
Collin RoeslerBowdoin College · Department of Earth and Oceanographic Science
Collin Roesler
BSc, MS, PhD
About
110
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Introduction
Additional affiliations
July 2009 - present
September 2007 - July 2009
January 1999 - September 2007
Education
September 1987 - December 1992
September 1985 - August 1987
September 1981 - May 1985
Publications
Publications (110)
Chapter 5: Spectrophotometric measurements of particulate absorption using filter pads.
IOCCG Protocol Series (2018). Inherent Optical Property Measurements and Protocols:
Absorption Coefficient, Neeley, A. R. and Mannino, A. (eds.), IOCCG Ocean Optics and
Biogeochemistry Protocols for Satellite Ocean Colour Sensor Validation, Volume 1.0,
IOCCG, D...
Protocols for measuring particulate absorption on filter pads in a spectrophotometer. Comparison of transmission mode, center-mounted integrating sphere, and transmission-reflectance mode, including uncertainty budget.
In marine ecosystems, most physiological, ecological, or physical processes are size dependent. These include metabolic rates, the uptake of carbon and other nutrients, swimming and sinking velocities, and trophic interactions, which eventually determine the stocks of commercial species, as well as biogeochemical cycles and carbon sequestration. As...
The composition of the marine phytoplankton community has been shown to impact many biogeochemical processes and marine ecosystem services. A variety of methods exist to characterize phytoplankton community composition (PCC), with varying degrees of taxonomic resolution. Accordingly, the resulting PCC determinations are dependent on the method used...
The Southern Ocean (SO) is known for its atypical bio‐optical regime. This complicates the interpretation of proxies measured from satellite and in situ platforms equipped with optical sensors, which occupy an important niche for monitoring the vast and remote SO. A ship‐based field study in concert with time series observations from BioGeoChemical...
Measurements of particulate organic carbon (POC) are critical for understanding the ocean carbon cycle, including biogenic particle formation and removal processes, and for constraining models of carbon cycling at local, regional, and global scales. Despite the importance and ubiquity of POC measurements, discrepancies in methods across platforms a...
The composition of the marine phytoplankton community has been shown to impact many biogeochemical processes and marine ecosystem services. A variety of methods exist to characterize phytoplankton community composition (PCC), with varying degrees of taxonomic resolution. Accordingly, the resulting PCC determinations are dependent on the method used...
Particle size distribution (PSD) is a fundamental property that affects almost every aspect of the marine ecosystem, including ecological trophic interactions and transport of organic matter and trace elements. We measured PSDs using a suite of seven instruments in waters near Ocean Station Papa in the Northeast Pacific Ocean. These instruments and...
Estimating the biomass of phytoplankton communities via remote sensing is a key requirement for understanding global ocean ecosystems. Of particular interest is the carbon associated with diatoms given their unequivocal ecological and biogeochemical roles. Satellite‐based algorithms often rely on accessory pigment proxies to define diatom biomass,...
This study assesses marine community production based on the diel variability of bio-optical properties monitored by two BioGeoChemical-Argo (BGC-Argo) floats. Experiments were conducted in two distinct Mediterranean systems, the northwestern Ligurian Sea and the central Ionian Sea, during summer months. We derived particulate organic carbon (POC)...
Accurate measurements of absorption data are required for the development and validation of inversion algorithms for upcoming hyperspectral ocean color imaging sensors, such as the NASA Phytoplankton, Aerosol, Cloud, and ocean Ecosystem mission. This study aims to provide uncertainty estimates associated with leading approaches to measure hyperspec...
The goal of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field campaign is to develop a predictive understanding of the export, fate, and carbon cycle impacts of global ocean net primary production. To accomplish this goal, observations of export flux pathways, plankton community composition, food web processes, and optical, phys...
This study assesses marine biological production of organic carbon based on the diel variability of bio-optical properties monitored by two BioGeoChemical-Argo (BGC-Argo) floats. Experiments were conducted in two distinct Mediterranean systems, the Northwestern Ligurian Sea and the Central Ionian Sea during summer months. We derived particulate org...
Warm water intrusion into Arctic fjords is increasingly affecting polar ecosystems. This study investigated how Atlantic water intrusion and tidewater glacial melting impacted water mass formation and phytoplankton distribution in Kongsfjorden, Svalbard. Field data were collected over a 2-week period during the height of the melt season in August 2...
Chlorophyll fluorometry is one of the most commonly implemented approaches for estimating phytoplankton biomass in situ, despite documented sources of natural variability and instrumental uncertainty in the relationship between in vivo fluorescence and chlorophyll concentration. A number of strategies are employed to minimize errors and quantify na...
Plain Language Summary
Glacier ice, originating from snowfall, flows off the Antarctic Ice Sheet to float on the ocean as ice shelves. At the front of the ice‐shelf, icebergs break off. They appear bluish‐white, intermediate between the blue of pure ice, and the white of snow, because glacier ice contains numerous bubbles that scatter light. Seawat...
Diatoms dominate global silica production and export production in the ocean; they form the base of productive food webs and fisheries. Thus, a remote sensing algorithm to identify diatoms has great potential to describe ecological and biogeochemical trends and fluctuations in the surface ocean. Despite the importance of detecting diatoms from remo...
The biodiversity and high productivity of coastal terrestrial and aquatic habitats are the foundation for important benefits to human societies around the world. These globally distributed habitats need frequent and broad systematic assessments, but field surveys only cover a small fraction of these areas. Satellite-based sensors can repeatedly rec...
Ocean color measured from satellites provides daily global, synoptic views of spectral water-leaving reflectances that can be used to generate estimates of marine inherent optical properties (IOPs). These reflectances, namely the ratio of spectral upwelled radiances to spectral downwelled irradiances, describe the light exiting a water mass that de...
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 of biogeochemical (chlorophyll and dissolved organic matter) and optical (single-wavelength particulate optical backscattering, d...
Since 2012, an array of 105 Biogeochemical (BGC) Argo floats has been deployed across the world’s oceans to fill the observational gap characterizing most of open-ocean environments. Profiles of biogeochemical (chlorophyll and fluorescent dissolved organic matter) and optical (single-wavelength particulate optical backscattering, downward irradianc...
Chlorophyll fluorometers provide the largest in situ global data set for estimating phytoplankton biomass because of their ease of use, size, power consumption, and relatively low price. While in situ chlorophyll a (Chl) fluorescence is proxy for Chl a concentration, and hence phytoplankton biomass, there exist large natural variations in the relat...
The presented database includes 0-1000 m vertical profiles of bio-optical and biogeochemical variables acquired by autonomous profiling Biogeochemical-Argo (BGC-Argo) floats. Data have been collected between October 2012 and January 2016, around local noon, in several oceanic areas encompassing the diversity of ocean's trophic environments. The dat...
In situ chlorophyll fluorometers have been widely employed for more than half a century, and to date, it still remains the most used instrument to estimate chlorophyll-a concentration in the field, especially for measurements onboard autonomous observation platforms, e.g., Bio-Argo floats and gliders. However, in deep waters (> 300 m) of some speci...
Ongoing climate change is affecting the concentration, export (flux), and timing of dissolved organic carbon (DOC) exported to the Gulf of Maine (GoM) through changes in hydrologic regime. DOC export was calculated for water years 1950 through 2013 for 20 rivers and for water years 1930 through 2013 for 14 rivers draining to the GoM. DOC export was...
A 40-year time series of Secchi depth observations from approximately 25 lakes in Acadia National Park, Maine, USA, evidences large variations in transparency between lakes but relatively little seasonal cycle within lakes. However, there are significant coherent patterns over the time series, suggesting that large-scale processes are responsible....
Coincident with shifting monsoon weather patterns over India, the phytoplankter Noctiluca miliaris has recently been observed to be dominating phytoplankton blooms in the northeastern Arabian Sea during the winter monsoons. Identifying the exact environmental and/or ecological conditions that favor this species has been hampered by the lack of conc...
Introduction: Phytoplankton are the simple single-celled photosynthesizers that live in the ocean and form the base of the food chain. They are extremely crucial to global ecosystems, as they are responsible for around 50% of global primary production (Finkel et al., 2010). Cell size is a basic proxy for physiological rates as well as ecosystem str...
Background The world's oceans serve as one of the largest reservoirs of carbon on earth, responsible for drawing down atmospheric CO 2 and sequestering the carbon into deep ocean sediments. Most of the carbon in the ocean is in the form of dissolved organic matter (DOM) [1]. Dependent upon its specific composition, DOM can range from being refracto...
Ocean reflectance inversion models (ORMs) provide a mechanism for inverting the color of the water observed by a satellite into marine inherent optical properties (IOPs), which can then be used to study phytoplankton community structure. Most ORMs effectively separate the total signal of the collective phytoplankton community from other water colum...
The pigment absorption peak in the red waveband observed in phytoplankton and particulate absorption spectra is primarily associated with chlorophyll-aa and exhibits much lower pigment packaging compared to the blue peak. The minor contributions to the signature by accessory pigments can be largely removed by computing the line height absorption at...
An essential aspect of carbon (C) accounting is the development of methods and technologies for measurement and monitoring of C pools and fluxes. Forest and agricultural systems are key to the C cycle, as they hold and rapidly exchange large amounts of C, and human-influenced dynamics of C in these systems are very large. Wetlands, streams, and riv...
Empirically-based satellite estimates of chlorophyll a [Chl] (e.g. OC3) are an important indicator of phytoplankton biomass. To correctly interpret [Chl] variability, estimates must be accurate and sources of algorithm errors known. While the underlying assumptions of band ratio algorithms such as OC3 have been tacitly hypothesized (i.e. CDOM and p...
We investigated the influences of organic content and mineralogical composition on light absorption by mostly mineral suspended particles in aquatic and coastal marine systems. Mass-specific absorption spectra of suspended particles and surface sediments from coastal Louisiana and the lower Mississippi and Atchafalaya rivers were measured with a ce...
A three-channel excitation (435 nm, 470 nm, and 532 nm) Chlorophyll fluorometer (695 nm emission) was
calibrated and characterized to improve uncertainty in estimated in situ Chlorophyll concentrations. Protocols
for reducing sensor-related uncertainties as well as environmental-related uncertainties were developed. Sensor
calibrations were perform...
A three‐channel excitation (435 nm, 470 nm, and 532 nm) Chlorophyll fluorometer (695 nm emission) was calibrated and characterized to improve uncertainty in estimated in situ Chlorophyll concentrations. Protocols for reducing sensor‐related uncertainties as well as environmental‐related uncertainties were developed. Sensor calibrations were perform...
Optical sensors have distinct advantages when used in ocean observatories, autonomous platforms, and on vessels of opportunity, because of their high-frequency measurements, low power consumption, and the numerous established relationships between optical measurements and biogeochemical variables. However, the issues of biofouling and instrument st...
The optical properties of estuaries can vary considerably with the delivery of
pigmented materials from surrounding watersheds and marine waters. In this study, optical
properties sampled at 158 stations throughout the Long Island Sound (LIS) estuary
between 2004 and 2007 show significant regional variability. Chlorophyll, total suspended
matter, l...
Harpswell Sound and the New Meadows estuary are narrow coastal embayments on the eastern side of Casco Bay, in the Gulf of Maine. Hourly oceanographic data was collected at both locations, including ADCP profiles of current velocity vs. depth. It was found that net circulation in both inlets displays both estuarine and inverse estuarine characteris...
Oceanic primary production plays a critical role in the global carbon cycle. The flux of carbon material from the upper ocean, however, is dependent on the quality and quantity of the carbon biomass produced. In the North Atlantic, large diatom chains dominate the phytoplankton community structure early in the spring bloom and can promote a signifi...
Coastal waters represent the commingling of offshore marine and terrestrial surface source waters and therefore are naturally complex and variable. Our long term goal is to establish observational and modeling approaches to predict sources and scales of variability in the source waters, particularly those related to land use activities in upstream...
The Gulf of Maine Ocean Observing System (GoMOOS) was established in the summer of 2001 as a prototype real-time observing system that now includes eleven solar powered buoys with physical and optical sensors, four shore-based long-range HF radar systems for surface current measurement, operational circulation and wave models, satellite observation...
Coastal waters represent the commingling of offshore marine and terrestrial surface source waters and therefore are naturally complex and variable. Our long term goal is to establish observational and modeling approaches to predict sources and scales of variability in the source waters, particularly those related to land use activities in upstream...
The `Equatorial Box' Project utilizes the mooring observations along the 125 and 140 TAO lines to provide carbon component data, including chlorophyll, primary production, POC and DOC. These parameters together with other oceanographic properties can be used to validate ocean circulation-ecosystem models. In turn, a validated model can offer consid...
The Gulf of Maine Ocean Observing System (GoMOOS) was established in the summer of 2001 as a prototype real-time observing
system that now includes eleven solar-powered buoys with physical and optical sensors, four shore-based long-range HF radar
surface current systems, circulation and wave models, satellite observations, and hourly web delivery o...