Table of Contents

• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Program Information
• Funding

HPLC measured pigments, samples drawn from "TM" Primary Production casts.

   PI:                Robert R. Bidigare
   of:                University of Hawaii
   dataset:           Pigments, HPLC method, sampled from TM casts
   dates:             March 17, 1995 to April 07, 1995
   location:          N: 19.883  S: 9.9988  W: 58.0035  E: 68.7474
   project/cruise:    Arabian Sea/TTN-045; Process cruise 2 (Spring Intermonsoon)
   ship:              R/V Thomas Thompson
 
 

HPLC Pigment methods

Method by Wright et al (Mar. Ecol. Prog. Ser. 1991, 77:183-196) CHLA1, CHLA2, CHLB1 and CHLB2 estimated following the method of Latasa et al (Mar. Chem. 1996, 51:315-324)


Pigment data for P2 & P5:

A comparison of the TURNER-determined chlorophyll a concentrations with the
HPLC-determined TOTCHLA concentrations (monovinyl chlorophyll a + divinyl
chlorophyll a + monovinyl chlorophyllide a;  units = ng Chl a
equivalents/L) was performed for Process Cruise #2 (TTN-045) and Process
Cruise #5 (TTN-050).  While good correlations were obtained for both
cruises, the slope obtained for Process Cruise #5 was significantly
different from 1 (i.e., TURNER > HPLC).  This difference was probably
caused by the presence of Chl a-related pigments during Process Cruise #5.
Thus, we recommend that whenever possible use the HPLC pigment data and not
the TURNER pigment data.  If HPLC data is not available for a given cast,
we further recommend that you use the following equations to transform the
TURNER data into HPLC-equivalent concentrations (cf., Babin, M., A. Morel,
H. Claustre, A. Bricaud, Z. Kolber and P.G. Falkowski.  1996.  Nitrogen-
and irradiance-dependent variations of the maximum quantum yield of carbon
fixation in eutrophic, mesotrophic and oligotrophic marine systems.
Deep-Sea Research, in press).

Results of geometric mean regression analyses (reduced major axis):

Y = HPLC TOTCHLA (monovinyl chlorophyll a + divinyl chlorophyll a +
monovinyl chlorophyllide a), units = ng Chl a equivalents/L

X = TURNER chlorophyll a (it is necessary to convert the Turner Chl a
concentrations in the Arabian Sea data base from mg/m3 to ng/L by
multiplying concentrations by 1000)

(1) Process Cruise #2 (TTN-045)

HPLC TOTCHLA = TURNER*(0.975) + 4.833 (r = 0.9822, n = 146)

(2) Process Cruise #5 (TTN-050)

HPLC TOTCHLA = TURNER*(0.708) + 12.881 (r = 0.9772, n = 575)


Robert R. Bidigare
Department of Oceanography
University of Hawaii
Honolulu, HI  96822
808-956-6567 (voice mail)
808-956-9516 (fax)

The U.S. Arabian Sea Expedition which began in September 1994 and ended in January 1996, had three major components: a U.S. JGOFS Process Study, supported by the National Science Foundation (NSF); Forced Upper Ocean Dynamics, an Office of Naval Research (ONR) initiative; and shipboard and aircraft measurements supported by the National Aeronautics and Space Administration (NASA). The Expedition consisted of 17 cruises aboard the R/V Thomas Thompson, year-long moored deployments of five instrumented surface buoys and five sediment-trap arrays, aircraft overflights and satellite observations. Of the seventeen ship cruises, six were allocated to repeat process survey cruises, four to SeaSoar mapping cruises, six to mooring and benthic work, and a single calibration cruise which was essentially conducted in transit to the Arabian Sea.

The United States Joint Global Ocean Flux Study was a national component of international JGOFS and an integral part of global climate change research.

The U.S. launched the Joint Global Ocean Flux Study (JGOFS) in the late 1980s to study the ocean carbon cycle. An ambitious goal was set to understand the controls on the concentrations and fluxes of carbon and associated nutrients in the ocean. A new field of ocean biogeochemistry emerged with an emphasis on quality measurements of carbon system parameters and interdisciplinary field studies of the biological, chemical and physical process which control the ocean carbon cycle. As we studied ocean biogeochemistry, we learned that our simple views of carbon uptake and transport were severely limited, and a new "wave" of ocean science was born. U.S. JGOFS has been supported primarily by the U.S. National Science Foundation in collaboration with the National Oceanic and Atmospheric Administration, the National Aeronautics and Space Administration, the Department of Energy and the Office of Naval Research. U.S. JGOFS, ended in 2005 with the conclusion of the Synthesis and Modeling Project (SMP).