benthic chamber incubations (-1.1±0.1 (SD) mmol O2 m-2 d-1). The agreement between these different techniques revealed that microbial-mediated oxygen consumption was dominant at this site. The average benthic flux equals a carbon mineralization rate of 4.3 g C m-2 yr-1, which exceeds the annual sedimentation of particulate organic matter measured by sediment traps. The present study represents a detailed comparison of different in situ technologies for benthic flux measurements at different spatial scales in oligotrophic deep sea sediments. The use of eddy covariance, so far rarely used for deep sea investigations, is presented in detail.

  5. Climate-related uncertainties in projections of the twenty-first century terrestrial carbon budget: off-line model experiments using IPCC greenhouse-gas scenarios and AOGCM climate projections

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Akihiko [Japan Agency for Marine-Earth Science and Technology, Frontier Research Center for Global Change, Yokohama (Japan)

    2005-04-01

    A terrestrial ecosystem model (Sim-CYCLE) was driven by multiple climate projections to investigate uncertainties in predicting the interactions between global environmental change and the terrestrial carbon cycle. Sim-CYCLE has a spatial resolution of 0.5 , and mechanistically evaluates photosynthetic and respiratory CO{sub 2} exchange. Six scenarios for atmospheric-CO{sub 2} concentrations in the twenty-first century, proposed by the Intergovernmental Panel on Climate Change, were considered. For each scenario, climate projections by a coupled atmosphere-ocean general circulation model (AOGCM) were used to assess the uncertainty due to socio-economic predictions. Under a single CO{sub 2} scenario, climate projections with seven AOGCMs were used to investigate the uncertainty stemming from uncertainty in the climate simulations. Increases in global photosynthesis and carbon storage differed considerably among scenarios, ranging from 23 to 37% and from 24 to 81 Pg C, respectively. Among the AOGCM projections, increases ranged from 26 to 33% and from 48 to 289 Pg C, respectively. There were regional heterogeneities in both climatic change and carbon budget response, and different carbon-cycle components often responded differently to a given environmental change. Photosynthetic CO{sub 2} fixation was more sensitive to atmospheric CO{sub 2}, whereas soil carbon storage was more sensitive to temperature. Consequently, uncertainties in the CO{sub 2} scenarios and climatic projections may create additional uncertainties in projecting atmospheric-CO{sub 2} concentrations and climates through the interactive feedbacks between the atmosphere and the terrestrial ecosystem. (orig.)

  6. Budget Summary of Changes

    Data.gov (United States)

    Pension Benefit Guaranty Corporation — The Summary of Changes dataset extracted from PBGC's congressional budget justification. It contains all administrative and program increases and decreases including...

  7. 7 CFR 3402.14 - Budget and budget narrative.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Budget and budget narrative. 3402.14 Section 3402.14 Agriculture Regulations of the Department of Agriculture (Continued) COOPERATIVE STATE RESEARCH, EDUCATION... budget narrative. Applicants must prepare the Budget, Form CSREES-2004, and a budget...

  8. Orbital forcing of deep-sea benthic species diversity

    Science.gov (United States)

    Cronin, T. M.; Raymo, M.E.

    1997-01-01

    Explanations for the temporal and spatial patterns of species biodiversity focus on stability-time, disturbance-mosaic (biogenic microhabitat heterogeneity) and competition-predation (biotic interactions) hypotheses. The stability-time hypothesis holds that high species diversity in the deep sea and in the tropics reflects long-term climatic stability. But the influence of climate change on deep-sea diversity has not been studied and recent evidence suggests that deep-sea environments undergo changes in climatically driven temperature and flux of nutrients and organic-carbon during glacial-interglacial cycles. Here we show that Pliocene (2.85-2.40 Myr) deep-sea North Atlantic benthic ostracod (Crustacea) species diversity is related to solar insolation changes caused by 41,000-yr cycles of Earth's obliquity (tilt). Temporal changes in diversity, as measured by the Shannon- Weiner index, H(S), correlate with independent climate indicators of benthic foraminiferal oxygen-isotope ratios (mainly ice volume) and ostracod Mg:Ca ratios (bottomwater temperature). During glacial periods, H(S) = 0.2-0.6, whereas during interglacials, H(S) = 1.2-1.6, which is three to four times as high. The control of deep-sea benthic diversity by cyclic climate change at timescales of 103-104 yr does not support the stability-time hypothesis because it shows that the deep sea is a temporally dynamic environment. Diversity oscillations reflect large-scale response of the benthic community to climatically driven changes in either thermohaline circulation, bottom temperature (or temperature-related factors) and food, and a coupling of benthic diversity to surface productivity.

  9. Budgeting for PACS.

    Science.gov (United States)

    Sim, Lh

    2008-10-01

    There are a number of models for the acquisition of digital image management systems. The specific details for development of a budget for a PACS/RIS acquisition will depend upon the acquisition model - although there are similarities in the overarching principles and general information, particularly concerning the radiology service requirements that will drive budget considerations.While budgeting for PACS/RIS should follow the same principles as budgeting for any new technology, it is important to understand how far the implementation of digital image management systems can reach in a healthcare setting. Accurate identification of those elements of the healthcare service that will be affected by a PACS/RIS implementation is a critical component of successful budget formation and of the success of any business case and subsequent project that relies on those budget estimates.A budget for a PACS/RIS capital acquisition project should contain capital and recurrent elements. The capital is associated with the acquisition of the system in a purchase model and capital budget may also be required for upgrade - depending upon a facility's financial management processes.The recurrent (or operational) cost component for the PACS/RIS is associated with maintaining the system(s) in a sustainable operational state.It is also important to consider the service efficiencies, cost savings and service quality improvements that PACS/RIS can generate and include these factors into the economic analysis of any proposal for a PACS/RIS project.

  10. Budgeting Based on Results

    Science.gov (United States)

    Cooper, Kelt L.

    2011-01-01

    Every program in a school or school district has, or once had, a purpose. The purpose was most likely promoted, argued and debated among school constituencies--parents, teachers, administrators and school board members--before it was eventually approved. This process occurs year after year, budget after budget. In itself, this is not necessarily a…

  11. Managing the Student Budget.

    Science.gov (United States)

    Faller, Martha Lewkus

    1984-01-01

    Looks at the factors complicating the management of student worker budgets in libraries (e.g., the number of separate but interrelated budgets involved). Proposes a budgetary system incorporating double-entry bookkeeping, continuous proving, and combination receipts and disbursements. Considers the advantages of the system and details procedures.…

  12. Learning From Low Budgets

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Chinese filmmakers turn small-budget productions into box-office successes Organizers of China’s upcoming film festivals are finally giving recognition to the little guys—low budget films—to encourage a generation of young,talented directors.

  13. Novel developments in benthic modelling to address scientific and policy challenges

    Science.gov (United States)

    Lessin, Gennadi; Artioli, Yuri; Bruggeman, Jorn; Aldridge, John; Blackford, Jerry

    2016-04-01

    Understanding the role of benthic systems in supporting, regulating and providing marine ecosystem services requires better understanding of their functioning and their response and resilience to stressors. Novel observational methods for the investigation of dynamics of benthic-pelagic coupling in shelf seas are being developed and new data is being collected. Therefore there is an increasing demand for robust representation of benthic processes in marine biogeochemical and ecosystem models, which would improve our understanding of whole systems and benthic-pelagic coupling, rather than act as mere closure terms for pelagic models. However, for several decades development of benthic models has lagged behind their pelagic counterparts. To address contemporary scientific, policy and societal challenges, the biogeochemical and ecological model ERSEM (European Regional Seas Ecosystem Model), including its benthic sub-model, was recently recoded in a scalable and modular format adopting the approach of FABM (Framework for Aquatic Biogeochemical Models). Within the Shelf Sea Biogeochemistry research programme, a series of additional processes have been included, such as a sedimentary carbonate system, a resuspendable fluff layer, and the simulation of advective sediments. It was shown that the inclusion of these processes changes the dynamics of benthic-pelagic fluxes as well as modifying the benthic food web. Comparison of model results with in-situ data demonstrated a general improvement of model performance and highlighted the importance of the benthic system in overall ecosystem dynamics. As an example, our simulations have shown that inclusion of a resuspendable fluff layer facilitates regeneration of inorganic nutrients in the water column due to degradation of resuspended organic material by pelagic bacteria. Moreover, the composition of fluff was found to be important for trophic interactions, and therefore indirectly affects benthic community composition. Where

  14. A first-order analysis of the potential role of CO2 fertilization to affect the global carbon budget: A comparison of four terrestrial biosphere models

    Science.gov (United States)

    Kicklighter, D.W.; Bruno, M.; Donges, S.; Esser, G.; Heimann, Martin; Helfrich, J.; Ift, F.; Joos, F.; Kaduk, J.; Kohlmaier, G.H.; McGuire, A.D.; Melillo, J.M.; Meyer, R.; Moore, B.; Nadler, A.; Prentice, I.C.; Sauf, W.; Schloss, A.L.; Sitch, S.; Wittenberg, U.; Wurth, G.

    1999-01-01

    We compared the simulated responses of net primary production, heterotrophic respiration, net ecosystem production and carbon storage in natural terrestrial ecosystems to historical (1765 to 1990) and projected (1990 to 2300) changes of atmospheric CO2 concentration of four terrestrial biosphere models: the Bern model, the Frankfurt Biosphere Model (FBM), the High-Resolution Biosphere Model (HRBM) and the Terrestrial Ecosystem Model (TEM). The results of the model intercomparison suggest that CO2 fertilization of natural terrestrial vegetation has the potential to account for a large fraction of the so-called 'missing carbon sink' of 2.0 Pg C in 1990. Estimates of this potential are reduced when the models incorporate the concept that CO2 fertilization can be limited by nutrient availability. Although the model estimates differ on the potential size (126 to 461 Pg C) of the future terrestrial sink caused by CO2 fertilization, the results of the four models suggest that natural terrestrial ecosystems will have a limited capacity to act as a sink of atmospheric CO2 in the future as a result of physiological constraints and nutrient constraints on NPP. All the spatially explicit models estimate a carbon sink in both tropical and northern temperate regions, but the strength of these sinks varies over time. Differences in the simulated response of terrestrial ecosystems to CO2 fertilization among the models in this intercomparison study reflect the fact that the models have highlighted different aspects of the effect of CO2 fertilization on carbon dynamics of natural terrestrial ecosystems including feedback mechanisms. As interactions with nitrogen fertilization, climate change and forest regrowth may play an important role in simulating the response of terrestrial ecosystems to CO2 fertilization, these factors should be included in future analyses. Improvements in spatially explicit data sets, whole-ecosystems experiments and the availability of net carbon exchange

  15. Spatial variation in organic matter utilization by benthic communities from Yura River-Estuary to offshore of Tango Sea, Japan

    Science.gov (United States)

    Antonio, Emily S.; Kasai, Akihide; Ueno, Masahiro; Won, Nam-il; Ishihi, Yuka; Yokoyama, Hisashi; Yamashita, Yoh

    2010-01-01

    We investigated the distribution of δ 13C and δ 15N of organic matter among benthic communities from the upper estuary of Yura River to offshore of Tango Sea, Japan, to determine spatial variation in utilization of organic matter by benthic communities. The δ 13C values of benthic animals ranged from -27 to -15‰ in the upper estuary, -21 to -15‰ in the lower estuary, -20 to -16‰ in the shallow coast (5-10 m depths), -18 to -16‰ in the deep coast (30-60 m depths) and -19 to -15‰ in offshore (100-150 m depths) stations. Adapting the dual isotope values to mixing models, we estimated the relative contributions of potential food sources to the benthos diet. Phytoplankton and macroalgae that intruded the estuary in summer were utilized as alternative food aside from the terrestrial-origin organic matter assimilated by the estuarine benthic consumers. Resuspended benthic microalgae were important source of energy in the shallow coastal stations, while abundant supply of phytodetritus fueled the deep coastal and offshore benthic food webs. Spatial difference in the diet of benthic communities depends largely on the shifts in the primary carbon source. Thus, benthic communities are important link of autochthonous/allochthonous production and secondary production in the continuous river-estuary-marine system.

  16. Environmental impacts of coastal farming: carbon and nitrogen budgets for trout farming activity in Kaldbaksfjørđur (Faroe Islands)

    DEFF Research Database (Denmark)

    Nordi, Gunnvør a; Glud, Ronnie N.; Gaard, Eilif

    2011-01-01

    Flow of organic carbon (OC) and nitrogen through a sea cage trout farm was calculated on the basis of detailed studies of the farming operation, water circulation, OC and nutrient transport and recycling processes in sediment. A third of the OC and nitrogen provided by fish food was incorporated...

  17. Who needs budgets?

    Science.gov (United States)

    Hope, Jeremy; Fraser, Robin

    2003-02-01

    Budgeting, as most corporations practice it, should be abolished. That may sound radical, but doing so would further companies' long-running efforts to transform themselves into developed networks that can nimbly adjust to market conditions. Most other building blocks are in place, but companies continue to restrict themselves by relying on inflexible budget processes and the command-and-control culture that budgeting entails. A number of companies have rejected the foregone conclusions embedded in budgets, and they've given up the self-interested wrangling over what the data indicate. In the absence of budgets, alternative goals and measures--some financial, such as cost-to-income ratios, and some nonfinancial, such as time to market-move to the foreground. Companies that have rejected budgets require employees to measure themselves against the performance of competitors and against internal peer groups. Because employees don't know whether they've succeeded until they can look back on the results of a given period, they must use every ounce of energy to ensure that they beat the competition. A key feature of many companies that have rejected budgets is the use of rolling forecasts, which are created every few months and typically cover five to eight quarters. Because the forecasts are regularly revised, they allow companies to continuously adapt to market conditions. The forecasting practices of two such companies, both based in Sweden, are examined in detail: the bank Svenska Handelsbanken and the wholesaler Ahlsell. Though the first companies to reject budgets were located in Northern Europe, organizations that have gone beyond budgeting can be found in a range of countries and industries. Their practices allow them to unleash the power of today's management tools and realize the potential of a fully decentralized organization.

  18. Assessing the suitability of benthic foraminiferal morpho-groups to reconstruct paleomonsoon from Bay of Bengal

    Indian Academy of Sciences (India)

    M Manasa; Rajeev Saraswat; Rajiv Nigam

    2016-04-01

    Temporal changes in benthic foraminiferal morpho-groups were suggested as an effective proxy to reconstructpast monsoon intensity from the Arabian Sea. Here, in order to test the applicability of temporalvariation in morpho-groups to reconstruct past monsoon intensity from the Bay of Bengal, we havedocumented recent benthic foraminiferal distribution from the continental shelf region of the northwesternBay of Bengal. Based on the external morphology, benthic foraminifera were categorized intorounded symmetrical (RSBF) and angular asymmetrical benthic foraminifera (AABF). Additionally, afew other dominant groups were also identified based on test composition (agglutinated, calcareous) andabundance (Asterorotalids and Nonions). The relative abundance of each group was compared with theambient physico-chemical conditions, including dissolved oxygen, organic matter, salinity and temperature.We report that the RSBF are abundant in comparatively warm and well oxygenated waters of lowsalinity, suggesting a preference for high energy environment, whereas AABF dominate relatively cold,hypersaline deeper waters with low dissolved oxygen, indicating a low energy environment. The agglutinatedforaminifera, Asterorotalids and Nonions dominate shallow water, low salinity regions, whereasthe calcareous benthic foraminiferal abundance increases away from the riverine influx regions. Foodavailability, as estimated from organic carbon abundance in sediments, has comparatively less influenceon faunal distribution in the northwestern Bay of Bengal, as compared to dissolved oxygen, temperatureand salinity. We conclude that the factors associated with freshwater influx affect the distributionof benthic foraminiferal morpho-groups in the northwestern Bay of Bengal and thus it can be used toreconstruct past monsoon intensity from the Bay of Bengal.

  19. Flow of light energy in benthic photosynthetic microbial mats

    Energy Technology Data Exchange (ETDEWEB)

    Al-Najjar, Mohammad Ahmad A.

    2010-12-15

    The work in this thesis demonstrates the assessment of the energy budget inside microbial mat ecosystems, and the factors affecting light utilization efficiency. It presents the first balanced light energy budget for benthic microbial mat ecosystems, and shows how the budget and the spatial distribution of the local photosynthetic efficiencies within the euphotic zone depend on the absorbed irradiance (Jabs). The energy budget was dominated by heat dissipation on the expense of photosynthesis. The maximum efficiency of photosynthesis was at light limiting conditions When comparing three different marine benthic photosynthetic ecosystems (originated from Abu-Dhabi, Arctic, and Exmouth Gulf in Western Australia), differences in the efficiencies were calculated. The results demonstrated that the maximum efficiency depended on mat characteristics affecting light absorption and scattering; such as, photopigments ratio and distribution, and the structural organization of the photosynthetic organisms relative to other absorbing components of the ecosystem (i.e., EPS, mineral particles, detritus, etc.). The maximum efficiency decreased with increasing light penetration depth, and increased with increasing the accessory pigments (phycocyanin and fucoxanthin)/chlorophyll ratio. Spatial heterogeneity in photosynthetic efficiency, pigment distribution, as well as light acclimation in microbial mats originating from different geographical locations was investigated. We used a combined pigment imaging approach (variable chlorophyll fluorescence and hyperspectral imaging), and fingerprinting approach. For each mat, the photosynthetic activity was proportional to the local pigment concentration in the photic zone, but not for the deeper layers and between different mats. In each mat, yield of PSII and E1/2 (light acclimation) generally decreased in parallel with depth, but the gradients in both parameters varied greatly between samples. This mismatch between pigments concentration

  20. FY 1997 congressional budget request: Budget highlights

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    This is an overview of the 1997 budget request for the US DOE. The topics of the overview include a policy overview, the budget by business line, business lines by organization, crosswalk from business line to appropriation, summary by appropriation, energy supply research and development, uranium supply and enrichment activities, uranium enrichment decontamination and decommissioning fund, general science and research, weapons activities, defense environmental restoration and waste management, defense nuclear waste disposal, departmental administration, Office of the Inspector General, power marketing administrations, Federal Energy Regulatory commission, nuclear waste disposal fund, fossil energy research and development, naval petroleum and oil shale reserves, energy conservation, economic regulation, strategic petroleum reserve, energy information administration, clean coal technology and a Department of Energy Field Facilities map.

  1. Budget Automation System

    Data.gov (United States)

    U.S. Environmental Protection Agency — BAS is the central Agency system used to integrate strategic planning, annual planning, budgeting and financial management. BAS contains resource (dollars and FTE),...

  2. Marine benthic algae of Namibia

    Directory of Open Access Journals (Sweden)

    Jordi Rull Lluch

    2002-12-01

    Full Text Available The first comprehensive study of the marine algal flora of Namibia including descriptions and illustrations of most species is presented. The main objective of this work is to report a flora that, until now, has scarcely been studied. The work compiles all the available information on the marine benthic flora of Namibia and provides new data about it composition and biogeography, as well as detailed descriptions and remarks of most of its species. The samples on which this study is based were collected between 1986 and 1989 in the eulittoral and the upper sublittoral zones of the north half of the Namibian coast. According to the present data, the marine benthic flora of Namibia comprises 196 taxa (147 Rhodophyceae, 20 Phaeophyceae, 15 Ulvophyceae, 6 Cladophorophyceae and 8 Bryopsidophyceae, 21 of which has not been recorded from this coasts. This temperate flora is mainly characterized by a low number of species, a low proportion of Phaeophyceae and a high degree of endemism. Concerning the species number, the flora is quite poor due to both the scarce availability of colonizable substratum and the low diversity of habitats. On the other hand, the low proportion of Phaeophyceae is the reason for which the R/P and (R+C/P ratios take disproportionately high values and so they are not useful in this geographical area. As regards the degree of endemism, the marine benthic flora of Namibia includes quite a high number of taxa endemic to southern Africa (55 taxa; 28.1% of the flora; 25 of these 55 taxa (12.8% of the flora are endemic to the biogeographic Benguela Marine Province and only Acrosorium cincinnatum is endemic to the Namibian coasts.

  3. Mechanisms of temporary adhesion in benthic animals

    NARCIS (Netherlands)

    Dodou, D.; Breedveld, P.; Winter, J.C.F.; Dankelman, J.; Leeuwen, van J.L.

    2011-01-01

    Adhesive systems are ubiquitous in benthic animals and play a key role in diverse functions such as locomotion, food capture, mating, burrow building, and defence. For benthic animals that release adhesives, surface and material properties and external morphology have received little attention compa

  4. Mechanisms of temporary adhesion in benthic animals

    NARCIS (Netherlands)

    Dodou, D.; Breedveld, P.; Winter, J.C.F.; Dankelman, J.; Leeuwen, van J.L.

    2011-01-01

    Adhesive systems are ubiquitous in benthic animals and play a key role in diverse functions such as locomotion, food capture, mating, burrow building, and defence. For benthic animals that release adhesives, surface and material properties and external morphology have received little attention

  5. Morphotype patterns of Norwegian Sea deep-sea benthic foraminifera and ecological implications

    Science.gov (United States)

    Corliss, Bruce H.; Chen, Christina

    1988-08-01

    Deep-sea benthic foraminifera from Norwegian Sea surface sediments are classified into morphotypes on the basis of test shape and nature of test coiling and show distinct patterns with water depth. The morphotype data are used to determine microhabitat patterns of the foraminifera, which are suggested to be related to the organic-carbon content of the surficial deep-sea sediments.

  6. Impact of topographic aspect and vegetation (native and reforested areas) on soil organic carbon and nitrogen budgets in Mediterranean natural areas.

    Science.gov (United States)

    Lozano-García, Beatriz; Parras-Alcántara, Luis; Brevik, Eric C

    2016-02-15

    Soil organic carbon (SOC) plays a critical role in the global carbon (C) cycle, and C sequestration in forest soils can represent a C sink. A relevant question is how does SOC changes in space and time; consequently, the study of the influence of topographic aspect on SOC stocks (SOCS) is very important to build a complete understanding of the soil system. In this line, four topographic aspects, north (N), south (S), east (E) and west (W) were studied under two different plant communities; native forests (NF) and reforested areas (RF) in the Despeñaperros Natural Park (S Spain). Five soil profiles were sampled at each of six different sites, 2 sites for NF (N and E) and 4 sites for RF (N, S, E and W). Soil properties were studied at different depths using soil control sections (S1: 0-25 cm; S2: 25-50 cm; S3: 50-75 cm). The results indicate that RF (N: 147.1 Mg ha(-1); E: 137.3 Mg ha(-1); W: 124.9 Mg ha(-1) and S: 87.0 Mg ha(-1)) had increased total SOCS compared to NF (N: 110.4 Mg ha(-1) and E: 80.9 Mg ha(-1)), and that SOCS in the N position were higher than in the other topographic aspects. Therefore, the results suggest that topographic aspect should be included in SOCS models and estimations at local and regional scales.

  7. BUDGET AND PUBLIC DEBT

    Directory of Open Access Journals (Sweden)

    Morar Ioan Dan

    2014-12-01

    Full Text Available The issue of public budgeting is an important issue for public policy of the state, for the simple reason that no money from the state budget can not promote public policy. Budgetary policy is official government Doctrine vision mirror and also represents a starting point for other public policies, which in turn are financed by the public budget. Fiscal policy instruments at its disposal handles the public sector in its structure, and the private sector. Tools such as grant, budgetary allocation, tax, welfare under various forms, direct investments and not least the state aid is used by the state through their budgetary policies to directly and indirectly infuence sector, and the private. Fiscal policies can be grouped according to the structure of the public sector in these components, namely fiscal policy, budgeting and resource allocation policies for financing the budget deficit. An important issue is the financing of the budget deficit budgetary policies. There are two funding possibilities, namely, the higher taxes or more axles site and enter the second call to public loans. Both options involve extra effort from taxpayers in the current fiscal year when they pay higher taxes or a future period when public loans will be repaid. We know that by virtue of "fiscal pact" structural deficits of the member countries of the EU are limited by the European Commission, according to the macro structural stability and budget of each Member State. This problem tempers to some extent the governments of the Member States budgetary appetite, but does not solve the problem of chronic budget deficits. Another issue addressed in this paper is related to the public debt, the absolute amount of its relative level of public datoriri, about the size of GDP, public debt financing and its repayment sources. Sources of public debt issuance and monetary impact on the budget and monetary stability are variables that must underpin the justification of budgetary

  8. Stylized facts in microalgal growth: interpretation in a dynamic energy budget context.

    Science.gov (United States)

    Lorena, António; Marques, Gonçalo M; Kooijman, S A L M; Sousa, Tânia

    2010-11-12

    A dynamic energy budget (DEB) model for microalgae is proposed. This model deviates from the standard DEB model as it needs more reserves to cope with the variation of assimilation pathways, requiring a different approach to growth based on the synthesizing unit (SU) theory for multiple substrates. It is shown that the model is able to accurately predict experimental data in constant and light-varying conditions with most of the parameter values taken directly from the literature. Also, model simulations are shown to be consistent with stylized facts (SFs) concerning NC ratio. These SFs are reinterpreted and the general conclusion is that all forcing variables (dilution rate, temperature and irradiance) impose changes in the nitrogen or carbon limitation status of the population, and consequently on reserve densities. Model predictions are also evaluated in comparison with SFs on chlorophyll concentration. It is proposed that an extra structure, more dependent on the nitrogen reserve, is required to accurately model chlorophyll dynamics. Finally, SFs concerning extracellular polymeric substances (EPSs) production by benthic diatoms are collected and interpreted and a formulation based on product synthesis and rejection flux is proposed for the EPSs production rate.

  9. Interactive effects of nocturnal transpiration and climate change on the root hydraulic redistribution and carbon and water budgets of southern United States pine plantations.

    Science.gov (United States)

    Domec, Jean-Christophe; Ogée, Jérôme; Noormets, Asko; Jouangy, Julien; Gavazzi, Michael; Treasure, Emrys; Sun, Ge; McNulty, Steve G; King, John S

    2012-06-01

    Deep root water uptake and hydraulic redistribution (HR) have been shown to play a major role in forest ecosystems during drought, but little is known about the impact of climate change, fertilization and soil characteristics on HR and its consequences on water and carbon fluxes. Using data from three mid-rotation loblolly pine plantations, and simulations with the process-based model MuSICA, this study indicated that HR can mitigate the effects of soil drying and had important implications for carbon uptake potential and net ecosystem exchange (NEE), especially when N fertilization is considered. At the coastal site (C), characterized by deep organic soil, HR increased dry season tree transpiration (T) by up to 40%, and such an increase affected NEE through major changes in gross primary productivity (GPP). Deep-rooted trees did not necessarily translate into a large volume of HR unless soil texture allowed large water potential gradients to occur, as was the case at the sandy site (S). At the Piedmont site (P) characterized by a shallow clay-loam soil, HR was low but not negligible, representing up to 10% of T. In the absence of HR, it was predicted that at the C, S and P sites, annual GPP would have been diminished by 19, 7 and 9%, respectively. Under future climate conditions HR was predicted to be reduced by up to 25% at the C site, reducing the resilience of trees to precipitation deficits. The effect of HR on T and GPP was predicted to diminish under future conditions by 12 and 6% at the C and P sites, respectively. Under future conditions, T was predicted to stay the same at the P site, but to be marginally reduced at the C site and slightly increased at the S site. Future conditions and N fertilization would decrease T by 25% at the C site, by 15% at the P site and by 8% at the S site. At the C and S sites, GPP was estimated to increase by 18% and by >70% under future conditions, respectively, with little effect of N fertilization. At the P site, future

  10. Greenhouse gas budget of agricultural systems: real possibility or dream?

    Science.gov (United States)

    Neftel, A.; Ammann, C.; Calanca, P.; Fuhrer, J.; Leifeld, J.; Jocher, M.; Volk, M.

    2003-04-01

    It is now widely accepted that emission of greenhouse gases (GHG) by human activities are causing an increase of global mean temperature. Model calculations have shown that the rate of increase might have a decisive influence on the stability of the climate. It is therefore crucial to slow down the increase of GHG concentrations in the atmosphere. Storage of carbon in the terrestrial biosphere is mentioned as one possibility in the Kyoto protocol. Mitigation options to decrease GHG emissions in agricultural systems as well as to increase carbon stock in agricultural soils are in discussion. The quantification and verification of the GHG budget is a prerequisite to establish a trade within the Kyoto protocol. On the scientific level this comes down to a greenhouse gas budget for agricultural systems. Comparability and interpretation of GHG budgets depends on an appropriate and consistent choice of the considered system, especially the system boundaries. In this presentation we discuss the feasibility of such a budget for a the smallest unit: the yearly budget of grassland system. Differences between GHG budget and carbon budget will be assessed.

  11. Decomposing uncertainties in the future terrestrial carbon budget associated with emission scenario, climate projection, and ecosystem simulation using the ISI-MIP result

    Directory of Open Access Journals (Sweden)

    K. Nishina

    2014-10-01

    Full Text Available Changes to global net primary production (NPP, vegetation biomass carbon (VegC, and soil organic carbon (SOC estimated by six global vegetation models (GVM obtained from an Inter-Sectoral Impact Model Intercomparison Project study were examined. Simulation results were obtained using five global climate models (GCM forced with four representative concentration pathway (RCP scenarios. To clarify which component (emission scenarios, climate projections, or global vegetation models contributes the most to uncertainties in projected global terrestrial C cycling by 2100, analysis of variance (ANOVA and wavelet clustering were applied to 70 projected simulation sets. In the end of simulation period, the changes from the year of 2000 in all three variables considerably varied from net negative to positive values. ANOVA revealed that the main sources of uncertainty are different among variables and depend on the projection period. We determined that in the global VegC, and SOC projections, GVMs dominate uncertainties (60 and 90%, respectively rather than climate driving scenarios, i.e., RCPs and GCMs. These results suggested that we don't have still enough resolution among each RCP scenario to evaluate climate change impacts on ecosystem conditions in global terrestrial C cycling. In addition, we found that the contributions of each uncertainty source were spatio-temporally heterogeneous and differed among the GVM variables. The dominant uncertainty source for changes in NPP and VegC varies along the climatic gradient. The contribution of GVM to the uncertainty decreases as the climate division gets cooler (from ca. 80% in the equatorial division to 40% in the snow climatic division. To evaluate the effects of climate change on ecosystems with practical resolution in RCP scenarios, GVMs require further improvement to reduce the uncertainties in global C cycling as much as, if not more than, GCMs. Our study suggests that the improvement of GVMs is a

  12. Budgeting and Beyond

    DEFF Research Database (Denmark)

    Rohde, Carsten

    Budgets and budget control has been known since the early 19th century1. However the use of budget control was until the beginning of the 1920ies in US primarily related to governmental units and states and to a minor extent to business units in practice. At that time James McKinsey describes...... budgetary control as involving the following: 1. The statement of the plans of all the departments of the business for a certain period of time in the form of estimates 2. The coordination of these estimates into a well-balanced program for the business as a whole. 3. The preparation of reports showing...... a comparison between the actual and the estimated performance, and the revision of the original plans when these reports show that such a revision is necessary. As can be seen from the statement budgetary control includes at the same time a planning and coordination mechanism for actions and performance ex...

  13. Food and disturbance effects on Arctic benthic biomass and production size spectra

    Science.gov (United States)

    Górska, Barbara; Włodarska-Kowalczuk, Maria

    2017-03-01

    Body size is a fundamental biological unit that is closely coupled to key ecological properties and processes. At the community level, changes in size distributions may influence energy transfer pathways in benthic food webs and ecosystem carbon cycling; nevertheless they remain poorly explored in benthic systems, particularly in the polar regions. Here, we present the first assessment of the patterns of benthic biomass size spectra in Arctic coastal sediments and explore the effects of glacial disturbance and food availability on the partitioning of biomass and secondary productivity among size-defined components of benthic communities. The samples were collected in two Arctic fjords off west Spitsbergen (76 and 79°N), at 6 stations that represent three regimes of varying food availability (indicated by chlorophyll a concentration in the sediments) and glacial sedimentation disturbance intensity (indicated by sediment accumulation rates). The organisms were measured using image analysis to assess the biovolume, biomass and the annual production of each individual. The shape of benthic biomass size spectra at most stations was bimodal, with the location of a trough and peaks similar to those previously reported in lower latitudes. In undisturbed sediments macrofauna comprised 89% of the total benthic biomass and 56% of the total production. The lower availability of food resources seemed to suppress the biomass and secondary production across the whole size spectra (a 6-fold decrease in biomass and a 4-fold decrease in production in total) rather than reshape the spectrum. At locations where poor nutritional conditions were coupled with disturbance, the biomass was strongly reduced in selected macrofaunal size classes (class 10 and 11), while meiofaunal biomass and production were much higher, most likely due to a release from macrofaunal predation and competition pressure. As a result, the partitioning of benthic biomass and production shifted towards meiofauna

  14. 基于生物质能的芒属(Miscanthus)植物碳动态和收支研究进展%A review on carbon dynamics and budget of biomass energy species of Miscanthus spp.

    Institute of Scientific and Technical Information of China (English)

    欧阳旭; 张亚茹; 李跃林

    2013-01-01

    Miscanthus in European countries as a strategy to relieve the energy crisis and greenhouse effects, study in our country is still at a primary stage. The traditional agricultural use mode in China decided that researchers tended to pay more attention on grassland in northern China than that in southern China. Previous studies on grassland in south China focused on ecological restoration, seldom works were about the CO2 exchange capacity at the ecosystem level. However, with the continuing increase in carbon dioxide and its effects on global warming, researches on biomass plant and its carbon sink function become more and more important. Nearly 6.7×107 ha of degraded grassland in mountain areas in southern China are urgent to be restored or in the process of restoration. Miscanthus grasslands have a low demand for nutrient inputs, they may also be produced with little or no pesticide use, and make full use of natural resources such as light and water, and they have high water use and nutrient use efficiency, which make it reach the biomass plant criteria. Compared to other biomass sources, C4 plants outyield C3 plant due to their more efficient photosynthetic pathway. It is worthy to notice that C4 Miscanthus grasses have great carbon sequestration capacity and potential energy in the biomass with high light use efficiency. Hence, a full assessment of carbon dynamics and budgets for Miscanthus grasses are needed. This paper reviewed the current situation of researches on Miscanthus biomass at home and abroad, and concentrated on studies of carbon dynamics and budgets of biomass energy in Miscanthus grasses at ecosystem level. More objective assessment methods of Miscanthus carbon sequestration function at the ecosystem were discussed. Meanwhile, based on the studies of biomass process, research history and current situation of grass land in south China, it was illustrated that the rational exploitation and utilization of biomass energy resources in degraded grasslands brings

  15. Spatial-temporal feeding dynamics of benthic communities in an estuary-marine gradient

    Science.gov (United States)

    Antonio, Emily S.; Kasai, Akihide; Ueno, Masahiro; Ishihi, Yuka; Yokoyama, Hisashi; Yamashita, Yoh

    2012-10-01

    We investigated the fluctuations of carbon and nitrogen stable isotope ratios in benthic consumers and their potential food sources to determine the spatial and temporal variations in the utilization of available organic matter, indicating the origin and pathways of energy from Yura Estuary to Tango Sea, Japan. Field samplings were conducted from the upper estuary to offshore with sampling frequency of twice per season from April (spring) 2006 to February (winter) 2007. The δ13C signatures of the upper and lower estuary benthos showed depleted and in wide range (-28.9‰ to -13.5‰) compared to the enriched and within narrow range signatures of marine benthos (-20.6‰ to -14.0‰) in all seasons. On the contrary, the δ15N signatures of benthic communities showed decreasing trend seaward and summer values were different from the other seasons. Using the dual isotope and multisource mixing models, we estimated the relative contributions of potential food sources to the benthos diet. River POM played an important source of energy for the estuarine benthos, especially in winter when river discharge was high. Marine POM served as an important alternative food for the estuarine benthos from spring to autumn when seawater intruded the bottom estuary. Benthic microalgae were the major food source at the shallow coast throughout the year, while marine POM fueled the deep coast and offshore benthic food webs. Spatial and temporal feeding variations in estuarine benthic communities were driven by the hydrology of the estuary, whereas primary production and transport of food source dictated diet variations of marine benthic communities. The elucidation of the dynamic energy subsidy among aquatic systems highlights the importance of the land-sea transition zones that is crucial for benthic secondary productions.

  16. Benthic foraminifera show some resilience to ocean acidification in the northern Gulf of California, Mexico.

    Science.gov (United States)

    Pettit, L R; Hart, M B; Medina-Sánchez, A N; Smart, C W; Rodolfo-Metalpa, R; Hall-Spencer, J M; Prol-Ledesma, R M

    2013-08-30

    Extensive CO2 vents have been discovered in the Wagner Basin, northern Gulf of California, where they create large areas with lowered seawater pH. Such areas are suitable for investigations of long-term biological effects of ocean acidification and effects of CO2 leakage from subsea carbon capture storage. Here, we show responses of benthic foraminifera to seawater pH gradients at 74-207m water depth. Living (rose Bengal stained) benthic foraminifera included Nonionella basispinata, Epistominella bradyana and Bulimina marginata. Studies on foraminifera at CO2 vents in the Mediterranean and off Papua New Guinea have shown dramatic long-term effects of acidified seawater. We found living calcareous benthic foraminifera in low pH conditions in the northern Gulf of California, although there was an impoverished species assemblage and evidence of post-mortem test dissolution.

  17. Empirical approaches to more accurately predict benthic-pelagic coupling in biogeochemical ocean models

    Science.gov (United States)

    Dale, Andy; Stolpovsky, Konstantin; Wallmann, Klaus

    2016-04-01

    The recycling and burial of biogenic material in the sea floor plays a key role in the regulation of ocean chemistry. Proper consideration of these processes in ocean biogeochemical models is becoming increasingly recognized as an important step in model validation and prediction. However, the rate of organic matter remineralization in sediments and the benthic flux of redox-sensitive elements are difficult to predict a priori. In this communication, examples of empirical benthic flux models that can be coupled to earth system models to predict sediment-water exchange in the open ocean are presented. Large uncertainties hindering further progress in this field include knowledge of the reactivity of organic carbon reaching the sediment, the importance of episodic variability in bottom water chemistry and particle rain rates (for both the deep-sea and margins) and the role of benthic fauna. How do we meet the challenge?

  18. Deep-sea benthic foraminiferal record of the paleoceanography in the southern Okinawa Trough over the last 20 000 years

    Institute of Scientific and Technical Information of China (English)

    翦知湣; 陈荣华; 李保华

    1996-01-01

    Quantitative analyses have been carried out on benthic foraminifera from 66 samples of Core 255 in the southern Okinawa Trough, in combination with the stable isotopic analyses of planktonic and benthic foraminifera and AMS 14C dating, in order to reconstruct the history of change under deep water conditions and surface paleoproduclivity over the last 20 000 years. The variations in the ratio of agglutinants in benthic foraminiferal fauna and the ratio of fragments in planktonic foraminifera] fauna indicate higher carbonate dissolution during the postglacial stage than during the glacial stage. The distribution of species and the results of Q-mode factor analysis show that there are three distinctly different benthic foraminiferal assemblages during the glacial, deglacial and postglacial stages in the Okinawa Trough over the last 20000 years: the glacial Bulimina aculeata assemblage (especially the dominant species Uvigerina pereyrina) is associated with high surface primary productivity and organic mat

  19. Public Budget Database - Budget Authority and offsetting receipts 1976-Current

    Data.gov (United States)

    Executive Office of the President — This file contains historical budget authority and offsetting receipts for 1976 through the current budget year, as well as four years of projections. It can be used...

  20. 小麦-玉米-大豆轮作下黑土农田土壤呼吸与碳平衡%Soil respiration and carbon budget in black soils of wheatmaize-soybean rotation system

    Institute of Scientific and Technical Information of China (English)

    梁尧; 韩晓增; 乔云发; 李禄军; 尤孟阳

    2012-01-01

    农田生态系统是陆地生态系统的重要组成部分,探讨农田生态系统的土壤呼吸与碳平衡对于科学评价陆地生态系统在全球变化下的源汇效应具有重要意义.基于中国科学院海伦农业生态实验站的长期定位试验,对不同施肥处理下黑土小麦-玉米-大豆轮作体系2005-2007年的作物固碳量与土壤CO2排放通量进行了观测,并对该轮作体系下黑土农田生态系统的碳平衡状况进行了估算.结果表明:在小麦-玉米-大豆轮作体系中,作物固碳量的高低表现为:玉米>大豆>小麦,平均值分别为6 513 kg(C)·hm-2、4 025 kg(C)·hm-2和3 655kg(C)·hm-2,从作物生长季土壤CO2排放总量来看,3种作物以大豆农田生态系统的土壤CO2排放总量最高,平均值达4 062 kg(C)·hm-2;其次为玉米,为3 813 kg(C)·hm-2;而小麦最低,为2 326 kg(C)·hm-2.3种作物轮作下NEP(净生态系统生产力)均为正值,表明黑土农田土壤-作物系统为大气CO2的“汇”,不同作物系统的碳汇强度表现为玉米>小麦>大豆,三者的平均值分别为3 215 kg(C)·hm-2、1643 kg(C)·hm-2和512 kg(C)·hm-2.长期均衡施用氮、磷、钾化肥或氮、磷、钾化肥配施有机肥后,小麦、玉米和大豆农田生态系统的固碳量和土壤CO2排放总量均明显增加,并在氮、磷、钾配施有机肥处理下达到最高.不同的施肥管理措施将改变土壤-植物系统作为大气CO2“汇”的程度,总体表现为化肥均衡施用下NEP值较高,而化肥与有机肥配施下农田生态系统的NEP值较低.%Farmlands are important terrestrial ecosystems with characteristic soil respiration and carbon budget processes. Data from the long-term experiment at Hailun Agricultural Ecology Station of Chinese Academy of Sciences for 2005-2007 were analyzed for the characteristics of crop carbon fixation, soil cumulative CO2 flux and carbon budget in the black soils of wheat-maize-soybean rotation systems

  1. European Union Budget Politics

    DEFF Research Database (Denmark)

    Citi, Manuele

    2015-01-01

    The marginal involvement of the European Union (EU) in redistributive policies and its limited fiscal resources have led to a notable lack of attention by EU scholars towards the EU budget and its dynamics. Yet the nature of the budgetary data and their high usability for statistical analysis make...

  2. NOAA seeks healthy budget

    Science.gov (United States)

    Bush, Susan

    The small, crowded room of the House side of the U.S. Capitol building belied the large budget of $1,611,991,000 requested for Fiscal Year 1992 by the National Oceanic and Atmospheric Administration. John A. Knauss, Undersecretary for Oceans and Atmosphere, U.S. Department of Commerce, delivered his testimony on February 28 before the House Appropriations Subcommittee on Commerce, Justice, and State, the Judiciary and Related Agencies. He told the subcommittee that the budget “attempts to balance the two goals of maintaining NOAA's position as an important science agency and addressing the serious budget problems that the government continues to face.”Climate and global change, modernization of the National Weather Service, and the Coastal Ocean Science program are NOAA's three ongoing, high-priority initiatives that the budget addresses. Also, three additional initiatives—a NOAA-wide program to improve environmental data management, President Bush's multiagency Coastal America initiative, and a seafood safety program administered jointly by NOAA and the Food and Drug Administration—are addressed.

  3. Budgeting in Hard Times.

    Science.gov (United States)

    Parrino, Frank M.

    2003-01-01

    Interviews with school board members and administrators produced a list of suggestions for balancing a budget in hard times. Among these are changing calendars and schedules to reduce heating and cooling costs; sharing personnel; rescheduling some extracurricular activities; and forming cooperative agreements with other districts. (MLF)

  4. Implementing Responsibility Centre Budgeting

    Science.gov (United States)

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  5. Budgeting Academic Space

    Science.gov (United States)

    Harris, Watson

    2011-01-01

    There are many articles about space management, including those that discuss space calculations, metrics, and categories. Fewer articles discuss the space budgeting processes used by administrators to allocate space. The author attempts to fill this void by discussing her administrative experiences with Middle Tennessee State University's (MTSU)…

  6. Implementing Responsibility Centre Budgeting

    Science.gov (United States)

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  7. Pakistan boosts science budget

    Science.gov (United States)

    Harris, Margaret

    2009-08-01

    Government spending on science and technology development in Pakistan will jump by about a quarter in 2009-2010 compared with the previous fiscal year, with big increases planned for nuclear physics and higher education. In late June the country's National Assembly approved a budget of 48.2bn Pakistani rupees (Rs), or about £361m, for new science projects.

  8. Reviewing carbon spiraling approach to understand organic matter movement and transformation in lotic ecosystems

    Directory of Open Access Journals (Sweden)

    Leonardo Kleba Lisboa

    Full Text Available Abstract: Aim Understanding riverine carbon cycling is a major issue for stream ecologists. Over the past 60 years, important advance in carbon dynamics and ecosystem energy flow have been made mainly through the Budget and Metabolism approaches. However, much less focus has been given to the quantification of longitudinal movement of organic matter. The concept “Organic Carbon Spiraling” (SOC was formulated in the early 80s, and represented a substantial advance in the understanding of the longitudinal flow of elements in lotic systems. Methods In this review, we summarize the history behind the SOC concept, cover the major advances at the time of its creation, describe the operational variables and the equation for SOC calculation, and discuss future directions and current applications of this approach. Results/Conclusions We emphasize the need for integrating the C spiraling approach in other regions of the globe, given that measurements are almost exclusive of North America. Such comparative studies can elucidate important drivers of C export, storage and oxidation. Advance in dissolved organic carbon characterization, and improvements in heterotrophic respiration measurements are required to improve SOC accuracy, as well as realistic estimates of benthic stock. With the current interest in examining how lotic systems contribute to regional and global C budgets, we argue that SOC is an effective way to achieve this goal and answer classical questions in stream ecology.

  9. BENTHIC MACROFAUNAL ALIENS IN WILLAPA BAY

    Science.gov (United States)

    Benthic macrofaunal samples were collected at random stations in Willapa Bay, WA, in four habitats [eelgrass (Zostera marina), Atlantic cordgrass (Spartina alterniflora), mud shrimp (Upogebia pugettensis), ghost shrimp (Neotrypaea californiensis)] in 1996 and in seven habitats (Z...

  10. Benthic Habitats of the Florida Keys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The benthic habitats of the Florida Keys were mapped from a series of 450 aerial photographs. Ecologists outlined the boundaries of specific habitat types by...

  11. Benthic studies in south Gujarat estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Govindan, K.; Varshney, P.K.; Desai, B.N.

    Benthic biomass and faunal composition in relation to various environmental conditions of the four South Gujarat estuaries namely the Auranga, Ambika, Purna and Mindola were studied and compared. Mean population density of benthos in Auranga, Ambika...

  12. BENTHIC MACROFAUNAL ALIENS IN WILLAPA BAY

    Science.gov (United States)

    Benthic macrofaunal samples were collected at random stations in Willapa Bay, WA, in four habitats [eelgrass (Zostera marina), Atlantic cordgrass (Spartina alterniflora), mud shrimp (Upogebia pugettensis), ghost shrimp (Neotrypaea californiensis)] in 1996 and in seven habitats (Z...

  13. Feasibility of remote sensing benthic microalgae

    Science.gov (United States)

    Zingmark, R. G.

    1979-01-01

    Results of data analyses from multispectral scanning data are presented. The data was collected in July 1977 for concentration of chlorophyll in benthic microalgae (mainly diatoms) on an estuary mudflat.

  14. Stable-isotope analysis of a deep-sea benthic-fish assemblage: evidence of an enriched benthic food web.

    Science.gov (United States)

    Boyle, M D; Ebert, D A; Cailliet, G M

    2012-04-01

    In this study, fishes and invertebrates collected from the continental slope (1000 m) of the eastern North Pacific Ocean were analysed using stable-isotope analysis (SIA). Resulting trophic positions (T(P) ) were compared to known diets and habitats from the literature. Dual isotope plots indicated that most species groups (invertebrates and fishes) sorted as expected along the carbon and nitrogen axes, with less intraspecific variability than interspecific variability. Results also indicated an isotopically distinct benthic and pelagic food web, as the benthic food web was more enriched in both nitrogen and carbon isotopes. Trophic positions from SIA supported this finding, resulting in the assignment of fishes to different trophic positions from those expected based on published dietary information. These differences can be explained largely by the habitat of the prey and the percentage of the diet that was scavenged. A mixing model estimated dietary contributions of prey similar to those of the known diet of Bathyraja trachura from stomach-content analysis (SCA). Linear regressions indicated that trophic positions calculated from SIA and SCA, when plotted against B. trachura total length for 32 individuals, exhibited similar variation and patterns. Only the T(P) from SCA yielded significant results (stomach content: P 0·05). © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  15. Physiological controls on seawater uptake and calcification in the benthic foraminifer Ammonia tepida

    Directory of Open Access Journals (Sweden)

    G. Nehrke

    2009-11-01

    Full Text Available To analyze the relation between seawater uptake and calcification, we incubated juveniles of the benthic foraminifer Ammonia tepida with various fluorescent probes and visualised them afterwards with confocal laser scanning microscopy. Vesicle membranes, Ca ions and vacuole fluids were followed with various tracers and showed for the first time that endocytosis of seawater is part of the calcification process in Ammonia tepida. Data on the intracellular Ca ion cycling allowed for calculating a preliminary cellular Ca budget during foraminiferal calcification. This showed that the free calcium involved in the production of a new chamber cannot be sufficient and suggests that foraminifera may precipitate their calcite from an amorphous precursor.

  16. The global methane budget 2000-2012

    Science.gov (United States)

    Saunois, Marielle; Bousquet, Philippe; Poulter, Ben; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander; Janssens-Maenhout, Greet; Tubiello, Francesco N.; Castaldi, Simona; Jackson, Robert B.; Alexe, Mihai; Arora, Vivek K.; Beerling, David J.; Bergamaschi, Peter; Blake, Donald R.; Brailsford, Gordon; Brovkin, Victor; Bruhwiler, Lori; Crevoisier, Cyril; Crill, Patrick; Covey, Kristofer; Curry, Charles; Frankenberg, Christian; Gedney, Nicola; Höglund-Isaksson, Lena; Ishizawa, Misa; Ito, Akihiko; Joos, Fortunat; Kim, Heon-Sook; Kleinen, Thomas; Krummel, Paul; Lamarque, Jean-François; Langenfelds, Ray; Locatelli, Robin; Machida, Toshinobu; Maksyutov, Shamil; McDonald, Kyle C.; Marshall, Julia; Melton, Joe R.; Morino, Isamu; Naik, Vaishali; O'Doherty, Simon; Parmentier, Frans-Jan W.; Patra, Prabir K.; Peng, Changhui; Peng, Shushi; Peters, Glen P.; Pison, Isabelle; Prigent, Catherine; Prinn, Ronald; Ramonet, Michel; Riley, William J.; Saito, Makoto; Santini, Monia; Schroeder, Ronny; Simpson, Isobel J.; Spahni, Renato; Steele, Paul; Takizawa, Atsushi; Thornton, Brett F.; Tian, Hanqin; Tohjima, Yasunori; Viovy, Nicolas; Voulgarakis, Apostolos; van Weele, Michiel; van der Werf, Guido R.; Weiss, Ray; Wiedinmyer, Christine; Wilton, David J.; Wiltshire, Andy; Worthy, Doug; Wunch, Debra; Xu, Xiyan; Yoshida, Yukio; Zhang, Bowen; Zhang, Zhen; Zhu, Qiuan

    2016-12-01

    The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (˜ biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). For the 2003-2012 decade, global methane emissions are estimated by top-down inversions at 558 Tg CH4 yr-1, range 540-568. About 60 % of global emissions are anthropogenic (range 50-65 %). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP scenarios

  17. Benthic buffers and boosters of ocean acidification on coral reefs

    Directory of Open Access Journals (Sweden)

    K. R. N. Anthony

    2013-07-01

    Full Text Available Ocean acidification is a threat to marine ecosystems globally. In shallow-water systems, however, ocean acidification can be masked by benthic carbon fluxes, depending on community composition, seawater residence time, and the magnitude and balance of net community production (NCP and calcification (NCC. Here, we examine how six benthic groups from a coral reef environment on Heron Reef (Great Barrier Reef, Australia contribute to changes in the seawater aragonite saturation state (Ωa. Results of flume studies using intact reef habitats (1.2 m by 0.4 m, showed a hierarchy of responses across groups, depending on CO2 level, time of day and water flow. At low CO2 (350–450 μatm, macroalgae (Chnoospora implexa, turfs and sand elevated Ωa of the flume water by around 0.10 to 1.20 h−1 – normalised to contributions from 1 m2 of benthos to a 1 m deep water column. The rate of Ωa increase in these groups was doubled under acidification (560–700 μatm and high flow (35 compared to 8 cm s−1. In contrast, branching corals (Acropora aspera increased Ωa by 0.25 h−1 at ambient CO2 (350–450 μatm during the day, but reduced Ωa under acidification and high flow. Nighttime changes in Ωa by corals were highly negative (0.6–0.8 h−1 and exacerbated by acidification. Calcifying macroalgae (Halimeda spp. raised Ωa by day (by around 0.13 h−1, but lowered Ωa by a similar or higher amount at night. Analyses of carbon flux contributions from benthic communities with four different compositions to the reef water carbon chemistry across Heron Reef flat and lagoon indicated that the net lowering of Ωa by coral-dominated areas can to some extent be countered by long water-residence times in neighbouring areas dominated by turfs, macroalgae and carbonate sand.

  18. Major role of marine vegetation on the oceanic carbon cycle

    Directory of Open Access Journals (Sweden)

    C. M. Duarte

    2005-01-01

    Full Text Available The carbon burial in vegetated sediments, ignored in past assessments of carbon burial in the ocean, was evaluated using a bottom-up approach derived from upscaling a compilation of published individual estimates of carbon burial in vegetated habitats (seagrass meadows, salt marshes and mangrove forests to the global level and a top-down approach derived from considerations of global sediment balance and a compilation of the organic carbon content of vegeatated sediments. Up-scaling of individual burial estimates values yielded a total carbon burial in vegetated habitats of 111 Tmol C y-1. The total burial in unvegetated sediments was estimated to be 126 Tg C y-1, resulting in a bottom-up estimate of total burial in the ocean of about 244 Tg C y-1, two-fold higher than estimates of oceanic carbon burial that presently enter global carbon budgets. The organic carbon concentrations in vegetated marine sediments exceeds by 2 to 10-fold those in shelf/deltaic sediments. Top-down recalculation of ocean sediment budgets to account for these, previously neglected, organic-rich sediments, yields a top-down carbon burial estimate of 216 Tg C y-1, with vegetated coastal habitats contributing about 50%. Even though vegetated carbon burial contributes about half of the total carbon burial in the ocean, burial represents a small fraction of the net production of these ecosystems, estimated at about 3388 Tg C y-1, suggesting that bulk of the benthic net ecosystem production must support excess respiration in other compartments, such as unvegetated sediments and the coastal pelagic compartment. The total excess organic carbon available to be exported to the ocean is estimated at between 1126 to 3534 Tg C y-1, the bulk of which must be respired in the open ocean. Widespread loss of vegetated coastal habitats must have reduced carbon burial in the ocean by about 30 Tg C y-1, identifying the destruction of these ecosystems as an important loss of CO

  19. Nutrient budget in ecosystems

    Science.gov (United States)

    Titlyanova, A. A.

    2007-12-01

    Methods to calculate nutrient budgets in forest and grassland ecosystems are analyzed on the basis of a large number of published materials and original data. New estimates of the belowground production in forest ecosystems with due account for the growth of fine roots are suggested. Nutrient retranslocation from senescent plant tissues to growing plant tissues and nutrient leaching from the forest canopy are discussed. The budgets of major nutrients (N, P, K, and Ca) in tundra, forest, and steppe ecosystems are calculated. Nutrient cycles in two forest ecosystems—a coniferous stand dominated by Picea abies and a broad-leaved stand dominated by Quercus robur—are analyzed in detail. It is shown that the more intensive turnover of nutrients in the oak stand is also characterized by a more closed character of the nutrient cycles.

  20. See-Through Budgets

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A more transparent budget is needed to keep track of fiscal expenditures Just what was the massive 3 trillion yuan in revenue collected by the Chinese Government last fiscal year used for? This is a big question swirling around the conversation tables of a nation eager for answers. Most Chinese people are now increasingly aware of the right to know how governments at all levels spend their money and are

  1. The Incredible Shrinking Budget

    Science.gov (United States)

    T.H.E. Journal, 2013

    2013-01-01

    If district technology leaders had a nickel for every time they heard the phrase "the new normal," they'd have all the money they need to run their IT departments. In an effort to help readers think about their budgets in creative and practical ways, "T.H.E. Journal" and the Consortium for School Networking (CoSN) recently convened a panel of CTOs…

  2. Shoreline urbanization interrupts allochthonous subsidies to a benthic consumer over a gradient of lake size.

    Science.gov (United States)

    Larson, Eric R; Olden, Julian D; Usio, Nisikawa

    2011-08-23

    The role of resource subsidies across ecosystem boundaries has emerged as an important concept in contemporary ecology. For lake ecosystems, this has led to interest in quantifying the contribution of terrestrial allochthonous carbon to aquatic secondary production. An inverse relationship between habitat area and the role of allochthonous subsidies has been documented on marine islands and assumed for lakes, yet there have been no tests of this pattern among benthic (lake bottom) consumers. Here, we used carbon stable isotopes to trace terrestrial allochthonous and benthic autochthonous carbon use by the crayfish Pacifastacus leniusculus over a gradient of lake area, productivity and urbanization. Consistent with findings from terrestrial islands, habitat size dictated the importance of allochthonous subsidies, as P. leniusculus transitioned from using predominantly terrestrial carbon in small lakes to an increased reliance on autochthonous production in larger lakes. However, shoreline urbanization interacted with this pattern, particularly for small lakes where greater urbanization resulted in reduced use of allochthonous resources. As such, we provide, to our knowledge, the first confirmation of the predicted relationship between habitat size and importance of allochthonous subsidies to lake benthic consumers, but found that urbanization can interfere with this pattern.

  3. Post-depositional alteration of benthic foraminifera in a methane seep environment

    Science.gov (United States)

    Schneider, Andrea; Cremiere, Antoine; Panieri, Giuliana; Lepland, Aivo; Knies, Jochen

    2016-04-01

    Benthic foraminifera tests from the sediment cores taken from the Vestnesa Ridge, one of the northernmost known marine methane hydrate reservoir, were studied for their visual appearance, mineral and stable carbon isotopic composition in order to explore their indicator potential in a methane seep environment. The Vestnesa Ridge is a sediment drift located in 1200m water depth at 79°N at Svalbard's northwestern continental margin. Observations of gas flares originating from pockmarks that are aligned along the crest of the ridge show ongoing methane emission. A distinct sediment layer containing a fossilized assemblage of chemosynthetic bivalves indicates methane seepage activity at least in the late Pleistocene. We have examined the state of preservation and geochemical characteristics of foraminifera tests from this bivalve shell horizon. Tests of the benthic foraminifera species Cassidulina neoteretis display a variable degree of post-depositional alteration and formation of diagenetic carbonate overgrowths on calcitic primary tests. Using binoculars, scanning electron microscope imagery and energy dispersive x-ray spectroscopy, we distinguish visually and mineralogically different diagenetic phases on the external and internal test surfaces. Pristine and smooth test surfaces act as nucleation templates for precipitation of authigenic Mg-calcite crystals causing complete filling of chambers and encrustation of the external test surfaces. The presence of Mg-calcite indicates the overgrowth is precipitating in sulfate-poor sediments. In addition to benthic foraminifera, we have studied the mineralogical and stable carbon and oxygen isotope composition of authigenic carbonate nodules found in the bivalve shell horizon. The mineralogical nature of the carbonates and overgrowths on the foraminifera tests were found to be identical. The δ13C value of the carbonate nodules is as low as -32.3‰ indicating their methane-derived origin. Authigenic carbonate coated

  4. Assessing the suitability of benthic foraminiferal morpho-groups to reconstruct paleomonsoon from Bay of Bengal

    Science.gov (United States)

    Manasa, M.; Saraswat, Rajeev; Nigam, Rajiv

    2016-04-01

    Temporal changes in benthic foraminiferal morpho-groups were suggested as an effective proxy to reconstruct past monsoon intensity from the Arabian Sea. Here, in order to test the applicability of temporal variation in morpho-groups to reconstruct past monsoon intensity from the Bay of Bengal, we have documented recent benthic foraminiferal distribution from the continental shelf region of the northwestern Bay of Bengal. Based on the external morphology, benthic foraminifera were categorized into rounded symmetrical (RSBF) and angular asymmetrical benthic foraminifera (AABF). Additionally, a few other dominant groups were also identified based on test composition (agglutinated, calcareous) and abundance (Asterorotalids and Nonions). The relative abundance of each group was compared with the ambient physico-chemical conditions, including dissolved oxygen, organic matter, salinity and temperature. We report that the RSBF are abundant in comparatively warm and well oxygenated waters of low salinity, suggesting a preference for high energy environment, whereas AABF dominate relatively cold, hypersaline deeper waters with low dissolved oxygen, indicating a low energy environment. The agglutinated foraminifera, Asterorotalids and Nonions dominate shallow water, low salinity regions, whereas the calcareous benthic foraminiferal abundance increases away from the riverine influx regions. Food availability, as estimated from organic carbon abundance in sediments, has comparatively less influence on faunal distribution in the northwestern Bay of Bengal, as compared to dissolved oxygen, temperature and salinity. We conclude that the factors associated with freshwater influx affect the distribution of benthic foraminiferal morpho-groups in the northwestern Bay of Bengal and thus it can be used to reconstruct past monsoon intensity from the Bay of Bengal.

  5. Benthic Foraminifera, Food in the Deep Sea, and Limits to Bentho-Pelagic Coupling

    Science.gov (United States)

    Thomas, E.; Boscolo-Galazzo, F.; Arreguin-Rodrigu, G. J.; Ortiz, S.; Alegret, L.

    2015-12-01

    The deep-sea is the largest habitat on Earth, contains highly diverse biota, but is very little known. Many of its abundant benthic biota (e.g., nematodes) are not preserved in the fossil record. Calcareous and agglutinated benthic foraminifera (unicellular eukaryotes, Rhizaria; efficient dispersers) and ostracodes (Animalia, Crustacea; non-efficient dispersers) are the most common organisms providing a fossil record of deep-sea environments. Very little food is supplied to the deep-sea, because organic matter produced by photosynthesis is largely degraded before it arrives at the seafloor. Only a few % of organic matter is carried to the ocean bottom by 'marine snow', with its particle size and behavior in the water column controlled by surface ecosystem structure, including type of dominant primary producers (diatoms, cyanobacteria). Food supply and its seasonality are generally seen as the dominant control on benthic assemblages (combined with oxygenation), providing bentho-pelagic coupling between primary and benthic productivity. Benthic foraminiferal assemblages (composition and density) thus are used widely to estimate past productivity, especially during episodes of global climate change, ocean acidification, and mass extinction of primary producers. We show that some environmental circumstances may result in interrupting bentho-pelagic coupling, e.g. through lateral supply of organic matter along continental margins (adding more refractory organic matter), through trophic focusing and/or fine particle winnowing on seamounts (giving an advantage to suspension feeders), and through carbonate undersaturation (giving advantage to infaunal over epifaunal calcifyers). In addition, increased remineralization of organic matter combined with increased metabolic rates may cause assemblages to reflect more oligotrophic conditions at stable primary productivity during periods of global warming. As a result, benthic foraminiferal accumulation rates must be carefully

  6. TRADITIONAL BUDGETING VERSUS BEYOND BUDGETING: A LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    CARDOS ILDIKO REKA

    2014-07-01

    Full Text Available Budgets are an important part of the business environment since 1920 and are considered to be the key drivers and evaluators of managerial performance; and the key elements for planning and control. Budgets are the most powerful tool for management control; they can play an essential role in the organization’s power politics because it can increase the power and authority of top management and limit the autonomy of lower-level managers. Besides its advantages traditional budgeting presents disadvantages also. In recent years criticism towards traditional budgeting has increased. The basis of this criticism is that traditional budgeting is a relic of the past; it prevents reactions to changes in the market, it cannot keep up with the changes and requirements of today’s business world and it isn’t useful for business management. In order to eliminate criticism researchers and practitioners have developed more systematic and alternative concepts of budgeting that suits better for the needs of the modern business environment. Beyond budgeting, better budgeting, rolling forecasts, activity-based budgeting are the main alternatives developed in the last years. From the mentioned alternatives this article examines only beyond budgeting. Our paper discusses how budgeting has evolved into its current state, before examining why this universal technique has come under such heavy criticism of late. The paper is a literature analysis, it contributes to the existing managerial accounting literature and it is structured as follows. In the first part the background and evolution of budgeting is presented, followed by the analysis of related theories in traditional budgeting, emphasizing both the advantages and disadvantages of traditional budgeting. The second part of the paper continues with the discussion about alternative budgeting methods highlighting pros and cons of alternative methods, especially beyond budgeting. In the third part conducted

  7. Benthic-Pelagic Coupling in Biogeochemical and Climate Models: Existing Approaches, Recent developments and Roadblocks

    Science.gov (United States)

    Arndt, Sandra

    2016-04-01

    Marine sediments are key components in the Earth System. They host the largest carbon reservoir on Earth, provide the only long term sink for atmospheric CO2, recycle nutrients and represent the most important climate archive. Biogeochemical processes in marine sediments are thus essential for our understanding of the global biogeochemical cycles and climate. They are first and foremost, donor controlled and, thus, driven by the rain of particulate material from the euphotic zone and influenced by the overlying bottom water. Geochemical species may undergo several recycling loops (e.g. authigenic mineral precipitation/dissolution) before they are either buried or diffuse back to the water column. The tightly coupled and complex pelagic and benthic process interplay thus delays recycling flux, significantly modifies the depositional signal and controls the long-term removal of carbon from the ocean-atmosphere system. Despite the importance of this mutual interaction, coupled regional/global biogeochemical models and (paleo)climate models, which are designed to assess and quantify the transformations and fluxes of carbon and nutrients and evaluate their response to past and future perturbations of the climate system either completely neglect marine sediments or incorporate a highly simplified representation of benthic processes. On the other end of the spectrum, coupled, multi-component state-of-the-art early diagenetic models have been successfully developed and applied over the past decades to reproduce observations and quantify sediment-water exchange fluxes, but cannot easily be coupled to pelagic models. The primary constraint here is the high computation cost of simulating all of the essential redox and equilibrium reactions within marine sediments that control carbon burial and benthic recycling fluxes: a barrier that is easily exacerbated if a variety of benthic environments are to be spatially resolved. This presentation provides an integrative overview of

  8. Comparative biomass structure and estimated carbon flow in food webs in the deep Gulf of Mexico

    Science.gov (United States)

    Rowe, Gilbert T.; Wei, Chihlin; Nunnally, Clifton; Haedrich, Richard; Montagna, Paul; Baguley, Jeffrey G.; Bernhard, Joan M.; Wicksten, Mary; Ammons, Archie; Briones, Elva Escobar; Soliman, Yousra; Deming, Jody W.

    2008-12-01

    A budget of the standing stocks and cycling of organic carbon associated with the sea floor has been generated for seven sites across a 3-km depth gradient in the NE Gulf of Mexico, based on a series of reports by co-authors on specific biotic groups or processes. The standing stocks measured at each site were bacteria, Foraminifera, metazoan meiofauna, macrofauna, invertebrate megafauna, and demersal fishes. Sediment community oxygen consumption (SCOC) by the sediment-dwelling organisms was measured at each site using a remotely deployed benthic lander, profiles of oxygen concentration in the sediment pore water of recovered cores and ship-board core incubations. The long-term incorporation and burial of organic carbon into the sediments has been estimated using profiles of a combination of stable and radiocarbon isotopes. The total stock estimates, carbon burial, and the SCOC allowed estimates of living and detrital carbon residence time within the sediments, illustrating that the total biota turns over on time scales of months on the upper continental slope but this is extended to years on the abyssal plain at 3.6 km depth. The detrital carbon turnover is many times longer, however, over the same depths. A composite carbon budget illustrates that total carbon biomass and associated fluxes declined precipitously with increasing depth. Imbalances in the carbon budgets suggest that organic detritus is exported from the upper continental slope to greater depths offshore. The respiration of each individual "size" or functional group within the community has been estimated from allometric models, supplemented by direct measurements in the laboratory. The respiration and standing stocks were incorporated into budgets of carbon flow through and between the different size groups in hypothetical food webs. The decline in stocks and respiration with depth were more abrupt in the larger forms (fishes and megafauna), resulting in an increase in the relative predominance of

  9. Benthic buffers and boosters of ocean acidification on coral reefs

    Directory of Open Access Journals (Sweden)

    K. R. N. Anthony

    2013-02-01

    Full Text Available Ocean acidification is a threat to marine ecosystems globally. In shallow-water systems, however, ocean acidification can be masked by benthic carbon fluxes, depending on community composition, seawater residence time, and the magnitude and balance of net community production (pn and calcification (gn. Here, we examine how six benthic groups from a coral reef environment on Heron Reef (Great Barrier Reef, Australia contribute to changes in seawater aragonite saturation state (Ωa. Results of flume studies showed a hierarchy of responses across groups, depending on CO2 level, time of day and water flow. At low CO2 (350–450 μatm, macroalgae (Chnoospora implexa, turfs and sand elevated Ωa of the flume water by around 0.10 to 1.20 h−1 – normalised to contributions from 1 m2 of benthos to a 1 m deep water column. The rate of Ωa increase in these groups was doubled under acidification (560–700 μatm and high flow (35 compared to 8 cm s−1. In contrast, branching corals (Acropora aspera increased Ωa by 0.25 h−1 at ambient CO2 (350–450 μatm during the day, but reduced Ωa under acidification and high flow. Nighttime changes in Ωa by corals were highly negative (0.6–0.8 h−1 and exacerbated by acidification. Calcifying macroalgae (Halimeda spp. raised Ωa by day (by around 0.13 h−1, but lowered Ωa by a similar or higher amount at night. Analyses of carbon flux contributions from four different benthic compositions to the reef water carbon chemistry across Heron Reef flat and lagoon indicated that the net lowering of Ωa by coral-dominated areas can to some extent be countered by long water residence times in neighbouring areas dominated by turfs, macroalgae and potentially sand.

  10. Benthic phosphorus cycling in the Peruvian oxygen minimum zone

    Science.gov (United States)

    Lomnitz, Ulrike; Sommer, Stefan; Dale, Andrew W.; Löscher, Carolin R.; Noffke, Anna; Wallmann, Klaus; Hensen, Christian

    2016-03-01

    Oxygen minimum zones (OMZs) that impinge on continental margins favor the release of phosphorus (P) from the sediments to the water column, enhancing primary productivity and the maintenance or expansion of low-oxygen waters. A comprehensive field program in the Peruvian OMZ was undertaken to identify the sources of benthic P at six stations, including the analysis of particles from the water column, surface sediments, and pore fluids, as well as in situ benthic flux measurements. A major fraction of solid-phase P was bound as particulate inorganic P (PIP) both in the water column and in sediments. Sedimentary PIP increased with depth in the sediment at the expense of particulate organic P (POP). The ratio of particulate organic carbon (POC) to POP exceeded the Redfield ratio both in the water column (202 ± 29) and in surface sediments (303 ± 77). However, the POC to total particulate P (TPP = POP + PIP) ratio was close to Redfield in the water column (103 ± 9) and in sediment samples (102 ± 15). This suggests that the relative burial efficiencies of POC and TPP are similar under low-oxygen conditions and that the sediments underlying the anoxic waters on the Peru margin are not depleted in P compared to Redfield. Benthic fluxes of dissolved P were extremely high (up to 1.04 ± 0.31 mmol m-2 d-1), however, showing that a lack of oxygen promotes the intensified release of dissolved P from sediments, whilst preserving the POC / TPP burial ratio. Benthic dissolved P fluxes were always higher than the TPP rain rate to the seabed, which is proposed to be caused by transient P release by bacterial mats that had stored P during previous periods when bottom waters were less reducing. At one station located at the lower rim of the OMZ, dissolved P was taken up by the sediments, indicating ongoing phosphorite formation. This is further supported by decreasing porewater phosphate concentrations with sediment depth, whereas solid-phase P concentrations were comparatively

  11. BUDGET AND BUDGET EXECUTION IN THE NORTHWEST REGION OF ROMANIA

    Directory of Open Access Journals (Sweden)

    IOAN BATRANCEA

    2013-07-01

    Full Text Available The budget is a tool multiannual financial forecasting both at micro and macro level. In this sense, regional and local government budget is a financial instrument that connects resources to use local funds in order to ensure the prosperity of the community concerned. Construction and especially budget execution highlights the effectiveness of local and regional government. Using a system of indicators correlated reveals income, expenditure and budgetary outturn.

  12. Relationship between sedimentation rates and benthic impact on Maërl beds derived from fish farming in the Mediterranean.

    Science.gov (United States)

    Sanz-Lázaro, Carlos; Belando, María Dolores; Marín-Guirao, Lázaro; Navarrete-Mier, Francisco; Marín, Arnaldo

    2011-02-01

    The aim of this work was to study the dispersion of particulate wastes derived from marine fish farming and correlate the data with the impact on the seabed. Carbon and nutrients were correlated with the physico-chemical parameters of the sediment and the benthic community structure. The sedimentation rates in the benthic system were 1.09, 0.09 and 0.13 g m⁻² day⁻¹ for particulate organic carbon (POC), particulate organic nitrogen (PON) and total phosphorus (TP), respectively. TP was a reliable parameter for establishing the spatial extent of the fish farm particulate wastes. Fish farming was seen to influence not only physico-chemical and biological parameters but also the functioning of the ecosystem from a trophic point of view, particularly affecting the grazers and the balance among the trophic groups. POC, PON and TP sedimentation dynamics reflected the physico-chemical status of the sediment along the distance gradient studied, while their impact on the benthic community extended further. Therefore, the level of fish farm impact on the benthic community might be underestimated if it is assessed by merely taking into account data obtained from waste dispersion rates. The benthic habitat beneath the fish farm, Maërl bed, was seen to be very sensitive to aquaculture impact compared with other unvegetated benthic habitats, with an estimated POC-carrying capacity to maintain current diversity of 0.087 g C m⁻² day⁻¹ (only 36% greater than the basal POC input). Environmental protection agencies should define different aquaculture waste load thresholds for different benthic communities affected by finfish farming, according to their particular degree of sensitivity, in order to maintain natural ecosystem functions.

  13. Spatial distribution maps for benthic communities

    DEFF Research Database (Denmark)

    Sørensen, Per S.

    1999-01-01

    simulation, Markov random fields and Boolean models. Geostatistical simulation provides a means of assessing the variability of random field functionals such as the estimated distribution area of a benthic species. The Markov random field allows the spatial distribution of the benthic communities......The application of hydroacoustic measurements for preparation of spatial distribution maps of benthic communities is reported. For the present study common mussels (Mytilus edulis), neptune grass (Posidonia oceanica) and Cymodocea nodosa, serving as canonical species of many European marine....... The estimates of variability obtained for estimated distribution areas with the two approaches compare satisfactorily. The Boolean models are suggested as a point of departure for embedding models of spatial patterns on the minor scales of observations to be used in up-scaling approaches to enhance the quality...

  14. Are benthic fluxes important for the availability of Si in the Gulf of Finland?

    Science.gov (United States)

    Tallberg, Petra; Heiskanen, Anna-Stiina; Niemistö, Juha; Hall, Per O. J.; Lehtoranta, Jouni

    2017-07-01

    We estimated the efflux of dissolved silicon (DSi) from sediments in the Gulf of Finland and compared it to sedimentation fluxes, burial of Si and existing data on Si loading and stocks, reassessing the reliability of existing Si budgets. Benthic fluxes of DSi measured in situ and in vitro were several times higher than estimates from diffusion calculations. The spatial variability in the open Gulf of Finland was relatively small, while both very high and low fluxes were measured from coastal areas. Fluxes were highest in late summer and lowest in early spring. In our re-assessed budget we present a new lower estimate for Si burial in the sediments, ca. 6 Gmol a- 1 and show that more than half of the sedimentation flux of Si is released back into the water column. Changes in the efficiency of internal DSi recycling may thus affect the prevalence of siliceous phytoplankton within the ecosystem, and the diatom spring bloom may be regulated by the functioning of this internal recycling pump. We also show that the seasonal variation in benthic DSi fluxes and dissolved phosphate fluxes is similar, and that a tentative connection between hypoxia and high DSi efflux exists.

  15. Reforming the EU Budget

    DEFF Research Database (Denmark)

    Citi, Manuele

    The marginal involvement of the EU in redistributive policies and its limited fiscal resources have led to a lack of attention to the EU budget and its determinants. In this paper I analyse an original dataset containing yearly data on the main macrocategories of expenditure and how they have...... changed over the last three decades (1984-2013). Using time series analysis, I find that the ability to form winning coalitions in the Council, the ideological position of the co-legislators, and some ‘structuring events’ - like the adoption of the Multiannual Financial Framework and the accession...

  16. Marketing with limited budget

    OpenAIRE

    Smirnova, Daria

    2017-01-01

    The purpose of this research-based thesis was to get an idea how managers of two small resembling hotels of a specific region deal with marketing process with a limited budget. In addition, the aim of the thesis was to examine if hotel managers who were interviewed perceive marketing only in the way of ‘promotion’ rather than marketing research, marketing mix and marketing environment theories. It was also found out if hotel managers of those hotels consider marketing as a key to successful h...

  17. Environmental budget and policy goal

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sang Hwan [Korea Environment Institute, Seoul (Korea)

    1998-12-01

    The assigned budget for environmental sector is quite insufficient to meet enormous environmental demand. Under this circumstance, there is only one way to solve environmental problems efficiently, i.e. to use a given budget efficiently. Therefore, the study on efficient utilization of a given environmental invested finance is needed by customizing a diagnosis of present condition on the operation of environmental budget and environmental investment analysis. In this respect, an entire national budget of 1999 and environmental budget were analyzed in this study. By analyzing economic efficiency of sewage disposal program, integrated septic tank system, VOC regulation, incinerator construction program, food waste disposal program, and recycling program, an efficient budget policy was presented. 19 refs., 18 figs., 169 tabs.

  18. Appraisal of laboratory culture experiments on benthic foraminifera to assess/develop paleoceanographic proxies

    Digital Repository Service at National Institute of Oceanography (India)

    Linshy, V.N.; Rana, S.S.; Kurtarkar, S.; Saraswat, R.; Nigam, R.

    through ages Though laboratory maintenance of benthic foraminifera started from the first half of the 19 th century and number of studies were published during the later half of the 19 th century, it was not until the mid of 20 th century... structure analysis. ms et al. 91 1981 Identified significant disequilibrium in carbon and oxygen isotopic fractionation in Heterostegina depressa and attributed it to the vital effects that varied with changing light intensity and age. y 139...

  19. Collection assessment and acquisitions budgets

    CERN Document Server

    Lee, Sul H

    2013-01-01

    This invaluable new book contains timely information about the assessment of academic library collections and the relationship of collection assessment to acquisition budgets. The rising cost of information significantly influences academic libraries'abilities to acquire the necessary materials for students and faculty, and public libraries'abilities to acquire material for their clientele. Collection Assessment and Acquisitions Budgets examines different aspects of the relationship between the assessment of academic library collections and the management of library acquisition budgets. Librar

  20. Influence of sea squirt (Halocynthia roretzi) aquaculture on benthic-pelagic coupling in coastal waters: A study of the South Sea in Korea

    Science.gov (United States)

    Lee, Jae Seong; Kim, Sung-Han; Kim, Yong-Tae; Hong, Sok Jin; Han, Jeong Hee; Hyun, Jung-Ho; Shin, Kyung-Hoon

    2012-03-01

    The influence of sea squirt aquaculture on benthic-pelagic coupling was evaluated in semi-enclosed Korean coastal waters with an in situ benthic chamber and results show for the first time that suspended sea squirt cultures play an important role in benthic-pelagic coupling in the coastal zone. Measurements of primary production, vertical particulate fluxes, and benthic fluxes were made at two stations, a sea squirt (Halocynthia roretzi) farm (SSF) and an area of organic-matter-enriched sediment in Jinhae Bay. The vertical material fluxes of organic carbon, nitrogen, and biogenic silicate (BSi) were significantly higher at SSF than in Jinhae Bay, indicating massive biodeposits in the surface sediments at SSF. The organic carbon oxidation rates (Cox) were estimated after correction for CaCO3 dissolution. The average Cox at SSF (204 mmol C m-2 d-1) was significantly higher than that in the organic-enriched Jinhae Bay sediment (77 mmol C m-2 d-1). The organic carbon burial fluxes were determined using vertical profiles of organic carbon of up to 30 cm and the sedimentation rate calculated from the excess 210Pb distribution. At both stations, ˜95% of the settled organic carbon was oxidized and only ˜5% was buried in the deep sediment layer. The benthic fluxes of dissolved inorganic nitrogen and phosphate at SSF were 2-12 times higher than in Jinhae Bay, corresponding to 85%, and 270%, respectively, of the requirements for primary production.