This is a blog entry I wrote for the Ocean Sampling Day (please see http://www.microb3.eu/osd for more information). We sample twice a year for the OSD and the filtered samples are frozen and send back for analysis.
|
Myself
and Amber taking water samples. (Photo: Peter Webster) |
Rothera is a British
Antarctic Survey research station, located on Adelaide Island on the Antarctic
Peninsula at 67° South (http://www.antarctica.ac.uk/living_and_working/research_stations/rothera).
Like last year, we were planning to get out on the actual Ocean Sampling Day
but where stopped by the weather and ice conditions. We had fast ice in Ryder
Bay which prevented us from
|
Sampling
by the ice edge with crabeater seals paying a visit. |
getting a boat in the water. However, as the ice
was staying longer and longer, we were getting very excited about the
possibility of doing a CTD and water sampling through the ice! When it was
finally signed off, we were ready to go but the wind once more was in our way.
Luckily, we were able to dive through the ice as it is closer to the shore and
less dangerous. Then, we experienced why Antarctica is called the windiest
continent on the planet. After a weekend of around 40-50 knots winds, half the
sea ice in Ryder Bay had been blown out. Luckily, this meant we were able to get
a boat into the water on the first calm day (just before the sea started
freezing again).
|
North
Cove is still covered in ice. |
We
got out to Site 2 (67°34.850
S, 68°09.340 W) on the 22nd of July. Site 2 is one of three sites
commonly used for the RaTS (Rothera Biological and Oceanographic Time Series)
sampling (see Picture 3). We sampled just on the edge of the fast ice. The day
started off very calm, but winds were picking up later on and finished just in
time before we would have had to abort the sampling. The air temperature was
only around -5°C. The water temperature was similar to last year -1.52°C. We
deployed the CTD to 300m and winched it back up again by hand. Afterwards we
collected water samples from 15m with our Niskin bottles.
|
Map of Ryder Bay showing the three CTD sites (open circles): 1 is the
main site (CTD1), 2 the secondary site (CTD2), and 3 is the fall-back site at
Biscoe Wharf (WS3). |
Same as last
year, we filtered 2l for each filter. However, on the ship last summer we
finally got some Sterivex filters in which we used (4 replicates). They were
frozen immediately with liquid nitrogen and are being stored in the -80°C
freezer until the ship next March picks them up together with the samples from
our Ocean Sampling Day in the summer.
The RaTS program includes various
aspects of sampling. With our CTD we measure depth, salinity, temperature, PAR
and fluorescence and the water samples we take back are mostly bottled up for
analysis back in the UK by a number of different institutes. We analyse
chlorophyll and ammonia in our lab here at Rothera. Whereas analysis for HPLC,
nutrients, CO2, salts, isotopes, DOC, viruses, Barium and
metagenomics is conducted elsewhere.
Sabrina
Heiser, Rothera Marine Assistant
Crew: Amber
Annett (Marine Assistant for the Dutch collaboration), Peter Webster (Diving
Officer)
(http://oceansamplingday.blogspot.co.uk/)