Anthropogenic releases of trace gases into the
atmosphere are causing a decrease in stratospheric ozone
concentrations and a subsequent increase in solar
ultraviolet-B (UV-B)(280-320 nm) radiation reaching the
earth's surface. The objective of this study was to
determine the acute effects of enhanced UV-B radiation on
the primary production of...
The Critical Depth Hypothesis formalized by Sverdrup in 1953 posits that
vernal phytoplankton blooms occur when surface mixing shoals to a depth shallower than a
critical depth horizon defining the point where phytoplankton growth exceeds losses. This
hypothesis has since served as a cornerstone in plankton ecology and reflects the...
The ¹⁴C-uptake method is the most common approach employed for estimating primary production in the ocean. Normalizing ¹⁴C-uptake to chlorophyll a and time yields a value termed the assimilation number, which is thought to reflect phytoplankton physiology. It is often assumed that the measured rate of ¹⁴C-uptake is between net...
The fluorescence signal emitted from phytoplankton exposed to natural sunlight has been considered a potentially useful tool to examine phytoplankton physiology from in situ radiometers and satellites, but variability in the fluorescence signal is confounded by non-photochemical quenching (NPQ). This pathway dissipates excitation energy as heat rather than fluorescence. It...
The interactive impact of overstory canopy closure, understory brush control, and simulated white-tailed deer (Odocoileus virginianus Zimmermann) herbivory (i.e., clipping) on growth and survival of underplanted white pine (Pinus strobus L.) seedlings was examined. Clipping was conducted in April 1996 and 1997 at three intensities (control, 0% previous year’s growth...
Since June 2010, the Geostationary Ocean Color Imager (GOCI) has been collecting the first
diurnally resolved satellite ocean measurements. Here GOCI retrievals of phytoplankton chlorophyll
concentration and fluorescence are used to evaluate daily to seasonal changes in photophysiological
properties. We focus on nonphotochemical quenching (NPQ) processes that protect phytoplankton from...
Since June 2010, the Geostationary Ocean Color Imager (GOCI) has been collecting the first
diurnally resolved satellite ocean measurements. Here GOCI retrievals of phytoplankton chlorophyll
concentration and fluorescence are used to evaluate daily to seasonal changes in photophysiological
properties. We focus on nonphotochemical quenching (NPQ) processes that protect phytoplankton from...
Full Text:
phytoplankton
photophysiology
O'Malley, R. T., Behrenfeld, M. J., Westberry, T. K., Milligan, A. J., Shang, S
Eddies can influence biogeochemical cycles through a variety of mechanisms, including the excitation of vertical velocities and the horizontal advection of nutrients and ecosystems, both around the eddy periphery by rotational currents and by the trapping of fluid and subsequent transport by the eddy. In this study, we present an...
Since June 2010, the Geostationary Ocean Color Imager (GOCI) has been collecting the first diurnally resolved satellite ocean measurements. Here GOCI retrievals of phytoplankton chlorophyll concentration and fluorescence are used to evaluate daily to seasonal changes in photophysiological properties. We focus on nonphotochemical quenching (NPQ) processes that protect phytoplankton from...
Reconciling rates of organic carbon export from the euphotic zone with the consumption of organic material in the dark ocean remains one of the major quantitative uncertainties of the ocean carbon cycle. Euphotic zone net community production (NCP) provides one broad constraint on export flux and potential carbon drawdown. However,...
