Response of the benthic foraminiferal community to a simulated short-term phytodetritus pulse in the abyssal North Pacific
Response of the benthic foraminiferal community to a simulated short-term phytodetritus pulse in the abyssal North Pacific
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DOI：
10.3354/meps09298
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发表时间：
2011-01-01
影响因子：
2.5
通讯作者：
Heinz, Petra
中科院分区：
文献类型：
--
作者：
Enge, Annekatrin J.;Nomaki, Hidetaka;Heinz, Petra
有孔虫是深海生态系统中的一个重要的动物单元，主要依靠光层沉积的颗粒状有机质来维持其生长和繁殖的新陈代谢。然而，它们在深海沉积物碳循环中的作用还没有得到充分的研究。我们调查了东北太平洋M站(4000米深)的底栖有孔虫，并在一次就地取食实验中评估了个体物种对模拟植物碎屑脉冲的反应。将C-13标记的硅藻(Thalassiosira Weissflgii)应用于沉积物表面，培养4d。上部3厘米的活有孔虫群落(>；0.063 mm)包含>；100种，主要由少数软壁有孔虫组成。整个活体有孔虫群落的种群密度在沉积物表面最高(平均+/-SD=279+/-72个)。10 cm(-3)背景和C-13孵化岩心)，并随着深度的增加而逐渐减少。不同物种和不同深度之间对藻类物质的吸收有很大差异。在实验过程中，摄入了0.82mgCm(-2)，主要来自钙质有孔虫(约占60%)和凝集有孔虫(约占40%)。沉积物表层的吸纳量最高，而更深的沉积层的吸纳量则低3-5倍。尽管有孔虫群落具有明显的生命力和强大的代表性，但这些软壁物种对所提供的藻类材料没有表现出明显的反应。我们的结论是，软壁有孔虫可能对深海海底短期的植物碎屑物质循环并不重要。
Foraminifera are an important faunal element of the abyssal ecosystem and largely depend on deposited particulate organic matter from the photic zone to sustain their metabolism for growth and reproduction. However, their role in the carbon cycle in deep-sea sediments is insufficiently studied. We investigated benthic foraminifera at Station M (4000 m depth) in the Northeast Pacific and assessed the response of individual species to a simulated phytodetritus pulse during an in situ feeding experiment. Sediments were incubated for 4 d with C-13-labeled diatoms (Thalassiosira weissflogii) applied to the sediment surface. The living foraminiferal community (>0.063 mm) of the upper 3 cm contained >100 species and was strongly dominated by a few taxa of soft-walled saccamminids. Population density of the entire living foraminiferal community was highest at the sediment surface (mean +/- SD = 279 +/- 72 ind. 10 cm(-3) in background and C-13-incubated cores) and decreased gradually with depth. Large differences were observed in the uptake of the algal material among species and between depth levels. During the experiment, 0.82 mg C m(-2) were ingested, mainly by calcareous (similar to 60%) and agglutinated (similar to 40%) foraminifera. Uptake was highest at the sediment surface and 3 to 5 times less in deeper sediment horizons. Despite clear signs of vitality and a strong representation in the foraminiferal community, none of the soft-walled species showed a noticeable response to the offered algal material. We conclude that soft-walled foraminifera may not be important to the short-term phytodetrital matter cycling at the abyssal sea floor.