Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences
RESEARCH ARTICLE

Dynamics of bacterial respiration and related growth efficiency, dissolved nutrients and dissolved oxygen concentration in a subarctic coastal embayment

Choon Weng Lee, I. Kudo, T. Yokokawa, M. Yanada and Y. Maita

Marine and Freshwater Research 53(1) 1 - 7
Published: 25 January 2002

Abstract

Temporal variations in dissolved oxygen, nutrient concentrations and oxygen utilization rates (<0.7 m fraction) were recorded for almost two years in the subarctic Funka Bay, Japan. Dissolved inorganic nitrogen ranged from 0 to 26 M, phosphate from 0 to 2 M and silicate from 1 to 64 M. There was evidence of nitrogen limitation. Dissolved oxygen concentration ranged from 130 to 440 M, and decreased to <150 M in the bottom layer in summer. The rate of oxygen utilization, attributed to bacterial respiration, ranged from 0.6 to 9.3 M day–1 at 10 m depth, and from 0.8 to 5.0 M day–1 at 90 m depth, and was the principal mechanism causing the decrease in dissolved oxygen in the bottom layer in the summer. Bacterial growth efficiencies calculated for the 10 m and 90 m depths were similar: 1.6–17.2% and 1.4–23.6%, respectively. With the bacterial growth efficiencies <25%, the bacteria in Funka Bay acted as a net sink of carbon, where >75% of the organic matter flux through bacteria could be mineralized to CO2.

http://dx.doi.org/10.1071/MF01003

© CSIRO 2002


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