Ocean Carbon and Biogeochemistry Data System

VERTIGO multi-ship
PI notes for Zooplankton fecal pellet flux data from NBST deployments

05 November 2008: Prepared for OCB data system by Steve Gegg, BCO DMO (WHOI)
from documentation contributed by data set PI.

Original data were contributed by PI as a single multi sheet Excel files:
(ALOHAVertigoPelletFluxWEB.xls)
(K2VertigoPelletFluxWEB.xls)

Contact: Debbie Steinberg (VIMS)
College of William & Mary
P.O. Box 1346
Rt. 1208 Greate Rd.
Gloucester Point, VA 23062-1346 USA
Phone: (804) 684-7838
Fax: (804) 684-7293
debbies@vims.edu
http://www.vims.edu/

Associated Publications:

Wilson, S.E., Steinberg, D.K., Buesseler, K.O., "Changes in fecal pellet characteristics with depth as indicators of zooplankton repackaging of particles in the mesopelagic zone of the subtropical and subarctic North Pacific Ocean". Deep Sea Research II.

published in "Understanding the Ocean's Biological Pump: results from VERTIGO (VERtical Transport In the Global Ocean)",
Guest editors Ken Buesseler and Richard Lampitt
Volume 55, Numbers 14-15, July 2008, ISSN 0967-0645

Sampling and Analytical Protocols

General Methodology

Preserved subsamples of the NBST "ID"sediment trap material from the two sites at all three depths were collected and analyzed via light microscopy. Particles recognizable as fecal pellets were counted, measured and categorized by shape and color. Pellets were placed into four general shape categories: ovoid, cylindrical, spherical, and amorphous. Pellets were categorized into four general color classes: dark brown; light brown; red; and white, transparent, or multi-colored. Fecal pellets were also categorized as intact or broken/degraded yet still recognizable as a pellet and larvacean pellets were also measured and counted. Pellet volume was calculated based on length and width measurements and applying the formula for a sphere, cylinder, or ovoid shape that most closely resembled the pellet shape. Fecal pellet volume was converted to carbon using a conversion factor of 0.08 mg C mm-3. Flux was then calculated using the NBST tube area of 0.0114 m^2 and deployment duration.

Note: Extremely large pellets of the heteropod Carinaria spp. were only found at station ALOHA at 150 m (in all replicates). We excluded heteropod pellet POC contribution in our analyses as we have no reliable estimate of their carbon-to-volume content.

Modifications to Original Data

dulicate data column "pct_broken" deleted
data in "pct_broken" columns determined to be identical prior to deletion

date, lon, lat and ev_code from cruise logs merged with original data
one single multi-ship dataset generated for both KM0414 and RR_K2 data

DMO Note: Used common event number from these data and from logs to determine
sample position, date and event code for zooplankton data
(KM0414 event log)
(RR_K2 event log)