June 2024 | Oceanography
ocean. Hayes provides an overview of
the unique value of the thorium radio-
nuclides as timekeepers for rates in the
ocean and how they aid understand-
ing of manifold biogeochemical pro-
cesses, while Casciotti et al. describe
recent advances in our understanding
of the marine nitrogen cycle that have
come from GEOTRACES and other
efforts. Rafter then looks at how linking
together elements such as iron and nitro-
gen can enhance insights into oceanic
nutrient cycling.
The proliferation of GEOTRACES
datasets has sparked renewed appre-
ciation for the role of physical circula-
tion in influencing global TEI distri-
butions. The paper by de Souza and
Morrison takes a close look at our
increasing understanding of the role of
the Southern Ocean “hub” in driving
global nutrient and TEI distributions.
However, it is not just knowledge of oce-
anic “dissolved” TEIs and circulation that
are needed to understand marine bio-
geochemical cycles; GEOTRACES has
also provided numerous advances in
our knowledge of elemental speciation
and organic complexation, marine par-
ticles, and aerosols as featured by sev-
eral articles in this issue (Whitby et al.,
Twining, and Buck et al., respectively).
Tagliabue and Weber provide an over-
view of how a range of different ocean
biogeochemical modeling approaches
have been stimulated by—and become
invaluable in the interpretation of—
GEOTRACES datasets. Lastly, we look to
the future with Saito et al. describing the
nascent BioGeoSCAPES program, which
aims to build on advances from pro-
grams such as GEOTRACES and stim-
ulate a research program designed to
enhance understanding of the linkages
between microbes, climate change, and
biogeochemical cycles. We eagerly antic-
ipate the development of this new pro-
gram and the continuing discoveries to
come from GEOTRACES.
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ACKNOWLEDGMENTS
We thank Robert Anderson, the US GEOTRACES
Program Office, and the US National Science
Foundation for supporting this Special Issue through
NSF award OCE-2219888. We also thank each of
the authors of the original GEOTRACES Science Plan
(GEOTRACES Planning Group, 2006), whose vision
brought us to the outstanding discoveries described
in this special issue. The international GEOTRACES
program is possible in part thanks to the support from
the US National Science Foundation (Grant OCE-
2140395) to the Scientific Committee on Oceanic
Research (SCOR).
AUTHORS
Tim M. Conway (tmconway@usf.edu) is Associate
Professor, College of Marine Sciences, University
of South Florida, St. Petersburg, FL, USA.
Jessica N. Fitzsimmons is Associate Professor,
Department of Oceanography, Texas A&M University,
College Station, TX, USA. Rob Middag is Research
Leader, Royal Netherlands Institute for Sea Research
(NIOZ), Den Burg, the Netherlands, and Honorary
Professor, Centre for Isotope Research - Oceans,
University of Groningen, Groningen, the Netherlands.
Taryn L. Noble is Senior Lecturer, Institute for Marine
and Antarctic Studies, University of Tasmania,
Hobart, Tasmania, Australia. Hélène Planquette is
Senior Researcher, CNRS, Université de Bretagne
Occidentale, IRD, Ifremer, LEMAR, Plouzané, France.
ARTICLE CITATION
Conway, T.M., J.N. Fitzsimmons, R. Middag,
T.L. Noble, and H. Planquette. 2024. Introduction to
the special issue on twenty years of GEOTRACES:
An international study of the marine biogeo-
chemical cycles of trace elements and isotopes.
Oceanography 37(2):6–7, https://doi.org/10.5670/
oceanog.2024.415.
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