Tracking the Impact of Climate Change on Marine Animals

A woman wearing a yellow jacket and red life vest looking forward off the bow of a boat toward rocky shoreline.

This is the eighth in a series of posts by Associate Curator of Invertebrate Zoology Janet R. Voight as she heads out on an expedition to Norway. There, she and colleagues will look for a wood-boring clam, Xylophaga dorsalis, to study its, well, poo. Read the first post and stay tuned for upcoming posts to find out what they discover.

Climate change is the basis of this expedition: we are setting out to learn more about the clam Xylophaga dorsalis in Norway before it spreads. It has the potential to become an invasive species in the Arctic, which we hypothesize is a pristine habitat. In an earlier post, I mentioned Professor Torleiv Brattegard, who has recorded collections of marine animals in Norway throughout his career and has earlier records that we’re able to refer to. These show that Xylophaga dorsalis was collected here in the 1950s, and we know it was present about 300 miles north in the 1970s. That is critical information to me, but I’m rather focused (who else do you know who is into wood-boring clams?).  

In 2011, Prof. Brattegard and a colleague published a list of 1,600 benthic Norway species and their distributions from 1997 to 2010. They reported that 100 species from more temperate areas had moved in, and 565 species from southern areas moved at least 750 km, or over 465 miles, north. The list is not necessarily definitive—the authors aren’t trying to say that they know everything about all the animals in the sea—but there appears to be a clear signal that we need to pay attention to this.  

Only with long-term monitoring, accurate species identifications, and comparisons over fairly long timescales can such subtle impacts of climate change be seen in the marine realm. The effort (and years) it takes to generate such a list, however, are not only unsung, but the effort may even be derided as unproductive in today’s increasingly competitive scientific milieu. When it does pay off, it may come too late. But it does identify what to look for as potential indicators of faunal change farther north. Ideally, it will encourage other researchers to check their own records or their specimens that have accurate locality data and collection dates, such as those in museum collections. Professor Brattegard’s list of occurrences is a set of 665 hypotheses, one for each species with a reported change in its range. Other scientists may test each hypothesis; testing hypotheses is critical to science.

On this trip, we’re trying to test the hypothesis of increasing range of wood-borers by collecting wood that has been cast up on the shore or wedged between rocks in the intertidal. We don’t know if our target species will be here, but I know they have been recorded from the intertidal zone in Britain. No one is apt to have looked here. Finding wood borers takes dedicated effort. One has to WANT to find them, since they bore into solid wood that remains hard, even after the borers have made Swiss cheese out of parts of it. What will we find after days of hiking over unstable rocks and carrying water-logged wood back to the marine station, then beating it with a chisel and mallet?

Read on in Part 9: Chisels, Hammers, and Science: Woodworking for Clams

Funding for this project was provided by the Robert A. Pritzker Center for Meteoritics and Polar Studies established by a grant from the Tawani Foundation.