Skeletal growth of Dipsastraea speciosa (Dana, 1846) from the subtropical and temperate regions in Japan
| Autor: | NAGATA, Shunsuke, SUGIHARA, Kaoru, IRINO, Tomohisa, WATANABE, Tsuyoshi, YAMANO, Hiroya |
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| Jazyk: | japonština |
| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | 日本サンゴ礁学会誌. 15:37-56 |
| ISSN: | 1345-1421 |
| Popis: | 琉球列島の南西部に位置する沖縄県西表島（北緯 24°25′，東経 123°47′）と，九州の北西部に位置する長崎県福江島と若松島および壱岐と対馬（北緯 32°39′－34°24′，東経 128°39′－129°40′）から採集されたイシサンゴの一種であるキクメイシ Dipsastraea speciosa (Dana, 1846) [= Favia speciosa (Dana, 1846)]の群体骨格の成長パラメータ（伸長量，密度ならびに石灰化量）を測定し，それらの骨格成長と緯度変化に伴う年平均表層海水温との関連を考察した。その結果，亜熱帯域に位置する西表島産キクメイシの年平均密度と石灰化量は，温帯域に位置する長崎県産のそれらより有意に高かったが，伸長量については有意差が認められなかった。伸長量と石灰化量，密度と石灰化量の間には，調査地域全体でそれぞれ正の相関がみられたが，伸長量と密度の間には認められなかった。この結果は，キクメイシと同科に属する大西洋産 Orbicella (= Montastraea) や，キクメイシと同じく太平洋に生息するハマサンゴ属 Porites に関する先行研究結果よりも，大西洋に広く生息するハマサンゴ属の一種 Porites astreoides Lamarck, 1816 のものに類似していた。Porites astreoides とキクメイシは，それぞれに近縁な種・属に比べて地理的生息範囲が広く，伸長量と石灰化量が低いといった共通の特徴を持つ。日本産キクメイシでは，3 つの骨格成長パラメータの中で，石灰化量が年平均表層海水温と最も相関が高かった。このことから，少なくとも日本列島に生息するキクメイシは，年平均表層海水温の緯度勾配に合わせて骨格の伸長量や密度を変えながら，石灰化量を一定に保っている可能性がある Skeletal growth parameters (extension rate, density and calcification rate) were determined for annual growth bands in skeletal slabs and tips of the zoothanthellate scleractinian (hermatypic) coral Dipsastraea speciosa (Dana, 1846) [= Favia speciosa (Dana, 1846)] at Iriomote Island in the southwestern part of the Ryukyus (24°25′N, 123°47′E) and at Fukue, Wakamatsu, Iki and Tsushima islands in the northwestern part of Kyushu (32°39′N – 34°24′N, 128°39′E – 129°40′E), Japan. Relationships among these three parameters along a latitudinal gradient in annual mean sea surface temperatures (SSTs) were also examined. Annual mean density and calcification rate in D. speciosa of Iriomote Island located in a subtropical region (Iriomote Is.) were higher than those of the other islands in temperate regions, although there was no significant difference in the extension rates between the two regions. These results agreed well with those of Porites astreoides Lamarck, 1816 in the Atrantic rather than those of the Atlantic Orbicella (= Montastraea) and the Pacifc Porites species. Both Dipsastraea speciosa and Porites astreoides are geographically widespread species, and they have lower extension and calcification rates than other neighboring genera/species. Of the three growth parameters of D. speciosa, the calcification rate showed the highest significant correlation with the annual mean SSTs. It suggests that while D. speciosa distributed in the Japanese islands could keep their calcification rates stable for each site, they change their extension rates and densities in response to the latitudinal gradient in annual mean SSTs. |
| Databáze: | OpenAIRE |
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