俗话说，4月的小雨带来5月的鲜花，然而4月的污染却带来5月的水母“怒放”。
研究人员发现，成千上万的这种生物季节性地突然出现，往往发生在因气候变化而变得温暖的水域，或是因人类的过度捕捞而为好斗的水母消灭了食物竞争对手的水域。
为了搞清水母的过量繁殖对海洋食物链产生了何种影响，美国格点市弗吉尼亚海洋科学研究所的海洋学家Robert H. Condon和同事，对每年夏季在美国切萨皮克湾大量出现的两种水母进行了研究。结果显示，当这些水母以浮游生物和其他固碳生物体为食后，它们会将食物转化为一种凝胶状的、富含碳的排泄物。
他们进而发现，一些通常很罕见细菌会迅速吃掉这些排泄物，并将其中的碳转化为二氧化碳气体。研究人员在最近的美国《国家科学院院刊》网络版上报告了这一研究成果。
Condon指出，这一过程能够除去海水中的碳，从而妨碍鱼类和其他生物体将碳作为一种食物来源，并最终饿死一些海洋生物。研究人员表示，水母的大量出现并不意味着环境得到了改善，恰恰相反，这是一种环境恶化的表现。
随着水污染的加剧，营养物质过剩，灾难性的浮游生物大量出现，导致鱼类大批死亡，水母开始繁盛。但这只是另一个灾难的开始，水母什么都吃，浮游生物、鱼卵、小鱼、大鱼……水母的大量繁殖让鱼类难以再生。研究人员指出，改变这种情况目前主要有两种方法。一是解决水污染问题，二是对一些海洋生物，特别是水母的天敌海龟加以保护。（生物谷Bioon.com）
生物谷推荐原文出处：
Proceedings of the National Academy of Sciences DOI： 10.1073/pnas.1015782108
Jellyfish blooms result in a major microbial respiratory sink of carbon in marine systems
Condon, Robert H.; Steinberg, Deborah K.; del Giorgio, Paul A.; Bouvier, Thierry C.; Bronk, Deborah A.; Graham, William M.; Ducklow, Hugh W.
Jellyfish blooms occur in many estuarine and coastal regions and may be increasing in their magnitude and extent worldwide.Voracious jellyfish predation impacts food webs by converting large quantities of carbon (C), fixed by primary producers andconsumed by secondary producers, into gelatinous biomass, which restricts C transfer to higher trophic levels because jellyfishare not readily consumed by other predators. In addition, jellyfish release colloidal and dissolved organic matter (jelly-DOM),and could further influence the functioning of coastal systems by altering microbial nutrient and DOM pathways, yet the linksbetween jellyfish and bacterioplankton metabolism and community structure are unknown. Here we report that jellyfish releasedsubstantial quantities of extremely labile C-rich DOM, relative to nitrogen (25.6 ± 31.6 C:1N), which was quickly metabolizedby bacterioplankton at uptake rates two to six times that of bulk DOM pools. When jelly-DOM was consumed it was shunted towardbacterial respiration rather than production, significantly reducing bacterial growth efficiencies by 10% to 15%. Jelly-DOMalso favored the rapid growth and dominance of specific bacterial phylogenetic groups (primarily γ-proteobacteria) that were rare in ambient waters, implying that jelly-DOM was channeled through a small component of the in situ microbialassemblage and thus induced large changes in community composition. Our findings suggest major shifts in microbial structureand function associated with jellyfish blooms, and a large detour of C toward bacterial CO2 production and away from higher trophic levels. These results further suggest fundamental transformations in the biogeochemicalfunctioning and biological structure of food webs associated with jellyfish blooms.
