Entry 11
February 28 2025
'Drifting over the Lake District in an airship at a height of 3000 metres and trying to drop a rock onto a barn roof. At night' ~ Chief Scientist Jonathan Sharples
Having transited overnight to our ridge site, we arrived around 0400 and immediately set about getting the CTD in the water. Unfortunately we didn’t manage to get it out before dawn but it was a good day to have a bit of a play with methods - I was able to try out my new filtering rig, with the consensus being that you cannot filter 5L of seawater through a 0.2um filter under vacuum (at least, not in less than 5 hours!). So, lesson learned (the long way).
Filtering in hand, it was time to measure some chlorophylls - we were measuring total and size-fractionated chlorophyll, to enable us to understand the structure of the phytoplankton community in the water. We measure this with a spectrophotometer, once the filters have been in acetone for around a day after sampling. This measures the absorbance of light through the sample, from which we can understand how much of the chlorophyll pigment was present in the original filter.
Today we also dropped our second mooring – this time on the ridge. This works much the same as the first (see 25th Feb entry) except now we’re trying to drop the anchor on a specific location on this underwater mountain range. To quote our chief scientist, Jonathan, ‘it’s a bit like drifting over the Lake District in an airship at a height of 3000 metres trying to drop a rock onto a barn roof. At night.’ These two sets of moorings, together, will enable us to observe differences between the two sites – on and off the ridge.
In the evening (or, our version of evening, which is essentially 4-5pm) we were lucky enough to witness a part of the planetary parade - seeing Venus, Jupiter and Mars while the wirewalkers were deployed over the side.
