(Table S1) Stable isotope record and growth rates of cultured Mytilus edulis

To study the effects of temperature, salinity, and life processes (growth rates, size, metabolic effects, and physiological/genetic effects) on newly precipitated bivalve carbonate, we quantified shell isotopic chemistry of adult and juvenile animals of the intertidal bivalve Mytilus edulis (Blue mussel) collected alive from western Greenland and the central Gulf of Maine and cultured them under controlled conditions. Data for juvenile and adult M. edulis bivalves cultured in this study, and previously by Wanamaker et al. (2006, doi:10.1029/2005GC001189), yielded statistically identical paleotemperature relationships. On the basis of these experiments we have developed a species-specific paleotemperature equation for the bivalve M. edulis [T °C = 16.28 (±0.10) - 4.57 (±0.15) {d18Oc VPBD - d18Ow VSMOW} + 0.06 (±0.06) {d18Oc VPBD - d18Ow VSMOW}**2; r**2 = 0.99; N = 323; p < 0.0001]. Compared to the Kim and O'Neil (1997) inorganic calcite equation, M. edulis deposits its shell in isotope equilibrium (d18Ocalcite) with ambient water. Carbon isotopes (d13Ccalcite) from sampled shells were substantially more negative than predicted values, indicating an uptake of metabolic carbon into shell carbonate, and d13Ccalcite disequilibrium increased with increasing salinity. Sampled shells of M. edulis showed no significant trends in d18Ocalcite based on size, cultured growth rates, or geographic collection location, suggesting that vital effects do not affect d18Ocalcite in M. edulis. The broad modern and paleogeographic distribution of this bivalve, its abundance during the Holocene, and the lack of an intraspecies physiologic isotope effect demonstrated here make it an ideal nearshore paleoceanographic proxy throughout much of the North Atlantic Ocean.

为探究温度、盐度及生命过程（生长速率、个体大小、代谢效应及生理/遗传效应）对新沉积双壳类贝壳碳酸盐的影响，本研究对从格陵兰西部与缅因湾中部鲜活采集的潮间带双壳类紫贻贝（Mytilus edulis，俗称蓝贻贝Blue mussel）的成体与幼体个体开展了贝壳同位素化学组成的定量分析，并在受控培养条件下对其进行培育。本研究及此前Wanamaker等人（2006，doi:10.1029/2005GC001189）所开展的紫贻贝成体与幼体培养实验数据，得到了统计学上一致的古温度关系。基于上述实验，本研究建立了针对紫贻贝的物种特异性古温度方程：T(℃) = 16.28(±0.10) - 4.57(±0.15){δ¹⁸Oc VPDB - δ¹⁸Ow VSMOW} + 0.06(±0.06){δ¹⁸Oc VPDB - δ¹⁸Ow VSMOW}²；r²=0.99；N=323；p<0.0001。相较于Kim与O'Neil（1997）提出的无机方解石方程，紫贻贝贝壳沉积时的方解石氧同位素（δ¹⁸Ocalcite）与周围水体处于同位素平衡状态。采样贝壳的碳同位素（δ¹³Ccalcite）显著低于预测值，表明代谢碳被纳入贝壳碳酸盐中，且碳同位素失衡程度随盐度升高而加剧。采样紫贻贝贝壳的δ¹⁸Ocalcite并未随个体大小、培养生长速率或采集地理区位出现显著变化趋势，表明生命效应对紫贻贝的δ¹⁸Ocalcite无显著影响。该双壳类现生及古地理分布范围广泛，在全新世地层中含量丰富，且本研究证实其不存在种内生理同位素效应，因此它是北大西洋多数近岸海域理想的古海洋学代用指标。