Center for Biofilm Engineering
Abstract:
"Lakes of Antarctica"
09-021
Introduction
The evolutionary history of Antarctic lakes reflects the history of the
continent itself. More than 170 Mya, Antarctica was part of the supercontinent
Gondwana. Over time Gondwana broke apart and Antarctica, as we know it today,
was formed around 25 Mya. During its evolution, the continent underwent numerous
climate shifts. Around 65 Mya, Antarctica still had a tropical to subtropical
climate, complete with an Australasian flora and fauna. Ice first began to
appear around 40 Mya. The opening of the Drake Passage between Antarctica and
South America around 23 Mya resulted in the Antarctic Circumpolar Current, which
effectively isolated the advection of lower latitude warm water to the region,
leading to continent-scale glaciations that now typify Antarctica. The period
between 14.8 and 13.6 Mya (mid Miocene) saw an important change in the landscape
evolution. During this time, the linked climate and-glacial system changed from
one dominated by intermittent fluvial erosion and wet-based glaciation, to one
featuring a largely cold-based ice sheet, with cold-based alpine glaciers in the
hyperarid, cold desert conditions of the Transantarctic Mountains. The last
Antarctic glaciation reached a maximum around 18 000 years ago, a period when
the present ice sheet was much thicker and extended out to the edge of the
continental shelf. The icecaps of offshore islands were similarly more
extensive. These extensive ice sheets retreated during the late Pleistocene and
have remained relatively stable during the current Holocene epoch. As a result
of this temporal evolution, we now see lakes distributed on maritime islands,
along the margins of the continent in ablation regions, and subglacially,
beneath the thick ice sheet. All these lakes reflect, to varying degrees, the
legacy left by past geological and climatological conditions. This article
describes the formation, distribution, and diversity of lakes in selected
regions in Antarctica where focused research efforts have occurred. Although no
subglacial lakes have been sampled directly, we present an overview of what is
known about them,with a focus on Lake Vostok, the largest of these lakes.
Priscu JC, Foreman CM, "Lakes of Antarctica," In: Gene E. Likens, (Editor)
Encyclopedia of Inland Waters 2009; volume 2, pp. 555-566 Oxford: Elsevier
|