Japan Geoscience Union Meeting 2015

Presentation information


Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS26] Biogeochemistry

Thu. May 28, 2015 11:00 AM - 12:45 PM 104 (1F)

Convener:*Muneoki Yoh(Tokyo University of Agriculture and Technology), Shibata, Hideaki(Field Science Center fot Northern Biosphere, Hokkaido University), Naohiko Ohkouchi(Japan Agency for Marine-Earth Science and Technology), Youhei Yamashita(Faculty of Environmental Earth Science, Hokkaido University), Chair:Yoshinori Takano(Japan Agency for Marine-Earth Science and Technology (JAMSTEC)), Seiya Nagao(Institute of Nature and Environmental Technology, Kanazawa University), Izumi Watanabe(Graduate School of Agriculture, Tokyo University of Agriculture and Technology), Yoriko Yokoo(同志社大学理工学部)

11:00 AM - 11:15 AM

[MIS26-08] Characterizing the biological and microbial community dynamics in the coastal sea surface microlayer

*Shu-kuan WONG1, Shotaro SUZUKI1, Yingshun CUI1, Ryo KANEKO1, Kazuhiro KOGURE1, Koji HAMASAKI1 (1.Laboratory of Marine Microbiology, Atmosphere and Ocean Research Institute, The University of Tokyo)

Keywords:Surface microlayer, Microbial community structure, Biological enrichment

The sea surface microlayer is a thin surface film located at the interfacial point between the sea surface and the atmosphere. Compared to the underlying water (UW) below it, the SML is a unique but harsh environment; with elevated meteorological stresses and biologically and chemically enriched. Thus, it is widely recognized that the physical, chemical and biological processes in the SML are very different compared to UW even with just a few centimeters difference in depth. The proximity of this thin layer to the atmosphere also makes this layer highly dynamic and one of the most important layer to control the air-sea biogeochemical exchanges and climate-related processes. This biofilm-like thin layer with a depth of less than 1000 μm, this layer have found to exist in most aquatic habitat and oceanic environments. This layer was found to be composed of hydrated gelatinous layer entangled in a matrix of dissolved organic matter composed mainly of transparent exopolymer particles (TEP). While few research have shown that the bacterial community in the SML possessed different functional genes compared to the underlying water others, in mesocosm experiments, have shown that bacterioneuston responded differently when introduced to experimentally-induced carbon dioxide loading scenarios in mesocosm experiments. However, little is still known about the microbial structure in this layer and their contribution towards the global biogeochemical cycles. In our research, bacteria community structure in the SML (bacterioneuston) at Aburatsubo Inlet, Misaki during summer and winter were examined using high throughput sequencing. In contrast to conditions in UW that remained constant throughout the sampling period, SML was highly dynamic with fluctuations in biological matter concentrations and bacterial communities. At times when the SML was enriched with biological matter and distinct bacterioneuston communities were formed. When the SML was enriched, rare bacterial groups including those that could play a role in biogeochemical cycles were more abundantly found in the SML and the diversity of these groups increased in proportion to the magnitude of biological matter enrichment in the SML.