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2. Challenges to the Future Conservation of the Antarctic

Author

Chown, S. L., Lee, J. E., Hughes, K. A., Barnes, J., Barrett, P. J., Bergstrom, D. M., Convey, P., Cowan, D. A., Crosbie, K., Dyer, G., Frenot, Y., Grant, S. M., Herr, D., Kennicutt, M. C., II, Lamers, M., Murray, A., Possingham, H. P., Reid, K., Riddle, M. J., Ryan, P. G., Sanson, L., Shaw, J. D., Sparrow, M. D., Summerhayes, C., Terauds, A., and Wall, D. H.

Published
2012
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3. MAMA—Towards a new paradigm for ocean monitoring in the Mediterranean

Author

Vallerga, S., primary, Drago, A., additional, Aarup, T., additional, Abdelbaki, A., additional, Abuissa, A., additional, Awad, H., additional, Awad, M.B., additional, Beken, C., additional, Besiktepe, S., additional, Boargob, A.F., additional, Brundrit, G., additional, Capari, M., additional, Carlier, A., additional, Cermelj, B., additional, Casazza, G., additional, Civili, F.S., additional, Cohen, Y., additional, Tziavos, C., additional, Dahlin, H., additional, Dalla Costa, M., additional, Drakopoulos, P., additional, Flemming, N.C., additional, Font, J., additional, Fusco, G., additional, Gertman, I., additional, Georgiou, G., additional, Harzallah, A., additional, Herrouin, G., additional, Ibrahim, A., additional, Kabbara, N., additional, Kljajic, Z., additional, Kouyoumjian, H., additional, Legrand, J., additional, Lopez-Jurado, J.L., additional, Magni, P., additional, Mahmoud, A., additional, Maillard, Al-Sheikh C., additional, Malacic, V., additional, Manzella, G.M.R., additional, Marchand, P., additional, Morovic, M., additional, Pissierssens, P., additional, Pinardi, N., additional, Nittis, K., additional, Rosen, D.S., additional, Summerhayes, C., additional, Ribotti, A., additional, Reed, G., additional, Selenica, A., additional, Salihoglu, I., additional, Sammari, C., additional, Sauzade, D., additional, Silvestri, C., additional, Snoussi, M., additional, Sorgente, R., additional, Umgiesser, G., additional, Vargas, M., additional, Vucijak, B., additional, Woods, J., additional, Zavatarelli, M., additional, and Zodiatis, G., additional

Published
2003
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10. Enhanced productivity on the Iberian margin during glacial/interglacial transitions revealed by barium and diatoms

Author

THOMSON, J., NIXON, S., SUMMERHAYES, C. P., ROHLING, E. J., SCHONFELD, J., ZAHN, R., GROOTES, P., ABRANTES, F., GASPAR, L., and VAQUEIRO, S.

Subjects
Geology, Stratigraphic -- Pleistocene, Barium -- Research, Glaciers -- Research, Sedimentation and deposition -- Research, Earth sciences
Abstract

The Portuguese margin is at a critical location for studies of the ocean's behaviour during glacial/interglacial climatic changes, and the rapid accumulation rates of the sediments enable high-resolution palaeoclimatic investigation. The sedimentary record of the past 350 ka has been investigated in a 35 m long core from 3.5 km water depth on the slope at 40 [degrees] N by geochemical, isotopic and micropalaeontological techniques. The Ca[CO.sub.3] content of this core as a function of time contains significant Milankovitch orbital frequencies of 18.8, 23.7, 38.0 and 100.6 ka, but these are driven primarily by dilution by clay-flux variations rather than by Ca[CO.sub.3] productivity variations. The largest signals in the productivity indicators [C.sub.org], Ba/Al and diatom abundance are all observed as simultaneous peaks at the oxygen isotope stage boundaries 10/9 and 6/5, with the signal magnitude in the order 10/9 [is greater than] 6/5 for all three indicators. Smaller coincident signals in [C.sub.org], Ba/Al but not diatoms are also observed at the oxygen isotope stage 2/1 boundary. Other less prominent peaks in the [C.sub.org] and Ba/Al profiles occur elsewhere, including Heinrich Event horizons, but these are not always simultaneous and none contain evidence of the dissolution-prone diatom microfossils. The 10/9, 6/5 and 2/1 oxygen isotope stage transitions represent the three most extreme glacial/interglacial sea level rises in the past 350 ky, possibly in the same sequence of magnitude, when sea level rose rapidly by 120+m from glacial low stands to interglacial high stands. The productivity signals at these transitions are contained within [is less than] 5 ka (including bioturbation). Keywords: Pleistocene, Iberian margin, sedimentation, oxygen isotopes, barium.

Published
2000

13. The Antarctic environment in the global system

Author

Ainsley D, Barrett P, Bindschadler R, Clarke A, Convey P, Fahrbach E, Gutt J, Hodgson D, Meredith M, Murray A, Pörtner H-O, di Prisco G, Schiel S, Speer K, Summerhayes C, Turner J, Verde C, and Willems A.

Published
2009

15. MAMA - Towards a new paradigm for ocean monitoring in the Mediterranean

Author

Vallerga S., A. Drago, Aarup T., Abdelbaki A., Abuissa A., Awad H., Awad M.B., Beken C., Besiktepe S., Boargob A.F., Brundrit G., Capari M., Carlier A., Cermelj B., Casazza G., Civili F.S., Cohen Y., Christos T., Dahlin H., Dalla Costa M., Drakopoulos P., Flemming N.C., Font J., Fusco G., Gertman I., Harzallah A., Herrouin G., Ibrahim A., Kabbara N., Kljajic Z., Kouyoumjian H., Legrand J., Lopez-Jurado J.L., Magni P., Mahmoud Al-Sheikh A., Maillard C., Malacic V., Manzella G.M.R., Marchand P., Morovic M., Pissierssens P., Pinardi N., Nittis K., Rosen D.S., Summerhayes C., Ribotti A., Reed G., Selenica A., Salihoglu I., Sammari C., Sauzade D., Silvestri C., Snoussi M., Sorgente, Tziavos C., Umgiesser G., Vargas M., Vucijak B., Woods J., Zavatarelli M., and Zodiatis G .

Subjects
operational oceanography, capacity building, networking, awareness, Mediterranean
Abstract

Sustainable development requires the intelligent management of the marine environment, to protect the marine ecosystem, minimise the impacts of climate change and anthropogenic influences, and provide benefits for a wide range of users. Routine ocean monitoring and forecasting based on sound science, long term and adaptive monitoring,, and co-operation between nations, is the main tool for such a management. The assets and needs of all countries have to be identified, as well as the constraints impeding data exchange and marine observations in the EEZs. The challenge is to build a monitoring system based on up-to-date science and technology, and adapted to the specificity of the basin for the benefit of different users in all Mediterranean countries. It is necessary to involve all riparian countries in the process of building the Mediterranean monitoring system. A strengthened and dedicated link between the scientific community and the public authorities is moreover necessary to provide a sound scientific background for policy decisions based on environmental monitoring. Building on these concepts the Mediterranean network to Assess and upgrade the Monitoring and forecasting Activity in the region (MAMA), funded under the EESD Programme of the 5th FP, and involving partners from all the Mediterranean countries, aims to establish the multi-national network that will prepare the institutional linkages and regional platform for such an integrated and sustained monitoring system in the region. The project builds on the trans-national pooling of scientific and technological resources and provides a concerted basin-scale effort towards the planning and design of the initial ocean observing system in the Mediterranean. The system-wide approach of MAMA is expected to trigger an enhanced motivation on the relevance of systematic marine observations for the sustainable and shared use of the marine resources of the Mediterranean Sea. These catalytic ingredients constitute the thrust of MAMA and an enabling asset to the future projection into long-term commitments at governmental level.

Published
2003

16. Antarctic climate change and the environment: an update

Author

Turner, J., Barrand, N.E., Bracegirdle, T.J., Convey, P., Hodgson, D.A., Jarvis, M., Jenkins, A., Marshall, G., Meredith, M.P., Roscoe, H., Shanklin, J., French, J., Goosse, H., Guglielmi, M., Gutt, Julian, Jacobs, S., Kennicutt II, M.C., Masson-Delmotte, V., Mayewski, P., Navarro, F., Robinson, S., Scambos, T., Sparrow, M., Summerhayes, C., Speer, K., Klepikov, A., Turner, J., Barrand, N.E., Bracegirdle, T.J., Convey, P., Hodgson, D.A., Jarvis, M., Jenkins, A., Marshall, G., Meredith, M.P., Roscoe, H., Shanklin, J., French, J., Goosse, H., Guglielmi, M., Gutt, Julian, Jacobs, S., Kennicutt II, M.C., Masson-Delmotte, V., Mayewski, P., Navarro, F., Robinson, S., Scambos, T., Sparrow, M., Summerhayes, C., Speer, K., and Klepikov, A.

Published
2013

17. The Antarctic climate change and the environment (ACCE) report: A key update

Author

Turner, J., Barrant, N.E., Bracegirdle, T.J., Convey, P., Hodgson, D.A., Jarvis, M., Jenkins, A., Marshall, G., Meredith, M.P., Roscoe, H., Shanklin, J., French, J., Goosse, H., Guglielmin, M., Gutt, Julian, Jacobs, S., Kennicut II, M.C., Masson-Delmotte, V., Mayewski, P., Navarro, Francisco, Robinson, S., Scambos, T., Sparrow, M., Summerhayes, C., Speer, K., Klepikov, A., Turner, J., Barrant, N.E., Bracegirdle, T.J., Convey, P., Hodgson, D.A., Jarvis, M., Jenkins, A., Marshall, G., Meredith, M.P., Roscoe, H., Shanklin, J., French, J., Goosse, H., Guglielmin, M., Gutt, Julian, Jacobs, S., Kennicut II, M.C., Masson-Delmotte, V., Mayewski, P., Navarro, Francisco, Robinson, S., Scambos, T., Sparrow, M., Summerhayes, C., Speer, K., and Klepikov, A.

Published
2013

19. The Southern Ocean observing system: Initial science and implementation strategy

Author

Rintoul, S. R., Sparrow, M., Meredith, M. P., Wadley, V., Speer, K., Hofmann, E., Summerhayes, C., Urban, E., Bellerby, R., Ackley, S., Alverson, K., Ansorge, I., Aoki, S., Azzolini, R., Beal, L., Belbeoch, M., Bergamasco, A., Biuw, M., Boehme, L., Budillon, G., Campos, L., Carlson, D., Cavanagh, R., Charpentier, E., Chul Shin, H., Coffin, M., Constable, A., Costa, D., Cronin, M., De Baar, H., De Broyer, C., De Bruin, T., De Santis, L., Butler, E., Dexter, P., Drinkwater, M., England, M., Fahrbach, Eberhard, Fanta, E., Fedak, M., Finney, K., Fischer, A., Frew, R., Garzoli, S., Gernandt, Hartwig, Gladyshev, S., Gomis, D., Gordon, A., Gunn, J., Gutt, Julian, Haas, C., Hall, J., Heywood, K., Hill, K., Hindell, M., Hood, M., Hoppema, Mario, Hosie, G., Howard, W., Joiris, C., Kaleschke, L., Kang, S.-H., Kennicutt, M., Klepikov, A., Lembke-Jene, Lester, Lovenduski, N., Lytle, V., Mathieu, P.-P., Moltmann, T., Morrow, R., Muelbert, M., Murphy, E., Naganobu, M., Naveira Garabato, A., Nicol, S., O'Farrell, S., Ott, N., Piola, A., Piotrowicz, S., Proctor, R., Qiao, F., Rack, F., Ravindra, R., Ridgway, K., Rignot, E., Ryabinin, V., Sarukhanian, E., Sathyendranath, S., Schlosser, P., Schwarz, J., Smith, G., Smith, S., Southwell, C., Speich, S., Stambach, W., Stammer, D., Stansfield, K., Thiede, Jörn, Thouvenot, E., Tilbrook, B., Wadhams, P., Wainer, I., Willmott Puig, Veronica, Wijffels, S., Woodworth, P., Worby, T., Wright, S., Rintoul, S. R., Sparrow, M., Meredith, M. P., Wadley, V., Speer, K., Hofmann, E., Summerhayes, C., Urban, E., Bellerby, R., Ackley, S., Alverson, K., Ansorge, I., Aoki, S., Azzolini, R., Beal, L., Belbeoch, M., Bergamasco, A., Biuw, M., Boehme, L., Budillon, G., Campos, L., Carlson, D., Cavanagh, R., Charpentier, E., Chul Shin, H., Coffin, M., Constable, A., Costa, D., Cronin, M., De Baar, H., De Broyer, C., De Bruin, T., De Santis, L., Butler, E., Dexter, P., Drinkwater, M., England, M., Fahrbach, Eberhard, Fanta, E., Fedak, M., Finney, K., Fischer, A., Frew, R., Garzoli, S., Gernandt, Hartwig, Gladyshev, S., Gomis, D., Gordon, A., Gunn, J., Gutt, Julian, Haas, C., Hall, J., Heywood, K., Hill, K., Hindell, M., Hood, M., Hoppema, Mario, Hosie, G., Howard, W., Joiris, C., Kaleschke, L., Kang, S.-H., Kennicutt, M., Klepikov, A., Lembke-Jene, Lester, Lovenduski, N., Lytle, V., Mathieu, P.-P., Moltmann, T., Morrow, R., Muelbert, M., Murphy, E., Naganobu, M., Naveira Garabato, A., Nicol, S., O'Farrell, S., Ott, N., Piola, A., Piotrowicz, S., Proctor, R., Qiao, F., Rack, F., Ravindra, R., Ridgway, K., Rignot, E., Ryabinin, V., Sarukhanian, E., Sathyendranath, S., Schlosser, P., Schwarz, J., Smith, G., Smith, S., Southwell, C., Speich, S., Stambach, W., Stammer, D., Stansfield, K., Thiede, Jörn, Thouvenot, E., Tilbrook, B., Wadhams, P., Wainer, I., Willmott Puig, Veronica, Wijffels, S., Woodworth, P., Worby, T., and Wright, S.

Published
2012

20. 5.1 Early Science Outcomes of IPY 20072008

Author

Bell, R., Allison, I., Alverson, K., Danell, K., Fahrbach, Eberhard, Krupnik, I., López- Martínez, J., Sarukhanian, E., Summerhayes, C., Bell, R., Allison, I., Alverson, K., Danell, K., Fahrbach, Eberhard, Krupnik, I., López- Martínez, J., Sarukhanian, E., and Summerhayes, C.

Published
2011

21. 2.3. Southern Ocean

Author

Rintoul, S. R., Fahrbach, Eberhard, Abele, Doris, Ackley, S., Allison, I., Bowie, A., Brandt, A., Brussaard, C., Cavanagh, R. D., Danis, B., De Baar, H., De Broyer, C., Evans, C., Heywood, K., Hofmann, E., Hoppema, Mario, Iversen, S. A., Johnston, N. M., Klepikov, A., Luis, A. J., Murphy, E. J., Segers, H., Strass, Volker, Summerhayes, C., Tancell, C., Wadley, V., Woodworth, P., Worby, A., Rintoul, S. R., Fahrbach, Eberhard, Abele, Doris, Ackley, S., Allison, I., Bowie, A., Brandt, A., Brussaard, C., Cavanagh, R. D., Danis, B., De Baar, H., De Broyer, C., Evans, C., Heywood, K., Hofmann, E., Hoppema, Mario, Iversen, S. A., Johnston, N. M., Klepikov, A., Luis, A. J., Murphy, E. J., Segers, H., Strass, Volker, Summerhayes, C., Tancell, C., Wadley, V., Woodworth, P., and Worby, A.

Published
2011

22. Antarctic Climate Change and the Environment - 2011 Update.

Author

Turner, J., Summerhayes, C., Sparrow, M., Mayewski, P., Convey, P., di Prisco, G., Gutt, Julian, Hodgson, D., Speich, S., Worby, T., Bo, S., Klepikov, A., Turner, J., Summerhayes, C., Sparrow, M., Mayewski, P., Convey, P., di Prisco, G., Gutt, Julian, Hodgson, D., Speich, S., Worby, T., Bo, S., and Klepikov, A.

Published
2011

23. Antarctic Climate Change and the Environment - An Update.

Author

Turner, J., Bindschadler, R., Convey, P., di Prisco, G., Fahrbach, Eberhard, Gutt, Julian, Hodgson, D., Mayewski, P., Summerhayes, C., Turner, J., Bindschadler, R., Convey, P., di Prisco, G., Fahrbach, Eberhard, Gutt, Julian, Hodgson, D., Mayewski, P., and Summerhayes, C.

Published
2010

24. Southern Ocean Observing System (SOOS): Rationale and strategy for sustained observations of the Southern Ocean

Author

Hall, J., Harrison, D.E., Stammer, D., Rintoul, S.R., Speer, K., Sparrow, M., Meredith, Michael, Hofmann, E., Fahrbach, E., Summerhayes, C., Worby, A., England, M., Bellerby, R., Speich, S., Costa, D., Hindell, M., Hosie, G., Stansfield, K., Fukamachi, Y., de Bruin, T., Naveira Garabato, A., Alverson, K., Ryabinin, V., Shin, H.C., Gladyshev, S., Hall, J., Harrison, D.E., Stammer, D., Rintoul, S.R., Speer, K., Sparrow, M., Meredith, Michael, Hofmann, E., Fahrbach, E., Summerhayes, C., Worby, A., England, M., Bellerby, R., Speich, S., Costa, D., Hindell, M., Hosie, G., Stansfield, K., Fukamachi, Y., de Bruin, T., Naveira Garabato, A., Alverson, K., Ryabinin, V., Shin, H.C., and Gladyshev, S.

Abstract

By connecting the ocean basins and the upper and lower limbs of the ocean overturning circulation, the Southern Ocean plays a critical role in the global ocean circulation, biogeochemical cycles and climate. Limited observations suggest the Southern Ocean is changing: the region is warming more rapidly than the global ocean average; salinity changes driven by changes in precipitation and ice melt have been observed in both the upper and abyssal ocean; the uptake of carbon by the Southern Ocean has slowed the rate of climate change but increased the acidity of the Southern Ocean; and there are indications of ecosystem changes. However, the short and incomplete nature of existing time series means that the causes and consequences of observed changes are difficult to assess. Sustained, multidisciplinary observations are required to detect, interpret and respond to change. The Southern Ocean Observing System (SOOS) will provide the long-term measurements required to improve understanding of climate change and variability, biogeochemical cycles and the coupling between climate and marine ecosystems.

Published
2010

25. Antarctic climate change and the environment

Author

Convey, P., Bindschadler, R., Di Prisco, G., Fahrbach, E., Gutt, J., Hodgson, D. A., Mayewski, P. A., Summerhayes, C. P., Turner, J., ACCE CONSORTIUM, Convey, P., Bindschadler, R., Di Prisco, G., Fahrbach, E., Gutt, J., Hodgson, D. A., Mayewski, P. A., Summerhayes, C. P., Turner, J., and ACCE CONSORTIUM

Abstract

The Antarctic climate system varies on timescales from orbital, through millennial to sub-annual, and is closely coupled to other parts of the global climate system. We review these variations from the perspective of the geological and glaciological records and the recent historical period from which we have instrumental data (similar to the last 50 years). We consider their consequences for the biosphere, and show how the latest numerical models project changes into the future, taking into account human actions in the form of the release of greenhouse gases and chlorofluorocarbons into the atmosphere. In doing so, we provide an essential Southern Hemisphere companion to the Arctic Climate Impact Assessment.

Published
2009
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26. Antarctic climate change and the environment

Author

Convey, P C, Bindschadler, R, Di Prisco, G, Fahrbach, E, Gutt, J, Hodgson, D A, Mayewski, P, Summerhayes, C P, Turner, J, Robinson, Sharon A., Convey, P C, Bindschadler, R, Di Prisco, G, Fahrbach, E, Gutt, J, Hodgson, D A, Mayewski, P, Summerhayes, C P, Turner, J, and Robinson, Sharon A.

Abstract

The Antarctic climate system varies on timescales from orbital, through millennial to sub-annual, and is closely coupled to other parts of the global climate system. We review these variations from the perspective of the geological and glaciological records and the recent historical period from which we have instrumental data (the last 50 years). We consider their consequences for the biosphere, and show how the latest numerical models project changes into the future, taking into account human actions in the form of the release of greenhouse gases and chlorofluorocarbons into the atmosphere. In doing so, we provide an essential Southern Hemisphere companion to the Arctic Climate Impact Assessment.

Published
2009

27. The Southern Ocean Observing System (SOOS)

Author

Fahrbach, Eberhard, Rintoul, S., Sparrow, M., Hofmann, E., Summerhayes, C., Fahrbach, Eberhard, Rintoul, S., Sparrow, M., Hofmann, E., and Summerhayes, C.

Abstract

The importance of the Southern Ocean to the global climate system and the uniqueness of its ecosystems are well known. The region is remote and logistically difficult to access and thus is one of the least sampled regions on the planet. Design and implementation of an observing system that encompasses physical, biogeochemical and ecological processes is therefore a formidable challenge. Building on meetings held in Hobart in 2006, Bremen in 2007 and St Petersburg in 2008 we present a draft plan for a Southern Ocean Observing System (SOOS). This document examines: (i) why sustained observations are needed in the Southern Ocean and what science/policy questions they address; (ii) what mix of observations are required to address these questions; (iii) what is presently done and possible and (iv) a vision for the future. SOOS is a key component of the SCAR Pan Antarctic Observing System (PantOS) and is co-sponsored by the Scientific Committee on Antarctic Research (SCAR), the Scientific Committee on Oceanic Research (SCOR), the Census of Antarctic Marine Life (CAML), the Partnership for Observation of the Global Oceans (POGO) and the Global Ocean Observing System (GOOS). Other organisations, in particular the National Oceanic and Atmospheric Administration (NOAA), have provided significant funding.

Published
2008

28. Risks posed to the Antarctic marine environment by acoustic instruments: a structured analysis

Author

Boebel, Olaf, Clarkson, P., Coates, R., Larter, R., O'Brien, P., Plötz, Joachim, Summerhayes, C., Tyack, T., Walton, D., Wartzok, D., Boebel, Olaf, Clarkson, P., Coates, R., Larter, R., O'Brien, P., Plötz, Joachim, Summerhayes, C., Tyack, T., Walton, D., and Wartzok, D.

Abstract

The risks posed by a range of acoustic scientific instruments were assessed by the construction of matrices of scale and likelihood. We recognized six levels of impact ranging from none or short term, minimal behavioural response (Level 1) to multiple injuries and fatalities and/or compromised populations (Level 6) and six levels of likelihood ranging from Expected in almost all instances (Level 1) to cannot see how it could happen (Level 6). Typical scientific instruments ranging from acoustic releases to large air gun arrays were assessed. To provide a perspective for the risks of scientific operations, other activities were also ranked. These included large chemical explosions, submarine detection sonars implicated in some mass strandings of cetaceans and normal Antarctic shipping activities. The conclusion reached was that most scientific instruments pose a similar or lower risk than normal shipping operations. High source-level equipment poses some risk to individual animals' hearing and so should be mitigated. Likewise, survey planning should be designed to avoid trapping animals in narrow, constricted sea ways. Long term, cumulative impacts are still difficult to detect in areas with greater anthropogenic noise than the Antarctic but we concluded that any possible long term impacts should be mitigated by maintaining the low levels of activity using high source-level equipment through data sharing and survey planning.

Published
2005

29. Risks posed to the Antarctic marine environment by acoustic instruments: a structured analysis

Author

Boebel, O., Clarkson, P., Coates, R., Larter, R., O'Brien, P.E., Ploetz, J., Summerhayes, C., Tyack, T., Walton, D.W.H., Wartzok, D., Boebel, O., Clarkson, P., Coates, R., Larter, R., O'Brien, P.E., Ploetz, J., Summerhayes, C., Tyack, T., Walton, D.W.H., and Wartzok, D.

Abstract

The risks posed by a range of acoustic scientific instruments were assessed by the construction of matrices of scale and likelihood. We recognized six levels of impact ranging from none or short term, minimal behavioural response (Level 1) to multiple injuries and fatalities and/or compromised populations (Level 6) and six levels of likelihood ranging from “Expected in almost all instances” (Level 1) to “cannot see how it could happen” (Level 6). Typical scientific instruments ranging from acoustic releases to large air gun arrays were assessed. To provide a perspective for the risks of scientific operations, other activities were also ranked. These included large chemical explosions, submarine detection sonars implicated in some mass strandings of cetaceans and normal Antarctic shipping activities. The conclusion reached was that most scientific instruments pose a similar or lower risk than normal shipping operations. High source-level equipment poses some risk to individual animals' hearing and so should be mitigated. Likewise, survey planning should be designed to avoid trapping animals in narrow, constricted sea ways. Long term, cumulative impacts are still difficult to detect in areas with greater anthropogenic noise than the Antarctic but we concluded that any possible long term impacts should be mitigated by maintaining the low levels of activity using high source-level equipment through data sharing and survey planning.

Published
2005

31. State of the Antarctic and Southern Ocean climate system

Author

Mayewski, P. A., primary, Meredith, M. P., additional, Summerhayes, C. P., additional, Turner, J., additional, Worby, A., additional, Barrett, P. J., additional, Casassa, G., additional, Bertler, N. A. N., additional, Bracegirdle, T., additional, Naveira Garabato, A. C., additional, Bromwich, D., additional, Campbell, H., additional, Hamilton, G. S., additional, Lyons, W. B., additional, Maasch, K. A., additional, Aoki, S., additional, Xiao, C., additional, and van Ommen, Tas, additional

Published
2009
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43. Temporal variation in intensity of upwelling off southwest Africa

Author

Summerhayes, C. P., Hay, William W., Brock, J. C., Summerhayes, C. P., Hay, William W., and Brock, J. C.

Abstract

Sediments recovered at DSDP Sites 362 and 532 on Walvis Ridge Abutment Plateau and 530 in the southeastern Angola Basin record long-term waxing and waning of upwelling. The amounts of opaline silica and organic carbon in the sediments increase from latest Miocene to latest Pliocene then decline to present. During the late Pliocene, opaline silica accumulated ten times faster than during the late Pleistocene. If the area of accumulation also expanded to include the Abutment Plateau, this region would have been the global silica sink, consuming the equivalent of the entire silica output of the present ocean. The sediments contain light-dark cycles; the dark cycles contain more terrigenous material and on this basis have been interpreted as representing glacials. Before the Pliocene the maximum biological productivity in this region occurred during the glacials, but since then it has occurred during the interglacials, an effect of sea-level change on productivity opposite to that in most parts of the world. The most important factors causing the changes in sedimentation are judged to be threefold. (1) Closing of the Central American Isthmus resulted in salinization of the North Atlantic and caused increased production of NADW, AAIW and AABW. The increased rate of production of these water masses resulted in differentiation of nutrients among them and may have resulted in a shallower pycnocline facilitating upwelling of nutrient-rich water. The production of relatively nutrient-rich AAIW was a prerequisite for the long term increase in productive upwelling recorded by the late Miocene to latest Pliocene sediments. (2) During the Late Miocene northward migration of the subtropical high and ITCZ in response to growth of the Antarctic ice cap may have initiated productive upwelling over the Abutment Plateau. Subsequent southward migration of the ITCZ as the Earth changed from unipolar to bipolar glaciation would have enhanced the Angola Coastal Current and upwelling from t

Published
1992

44. Transfer functions to reconstruct ocean palaeoproductivity: a comparison

Author

Summerhayes, C. P., Sarntheim, Michael, Pflaumann, U., Ross, R., Tiedemann, Ralf, Winn, Kyaw, Summerhayes, C. P., Sarntheim, Michael, Pflaumann, U., Ross, R., Tiedemann, Ralf, and Winn, Kyaw

Abstract

Oceanic plankton (export) productivity contributes to the control of glacial-to-interglacial changes in atmospheric CO2 concentration. The extent of this contribution may be deciphered from global reconstructions of palaeoproductivity. We quantitatively estimate palaeoproductivity over the last 350 000 years in the eastern equatorial Atlantic, using equations based on foraminiferal assemblages and marine organic carbon accumulation rates; and make qualitative estimates using diatom and radiolarian accumulation rates. These proxydata are calibrated to data on modern primary production.

Published
1992

47. En echelon axial volcanic ridges at the Reykjanes Ridge: a life cycle of volcanism and tectonics

Author

Parson, L.M., primary, Murton, B.J., additional, Searle, R.C., additional, Booth, D., additional, Evans, J., additional, Field, P., additional, Keeton, J., additional, Laughton, A., additional, McAllister, E., additional, Millard, N., additional, Redbourne, L., additional, Rouse, I., additional, Shor, A., additional, Smith, D., additional, Spencer, S., additional, Summerhayes, C., additional, and Walker, C., additional

Published
1993
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