Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, the Netherlands.
Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94240, 1090 GE Amsterdam, the Netherlands.
Curr Biol. 2022 Sep 12;32(17):3855-3861.e3. doi: 10.1016/j.cub.2022.07.017. Epub 2022 Aug 10.
Sponges, among the oldest extant multicellular organisms on Earth, play a key role in the cycling of nutrients in many aquatic ecosystems. They need to employ strategies to prevent clogging of their internal filter system by solid wastes, but self-cleaning mechanisms are largely unknown. It is commonly assumed that sponges remove solid waste with the outflowing water through distinct outflow openings (oscula). Here, we present time-lapse video footage and analyses of sponge waste revealing a completely different mechanism of particle removal in the Caribbean tube sponge Aplysina archeri. This sponge actively moves particle-trapping mucus against the direction of its internal water flow and ejects it into the surrounding water from its seawater inlet pores (ostia) through periodic surface contractions that have been described earlier as "sneezing." Visually, it appears as if the sponge is continuously streaming mucus-embedded particles and sneezes to shed this particulate waste, resulting in a notable flux of detritus that is actively consumed by sponge-associated fauna. The new data are used to estimate production of detritus for this abundant sponge on Caribbean coral reefs. Last, we discuss why waste removal from the sponge inhalant pores may be a common feature among sponges and compare the process in sponges to equivalent mechanisms of mucus transport in other animals, including humans.
海绵动物是地球上现存最古老的多细胞生物之一，在许多水生生态系统的营养循环中起着关键作用。它们需要采取策略来防止固体废物堵塞其内部过滤系统，但自我清洁机制在很大程度上尚不清楚。人们通常认为，海绵动物通过独特的出水孔（腔口）将固体废物随水流带出。在这里，我们展示了加勒比管海绵 Aplysina archeri 中颗粒去除的延时视频和分析，揭示了一种完全不同的机制。这种海绵会主动将捕获颗粒的黏液逆着内部水流的方向移动，并通过先前描述的周期性表面收缩将其从海水入口孔（口）喷射到周围的水中，这种收缩被称为“打喷嚏”。从视觉上看，海绵似乎在不断地流出含有颗粒的黏液，并通过“打喷嚏”来清除这些颗粒状废物，从而导致大量碎屑明显地被海绵相关动物群消耗。新数据被用于估计加勒比珊瑚礁上这种丰富海绵的碎屑产量。最后，我们讨论了为什么从海绵的吸入孔去除废物可能是海绵的一个共同特征，并将这个过程与其他动物（包括人类）中类似的黏液运输机制进行了比较。
