据Danielle Dixson 和 Mark Hay披露,海藻的过度生长是珊瑚礁的一个主要问题,而珊瑚礁所受到的所有主要的压力——从过度捕捞至气候变化——都会促使这一问题更加严重。海藻似乎是当其非常接近珊瑚时才会造成这种损害的,因此Dixson 和 Hay推测,生活在珊瑚礁中的食草鱼类可能会通过吃那些生长在珊瑚礁上的海藻来保护珊瑚的。
他们在研究斐济珊瑚礁时分析了鹿角珊瑚的群落——这种珊瑚在很大程度上导致了该珊瑚礁结构的复杂性——以及它们与居住在珊瑚礁中的,包括虾虎鱼在内的多种鱼类的相互作用。
在与海藻甚或只是与海藻的化学提取物接触的几分钟内,这些珊瑚虫便会释放一种气味,这种气味会招募虾虎鱼来除掉这些海藻并大大减少否则会给珊瑚带来的伤害。反过来,这些虾虎鱼在吃了这些海藻之后也令捕食动物对其感到更不合口味。
文章的作者提出,这种互惠关系可能是对应蚂蚁与金合欢树之间关系的海洋中的例子。(生物谷Bioon.com)
doi: 10.1126/science.1225748
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Corals Chemically Cue Mutualistic Fishes to Remove Competing Seaweeds
Danielle L. Dixson, Mark E. Hay
Corals in the genus Acropora generate much of the structural complexity upon which coral reefs depend, but they are susceptible to damage from toxic seaweeds. Acropora nasuta minimizes this damage by chemically cuing symbiotic goby fishes (Gobiodon histrio or Paragobiodon echinocephalus) to remove the toxic seaweed Chlorodesmis fastigiata. Within minutes of seaweed contact, or contact from only seaweed chemical extract, the coral releases an odor that recruits gobies to trim the seaweed and dramatically reduce coral damage that would otherwise occur. In turn, chemically defended gobies become more toxic after consumption of this noxious alga. Mutualistic gobies and corals appear to represent a marine parallel to terrestrial ant-plants, in that the host provides shelter and food in return for protection from natural enemies.