@article {2701, title = {Pacific climate influences on ocean conditions and extreme shell growth events in the Northwestern Atlantic (Gulf of Maine)}, journal = {Climate Dynamics}, volume = {52}, year = {2019}, month = {Jan-06-2019}, pages = {6339 - 6356}, abstract = {The Gulf of Maine is undergoing rapid environmental and ecological changes, yet our spatial and temporal understanding of the climatic and hydrographic variability in this region, including extreme events, is limited and biased to recent decades. In this study, we utilize a highly replicated, multi-century master shell growth chronology derived from the annual increments formed in the shells of the long-lived bivalve Arctica islandica collected in 38 m from the central coastal region in the Gulf of Maine. Our results indicate that shell growth is highly synchronous and inversely related to local seawater temperatures. Using composite analyses of extreme shell growth events from CE 1900 to 2013, we extend our understanding of the factors driving oceanic variability and shell growth in the Northwestern Atlantic back to CE 1761. We suggest that extreme shell growth events are primarily controlled by Gulf of Maine sea surface temperature (SST) and stratification conditions, which in turn appear to be largely influenced by SST patterns in the Pacific Ocean through their influence on mid-latitude atmospheric circulation patterns and the location of the eddy-driven jet. The large-scale jet dynamics during these extreme years manifest as precipitation and moisture transport anomalies and regional SST conditions in the Gulf of Maine that either enhance or inhibit shell growth. Pacific climate variability is thus an important, yet understudied, influence on Gulf of Maine ocean conditions.}, issn = {0930-7575}, doi = {10.1007/s00382-018-4513-8}, url = {https://link.springer.com/article/10.1007/s00382-018-4513-8}, author = {Wanamaker, Alan D. and Griffin, Shelly M. and Ummenhofer, Caroline C. and Whitney, Nina M. and Black, Bryan and Parfitt, Rhys and Lower-Spies, Erin E. and Introne, Douglas and Kreutz, Karl J.} } @article {170, title = {Gulf of Maine shells reveal changes in seawater temperature seasonality during the Medieval Climate Anomaly and the Little Ice Age}, journal = {Reconstructing mid- to high-latitude marine climate and ocean variability using bivalves, coralline algae, and marine sediment cores from the Northern Hemisphere}, volume = {302}, year = {2011}, note = {id: 2193}, pages = {43-51}, abstract = {In this study, we use subannually resolved oxygen isotope values of fossil (dead-collected) and modern (live-caught) bivalve shells (Arctica islandica L.) from the northwestern Atlantic (Gulf of Maine, USA) to reconstruct past seasonal changes in seawater temperature. Our results indicate decreased seasonal temperature amplitude of about 1.6 {\textdegree}C (or \~{} 21\%) during Medieval times (ca. AD 1033{\textendash}1062) compared to shells from the early Little Ice Age (ca. AD 1321{\textendash}1391) and during the late 19th century (AD 1864{\textendash}1886). Additionally, seasonal oxygen isotope data suggest that summers were cooler and winters were warmer in the Gulf of Maine during the 11th century compared to summers and winters in the 14th century and the late 19th century. The inferred decreased seasonality during Medieval times likely resulted from increased stratification of the coastal waters due to warmer seawater temperatures. As seawater cooled during the Little Ice Age, we suggest that increased vertical mixing of the coastal surface waters was a major driving factor for the observed increase in the amplitude of the seasonal seawater temperature cycle.}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2010.06.005}, url = {http://www.sciencedirect.com/science/article/pii/S0031018210003378}, author = {Wanamaker Jr, Alan D. and Kreutz, Karl J. and Sch{\"o}ne, Bernd R. and Introne, Douglas S.} } @article { ISI:000262579500003, title = {A late Holocene paleo-productivity record in the western Gulf of Maine, USA, inferred from growth histories of the long-lived ocean quahog (Arctica islandica)}, journal = {INTERNATIONAL JOURNAL OF EARTH SCIENCES}, volume = {98}, number = {{1}}, year = {2009}, month = {FEB}, pages = {19-29}, type = {Article}, abstract = {To investigate environmental variability during the late Holocene in the western Gulf of Maine, USA, we collected a 142-year-old living bivalve (Arctica islandica) in 2004, and three fossil A. islandica shells of the Medieval Warm Period (MWP) and late MWP / Little Ice Age (LIA) period (corrected C-14(AMS) = 1030 +/- A 78 ad; 1320 +/- A 45 ad; 1357 +/- A 40 ad) in 1996. We compared the growth record of the modern shell with continuous plankton recorder (CPR) time-series (1961-2003) from the Gulf of Maine. A significant correlation (r (2) = 0.55; p < 0.0001) exists between the standardized annual growth index (SGI) of the modern shell and the relative abundance of zooplankton species Calanus finmarchicus. We therefore propose that SGI data from A. islandica is a valid proxy for paleo-productivity of at least one major zooplankton taxa. SGIs from these shells reveal significant periods of 2-6 years (NAO-like) based on wavelet analysis, multitaper method (MTM) analysis and singular spectrum analysis (SSA) during the late Holocene. Based on established physical oceanographic observation in the Gulf of Maine, we suggest that slope water variability coupled with North Atlantic Oscillation (NAO) dynamics is primarily responsible for the observed SGI variability.}, keywords = {Arctica islandica, Climate variability, Gulf of Maine, North Atlantic Oscillation (NAO), Paleo-productivity, Shell growth}, issn = {1437-3254}, doi = {10.1007/s00531-008-0318-z}, author = {Wanamaker, Alan D. Jr. and Kreutz, Karl J. and Schoene, Bernd R. and Maasch, Kirk A. and Pershing, Andrew J. and Borns, Harold W. and Introne, Douglas S. and Feindel, Scott} } @article {2540, title = {Coupled North Atlantic slope water forcing on Gulf of Maine temperatures over the past millennium}, journal = {Climate Dynamics}, volume = {31}, year = {2008}, month = {Jan-08-2008}, pages = {183 - 194}, abstract = {To investigate ocean variability during the last millennium in the Western Gulf of Maine (GOM), we collected a 142-year-old living bivalve (Arctica islandica L.) in 2004, and three fossil A. islandica shells (calibrated 14CAMS = 1030 {\textpm} 78 ad; 1320 {\textpm} 45 ad; 1357 {\textpm} 40 ad) for stable isotope and growth increment analysis. A statistically significant relationship exists between modern GOM temperature records [shell isotope-derived (30 m) (r = -0.79; P < 0.007), Prince 5 (50 m) (r = -0.72; P < 0.019), Boothbay Harbor SST (r = -0.76; P < 0.011)], and Labrador Current (LC) transport data from the Eastern Newfoundland Slope during 1993{\textendash}2003. In all cases, as LC transport increased, GOM water temperatures decreased the following year. Decadal trends in the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO) influence GOM water temperatures in the most recent period, with water temperatures decreasing during NAO and AMO negative modes most likely linked to LC transport and Gulf Stream interaction. Mean shell-derived isotopic changes (δ18Oc) during the last 1,000 years were +0.47{\textperthousand} and likely reflect a 1{\textendash}2{\textdegree}C cooling from 1000 ad to present. Based on these results, we suggest that observed cooling in the GOM during the last millennium was due to increased transport and/or cooling of the LC, and decreased Gulf Stream influence on the GOM.}, issn = {0930-7575}, doi = {10.1007/s00382-007-0344-8}, url = {http://www.springerlink.com/index/pdf/10.1007/s00382-007-0344-8}, author = {Wanamaker, Alan D. and Kreutz, Karl J. and {\"o}ne, Bernd R. and Pettigrew, Neal and Borns, Harold W. and Introne, Douglas S. and Belknap, Daniel and Maasch, Kirk A. and Feindel, Scott} }