Tuesday, 22 January 2013

Sea level project re-aligned

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!

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