Molinero Juan Carlos, Ibanez Fréderic, Souissi Sami, Chifflet Marina, Nival Paul
Laboratoire d'Océanographie de Villefranche (LOV), Station Zoologique-BP 28, 06234 Villefranche-sur-mer, France.
Oecologia. 2005 Oct;145(4):640-9. doi: 10.1007/s00442-005-0130-4. Epub 2005 Oct 13.
Planktonic copepods play a major role in the fluxes of matter and energy in the marine ecosystem, provide a biological pump of carbon into the deep ocean, and play a role in determining fish recruitment. Owing to such ecological considerations, it is essential to understand the role that climate might play in the interannual variability of these organisms and the mechanisms by which it could modify the ecosystem functioning. In this study, a causal chain of meteorological, hydrological and ecological processes linked to the North Atlantic Oscillation (NAO) was identified in the Ligurian Sea, Northwestern Mediterranean. The forcing by the NAO drives most of the hydro-climatic variability during winter and early spring. Subsequently, interannual and decadal changes of the dominant copepods Centropages typicus and Temora stylifera were significantly correlated to the state of the hydro-climatic signal and tightly coupled to the NAO. Direct and indirect effects whose influence promoted phenological changes in the two copepod populations drove the species' responses to climatic forcing. Opposite responses of the analysed species were also highlighted by these results. While years characterized by the positive phase of the NAO leads to enhancement of the strength and the forward move of the C. typicus peak, they act negatively on the annual cycle of T. stylifera, the abundance of which drops twofold and the annual peak appears delayed in time. In contrast, low NAO years lead to high abundance of T. stylifera and a forward timing of its peak, and acts in turn negatively on the C. typicus annual cycle in both abundance (low) and timing (delayed). Owing to the synchronism between hydro-climatic conditions and the NAO, and the major role of these species in the pelagic ecosystem of the studied area, these results provide key elements for interpreting and forecasting decadal changes of planktonic populations in the Ligurian Sea.
浮游桡足类在海洋生态系统的物质和能量流动中发挥着重要作用，为碳进入深海提供生物泵，并在决定鱼类补充方面发挥作用。出于这些生态考虑，了解气候在这些生物的年际变化中可能扮演的角色以及它改变生态系统功能的机制至关重要。在本研究中，在地中海西北部的利古里亚海确定了与北大西洋涛动（NAO）相关的气象、水文和生态过程的因果链。NAO的强迫驱动了冬季和早春期间大部分的水文气候变率。随后，优势桡足类典型真刺水蚤和中华哲水蚤的年际和年代际变化与水文气候信号的状态显著相关，并与NAO紧密耦合。直接和间接影响促进了这两种桡足类种群的物候变化，从而驱动了物种对气候强迫的响应。这些结果还突出了所分析物种的相反响应。以NAO正相位为特征的年份会导致典型真刺水蚤峰值强度增强和前移，而对中华哲水蚤的年周期产生负面影响，其丰度下降两倍且年峰值出现时间延迟。相比之下，低NAO年份会导致中华哲水蚤丰度高且峰值提前出现，进而对典型真刺水蚤的年周期在丰度（低）和时间（延迟）方面都产生负面影响。由于水文气候条件与NAO之间的同步性，以及这些物种在所研究区域的浮游生态系统中的主要作用，这些结果为解释和预测利古里亚海浮游生物种群的年代际变化提供了关键要素。
