Continental shelf pump

Continental shelf pump

In oceanic biogeochemistry, the continental shelf pump is proposed to operate in the shallow waters of the continental shelves, acting as a mechanism to transport carbon (as either dissolved or particulate material) from surface waters to the interior of the adjacent deep ocean.[1]

Contents

Overview

Originally formulated by Tsunogai et al. (1999),[1] the pump is believed to occur where the solubility and biological pumps interact with a local hydrography that feeds dense water from the shelf floor into sub-surface (at least subthermocline) waters in the neighbouring deep ocean. Tsunogai et al.'s (1999)[1] original work focused on the East China Sea, and the observation that, averaged over the year, its surface waters represented a sink for carbon dioxide. This observation was combined with others of the distribution of dissolved carbonate and alkalinity and explained as follows :

  • the shallowness of the continental shelf restricts convection of cooling water
  • as a consequence, cooling is greater for continental shelf waters than for neighbouring open ocean waters
  • this leads to the production of relatively cool and dense water on the shelf
  • the cooler waters promote the solubility pump and lead to an increased storage of dissolved inorganic carbon
  • this extra carbon storage is augmented by the increased biological production characteristic of shelves[2]
  • the dense, carbon-rich shelf waters sink to the shelf floor and enter the sub-surface layer of the open ocean via isopycnal mixing

Significance

Based on their measurements of the CO2 flux over the East China Sea (35 g C m−2 y−1), Tsunogai et al. (1999)[1] estimated that the continental shelf pump could be responsible for an air-to-sea flux of approximately 1 Gt C y−1 over the world's shelf areas. Given that observational[3] and modelling[4] of anthropogenic emissions of CO2 estimates suggest that the ocean is currently responsible for the uptake of approximately 2 Gt C y−1, and that these estimates are poor for the shelf regions, the continental shelf pump may play an important role in the ocean's carbon cycle.

One caveat to this calculation is that the original work was concerned with the hydrography of the East China Sea, where cooling plays the dominant role in the formation of dense shelf water, and that this mechanism may not apply in other regions. However, it has been suggested[5] that other processes may drive the pump under different climatic conditions. For instance, in polar regions, the formation of sea-ice results in the extrusion of salt that may increase seawater density. Similarly, in tropical regions, evaporation may increase local salinity and seawater density.

The strong sink of CO2 at temperate latitudes reported by Tsunogai et al. (1999)[1] was later confirmed in the Gulf of Biscay,[6] the Middle Atlantic Bight[7] and the North Sea.[8] On the other hand, in the sub-tropical South Atlantic Bight reported a source of CO2 to the atmosphere.[9]

Recently, work[10][11] has compiled and scaled available data on CO2 fluxes in coastal environments, and shown that globally marginal seas act as a significant CO2 sink (-1.6 mol C m−2 y−1; -0.45 Gt C y−1) in agreement with previous estimates. However, the global sink of CO2 in marginal seas could be almost fully compensated by the emission of CO2 (+11.1 mol C m−2 y−1; +0.40 Gt C y−1) from the ensemble of near-shore coastal ecosystems, mostly related to the emission of CO2 from estuaries (0.34 Gt C y−1).

An interesting application of this work has been examining the impact of sea level rise over the last de-glacial transition on the global carbon cycle. During the last glacial maximum sea level was some 120 m lower than today. As sea level rose the surface area of the shelf seas grew and in consequence the strength of the shelf sea pump should increase. Rippeth et al (2008) examine the consequences of this sea level rise on the strength of the shelf sea pump.

Rippeth TP, Scourse JD, Uehara, K (2008). Impact of sea-level rise over the last deglacial transition on the strength of the continental shelf CO(2) pump, GEOPHYSICAL RESEARCH LETTERS, 35(24), L24604 DOI: 10.1029/2008GL035880

  1. ^ a b c d e Tsunogai, S.; Watanabe, S.; Sato, T. (1999). "Is there a "continental shelf pump" for the absorption of atmospheric CO2". Tellus, Ser. B 51 (3): 701–712. doi:10.1034/j.1600-0889.1999.t01-2-00010.x. 
  2. ^ Wollast, R. (1998). Evaluation and comparison of the global carbon cycle in the coastal zone and in the open ocean, p. 213-252. In K. H. Brink and A. R. Robinson (eds.), The Global Coastal Ocean. John Wiley & Sons.
  3. ^ Takahashi, T.; Sutherland, S. C.; Sweeney, C.; Poisson, A.; Metzl, N.; Tilbrook, B.; Bates, N.; Wanninkhof, R. et al. (2002). "Global sea-air CO2 flux based on climatological surface ocean pCO2, and seasonal biological and temperature effects". Deep-Sea Res. Pt. II 49 (9–10): 1601–1622. doi:10.1016/S0967-0645(02)00003-6. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VGC-452W7KK-2&_user=10&_coverDate=12%2F31%2F2002&_rdoc=2&_fmt=summary&_orig=browse&_srch=doc-info(%23toc%236035%232002%23999509990%231%23FLA%23display%23Volume)&_cdi=6035&_sort=d&_docanchor=&view=c&_ct=19&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1eb682d5552c8d58911ddf6e2012da02. 
  4. ^ Orr, J. C.; Maier-Reimer, E.; Mikolajewicz, U.; Monfray, P.; Sarmiento, J. L.; Toggweiler, J. R.; Taylor, N. K.; Palmer, J. et al. (2001). "Estimates of anthropogenic carbon uptake from four three-dimensional global ocean models". Global Biogeochem. Cycles 15: 43–60. Bibcode 2001GBioC..15...43O. doi:10.1029/2000GB001273. 
  5. ^ Yool, A.; Fasham, M. J. R. (2001). "An examination of the "continental shelf pump" in an open ocean general circulation model". Global Biogeochem. Cycles 15 (4): 831–844. Bibcode 2001GBioC..15..831Y. doi:10.1029/2000GB001359. 
  6. ^ Frankignoulle, M.; Borges, A. V. (2001). "European continental shelf as a significant sink for atmospheric carbon dioxide". Global Biogeochemical Cycles 15: 569–576. 
  7. ^ DeGrandpre, M. D.; Olbu, G. J.; Beatty, C. M.; Hammar, T. R. (2002). "Air-sea CO2 fluxes on the US Middle Atlantic Bight". Deep-Sea Research Part II 49 (20): 4355–4367. doi:10.1016/S0967-0645(02)00122-4. 
  8. ^ Thomas, H.; Bozec, Y.; Elkalay, K.; Baar, H. J. W. De (2004). "Enhanced open ocean storage of CO2 from shelf sea pumping". Science 304 (5673): 1005–1008. doi:10.1126/science.1095491. PMID 15143279. 
  9. ^ Cai, Wei-Jun (2003). "The role of marsh-dominated heterotrophic continental margins in transport of CO2 between the atmosphere, the land-sea interface and the ocean". Geophysical Research Letters 30 (16). Bibcode 2003GeoRL..30pOCE3C. doi:10.1029/2003GL017633. 
  10. ^ Borges, A. V. (2005). "Do we have enough pieces of the jigsaw to integrate CO2 fluxes in the Coastal Ocean?". Estuaries 28: 3–27. doi:10.1007/BF02732750. 
  11. ^ Borges A. V., B. Delille and M. Frankignoulle (2005). Budgeting sinks and sources of CO2 in the coastal ocean: Diversity of ecosystems counts, Geophysical Research Letters 32, L14601, doi:10.1029/2005GL023053.

Wikimedia Foundation. 2010.

См. также в других словарях:

  • Continental - получить на Академике действующий промокод Евродиски или выгодно continental купить со скидкой на распродаже в Евродиски

  • Continental shelf — Marine habitats Anatomy of a continental shelf off the south eastern coast of the United States Littoral zone Intertidal zone …   Wikipedia

  • Biological pump — In oceanic biogeochemistry, the biological pump is the sum of a suite of biologically mediated processes that transport carbon from the surface euphotic zone to the ocean s interior. OverviewThe organic carbon that forms the biological pump is… …   Wikipedia

  • Solubility pump — In oceanic biogeochemistry, the solubility pump is a physico chemical process that transports carbon (as dissolved inorganic carbon) from the ocean s surface to its interior.OverviewThe solubility pump is driven by the coincidence of two… …   Wikipedia

  • Ocean acidification — Change in sea water acidity pH caused by anthropogenic CO2 between the 1700s and the 1990s Ocean acidification is the name given to the ongoing decrease in the pH and increase in acidity of the Earth …   Wikipedia

  • List of fishing topics — This page is a list of fishing topics. AlphanumericTOC align=center nobreak= numbers= seealso= externallinks= references= top=| 11959 Escuminac Hurricane22004 Morecambe Bay cockling disasterAA Pobra do Caramiñal A River Somewhere Abalone ABU… …   Wikipedia

  • List of fishing topics by subject — This page is a list of fishing topics by subject. Most fishing articles have a side bar at the top right. This page mirrors the topics in the side bars. See also: List of fishing topics and Fisheries glossary   Contents:… …   Wikipedia

  • Global Ocean Data Analysis Project — The Global Ocean Data Analysis Project (GLODAP) is a synthesis project bringing together oceanographic data collected during the 1990s by research cruises on the World Ocean Circulation Experiment (WOCE), Joint Global Ocean Flux Study (JGOFS) and …   Wikipedia

  • Ocean thermal energy conversion — Temperature differences between the surface and 1000m depth in the oceans Ocean Thermal Energy Conversion (OTEC) uses the difference between cooler deep and warmer shallow or surface ocean waters to run a heat engine and produce useful work,… …   Wikipedia

  • Norway — /nawr way/, n. Norwegian, Norge. a kingdom in N Europe, in the W part of the Scandinavian Peninsula. 4,404,456; 124,555 sq. mi. (322,597 sq. km). Cap.: Oslo. * * * Norway Introduction Norway Background: Despite its neutrality, Norway was not able …   Universalium

  • Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry       The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… …   Universalium


Поделиться ссылкой на выделенное

Прямая ссылка:
Нажмите правой клавишей мыши и выберите «Копировать ссылку»