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A jolly to Bonne Bay to look for very small clams

on . Posted in Latest News



This week Becky, and Jason students of Suzanne Dufour kindly took me on a trip across the island to look for thyasirid clams. I was prepared for cold, unsuprised by ice on the ocean, unfazed by the winch not working, but no-one told me quite how small the little blighters are.


Our largest clam was about 7mm in maximum diameter, the mean size being about 1.5mm, and the smallest (collected primarily to test Jason's microdissection skills) was about 0.5mm. The location of their field area is Bonne Bay Marine Station, which is owned by Memorial University. Usually it is the focus of University and public training sessions but in the early winter there was just us and the year-round staff. Unsuprising really with ice on the bay, air temperatures of about 2oC, and water temperatures which felt like about -1oC.




Our first trip out on the bay sampling with Dennis our boatman was comparatively uneventful. We motored down to Southeast Arm on calm waters with scattered areas of slob ice. Sampling involved dropping a grab onto the seafloor and hauling it back up full of stinky black mud, tonnes of organic debris, and a fair amount of glacial outwash sediment, small pebbles and the like. Becky learnt that looking into the bucket as you slop out the sediment frlom the grab is not always a good plan (see photo to the left). We were restricted in our sampling by the bay being frozen up. Other than that it was idyllic, not a wave on the bay and only gulls and bald eagles for company.


Processing of the sediment samples involved wet sieving the sediment though a fine sive using freezing cold seawater so as not to upset the clams until they were ready for dissection. If the seidment wasn't full of pebbles, organic tat (twigs leafs), and a whole array of agglutinated tubes, the process of looking for the pearly white thyasirids would have been easy of cold. As it was we spent the afternoon with our hands in cold water until the light gave out and we gladly retreated to the warmth of the marine centre and the generously supplied kitchens (with deadly confectionary provided by Allison).






I am not sure who had the most rewarding time, the students or me. Becky was collecting material to augment her genetic studies of the thyasirids in the bay. Jason gave the impression that there was little he would rather do than pull the gils off of very small clams all night (to study their symbionts). I got to look at all kinds of agglutinated tubes foraminiferan and worm-made, there were all kinds of weird worms. Nothing makes an ichnologist happier than watching wierdy worms going about their business. I am no biologist, but I am pretty sure I collected siphunculids (3 types), Nermateans, a marine leech, an various nereiidid worms. They made it safely to my aquaria at MUN, we will have to see what they make of their new (rather sandy) homes.







So I learnt quite a bit in the course of our short trip:

1) Stay away from the bucket when the sediment is being slopped in

2) If you are to go on a marine biology fieldtrip in December you need neoprene gloves

3) If you stay at the Marine Station you need to work self restraint in the face of exceptional baking

4) Thyasirids are much smaller than they look in the literature

5) Microdissectionists are pretty damn skillful (Jason met my challenge of dissecting very very small clams without faltering).

6) Thyasirids and other associated chemosynthetic creatures are simply amazing.

7) next time I might try going out in the summer instead of December (we were very lucky with the weather)


Anyway, thanks to the students for putting up with my quizzing them on all kinds of obscure biological trivia, and to the kind welcoming staff at the marine centre.

I am enthused, and I will be back to play with odd worms, and help collect very small clams if needed