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Influence of isotope fractionation on the nitrogen isotope composition of the brown macroalga Undaria pinnatifida
Author(s) -
Endo Hikaru,
Fukuda Hideki,
Takahashi Daisuke,
Okumura Yutaka,
Inomata Eri,
Ito Kinuko,
Yoshimizu Chikage,
Tayasu Ichiro,
Nagata Toshi
Publication year - 2018
Publication title -
phycological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.438
H-Index - 44
eISSN - 1440-1835
pISSN - 1322-0829
DOI - 10.1111/pre.12332
Subject(s) - thallus , fractionation , bay , isotopes of nitrogen , isotope , biology , δ15n , nitrogen , seawater , isotope fractionation , isotope analysis , algae , botany , stable isotope ratio , environmental chemistry , δ13c , ecology , oceanography , chemistry , geology , physics , organic chemistry , quantum mechanics
SUMMARY Although the stable nitrogen isotope ratio ( δ 15 N value) of macroalgae is used to indicate sources of dissolved inorganic nitrogen in coastal marine environments, little is known about the effects of isotope fractionation on the δ 15 N value. We compared the δ 15 N values of Undaria pinnatifida cultivated at an inner bay and an exposed site (sites A and B, respectively) in Shizugawa Bay on the northeastern Pacific coast of Japan. Values for algal growth indicators, including thallus length, area, and weight, were higher at site B than at site A. The δ 15 N value of U. pinnatifida was significantly lower at site B (4.7 ± 1.0‰; mean ± standard deviation) than at site A (6.7 ± 0.4‰). This difference in the δ 15 N value of U. pinnatifida could not be explained by the δ 15 N value of seawater NO 3 (source isotopic signature), which was similar at the two sites (7.5 ± 0.3‰). The pooled data from the two sites indicated that the δ 15 N value of U. pinnatifida decreased with increasing thallus size. The results suggest that the δ 15 N value of U. pinnatifida is influenced by isotope fractionation.