Lagos Marcelo E, Albarrán-Mélzer Natalia, Gaitán-Espitia Juan Diego
The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Hong Kong.
Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong.
Proc Biol Sci. 2025 Jul;292(2050):20250448. doi: 10.1098/rspb.2025.0448. Epub 2025 Jul 2.
In marine benthic environments, oxygen availability is highly variable across temporal and spatial scales. Such variability generates heterogeneous microhabitats in which organisms experience marked changes from saturated (i.e. normoxic) to anoxic conditions. For sessile colonial species, fine spatial differences in oxygen availability can trigger intra-colony phenotypic differences, influencing the overall colony performance/fitness. Here, we assessed the extent to which intra-colony differences in oxygen regimens influence biological characteristics in adult and larval stages of the colonial bryozoan . For this, we measured the critical sensitivity to low oxygen for upper and lower zones of adult colonies and their larvae. We also measured larval swimming-exploring behaviour and settlement under hypoxia and normoxia. Although the results show similar intra-colony tolerances in the adults, differences were found in their larvae. While the lower zones of the colonies showed higher tolerant larvae, the upper zones had larvae with higher sensitivity and a tendency to avoid low-oxygen microhabitats. These larvae settle more quickly and in greater numbers compared with their lower-zone counterparts. Our results suggest that intra-colony differences in sensitivity to low-oxygen conditions (particularly during larval stages) can be important regulators of ecological processes (e.g. recruitment) and the resilience of benthic colonial species in deoxygenated oceans.
在海洋底栖环境中，氧的可利用性在时间和空间尺度上变化很大。这种变化产生了异质微生境，生物在其中经历从饱和（即常氧）到缺氧条件的显著变化。对于固着的群体物种，氧可利用性的细微空间差异可引发群体内的表型差异，影响整个群体的性能/适应性。在此，我们评估了群体内氧状况差异对群体苔藓虫成虫和幼虫阶段生物学特征的影响程度。为此，我们测量了成年群体及其幼虫上下区域对低氧的临界敏感性。我们还测量了幼虫在缺氧和常氧条件下的游动探索行为和附着情况。虽然结果显示成虫群体内的耐受性相似，但在幼虫中发现了差异。群体的下部区域幼虫耐受性较高，而上部区域的幼虫敏感性较高，并有避开低氧微生境的倾向。与下部区域的幼虫相比，这些幼虫附着更快且数量更多。我们的结果表明，群体内对低氧条件敏感性的差异（特别是在幼虫阶段）可能是生态过程（如补充）和脱氧海洋中底栖群体物种恢复力的重要调节因素。
