0000000000270522
AUTHOR
Branwen Williams
Freshening of the Alaska Coastal Current recorded by coralline algal Ba/Ca ratios
Arctic Ocean freshening can exert a controlling influence on global climate, triggering strong feedbacks on ocean‐atmospheric processes and affecting the global cycling of the world’s oceans. Glacier‐fed ocean currents such as the Alaska Coastal Current are important sources of freshwater for the Bering Sea shelf, and may also influence the Arctic Ocean freshwater budget. Instrumental data indicate a multiyear freshening episode of the Alaska Coastal Current in the early 21st century. It is uncertain whether this freshening is part of natural multidecadal climate variability or a unique feature of anthropogenically induced warming. In order to answer this, a better understanding of past var…
Coralline algal growth-increment widths archive North Atlantic climate variability
Over the past decade coralline algae have increasingly been used as archives of paleoclimate information. Encrusting coralline algae, which deposit annual growth increments in a high Mg-calcite skeleton, are amongst the longest-lived shallow marine organisms. In fact, a live-collected plant has recently been shown to have lived for at least 850 years based on radiometric dating. While a number of investigations have successfully used geochemical information of coralline algal skeletons to reconstruct sea surface temperatures, less attention has been paid to employ growth increment widths as a temperature proxy. Here we explore the relationship between growth and environmental parameters in …
Historical Contaminant Records from Sclerochronological Archives
A number of marine and freshwater organisms, including scleractinian and proteinacious corals, coralline algae, sclerosponges, and bivalve mollusks, secrete skeletons that grow larger over time and may record environmental contaminants over the lifespan of an individual. Most of these organisms also form periodic growth patterns (growth increments, lines or bands) that can be used to accurately date contaminant archives produced from chemical or physical analysis of sequential skeletal samples (termed sclerochronology). The majority of records produced from these organisms thus far have focused on paleoclimate reconstructions, but there is a vast potential for information on changes in cont…