We’re midway. Are we on schedule? For 1.5 years,
researchers all over the UK have been trying to get a grip on interglacial sea
level changes, within the iGlass project (official link). We’d like to know if sea level during periods of low polar ice
cover fluctuates in general, and if so, how much then. Sea level is currently
rising; how much faster can we expect it to go? Geological data suggests the
fastest rates of sea level occur when there is loads of ice; quite as one would
expect. But just the fact we don’t expect rates of several metres per century
doesn’t mean we can sit back and relax. So we do not. And the time had come to
see how far we had come.
All researchers involved in the project from the
various institutes gathered in Southampton, where our coordinator was based.
And in a meeting room with a view on the very sea, we brought each other up to
date. There is one team trying to constrain interglacial sea level changes
using stable isotopes in foraminifera from the Red Sea (how they manage that is
a complicated story – that merits a blog post in itself). A team in Oxford was
trying to use dripstone formations for this purpose (same there!). We had been
coring around in Norfolk and Cambridgeshire, looking for marine microfossils in
sediments, to do our bit. And all that adventure was complemented by the sturdy
attempts of several teams of data gatherers and modellers: the former would
compile all information already available in literature so as to not have to do
double work. And the latter would try to understand the distribution of land
ice at the time intervals for which we had sea level data. They would also try
to get a grip on the depression and subsequent bouncing back up of the Earth’s
crust due to fluctuations in that ice; you can use that to detect where large
masses of ice have appeared and disappeared (related to the process described here), and thus point to a specific ice
mass as a culprit if you find a big sea level change in your data.
The view from our meeting room
So what, other than just being kept in the loop, is
the use of getting together? Well, science isn’t a linear process. A project
never works out exactly as it was set out in the beginning. And one needs to
adapt to such changes.
We were faced with several changes relating to the
people involved: five of us would move to a different institute than we started
out in at the beginning of the project. Two go abroad; out of reach of our UKfunding agency, so we needed replacements. One of us would even leave science
altogether.
More detailed issues that needed to be discussed
were for instance which interglacial periods (there are many; for practical
reasons, we limit ourselves to the last five) we will focus on, and which time
intervals within these periods. The previous interglacial (~125.000 years ago)
is a favourable one, for the simple reason it is the most recent, so it’s best
documented in the sedimentary archive. Three interglacials back (~400.000 years
ago) is a special one too; the Sun and the Earth were configured in practically
the same way as they are now (quite unlike in the previous interglacial), and
it was a very long one; we decided prioritise these two. And the time slices
the modellers will target are the ones for which the data gatherers have found
the most information.
The home base of the project: the National Oceanography Centre in Southampton
Another issue to be discussed was that we, the
micropalaeontological team, had only budgeted for fieldwork in the UK, but we
had found out about much more promising sediments in the USA. Should we shift
some money around so we could chase these up? It was decided we would. An
exciting prospect opened up!
Two days of presentations, discussions, and a nice
dinner at the end of the first day later, we all dispersed again. We were all
singing from the same hymn sheet again, and the music on it has been brought up
to date with where our data has taken us!
