Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, Rimouski, Québec, Canada.
PLoS One. 2013 Sep 10;8(9):e74077. doi: 10.1371/journal.pone.0074077. eCollection 2013.
The diversity-ecosystem function relationship is an important topic in ecology but has not received much attention in Arctic environments, and has rarely been tested for its stability in time. We studied the temporal variability of benthic ecosystem functioning at hotspots (sites with high benthic boundary fluxes) and coldspots (sites with lower fluxes) across two years in the Canadian Arctic. Benthic remineralisation function was measured as fluxes of oxygen, silicic acid, phosphate, nitrate and nitrite at the sediment-water interface. In addition we determined sediment pigment concentration and taxonomic and functional macrobenthic diversity. To separate temporal from spatial variability, we sampled the same nine sites from the Mackenzie Shelf to Baffin Bay during the same season (summer or fall) in 2008 and 2009. We observed that temporal variability of benthic remineralisation function at hotspots is higher than at coldspots and that taxonomic and functional macrobenthic diversity did not change significantly between years. Temporal variability of food availability (i.e., sediment surface pigment concentration) seemed higher at coldspot than at hotspot areas. Sediment chlorophyll a (Chl a) concentration, taxonomic richness, total abundance, water depth and abundance of the largest gallery-burrowing polychaete Lumbrineristetraura together explained 42% of the total variation in fluxes. Food supply proxies (i.e., sediment Chl a and depth) split hot- from coldspot stations and explained variation on the axis of temporal variability, and macrofaunal community parameters explained variation mostly along the axis separating eastern from western sites with hot- or coldspot regimes. We conclude that variability in benthic remineralisation function, food supply and diversity will react to climate change on different time scales, and that their interactive effects may hide the detection of progressive change, particularly at hotspots. Time-series of benthic functions and its related parameters should be conducted at both hot- and coldspots to produce reliable predictive models.
多样性-生态系统功能关系是生态学中的一个重要课题，但在北极环境中并未受到太多关注，其时间稳定性也很少得到检验。我们研究了加拿大北极地区两年间热点（边界通量较高的地点）和冷点（通量较低的地点）底层生态系统功能的时间可变性。底层再矿化功能通过在沉积物-水界面测量氧气、硅酸、磷酸盐、硝酸盐和亚硝酸盐的通量来衡量。此外，我们还测定了沉积物色素浓度以及分类学和功能上的大型底栖生物多样性。为了将时间变化与空间变化分开，我们在 2008 年和 2009 年的同一季节（夏季或秋季）在麦肯齐架和巴芬湾从同一九个地点进行采样。我们观察到，热点底层再矿化功能的时间可变性高于冷点，并且分类学和功能上的大型底栖生物多样性在两年之间没有明显变化。食物供应（即沉积物表面色素浓度）的时间可变性在冷点似乎高于热点区域。沉积物叶绿素 a（Chl a）浓度、分类丰富度、总丰度、水深和最大画廊挖掘多毛类动物 Lumbrineristetraura 的丰度共同解释了通量总变化的 42%。食物供应指标（即沉积物 Chl a 和水深）将热点与冷点站分开，并解释了时间可变性轴上的变化，而大型底栖动物群落参数主要沿着将东部和西部站点与热点或冷点区分开的轴解释了变化。我们得出结论，底层再矿化功能、食物供应和多样性的可变性将在不同的时间尺度上对气候变化做出反应，它们的相互作用可能会掩盖渐进变化的检测，特别是在热点地区。应该在热点和冷点处进行底层功能及其相关参数的时间序列研究，以生成可靠的预测模型。
