Browsing Cullen, John by Title
Now showing items 15-34 of 37
-
Mapping coastal optical and biogeochemical variability using an autonomous underwater vehicle and a new bio-optical inversion algorithm
Autonomous underwater vehicles (AUVs) can map water conditions at high spatial ( horizontal and vertical) and temporal resolution, including under cloudy conditions when satellite and airborne remote sensing are not feasible. ... -
Methyl iodide in the NW Atlantic; spatial and seasonal variation
While the global ocean is an important source of atmospheric methyl iodide (CH (sub 3) I), the major producers of CH (sub 3) I within the ocean remain unclear. During a seasonal study in the NW Atlantic, the relationship ... -
Modeling the effects of ultraviolet radiation on embryos of Calanus finmarchicus and Atlantic cod (Gadus morhua) in a mixing environment
It is well established that ultraviolet radiation (UVR, 280-400 nm) harms aquatic organisms. Reductions in productivity have been reported for phytoplankton, ichthyoplankton, and zooplankton in incubations exposed to UVR. ... -
New algorithms for MODIS sun-induced chlorophyll fluorescence and a comparison with present data products
We discuss important sources of variability in sun-induced chlorophyll fluorescence and examine difficulties in deriving fluorescence data products from satellite imagery, with a focus on the MODerate-resolution Imaging ... -
New production in the warm waters of the Tropical Pacific Ocean
The average depth-integrated rate of new production in the tropical Pacific Ocean was estimated from a calculation of horizontal and vertical nitrate balance over the region enclosed by the climatological 26 degree C ... -
Ocean Fertilization Science, Policy, and Commerce
Over the past 20 years there has been growing interest in the concept of fertilizing the ocean with iron to abate global warming. This interest was catalyzed by basic scientific experiments showing that iron limits primary ... -
Optical detection and assessment of algal blooms
Concerns about harmful algal blooms (HABs) have grown in recent years. There is a pressing need for robust, quantitative, and cost-effective methods to detect and characterize algal blooms. Critical applications of these ... -
Optical detection and assessment of algal blooms
Concerns about harmful algal blooms (HABs) have grown in recent years. There is a pressing need for robust, quantitative, and cost-effective methods to detect and characterize algal blooms. Critical applications of these ... -
-
Photosynthetic characteristics and estimated growth rates indicate grazing is the proximate control of primary production in the Equatorial Pacific
Macronutrients persist in the surface layer of the equatorial Pacific Ocean because the production of phytoplankton is limited. Measurements of photosynthesis as a function of irradiance (P-I) provide information on the ... -
Phytoplankton Growth and Light-Absorption as Regulated by Light, Temperature, and Nutrients
Numerous studies of the growth of phytoplankton in the laboratory have demonstrated the dependence of cellular pigment concentration and growth rate upon light intensity, photoperiod, temperature, and nutrient supply. These ... -
Predicting and verifying the intended and unintended consequences of large-scale ocean iron fertilization
Ocean iron fertilization (OIF) is being considered as a strategy for mitigating rising atmospheric CO2 concentrations. One model for implementation is the sale of carbon offsets. Modeling studies predict that OIF has the ... -
Primary production by suspended and benthic microalgae in a turbid estuary: Time-scales of variability in San Antonio Bay, Texas
The within-day, between-day and month-to-month variability of light attenuation and microalgal chlorophyll a (chl a) and photosynthetic response was measured in San Antonio Bay, Texas, USA. Waters were shallow (<2 m) ... -
Primary Production Estimates from Recordings of Solar Stimulated Fluorescence in the Equatorial Pacific at 150-Degrees-W
Biological, optical, and hydrographical data were collected on the WEC88 cruise along 150-degrees-W and during a 6-day time series station on the equator during February/March 1988. This area was characterized by a subsurface ... -
Relationships between vertical mixing and photoadaptation of phytoplankton: Similarity criteria
In their natural environment phytoplankton are exposed to fluctuations in incident irradiance due to vertical displacements in the water column induced by turbulent fluid motion. A reaction-diffusion model is analyzed to ... -
Retrieval of phytoplankton biomass from simultaneous inversion of reflectance, the diffuse attenuation coefficient, and Sun-induced fluorescence in coastal waters
[1] A model has been developed to retrieve phytoplankton absorption, a proxy for phytoplankton biomass, from observations of reflectance ( R) and the diffuse attenuation coefficient (K-d) collected by moored radiometers ... -
A semi-analytical model of the influence of phytoplankton community structure on the relationship between light attenuation and ocean color
A model was developed to examine the influence of phytoplankton community structure on the relationship between diffuse attenuation and ratios of upwelling radiance. Shifts in phytoplankton communities were represented by ... -
The spectral effects of clouds on solar irradiance
Knowledge of the spectral attenuation associated with clouds is important for accurate estimates of natural irradiance at the Earth's surface. We compare spectral measurements of visible downwelling irradiance, under varying ... -
Spectrally weighted transparency in models of water-column photosynthesis and photoinhibition by ultraviolet radiation
We present a simple method for describing the influence of variable attenuation of spectral irradiance, Kd(lambda), on water-column photosynthesis and its inhibition by ultraviolet radiation (UV). The approach is based on ...
