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发表于 2015-10-8 13:13:40
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Jan-Berend W. Stuut
Ever sincemyMaster’s project, during which I tried to recognise and quantify windblown
dust in marine sediments from the Indian Ocean, I have been fascinated
by aeolian dust. Together with and supervised by Maarten Prins, we managed
to characterise and quantify dust in marine sediments from both the Indian- and
south-eastern Atlantic oceans, simply by studying the grain-size distribution of
deep-marine sediments. A powerful proxy indeed! I continued studying mineral
dust for my PhD studies offshore Namibia and established a reconstruction of
environmental changes in south-western Africa. It turned out that climate in this
part of Africa was related to ocean circulation but showed a pattern that was exactly
opposite to the well-established paleoclimate records from the northern hemisphere.
When looking at these records I am literally still amazed how the patterns in the
grain size of the terrigenous sediments and those in the •18O of surface-ocean
unicellular calcifiers line up so nicely although they are totally independent proxies!
After finishing my PhD in 2001, I moved on to the University of Bremen, Germany,
for a postdoc to study mineral dust in marine sediments offshore Chile to see if
climate throughout the late Quaternary followed the same southern-hemisphere
pattern, which it did! I thank both Gerold Wefer and Dierk Hebbeln for their
unrelenting support and for giving me the freedom to go my own way “chasing
dust” during two more postdoc phases in Bremen.
While studying dust in marine sediment archives, I found that it is quite possible
and of vital importance to ground-truth observations inferred from dust deposits
by comparing them with present-day processes of dust mobilisation, dispersal,
and deposition. I am much obliged to Ralph Schneider who invited me to join
his research cruise on board RV Meteor in 1998 to collect Saharan dust from the
atmosphere while sailing from southern Spain to Gabon all along the west African
coast. This was a typical example of being at the right place at the right time because
we happened to sail through a few giant dust outbreaks: an amazing experience and
probably a trigger similar to Peter’s observation of the March 2004 dust storm. For
the first time we managed to combine the set of actual dust samples collected on
board the ship with satellite data and the daily meteorological observations done
by the German Weather Service on board the ship. By studying back-trajectories
of the different air masses we located with the weather-balloon data, we managed
to trace the different dust particles back to their sources. Many ship cruises and
dust sampling campaigns later we still have more questions than answers regarding
dust dispersal and deposition and also the marine environmental effects of dust
deposition: enough work to be done!
One more colleague that played a critical role in my dusty career is Patrick De
Deckker who picked up and stimulated my curiosity after the role of the southern
hemisphere on global climate. Within weeks after we met, he managed to transfer
our ideas into an ARC (the Australian NSF) proposal to study Australian dust
sources. We got funded to go into the Australian outback to fingerprint the many
different dust sources based on geology, mineralogy, chemistry and microbiology.
These field trips were truly amazing and they broadened my horizon in many ways.
Another event that I think has been essential in shaping my dusty career is a
project by the Dutch TV channel VPRO, who organised a trip on board the clipper
Stad Amsterdam in 2010, retracing Charles Darwin’s travels on board HMS Beagle.
They allowed me to participate in this cruise by installing a dust collector on deck
sampling the atmosphere offshore the large deserts they passed, just like Darwin
did. The trip made me aware of how easily scientific results can be misused to make
money. On the ship I discussed a lot with a so-called geo-engineer who wanted to
make money by fertilising the ocean with powdered iron ore in order to combat
global warming. His motivation was based on John Martin’s iron hypothesis which
states that phytoplankton can sequester CO2 from the atmosphere, and that there are
certain iron-limited parts of the ocean in which phytoplankton can benefit from iron
additions. These discussions convinced me of the fact that fundamental research is
of vital importance for applied sciences as well and that great care should be taken
when disturbing natural balances. As a result I am now working on three parallel
projects in which we collect Saharan dust along a transatlantic transect between
NW Africa and the Caribbean using tethered surface buoys and moored submarine
sediment traps to study the marine environmental effects of dust deposition.
When I wanted to present my results in a big meeting like the European
Geosciences Union, I found that actually there were no sessions in which my work
fitted very well. As a result, the EGU program committee (by then still called EGS)
was kind enough to allow Maarten Prins and me to organise our first dust session in
Nice in 2004. It came down to us writing emails to invite people that we only knew
from their dusty papers and ask them to join us in Nice to discuss mineral dust.
The incredible thing was: virtually all these famous people (e.g., Grant McTainsh
a.k.a. “Dr Dust”, Joe Prospero, Ed Derbyshire, Martin Iriondo, Misao Mikami, Ina
Tegen, Slobodan Markovic, Jean Robert Petit, Ludwig Zöller, Patrick De Deckker,
Dennis Rousseau, Ian Smalley, to name a few) responded enthusiastically and
came! From the first one on, our dust session was a great success with many
very interesting contributions from almost all scientific disciplines one can think of
related to mineral dust, which are also presented in this book. Throughout the years
I had the pleasure to have worked together with different co-convenors (Maarten
Prins, Andreas Baas, Peter Knippertz, Sue McLaren) and our sessions have been
a continuous success, supported by many contributors presenting their fascinating
work and ideas. I have enjoyed bringing people together in workshops and sessions
like this and this book is just another result from this exercise of bridging gaps
between scientific disciplines.
I wish to explicitly thank my co-editor Peter Knippertz who also put a lot of
energy in organising the sessions in Vienna and came up with the idea to produce a
state-of-the-art overview of the interdisciplinary studies of mineral dust in the form
of this book.
Last but not least I would like to thank my direct dusty teammates in Bremen and
at NIOZ, Inka Meyer, Conny Saukel, Carmen Friese, Malte Jäger, Felix Temmesfeld,
Michelle van der Does, Laura Korte, Chris Munday, Geert-Jan Brummer,
Esmee Geerken, Yvo Witte, Edwin Keijzer, and Bob Koster as well as generous
funding by NIOZ and MARUM and by the German Science Foundation (DFG)
through the DFG-Research Center/Cluster of Excellence “The Ocean in the Earth
System”, the Dutch Science Foundation (NWO), the Qatari Science Foundation
(QNRF), the Australian Science Foundation (ARC), and the European Research
Council (ERC).
Texel, The Netherlands Jan-BerendW. Stuut
Bremen, Germany
July 2014 |
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