# Gulf of Maine bulk and amino acid nitrogen isotope data from 1783-2010 #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # Template Version 3.0 # Encoding: UTF-8 # NOTE: Please cite original publication, online resource and date accessed when using this data. # If there is no publication information, please cite Investigator, title, online resource and date accessed. # # Description/Documentation lines begin with # # Data lines have no # # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/29292 # Description: NOAA Landing Page # Online_Resource: https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/whitney2019/whitney2019-fig5.txt # Description: NOAA location of the template # # Data_Type: Paleoceanography # # Dataset_DOI: # # Parameter_Keywords: nitrogen isotopes #--------------------------------------- # Contribution_Date # Date: 2020-03-20 #--------------------------------------- # File_Last_Modified_Date # Date: 2020-03-20 #--------------------------------------- # Title # Study_Name: Gulf of Maine bulk and amino acid nitrogen isotope data from 1783-2010 CE #--------------------------------------- # Investigators # Investigators: Whitney, Nina M.; Johnson, Beverly J.; Dostie, Philip T.; Luzier, Katherine; Wanamaker Jr., Alan D. #--------------------------------------- # Description_Notes_and_Keywords # Description: 2 sigma combined uncertainty (analytical uncertainty and average correction factor) for bulk d15N is +/- 0.36 per mil and for d13C is +/- 0.22 per mil. The long term, average 2 sigma analytical uncertainty for d15N of amino acids is +/- 1.9 per mil. The 2 sigma propagated analytical uncertainty for the trophic position calculation is +/- 0.5. Details of the construction of the chronology used for this study can be found in Wanamaker et al., 2019 (https://doi.org/10.1007/s00382-018-4513-8). Core water depths range from -38 to -80 meters. # Provided Keywords: geochemistry, Arctica islandica, nitrogen isotopes, compound specific isotopic analyses of amino acids, Gulf of Maine, ocean circulation #--------------------------------------- # Publication # Authors: Whitney, Nina M., Johnson, Beverly J., Dostie, Philip T., Luzier, Katherine, Wanamaker Jr., Alan D. # Published_Date_or_Year: 2019 # Published_Title: Paired bulk organic and individual amino acid d15N analyses of bivalve shell periostracum: A paleoceanographic proxy for water source variability and nitrogen cycling processes # Journal_Name: Geochimica et Cosmochimica Acta # Volume: 254 # Edition: # Issue: # Pages: 67-85 # Report_Number: # DOI: 10.1016/j.gca.2019.03.019 # Online_Resource: # Full_Citation: # Abstract: Developing high resolution, well-dated marine proxies of environmental, climatic, and oceanographic conditions is critical in order to advance our understanding of the ocean's role in the global climate system. While some work has investigated bulk and compound specific stable nitrogen isotopes (d15N) in bivalve shells as proxies for environmental variability, the small concentrations of nitrogen found in the organic matrix of the shell calcium carbonate (CaCO3) makes developing high resolution records challenging. This study investigates the potential of using the bulk and amino acid d15N of bivalve periostracum, the protein layer on the outside of the shell, as a proxy archive of nitrogen cycling processes and water source variability. Bulk d15N values were measured on the periostracum, aragonitic CaCO3, and adductor muscle of Arctica islandica shells collected in the Gulf of Maine. Increased variability of isotopic values across growth lines compared to along growth lines support mechanistic reasoning based on growth processes that periostracum is recording changes in d15N over the course of the clam's lifetime (up to 500 years). In addition, the statistically significant relationship between periostracum d15N and contemporaneous carbonate d15N of the same shell (r= 0.82, p<.0001, n=40) suggests that periostracum preserves a similar d15N signal to that preserved in the carbonate. This finding, coupled with the fact that source amino acid d15N values of periostracum are similar to that of the adductor muscle and the particulate organic matter (POM) consumed by the clam, suggests that periostracum bulk d15N reflect the d15N of the clam's food source. The isotopic offsets between periostracum, carbonate, and adductor muscle d15N values are primarily caused by differences in amino acid composition of the different tissue types, as evidenced by isotope mass balance calculations, although may also be related to differences in d15N values of the individual amino acids of the different tissue types, especially the trophic amino acids. Compound specific d15N analyses of the periostracum of A. islandica shells were used to determine that the calculated trophic position of the clams in this study (1.4 +/- 0.4) did not change significantly between 1783 and 1997. Phenylalanine d15N values over the last 70 years show similar trends to that of the bulk record, suggesting that changes in bulk d15N of that time period are related to changes in baseline d15N. Periostracum d15N values from shells collected in the western Gulf of Maine have decreased by ~1‰ since the mid-1920s. This trend (-0.008‰/year) is not statistically different from the trend of previously published d15N values of deep-sea corals from the entrance to the Gulf of Maine over the same time period. This coral record has been shown to indicate a shift in water mass source to the region and therefore the similarity between the two records suggest that changes in periostracum d15N values are reflecting broader North Atlantic hydrographic changes. Our study introduces a new, high-resolution and absolutely dated paleoceanographic proxy of baseline d15N, presenting the opportunity for future reconstructions of aspects of nitrogen cycling and water source changes in the global oceans. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: National Science Foundation # Grant: OCE1003438, OCE0929900 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Geological Society of America # Grant: 2016 Gretchen L. Blechschmidt award #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Iowa State University Department of Geological and Atmospheric Sciences # Grant: Bruce Bowen Fellowship #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Bates College # Grant: #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Maine Technology Institute # Grant: Maine Marine Research Fund #--------------------------------------- # Site_Information # Site_Name: Seguin Is.,Jonesport,Cobscook Bay,Isle au Haut,Damariscotta Est,Darling MC # Location: Gulf of Maine # Country: United States # Northernmost_Latitude: 44.9 # Southernmost_Latitude: 43.7 # Easternmost_Longitude: -67.1 # Westernmost_Longitude: -69.7 # Elevation: #--------------------------------------- # Data_Collection # Collection_Name: Gulf of Maine Fig5 Whitney2019 # First_Year: 1926 # Last_Year: 2002 # Time_Unit: AD # Core_Length: # Notes: #--------------------------------------- # Chronology_Information # Chronology: #--------------------------------------- # Variables # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) ## year age,,,year Common Era,,paleoceanography,,,N,average age ## beginning_year age at sample start,,,year Common Era,,paleoceanography,,,N,age start of sampling ## end_year age at sample end,,,year Common Era,,paleoceanography,,,N,age end of sampling ## bulk_d15N delta 15N,bivalve,,per mil Air,,paleoceanography,,isotope ratio mass spectrometry,N,Arctica islandica periostracum; bulk d15N ## phenylalanine_d15N delta 15N,bivalve,,per mil Air,,paleoceanography,,isotope ratio mass spectrometry,N,compound specific isotope analysis of amino acids; d15N of phenylalanine; Arctica islandica periostracum #------------------------ # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing_Values: -999 year beginning_year end_year bulk_d15N phenylalanine_d15N 1926 1926 1927 4.9304224 -999 1927 -999 -999 -999 -999 1928 -999 -999 -999 -999 1929 -999 -999 -999 -999 1930 -999 -999 -999 -999 1931 1930 1932 3.6262936 -999 1932 -999 -999 -999 -999 1933 1933 1933 4.6014526 -999 1934 1934 1934 5.7265198 -999 1935 1935 1935 4.3710256 -999 1935.5 1932.5 1938.5 5.16624 -999 1936 1936 1936 4.6393538 -999 1937 -999 -999 -999 -999 1938 -999 -999 -999 -999 1938.5 1938 1939 4.4992576 -999 1939 -999 -999 -999 -999 1940 1940 1940 4.5316346 -999 1941 -999 -999 -999 -999 1942 1940 1945 4.7087072 -999 1943 -999 -999 -999 -999 1944 -999 -999 -999 -999 1945 -999 -999 -999 -999 1946 1944 1948 4.41 -999 1946.25 1939.25 1953.25 4.796388 -999 1946.5 1939.5 1953.5 4.8903504 -999 1947 -999 -999 -999 -999 1948 1945.5 1950.5 3.3846256 -999 1948.5 1948.5 1948.5 4.7061944 -999 1949 -999 -999 -999 -999 1949.5 1949 1950 4.285946 -999 1950 -999 -999 -999 5.6007 1951 1951 1951 5.2278198 -999 1951.5 1951.5 1951.5 4.98 -999 1952 1952 1952 5.8073092 -999 1952.5 1952.5 1952.5 4.036148 -999 1953 -999 -999 -999 -999 1953.5 1953 1954 4.4887464 -999 1954 -999 -999 -999 -999 1954.5 1954 1955 5.2437782 5.9513 1955 -999 -999 -999 -999 1955.5 1955 1956 4.846813 -999 1956 -999 -999 -999 -999 1956.25 1956.25 1956.25 3.9352492 -999 1956.5 1953.5 1959.5 4.1910418 -999 1957 -999 -999 -999 -999 1957.5 1957 1958 4.6905208 -999 1958 -999 -999 -999 -999 1958.5 1958 1959 5.1849316 -999 1959 -999 -999 -999 -999 1959.5 1959 1960 4.9126414 -999 1960 -999 -999 -999 4.2376 1960.5 1956.5 1964.5 4.4575236 -999 1961 1959 1963 4.5416086 -999 1962 -999 -999 -999 -999 1963 1963 1963 4.5426012 -999 1964 1964 1964 3.3925508 -999 1965 1964 1966 4.917788 -999 1966 -999 -999 -999 -999 1967 -999 -999 -999 -999 1968 -999 -999 -999 -999 1969 -999 -999 -999 -999 1970 1967 1973 4.4381008 -999 1971 -999 -999 -999 -999 1972 1968.5 1975.5 4.5254964 -999 1973 -999 -999 -999 -999 1974 -999 -999 -999 -999 1975 -999 -999 -999 -999 1976 -999 -999 -999 -999 1977 1975 1979 4.133672 -999 1978 -999 -999 -999 -999 1979 -999 -999 -999 -999 1980 1978.5 1981.5 4.3084768 -999 1981 1979 1983 3.7763156 -999 1982 -999 -999 -999 -999 1983 1978.5 1987.5 4.2256164 -999 1984 1983 1985 4.6284552 5.0699 1984.5 1984 1985 5.0924088 -999 1985 -999 -999 -999 -999 1985.5 1985 1986 4.506504 -999 1986 -999 -999 -999 -999 1987 -999 -999 -999 3.3849 1988 1987 1989 4.2124666 -999 1989 1988 1990 4.1776356 -999 1990 -999 -999 -999 -999 1991 -999 -999 -999 -999 1992 -999 -999 -999 -999 1993 -999 -999 -999 -999 1994 1990 1998 3.6305936 -999 1995 -999 -999 -999 -999 1996 -999 -999 -999 -999 1997 1992.5 2001.5 3.776796 4.554 1998 1995.5 2000.5 4.5820518 -999 1999 -999 -999 -999 -999 2000 -999 -999 -999 -999 2001 -999 -999 -999 -999 2002 1999 2005 4.3268733 -999