TY - JOUR
T1 - Subboreal aridity and scytonemin in the Holocene Black Sea
AU - Fulton, James M.
AU - Arthur, Michael A.
AU - Freeman, Katherine H.
N1 - Funding Information:
The authors are grateful to F. Garcia-Pichel for providing cryptobiotic soil samples and microbial mats from Guerrero Negro. We also acknowledge the laboratory assistance of G. Elsworth and S. Hunter and technical advice from D. Walizer. Three anonymous reviewers provided helpful comments that improved the manuscript. Funding was provided by the U.S. National Science Foundation (NSF EAR-0525464) to M.A. and K.F., and the Biogeochemical Research Initiative for Education (NSF DGE-9972759) provided graduate support for J.F. The Penn State Astrobiology Research Center provided additional funding to J.F. for developing scytonemin C and N isotope methods.
PY - 2012/8
Y1 - 2012/8
N2 - Many species of cyanobacteria tolerate exposure to harmful levels of ultraviolet (UV) radiation by producing photoprotective pigments. Scytonemin, found in extracellular polysaccharide sheaths, is produced in abundance when terrestrial or benthic cyanobacteria are exposed to direct sunlight, such as in desert soil crusts and intertidal mats. It is exclusive to cyanobacteria and therefore can serve as a diagnostic biomarker, particularly for UV-exposure growth conditions. Here we report that it is preserved in abundance in mid-Holocene sedimentary intervals in the Black Sea, a novel deep sea occurrence that demonstrates that scytonemin is resistant to degradation during erosion and transport. C and N isotopic compositions support the interpretation that scytonemin was derived from cyanobacteria in cryptobiotic desert soil, suggestive of expanding aridity during the Subboreal Phase in the Black Sea region. Scytonemin has potential for preservation in black shales, where it may serve as an important biomarker for tracing the evolution and expansion of cyanobacterial populations, especially in association with elevated UV stress.
AB - Many species of cyanobacteria tolerate exposure to harmful levels of ultraviolet (UV) radiation by producing photoprotective pigments. Scytonemin, found in extracellular polysaccharide sheaths, is produced in abundance when terrestrial or benthic cyanobacteria are exposed to direct sunlight, such as in desert soil crusts and intertidal mats. It is exclusive to cyanobacteria and therefore can serve as a diagnostic biomarker, particularly for UV-exposure growth conditions. Here we report that it is preserved in abundance in mid-Holocene sedimentary intervals in the Black Sea, a novel deep sea occurrence that demonstrates that scytonemin is resistant to degradation during erosion and transport. C and N isotopic compositions support the interpretation that scytonemin was derived from cyanobacteria in cryptobiotic desert soil, suggestive of expanding aridity during the Subboreal Phase in the Black Sea region. Scytonemin has potential for preservation in black shales, where it may serve as an important biomarker for tracing the evolution and expansion of cyanobacterial populations, especially in association with elevated UV stress.
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U2 - 10.1016/j.orggeochem.2012.05.008
DO - 10.1016/j.orggeochem.2012.05.008
M3 - Article
AN - SCOPUS:84862225831
VL - 49
SP - 47
EP - 55
JO - Organic Geochemistry
JF - Organic Geochemistry
SN - 0146-6380
ER -