Dipartimento di Scienze Della Vita e Dell'Ambiente, Università Degli Studi Di Cagliari, 09126, Cagliari, Italy.
Scuola Universitaria Superiore IUSS Pavia, 27100, Pavia, Italy.
Sci Rep. 2023 Jul 18;13(1):11558. doi: 10.1038/s41598-023-38543-6.
Eutrophication affects coastal oceans worldwide, modifies primary production and sediment biogeochemistry and, overall, is progressively compromising marine ecosystems' integrity. Because of their known bioturbation ability, sea cucumbers are supposed to be candidates for mitigating benthic eutrophication. To provide insights on this, we investigated differences in organic matter quantity and biochemical composition (as proxies of benthic trophic status) of sediments and feces of the sea cucumber Holothuria tubulosa acclimated in mesocosms at temperatures comprised between natural conditions (14-26 °C) and an extreme of 29 °C (representing the highest anomaly under heat waves in the Mediterrranean Sea). Organic matter features differed significantly between sediments characterized by different trophic statuses and the holothuroid's feces, though with some exceptions. Feces resulted almost always organically enriched when compared with the ambient sediments, though with variable differences in composition in sediments characterized by different initial trophic status. Our results point out that sea cucumbers maintain their bioreactor capacity at all experimental temperatures including the (anomalous) highest one, irrespectively of the available food, suggesting that they could be profitably utilized to mitigate benthic eutrophication also in a warmer Mediterranean Sea.
富营养化影响着全球的沿海海洋，改变了初级生产力和沉积物生物地球化学，并且总体上逐渐损害了海洋生态系统的完整性。由于海参已知的生物搅动能力，它们被认为是缓解底栖富营养化的候选者。为了对此提供深入了解，我们研究了在中观模型中适应温度在自然条件（14-26°C）和 29°C 之间（代表地中海热浪中的最高异常）之间的海参 Holothuria tubulosa 的沉积物和粪便中的有机物数量和生化组成（作为底栖营养状况的代表）之间的差异。具有不同营养状况的沉积物与海参的粪便之间的有机物特征存在显著差异，尽管存在一些例外。与环境沉积物相比，粪便中的有机物通常总是更丰富，尽管在具有不同初始营养状况的沉积物中，组成上存在可变的差异。我们的研究结果表明，海参在所有实验温度下（包括异常的最高温度）都保持着其生物反应器的能力，无论可用食物如何，这表明它们可以在更温暖的地中海中被有利地利用来缓解底栖富营养化。
