Preface
Paleoceanographic proxies provide infonnation for reconstructions of the past, including climate changes,
global and regional oceanography, and the cycles of biochemical components in the ocean. These proxies are measurable descriptors for desired but unobservable environmental variables such as temperature, salinity, primary productivity, nutrient content, or surface-water carbon dioxide concentrations. The
proxies are employed in a manner analogous to oceanographic methods. The water masses are first
characterized according to their specific physical and chemical properties, and then related to particular
assemblages of certain organisms or to particular element or isotope distributions. We have a long-standing
series of proven proxies available. Marine microfossil assemblages, for instance, are employed to
reconstruct surface-water temperatures. The calcareous shells of planktonic and benthic microorganisms contain a wealth of paleoceanographic information in their isotopic and elemental compositions.
Stable oxygen isotope measurements are used to detennine ice volume, and MglCa ratios are related to
water temperatures, to cite a few examples. Organic material may also provide valuable infonnation,
e.g., about past productivity conditions. Studying the stable carbon isotope composition of bulk organic
matter or individual marine organic components may provide a measure of past surface-water CO 2
conditions within the bounds of certain assumptions.
Within the scope of paleoceanographic investigations, the existing proxies are continuously evolving
and improving, while new proxies are being studied and developed. The methodology is improved by
analysis of samples from the water column and surface sediments, and through laboratory experiments.
The use of proxies and their development has been a major theme ofthe Collaborative Research Project
(Sonderforschungsbereich 261, SFB 261) at Bremen University for about 10 years. The main objective
of this research program is to reconstruct current and productivity systems in the South Atlantic for the
last 300,000 years, as well as the northward transport of heat, which has been a major factor in climate
variability during the Pleistocene and Holocene.
Along with the sampling of surface-water particulate matter, the scientists of the SFB 261 have carried
out extensive sediment-trap experiments in the Atlantic and Southern Oceans. In addition, large
surface sediment and sediment core databases retrieved in recent decades during METEOR and
POLARSTERN expeditions are available. In these efforts, the METEOR cruises have concentrated
on wanner regions, while the POLARSTERN of the Alfred Wegener Institute for Polar and Marine
Research (A WI) has routinely recovered samples from Antarctic waters. Participation in Ocean
Drilling Program (ODP) cruises and projects has provided additional stimulation, especially in tenns of
exchange of ideas and experiences with other scientists in the Bremen ODP core repository for cores
from the Atlantic Ocean.
In this volume we summarize results related to proxy studies perfonned in the Atlantic and the Southern
Ocean within the scope of the SFB 261. From the wealth of proxies presently available, some of the
important ones that we apply in the South Atlantic will be elucidated here, for instance: temperature,
salinity, productivity, nutrient content, and surface-water CO 2 concentrations. Proxies relating to atmospheric circulation are also discussed. In addition, the application of magnetic parameters for paleoenvironmental studies is described. Articles about climate modelling and data management (PANGAEA
databank) complete this volume.
Paleoceanographic proxies provide infonnation for reconstructions of the past, including climate changes,
global and regional oceanography, and the cycles of biochemical components in the ocean. These proxies are measurable descriptors for desired but unobservable environmental variables such as temperature, salinity, primary productivity, nutrient content, or surface-water carbon dioxide concentrations. The
proxies are employed in a manner analogous to oceanographic methods. The water masses are first
characterized according to their specific physical and chemical properties, and then related to particular
assemblages of certain organisms or to particular element or isotope distributions. We have a long-standing
series of proven proxies available. Marine microfossil assemblages, for instance, are employed to
reconstruct surface-water temperatures. The calcareous shells of planktonic and benthic microorganisms contain a wealth of paleoceanographic information in their isotopic and elemental compositions.
Stable oxygen isotope measurements are used to detennine ice volume, and MglCa ratios are related to
water temperatures, to cite a few examples. Organic material may also provide valuable infonnation,
e.g., about past productivity conditions. Studying the stable carbon isotope composition of bulk organic
matter or individual marine organic components may provide a measure of past surface-water CO 2
conditions within the bounds of certain assumptions.
Within the scope of paleoceanographic investigations, the existing proxies are continuously evolving
and improving, while new proxies are being studied and developed. The methodology is improved by
analysis of samples from the water column and surface sediments, and through laboratory experiments.
The use of proxies and their development has been a major theme ofthe Collaborative Research Project
(Sonderforschungsbereich 261, SFB 261) at Bremen University for about 10 years. The main objective
of this research program is to reconstruct current and productivity systems in the South Atlantic for the
last 300,000 years, as well as the northward transport of heat, which has been a major factor in climate
variability during the Pleistocene and Holocene.
Along with the sampling of surface-water particulate matter, the scientists of the SFB 261 have carried
out extensive sediment-trap experiments in the Atlantic and Southern Oceans. In addition, large
surface sediment and sediment core databases retrieved in recent decades during METEOR and
POLARSTERN expeditions are available. In these efforts, the METEOR cruises have concentrated
on wanner regions, while the POLARSTERN of the Alfred Wegener Institute for Polar and Marine
Research (A WI) has routinely recovered samples from Antarctic waters. Participation in Ocean
Drilling Program (ODP) cruises and projects has provided additional stimulation, especially in tenns of
exchange of ideas and experiences with other scientists in the Bremen ODP core repository for cores
from the Atlantic Ocean.
In this volume we summarize results related to proxy studies perfonned in the Atlantic and the Southern
Ocean within the scope of the SFB 261. From the wealth of proxies presently available, some of the
important ones that we apply in the South Atlantic will be elucidated here, for instance: temperature,
salinity, productivity, nutrient content, and surface-water CO 2 concentrations. Proxies relating to atmospheric circulation are also discussed. In addition, the application of magnetic parameters for paleoenvironmental studies is described. Articles about climate modelling and data management (PANGAEA
databank) complete this volume.