TY - JOUR
T1 - The 13 C method as a robust alternative to 14 C-based measurements of primary productivity in the Mediterranean Sea
AU - López-Sandoval, Daffne C.
AU - Delgado-Huertas, Antonio
AU - Agustí, Susana
N1 - Publisher Copyright:
© © The Author(s) 2018. Published by Oxford University Press.
PY - 2018/9/1
Y1 - 2018/9/1
N2 - Due to the increasing constraints on using the radioactive isotope 14 C to measure primary productivity (14 C-PP), we determined the surface carbon fixation rates in the Mediterranean Sea, using the alternative stable isotope 13 C method (13 C-PP). Rates obtained (13 C-POCp) were compared with simultaneous 14 C-POCp measurements in samples of different volumes (72 mL and 1.2 L). We also tested the variation of the percentage of dissolved primary production (PER), to the total productivity using organic and inorganic filters (14 C method). 13 C-POCp rates ranged from 0.4, in the Ionian basin, to 1.5 mgC m -3 h -1 in the Ligurian region. These results agreed with those found with the 14 C-PP in 1.2-L samples (two sample t-test, t = 1.035, df = 22, P = 0.31). However, we found that 14 C-POCp rates derived from 72-mL incubations were 46% lower than those measured with 13 C-PP. The discrepancy between large and small volume incubations was likely due to differences in the number of large phytoplankton cells within the community. PER values measured with silver membrane filters yielded similar results than those obtained using polycarbonate filters. Our findings showed that when the sample size is carefully chosen, the 13 C-PP provide comparable results to 14 C-PP even in waters of low productivity in the Mediterranean Sea.
AB - Due to the increasing constraints on using the radioactive isotope 14 C to measure primary productivity (14 C-PP), we determined the surface carbon fixation rates in the Mediterranean Sea, using the alternative stable isotope 13 C method (13 C-PP). Rates obtained (13 C-POCp) were compared with simultaneous 14 C-POCp measurements in samples of different volumes (72 mL and 1.2 L). We also tested the variation of the percentage of dissolved primary production (PER), to the total productivity using organic and inorganic filters (14 C method). 13 C-POCp rates ranged from 0.4, in the Ionian basin, to 1.5 mgC m -3 h -1 in the Ligurian region. These results agreed with those found with the 14 C-PP in 1.2-L samples (two sample t-test, t = 1.035, df = 22, P = 0.31). However, we found that 14 C-POCp rates derived from 72-mL incubations were 46% lower than those measured with 13 C-PP. The discrepancy between large and small volume incubations was likely due to differences in the number of large phytoplankton cells within the community. PER values measured with silver membrane filters yielded similar results than those obtained using polycarbonate filters. Our findings showed that when the sample size is carefully chosen, the 13 C-PP provide comparable results to 14 C-PP even in waters of low productivity in the Mediterranean Sea.
KW - 13 C
KW - 14 C
KW - Mediterranean Sea
KW - exudation
KW - primary productivity
UR - http://www.scopus.com/inward/record.url?scp=85054296880&partnerID=8YFLogxK
U2 - 10.1093/plankt/fby031
DO - 10.1093/plankt/fby031
M3 - Article
C2 - 30279616
AN - SCOPUS:85054296880
SN - 0142-7873
VL - 40
SP - 544
EP - 554
JO - Journal of Plankton Research
JF - Journal of Plankton Research
IS - 5
ER -