Voulgaris Konstantinos, Varkoulis Anastasios, Zaoutsos Stefanos, Stratakis Antonios, Vafidis Dimitris
Department of Ichthyology and Aquatic Environment Nea Ionia, University of Thessaly Volos Greece.
Department of Energy Systems University of Thessaly Larisa Greece.
Ecol Evol. 2021 Dec 14;11(24):17734-17743. doi: 10.1002/ece3.8247. eCollection 2021 Dec.
In the Mediterranean, and are important drivers of benthic ecosystems, often coexisting in sublittoral communities. However, the introduction of the invasive diadematoid , which utilizes venomous spines, may affect these communities. To describe the mechanical properties of the test and spines of these three species, specimens were collected in winter of 2019 from the sublittoral zone of the Dodecanese island complex, southeastern Aegean Sea. This region serves as a gateway for invasive species to the Mediterranean Sea. Crushing test was conducted on live individuals, while 3-point bending test was used to estimate spine stiffness. Porosity and mineralogy of the test and spine, thickness of the test, and breaking length of the spine were measured and compared, while the microstructural architecture was also determined. The test of . was the most robust (194.35 ± 59.59 N), while the spines of . (4.76 ± 2.13 GPa) exhibited highest flexibility. Increased porosity and thickness of the test were related to increased robustness, whereas increased flexibility of the spine was attributed to high porosity, indicating that porosity in the skeleton plays a key role in preventing fracture. The spines of . exhibited highest length after fracture % (71.54 ± 5.5%). . exhibited higher values of Mg concentration in the test (10%) compared with the spines (4%). For the first time, the mineralogy of an invasive species is compared with its native counterpart, while a comparison of the mechanical properties of different species of the same ecosystem also takes place. This study highlights different ways, in which sea urchins utilize their skeleton and showcases the ecological significance of these adaptations, one of which is the different ways of utilization of the skeleton for defensive purposes, while the other is the ability of . to decrease the Mg % of its skeleton degrading its mechanical properties, without compromising its defense, by depending on venomous bearing spines. This enables this species to occupy not only tropical habitats, where it is indigenous, but also temperate like the eastern Mediterranean, which it has recently invaded.
在地中海地区，[具体物种1]和[具体物种2]是底栖生态系统的重要驱动因素，它们常常共存于亚潮带群落中。然而，利用有毒棘刺的入侵双带棘海胆的引入，可能会影响这些群落。为了描述这三个物种的壳和棘刺的力学性能，2019年冬季从爱琴海东南部多德卡尼斯群岛复合体的亚潮带区域采集了标本。该地区是入侵物种进入地中海的一个通道。对活体个体进行了抗压测试，同时采用三点弯曲试验来估计棘刺的刚度。测量并比较了壳和棘刺的孔隙率、矿物学、壳的厚度以及棘刺的断裂长度，同时还确定了微观结构。[具体物种1]的壳最坚固（194.35 ± 59.59牛），而[具体物种2]的棘刺（4.76 ± 2.13吉帕）表现出最高的柔韧性。壳的孔隙率和厚度增加与坚固性增强有关，而棘刺柔韧性的增加归因于高孔隙率，这表明骨骼中的孔隙率在防止骨折方面起着关键作用。[具体物种3]的棘刺在断裂后表现出最高的长度百分比（71.54 ± 5.5%）。[具体物种1]壳中的镁浓度（10%）高于其棘刺中的镁浓度（4%）。首次将入侵物种的矿物学与其本土对应物种进行了比较，同时也对同一生态系统中不同物种的力学性能进行了比较。这项研究突出了海胆利用其骨骼的不同方式，并展示了这些适应性的生态意义，其中之一是骨骼用于防御目的的不同利用方式，另一个是[具体物种3]通过依靠带毒棘刺来降低其骨骼中镁的百分比从而降低其力学性能，同时又不影响其防御能力。这使得该物种不仅能够占据其原生的热带栖息地，还能占据像东地中海这样它最近入侵的温带地区。
