Ecklonia radiata is the main foundation species in Australian temperate reefs, yet little has been published on its reproduction and how this may change across its depth range (1–50+ m). In this study, we examined differences in sporophyte morphology and zoospore production during a reproductive season and across four depths (7, 15, 25, and 40 m). Additionally, we examined differences in germination rate, survival, and morphological traits of gametophytes obtained from these four depths, cultured under the same light and temperature conditions. Multivariate morphology of sporophytes differed significantly between deep (~40 m) and shallow sites (7 and 15 m), but individual morphological traits were not significantly different across depths. Total spore production was similar across depths but the peak of zoospore release was observed in February at 15 m of depth (6,154 zoospores · mm⁻² of tissue) and the minimum observed in January at 7, 25, and 40 m (1,141, 987, and 214 zoospores · mm⁻² of tissue, respectively). The source depth of zoospores did not have an influence in the germination rate or the survival of gametophytes, and only gametophytes sourced from 40 m sites presented significantly less surface area and number of branches. Overall, these results indicate that E. radiata’s reproductive performance does not change across its depth range and that kelp beds reproducing in deeper areas may contribute to the replenishment of their shallow counterparts. We propose that deep kelps may constitute a mechanism of resilience against climate change and anthropogenic disturbances.

中文翻译：

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海带早期生命阶段的生殖产出，深度同步和源深度的影响

辐射菌是澳大利亚温带珊瑚礁的主要基础物种，但关于其繁殖以及在其深度范围（1–50 + m）中可能如何变化的报道很少。在这项研究中，我们研究了繁殖季节和四个深度（7、15、25和40 m）孢子体形态和游动孢子产生的差异。此外，我们检查了在相同的光照和温度条件下培养的从这四个深度获得的配子体发芽率，存活率和形态特征的差异。孢子体的多变量形态在深处（〜40 m）和浅处（7和15 m）之间存在显着差异，但各个形态特征在不同深度之间没有显着差异。^-2组织）和一月在7、25和40 m处观察到的最小值（分别为1,141、987和214游动孢子·mm ^-2组织）。游动孢子的来源深度对配子体的发芽率或存活率没有影响，只有来自40 m部位的配子体的表面积和分支数量明显减少。总体而言，这些结果表明辐射大肠埃希氏菌的繁殖性能在其整个深度范围内都没有变化，并且在较深区域繁殖的海藻床可能有助于补充浅海藻。我们建议，深海带可能构成抵御气候变化和人为干扰的复原机制。