Convey Peter, Gibson John A E, Hillenbrand Claus-Dieter, Hodgson Dominic A, Pugh Philip J A, Smellie John L, Stevens Mark I
British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK.
Biol Rev Camb Philos Soc. 2008 May;83(2):103-17. doi: 10.1111/j.1469-185X.2008.00034.x.
Antarctica is a continent locked in ice, with almost 99.7% of current terrain covered by permanent ice and snow, and clear evidence that, as recently as the Last Glacial Maximum (LGM), ice sheets were both thicker and much more extensive than they are now. Ice sheet modelling of both the LGM and estimated previous ice maxima across the continent give broad support to the concept that most if not all currently ice-free ground would have been overridden during previous glaciations. This has given rise to a widely held perception that all Mesozoic (pre-glacial) terrestrial life of Antarctica was wiped out by successive and deepening glacial events. The implicit conclusion of such destruction is that most, possibly all, contemporary terrestrial life has colonised the continent during subsequent periods of glacial retreat. However, several recently emerged and complementary strands of biological and geological research cannot be reconciled comfortably with the current reconstruction of Antarctic glacial history, and therefore provide a fundamental challenge to the existing paradigms. Here, we summarise and synthesise evidence across these lines of research. The emerging fundamental insights corroborate substantial elements of the contemporary Antarctic terrestrial biota being continuously isolated in situ on a multi-million year, even pre-Gondwana break-up timescale. This new and complex terrestrial Antarctic biogeography parallels recent work suggesting greater regionalisation and evolutionary isolation than previously suspected in the circum-Antarctic marine fauna. These findings both require the adoption of a new biological paradigm within Antarctica and challenge current understanding of Antarctic glacial history. This has major implications for our understanding of the key role of Antarctica in the Earth System.
南极洲是一个被冰雪封锁的大陆，目前近99.7%的地形被永久冰雪覆盖，而且有明确证据表明，就在最近的末次盛冰期（LGM），冰盖比现在更厚、范围更广。对末次盛冰期以及整个大陆之前估计的冰盖最大值进行的冰盖建模，为这样一个概念提供了广泛支持，即如果不是全部，那么大部分目前无冰的地面在之前的冰川作用期间都曾被冰盖覆盖。这导致了一种广泛持有的观念，即南极洲所有中生代（冰川作用前）的陆地生命都被连续且不断加深的冰川事件消灭了。这种破坏的隐含结论是，大多数（可能是全部）当代陆地生命是在随后的冰川消退期殖民该大陆的。然而，最近出现的几条相互补充的生物学和地质学研究线索，无法与当前对南极冰川历史的重建轻松协调，因此对现有范式提出了根本性挑战。在这里，我们总结并综合了这些研究领域的证据。新出现的基本见解证实，当代南极陆地生物群的大量元素在数百万年甚至冈瓦纳大陆解体前的时间尺度上一直在原地持续隔离。这种新的、复杂的南极陆地生物地理学与最近的研究工作相呼应，表明环南极海洋动物群的区域化和进化隔离程度比以前认为的更高。这些发现既需要在南极洲采用一种新的生物学范式，也对当前对南极冰川历史的理解提出了挑战。这对我们理解南极洲在地球系统中的关键作用具有重大意义。
