13 July - Sunday

We spent most of the day circuiting around the "flat control" station where we did our point counts yesterday. This allowed us to use line transect methods and cover a lot more ground. The hypothesis being tested is that at a flat site, there should be less feeding activity at the bank by seabirds and that there is no tidal cycle to whatever feeding there is.

Unfortunately, the gannets don't appear to have read the text book. We saw several time the amount of feeding, although there appeared also to be a fairly random spread across locations and tidal cycle.

The rare bird of the day was a puffin. How cute. The rare mammal of the day was a grey seal.

Today's focus on other peoples' work is the biochemists from SAMS (Scottish Association of Marine Science) at Dunstaffnage, near Oban.

Stevie, Morton and Jason preparing the mega-corer

At each station, they are taking a number of samples from the sea bed and the water. The device above (called a mega-corer) takes samples of mud and sand for the sea bed (core samples). These are being analysed to look at levels of heavy metals from what should be a pristine area well away from most sources of pollutants. Sadly, this is not the case from other similar areas, and it is a good way to monitor the levels of pollution of, for example, mercury.

Another device, called a CTD, which stands for conductivity temperature depth. That's it in the photo above. At a basic level it does what it says on the tin; it measures conductivity (which is also a measure of sea salinity) and temperature at different depths below the ship. This allows us to see something called a thermocline, which is stable layers of warm, lower salinity water that is less dense and and floats above colder, higher salinity water. But the CTD is doing much more than this (you can measure temperature and salinity with tiny bits of kit). The plastic tubes collect samples of water at different depths too to test for nutrients, bacteria, phytoplankton (microscopic plants).

Debbie, Keith and Sharon praying to the CTD god

The biochemists from SAMS are taking these different water samples and carrying out all kinds of experiments on the water. They are even trying to isolate bacteria that could be used for breaking down oil pollution, and also the alga that causes harmful red tides (paralytic shellfish poisoning.

OK, just taking off
water samples

Debbie and Romaine ready
to fight the water samples

The denser water below the thermocline tends to be mixed, and full of nutrients circulating and mixing from the sea bed. However, the thermocline forms a barrier that inhibits the flow of nutrients to the levels nearer the surface. These can become depleted of nutrients and therefore all the beasties that need these to prosper near the surface. Here, the thermocline is sitting at about 50 metres below the sea surface - well out of reach of the gannets we are seeing feeding in the area.

So it becomes interesting to see what happens when something like the Jones Bank agitates the water at the thermocline and potentially injects nutrients into upper layers of the thermocline, even as far as the surface. The folks from SAMS are testing to see if nutrients are indeed being brought into the surface layers and if there is enhanced phytoplankton growth in these areas.