Early Pleistocene glacial cycles in marine δO exhibit strong obliquity pacing, but there is a perplexing lack of precession variability despite its important influence on summer insolation intensity – the presumed forcing of ice sheet growth and decay according to the Milankovitch hypothesis. This puzzle has been explained in two ways: Northern Hemisphere ice sheets instead respond to insolatio...

Bacterial communities reside in basal ice, sediment, and meltwater in the supra-, sub-, and proglacial environments of John Evans Glacier, Nunavut, Canada. We examined whether the subglacial bacterial community shares common members with the pro- and supraglacial communities, and by inference, whether it could be derived from communities in either of these environments (e.g., by ice overriding ...

Strandings of marine animals are relatively common in marine systems. However, the underlying mechanisms are poorly understood. We observed mass strandings of krill in Antarctica that appeared to be linked to the presence of glacial meltwater. Climate-induced glacial meltwater leads to an increased occurrence of suspended particles in the sea, which is known to affect the physiology of aquatic ...

Increased mass losses from the Greenland ice sheet and inferred contributions to sea-level rise have heightened the need for hydrologic observations of meltwater exiting the ice sheet. We explore whether temporal variations in ice-sheet surface hydrology can be linked to the development of a downstream sediment plume in Kangerlussuaq Fjord by comparing: (1) plume area and suspended sediment con...

[1] It is generally accepted that surface freshwater anomalies in the Southern Ocean drive increases in North Atlantic Deep Water (NADW) formation via a bipolar density see-saw. We find that a Southern Ocean freshwater pulse of comparable magnitude to meltwater pulse 1A, shuts down, instead of strengthens, NADW in a glacial climate simulation. Unlike the modern-day simulation, the glacial exper...

We explore potential changes in Greenland ice sheet form and flow associated with increasing ice temperatures and relaxing effective ice viscosities. We define "thermal-viscous collapse" as a transition from the polythermal ice sheet temperature distribution characteristic of the Holocene to temperate ice at the pressure melting point and associated lower viscosities. The conceptual model of th...

35 36 New high resolution multibeam data in the Gulf of Bothnia reveal for the first time the 37 subglacial environment of a Bothnian Sea Ice Stream. The geomorphological record suggests 38 that increased meltwater production may have been important in driving rapid retreat of 39 Bothnian Sea ice during deglaciation. Here we apply a well-established one-dimensional 40 flowline model to simulate...

Article Outline Glossary Definition of the Subject Introduction Several full numbered sections Future Directions Bibliography Glossary Ablation. Snow and ice removed from an ice mass via meltwater runoff, sublimation, wind scour, or glacial calving (mechanical fracturing and separation). Accretion. Increase in ice mass by basal growth in the case of floating ice, the compression of snow into ic...

Small changes in the availability of liquid water can have profound effects on the water levels, aqueous chemistry and biogeochemical dynamics of the closed-basin, perennially ice-covered lakes of the McMurdo Dry Valleys, Antarctica. We have compiled the published and unpublished data on dissolved gas, tritium and chlorofluorocarbons (CFCs) for Lake Fryxell and Lake Hoare to determine the effec...

Different sea surface temperature (SST) reconstructions for the Last Glacial Maximum are applied to a hybrid-coupled climate model. The resulting oceanic states are perturbed by North Atlantic meltwater inputs in order to simulate the effect of Heinrich Events on the Atlantic thermohaline circulation (THC) and SST. The experiments show that both the Atlantic SST signature of the meltwater event...