Net release of dissolved organic matter by the scleractinian coral Acropora pulchra |
| |
Authors: | Yasuaki Tanaka Toshihiro Miyajima Yu Umezawa Takeshi Hayashibara Hiroshi Ogawa Isao Koike |
| |
Institution: | aMarine Biogeochemistry Laboratory, Ocean Research Institute, The University of Tokyo, Minamidai 1-15-1, Nakano-ku, Tokyo, 164-0014, Japan;bNagasaki University, Bunkyo 1-14, Nagasaki-city, Nagasaki, 852-8521, Japan;cNational Research Institute of Far Seas Fisheries, Fisheries Research Agency, Fukuura 2-12-4, Kanazawa-ku, Yokohama-city, Kanagawa, 236-8648, Japan;dUniversity of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan |
| |
Abstract: | The net production of dissolved organic matter (DOM) and dissolved combined and free amino acids (DCAA and DFAA, respectively) by the hermatypic coral Acropora pulchra was measured in the submerged condition, and the production rates were normalized to the coral surface area, tissue biomass, and net photosynthetic rates by zooxanthellae. When normalized to the unit surface area, the production rates of dissolved organic carbon and nitrogen (DOC and DON, respectively) were 37 and 4.4 nmol cm− 2 h− 1, respectively. Comparing with the photosynthetic rate by zooxanthellae, which was measured by 13C-tracer accumulation in the soft tissue of the coral colony, the release rate of DOC corresponded to 5.4% of the daily net photosynthetic production. The tissue biomass of the coral colony was 178 µmol C cm− 2 and 23 µmol N cm− 2, indicating that the release of DOC and DON accounted for 0.021% h− 1 and 0.019% h− 1 of the tissue C and N, respectively. The C:N ratios of the released DOM (average 8.4) were not significantly different from those of the soft tissue of the coral colonies (average 7.7). While DFAA did almost not accumulate in the incubated seawater, DCAA was considerably released by the coral colonies at the rate of 2.1 nmol cm− 2 h− 1 on average. Calculating C and N contents of the hydrolyzable DCAA, it was revealed that about 20% and 50%–60% of the released bulk DOC and DON, respectively, were composed of DCAA. |
| |
Keywords: | Coral reefs Corals Dissolved amino acids Dissolved organic matter Zooxanthellae |
本文献已被 ScienceDirect 等数据库收录! |
|