风浪对枸杞岛铜藻(Sargassum horneri)分布格局的影响

Effects of wind wave on distribution pattern of Sargassum horneri around Gouqi Island

通过潜水调查枸杞岛铜藻的分布特征,并统计西北太平洋近65年台风生成的波浪对枸杞岛产生的影响以及近3年枸杞岛日常风力和风向的变化规律,分析了枸杞岛铜藻分布格局与风浪影响之间的关系。结果表明：铜藻主要分布在枸杞岛西北侧沿岸,且集中分布在平均海平面以下1~4 m较浅的水深范围内,而枸杞岛东到南侧则无铜藻分布,这与85.1%台风生成的波浪影响枸杞岛的东到南侧有关;近年来枸杞岛铜藻数量减少,但近年来台风生成的波浪对枸杞岛产生的影响并没有显著增强,说明铜藻数量的减少并不是由于近年来台风的显著增强而引起;虽然枸杞岛日常风力以西北-北向最强,西北-北向风向的发生频次也较多,但铜藻却集中分布在枸杞岛西北侧沿岸,说明枸杞岛西北侧大面积贻贝养殖筏可能对风浪的影响起到一定缓解作用,保护了近岸岩礁区铜藻的分布与生长。因此,在铜藻垂直分布上移的趋势下,风浪的影响加剧了对铜藻的破坏作用,风浪对枸杞岛铜藻的分布格局起到重要作用。

The distribution of Sargassum horneri around Gouqi Island was investigated by diving in May 2015. Typhoon data over the last 65 years in the northwestern Pacific and wind data over the last 3 years around Gouqi Island were collected,and the effect of wind wave on the distribution of S. horneri was analyzed. The results showed that S. horneri was abundant in northwestern coast,especially at 1 to 4 m water depth,while no S. horneri was observed in eastern and southern coasts,presumably due to wind wave caused by 85.1% typhoon. Recently the abundance of S. horneri around Gouqi Island decreased,but there was no evidence to deduce this change resulting from the increased typhoon frequency. North and northwest winds were strong and occurred more often around Gouqi Island,yet S. horneri gathered in the northwestern coast,probably because of the large amount of mussel culture rafts which might relieve the negative impact of wind wave and protect S. horneri. In conclusion,wind wave had an important effect on the distribution of S. horneri around Gouqi Island.