2015年托福考试模拟题：阅读

　　2015年托福考试模拟题：阅读

　　ANALYTICAL METHODS

　　Analyses of all carbon parameters were performed following the techniques outlined in the "Handbook of Methods for the Analysis of the Various Parameters of the Carbon Dioxide System in Sea Water" (DOE 1994). Certified Reference Materials (CRMs) were used on all cruises as secondary standards for DIC, unless otherwise noted. Discussion of the preparation and use of CRMs is available in detail (UNESCO 1991; Dickson 1992; Dickson, Anderson, and Afghan, unpublished manuscript; Dickson, Afghan, and Anderson, unpublished manuscript). These materials consisted of a matrix of natural, sterile seawater. They were bottled in large batches into 500-mL borosilicate glass containers, sealed to prevent contamination, and shipped to the institutes participating in this study. These secondary standards were then analyzed at sea over the course of each of the cruises as a means to verify accuracy. Certification of the reference material

　　for DIC is based on manometric analyses in the shore-based laboratory of Charles D. Keeling of Scripps Institution of Oceanography (SIO) over a period of several months (UNESCO 1991; Guenther 1994; Keeling, C. D., personal communication, 1999). Since CRMs were analyzed routinely for DIC during most cruises used in this report, all groups analyzing for TAlk on those cruises subsequently analyzed CRMs as well; this enabled post-cruise corrections to be

　　made to the TAlk data based on archived samples that were analyzed at Dr. Keeling's laboratory at SIO. CRMs were not available for any other carbon parameter discussed in this report. Analyses of salinity and O2 followed WOCE Hydrographic Program (WHP) protocol