Physical control of the distributions of a key Arctic copepod in the northeast Chukchi Sea
Physical control of the distributions of a key Arctic copepod in the northeast Chukchi Sea
Date
2015-06
Authors
Elliott, Stephen M.
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DOI
10.1575/1912/7366
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Abstract
The copepod Calanus glacialis is one of the most important zooplankton taxa in the Arctic shelf
seas where it serves as a key grazer, predator, and food source. Its summer distribution and
abundance have direct effects on much of the food web, from blooming phytoplankton to
migrating bowhead whales. The Chukchi Sea represents a highly advective regime dominated
by a barotropicly driven northward flow modulated by wind driven currents that reach the
bottom boundary layer of this shallow environment. In addition, a general northward gradient of
decreasing temperature and food concentration leads to geographically divergent copepod
growth and development rates. The physics of this system establish the connection potential
between specific regions. Unless biological factors are uniform and ideal the true connections
will be an uneven subset of this physically derived connection potential. In August 2012 and
2013, C. glacialis distributions were observed over Hanna Shoal in the northeast Chukchi Sea.
Here we used the Finite Volume Community Ocean Model i-State Configuration Model to
advect these distributions forward and back in time to determine the source and sink regions of
the transient Hanna Shoal C. glacialis population. We found that Hanna Shoal supplies diapause
competent C. glacialis to both the Beaufort Slope and the Chukchi Cap, mainly receives
juveniles from the broad slope between Hanna Shoal and Herald Canyon and receives second
year adults from as far as the Anadyr Gulf and as close as the broad slope between Hanna Shoal
and Herald Canyon. These connection potentials were not sensitive to precise times and
locations of release, but were quite sensitive to depth of release. Deeper particles often traveled
further than shallow particles due to strong vertical shear in the shallow Chukchi. The 2013 sink
region was shifted west relative to the 2012 region and the 2013 adult source region was shifted
north relative to the 2012 region.
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Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2015
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Citation
Elliott, S. M. (2015). Physical control of the distributions of a key Arctic copepod in the northeast Chukchi Sea [Doctoral thesis, Massachusetts Institute of Technology and Woods Hole Oceanographic Institution]. Woods Hole Open Access Server. https://doi.org/10.1575/1912/7366