# Arctic and North Atlantic 1979-2015 Coralline Red Algae Annual Growth and Mg/Ca Data #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program # National Centers for Environmental Information (NCEI) #----------------------------------------------------------------------- # Template Version 3.0 # Encoding: UTF-8 # NOTE: Please cite Publication, and Online_Resource and date accessed when using these data. # If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed. # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/34994 # Description: # Online_Resource: https://www.ncei.noaa.gov/pub/data/paleo/contributions_by_author/leclerc2022/16_24_15_Mg_Ca_repository.txt # Description: # # Original_Source_URL: # Description: # # Description/Documentation lines begin with # # Data lines have no # # # Data_Type: corals and sclerosponges # # Dataset_DOI: # # Parameter_Keywords: sea ice, sea surface temperature, width, sclerochronology #-------------------- # Contribution_Date # Date: 2021-11-24 #-------------------- # File_Last_Modified_Date # Date: 2021-11-24 #-------------------- # Title # Study_Name: Arctic and North Atlantic 1979-2015 Coralline Red Algae Annual Growth and Mg/Ca Data #-------------------- # Investigators # Investigators: Leclerc, N.; Halfar, J.; Hetzinger, S.; Chan, P.P.T.W.; Adey, W.; Tsay, A.; Brossier, E.; Kronz, A. #-------------------- # Description_Notes_and_Keywords # Description: Annual growth widths and Mg/Ca ratios of Coralline red algae Clathromorphum compactum in Arctic and North Atlantic Oceans from 1979 to 2015. # These data are the calculated anomalies of annual growth increments and Mg/Ca cycles from the long-lived annual increment-forming benthic coralline red alga, # Clathromorphum compactum. Laser-ablation inductively-coupled mass spectrometry was used to measure trace elements along the axis of growth, and annual cycles # of magnesium-calcium ratios were used in conjunction with visual growth increments to determine annual growth increments. Growth increment widths were # measured between two adjacent Mg/Ca minima and determined as 1-year cycles. One-year Mg/Ca cycles and visual growth increment identification were used # in the construction of chronology. Resulting Mg/Ca data for all analyzed specimens was down-sampled to 12 measurements/year resolution. # When two measurement transects were taken from a sample, annual growth increment widths and Mg/Ca ratios were averaged between transects # and were compared to aid in the construction of age models. These data were collected to establish whether they could be used as # paleo-environmental proxies, specifically as sea ice concentration and sea surface temperature. They have been compared to satellite datasets (1979-2015). #-------------------- # Publication # Authors: Natasha Leclerc, Jochen Halfar, Steffen Hetzinger, Phoebe T.W. Chan, Walter Adey, Alexandra Tsay, Eric Brossier, Andreas Kronz # Published_Date_or_Year: 2022-01-01 # Published_Title: Suitability of the Coralline Alga Clathromorphum compactum as an Arctic Archive for Past Sea ice Cover # Journal_Name: Paleoceanography and Paleoclimatology # Volume: 37 # Edition: e2021PA004286 # Issue: 1 # Pages: # Report_Number: # DOI: 10.1029/2021PA004286 # Online_Resource: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021PA004286 # Full_Citation: # Abstract: Arctic sea ice cover has been steeply declining since the onset of satellite observations in the late 1970s. However, the available annually resolved sea ice data before this time are limited. Here, we evaluated the suitability of annual trace element (Mg/Ca) ratios and growth increments from the long-lived annual increment-forming benthic coralline red alga, Clathromorphum compactum, as high-resolution sea ice cover archive. It has previously been shown that the growth of C. compactum is strongly light controlled and therefore greatly limited during the polar night and underneath sea ice cover. We compare algal data from 11 sites collected throughout the Canadian Arctic, Greenland, and Svalbard, with satellite sea ice data. Our results suggested that algal growth anomalies most often produced better correlations to sea ice concentration than Mg/Ca ratios or when averaging growth and Mg/Ca anomalies. High Arctic regions with persistently higher sea ice concentrations and shorter ice-free seasons showed the strongest correlations between algal growth anomalies and satellite sea ice concentration over the study period (1979-2015). At sites where ice breakup took place before the return of sufficient solar irradiance, algal growth was most strongly tied to a combination of solar irradiance and other factors such as temperature, suspended sediments, phytoplankton blooms, and cloud cover. These data are the only annually resolved in situ marine proxy data known to date and are of utmost importance to gain a better understanding of the sea ice system and to project future sea ice conditions. #--------------------------------------- # Publication # Authors: Jochen Halfar, Walter H. Adey, Andreas Kronz, Steffen Hetzinger, Evan Edinger, and William W. Fitzhugh # Published_Date_or_Year: 2013-11-18 # Published_Title: Arctic sea-ice decline archived by multicentury annual-resolution record from crustose coralline algal proxy # Journal_Name: Proceedings National Academy of Sciences # Volume: # Issue: # Pages: # Report Number: # DOI: www.pnas.org/cgi/doi/10.1073/pnas.1313775110 # Abstract: Northern Hemisphere sea ice has been declining sharply over the past decades and 2012 exhibited the lowest Arctic summer sea-ice cover in historic times. Whereas ongoing changes are closely monitored through satellite observations, we have only limited data of past Arctic sea-ice cover derived from short historical records, indirect terrestrial proxies, and low-resolution marine sediment cores. A multicentury time series from extremely long-lived annual increment-forming crustose coralline algal buildups now provides the first high-resolution in situ marine proxy for sea-ice cover. Growth and Mg/Ca ratios of these Arctic-wide occurring calcified algae are sensitive to changes in both temperature and solar radiation. Growth sharply declines with increasing sea-ice blockage of light from the benthic algal habitat. The 646-y multisite record from the Canadian Arctic indicates that during the Little Ice Age, sea ice was extensive but highly variable on subdecadal time scales and coincided with an expansion of ice-dependent Thule/Labrador Inuit sea mammal hunters in the region. The past 150 y instead have been characterized by sea ice exhibiting multidecadal variability with a long-term decline distinctly steeper than at any time since the 14th century. #--------------------------------------- # Publication # Authors: Steffen Hetzinger, Jochen Halfar, Zoltán Zajacz, Max Wisshak # Published_Date_or_Year: 2019-08-30 # Published_Title: Early start of 20th-century Arctic sea-ice decline recorded in Svalbard coralline algae # Journal_Name: Geology # Volume: 47 # Edition: # Issue: 10 # Pages: 963-967 # Report_Number: # DOI: 10.1130/G46507.1 # Online_Resource: https://pubs.geoscienceworld.org/gsa/geology/article/47/10/963/573355/Early-start-of-20th-century-Arctic-sea-ice-decline # Full_Citation: # Abstract: The fast decline of Arctic sea ice is a leading indicator of ongoing global climate change and is receiving substantial public and scientific attention. Projections suggest that Arctic summer sea ice may virtually disappear within the course of the next 50 or even 30 yr with rapid Arctic warming. However, limited observational records and lack of annual-resolution marine sea-ice proxies hamper the assessment of long-term changes in sea ice, leading to large uncertainties in predictions of its future evolution under global warming. Here, we use long-lived encrusting coralline algae that strongly depend on light availability as a new in situ proxy to reconstruct past variability in the duration of seasonal sea-ice cover. Our data represent the northernmost annual-resolution marine sea-ice reconstruction to date, extending to the early 19th century off Svalbard. Algal records show that the decreasing trend in sea-ice cover in the high Arctic had already started at the beginning of the 20th century, earlier than previously reported from sea-ice reconstructions based on terrestrial archives. Our data further suggest that, although sea-ice extent varies on multidecadal time scales, the lowest sea-ice values within the past 200 yr occurred at the end of the 20th century. #------------------ # Funding_Agency # Funding_Agency_Name: Natural Sciences and Engineering Research Council # Grant: NSERC Discovery 1303409, NSERC CGSD3- 518838 - 2018 #------------------ # Site_Information # Site_Name: Beechey Island # Location: Ocean>Atlantic Ocean>North Atlantic Ocean # Northernmost_Latitude: 74.715127 # Southernmost_Latitude: 74.715127 # Easternmost_Longitude: -91.791486 # Westernmost_Longitude: -91.7914861 # Elevation: #------------------ # Data_Collection # Collection_Name: 16_24_15 # Earliest_Year: 1979 # Most_Recent_Year: 2015 # Time_Unit: year Common Era # Core_Length: # Notes: Sample collected in June 2016 (2016 is a partial year and therefore not included in dataset) #------------------ # Chronology_Information # Chronology: Chronology based on visual identification of annual increments and annual cycles of trace element ratios (Mg/Ca) # #---------------- # Variables # # Data variables follow are preceded by "##" in columns one and two. # Data line variables format: one per line, shortname-tab-variable components (what, material, error, units, seasonality, data type,detail, method, C or N for Character or Numeric data, free text) # ## age_CE age, , , year Common Era, , corals and sclerosponges, , ,N, ## MgCa-anom magnesium/calcium, Clathromorphum compactum, , standard deviation units, , corals and sclerosponges, normalized, ,N, annual anomaly = annual Mg/Ca (ratio) - 1979-2015 average Mg/Ca (ratio) / 1979-2015 standard deviation # #---------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Values: # 2015 2.327000906 2014 0.440825613 2013 -0.227938342 2012 0.686244338 2011 0.684105122 2010 0.272727923 2009 0.521586276 2008 0.394944649 2007 1.97711711 2006 1.300333229 2005 0.957260826 2004 0.061876861 2003 -0.689449599 2002 -0.653642107 2001 -1.015053219 2000 -0.332437869 1999 -0.31103928 1998 -0.441741092 1997 -0.569094786 1996 -0.404820425 1995 -0.379711004 1994 -0.202858948 1993 -0.084509727 1992 -1.160923612 1991 -0.777464858 1990 -0.077701649 1989 -0.19663006 1988 -0.748404814 1987 -0.0053503 1986 -0.883840181 1985 -0.118907029 1984 0.012032097 1983 0.246430766 1982 -0.188639831 1981 -0.412326982 1980 0.609515423 1979 -1.118573351