Physical Sciences and Mathematics Commons^™

Evaluating Potential For Water Quality Decline In Maine Lakes, Kaci N. Fitzgibbon

Electronic Theses and Dissertations

Understanding lake vulnerability with respect to eutrophication and loss of water quality is important for sustainability of aquatic ecosystems. This project aims at identifying and quantifying the effects of relevant physiochemical, climate, and watershed characteristics on lake vulnerability in order to develop management decision tools for the Maine Department of Environmental Protection (MEDEP). In a changing chemical and physical environment, using independent variables from each of these categories and then relating them to the summer lake epilimnetic phosphorus (P) concentrations allows for development of models to inform stakeholders of lake vulnerability to eutrophication problems.

We studied 24 lakes covering a …

Transformation Of Nonlinear Waves In The Presence Of Wind, Current, And Vegetation, Haifei Chen

Electronic Theses and Dissertations

Accurate prediction of extreme wave events is crucial for the safe maritime activities and offshore operations. Improved knowledge of wave dissipation mechanisms due to breaking and vegetation leads to accurate wave forecast, protecting life and property along the coast. The scope of the thesis is to examine the wave transformations in the presence of wind, current, and vegetation, using a two-phase flow solver based on the open-source platform OpenFOAM. The Reynolds-Averaged Navier-Stokes (RANS) equations are coupled with a Volume of Fluid (VOF) surface capturing scheme and a turbulence closure model. This RANS-VOF model is adapted to develop a numerical wind-wave-current …

Determination Of The Absorption Coefficient Of Chromophoric Dissolved Organic Matter From Underway Spectrophotometry, Giorgio Dall’Olmo, Robert J. W. Brewin, Francesco Nencioli, Emanuele Organelli, Ina Lefering, David Mckee, Rüdiger Röttgers, Catherine Mitchell, Emmanuel Boss, Annick Bricaud, Gavin Tilstone

Marine Sciences Faculty Scholarship

Measurements of the absorption coefficient of chromophoric dissolved organic matter (ay) are needed to validate existing ocean-color algorithms. In the surface open ocean, these measurements are challenging because of low ay values. Yet, existing global datasets demonstrate that ay could contribute between 30% to 50% of the total absorption budget in the 400-450 nm spectral range, thus making accurate measurement of ay essential to constrain these uncertainties. In this study, we present a simple way of determining ay using a commercially-available in-situ spectrophotometer operated in underway mode. The obtained ay values were validated using independent collocated measurements. The method is …

Two Databases Derived From Bgc-Argo Float Measurements For Marine Biogeochemical And Bio-Optical Applications, Emanuele Organelli, Marie Barbieux, Hervé Claustre, Catherine Schmechtig, Antoine Poteau, Annick Bricaud, Emmanuel Boss, Nathan Briggs, Giorgio Dall'olmo, Fabrizio D'Ortenzio, Edouard Leymarie, Antoine Mangin, Grigor Obolensky, Christophe Penkerc'h, Louis Prieur, Collin Roesler, Romain Serra, Julia Uitz, Xiaogang Xing

Marine Sciences Faculty Scholarship

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, downward irradiance at three wavelengths, and photosynthetically available radiation) variables are collected in the upper 1000 m every 1 to 10 days. The database of 9837 vertical profiles collected up to January 2016 is presented and its spatial and temporal coverage is discussed. Each variable is quality controlled with specifically developed procedures and its time series is …

Simplified Model Of Spectral Absorption By Non-Algal Particles And Dissolved Organic Materials In Aquatic Environments, B. B. Cael, Emmanuel Boss

Marine Sciences Faculty Scholarship

© 2017 Optical Society of America. Absorption by non-algal particles (NAP, ad) and colored dissolved organic matter (CDOM, ag) are frequently modeled by exponential functions of wavelength, either separately or as a sum. We present a new representation of NAP-plus-CDOM absorption adg based on the stretched exponential function adg(λ) = Aexp{−[s(λ − λo)]β}, whose parameter β can be considered a measure of optical heterogeneity. A double exponential representation of adg can be fit extremely well by a stretched exponential for all plausible parameter combinations, despite having one fewer free parameter than a double exponential. Fitting two published compilations of in …

Pan-Arctic Optical Characteristics Of Colored Dissolved Organic Matter: Tracing Dissolved Organic Carbon In Changing Arctic Waters Using Satellite Ocean Color Data, Atsushi Matsuoka, Emmanuel Boss, Marcel Babin, Lee Karp-Boss, Mark Hafez, Alex Chekalyuk, Christopher W. Proctor, P. Jeremy Werdell, Annick Bricaud

Marine Sciences Faculty Scholarship

Light absorption of the colored fraction of dissolved organic matter (CDOM) is a dominant optical component of the Arctic Ocean (AO). Here we show Pan-Arctic characteristics of CDOM light absorption for various Arctic regions covering both coastal and oceanic waters during the Tara Oceans Polar Circle expedition. The Siberian (or eastern) side of the AO is characterized by higher CDOM absorption values compared to the North American (or western) side. This is due to the difference in watersheds between the eastern and western sides of the AO and is consistent with an Arctic absorption database recently built by Matsuoka et …

Oyster Aquaculture Site Selection Using Landsat 8-Derived Sea Surface Temperature, Turbidity, And Chlorophyll A., Jordan Snyder

Electronic Theses and Dissertations

Remote sensing data is useful for selection of aquaculture sites because it can provide water-quality products mapped with no cost to users. However, the spatial resolution of most ocean color satellites is too coarse to provide usable data within many estuaries. The more recently launched Landsat 8 satellite has both the spatial resolution and the necessary signal to noise ratio to provide temperature, as well as ocean color derived products along complex coastlines. The state of Maine (USA) has an abundance of estuarine indentations (~3,500 miles of tidal shoreline within 220 miles of coast), and an expanding aquaculture industry, which …

Using Hydroacoustics To Investigate Biological Responses In Fish Abundance To Restoration Efforts In The Penobscot River, Maine, Constantin C. Scherelis

Electronic Theses and Dissertations

Spatiotemporal advantages linked to hydroacoustic sampling techniques have caused a surge in the use of these techniques for fisheries monitoring studies applied over long periods of time in marine systems. Dynamic physical conditions such as tidal height, boat traffic, floating debris, and suspended particle concentrations result in unwanted noise signatures that vary in intensity and location within a hydroacoustic beam over time and can be mixed with the acoustic returns from intended targets (e.g., fish). Typical processing filters applied over long term datasets to minimize noise and maximize signals do not address spatiotemporal fluctuations of noise in dynamic systems. We …

Notes On Contributors

The Catch

No abstract provided.

The Mackerel Fishermen, Avery B. Stone

The Catch

No abstract provided.

Cormorant, Judy Kaber

The Catch

No abstract provided.

Awakening, Angela M. Waldron

The Catch

No abstract provided.

Editor's Note, Leonore Hildebrandt

The Catch

No abstract provided.

Full Issue Volume V

The Catch

No abstract provided.

Recommendations For Obtaining Unbiased Chlorophyll Estimates From In Situ Chlorophyll Fluorometers: A Global Analysis Of Wet Labs Eco Sensors, Collin Roesler, Julia Uitz, Hervé Claustre, Emmanuel Boss, Xiaogang Xing, Emanuele Organelli, Nathan Briggs, Annick Bricaud, Catherine Schmechtig, Antoine Poteau, Fabrizio D'Ortenzio, Josephine Ras, Susan Drapeau, Nils Haëntjens, Marie Barbieux

Marine Sciences Faculty Scholarship

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 relationship between in situ fluorescence and extracted Chl a concentration. Despite this large natural variability, we present here a global validation data set for the WET Labs Environmental Characterization Optics (ECO) series chlorophyll fluorometers that suggests a factor of 2 overestimation in the factory calibrated Chl a estimates for …

Revisiting Ocean Color Algorithms For Chlorophyll A And Particulate Organic Carbon In The Southern Ocean Using Biogeochemical Floats, Nils Haëntjens

Electronic Theses and Dissertations

The Southern Ocean (SO, oceans south of 30 ^oS) ecosystem plays a key role in global carbon cycles by sinking a major part (43 %) of the anthropogenic CO₂, and being an important source of nutrients for primary producers. However, undersampling of SO biogeochemical properties limits our understanding of the mechanisms taking place in this remote area. The Southern Ocean Carbon and Climate Observing and Modeling project (SOCCOM) has been deploying a large number of autonomous biogeochemical floats to study the SO (as of December 2016, 74 floats out of 200 have been deployed). SOCCOM floats measurements …

Analytical Solution Of The Nitracline With The Evolution Of Subsurface Chlorophyll Maximum In Stratified Water Columns, Xiang Gong, Wensheng Jiang, Linhui Wang, Huiwang Gao, Emmanuel Boss, Xiaohong Yao, Shuh Ji Kao, Jie Shi

Marine Sciences Faculty Scholarship

In a stratified water column, the nitracline is a layer where the nitrate concentration increases below the nutrient-depleted upper layer, exhibiting a strong vertical gradient in the euphotic zone. The subsurface chlorophyll maximum layer (SCML) forms near the bottom of the euphotic zone, acting as a trap to diminish the upward nutrient supply. Depth and steepness of the nitracline are important measurable parameters related to the vertical transport of nitrate into the euphotic zone. The correlation between the SCML and the nitracline has been widely reported in the literature, but the analytic solution for the relationship between them is not …

Vector Radiative Transfer Model For Coupled Atmosphere And Ocean Systems Including Inelastic Sources In Ocean Waters, Peng Wang Zhai, Yongxiang Hu, David M. Winker, Bryan A. Franz, Jeremy Werdell, Emmanuel Boss

Marine Sciences Faculty Scholarship

Inelastic scattering plays an important role in ocean optics. The main inelastic scattering mechanisms include Raman scattering, fluorescence by colored dissolved organic matter (FDOM), and fluorescence by chlorophyll. This paper reports an implementation of all three inelastic scattering mechanisms in the exact vector radiative transfer model for coupled atmosphere and ocean Systems (CAOS). Simulation shows that FDOM contributes to the water radiation field in the broad visible spectral region, while chlorophyll fluorescence is limited in a narrow band centered at 685 nm. This is consistent with previous findings in the literature. The fluorescence distribution as a function of depth and …

Bees Of Maine, With A State Species Checklist, Alison C. Dibble, Francis A. Drummond, Constance Stubbs, Michael Veit, John S. Ascher

Biology and Ecology Faculty Scholarship

We present a new county checklist developed from bee research in Maine since the 1800s. The list contains 278 bee species in 37 genera and 6 families, of which all but 8 are native, with ≥50 taxa each in Andrena and Lasioglossum. Data for 16 counties from publications, museum collections, and recent surveys varied in number of species from 8 (Androscoggin) to 197 (Hancock). Research since 1930 on Vaccinium angustifolium (Lowbush Blueberry) led to many records. Twenty-one species are considered unusual, including 3 first recorded in 2016: Epeoloides pilosulus, Melitta melittoides, and Holcopasites calliopsidis. Maine records …