Foraminiferal distribution and diversity, Madang Reef and Lagoon, Papua New Guinea
Foraminiferal distribution and diversity, Madang Reef and Lagoon, Papua New Guinea
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DOI：
10.1007/s00338-003-0298-1
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发表时间：
2003-07-01
期刊：
影响因子：
3.5
通讯作者：
Lipps, JH
中科院分区：
文献类型：
--
作者：
Langer, MR;Lipps, JH
在巴布亚新几内亚（PNG）北部海岸的Madang泻湖，有孔虫物种分布的数值q模式聚类分析定义了不同的有孔虫群，它们占据了四个主要的环境和沉积体制，通常与海岸平行：(1)港口和海湾入口，有大量的淡水径流和有机碎屑输入；(2)受悬垂红树林或淡水径流等海岸因素影响的环礁；(3)泻湖中央湖底深度超过50米，覆盖着细沙和从中升起的斑状珊瑚礁；(4)毗邻活珊瑚覆盖的礁前坡和砂质礁后坡的堡礁。这四个聚类在物种丰富度和Fisher α多样性分析中也得到了反映。聚类4包括79种大型、厚壳千脂类、强健的凝集类、calcarinids和amphisteginids (Fisher α大于或等于20)，它们出现在富含珊瑚的堡礁和后礁上。集群3有50个物种（Fisher alpha=8-20），占据泻湖中央。集群2有25种或更少的物种（Fisher alpha=2-6），发生在浅边缘珊瑚礁上。集群1的多样性最少（小于或等于7种，Fisher α小于或等于2种），并且发生在较大河流和小溪口的港口和海湾中。较大的、内共生的有孔虫（alveolinellids、sosolidids、amphisteginids、nummultiids和calcarinids）通常生活在礁后和礁前斜坡和泻湖中，避开富含有机物的沿海和港口栖息地，优先生活在泻湖底部光线充足的环境中。河口和海湾对于珊瑚礁系统来说是不寻常的，因为它们的有机物含量很高，这创造了低氧和富含营养的条件。这里的有孔虫动物群仅由少数占主导地位，而且大多数是特别薄壳和高度脆弱的物种。每个动物群都包含一些数量丰富的指示物种，这些物种在其他动物群中没有出现。这意味着珊瑚礁和泻湖复合体内的水平迁移率较低，并表明群群之间的动物混合是有限的。因此，有孔虫的死亡组合可能是原生的，并保留了有关原始群落结构的信息。它们还可以保存古生态学研究中有用的环境信息，是礁湖生境的良好生态指标。
In the Madang Lagoon, on the northern coast of Papua New Guinea (PNG), distinct groups of foraminifera, defined by numerical Q-mode cluster analysis of foraminiferal species occurrences, occupy four major environments and sedimentary regimes, generally aligned parallel to the coast: (1) the harbor and bay inlets, which have large fresh-water runoff and organic detrital inputs; (2) the fringing reefs along the west side of the lagoon which are influenced by coastal factors such as overhanging mangroves or fresh-water runoff; (3) the central lagoon floor which is over 50 m deep and covered with fine sand and patch reefs rising from it; and (4) the reef barrier with adjacent live coral-covered fore-reef slope and generally sandy back-reef slope. The four clusters are also mirrored in both species richness and Fisher alpha diversity analysis. Cluster 4 includes 79 species of large, thick-shelled miliolids, robust agglutinated species, calcarinids, and amphisteginids (Fisher alpha greater than or equal to20) that occur on the coral-rich barrier reef and back-reef. Cluster 3 has 50 species (Fisher alpha=8-20) and occupies the central lagoon floor. Cluster 2 has 25 or fewer species (Fisher alpha=2-6) and occurs on the shallow fringing reefs. Cluster 1 is the least diverse (less than or equal to7 species, Fisher alpha less than or equal to2) and occurs in the harbors and bays in the mouths of larger rivers and streams. The larger, endosymbiont-bearing foraminifera (alveolinellids, soritids, amphisteginids, nummulitids, and calcarinids) generally live on the back- and fore-reef slopes and in the lagoon, avoid the organic-rich coastal and harbor habitats, and preferentially dwell in well-lit environments to the bottom of the lagoon. The river mouths and bays are unusual for reef systems because of their high organic content, which creates low-oxygen and nutrient-rich conditions. Here the foraminiferal fauna is dominated by only a few and, for the most part, particularly thin-shelled and highly fragile species. Each faunal group contains a number of numerically abundant indicator species that do not occur in other faunal clusters. This implies low horizontal transport rates within the reef and lagoon complex and signifies that faunal mixing among the cluster groups is limited. Foraminiferal death assemblages may thus be autochthonous and retain information regarding the original community structure. They may also preserve environmental information useful in paleoecological studies and they are good ecological indicators of reef and lagoon habitats.