Biogeosciences,12,3351–3368,2015.PDFVIP

Biogeosciences, 12, 3351–3368, 2015 /12/3351/2015/ doi:10.5194/bg-12-3351-2015 © Author(s) 2015. CC Attribution 3.0 License. Environmental controls on the boron and strontium isotopic composition of aragonite shell material of cultured Arctica islandica 1 1 2 Y.-W. Liu , S. M. Aciego , and A. D. Wanamaker Jr. 1Department of Earth and Environmental Sciences, University of Michigan, 1100 N. University Avenue, Ann Arbor, MI 48109-1005, USA 2Department of Geological and Atmosphere Sciences, Iowa State University, Room 12, Science I, Ames, IA 50011-3212, USA Correspondence to: Y.-W. Liu (liuyiwei@) Received: 3 January 2015 – Published in Biogeosciences Discuss.: 10 February 2015 Revised: 23 April 2015 – Accepted: 6 May 2015 – Published: 4 June 2015 Abstract. Ocean acidification, the decrease in ocean pH as- anism only explains approximately 35 % of the variance in sociated with increasing atmospheric CO , is likely to im- the 11B data. Instead, a rapid rise in 11B of the shell ma- 2 pact marine organisms, particularly those that produce car- terial after week 19, during the summer, suggests that the bonate skeletons or shells. Therefore, it is important to in- boron uptake changes when a thermal threshold of 13 C vestigate how environmental factors (seawater pH, temper- is reached. ature and salinity) influence the chemical compositions in biogenic carbonates. In this study we report the first high- resolution strontium (87 Sr / 86 Sr and 88 86 Sr) and boron ( 11B) isotopic values in the aragonite shell of cultured Arc- 1 Introduction tica islandica (A. islandica). The 87 Sr 86 Sr ratios from both tank water and shell samples show ratios nearly identical to Since the onset of the Industrial Revolution (ca. AD 1750) the open ocean, which suggests