首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Phytoplankton growth and microzooplankton grazing in the Sea of Okhotsk during late summer of 2006
Authors:Hongbin Liu  Koji Suzuki  Jun Nishioka  Rumi Sohrin  Takeshi Nakatsuka
Institution:1. Department of Biology, Atmospheric, Marine and Coastal Environment (AMCE) Program, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong;2. Faculty of Environmental Earth Science, Hokkaido University, North 10 West 5, Kita-ku, Sapporo 060-0810, Japan;3. Institute of Low Temperature Science, Hokkaido University, North 19 West 8, Kita-ku, Sapporo 060-0810, Japan;4. Institute of Geosciences, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan
Abstract:The Sea of Okhotsk is one of the most productive marine basins in the world ocean and plays an important role in transport of organic carbon and iron to the western subarctic Pacific. We report the first measurements of phytoplankton growth and microzooplankton grazing rates in the Sea of Okhotsk, in late summer of 2006. The study area can be divided into two areas: nutrient-sufficient waters on the continental shelf along the east coast of Sakhalin Island and in the vicinity of Bussol Strait, and surface nutrient-depleted waters beyond the shelf break and in the vicinity of Sakhalin Bay. Phytoplankton growth rate in the studied area was strongly affected by nutrient availability, with high phytoplankton growth rate (0.55±0.14 d?1) in the nutrient-replete region and severely depressed growth (0.03±0.05 d?1) in the nutrient-depleted region. On the other hand, microzooplankton grazing rates in both the nutrient-replete and nutrient-depleted regions were approximately the same (0.26±0.20 d?1 vs. 0.27±0.24 d?1). Consequently, microzooplankton grazing consumed <50% of the phytoplankton growth in nutrient-rich waters but >3 times the phytoplankton growth in nutrient-depleted waters. Phytoplankton physiological condition as measured by the maximum photochemical quantum efficiency (Fv/Fm) of algal photosystem II (PS II) showed a general trend in agreement with the in situ growth rate of phytoplankton. In contrast to the phytoplankton community, picophytoplankton, especially the cyanobacteria Synechococcus, showed no nutrient effect on their growth, and the growth and mortality rates were well balanced, suggesting that they have a low nutrient requirement and their biomass was controlled principally by microzooplankton grazing.
Keywords:
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号