Distinctive copepod community of the estuarine turbidity maximum: comparative observations in three macrotidal estuaries (Chikugo, Midori, and Kuma Rivers), southwestern Japan

作者：Suzuki Keita W^*; Nakayama Kouji; Tanaka Masaru

来源：Journal of Oceanography, 2013, 69(1): 15-33.

DOI：10.1007/s10872-012-0151-7

• Ariake Sea
• Chikugo River
• Community ecology
• Copepod
• Estuarine turbidity maximum
• Kuma River
• Midori River
• Salinity
• Sinocalanus sinensis
• Turbidity

Copepods are considered to be a vital component connecting the unique macrotidal environment to the high productivity and high biodiversity of the Ariake Sea. To examine the spatiotemporal succession of copepod communities, we conducted monthly sampling (vertical hauls of a 100-mu m mesh plankton net) in three neighboring macrotidal estuaries between 2005 and 2006. Irrespective of the season, three copepod communities were recognized in relation to the relatively long gradients of salinity and turbidity along the Chikugo and Midori River estuaries. The oligohaline community (salinity 1-10) was observed at higher turbidities (%26gt; 100 NTU), whereas the freshwater (salinity %26lt; 1) and meso/polyhaline (salinity %26gt; 10) communities were associated with lower turbidities (%26lt; 100 NTU). The oligohaline calanoid Sinocalanus sinensis occurred only in the Chikugo River estuary, maintaining a large biomass (dry weight %26gt; 10 mg m(-3)) in or close to the well-developed estuarine turbidity maximum (ETM) throughout the year. In the Midori River estuary, the oligohaline community lacked S. sinensis and showed a minimum biomass during winter (%26lt; 10 mg m(-3)). In both estuaries, the freshwater community always remained at a small biomass (%26lt; 1 mg m(-3)), whereas the meso/polyhaline community showed marked seasonal changes in biomass (0.1-657 mg m(-3)). The prevalence of higher salinities allowed only the meso/polyhaline community to occur in the Kuma River estuary. In summary, S. sinensis characterized the copepod community distinctive of the well-developed ETM, potentially serving as an important link to higher trophic levels during winter when copepods are scarce in other areas.

• 出版日期2013-2