It all starts with the idea, a hypothesis really, that we are interested to know about the system of our investigation. The subjects of our investigation are pelagic calcifiers called pteropods (also sometimes called “sea butterflies”), that are put in an experimental setup in which we control a variety of different physical and chemical conditions.
Given that ocean conditions are becoming warmer and will have increased acidity in the future, we are exposing pteropods to acidified water, as well as ‘making them sweat’ under increased temperatures. My hypothesis is that pteropods will be significantly affected by the combined effects of ocean acidification and warming. We are studying whether these conditions dissolve their shells or decrease their survival rates, and how water masses impact gene distribution.
Setting up an experiment can be complicated anywhere. But making a successful experiment work on board a ship is, however, significantly different from laboratory work onshore where all pieces are at hand or a short drive away to a store. An at-sea experimentalist has to have it nailed down up to the last piece of tubing, hose clamp and connector; have all the chemical solutions prepared in advance and have all supplies ordered in a timely manner so they are ready before departure. If all the preparations on land run smoothly (which they almost never do) it can still take months to complete, with some serious multitasking in between and most of the time spent on the phone chasing down different companies to send the desired equipment as soon as possible.
The experimental set-up for pteropods also requires careful design as these beautiful creatures are extremely sensitive and difficult to maintain under laboratory conditions. Thus, we built flow-through systems in which seawater is brought onboard, the acidity increased by bubbling in CO2, and the water warmed to the desired temperature in large tanks. This water constantly flows through the smaller experimental chambers that the pteropods are temporarily living in. These chambers are huge for such small organisms, with a maximum expected size no larger than the head of a pin.
Our pteropod team consists of two members, Nina Bednarsek (UW), who is running the investigation, and Lisette Mekkes, a masters student from the University of Amsterdam who is assisting. But we have a lot of other helpers – seriously creative colleagues – who are all contributing to troubleshooting the system when needed.
Tomorrow is another net tow to catch these beautiful critters. And hopefully the system will be ready and waiting for the next batch of pteropods…
Author: Dr. Nina Bednarsek