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Microbial respiration in the euphotic zone at Station ALOHA
Author(s) -
MartínezGarcía Sandra,
Karl David M.
Publication year - 2015
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10072
Subject(s) - photic zone , aloha , respiration , photosynthesis , oxygen , carbon cycle , environmental science , zoology , atmospheric sciences , chemistry , botany , ecology , biology , phytoplankton , geology , ecosystem , nutrient , telecommunications , organic chemistry , computer science , throughput , wireless
Measurements of the temporal and vertical variability of microbial community respiration (MCR) in the euphotic zone (0–200 m) at Station ALOHA were made using the in vivo INT method to constrain oxygen and carbon cycling at this oceanic site. Mean ( ± 1 SE) MCR was higher in the upper (0–100 m) (0.89 ± 0.05 mmol O 2 m −3 d −1 ) than in the lower (100–200 m) portion of the euphotic zone (0.52 ± 0.05 mmol O 2 m −3 d −1 ). Respiration in the 0.8 μm size‐fraction relative to respiration in the 0.2–0.8 μm size‐fraction was on average 1.4 ± 0.1. Variability in MCR was observed on both daily and monthly time scales, suggesting that respiration is a dynamic process throughout the year at Station ALOHA. MCR in the 0.2–0.8 μm size fraction was more variable than > 0.8 μm MCR. Despite significant vertical and temporal variability in MCR, the euphotic zone depth‐integrated (0–200 m) MCR was relatively constant (134.8 ± 11.8 mmol O 2 m −2 d −1 ) throughout the period of observation. Oxygen consumption via MCR always exceeded O 2 production extrapolated from 14 C‐primary production estimation, assuming a photosynthetic quotient of 1.13 mol O 2 produced : mol CO 2 fixed. MCR plus particulate carbon export from the euphotic zone for the period November 2011–October 2012 at Station ALOHA can be used to set a lower limit of ∼ 45 mol C m −2 yr −1 for gross primary production.