1994 Arctic Ocean Section
lated with macrofaunal abundance, as were sediment
remineralization rates. Given that the surface waters
appeared to be capable of consuming all food being
produced during the cruise, this result is surprising.
It argues that the food supporting the benthos must
be reaching the bottom during the early part of the
summer. We will only be able to test this hypothesis
by being in the Arctic during the early summer.
As a subset of our major question we hypothe-
sized that benthic biomass and processes would
decline from a maximum in the Chukchi Sea to a
minimum under the permanent ice pack and then
begin to increase again towards the more productive
marginal ice zone north of Fram Strait. Instead, we
found that macrofaunal biomass and mixing pro-
cesses were typically higher in the Amerasia Basin
than in the Eurasia Basin. We are developing a rela-
tionship between benthic micro- and macrofaunal
biomass and the flux of particles to the bottom of
the ocean for other regions of the Arctic (in collabor-
ation with Jody Deming of the University of Wash-
ington). We hope to be able to use our AOS-94 benthic data to calculate
Lisa Clough prepar-
ing a mud sample
particulate flux along the AOS-94 transect (a measurement that was not pos-
on the Polar Sea.
sible during the cruise).
Our analyses of sediment characteristics support the patterns discussed
above. As expected, the depth of the water column above the bottom also
appeared to have an effect on the simple Amerasia versus Eurasia pattern de-
scribed above. Samples collected from both the Mendeleyev and Lomonosov
Ridges contain more chlorophyll, phaeopigments (breakdown products of chlo-
rophyll) and total carbon than samples collected from deeper depths, even if
the deeper stations were collected nearer to the Alaskan Shelf.
When we combine and compare the estimates of water column productiv-
ity, particle flux, gradient-driven sedimentary oxygen flux and sedimentary
carbon burial, we will be able to determine both the degree of pelagic/benthic
coupling in the Arctic Ocean and the role that the benthic animals play in
carbon cycling in the present-day Arctic. Interpreting biological modification
of stratigraphic and pore-water profiles will be critical in determining the present
state of carbon preservation, as well as in understanding the history of the
Arctic Ocean (in conjunction with the researchers studying the geology of the
Arctic Ocean Basin).
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