Prospects for survival in the Southern Ocean: vulnerability of benthic species to temperature change
Prospects for survival in the Southern Ocean: vulnerability of benthic species to temperature change
复制标题
南大洋的生存前景：底栖物种对温度变化的脆弱性
作者：
L. Peck
生物体在不断变化的环境中提高生存能力的反应数量有限。他们可以：1.科普在现有的生理灵活性; 2.适应变化的环境; 3。迁移到允许生存的地点。与其他地方的物种相比，居住在南极洲周围沿海海底的物种应对变化的生理能力较差。当温度仅比年平均温度高5-10°C时，它们就会死亡，许多物种失去了执行基本功能的能力，例如，当温度仅升高2-3°C时，它们会在扇贝中游泳或被动物群中的双壳软体动物掩埋。适应或进化新角色以适应不断变化的条件的能力至少部分取决于世代时间。南极底栖物种生长缓慢，发育速度往往比类似的温带物种慢5 - 10倍。他们也活到很大的年龄，并表现出延迟成熟。较长的世代时间减少了产生新突变的机会，并导致适应变化的能力较差。在新的地点定居和迁移离开恶化的条件的内在能力取决于成年人的能力，迁移在很大的距离，或生殖阶段漂移的时间延长。南极底栖物种的缓慢发展意味着它们的幼虫确实在水柱中度过了很长的时间。然而，虽然大多数大陆的海岸线跨越很大的纬度范围，但南极洲的轮廓几乎是圆形的，被绕极流与其他海洋隔离开来，其海岸线覆盖的纬度很少。因此，在一个变暖的环境中，可供迁徙的地方越来越少。在所有三个主要标准上，南极海底物种似乎比其他地方的物种更不能够以提高生存率的方式对变化作出反应。
Organisms have a limited number of responses that enhance survival in changing environments. They can: 1. Cope within existing physiological flexibility; 2. Adapt to changing conditions; or 3. Migrate to sites that allow survival. Species inhabiting coastal seabed sites around Antarctica have poorer physiological capacities to deal with change than species elsewhere. They die when temperatures are raised by only 5–10°C above the annual average, and many species lose the ability to perform essential functions, e.g. swimming in scallops or burying in infaunal bivalve molluscs when temperatures are raised only 2–3°C. The ability to adapt, or evolve new characters to changing conditions depends, at least in part, on generation time. Antarctic benthic species grow slowly and develop at rates often x5–x10 slower than similar temperate species. They also live to great age, and exhibit deferred maturity. Longer generation times reduce the opportunities to produce novel mutations, and result in poorer capacities to adapt to change. Intrinsic capacities to colonize new sites and migrate away from deteriorating conditions depend on adult abilities to locomote over large distances, or for reproductive stages to drift for extended periods. The slow development of Antarctic benthic species means their larvae do spend extended periods in the water column. However, whereas most continents have coastlines extending over a wide range of latitude, Antarctica is almost circular in outline, is isolated from other oceans by the circumpolar current, and its coastline covers few degrees of latitude. Thus in a warming environment there are fewer places to migrate to. On all three major criteria Antarctic benthic species appear less capable than species elsewhere of responding to change in ways that can enhance survival.