Most groups on board study things that are visible to the naked eye – whales, penguins, plankton, etc. These creatures are all part of the marine food web, and at the base is phytoplankton – the very small algae that photosynthesize. In addition to light, these plankton need carbon, nitrogen, phosphorus and a bunch of other elements in very small quantities to grow. Among these essential elements is iron (Fe). Iron is such a scarce nutrient that it can actually limit the growth of phytoplankton in some marine areas – including the Western Antarctic Peninsula. Because iron and many other elements (mercury, lead, zinc, etc.) occur in such small quantities we call them “trace” elements.
Trace elements are interesting because they can help us figure out why phytoplankton grown in certain areas but not others. Some of them can also help us figure out where they are coming from – dust blown over from South America and Australia, the weathering (“decay”) of the Antarctic continent, the melting of glaciers, or ocean currents which move south from lower latitudes.
In order to study these trace elements from a ship made of metal (inside and out!) many precautions are required to avoid contaminating seawater samples. These include using special metal-free collection bottles and a make-shift cleanroom made from wooden framing and plastic sheeting.
Rob Sherrell (Rutgers U., foreground) leads a deployment of the surface water sampler
Jess Fitzsimmons (Rutgers U.) sampling surface water, plumbed from the sampler off the side of the ship into the make-shift clean room
The “trace elements” team prepares the water collection bottles for a cast into the ocean
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