Index Catalog // ScholarsArchive@OSU

Creator:: Letelier, Ricardo M. and Karl, David M.
Abstract:: The concentrations of filamentous diazotroph Trichodesmium spp., present as free trichomes and in colonial assemblages, were measured at approximately monthly intervals at Stn ALOHA (22°45'N, 158°00'W) between October 1989 and December 1992. The average abundance of filaments in the upper 45 m of the water column was highly variable ranging...
Resource Type:: Article
Full Text:: subtropical North Pacific Ocean Ricardo M. L e t e l i e r l . * , David M. ~ a r l ~ ' co l lege of

Creator:: Letelier, Ricardo M. and Karl, David M.
Abstract:: The potential role of the diazotrophic cyanobacterium Trichodesmium spp. In nitrogen and phosphorus dynamics of the euphotic zone of the North Pacific subtropical gyre was investigated as one component of the Hawaii Ocean Time-series (HOT) program. Experiments were conducted with natural samples collected at Stn ALOHA (22° 45’ N, 158°...
Resource Type:: Article

Creator:: Letelier, Ricardo M., Karl, David M., Abbott, Mark R., and Bidigare, Robert R.
Abstract:: The euphotic zone below the deep chlorophyll maximum layer (DCML) at Station ALOHA (a long-term oligotrophic habitat assessment; 22º45′N, 158º00′W) transects the nearly permanently stratified upper thermocline. Hence, seasonal changes in solar radiation control the balance between photosynthesis and respiration in this lightlimited region. Combining profiles of radiance reflectance, algal...
Resource Type:: Article
Full Text:: Letelier, Ricardo M., David M. Karl, Mark R. Abbott, and Robert R

Creator:: Karl, David M., Hebel, Dale V., Björkman, K., and Letelier, Ricardo M.
Abstract:: Based on a long-term set of observations and measurements at a station in the subtropical North Pacific Ocean, it now appears that contemporaneous rates of primary production in low-nutrient open ocean regions and perhaps in the ocean as a whole may be greater than had been considered in field studies...
Resource Type:: Article
Full Text:: KARL, DAVID M., DALE V. HEBEL, K. BJÖRKMAN, AND R. M. LETELIER

Creator:: Letelier, Ricardo M., Abbott, Mark R., and Karl, David M.
Abstract:: Variability of solar-induced (natural) fluorescence and chlorophyll were measured on scales of hours to weeks in the upper layer of a cyclonic eddy located south of the Antarctic Polar Front using a free-floating drifter. The fluorescence signal was analyzed both in terms of chlorophyll concentration and as an indicator of...
Resource Type:: Article

Creator:: Dore, John E., Church, Matthew J., Karl, David M., Sadler, Daniel W., and Letelier, Ricardo M.
Abstract:: Sustained time series have provided compelling evidence for progressive acidification of the surface oceans through exchange with the growing atmospheric reservoir of carbon dioxide. However, few long-term programs exist, and extrapolation of results from one site to larger oceanic expanses is hampered by the lack of spatial coverage inherent to...
Full Text:: ., Church, M. J., Karl, D. M., Sadler, D. W., & Letelier, R. M. (2014). Paired windward and leeward

Creator:: Böttjer, Daniela, Karl, David M., Letelier, Ricardo M., Viviani, Donn A., and Church, Matthew J.
Abstract:: We examined short-term (24–72 h) responses of naturally occurringmarine N2 fixing microorganisms (termed diazotrophs) to abrupt increases in the partial pressure of carbon dioxide (pCO2) in seawater during nine incubation experiments conducted between May 2010 and September 2012 at Station ALOHA (A Long-term Oligotrophic Habitat Assessment) (22°45′N, 158°W) in the...
Resource Type:: Article
Full Text:: elevated seawater pCO₂ in the North Pacific Subtropical Gyre Böttjer, D., D. M. Karl, R. M. Letelier, D

Creator:: Dore, John E., Church, Matthew J., Karl, David M., Sadler, Daniel W., and Letelier, Ricardo M.
Abstract:: Sustained time series have provided compelling evidence for progressive acidification of the surface oceans through exchange with the growing atmospheric reservoir of carbon dioxide. However, few long-term programs exist, and extrapolation of results from one site to larger oceanic expanses is hampered by the lack of spatial coverage inherent to...

Creator:: Dore, John E., Church, Matthew J., Karl, David M., Sadler, Daniel W., and Letelier, Ricardo M.
Abstract:: Sustained time series have provided compelling evidence for progressive acidification of the surface oceans through exchange with the growing atmospheric reservoir of carbon dioxide. However, few long-term programs exist, and extrapolation of results from one site to larger oceanic expanses is hampered by the lack of spatial coverage inherent to...
Resource Type:: Article

Creator:: Letelier, Ricardo M., Bidigare, Robert R., Hebel, Dale V., Ondrusek, M., Winn, C. D., and Karl, David M.
Abstract:: Algal chlorophyll and carotenoid distributions were measured periodically in the euphotic zone of Sta. ALOHA (22º45′N, 158º00′W) between February 1989 and October 1991 to document the variability in phytoplankton abundance and composition. The annual mean depth-integrated (O-200 db) concentration of Chl a displayed significant interannual variability. Seasonal patterns in Chl...
Resource Type:: Article
Full Text:: LETELIER, R. M., R. R. BIDIGARE, D. V. HEBEL, M. ONDRUSEK, C. D

ScholarsArchive@OSU