SENSORS: Collaborative Research: ALOHA Mooring Sensor Network and Adaptive Sampling

The PIs propose to develop a moored deep-ocean sensor network that will first be installed at the Hawaii Ocean Time-series (HOT)/ALOHA Observatory (AO) and then at other cabled observatory sites as they are implemented. This moored sensor network is based on a profiler that will move between near-surface and fixed abyssal sensors under program control. The PIs feel that this project will demonstrate the scientific potential of combining adaptive sampling methods with a moored series of profiling sensors. The PIs will also develop optimization software tools to maximize overall information return given the constraints of competing scientific objectives, the continually changing environment that will be observed, and the physical limitations of the observing sensors and network. The power and two-way real time communications capability provided by the recently funded cabled ALOHA Observatory is essential to the sampling improvements and sensor network proposed here

COLLABORATIVE RESEARCH: Centers for Ocean Science Education Excellence- Ocean in the Earth-Sun System

This award establishes a new Center for Ocean Science Education Excellence (COSEE) via awards to the Bigelow Laboratory for Ocean Sciences (0528706), the University of Maine (0528702), and the University of New Hampshire (0528686). The main goals of this thematic Center are to broaden understanding of the oceans in the context of the earth and solar systems and to help the COSEE network reach rural and inland audiences. The PIs will pioneer a system of interfaces, tools, and resources to reach underserved and underrepresented groups, and to bring ocean sciences to inland audiences by presenting it in the context of more familiar components of the earth system, including environmental and space sciences. One goal is to explore the effectiveness of expanding knowledge of the ocean\u27s role beyond being a driver of earth\u27s climate to placing the earth in the context of its unique place in the solar system. Activities include building and training educator-scientist teams to work towards specific goals, e.g., testing strategies for effective use of ocean data, training in the use of concept mapping, and the identification and evaluation of high-quality resources. Evaluation of products, models and information is integrated throughout, with continuous self-assessment. Formal education partners at the University of Maine and University of New Hampshire will test the efficacy of materials with educators whose knowledge of ocean-related content ranges from novice to expert. Maine will be a test bed for the COSEE network to start reaching inland rural populations. The team includes scientists and educators with expertise in the hydrosphere, biosphere, cryosphere, geosphere, and atmosphere. The team will develop concept maps and case studies that show application of ocean topics to the National Science Education Standards. The Center will develop a formal mechanism for scientific review of materials to ensure the products they recommend are of the highest quality and meet rigorous standards, as well as to provide feedback from educators and scientists to product developers. They will select resources from DLESE, the BRIDGE, NOAA and others and evaluate these for classroom readiness and scientific accuracy using their team of well-trained resource evaluators with first-hand knowledge of earth systems science. They also will do a gap analysis of missing resources. The Gap Analysis will also inform the science community about avoiding developing materials for well-covered topics. The review process developed by COSEE-OESS, from initial use of NASA\u27s education product review, will be disseminated nationally as a model for evaluating best practices and assessment and evaluation guidelines for education materials.In-service teacher programs will focus on expansion of University of New Hampshire\u27s Coastal Observing Center summer in-service teacher workshops to incorporate OESS content and evaluation of activities ( test bed for novel materials and activities). These workshops have annual themes focusing on ocean observing systems and the integration of buoy, shipboard, and satellite data (GoMOOS). Pre-service teachers and general science students at the University of Maine will take a new course created by OESS to learn ocean research methods by focusing on using physical principles, concepts and approaches to explain phenomena in aquatic sciences that are aligned to the NSES. The course will be developed for distribution to teachers after rigorous evaluation.Intellectual Merit of the Center: This thematic center focuses on creating and evaluating a series of interconnected tools and techniques designed to broaden understanding of the ocean in the context of the earth and solar systems. Results will be translated into innovative multimedia products that showcase the ocean in the earth-sun system. Educational resources will be evaluated for science and education impact, and gaps in these resources will be identified and filled. A new undergraduate course to teach about ocean phenomena will be developed, tested, and disseminated nationally. The proposed Center will help COSEE reach inland and rural audiences. Broader impact: This Center will serve as a learning organization to deliver excellent products, models, and information that can be applied virtually anywhere. The final products, publication of Best Practices (a document that describes the value of system context in terms of learning) and Strategies to reach inland audiences will be disseminated throughout and beyond the COSEE network

The HydroColor app: Above water measurements of remote sensing reflectance and turbidity using a smartphone camera

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. HydroColor is a mobile application that utilizes a smartphone’s camera and auxiliary sensors to measure the remote sensing reflectance of natural water bodies. HydroColor uses the smartphone’s digital camera as a three-band radiometer. Users are directed by the application to collect a series of three images. These images are used to calculate the remote sensing reflectance in the red, green, and blue broad wavelength bands. As with satellite measurements, the reflectance can be inverted to estimate the concentration of absorbing and scattering substances in the water, which are predominately composed of suspended sediment, chlorophyll, and dissolved organic matter. This publication describes the measurement method and investigates the precision of HydroColor’s reflectance and turbidity estimates compared to commercial instruments. It is shown that HydroColor can measure the remote sensing reflectance to within 26% of a precision radiometer and turbidity within 24% of a portable turbidimeter. HydroColor distinguishes itself from other water quality camera methods in that its operation is based on radiometric measurements instead of image color. HydroColor is one of the few mobile applications to use a smartphone as a completely objective sensor, as opposed to subjective user observations or color matching using the human eye. This makes HydroColor a powerful tool for crowdsourcing of aquatic optical data

Improved irradiances for use in ocean heating, primary production, and photo-oxidation calculations

Accurate calculation of underwater light is fundamental to predictions of upper-ocean heating, primary production, and photo-oxidation. However, most ocean models simulating these processes do not yet incorporate radiative transfer modules for their light calculations. Such models are often driven by abovesurface, broadband, daily averaged irradiance or photosynthetically available radiation (PAR) values obtained from climatology or satellite observations, sometimes without correction for sea-surface reflectance, even though surface reflectance can reduce in-water values by more than 20%. We present factors computed by a radiative transfer code that can be used to convert above-surface values in either energy or quantum units to in-water net irradiance, as needed for calculations of water heating, and to inwater PAR, as needed for calculations of photosynthesis and photo-oxidation

Evaluation of a compact sensor for backscattering and absorption

Seawater inherent optical properties (IOPs) are key parameters in a wide range of applications in environmental studies and oceanographic research. In particular, the absorption coefficient (a) is the typical IOP used to obtain the concentration of chlorophyll-a in the water-a critical parameter in biological oceanography studies and the backscattering coefficient (bb) is used as a measure of turbidity. In this study, we test a novel instrument concept designed to obtain both the absorption and backscattering coefficients. The instrument would emit a collimated monochromatic light beam into the water retrieving the backscattered light intensity as a function of distance from the center of illumination. We use Monte Carlo modeling of light propagation to create an inversion algorithm that translates the signal from such an instrument into values of a and bb. Our results, based on simulations spanning the bulk of natural values of seawater IOP combinations, indicate that a 6:2cm diameter instrument with a radial resolution of 1cm would be capable of predicting bb within less than 13.4% relative difference and a within less than 57% relative difference (for 90% of the inverted a values, the relative errors fall below 29.7%). Additionally, these errors could be further reduced by constraining the inversion algorithm with information from concurrent measurements of other IOPs. Such a compact and relatively simple device could have multiple applications for in situ optical measurements, including a and bb retrievals from instrumentation mounted on autonomous underwater vehicles. Furthermore, the same methodology could possibly be used for an out-of-water sensor

Turbulence-plankton interactions : a new cartoon

Author Posting. © John Wiley & Sons, 2009. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Marine Ecology 30 (2009): 133-150, doi:10.1111/j.1439-0485.2009.00288.x.Climate change will alter turbulence intensity, motivating greater attention to mechanisms of turbulence effects on organisms. Many analytic and analog models used to simulate and assess effects of turbulence on plankton rely on a one-dimensional simplification of the dissipative scales of turbulence, i.e., simple, steady, uniaxial shears, as produced in Couette vessels. There shear rates are constant and spatially uniform, and hence so is vorticity. Studies in such Couette flows have greatly informed, spotlighting stable orientations of nonspherical particles and predictable, periodic, rotational motions of steadily sheared particles in Jeffery orbits that steepen concentration gradients around nutrient-absorbing phytoplankton and other chemically (re)active particles. Over the last decade, however, turbulence research within fluid dynamics has focused on the structure of dissipative vortices in space and time and on spatially and temporally varying 2 vorticity fields in particular. Because steadily and spatially uniformly sheared flows are exceptional, so therefore are stable orientations for particles in turbulent flows. Vorticity gradients, finite net diffusion of vorticity and small radii of curvature of streamlines are ubiquitous features of turbulent vortices at dissipation scales that are explicitly excluded from simple, steady Couette flows. All of these flow components contribute instabilities that cause rotational motions of particles and so are important to simulate in future laboratory devices designed to assess effects of turbulence on nutrient uptake, particle coagulation and predatorprey encounter in the plankton. The Burgers vortex retains these signature features of turbulence and provides a simplified “cartoon” of vortex structure and dynamics that nevertheless obeys the Navier-Stokes equations. Moreover, this idealization closely resembles many dissipative vortices observed in both the laboratory and the field as well as in direct numerical simulations of turbulence. It is simple enough to allow both simulation in numerical models and fabrication of analog devices that selectively reproduce its features. Exercise of such numerical and analog models promises additional insights into mechanisms of turbulence effects on passive trajectories and local accumulations of both living and nonliving particles, into solute exchange with living and nonliving particles and into more subtle influences on sensory processes and swimming trajectories of plankton, including demersal organisms and settling larvae in turbulent bottom boundary layers. The literature on biological consequences of vortical turbulence has focused primarily on the smallest, Kolmogorov-scale vortices of length scale η. Theoretical dissipation spectra and direct numerical simulation, however, indicate that typical dissipative vortices with radii of 7η to 8η, peak azimuthal speeds of order 1 cm s-1 and lifetimes of order 10 s as a minimum (and much longer for moderate pelagic turbulence intensities) deserve new attention in studies of biological effects of turbulence.This research was supported by collaborative U.S. National Science Foundation grant (OCE- 0724744) to Jumars and Karp-Boss

Uncertainties of inherent optical properties obtained from semianalytical inversions of ocean color

We present a method to quantify the uncertainties in the in-water constituent absorption and backscattering coefficients obtained from an inversion of remotely sensed reflectance (rrs). We first find a set of positive inversion solutions within a given uncertainty range around the values of the inverted rrs. The uncertainties of the solutions are then computed based on the statistics of these solutions. We demonstrate the uncertainty calculation algorithm using a specific semianalytic inversion model applied to both a field and a simulated data set. When the associated uncertainties are taken into account, the inverted parameters are generally within the uncertainties of the measured (or simulated) parameters, highlighting the success of the inversion and the method to obtain uncertainties. The specific inversion we use, however, fails to retrieve two spectral parameters within a usable range. The method presented is general and can be applied to all existing semianalytical inversion algorithms

Rate and apparent quantum yield of photodissolution of sedimentary organic matter

Author Posting. © Association for the Sciences of Limnology and Oceanography, 2012. This article is posted here by permission of Association for the Sciences of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 57 (2012): 1743-1756, doi:10.4319/lo.2012.57.6.1743.We quantified rates of photochemical dissolution (photodissolution) of organic carbon in coastal Louisiana suspended sediments, conducting experiments under well-defined conditions of irradiance and temperature. Optical properties of the suspended sediments were characterized and used in a radiative transfer model to compute irradiances within turbid suspensions. Photodissolution rate increased with temperature (T), with activation energy of 32 ± 7 kJ mol−1, which implicates indirect (non-photochemical) steps in the net reaction. In most samples, dissolved organic carbon (DOC) concentration increased approximately linearly with time over the first 4 h of irradiation under broadband simulated sunlight, after higher rates in the initial hour of irradiation. Four-hour rates ranged from 2.3 µmol DOC m−3 s−1 to 3.2 µmol DOC m−3 s−1, but showed no relation to sample origin within the study area, organic carbon or reducible iron content, or mass-specific absorption coefficient. First-hour rates were higher—from 3.5 µmol DOC m−3 s−1 to 7.8 µmol DOC m−3 s−1—and correlated well with sediment reducible iron (itself often associated with organic matter). The spectral apparent quantum yield (AQY) for photodissolution was computed by fitting DOC photoproduction rates under different spectral irradiance distributions to corresponding rates of light absorption by particles. The photodissolution AQY magnitude is similar to most published dissolved-phase AQY spectra for dissolved inorganic carbon photoproduction, which suggests that in turbid coastal waters where particles dominate light absorption, DOC photoproduction from particles exceeds photooxidation of DOC.We would like to acknowledge funding support from the National Science Foundation Chemical Oceanography program (L.M. and M.L.E.), a National Aeronautics and Space Administration Earth Systems Science Graduate Fellowship (M.L.E.), and the Office of Naval Research Environmental Optics program (E.B.)

Plankton imagery data inform satellite-based estimates of diatom carbon

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chase, A. P., Boss, E. S., Haentjens, N., Culhane, E., Roesler, C., & Karp-Boss, L. Plankton imagery data inform satellite-based estimates of diatom carbon. Geophysical Research Letters, 49(13), (2022): e2022GL098076, https://doi.org/10.1029/2022GL098076.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, despite a lack of validation against independent diatom biomass measurements. We used imaging-in-flow cytometry to quantify diatom carbon in the western North Atlantic, and compared results to those obtained from accessory pigment-based approximations. Based on this analysis, we offer a new empirical formula to estimate diatom carbon concentrations from chlorophyll a. Additionally, we developed a neural network model in which we integrated chlorophyll a and environmental information to estimate diatom carbon distributions in the western North Atlantic. The potential for improving satellite-based diatom carbon estimates by integrating environmental information into a model, compared to models that are based solely on chlorophyll a, is discussed.Funding for this work was provided by NASA grants #NNX15AE67G and #80NSSC20M0202. A. Chase is supported by a Washington Research Foundation Postdoctoral Fellowship

Evaluation of ocean color remote sensing algorithms for diffuse attenuation coefficients and optical depths with data collected on BGC-Argo floats

The vertical distribution of irradiance in the ocean is a key input to quantify processes spanning from radiative warming, photosynthesis to photo-oxidation. Here we use a novel dataset of thousands local-noon downwelling irradiance at 490 nm (Ed(490) and photosynthetically available radiation (PAR) profiles captured by 103 BGC-Argo floats spanning three years (from October 2012 to January 2016) in the world\u27s ocean, to evaluate several published algorithms and satellite products related to diffuse attenuation coefficient (Kd). Our results show: (1) MODIS-Aqua Kd(490) products derived from a blue-to-green algorithm and two semi-analytical algorithms show good consistency with the float-observed values, but the Chla-based one has overestimation in oligotrophic waters; (2) The Kd(PAR) model based on the Inherent Optical Properties (IOPs) performs well not only at sea-surface but also at depth, except for the oligotrophic waters where Kd(PAR) is underestimated below two penetration depth (2zpd), due to the model\u27s assumption of a homogeneous distribution of IOPs in the water column which is not true in most oligotrophic waters with deep chlorophyll-a maxima; (3) In addition, published algorithms for the 1% euphotic-layer depth and the depth of 0.415 mol photons m-2 d-1 isolume are evaluated. Algorithms based on Chla generally work well while IOPs-based ones exhibit an overestimation issue in stratified and oligotrophic waters, due to the underestimation of Kd(PAR) at depth