摘要
对海南岛鹿回头小东海和三亚湾珊瑚礁区底质中的样品进行分析研究,共获得有孔虫40属90种,其中包括3新种4未定种.小东海有孔虫壳体一般较坚固,大有孔虫占绝对优势;三亚湾有孔虫壳体易破碎,大有孔虫相对贫乏.水动力状况及盐度差异是造成两地有孔虫不同的主要原因.磨蚀试验表明,有孔虫壳体形态结构与环境有密切的关系.
The samples were collected from Luhuitou Peninsula located at the southernmost end of Hainan Island, consisting of 90 species in 40 genera, including 3 new species, Textularia sanyaensis, T.longiflata and Triloculina delicata, and 4 undeterminable species, all of which are similar to those of the Xisha Islands.
It is very interesting that foraminifera in Xiaodonghai Bay differ significantly from those in Sanya Bay.
1. The number of foraminifera in one gram of dry sample is 70 in Xiaodonghai Bay, but only 26 in Sanya Bay.
2. Larger foraminifera are abundant in Xiaodonghai Bay, Such as Amphistegina madagascariensis d'Orbigny, A. radiata (Fichtel et Moll), alcarina hainanensis Li, C. spengleri (Gmelin) and Operculina ammonoides (Gronovius), but rare in Sanya Bay except Calcarina hainanensis Li.
3. Calcarina spengleri (Gmelin) and Elphidium craticulatum (Fichtel et Moll) are common in Xiaodonghai Bay, but have not been found in Sanya Bay.
4. In Xiaodonghai Bay, the porcellaneous smaller foraminifera are dominated by Quinqueloculina spp. which are relatively big, with thick test wall and well-developed ornamentation, while in Sanya Bay, they are dominated by Triloculina spp. which are small, with thin test wall and poor ornamentation.
Since Xiaodonghai Bay and Sanya Bay are close in neighbourhood, how can such differences be explained?
Firstly, Luhuitou is under the influence of tropical monsoon which is dominated by northeast wind in winter and south wind in summer. Xiaodonghai Bay faces the monsoon, and thus has become a high energy habitat with well agitated water and abundant food, while Sanya Bay is on the lee side. Secondly, the salinity of Sanya Bay is lower, due to the influence of brackish water from Sanya Lagoon and from alongshore current of Beibu Gulf. These two main factors result in the foraminiferal differences.
The foraminifera in Xaidonghai Bay are doiminated by the five larger species with strong tests to survive in the high energy habitat. From abrasion test it has been found that Calcarina spengleri (Gmelin) and Amphistegina madagascariensis d'Orbigny are the two strongest species; the former has large nodules and spines on the surface, and the latter has thick walls and a large number of tightly connected small chambers. It has also been found that Calcarina hainanensis Li has stronger tests in Xiaodonghai Bay than in Sanya Bay. Test strength appears to be closely associated with external physical environment. Generally, foraminiferal tests are stronger in high energy habitat than in low one.
出处
《古生物学报》
CAS
CSCD
北大核心
1993年第6期673-684,795-798,共12页
Acta Palaeontologica Sinica
关键词
有孔虫
全新世
古动物学
Foraminifera
Holocene
Hainan Island
