Swathing and Signy

We have spent the last day or so swathing. This involves bouncing an acoustic signal off the seafloor, which will give a 3d image of the topography. We are sailing in a zigzag pattern at right angles to the part of the seafloor we want to survey. We have to overlap each band of swath and make sure we don’t leave any gaps. This may sound simple but when there are sizeable icebergs directly in the path it can be difficult for the bridge officers to steer a straight course. You can see how it works from the picture below.

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Image: British Antarctic Survey.

We dropped the three scientists who are working on Signy Island and spent the morning ashore. Some of the team walked over a promontory to Cemetery flats where there are a number of whalers’ graves and lots of elephant seals. Elephant seals are noisy and smelly but generally don’t move too quickly. Unlike fure seals which are noisy, smelly and can waddle surprisingly fast!

Ellies angelika

Young male Elephant seals: Image – Angelika Brand.

A few volunteers and myself went on a seaweed hunt to add to the samples collected by Caroline Pindar (https://seaweeddownsouth.wordpress.com/) earlier in the season. We dodged fur seals and chinstrap penguins and managed to find enough algae to fill seven bags, which are now frozen ready for their return to the UK in June.

 

We have also been testing the winches and running a test trawl at around 100m depth to iron out any problems with the equipment and to familiarize ourselves with the routines of sieving, sorting and cataloguing the animals we catch.

AS you can see from the picture below, there was plenty of mud! Once we washed and sieved it we found a wide  variety of species but not many individual animals of any. The highlight for me was finding the only  known species of pelagic bryozoan (Alcyonidium fabelliforme) which might look like a blob of jelly but is a colony of tiny animals closely related to “Dead Mens Fingers” that are found around the coasts of the UK.

Left- the trawl straight from the net Right – Pelagic bryozoan

We will start to survey and sample the designated sites tomorrow, weather permitting.

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Author: cathwaller

I'm an Antarctic ecologist working mainly on intertidal and nearshore ecosystems. I have worked at various locations around the Scotia Arc and Antarctic Peninsula. I am interested in what can survive in these environments, how things get there and how they might survive in a rapidly changing world.

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