- Email: [email protected]
Oceanic Ecosystems Comparison Subarctic-Pacific (OECOS): West
ARTICLE IN PRESS Deep-Sea Research II 57 (2010) 1593–1594
Contents lists available at ScienceDirect
Deep-Sea Research II journal homepage: www.elsevier.com/locate/dsr2
Editorial
Oceanic Ecosystems Comparison Subarctic-Pacific (OECOS): West
A proposal for high-frequency, spring-season time-series observations in the Oyashio region of the subarctic Pacific originated in correspondence between Tsutomu Ikeda and Charles Miller. Previous sampling of zooplankton and primary producers had been done in comparatively brief visits at monthly intervals. For mesozooplankton in particular that sampling had not provided sufficient resolution to determine rates of developmental progress during the spring phytoplankton blooms typical of the region. All life-cycle stages of the dominant copepods appeared to peak in abundance on the same sampling date. While understanding of production and growth processes during the spring upswing in production and phytoplankton stocks were incomplete for the Oyashio, the same was true of the high-nitrate, low-chlorophyll (HNLC) regions farther to sea, particularly in the Gulf of Alaska. Iron limitation had been thoroughly established by the SERIES and SEEDS projects promoted by PICES, but the complex interactions among rising phytoplankton growth rates, iron- limitation, microheterotroph control of pico- and nanophytoplankton stocks and trophic-cascade effects from mesozooplankton feeding on microheterotrophs were (and remain) far from understood. Seeking a way to stimulate interest in prolonged highfrequency sampling in these two regions during spring, Ikeda and Miller presented a proposal to PICES in late 2004 and received warm support, including funds (generously supplemented by Oregon State University) to hold an OECOS scientific workshop of both Japanese and North American participants at Corvallis, Oregon, USA in May of 2005. General plans were laid out at that workshop for expeditions to examine aspects of the trophicdynamics in both the Oyashio and the Station P area of the Gulf Alaska (Miller and Ikeda, 2006). Participants from Japan were to carry out the Oyashio work; North American participants would work in the HNLC oceanic sector to the east. The U.S. and Canadian OECOS-East scientists prepared a proposal to the U.S. National Science Foundation, which was declined without encouragement to resubmit. With regret they simply gave up. In Japan OECOS-West scientists prepared a proposal for an R.V. Hakuho-Maru cruise in April-May 2007, which was adopted. The regular research cruise in March 2007 of T.V. Oshoro-Maru of Hokkaido University was also assigned as part of OECOS-West research. For detailed planning of a spring campaign in the Oyashio region, OECOS-West convened another
0967-0645/$ - see front matter & 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.dsr2.2010.03.003
workshop at the Ocean Research Institute of Tokyo University in December 2005. Meanwhile, OECOS-West proposals to the Japan Society for the Promotion of Science (JSPS) were prepared and submitted, but ended without success. The lack of funding as a group was not a serious problem, since individual OECOSWest participants had sufficient resources to proceed with the project. The OECOS-West study took place as two cruises on OshoroMaru and Hakuho-Maru that occupied a station (A5) on a line that had been the site of a long-term monthly survey, the A-line. From 8 to 15 March, 2007, the program was initiated with a study of the hydrography, primary production and zooplankton at A5 before the spring bloom of that year. From 5 April to 1 May, 2007, the study resumed, observing features of the ecosystem during the peak of the spring phytoplankton bloom, a bloom dominated by large phytoplankton, predominantly diatoms. As was anticipated might happen, the ecosystem observed at the fixed station was definitely not in a consistent water mass. Rather than being steadily in the cold, low salinity, southbound Oyashio, Station A5 was swept across by varying mixtures of oceanic Oyashio water, coastal Oyashio water and modified Kuroshio water. Thus, the observations of all aspects shifted as the proportions of these water sources varied. Thanks to high-frequency hydrographic observations, the overall variation of ecosystem components can be sorted out and largely assigned to advective and biological processes, including the roles of iron and other nutrients, bacteria, phytoplankton, protozoan and mesozooplankton grazers. The suite of papers in this issue of Deep-Sea Research II is a partial report of results from this extensive exercise in interdisciplinary oceanography, including a paper that places the Oyashio spring bloom of 2007 in a context of spring bloom variations among years. Papers to be published elsewhere will fill in more aspects of the observations. We thank all of the participants in OECOS-West for their interest in the scientific issues, their work at sea and in the laboratory, for preparing the results for publication and for their patience during the editorial process. We extend our thanks to PICES, particularly to Alex Bychkov and Skip McKinnell, for enthusiastic promotion of the project, to the University of Hokkaido and Tokyo University for generous assignment of ship time to OECOS and to the home institutes of all of the participants for supporting their research on the Oyashio spring bloom.
ARTICLE IN PRESS 1594
Editorial / Deep-Sea Research II 57 (2010) 1593–1594
Reference Miller, C.B., Ikeda, T. (Eds.), 2006. Report of the 2005 Workshop on Ocean Ecodynamics Comparison in the Subarctic Pacific. PICES Scientific Report No. 32, 103 pp.
Charles B. Miller n College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331-5503, USA E-mail address: [email protected] Received 15 March 2010; accepted 15 March 2010
Tsutomu Ikeda, Atsushi Yamaguchi Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minatomachi, Hakodate, Hokkaido, Japan
n
Corresponding author.
Contents lists available at ScienceDirect
Deep-Sea Research II journal homepage: www.elsevier.com/locate/dsr2
Editorial
Oceanic Ecosystems Comparison Subarctic-Pacific (OECOS): West
A proposal for high-frequency, spring-season time-series observations in the Oyashio region of the subarctic Pacific originated in correspondence between Tsutomu Ikeda and Charles Miller. Previous sampling of zooplankton and primary producers had been done in comparatively brief visits at monthly intervals. For mesozooplankton in particular that sampling had not provided sufficient resolution to determine rates of developmental progress during the spring phytoplankton blooms typical of the region. All life-cycle stages of the dominant copepods appeared to peak in abundance on the same sampling date. While understanding of production and growth processes during the spring upswing in production and phytoplankton stocks were incomplete for the Oyashio, the same was true of the high-nitrate, low-chlorophyll (HNLC) regions farther to sea, particularly in the Gulf of Alaska. Iron limitation had been thoroughly established by the SERIES and SEEDS projects promoted by PICES, but the complex interactions among rising phytoplankton growth rates, iron- limitation, microheterotroph control of pico- and nanophytoplankton stocks and trophic-cascade effects from mesozooplankton feeding on microheterotrophs were (and remain) far from understood. Seeking a way to stimulate interest in prolonged highfrequency sampling in these two regions during spring, Ikeda and Miller presented a proposal to PICES in late 2004 and received warm support, including funds (generously supplemented by Oregon State University) to hold an OECOS scientific workshop of both Japanese and North American participants at Corvallis, Oregon, USA in May of 2005. General plans were laid out at that workshop for expeditions to examine aspects of the trophicdynamics in both the Oyashio and the Station P area of the Gulf Alaska (Miller and Ikeda, 2006). Participants from Japan were to carry out the Oyashio work; North American participants would work in the HNLC oceanic sector to the east. The U.S. and Canadian OECOS-East scientists prepared a proposal to the U.S. National Science Foundation, which was declined without encouragement to resubmit. With regret they simply gave up. In Japan OECOS-West scientists prepared a proposal for an R.V. Hakuho-Maru cruise in April-May 2007, which was adopted. The regular research cruise in March 2007 of T.V. Oshoro-Maru of Hokkaido University was also assigned as part of OECOS-West research. For detailed planning of a spring campaign in the Oyashio region, OECOS-West convened another
0967-0645/$ - see front matter & 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.dsr2.2010.03.003
workshop at the Ocean Research Institute of Tokyo University in December 2005. Meanwhile, OECOS-West proposals to the Japan Society for the Promotion of Science (JSPS) were prepared and submitted, but ended without success. The lack of funding as a group was not a serious problem, since individual OECOSWest participants had sufficient resources to proceed with the project. The OECOS-West study took place as two cruises on OshoroMaru and Hakuho-Maru that occupied a station (A5) on a line that had been the site of a long-term monthly survey, the A-line. From 8 to 15 March, 2007, the program was initiated with a study of the hydrography, primary production and zooplankton at A5 before the spring bloom of that year. From 5 April to 1 May, 2007, the study resumed, observing features of the ecosystem during the peak of the spring phytoplankton bloom, a bloom dominated by large phytoplankton, predominantly diatoms. As was anticipated might happen, the ecosystem observed at the fixed station was definitely not in a consistent water mass. Rather than being steadily in the cold, low salinity, southbound Oyashio, Station A5 was swept across by varying mixtures of oceanic Oyashio water, coastal Oyashio water and modified Kuroshio water. Thus, the observations of all aspects shifted as the proportions of these water sources varied. Thanks to high-frequency hydrographic observations, the overall variation of ecosystem components can be sorted out and largely assigned to advective and biological processes, including the roles of iron and other nutrients, bacteria, phytoplankton, protozoan and mesozooplankton grazers. The suite of papers in this issue of Deep-Sea Research II is a partial report of results from this extensive exercise in interdisciplinary oceanography, including a paper that places the Oyashio spring bloom of 2007 in a context of spring bloom variations among years. Papers to be published elsewhere will fill in more aspects of the observations. We thank all of the participants in OECOS-West for their interest in the scientific issues, their work at sea and in the laboratory, for preparing the results for publication and for their patience during the editorial process. We extend our thanks to PICES, particularly to Alex Bychkov and Skip McKinnell, for enthusiastic promotion of the project, to the University of Hokkaido and Tokyo University for generous assignment of ship time to OECOS and to the home institutes of all of the participants for supporting their research on the Oyashio spring bloom.
ARTICLE IN PRESS 1594
Editorial / Deep-Sea Research II 57 (2010) 1593–1594
Reference Miller, C.B., Ikeda, T. (Eds.), 2006. Report of the 2005 Workshop on Ocean Ecodynamics Comparison in the Subarctic Pacific. PICES Scientific Report No. 32, 103 pp.
Charles B. Miller n College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331-5503, USA E-mail address: [email protected] Received 15 March 2010; accepted 15 March 2010
Tsutomu Ikeda, Atsushi Yamaguchi Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minatomachi, Hakodate, Hokkaido, Japan
n
Corresponding author.