Department of Bioscience, Biotechnology and Environment, University of Bari, Bari, Italy.
Department of Integrative Marine Ecology, Zoological Station "Anton Dohrn", Naples, Italy.
PeerJ. 2023 Feb 23;11:e14685. doi: 10.7717/peerj.14685. eCollection 2023.
The demosponge is characterized by wide geographic distribution and great adaptability to numerous and highly variable climatic and hydrological conditions. Indeed, the species can colonize many different environments, including several unusual ones, such as concrete drainage conduits of a marine land-based fish farm plant. This research aimed to enhance existing knowledge on the reproductive cycle and growth performance of while also evaluating the impact of a controlled supply of trophic resources, wastewater flow and constant water temperature on these biological traits.
Specimens included in this one-year study inhabited drainage conduits of a land-based fish farm. The approach included measurements of sponge biomass and occurrence and abundance of reproductive elements across different seasons and environmental parameters, such as fish biomass, trophic resources, and wastewater flow. Sponge growth and reproductive elements, including oocytes, spermatic cysts, and embryos, were measured monthly in sponges positioned in the drainage conduit, thus with different trophic resources but with constant water temperature. Finally, we used generalized additive models to describe variables that contribute the most to the growth of sponges.
Growth performance showed marked variations during the study period. The highest increase in sponge volume was observed from August/September to January/March. The volume of sponges was principally determined by the reduction of reared fish biomass and the increase of pellet amount and wastewater flow. Sponge specimens exhibited an active state during the entire study, as proven by the occurrence of recruits. However, sexual elements were only sporadically observed, thus not permitting the recognition of a true sexual cycle.
The results of the present study confirmed that exhibits high flexibility and adaptability to the differential, and somewhat extreme, environmental conditions. Indeed, this species can live, grow and reproduce in the drainage conduits of the fish farm, where the species face constant darkness, water temperature and continuous nutritional supply. In such conditions, display an active state during the entire year, while avoiding stages of decline and long dormancy usually observed in wild populations. It seems plausible that stable environmental conditions induce an almost continuous sexual phase, probably under the control of endogenous factors. No asexual elements were detected, although it was impossible to exclude the contribution of asexual reproduction in the origin of the newly settled sponges, which were repeatedly detected throughout the study. The growth performance seemed linked to the fish farm conditions, thus providing useful indications on the best maintenance conditions for in land-based integrated multitrophic systems, where the species could be used for wastewater treatment.
普通海绵的特点是地理分布广泛，对众多高度可变的气候和水文条件具有很强的适应性。事实上，这种物种可以在许多不同的环境中生存，包括一些不寻常的环境，如海洋陆基鱼类养殖场的混凝土排水管道。本研究旨在提高对 繁殖周期和生长性能的现有认识，同时评估营养资源、污水流量和恒定水温的受控供应对这些生物特征的影响。
本研究中包含的标本栖息在陆基鱼类养殖场的排水管道中。该方法包括在不同季节和环境参数（如鱼类生物量、营养资源和污水流量）下测量海绵生物量和有性繁殖元素的发生和丰度。在排水管道中定位的海绵中每月测量海绵的生长和有性繁殖元素，包括卵母细胞、精子囊和胚胎，因此具有不同的营养资源，但具有恒定的水温。最后，我们使用广义加性模型来描述对海绵生长贡献最大的变量。
生长性能在研究期间表现出明显的变化。从 8 月/9 月到 1 月/3 月，海绵体积增加幅度最大。海绵体积主要取决于养殖鱼类生物量的减少、颗粒数量的增加和污水流量的增加。海绵标本在整个研究期间表现出活跃状态，这证明了新个体的出现。然而，只有偶尔观察到有性繁殖元素，因此无法识别真正的有性繁殖周期。
本研究结果证实， 表现出对不同且有些极端的环境条件的高度灵活性和适应性。事实上，这种物种可以在鱼类养殖场的排水管道中生存、生长和繁殖，在那里，它们面临着持续的黑暗、水温恒定和持续的营养供应。在这种情况下， 在整个一年中都表现出活跃状态，同时避免了在野生种群中观察到的衰退和长期休眠阶段。似乎稳定的环境条件会诱导几乎连续的有性阶段，可能受内源性因素的控制。虽然无法排除新定居海绵的无性繁殖在起源中的贡献，但没有检测到无性繁殖元素，这些海绵在整个研究中都被反复检测到。生长性能似乎与鱼类养殖场的条件有关，因此为陆基综合多营养系统中 的最佳维护条件提供了有用的指示，在这种系统中， 可以用于处理污水。
