Abstract
We measured O2 consumption and CO2 production by benthic respiration to examine the characteristics of organic matter metabolism in tidal flat sediments (A-C) of three different types in the northern part of Hiroshima Bay.
Benthic respirations were in the range of 0.196-4.07g-O2·m-2·d-1 (0.046-1.98g-C·m-2·d-1), 0.620-5.60g-02·m-2·d-1 (0.247-2.08g-C·m-2·d-1), 0.3l9-2.23g-02·m-2·d-1 (0.105-0.804g-C·m-2·d-1) in A, B and C, respectively.
Each tidal flat showed the highest respiration activity at high temperature in summer season, and almost same activity at same temperature in spite of different season, organic matter content and bacterial number in the sediment. From these results, it's considered to be temperature that has a most important effect on the benthic respiration activity in tidal flat. We examined temperature coefficient for the respiration by changing temperature into 5 stages of 5-40°C, and obtained Q10=2.75 and 2.39 in Band C, respectively.
Though the benthic respiration quatient (RQ) showed variations, the values yielded an annual total RQ of 1.04 in these three tidal sediments. We also estimated the ratios of macrobenthos respiration measured directly in the laboratory to total benthic respiration of tidal flats, and got the value of 3.4-100%, 14-65% and 3.7-40% in each tidal flat A, B and C.
