High-latitude change

The sub-Arctic and Arctic regions are warming faster than the global average and the Arctic seawater pH is depressed relative to the global ocean.  Yet, these regions are data poor due to the logistical difficulties in monitoring environmental information prior to the advent of satellites.  My research works to understand the processes that drive high-latitude change through generation and interpretation of seawater reconstructions from the skeleton of coralline algae.

Funded by the National Science Foundation, I am currently working with Justin Ries at Northeastern University and post-doc Eleni Anagnostou (now at GEOMAR Helmholtz Centre for Ocean Research Kiel) to develop and use coralline algae as tools to trace high-latitude seawater pH variability.  This work is calibrating seawater pH to algal skeletal δ11B (Anagnostou et al., in press), as well as testing for impacts of seawater pH on the physical properties of the algal skeleton.

Using trace element composition of the coralline algae (Mg/Ca values), we have shown that variability in the northern North Pacific Ocean temperatures over the past century differs from prior natural variability (Williams et al., 2017).  This means that the period of time in which we have instrumental seawater temperature records is one in which anthropogenic climate change has already impacted the variability of this system in unique ways.

We have mapped changes in high-latitude seawater carbon chemistry in the Aleutian archipelago (Williams et al., 2011), and more recently in the northwest Atlantic (Hou et al., 2018 and Chan et al., 2017).