Table of Contents

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

Copepods identified, staged, and enumerated from TT050 (Aug./Sept.) and TT054 (Nov/Dec) in 1995.

Relevant References: 

Drapun, I. and S.L. Smith. 2011. Halocyprid Ostracods of the Arabian Sea Region. Sultan Qaboos University Academic Publication Board, Sultan Qaboos University, Muscat, Sultanate of Oman, 223pp.

Lane, P.V.Z. and S.L. Smith. 1997. United States Joint Global Ocean Flux Study (U.S. JGOFS) Technical Report: Zooplankton biomass in the upper water column of the Arabian Sea in 1994 and 1995. RSMAS Technical Report 97007, Rosenstiel School of Marine and Atmospheric Science, University of Miami Press, Miami, FL, 23pp.

Lane, P.V.Z., S.L. Smith, J. Zaragoza, I. Prusova and M. Roman. 1998. United States Joint Global Ocean Flux Study (U.S. JGOFS) Technical Report: Copepod taxonomy, abundance and biomass in the pper 300 meters of t he Arabian Sea during the Southwest Monsoon (August/September) of 1995. RSMAS Technical Report 98007, Rosenstiel School of Marine and Atmospheric Science, University of Miami Press, Miami, FL, 409pp.

Lane, P.V.Z., S.L. Smith, J. Zaragoza and I. Prusova. 1999. United States Joint Global Ocean Flux Study (U.S. JGOFS) Technical Report: Copepod taxonomy, abundance and biomass in the upper 300 meters of the Arabian Sea during the Northeast Monsoon (December) of 1995. RSMAS Technical Report 99004, Rosenstiel School of Marin eand Atmospheric Science, University of Miami Press, Miami, FL, 306pp.

Prusova, I., S.L. Smith, and E. Popova. 2011. Calanoid Copepods of the Arabian Sea Region. Sultan Qaboos University Academic Publication Board, Sultan Qaboos University, Muscat, Sultanate of Oman, 240pp.

Smith, S.L., L.A. Codispoti, J.M. Morrison and R.T. Barber. 1998. The 1994-1996 Arabian Sea Expedition: an integrated, interdisciplinary investigation of the response of the northwestern Indian Ocean to monsoonal forcing. Deep-Sea Research II, 45, 1905-1916.

Smith, S.L., M. Roman, I Prusova, K. Wishner, M. Gowing, L.A. Codispoti, R. Barber, J. Marra and C. Flagg. 1998. Seasonal response of zooplankton to monsoonal reversals in the Arabian Sea. Deep-Sea Research, 45 (10-11), 2369-2403.

Bongo net. Bongo net collections covering the upper 200 meters were made at all intermediate stations and at some hydrographic stations, but not at the 48-hour time-series stations. Bongo net frames were 60cm diameter and were fitted with 153 and 335um mesh nets. Only the 153um mesh samples were analyzed. General Oceanics model 2030R flow meters were placed in the net mouth openings for the determination of volume filtered. The nets were towed obliquely from the side of the ship at approximately 1.5 to 2 knots (2.8-3.7 km h-1) through the water. Winch speed was generally 30m min-1 during deployment and 20m min-1 during recovery. The net was allowed to settle for about 30 seconds while at maximum wire out. The target depth for all Bongo tows was 200m, unless the sonic depth was less than that, and the wire out was adjusted during each tow, depending on the wire angle, to attain that depth. The maximum sampling depth of each tow was determined from a Wildlife Computers Mk3e Time Depth Recorder (TDR) attached to the net frame. Elapsed sampling time versus depth was plotted from TDR data for representative tows from cruises TN050 (August 18, 1995 - September 15, 1995) and TN 054 (November 30, 1995 - December 29, 1995). These comparisons showed that retrieval of the net was reasonably steady in both monsoon seasons so that all depth intervals were sampled uniformly. In the worst weather (TN 050; SW Monsoon), the rate of vertical ascent of the net was 11m min-1 (+/- 3; n=4), while in the better weather (TN054; NE Monsoon) ascent rate was 14m min-1 (+/-2; N=4).

The samples from the 153um Bongo net were split in a modified Folsom splitter, which split the sample into four parts consisting of 50%, 20%, 20% and 10%. In general, 10% was used for dry weight measurements (Lane and Smith, 1997;), 20% was preserved for collaborating scientists, and 70% was preserved for displacement volume measurements and taxonomic analysis.

Laboratory analysis. The samples reported here were split one to four times, depending on the amount of plankton present, in a Folsom splitter at the Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami. Subsamples were concentrated to 20 to 100ml and were transported to Ukraine (Russia) for enumeration and identification at the Institute for Biology of the Southern Seas (IBSS) in Sevastopol. Treatment of the samples at IBSS depended on the amount of plankton present in each sample. When the sample contained only a small amount of plankton, the entire split was analyzed for all species. In most cases, however, organisms smaller than ~1.5mm were identified and counted in smaller subsamples collected with a 1, 2 or 5ml Stempel pipette. Two replicate subsamples were withdrawn and counted and the data were averaged for calculation of abundance; generally 1-40 individuals per taxon were identified and sometimes more when a taxon was particularly abundant. Organisms ranging in size from ~1-2mm were counted in another part of the subsample collected with a 5ml Stempel pipette or by splitting the subsample into two or four equal parts. The entire subsample originating at RSMAS was then analyzed for abundance of organisms larger than 2mm, including copepods, euphausiids, amphipods, fish larvae, ostracods and any rare, large organisms. A total of 300 to 500 organisms per entire split were identified and counted.  The identifications were performed with the aid of Leningrad Optic-Mechanics Company (LOMO) binocular microscopes using various magnifications depending on the sizes of the individuals being identified. Copepod species are listed in alphabetical order. All copepod adult stages, copepodite stages and nauplii found in each sample are listed. The taxonomic notations are: c1 = copepodite stage I of the species; c2 = copepodite stage II of the species; c3 = copepodite stage III of the species; c4 = copepodite stage IV of the species; c5 = copepodite stage V of the species; c = undetermined copepodite stage of the species; m = adult males of the species; f = adult females of the species. Total length of the copepods is the average length in mm measured microscopically for that taxon.

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 infusion or transport of large-bodied copepods, whose life cycle includes diapauses (hibernation) at subsurface depths, into the upwelling area off Oman is fundamental to the success of the pelagic ecosystem in the region. Changes in the SW Monsoon wind pattern or strength can alter timing and intensity of upwelling and mixing, presenting the possibility that primary productivity during upwelling (dominated by diatoms) and the large-bodied, diapausing copepods that ingest phytoplankton, may become de-coupled. When decoupling has happened in other ecosystems, populations crash forcing a food web reorganization, often with outcomes that are undesirable. In the case of Oman, the abundant myctophid fish, a key link to upper trophic level fish of commercial importance, may be at risk for a significant population decline because of changes in the timing of primary production.

Now that climate change may be altering the monsoon cycle of wind forcing in the Arabian Sea, there exists the possibility that the life cycle of diapausing C. carinatus may become mismatched with the appearance of their food supply occurring during the upwelling season. While ontogenetic migration is generally associated with high latitude environments, where the spring bloom of phytoplankton driven by the annual cycle of sunlight provides a spatially and temporally reliable food supply, there are no other copepods inhabiting the tropics and subtropics that have diapause at depth in their life cycle (except perhaps Subeucalanus crassus in the Arabian Sea). Understanding the cues that trigger downward migration of C. carinatus at the end of the upwelling season, and investigating whether S. crassus has a phenology similar to C. carinatus, are the goals of this project. An international archive of samples from the Arabian Sea extending back to 1992, as well as new samples, will be used in this study.

Affiliated programs: The Netherlands Indian Ocean Programme, NIOP; US-GLOBEC

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).

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).