Influence of sunshine duration and solar radiation on seaweed forest formation

2014 Fiscal Year Final Research Report

• Project/Area Number: 24580261
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: General fisheries
• Research Institution: Tokyo University of Marine Science and Technology
• Principal Investigator: ARAKAWA Hisayuki 東京海洋大学, 海洋科学技術研究科, 教授 (40242325)
• Co-Investigator(Kenkyū-buntansha): KOBASHI Humiaki 東京海洋大学, 大学院海洋科学技術研究科, 准教授 (80377077) ; SUZUKI Hidekazu 東京海洋大学, 大学院海洋科学技術研究科, 准教授 (90432062)
• Research Collaborator: KIMOTO Takumi 東京都島嶼農林水産総合センター
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 日照時間 / 海藻群落 / 日本沿岸 / 伊豆諸島 / 海中照度 / 日射量 / テングサ

Outline of Final Research Achievements

This research examined three points based on long-term climatic data: (1) How have total annual sunshine hours changed in certain areas in recent years? (2) How has light intensity under the ocean surface changed with respect to the sunshine? (3) What potential influences have affected seaweed forests because of the change?
Total sunshine hours in 2004 decreased in many regions of Japan (e.g., Sea of Japan coast, Izu Islands) compared with totals 30 years prior (1974). However, the amount of solar radiation increased. The vertical distribution of the agar weed community in the Miyake-jima region southeast of Japan’s main island of Honshu is densest at 20-m water depth. The decline in the agar weed catch did not correspond to the long-term change in sunshine hours but did correspond to the increased solar radiation.

Free Research Field

海洋環境光学