俗話(huà)說(shuō),，4月的小雨帶來(lái)5月的鮮花,，然而4月的污染卻帶來(lái)5月的水母“怒放”。
研究人員發(fā)現(xiàn),，成千上萬(wàn)的這種生物季節(jié)性地突然出現(xiàn),，往往發(fā)生在因氣候變化而變得溫暖的水域，或是因人類(lèi)的過(guò)度捕撈而為好斗的水母消滅了食物競(jìng)爭(zhēng)對(duì)手的水域,。
為了搞清水母的過(guò)量繁殖對(duì)海洋食物鏈產(chǎn)生了何種影響,，美國(guó)格點(diǎn)市弗吉尼亞海洋科學(xué)研究所的海洋學(xué)家Robert H. Condon和同事，對(duì)每年夏季在美國(guó)切薩皮克灣大量出現(xiàn)的兩種水母進(jìn)行了研究,。結(jié)果顯示,，當(dāng)這些水母以浮游生物和其他固碳生物體為食后,，它們會(huì)將食物轉(zhuǎn)化為一種凝膠狀的、富含碳的排泄物,。
他們進(jìn)而發(fā)現(xiàn),，一些通常很罕見(jiàn)細(xì)菌會(huì)迅速吃掉這些排泄物，并將其中的碳轉(zhuǎn)化為二氧化碳?xì)怏w,。研究人員在最近的美國(guó)《國(guó)家科學(xué)院院刊》網(wǎng)絡(luò)版上報(bào)告了這一研究成果,。
Condon指出，這一過(guò)程能夠除去海水中的碳,，從而妨礙魚(yú)類(lèi)和其他生物體將碳作為一種食物來(lái)源,，并最終餓死一些海洋生物。研究人員表示,，水母的大量出現(xiàn)并不意味著環(huán)境得到了改善,，恰恰相反，這是一種環(huán)境惡化的表現(xiàn),。
隨著水污染的加劇,，營(yíng)養(yǎng)物質(zhì)過(guò)剩，災(zāi)難性的浮游生物大量出現(xiàn),，導(dǎo)致魚(yú)類(lèi)大批死亡,，水母開(kāi)始繁盛。但這只是另一個(gè)災(zāi)難的開(kāi)始,，水母什么都吃,，浮游生物、魚(yú)卵,、小魚(yú),、大魚(yú)……水母的大量繁殖讓魚(yú)類(lèi)難以再生。研究人員指出,，改變這種情況目前主要有兩種方法,。一是解決水污染問(wèn)題，二是對(duì)一些海洋生物,，特別是水母的天敵海龜加以保護(hù),。（生物谷Bioon.com）
生物谷推薦原文出處：
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.
