Thursday 14th February

Today an almost-forgotten friend renewed their acquaintance: the weather.

Usually on seagoing research expeditions, the daily science meeting starts with an update on the weather forecast, which often determines the course of action for the next 24 hours. But here in the Caribbean in February, we have hardly had to consider the weather, which has been repetitively calm. The weather, however, mocks those who take it for granted.

The forecast now shows conditions deteriorating over the weekend, and likely to become marginal for launching the ROV. Precise prediction is difficult, because what governs whether or not we can dive is the sea state: a combination of wind speed and direction, wave height, and currents.

RRS James Cook location seen from space this morning

Originally I had planned to follow our ROV dives at the Von Damm Field with 48 hours of hydrographic surveying, giving us time to take stock of our progress before beginning our dive programme at the world's deepest known vents. But hydrographic surveying is less constrained by the weather than ROV diving. It therefore makes sense to reschedule our hydrographic work for when the weather may prevent us from diving, rather than now.

So after Isis dive 202 returns to the ship, we will head straight for the Beebe Vent Field, which lies at a depth of 5 km in the centre of the volcanic rift. We should be able to complete our first few tasks there before the weather breaks, at which point we will switch to our hydrographic survey. Meanwhile, Isis dive 202 is collecting the final data and samples at the Von Damm Vent Field. When this dive achieves all of its objectives, each science team should have a full suite of evidence to understand the different aspects of these very unusual deep-sea vents.

It is hard to believe that we have only been working here for one week; the routine of life aboard is already engrained, and our small community feels long-established. But although we are not yet half way through our expedition time, the end already seems to be rushing towards us in our plans.

February 2013