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Title Transcription
ナカウミ コシンブ ニオケル コテイ ノ スイチュウ エイゾウ ソノ2 : トウキ ノ キセツフウ ニ タイスル テイソウスイ ノ ドウタイ
Title Alternative
Pictures of bottom surface in the central part of Lake Nakaumi (part 2) : dynamics of bottom water with regard to a seasonal wind in winter
File
language
jpn
Author
Nomura, Ritsuo
Description
We observed the bottom water movements and the ecology of brackish organisms over a fi ve days of Feb. 13- Feb.17, 2007, by means of a long-term monitoring waterproof camera that installed on the bottom of Lake Nakaumi at a depth of 6.5 m. The winter organisms are occupied with a hydrozoan and cionid community. These organisms indicate the bottom water is enriched with dissolved oxygen and the condition is quite different from our fi rst report that showed a bacterial mat covering the bottom fl oor.
Unstable condition was occurred by a strong south and westerly wind over the speed of 10 m/s in Feb. 14 and 15. Winnowing of bottom sediments occurred at wind speeds greater than 10 m/s, which supports the previous observation. Water clarity decreased in these days. However, we confi rmed that the winter bottom sediment is easy to blown up even in the speed of ~7 m/s, which is supposedly due to the absence of bacterial mat. In contrast to the quick response of bottom turbulence to wind stress, waters of bottom and the upper waters were not easily mixed, despite of the wind speed of over 15 m/s. A mixing of the bottom and the upper waters was temporally occurred after the 20 hours continuous blow over 11~16 m/s, but soon after that the waters from different depths were separated while the strong wind continuing.
A number of fi shes along with a school of unknown fry were frequently observed when the bottom water turbulence stopped. We are able to recognize the rich fi sh communities in this season.
Subject
wind speed
bottom turbulence
winnowing
sediment
water dynamics
Journal Title
Laguna : 汽水域研究
Volume
15
Start Page
57
End Page
67
ISSN
21852995
Published Date
2008-12
NCID
AN10439529
Publisher
島根大学汽水域研究センター
NII Type
Departmental Bulletin Paper
Format
PDF
Text Version
出版社版
OAI-PMH Set
Estuary Research Center
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