Keeping the Glass Half Full
Braving the elements is one rite of passage to becoming an oceanographer. I discovered this generational tradition yesterday as I helped Phoebe and Dan, my research team, sample our last subtropical station of the western Indian Ocean. The Revelle was passing through a storm, a low pressure zone of the ugliest character: grey thundering skies, sheets of rain, deafening wind and frothy wave crests crashing over our rubber boots on deck.
Studying the ocean is a delicate balance between organization and improvisation. On one hand, the science crew on board follows a strict schedule of sampling and in-lab testing. For example, my group takes ocean samples about every other day; our time is split between preparing for these sampling stations as well as doing immediate chemistry on the seawater we collect. With just 5 weeks on board, we aim to collect and process roughly 300 samples of seawater particles to measure carbon and thorium. About 18 hours in the day are utilized cumulatively among the three of us to get this done.
At the same time, the sea changes constantly. The size of the waves from Durban until now has probably doubled (grip pads are now on every meal table!), and last night the temperature dropped drastically as we descended southward in latitude. These changes are foreseeable, but there is always an element of uncertainty as the Revelle plows through mountains of waves and different weather zones. Fast decision-making is equally necessary for the organized scientist.
Dan says casual whistling on a ship always jinxes something, so that most likely explains why the storm picked up just as we deployed our first instrument into the water. The instruments we lower are heavy battery-powered pumps programmed to pump high volumes of water through a labyrinth of plastic tubing. At the end of these tubes are large filters that collect the solid particles suspended in seawater. Ultimately, Phoebe, Dan and I will measure the metal content, carbon content and thorium radioactivity in these particles.
Considering the weight, price and academic value of these pumps – not too mention the futility of our rubber boots against the wave crests – there were several risks in descending eight of them on a Kevlar wire. As the weather worsened, we were forced to abandon the cast, though thankfully not to abandon ship. We deployed a quicker CTD cast shortly after, as a last-minute make-up for our losses. But the CTD rosette collects at most 360 liters of unfiltered seawater at a given depth, while each pump alone filters two to three times that volume underwater, leaving us with only half the intended volume at one of the eight intended depths. Fortunately, improvisation has its way of keeping the glass half full even when crazy waves are trying to topple it over. At the end of our day, that was one less data sample lost to the elements.