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Recent Contributions: L.J. Plug and J.J. West. (in press). Thaw lake expansion in a
two-dimensional coupled model of heat transfer, thaw subsidence and mass movement.
Journal of Geophysical Research. West, J. J., and L. J. Plug (2008), Time-dependent morphology
of thaw lakes and L.J. Plug, C. Walls and B.M. Scott, 2008, Tundra lake
changes from L.J. Plug and B.T. Werner 2008. Modelling of ice-wedge
networks. Permafrost and Periglacial
Processes. doi:10.1002/ppp.604 L.J. Plug, J.C. Gosse, J.M. McIntosh and R. Bigley, 2007.
Attenuation of cosmic rays in temperate forest. Journal of Geophysical
Research, 112, F02022, doi:10.1029/2006JF000668 [pdf] This
is
Plug, Lab Boss and Chief Disorganizer, as of summer 07: Other
people here now or recently, and their current location (these are
mostly students, and they've done most of the work):
Current projects with links to further reading.... Forests and cosmic
rays Forests intercept cosmic rays
that bombard Earth. The amount that these rays are intercepted by
forests is of importance to a wide range of geological problems,
especially to cosmogenic nuclide-based geochronology. It
has not been possible to accurately measure the shielding effect of
forests. By developing a computer model of rays through forests, which
uses forestry data to simulate the biomass in trees and organic litter
in 3D, we show
that forests can intercept more cosmic rays than previously thought. We
test the differences in shielding between locations within a forest,
and the differences between sparse Acadian (Nova Scotian) forest and
dense coastal rainforest. L.J. Plug, J.C. Gosse, J.M. McIntosh and R. Bigley, 2007.
Attenuation of cosmic rays in temperate forest. Journal of Geophysical
Research, 112, F02022, doi:10.1029/2006JF000668 [pdf] Forests,
harvesting, and erosion How does the species and age structure of a forest change over
periods of 100s to 1000s of years? What impact do human
management strategies have on forest dynamics, and how does this impact
compare to the effects of natural disturbances? Over what
timescale is a "sustainable" harvesting strategy truly sustainable, and
how sensitive is this timescale to climate change? Are there
patterns in the distributions of species through space and time?
We've been involved in
work on forests in Interior Alaska, and found that there is significant
transere succession (a slow drift in the properties of a forest over
multiple cycles of secondary succession, in this case through recurring
disturbances caused by fire). More recently, our geographic focus has
changed to Nova Scotia. We've used a modeling approach to
investigate the impacts of human-caused disturbances on forest
dynamics. Niina Luus (an Environmental Science student) and Plug are
building a forest simulator which combines ecological processes of seed
dispersal, inter-species competition and mortality with erosion and
natural disturbances (fire, wind gales, spruce budworm). The
model also includes various management practices such as clear-cutting,
selective logging, and road construction. We are currently validating
this model, and will later experiment with different management
practices. Mann, D., and L. Plug (1999), Primary succession in upland Alaskan taiga: Development of a fire-organized system of clonal vegetation, soils and fire., Ecoscience, 6, 272-285 N. Luus, 2007. Modelling the long-term (>100y)
implications of Thaw lakes in
permafrost
and climate change Thaw lakes are lakes that initiate and grow by the thawing and
collapse of ice-rich permafrost beneath and around their margins. They
occur
across more than 1 million km^2 of northern Canada, Alaska and Siberia
-- areas where climate warming has been especially rapid over the past
few decades. The lakes can release greenhouse gases, methane and
carbon-dioxide, to the atmosphere if the thawing permafrost contains
old plant material which decomposes in lakes. The release of
these greenhouse gases may be a positive feedback to warming. West, J. J., and L. J. Plug (2008), Time-dependent morphology
of thaw lakes and L.J. Plug, C. Walls and B.M. Scott, 2008, Tundra lake
changes from L.J. Plug and J.J. West. 2008. Thaw lake expansion in a
two-dimensional coupled model of heat transfer and mass movement.
Journal of Geophysical Research. In press. Fracture
networks L.J. Plug and B.T. Werner, 2002. Nonlinear dynamics of ice-wedge networks and resulting sensitivity to severe cooling events. Nature 17, 9, 929-933. [pdf] L.J. Plug and B.T. Werner, 2001. Fracture networks in frozen
ground. Journal of Geophysical Research 106, 8599-8613. [pdf] Our 2002 'Nonlinear dynamics...' paper provoked a discussion
paper (Burn, 2004) which was published in a different journal. In our
view, that discussion paper presented a
profound misinterpretation of our conclusions. Surprisingly the journal
did not give us an opportunity to reply concurrently (contrary to
conventions in academic publishing), nor publish the reply we submitted
in 2005. In 2007, a version of the reply was finally
accepted. Our 2005 version (which I believe is the more useful)
is
available below. For the as-published version, please check with the
journal. L.J. Plug and B.T. Werner 2005. Confluence of internal
dynamics L.J. Plug and B.T. Werner 2008. Modelling of ice-wedge
networks. Permafrost and Periglacial
Processes. doi:10.1002/ppp.604 CO2
footprint of science-related travel (old stuff, from 2003) How much CO2 do earth and atmospheric scientists
release through air travel to a single professional conference? How
does the CO2 emission by one typical conference-goer compare to the annual CO2 footprint of
most individuals on the planet? We (B. Scott and Plug) were interested
to find out, so we crunched the numbers for the annual
meetings of the American Geophysical Union (which Plug often attends)
and the Ecological Society of America. Here is our abstract and the poster (pdf) with all the
details. |
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Pattern Lab,
Earth Sciences |
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