Obsolete - AFSC/RACE/EcoFOCI: 2011 GOA-IERP & Seward Line 1TX11

1.Conduct tandem 20 cm (153 mesh size) and 60 cm (505 mesh size) Bongo net tows at all grid stations (Table 2) working from west to east. Deployments were made aft from the hydrographic winch, with a Seacat CTD mounted just above the nets to monitor their depth during deployment. Tows were to a maximum of 200 m or 5 b?? 10 m off bottom. 60 cm Net 1 (or side A) bongo sample was immediately preserved for ichthyoplankton. 60 cm Net 2 (or side B) bongo sample was sorted for fish larvae, quantitatively retaining all zooplankton, and then preserved for zooplankton. The sorted fish larvae were placed in 20 ml glass scintillation vials filled with genetic-grade ethanol.

2.Conduct 505 B5m mesh neuston net tows at all grid stations. Deployment was made starboard from the mid-ship crane.

3.Conduct CTD casts, with bottles triggered for macro-nutrients, chlorophyll a and microzooplankton at a subset of stations. Chlorophyll size-fractionation (20 B5m only) were be done at all stations b?? a replicate subset of macronutrients samples were prefiltered prior to freezing. Size-fractionated chlorophyll was extracted on fresh filters without freezing, while total chlorophyll was frozen for later analysis

4.Primary production incubations and iron measurements originally planned for this cruise could not be conducted due to schedule overlap with the Thompson.

The scientific purpose of the core Seward Line project is to develop an understanding of the response of this marine ecosystem to climate variability which has been ongoing since 1998. In 2011 and 2013 the program has been expanded to survey a greater range of the shelf (Chatham Straight to Kodiak), attempting to understand how cross-shelf exchange influences primary and secondary productivity b?? and ultimately the survival of larval fish. Toward this end an expanded domain on the Gulf of Alaska shelf (Kodiak to PWS) determined the physical-chemical structure, primary production and the distribution and abundance of zooplankton and ichthyoplankton.

This cruise complements overlapping sampling activities by the R/V Thompson in Southeastern Alaska, and additional cruises to be conducted summer through fall over the entire domain. Some of the data will be compared with historical data sets whereas other data sets will be a product of the continuing systematic sampling effort on this shelf. This cruise marks the 15th consecutive spring cruise for the Seward Line long-term observation program (LTOP) sampling in the GOA.

Loaded by batch 3769, 12-05-2012 12:34

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There are no legal restrictions on access to the data. They reside in public domain and can be freely distributed.

User must read and fully comprehend the metadata prior to use. Applications or inferences derived from the data should be carefully considered for accuracy. Data will reside at the Alaska Fisheries Science Center. Acknowledgement of NOAA/NMFS/AFSC, as the source from which these data were obtained in any publications and/or other representations of these, data is suggested.

None

None

See InPort entries 26275, 26373 and 26570.

not machine processed

local and offsite backups

See InPort entries 26275, 26373 and 26570