An Annually-Resolved, Shell-Derived Oxygen Isotope Record Since the Late Little Ice Age from the Gulf of Maine: Implications for Ocean Circulation Changes in the Northwestern North Atlantic

North Atlantic ocean circulation is known to significantly affect the earth's climate. However, the scarcity of long-term, high-resolution, precisely-dated marine records in the region makes it difficult to interpret past ocean circulation changes and the mechanisms by which these changes influenced global climate. In this study, we present an annually-resolved oxygen isotope record from the northwestern North Atlantic since the late Little Ice Age. This record was developed from crossdated Arctica islandica shells collected near Seguin Island in the western Gulf of Maine in 38 meters water depth.

The shell-derived oxygen isotope record suggests decadal- to multidecadal-scale oscillations in hydrography and seawater temperatures likely related to changes in the position and properties of the Gulf Stream and the Labrador Current. The relationships between the Gulf of Maine oxygen isotope record and seawater temperature records from the subpolar gyre region of the North Atlantic and the northwestern North Atlantic are similar in pattern to the modeled and observed influence of the Atlantic meridional overturning circulation (AMOC) on seawater temperatures in these regions. This similarity suggests a possible association between surface AMOC variability and seawater temperatures in the Gulf of Maine. The shell-derived oxygen isotope record is consistent with an increased strength of the AMOC after the Little Ice Age. As we extend the record back in time, these annually resolved and precisely dated oxygen isotope data will likely yield information regarding the state of the surface AMOC during the last millennium.