33 research outputs found
From sea ice to seals: a moored marine ecosystem observatory in the Arctic
Although Arctic marine ecosystems are changing rapidly,
year-round monitoring is currently very limited and presents multiple
challenges unique to this region. The Chukchi Ecosystem Observatory (CEO)
described here uses new sensor technologies to meet needs for continuous,
high-resolution, and year-round observations across all levels of the
ecosystem in the biologically productive and seasonally ice-covered Chukchi
Sea off the northwest coast of Alaska. This mooring array records a broad
suite of variables that facilitate observations, yielding better
understanding of physical, chemical, and biological couplings, phenologies,
and the overall state of this Arctic shelf marine ecosystem. While cold
temperatures and 8 months of sea ice cover present challenging conditions for
the operation of the CEO, this extreme environment also serves as a rigorous
test bed for innovative ecosystem monitoring strategies. Here, we present
data from the 2015–2016 CEO deployments that provide new perspectives on the
seasonal evolution of sea ice, water column structure, and physical
properties, annual cycles in nitrate, dissolved oxygen, phytoplankton blooms,
and export, zooplankton abundance and vertical migration, the occurrence of
Arctic cod, and vocalizations of marine mammals such as bearded seals. These
integrated ecosystem observations are being combined with ship-based
observations and modeling to produce a time series that documents biological
community responses to changing seasonal sea ice and water temperatures while
establishing a scientific basis for ecosystem management.</p
Mesoscale, cyclonic eddies as larval fish habitat along the southeast United States shelf: A Lagrangian description of the zooplankton community
The Charleston Gyre region is characterized by continuous series of cyclonic eddies that propagate northeastwards before decaying or coalescing with the Gulf Stream south of Cape Hatteras, NC, USA. Over 5 d, chlorophyll-a concentration, zooplankton displacement volume, and zooplankton composition and abundance changed as the eddy moved to the northeast. Surface chlorophyll-a concentration decreased, and zooplankton displacement remained unchanged as the eddy propagated. Zooplankton taxa known to be important dietary constituents of larval fish increased in concentration as the eddy propagated. The concurrent decrease in chlorophyll-a concentration and static zooplankton displacement volume can be explained by initial stimulation of chlorophyll-a concentration by upwelling and nutrient enrichment near the eddy core and to possible grazing as zooplankton with short generation times and large clutch sizes increased in concentration. The zooplankton community did not change significantly within the 5 d that the eddy was tracked, and there was no indication of succession. Mesoscale eddies of the region are dynamic habitats as eddies propagate northeastwards at varying speeds within monthly periods. The abundance of zooplankton important to the diets of larval fish indicates that the region can provide important pelagic nursery habitat for larval fish off the southeast coast of the United States. A month of feeding and growth is more than half the larval duration of most fish spawned over the continental shelf of the southeastern United States in winter