Department of Ecology and Coastal Management, Instituto de Ciencias Marinas de Andalucía (CSIC), Cádiz, Spain.
PLoS One. 2010 Nov 3;5(11):e13793. doi: 10.1371/journal.pone.0013793.
A number of causes have been proposed to account for the occurrence of gelatinous zooplankton (both jellyfish and ctenophore) blooms. Jellyfish species have a complex life history involving a benthic asexual phase (polyp) and a pelagic sexual phase (medusa). Strong environmental control of jellyfish life cycles is suspected, but not fully understood. This study presents a comprehensive analysis on the physicochemical conditions that control the survival and phase transition of Cotylorhiza tuberculata; a scyphozoan that generates large outbreaks in the Mediterranean Sea. Laboratory experiments indicated that the influence of temperature on strobilation and polyp survival was the critical factor controlling the capacity of this species to proliferate. Early life stages were less sensitive to other factors such as salinity variations or the competitive advantage provided by zooxanthellae in a context of coastal eutrophication. Coherently with laboratory results, the presence/absence of outbreaks of this jellyfish in a particular year seems to be driven by temperature. This is the first time the environmental forcing of the mechanism driving the life cycle of a jellyfish has been disentangled via laboratory experimentation. Projecting this understanding to a field population under climatological variability results in a pattern coherent with in situ records.
已经提出了许多原因来解释凝胶状浮游动物（水母和栉水母）大量出现的现象。水母物种的生命周期非常复杂，包括底栖无性阶段（息肉）和浮游性有性阶段（水螅体）。人们怀疑水母的生命周期受到强烈的环境控制，但还不完全清楚。本研究对控制栉水母生存和相变的理化条件进行了全面分析；这种栉水母在地中海大量爆发。实验室实验表明，温度对水螅体形成和息肉体生存的影响是控制该物种增殖能力的关键因素。早期生命阶段对盐度变化或沿海富营养化条件下共生藻提供的竞争优势等其他因素的敏感性较低。与实验室结果一致的是，这种水母在特定年份是否爆发似乎是由温度驱动的。这是首次通过实验室实验揭示了驱动水母生命周期的机制的环境驱动力。将这种理解应用于气候变异性下的实地种群，结果与现场记录一致。
