# 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_1_19_Mg_Ca.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: Aasiaat # Location: Ocean>Atlantic Ocean>North Atlantic Ocean # Northernmost_Latitude: 68.7361 # Southernmost_Latitude: 68.7361 # Easternmost_Longitude: -52.53635 # Westernmost_Longitude: -52.53635 # Elevation: #------------------ # Data_Collection # Collection_Name: 16_1_19 # 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 0.081813796 2014 1.517954357 2013 -0.597927079 2012 0.518921178 2011 -0.561154965 2010 0.066479699 2009 -0.412049758 2008 -0.850251415 2007 -0.046946467 2006 -0.6241173 2005 0.904733571 2004 1.220172407 2003 1.316371932 2002 0.831882714 2001 -0.860683592 2000 0.288686531 1999 0.732935721 1998 0.707379226 1997 -0.254994325 1996 -0.088850074 1995 -0.14871888 1994 0.116342506 1993 -1.099847822 1992 -0.711485242 1991 -0.304289174 1990 -0.01513627 1989 -0.416725378 1988 0.558102023 1987 0.397958935 1986 -0.897094864 1985 0.141155681 1984 0.013918432 1983 -0.074628881 1982 -0.42353538 1981 -0.654315348 1980 0.701149322 1979 -1.073205817