A COMPARISON OF HOLOCENE LAND AND SEA SURFACE TEMPERATURE FROM THE GULF OF MAINE BASED ON GDGTS AND ALKENONES

The Gulf of Maine is located on the North American shelf, and stretches from the Bay of Fundy and Nova Scotia in the north to Cape Cod, Massachusetts, in the south. Its watershed comprises all of Maine, 70% of New Hampshire, 56% of New Brunswick, 41% of Massachusetts, and 36% of Nova Scotia suggesting its sediments record a history representative of most of the Northeast U.S.A. The Gulf of Maine is one of the most productive fisheries in the North Atlantic Ocean, and is an important summering ground for many species of whale. However, the Gulf of Maine is currently warming faster than 99% of the Earth’s oceans. This has already resulted in northward shifts of many commercially valuable fish species and increased mortality rates of others. Modern rates of change in the Gulf of Maine suggest it is particularly sensitive to modern climate change and, by extension, climate changes in the past, making it ideal for paleoceanographic investigation. Here we present results of land and sea surface temperature determinations from a marginal sediment core (CH-10-90 PC-3; Jordan Basin, NE Gulf of Maine) based on GDGTs (MBT/CBT) and alkenones (U_k’³⁷), respectively. Alkenone-based sea surface temperature (SST) estimates suggest the Gulf of Maine cooled almost 5°C over the past 8 kyr, closely paced by insolation. Comparison of U_k’³⁷ and MBT/CBT temperature estimates highlight changing land-sea temperature gradients with implications for regional atmospheric dynamics (NAO and NAO-like climate variability).