A5077736395- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Water Quality Monitoring and Analysis
- Oceanographic and Atmospheric Processes
- Microbial Community Ecology and Physiology
- Atmospheric and Environmental Gas Dynamics
- Arctic and Antarctic ice dynamics
- Aquatic Ecosystems and Phytoplankton Dynamics
- Isotope Analysis in Ecology
- Cryospheric studies and observations
- Marine and fisheries research
- Ocean Acidification Effects and Responses
- Marine and coastal plant biology
- Coral and Marine Ecosystems Studies
- Water Quality Monitoring Technologies
- Climate change and permafrost
- Oil Spill Detection and Mitigation
- Water Quality and Pollution Assessment
- Algal biology and biofuel production
- Marine Toxins and Detection Methods
- Underwater Acoustics Research
- Methane Hydrates and Related Phenomena
- Atmospheric chemistry and aerosols
- Environmental Monitoring and Data Management
- Hydrocarbon exploration and reservoir analysis
Bowdoin College
2014-2024
Woods Hole Oceanographic Institution
2005-2024
United States Geological Survey
2019
New England Water Science Center
2019
University of Maine
2010
Bigelow Laboratory for Ocean Sciences
1999-2008
Dalhousie University
2005
NOAA National Ocean Service
2005
Oceanography Society
2005
Laboratoire d’Océanographie de Villefranche
2005
Dissolved and suspended materials in the ocean modify in‐water light field by absorbing scattering photons. Direct measurement of inherent optical properties individual constituents is difficult since themselves cannot all be separated. A model was developed to resolve situ phytoplankton absorption from a measured total spectrum which includes water, dissolved organics, particulate detritus, phytoplankton. The tested on set spectra obtained productive waters around San Juan Islands,...
Ocean color measured from satellites provides daily global, synoptic views of spectral waterleaving reflectances that can be used to generate estimates marine inherent optical properties (IOPs). These reflectances, namely the ratio upwelled radiances downwelled irradiances, describe light exiting a water mass defines its color. IOPs are absorption and scattering characteristics ocean dissolved particulate constituents. Because their dependence on concentration composition constituents,...
Chlorophyll fluorometers provide the largest in situ global data set for estimating phytoplankton biomass because of their ease use, size, power consumption, and relatively low price. While chlorophyll a (Chl) fluorescence is proxy Chl concentration, hence biomass, there exist large natural variations relationship between extracted concentration. Despite this variability, we present here validation WET Labs Environmental Characterization Optics (ECO) series that suggests factor 2...
An inverse model was developed to extract the absorption and scattering (elastic inelastic) properties of oceanic constituents from surface spectral reflectance measurements. In particular, phytoplankton coefficients, solar‐stimulated chlorophyll a fluorescence spectra, particle backscattering spectra were modeled. The tested on 35 obtained irradiance measurements in optically diverse ocean waters (0.07 25.35 mg m −3 range concentrations). universality demonstrated by accurate estimation...
The concept of phytoplankton functional types has emerged as a useful approach to classifying phytoplankton. It finds many applications in addressing some serious contemporary issues facing science and society. Its use is not without challenges, however. As noted earlier, there no universally-accepted set types, and the used have to be carefully selected suit particular problem being addressed. important that sum total all matches all phytoplankton under consideration. For example, if...
The pigment absorption peak in the red waveband observed phytoplankton and particulate spectra is primarily associated with chlorophyll-a exhibits much lower packaging compared to blue peak. minor contributions signature by accessory pigments can be largely removed computing line height at 676 nm above a linear background between approximately 650 715 nm. determination also effective removing total or colored dissolved organic matter non-algal particles, relatively independent of effects...
Abstract The biodiversity and high productivity of coastal terrestrial aquatic habitats are the foundation for important benefits to human societies around world. These globally distributed need frequent broad systematic assessments, but field surveys only cover a small fraction these areas. Satellite‐based sensors can repeatedly record visible near‐infrared reflectance spectra that contain absorption, scattering, fluorescence signatures functional phytoplankton groups, colored dissolved...
The quantitative filter technique (QFT), whereby particles are concentrated onto glass‐fiber filters and analyzed in a spectrophotometer, is used extensively to estimate the absorption coefficients of aquatic particles. A number empirically derived correction factors (β) have been developed account for amplified optical path length associated with highly scattering filters. Published results inconsistent, β remains largest source uncertainty estimated coefficients. In this study, path‐length...
The optical properties of sea ice exhibit considerable spatial, temporal, and spectral variability. During a field experiment at Barrow, Alaska, we examined the horizontal variability albedo transmittance as well vertical in‐ice radiance. Temporal changes were monitored under cold conditions in April during onset melt June. Physical properties, including structure concentrations particulate dissolved material, measured to provide context for understanding observed horizontal, vertical,...
Abstract Optical sensors have distinct advantages when used in ocean observatories, autonomous platforms, and on vessels of opportunity, because their high-frequency measurements, low power consumption, the numerous established relationships between optical measurements biogeochemical variables. However, issues biofouling instrument stability over time remain complicating factors instruments are periods longer than several days. Here, a method for obtaining calibration-independent spectral...
The goal of the EXport Processes in Ocean from RemoTe Sensing (EXPORTS) field campaign is to develop a predictive understanding export, fate, and carbon cycle impacts global ocean net primary production. To accomplish this goal, observations export flux pathways, plankton community composition, food web processes, optical, physical, biogeochemical (BGC) properties are needed over range ecosystem states. Here we introduce first EXPORTS deployment Station Papa Northeast Pacific during summer...
Monitoring programs for harmful algal blooms (HABs) are currently reactive and provide little or no means advance warning. Given this, the development of forecasting systems would be great use because they could guide traditional monitoring a proactive responding to HABs. Forecasting will require near real‐time observational capabilities hydrodynamic/biological models designed run in forecast mode. These networks must detect over ecologically relevant spatial/ temporal scales. One solution...
We present a method to quantify the uncertainties in in-water constituent absorption and backscattering coefficients obtained from an inversion of remotely sensed reflectance (rrs). first find set positive solutions within given uncertainty range around values inverted rrs. The are then computed based on statistics these solutions. demonstrate calculation algorithm using specific semianalytic model applied both field simulated data set. When associated taken into account, parameters...
A three‐channel excitation (435 nm, 470 and 532 nm) Chlorophyll fluorometer (695 nm emission) was calibrated characterized to improve uncertainty in estimated situ concentrations. Protocols for reducing sensor‐related uncertainties as well environmental‐related were developed. Sensor calibrations performed with thirteen monospecific cultures the laboratory, grown under limiting saturating irradiance, sampled at different growth phases. Resulting calibration slope induced by natural...
We investigated the influences of organic content and mineralogical composition on light absorption by mostly mineral suspended particles in aquatic coastal marine systems. Mass‐specific spectra surface sediments from Louisiana lower Mississippi Atchafalaya rivers were measured with a centered sample‐mount integrating sphere analyzed conjunction carbon (OC), hydrochloric acid— (HCl‐) extractable iron, dithionite‐extractable iron contents. Compositions properties comparable to published...
Abstract. Since 2012, an array of 105 Biogeochemical-Argo (BGC-Argo) floats has been deployed across the world's oceans to assist in filling observational gaps that are required for characterizing open-ocean environments. Profiles biogeochemical (chlorophyll and dissolved organic matter) optical (single-wavelength particulate backscattering, downward irradiance at three wavelengths, photosynthetically available radiation) variables collected upper 1000 m every 1 10 days. The database 9837...
Abstract Ongoing climate change is affecting the concentration, export (flux), and timing of dissolved organic carbon (DOC) exported to Gulf Maine (GoM) through changes in hydrologic regime. DOC was calculated for water years 1950 2013 20 rivers 1930 14 draining GoM. also estimated 21st century based on modeling a previously published study. by using regression model LOADEST fit seasonally adjusted concentration discharge (C‐Q) relations. Our results are an analysis sensitivity conditions...
Abstract In situ chlorophyll fluorometers have been widely employed for more than half a century, and to date, it still remains the most used instrument estimate chlorophyll‐a concentration in field, especially measurements onboard autonomous observation platforms, e.g., Bio‐Argo floats gliders. However, deep waters (> 300 m) of some specific regions, subtropical gyres Black Sea, fluorescence profiles frequently reveal “deep sea red fluorescence” features. line with previous studies...
Estimating the biomass of phytoplankton communities via remote sensing is a key requirement for understanding global ocean ecosystems. Of particular interest carbon associated with diatoms given their unequivocal ecological and biogeochemical roles. Satellite-based algorithms often rely on accessory pigment proxies to define diatom biomass, despite lack validation against independent measurements. We used imaging-in-flow cytometry quantify in western North Atlantic, compared results those...
A reflectance inversion model in presented which particle backscattering is parameterized by the ratio, attenuation and absorption coefficients rather than a hyperbolic function. This parameterization removes spectral constraints yields independent estimates of magnitude slope beam attenuation, have been found to correlate with concentration size distribution, respectively. The component consistent observations Mie models, particularly for environments dominated phytoplankton other strongly...
A recently described unicellular chlorophytic alga isolated from meromictic Mono Lake, California, occupies a niche that spans two environments: the upper oxic mixolimnion and deeper anoxic highly reducing monimolimnion. This organism, Picocystis sp. strain ML, accounts for nearly 25% of primary production during winter bloom more than 50% at other times year. In incubations, it is heavily grazed by brine shrimp, Artemia monica . We assessed growth photosynthetic parameters over broad ranges...
Many technologies show promise for real-time observation of HABs and the oceanographic processes that in large part determine their dynamics.