Amchitka Island Alaska 65 Year Corraline Algae Mg/Ca Data Hetzinger, S.; Halfar, J.; Kronz, A.; Steneck, R.S.; Adey, W.; Lebednik, P.; Schöne, B.R. Hetzinger, S. Halfar, J. Kronz, A. Steneck, R.S. Adey, W. Lebednik, P. Schöne, B.R. PAGES 2k Network PAGES Ocean 2k earth science/paleoclimate/corals and sclerosponges (magnesium/calcium,Clathromorphum nereostratum,null,dimensionless,null,corals and sclerosponges,null,null,N,coralline red algae species) earth science/paleoclimate/paleoceanography (age,null,null,year Common Era,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean (Kirlof Point, Amchitka Island>LATITUDE 51.4156>LONGITUDE 179.2996) We present the first continuous, high-resolution record of Mg/Ca variations within an encrusting coralline red alga, Clathromorphum nereostratum, from Amchitka Island, Aleutian Islands. Mg/Ca ratios of individual growth increments were analyzed by measuring a single-point, electron-microprobe transect, yielding a resolution of ~15 samples/year and a 65-year record (1902-1967) of variations. Results show that Mg/Ca ratios in the high-Mg calcite algal framework display pronounced annual cyclicity and archive late spring-late fall sea-surface temperatures (SST) corresponding to the main season of algal growth. Mg/Ca values correlate well to local SST, as well as to an air temperature record from the same region. High spatial correlation to large-scale SST variability in the subarctic North Pacific is observed, with patterns of strongest correlation following the direction of major oceanographic features that play a key role in the exchange of water masses between the North Pacific and the Bering Sea. Our data correlate well with a shorter Mg/Ca record from a second site, corroborating the ability of the alga to reliably record regional environmental signals. In addition, Mg/Ca ratios relate well to a 29-year d18O time series measured on the same sample, providing additional support for the use of Mg in coralline red algae as a paleotemperature proxy that, unlike algal-d18O, is not influenced by salinity fluctuations. Moreover, electron microprobe-based analysis enables higher sampling resolution and faster analysis, thus providing a promising approach for future studies of longer C. nereostratum records and applications to other coralline species. STUDY NOTES: 65 year Mg/Ca data from coralline alga collected near Amchitka Island, Aleutian Islands, Alaska. C. nereostratum is a long-lived, shallow-marine crustose coralline algae. Specimen AM-KR-80 8-69-14B collected in August 1969, 25 water depth, coralline algae, species: Clathromorphum nereostratum Sampling location: Kirlof Point, Amchitka Island, Alaska, 51°24.936'N, 179°17.976'E. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Hetzinger, S. Investigator : Halfar, J. Investigator : Kronz, A. Investigator : Steneck, R.S. Investigator : Adey, W. Investigator : Lebednik, P. Investigator : Schöne, B.R. 2012-04-02 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/12888 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hetzinger2009/hetzinger2009.xls https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hetzinger2009/hetzinger2009.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hetzinger2009/hetzinger2009.xls https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hetzinger2009/hetzinger2009.txt English https://www.ncdc.noaa.gov/paleo/study/12888 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hetzinger2009/hetzinger2009.xls https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/hetzinger2009/hetzinger2009.txt Hetzinger, S., J. Halfar, A. Kronz, R.S. Steneck, W. Adey, P.A. Lebednik, and B.R. Schöne. 2009. High-Resolution Mg/Ca Ratios in a Coralline Red Alga as a Proxy for Bering Sea Temperature variations from 1902 to 1967. Palaios, June 2009, Vol. 24, no. 6, pp. 406-412. doi: 10.2110/palo.2008.p08-116r http://palaios.geoscienceworld.org/content/24/6/406.abstract START YEAR: 1902 AD * END YEAR: 1967 AD 179.2996 51.4156 179.2996 51.4156