A comparative study on deep sublittoral marine algal floras between the Boso Peninsula and Ogasawara Islands, Japan

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K06830
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45030:Biodiversity and systematics-related
• Research Institution: National Museum of Nature and Science, Tokyo
• Principal Investigator: Kitayama Taiju 独立行政法人国立科学博物館, 植物研究部, 研究主幹 (20270407)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 小笠原 / 海藻相 / 植物地理学 / 藻類

Outline of Final Research Achievements

In order to uncover the peculiarity of the marine algal flora of Ogasawara Islands, Japan, investigations of mesophotic zones were carried out in both Chichijima Island, Ogasawara Islands and Ohara, the Boso Peninsula, resulted in collection of ca. 20 species respectively. Most of the species from Ohara are typically distributed in the Pacific coasts of Japan, though most of the mesophotic algal species has no record from the Japanese Archipelago, including a mesophotic green alga, Codium arenicola. In addition, a brown alga, Stypopodium cf. flabelliforme was collected from a shallow water of Chichijima Island. These suggested that marine algal flora of Ogasawara Islands is isolated from the ones of the Japanese Archipelago; the establishment of a new geographical district is required for the marine algal flora of Ogasawara Islands.

Free Research Field

海藻学

Academic Significance and Societal Importance of the Research Achievements

小笠原諸島の海藻相を浅所のみならず深所で調査し、日本列島側と比較することにより海藻の植物地理学的な進展に貢献した。従来海流と関連付けて議論されてきた日本海藻相区分において南西諸島とともに第III区に分類されていた小笠原の海藻相が日本列島の5つの区のいずれにも収まらず、第VI区の新設が必要であるほど異なることが解明された。世界自然遺産にも登録されている小笠原諸島のさらなる保全にも新たな意義をもたらすものと思われる。