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USGS CMG 2010-051-FA Metadata

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ID 2010-051-FA
Also Known As M-51-10-GA
2010-051-FA
Abstract United States Geological Survey, Woods Hole, Massachusetts. Chief Scientists: John Crusius, Rob Campbell, Prince William Sound Science Center, Cordova, AK. Sampling; data of field activity 2010-051-FA (M-51-10-GA) in Copper River region, Gulf of Alaska, Alaska, United States, North America, North Pacific from 07/11/2010 to 08/05/2010
Organization United States Geological Survey, Woods Hole, Massachusetts
Chief Scientist John Crusius
Rob Campbell
Activity Type Sampling;
Platform Montague
Area of Operation Copper River region, Gulf of Alaska, Alaska, United States, North America, North Pacific, Gulf of Alaska
Bounding Coordinates
60.63010
-147.12891    -143.26172
57.37394
Ports LEAVE Cordova, AK
ARRIVE Cordova, AK
Dates 07/11/2010 (JD 192) to 08/05/2010 (JD 217)
Analog Materials No analog holdings.
Information Specialist
John Crusius
Crew
John Crusius Chief Scientist
Rob Campbell Chief Scientist, Prince William Sound Science Center
Andrew Schroth
Purpose
Trace metal sampling in the Copper River region of the Gulf of Alaska.
Summary
Recent work has suggested that high iron supply may contribute to a northward 
increase in phytoplankton biomass along the U.S. west coast, consistent with 
'bottom-up' control of these coastal ecosystems.
We examined this hypothesis in waters of the Copper River plume and nearby 
continental shelf in the northern Gulf of Alaska.  These are the first data we 
know of examining 'bottom up'
control of this coastal ecosystem by the supply of nitrate and iron.  These are 
also the first data we know of examining seasonal variability in the mechanisms 
that supply iron to this region, and in the iron concentrations.
Cruises were carried out in early April (late winter conditions), early May 
(peak bloom conditions) and late July (peak river discharge).
Sampling consisted in each case of bottle and CTD casts at five stations, and 
continuous surface-water sampling.
High concentrations (several hundred nM) of 'total dissolveable' Fe (unfiltered, 
pH ~2) were present in surface-waters spanning the continental shelf in
early April 2010, from resuspension of fine glacial flour.  Concentrations 
decreased dramatically beyond the shelf break.
This fine particulate matter represents a large source of 'dissolved' Fe to 
these waters.
Surface-water nitrate concentrations were fairly uniform (~15 uM) across the 
entire shelf at this time, due to deep winter mixing.  By late July this shelf 
particulate Fe source is greatly diminished, owing to strong stratification.
Yet there is abundant 'total dissolveable' Fe (several uM) at this time from the 
Copper River plume (largest single freshwater source to the GoA) and lower, 
significant concentrations in the AK coastal current (that reflect the 
cumulative impact of melting glaciers from further south).
By late July this abundant supply of iron in the Copper River vicinity, together 
with strong stratification, lead to complete consumption of surface-water 
nitrate across the entire shelf (and extending tens of km beyond the shelf).
These data are consistent with the idea that high primary productivity in this 
region is fueled by abundant wintertime surface-water nitrate, together with 
iron supply from fine, labile, glacier-derived particulate matter from 
seasonally variable sources.
Notes
Days at Sea: 24
 Degree of Certainty: 90%
 Report Date: 2010-06-24
Project Number: GX11LQ00E8KWH00
Funding
USGS BRD Global Change
Got Help? For 2010-051-FA, we would appreciate any information on -- analog materials, contract, days at sea, dive count, equipment used, information to be derived, kms of navigation, national plan, NGDC Info, owner, project, project number, publications, scanned materials, seismic description, station count, station description, submersible, tabulated info.
Type Webpage KMZ Arc         Metadata         WHSC
Metadata data     txt  data  FAQ  xml data
Navigation data nav      
Times   050.times      

2010-051-FA location map of where navigation 

equipment operated

 
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