Carbon trace gases in lake and beaver pond ice near Thompson, Manitoba, Canada

Beaver pond biogeochemical effects in the Maryland Coastal Plain

The fluxes and concentrations of materials from two contiguous second-order watersheds in the Coastal Plain of Maryland, U.S.A. were measured for six years prior to and six years subsequent to the formation of a 1.25 ha beaver pond near the bottom of one of the watersheds. The watersheds have a clay aquiclude and were equipped with V-notch weirs and continuous volume-integrating water samplers....

Gases in ice cores.

Air trapped in glacial ice offers a means of reconstructing variations in the concentrations of atmospheric gases over time scales ranging from anthropogenic (last 200 yr) to glacial/interglacial (hundreds of thousands of years). In this paper, we review the glaciological processes by which air is trapped in the ice and discuss processes that fractionate gases in ice cores relative to the conte...

The beaver pond analogy of blood glucose control.

The concentration of glucose is tightly regulated in the blood by a complicated set of physiological variables. To provide students with a means to more readily understand these complex mechanisms, the control of the water level in a beaver pond is presented as an analogy. A beaver must maintain a constant water level in the pond for the proper functioning of the lodge, just as blood glucose is...

The Age of the Lake Saint Martin Impact Structure (manitoba, Canada)

Noble Gases in Tagish Lake

Introduction: Tagish Lake has been classified as a CI2 chondrite [1] with an interstellar grain abundance enhanced over that of CI1 and CM2 chondrites [2]. Noble gases have been used as markers for the presence of exotic, presolar grains in chondritic meteorites: Xe-HL (nanodiamonds) and Xe-s/Ne-E (SiC). We have measured He, Ne, Ar and Xe in whole-rock Tagish Lake, and an orthophosphoric acidre...