Cowles Timothy J.

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Timothy J.

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  • Technical Report
    Copepods from warm-core ring 82-H
    (Woods Hole Oceanographic Institution, 1989-07) Copley, Nancy J. ; Wiebe, Peter H. ; Cowles, Timothy J.
    Net tows were collected with a Multiple Opening/Closing Net Environmental Sampling System (MOCNESS) carrying twenty 1-m2 nets in October 1982 in and near warm-core ring 82-H in the North Atlantic (RV/Knorr cruise 98). This report includes the species list and abundance tables of the copepods found in five of the tows. There are four types of abundance tables: raw data, standardized to #/1000 m3 , integrated #/m2 to 1000 m depth, and cumulative percents over the depth of the tows.
  • Working Paper
    Interdisciplinary study of warm core ring physics, chemistry, and biology
    (Woods Hole Oceanographic Institution, 1981-03) Kester, Dana R. ; Flierl, Glenn R. ; McCarthy, James J. ; Schink, David R. ; Wiebe, Peter H. ; Joyce, Terrence M. ; Backus, Richard H. ; Cowles, Timothy J.
    We are conducting an interdisciplinary study of the structure and dynamics of Gulf Stream \Warm Core Rings by a time series investigation of selected rings. This program consists of highly integrated components which include physical, chemical, and biological investigation and modeling studies. These components are designed to provide information on the structure of rings and exchange mechanisms at ring boundaries, on their marine chemistry, and on the environmental controls of biological activity of selected constituents associated with Warm Core Rings. This research is being conducted by approximately two dozen investigators from thirteen marine institutions. An interdisciplinary program of the scope proposed is required in order to understand the interdependence among biological, chemical, and physical processes in the ocean. This study of the structure and evolution of Warm Core Rings will enhance the understanding of fundamental oceanic processes and the role of rings in the region where they occur.
  • Preprint
    Physical and biological variables affecting seabird distributions during the upwelling season of the northern California Current
    ( 2004-08-28) Ainley, David G. ; Spear, Larry B. ; Tynan, Cynthia T. ; Barth, John A. ; Pierce, Stephen D. ; Ford, R. Glenn ; Cowles, Timothy J.
    As a part of the GLOBEC-Northeast Pacific project, we investigated variation in the abundance of marine birds in the context of biological and physical habitat conditions in the northern portion of the California Current System (CCS) during cruises during the upwelling season 2000. Continuous surveys of seabirds were conducted simultaneously in June (onset of upwelling) and August (mature phase of upwelling) with ocean properties quantified using a towed, undulating vehicle and a multi-frequency bioacoustic instrument (38-420 kHz). Twelve species of seabirds contributed 99% of the total community density and biomass. Species composition and densities were similar to those recorded elsewhere in the CCS during earlier studies of the upwelling season. At a scale of 2-4 km, physical and biological oceanographic variables explained an average of 25% of the variation in the distributions and abundance of the 12 species. The most important explanatory variables (among 14 initially included in each multiple regression model) were distance to upwelling-derived frontal features (center and edge of coastal jet, and an abrupt, inshore temperature gradient), sea-surface salinity, acoustic backscatter representing various sizes of prey (smaller seabird species were associated with smaller prey and the reverse for larger seabird species), and chlorophyll concentration. We discuss the importance of these variables in the context of what factors may be that seabirds use to find food. The high seabird density in the Heceta Bank and Cape Blanco areas indicate them to be refuges contrasting the low seabird densities currently found in most other parts of the CCS, following decline during the recent warm regime of the Pacific Decadal Oscillation.