Escuela de Ciencias del Mar, Facultad de Ecología y Recursos Naturales, Universidad Andrés Bello, Santiago, Chile.
Coastal Ecology Laboratory, Department of Biology, University of Prince Edward Island, Charlottetown, PE, Canada.
PLoS One. 2018 Apr 19;13(4):e0196121. doi: 10.1371/journal.pone.0196121. eCollection 2018.
The transfer of seaweeds from subtidal bottoms to nearby intertidal rocky shores is a common but often overlooked phenomenon. Freshly detached seaweeds often represent critical trophic subsidies for herbivores living in upper-shore rocky intertidal areas, such as the marine snail Diloma nigerrima. This species relies on three species of seaweeds for food and displays feeding strategies to deal with a resource that is scarce and at times unpredictable. This study focused on the nutritional quality of freshly detached algae (Durvillaea antarctica, Lessonia spicata and Lessonia trabeculata) and measured Diloma nigerrima's algal consumption rates in trials with and without choice. Absorption efficiency and growth of individual snails fed on each alga were also measured. Durvillaea antarctica had the highest nutritional quality and was the most consumed algae in both single and multiple-choice trials. Absorption efficiency was also highest for D. antarctica but growth rates of snails fed with this species were similar to those fed with the other algae. Combined, these results suggest that D. nigerrima has the ability to discriminate among seaweeds based on their nutritional quality. A potential increase in oxygen uptake when D. nigerrima is consuming the preferred food item is also proposed as a plausible hypothesis to explain the mismatch between snails' preference and growth rate. These results aim to guide further studies on trophic subsidies and their role in coastal systems.
海藻从亚潮带底部向附近潮间带岩石海岸的转移是一种常见但经常被忽视的现象。刚脱离的海藻通常是生活在上层潮间带岩石区的草食动物的关键营养物质，例如海洋蜗牛 Diloma nigerrima。该物种依赖三种海藻作为食物，并展示了应对稀缺和不可预测资源的觅食策略。本研究集中于刚脱离的藻类（ Durvillaea antarctica 、 Lessonia spicata 和 Lessonia trabeculata ）的营养质量，并在有和没有选择的情况下测量了 Diloma nigerrima 对藻类的消耗率。还测量了每种藻类喂养的单个蜗牛的吸收效率和生长情况。 Durvillaea antarctica 具有最高的营养质量，并且在单种和多种选择试验中都是最受欢迎的藻类。 D. antarctica 的吸收效率也最高，但用该物种喂养的蜗牛的生长速度与用其他藻类喂养的蜗牛相似。综合这些结果表明， D. nigerrima 能够根据其营养质量来区分海藻。还提出了当 D. nigerrima 消耗首选食物时氧气摄取量增加的可能性，作为解释蜗牛偏好与生长速度不匹配的合理假设。这些结果旨在指导关于营养物质和它们在沿海系统中的作用的进一步研究。
