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DOE OSTI2018

Potassic, High-Silica Hadean Crust.

Understanding Hadean(>4 Ga) Earth requires knowledge of its crust. The composition of the crust and volatiles migrating through it directly influence the makeup of the atmosphere, the composition of seawater, and nutrient availability. Despite its importance, there is little known and less agreed upon regarding the nature of the Hadean crust. By analyzing the Sr-87/Sr-86 ratio of apatite inclusions in Archean zircons from Nuvvuagittuq, Canada, we show that its protolith had formed a high (>1) Rb/Sr ratio reservoir by at least 4.2 Ga. This result implies that the early crust had a broad range of igneous rocks, extending from mafic to highly silicic compositions

early Earth↗

DOE OSTI2020

X-ray Scattering Studies of Reverse Osmosis Materials

Scarcity of freshwater is becoming a world crisis. In a recent annual risk report, the World Economic Forum lists it in their greatest global risk category. Currently, about four billion people live under conditions of severe water scarcity for at least one month out of the year [1]. Increasing water use efficiency is thus essential. However, this alone will not be able to provide adequate drinking water to meet the world’s needs. The process of preparing drinking water from seawater and brackish water involves many stages, the final and most expensive of which is typically reverse osmosis (RO). Reverse osmosis processes operate by forcing water across a semi-permeable membrane by applying a pressure greater than the osmotic pressure of the feed solution (seawater, Π ≈ 28 bar = 400 psi), thereby separating the water from any dissolved ions and impurities (rejection > 99%). The flux of water through the membrane is directly proportional to the amount of pressure applied above the osmotic pressure; however, the energy consumption is related to the total pressure. According to the American Membrane Technology Association, the amount of energy required to desalinate seawater with current technologies is 2.5 to 3.5 kWh/m 3 of water. RO materials have been tuned, modified, and optimized extensively since their initial discovery through an Edisonian approach. Despite immense technological progress [2, 3], many basic scientific questions remain on the molecular structure of RO membranes. Overall, in this report, we demonstrate that synchrotron X-ray scattering methods offer the possibility of improving our fundamental understanding of RO materials.

36 MATERIALS SCIENCE↗

DOE OSTI2026

Expedited desalination permitting enables adaptive planning and water system cost reduction

Seawater desalination is a drought-proof water supply for coastal cities, but widespread development of desalination plants in the U.S. has been limited by both cost and the complexity of permitting processes designed to minimize environmental impact . This work estimates the value of accelerating the permitting timeline without changing environmental or social standards. On average, faster permitting reduces the frequency of desalination plant construction and operation, the overall costs of robust water system operation, the environmental impacts of drought-tolerant water supplies due to shorter duration of plant operation. Expedited permitting allows fundamental changes in how water infrastructure is deployed, facilitating a transition from anticipatory construction and continuous operation of seawater desalination capacity as a redundant drought buffer to just-in-time (i.e. adaptive) deployment of seawater desalination capacity when critical drought thresholds are crossed. We demonstrate the value of expedited desalination permitting in enabling adaptive planning and reducing water system costs using a simple case study in Santa Barbara, CA. We discuss additional forms of adaptive water infrastructure planning as enabled by faster permitting and address their challenges and opportunities. Lastly, we identify synergies between innovation in adaptive planning, innovation in expedited permitting practices, and innovation in water technology.

adaptive planning↗

DOE OSTI2024

Underwater unexploded ordnance discrimination based on intrinsic target polarizabilities – A case study

Seabed unexploded ordnance that resulted partly from the high failure rate among munitions from more than 80 years ago and from decades of military training and testing of weapons systems poses an increasing concern all around the world. Although existing magnetic systems can detect clusters of debris, they are not able to tell whether a munition is still intact requiring special removal (e.g. in situ detonation) or is harmless scrap metal. The marine environment poses unique challenges, and transferring knowledge and approaches from land to a marine environment has not been easy and straightforward. On land, the background soil conductivity is much lower than the conductivity of the unexploded ordnance and the electromagnetic response of a target is essentially the same as that in free space. For those frequencies required for target characterization in the marine environment, the seawater response must be accounted for and removed from the measurements. The system developed for this study uses fields from three orthogonal transmitters to illuminate the target and four three-component receivers to measure the signal arranged in a configuration that inherently cancels the system's response due to the enclosing seawater, the sea–bottom interface and the air–sea interface for shallow deployments. The system was tested as a cued system on land and underwater in San Francisco Bay – it was mounted on a simple platform on top of a support structure that extended 1 m below and allowed the diver to place metal objects to a specific location even in low-visibility conditions. The measurements were stable and repeatable. Furthermore, target responses estimated from marine measurements matched those from land acquisition, confirming that the seawater and air–sea interface responses were removed successfully. Thirty-six channels of normalized induction responses were used for the classification, which was done by estimating the target principal dipole polarizabilities. Our results demonstrated that the system can resolve the intrinsic polarizabilities of the target, with clear distinctions between those of symmetric intact unexploded ordnance and irregular scrap metal. The prototype system was able to classify an object based on its size, shape and metal content and correctly estimate its location and orientation.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

DOE OSTI2023

Lower viral evolutionary pressure under stable versus fluctuating conditions in subzero Arctic brines

Climate change threatens Earth’s ice-based ecosystems which currently offer archives and eco-evolutionary experiments in the extreme. Arctic cryopeg brine (marine-derived, within permafrost) and sea ice brine, similar in subzero temperature and high salinity but different in temporal stability, are inhabited by microbes adapted to these extreme conditions. However, little is known about their viruses (community composition, diversity, interaction with hosts, or evolution) or how they might respond to geologically stable cryopeg versus fluctuating sea ice conditions. We used long- and short-read viromics and metatranscriptomics to study viruses in Arctic cryopeg brine, sea ice brine, and underlying seawater, recovering 11,088 vOTUs (~species-level taxonomic unit), a 4.4-fold increase of known viruses in these brines. More specifically, the long-read-powered viromes doubled the number of longer (≥25 kb) vOTUs generated and recovered more hypervariable regions by >5-fold compared to short-read viromes. Distribution assessment, by comparing to known viruses in public databases, supported that cryopeg brine viruses were of marine origin yet distinct from either sea ice brine or seawater viruses, while 94% of sea ice brine viruses were also present in seawater. A virus-encoded, ecologically important exopolysaccharide biosynthesis gene was identified, and many viruses (~half of metatranscriptome-inferred “active” vOTUs) were predicted as actively infecting the dominant microbial genera Marinobacter and Polaribacter in cryopeg and sea ice brines, respectively. Evolutionarily, microdiversity (intra-species genetic variations) analyses suggested that viruses within the stable cryopeg brine were under significantly lower evolutionary pressures than those in the fluctuating sea ice environment, while many sea ice brine virus-tail genes were under positive selection, indicating virus-host co-evolutionary arms races. Our results confirmed the benefits of long-read-powered viromics in understanding the environmental virosphere through significantly improved genomic recovery, expanding viral discovery and the potential for biological inference. Evidence of viruses actively infecting the dominant microbes in subzero brines and modulating host metabolism underscored the potential impact of viruses on these remote and underexplored extreme ecosystems. Microdiversity results shed light on different strategies viruses use to evolve and adapt when extreme conditions are stable versus fluctuating. Together, these findings verify the value of long-read-powered viromics and provide foundational data on viral evolution and virus-microbe interactions in Earth’s destabilized and rapidly disappearing cryosphere.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2024

Greenhouse gas and dissolved oxygen production and consumption rates associated with Regier et al. (2023)

Tidal inundation along the coastal terrestrial-aquatic interface controls soil and sediment biogeochemistry and gas dynamics. Although a rich literature exist on studies of the influence of tidal waters on the biogeochemistry of coastal ecosystem soils, few studies have experimentally addressed the reverse question: How do soils (or sediments) from different coastal ecosystems influence the biogeochemistry of the tidal waters that inundate them? We conducted short-term microcosm laboratory experiments where seawater was amended with sediments and soils collected across regional gradients of inundation exposure (i.e., frequently to rarely inundated) and measured changes in dissolved oxygen and greenhouse gas concentrations to calculate gas consumption or production rates occurring during seawater exposure to terrestrial materials. This data package contains dissolved oxygen and greenhouse gas data collected during incubation of soils and sediments collected at 18 sites, which were used in the publication Regier et al. (2023) entitled “Coastal inundation regime moderates the short-term effects of sediment and soil additions on seawater oxygen and greenhouse gas dynamics: a microcosm experiment” which is published in Frontiers in Marine Science (DOI: https://doi.org/10.3389/fmars.2023.1308590).---Acknowledging EXCHANGE: General Support and Data Product UseWe ask that users of EXCHANGE data add the following acknowledgement when publishing data in scholarly articles and data repositories:"This research is based on work supported by COMPASS-FME, a multi-institutional project supported by the U.S. Department of Energy, Office of Science, Biological and Environmental Research as part of the Environmental System Science Program."

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2026

TEMPEST3 surface runoff water chemistry and organic matter composition

Coastal flooding, driven by storm surges and sea level rise, can mobilize organic matter (OM) via runoff, while introducing compositionally distinct OM (e.g., estuarine OM) into the system. To understand event-scale OM dynamics, we monitored source waters and surface runoff during an ecosystem-scale field manipulation experiment, TEMPEST (Terrestrial Ecosystem Manipulation to Probe the Effects of Storm Treatments), in June 2024. The TEMPEST experiment is part of the COMPASS-FME (Coastal Observations, Mechanisms, and Predictions Across Systems and Scales – Field, Measurements, and Experiments) project and designed to investigate biogeochemical and ecological impacts of freshwater and seawater flooding on coastal terrestrial-aquatic interface ecosystems by simulating freshwater and seawater storm events in two 2000m2 coastal upland forest plots (freshwater and brackish seawater plots). The temporal coverage of this dataset is during the TEMPESTⅢ event (June 11-13, 2024). This dataset contains: - Surface runoff discharge measured by flumes - Sensor data (specific conductivity, salinity, dissolved oxygen, and temperature) - Particle size distribution - Total suspended sediment concentrations (TSS), particulate and dissolved organic carbon (POC, DOC) concentrations, total nitrogen and total dissolved nitrogen (TN, TDN) concentrations - Bulk particulate and dissolved OM compositions (stable C and N isotopes of particulates and optical measurements of chromophoric dissolved OM) - High resolution mass spectrometry analysis data - Water isotope data All data files are plain-text CSV (comma-separated value), and no special software is required to read them.

COMPASS-FME↗

DOE OSTI2017

Cost and Systems Analysis of Innovative Fuel Resources Concepts

Economically recovered uranium from seawater can have a transformative effect on the way policy makers view the long-term viability of uranium based fuel cycles. Seawater uranium, even when estimated to cost more than terrestrially mined uranium, is integral in establishing an economic backstop, thus reducing uncertainty in future nuclear power costs. While a passive recovery scheme relying on a field of polymer adsorbents prepared via radiation induced grafting has long been considered the leading technology for full scale deployment, non-trivial cost and logistical barriers persist. Consequently, university partners of the nation-wide consortium for seawater uranium recovery have developed variants of this technology, each aiming to address a substantial weakness. The focus of this NEUP project is the economic impacts of the proposed variant technologies. The team at University of Alabama has pursued an adsorbent synthesis method that replaces the synthetic fiber backbone with a natural waste product. Chitin fibers suitable for ligand grafting have been prepared from shrimp shell waste. These environmental benefits could be realized at a comparable cost to the reference fiber so long as the uptake can be increased or the chemical consumption cost decreased.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2017

Model-Based Extracted Water Desalination System for Carbon Sequestration

Over the last 1.5 years, GE Global Research and Pennsylvania State University defined a model-based, scalable, and multi-stage extracted water desalination system that yields clean water, concentrated brine, and, optionally, salt. The team explored saline brines that ranged across the expected range for extracted water for carbon sequestration reservoirs (40,000 up to 220,000 ppm total dissolved solids, TDS). In addition, the validated the system performance at pilot scale with field-sourced water using GE’s pre-pilot and lab facilities. This project encompassed four principal tasks, in addition to Project Management and Planning: 1) identify a deep saline formation carbon sequestration site and a partner that are suitable for supplying extracted water; 2) conduct a techno-economic assessment and down-selection of pre-treatment and desalination technologies to identify a cost-effective system for extracted water recovery; 3) validate the downselected processes at the lab/pre-pilot scale; and 4) define the scope of the pilot desalination project. Highlights from each task are described below: Deep saline formation characterization The deep saline formations associated with the five DOE NETL 1260 Phase 1 projects were characterized with respect to their mineralogy and formation water composition. Sources of high TDS feed water other than extracted water were explored for high TDS desalination applications, including unconventional oil and gas and seawater reverse osmosis concentrate. Technoeconomic analysis of desalination technologies Techno-economic evaluations of alternate brine concentration technologies, including humidification-dehumidification (HDH), membrane distillation (MD), forward osmosis (FO), turboexpander-freeze, solvent extraction and high pressure reverse osmosis (HPRO), were conducted. These technologies were evaluated against conventional falling film-mechanical vapor recompression (FF-MVR) as a baseline desalination process. Furthermore, a quality function deployment (QFD) method was used to compare alternate high TDS desalination technologies to FF-MVR. High pressure reverse osmosis was found to a be a promising alternative desalination technology. A deep-dive technoeconomic analysis of HPRO was performed, including Capex and Opex estimates, for seawater RO (SWRO). Additionally, two additional cases were explored: 1) a comparison of a SWRO plus HPRO system to the option of doubling the size of a standard seawater RO system to achieve the same total pure water recovery rate; and 2) a flue gas desulfurization wastewater treatment zero-liquid discharge (ZLD) application, where preconcentration with RO (SWRO or SWRO + HPRO) before evaporation and crystallization was compared to FF-MVR and crystallization technologies without RO preconcentration. Pre-pilot process validation Pre-pilot-scale tests were conducted using field production water to validate key process steps for extracted water pretreatment. Approximately 5,000 gallons of field produced water was processed through, microfiltration, ultrafiltration, and steam regenerable sorbent operations. Smaller quantities were processed through microclarification. In addition, analytical methods (purge-and-trap gas chromatography and Hach TOC analytical methods) were validated. Lab-scale HPRO elements were constructed and tested at high pressures, to identify and mitigate technical risks of the technology. Lastly, improvements in RO membrane materials were identified as the necessary next step to achieve further improvement in element performance at high pressure. Scope of Field Pilot A field pilot for extracted water pretreatment was designed.

20 FOSSIL-FUELED POWER PLANTS↗

DOE OSTI2018

Power Take-off System for Marine Renewable Devices

The Power Take-off (PTO) System for Marine Renewable Devices (Project) envisioned the design, manufacture and testing of a generator that would ultimately be suitable for fully flooded seawater operation. This would require a generator design and bearing system capable of operating in the presence of seawater without corrosion. The original generator concept design focused on a switched reluctance electromagnetic design for the generator with the understanding that the switched reluctance design would be more robust and tolerant of a seawater medium. A trade study was conducted to prove that hypothesis, but the results of the study indicated that there was no benefit to adopting a switched reluctance design over a more conventional synchronous permanent magnet design. In addition, the novelty of the switched reluctance design added more technical risk to the Project than was warranted. ORPC’s cost of energy analyses pointed to reliability as being the most critical factor for achieving Project systems performance advancement (SPA) metrics. Consequently, the choice of a permanent magnet (PM) machine design over a potentially less reliable switched reluctance design was necessary to achieve the Project results. As a result, ORPC determined that a PM design was a more appropriate design to achieve the Project goals and ORPC selected a highly qualified PM generator firm for the design, manufacture and factory testing of the generator. The factory acceptance test (FAT) of the generator took place on March 20-22, 2017 and all tests were successfully passed. Developing a design for a driveline as part of the PTO system required a full understanding of the loads and operating conditions expected. Detailed analyses for developing turbine loads and subsequent definition of bearing specifications were performed using various analytical methods. Two candidate bearing designs were proposed as part of the Project. After initial design work had been completed, ORPC designed a representative full-scale driveline to validate the detailed design of the advanced driveline components. Full-scale components were manufactured, instrumented and tested, simulating actual system parameters. This full-scale bearing test was conducted at the University of Maine Advanced Structures and Composites Laboratory. The purpose of this test was to characterize the frictional losses associated with bearings and test the suitability and functionality of some commercially available shaft couplings and expansion bushings in cross-flow turbine drivelines. In parallel with component testing and dynamometer testing of the PTO system, ORPC performed design work to demonstrate how the advanced PTO system will be integrated with all ORPC turbine generator units (TGUs). The work would focus primarily on the TidGen® TGU and assess how the advanced PTO would be integrated into TidGen® 001 or other units, then field-deployed and tested in an open water environment under actual operational conditions. In addition to the benefits provided to the MHK industry in general, and ORPC in particular, the Project provided benefits to the general public, including the following: • Increased general awareness of the potential for generation of electricity from ocean energy resources • Demonstrated continuing advancements in the commercialization of MHK technologies, making them more likely to contribute to the electricity generation supply in America in the coming years • Continued awareness of the local economic benefits from the MHK industry through job creation and local spending • Confirmation of a path to improvements in availability, power-to-weight ratio (PWR) and reduction in levelized cost of energy (LCOE). All Project tasks were completed, and the Project objectives were accomplished. All project milestones and deliverables were met. The designs, methodologies, practices, testing, data, analysis and lessons learned from the Project are a step forward in the development of the U.S. MHK industry and provide a sound basis for ultimate commercialization of ORPC’s power systems. Based on the what was learned and demonstrated during the Project, ORPC has determined that the ORPC power systems have the potential of accelerating the commercialization of tidal and ocean current MHK power systems.

16 TIDAL AND WAVE POWER↗

DOE OSTI2020

Sequim Campus Master Plan

Based in Richland, Washington, Pacific Northwest National Laboratory (PNNL) is one of ten U.S. Department of Energy (DOE) Office of Science (SC) national laboratories. PNNL is DOE’s premier chemistry, earth sciences, and data analytics laboratory, delivering vital mission impacts in energy resiliency and national security. PNNL has 19 core capabilities, each a powerful combination of world-class staff, state-of-the- art equipment, and mission-ready facilities. These capabilities represent a collective set of skills and a body of world-leading scientific and engineering work that provides exceptional value and mission delivery to DOE, the National Nuclear Security Administration (NNSA), the U.S. Department of Homeland Security (DHS), and other federal agencies and industry through strategic partnership projects on a not-to-interfere basis. Currently operated by Battelle Memorial Institute, PNNL occupies more than 2.3 million gross square feet (GSF) of buildings and employs approximately 4,700 staff members. PNNL has implemented a rolling 10-year campus strategy, initiated in fiscal year 2013, designed to deliver the foundation for the multidisciplinary science and engineering expertise, equipment, instrumentation, facilities, and infrastructure required to continue providing exceptional value and mission delivery. This strategy is incorporated into PNNL’s annual Laboratory Plan, which serves as DOE-SC’s equivalent of the Five- Year Site Plan required by DOE Order 430.1C Chg. 1, Real Property Asset Management. The PNNL Sequim Campus is located in Clallam County, just outside of Sequim, Washington. PNNL Sequim builds upon a rich history of research related to marine and coastal resources, environmental chemistry, water resources modeling, ecotoxicology, biotechnology, and national security. Facilities at the PNNL Sequim Campus were designed to take advantage of two unique locational assets: the pristine coastal ocean water in Sequim Bay and the region’s exceptionally clean air. Research facilities on the waterfront are supplied with up to 200 gallons per minute (gpm) of seawater and/or groundwater that enables research on aquatic systems ranging from fully seawater to fresh water, with an onsite water treatment system that removes all biological and hazardous chemical residues prior to discharge. Multiple large seawater tanks outside the waterfront laboratories, along with a boat ramp, pier, and floating dock, enable lab-to-field research. The uplands facility takes advantage of the amazing air quality and is built and operated to enable ultratrace chemical/radiological analytical chemistry. This combination of capabilities is not available at any other marine laboratory in the nation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Electrochemical Acid Sequestration to Ease Ocean Acidification (EASE-OA) - CRADA 600 (Abstract)

The PNNL team will coordinate logistics involved with setting up the field trial on the PNNL Sequim campus in collaboration with Ebb Carbon. Facilities on the PNNL Sequim campus are capable of pumping raw or filtered seawater from Sequim Bay at a rate ~45,000 L hr -1 , which can accommodate the 4000 L hr -1 requirement of the 200 ton CO2 yr-1 Ebb Carbon marine carbon dioxide removal (mCDR) system. The primary tasks for the PNNL team are 1) laying out appropriate indoor and outdoor spaces for installing the Ebb Carbon’s mCDR system, 2) facilitating Ebb Carbon’s access to the PNNL’s seawater intake on the PNNL Sequim campus, 3) conducting mesocosm experiments within the PNNL Sequim campus laboratories to test how the brine and base discharged from the Ebb Carbon system affect marine life, and 4) facilitating Ebb Carbon access to the PNNL Sequim installation site and aiding in maintenance as needed. In addition to these tasks, the PNNL team will provide surface water quality data (e.g., salinity, temperature, pH, dissolved O2) from a monitoring station located on the pier to contextualize starting conditions of the seawater used in the mCDR process. Finally, the PNNL team will also consult with Ebb Carbon on strategies for improving overall system performance and next steps for further scaling and/or monitoring the effectiveness of the mCDR system.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2023

Post Access Report: Initial testing of wave energy powered UV-C LED anti-biofouling system

In the experiment entitled “Initial Testing of Wave Energy Powered UV-C LED Anti-Biofouling System,” a UV-C LED was used to treat platinum-coated titanium coupons emulating CTD electrode material. An additional control set of coupons were exposed to seawater without the LED treatment. The experimental setup was deployed in seawater tanks at PNNL-Sequim’s Marine and Coastal Research Laboratory (MCRL) for the duration of six months. Tank seawater temperature data were collected for the duration of the experimental campaign. At two-month intervals triplicate sets of coupons were removed from both treatment and control test chambers and weighed to characterize biomass accumulation. After weighing, the coupons were photographed in initial condition, with a stain applied to highlight biofouling growth, and after rinsing off excess stain. These photographs were analyzed using PNNL’s Biofouling Growth Index (BGI) software and with a calculation of percentage dark pixels after conversion to grayscale. Additionally, at the final 6-month datapoint triplicate sets of control and test coupons were sent to PNNL-Richland’s Environmental Molecular Sciences Laboratory (EMSL) for scanning electron microscopy. All data organization and collection methods are described in further detail in the document “TEAMER_3newable_Data_Guide.pdf.” Biomass accumulation increased over time on both sets of coupons, and percent area biofouled demonstrated a similar trend. Analysis of the collected data resulted in the findings that treatment method has an impact on biofouling growth, though to a much less significant extent than time does. Additionally, qualitative findings included the presence of advanced life forms such as worms in the control test chamber, but not in the treated test chamber.

16 TIDAL AND WAVE POWER↗

DOE OSTI2021

Patterns of Element Incorporation in Calcium Carbonate Biominerals Recapitulate Phylogeny for a Diverse Range of Marine Calcifiers

Elemental ratios in biogenic marine calcium carbonates are widely used in geobiology, environmental science, and paleoenvironmental reconstructions. It is generally accepted that the elemental abundance of biogenic marine carbonates reflects a combination of the abundance of that ion in seawater, the physical properties of seawater, the mineralogy of the biomineral, and the pathways and mechanisms of biomineralization. Here we report measurements of a suite of nine elemental ratios (Li/Ca, B/Ca, Na/Ca, Mg/Ca, Zn/Ca, Sr/Ca, Cd/Ca, Ba/Ca, and U/Ca) in 18 species of benthic marine invertebrates spanning a range of biogenic carbonate polymorph mineralogies (low-Mg calcite, high-Mg calcite, aragonite, mixed mineralogy) and of phyla (including Mollusca, Echinodermata, Arthropoda, Annelida, Cnidaria, Chlorophyta, and Rhodophyta) cultured at a single temperature (25°C) and a range of p CO 2 treatments (ca. 409, 606, 903, and 2856 ppm). This dataset was used to explore various controls over elemental partitioning in biogenic marine carbonates, including species-level and biomineralization-pathway-level controls, the influence of internal pH regulation compared to external pH changes, and biocalcification responses to changes in seawater carbonate chemistry. The dataset also enables exploration of broad scale phylogenetic patterns of elemental partitioning across calcifying species, exhibiting high phylogenetic signals estimated from both uni- and multivariate analyses of the elemental ratio data (univariate: λ = 0–0.889; multivariate: λ = 0.895–0.99). Comparing partial R 2 values returned from non-phylogenetic and phylogenetic regression analyses echo the importance of and show that phylogeny explains the elemental ratio data 1.4–59 times better than mineralogy in five out of nine of the elements analyzed. Therefore, the strong associations between biomineral elemental chemistry and species relatedness suggests mechanistic controls over element incorporation rooted in the evolution of biomineralization mechanisms.

58 GEOSCIENCES↗

DOE OSTI2023

Tropical Red Macroalgae Cultivation with a Focus on Compositional Analysis

To create carbon efficient sources of bioenergy feedstocks and feedstuff for aquaculture and terrestrial livestock, it is critical to develop and commercialize the most efficient seaweed cultivation approach with a sustainable nutrient input supply. Here, we present data for a novel, onshore tropical macroalgae cultivation system, based on influent deep seawater as the nutrient and carbon sources. Two red algal species were selected, Agardhiella subulata and Halymenia hawaiiana, as the basis for growth optimization. Highest productivity in small-scale cultivation was demonstrated with A. subulata in the 10% deep seawater (64.7 µg N L−1) treatment, growing at up to 26% specific growth rate day−1 with highest yields observed at 247.5 g m−2 day−1 fresh weight. The highest yields for H. hawaiiana were measured with the addition of 10% deep seawater up to 8.8% specific growth rate day−1 and yields at 63.3 g fresh weight m−2 day−1 equivalent. Biomass should be culled weekly or biweekly to avoid density limitations, which likely contributed to a decrease in SGR over time. With a measured 30–40% carbon content of the ash-free dry weight (20–30% of the dry weight) biomass, this translates to an almost 1:1 CO2 capture to biomass ratio. The compositional fingerprint of the high carbohydrate content of both Agardhiella and Halymenia makes for an attractive feedstock for downstream biorefinery applications. By focusing on scaling and optimizing seaweed farming technologies for large-scale onshore farms, the opportunities for yield potential, adaptability to cultivation conditions, and meeting global sustainability goals through novel, carbon-negative biomass sources such as seaweed can be realized.

09 BIOMASS FUELS↗

NASA NTRS1984

Salts in the dry valleys of Antartica

The Dry Valleys of Antarctica are examples of polar deserts which are rare geological features on the Earth. Such deserts typically have high salinities associated with their closed-basin waters and on many surficial materials throughout them. In order to examine the possible sources for the salts observed in association with the soils in the Dry Valleys. The chloride and bromide concentrations of the water leachates from 58 soils and core samples were measured. The Cl/Br ratio for seawater is 289 and ratios measured for most of the 58 soils studied (greater than 85% of the soils studied) was larger than the seawater ratio (ratios typically were greater than 1000 and ranged up to 50,000). The enrichment in Cl relative to Br is strong evidence that the alts present within the soils were derived from seawater during ordinary evaporation processes, and not from the deposition of Cl and Br from aerosols or from rock weathering as has often been suggested.

Gibson, E. K., Jr.↗

NASA NTRS1986

Effects of external environments on the short beam shear strength of filament wound graphite/epoxy

Filament wound graphite/epoxy samples were immersed in seawater, deionized water, and toluene at room temperature and 80 deg C for 5, 15, and 43 days, and in methanol at room temperature for 15 and 43 days. The percent weight gains and short beam shear strengths were determined after environmental exposure. Samples immersed in deionized water and seawater had higher percent weight gains than those immersed in toluene at room temperature and 80 deg C. The percent weight gains for samples immersed in methanol at room temperature were comparable to those of deionized water and seawater immersed samples. A comparison of percent decreases in short beam shear strengths could not be made due to a large scatter in data. This may indicate defects in samples due to machining or variations in material properties due to processing.

Penn, B. G.↗

NASA NTRS1987

Hydroxide decomposition of dimethylsulfoniopropionate to form dimethylsulfide

The kinetics of DMS production resulting from reaction of OH(-) with DMSP were investigated as a function of hydroxide concentration and temperature. The reaction was first-order with respect to DMSP and OH(-). The second order rate constant at 20+/-1 C is 0.0044/M/sec. The activation energy for this reaction is 14.4 kcal/mode. The investigation indicates that the rate of reaction of DMSP with OH(-) is very slow at the pH of seawater, suggesting that DMSP, which may be a major precursor of DMS in seawater, decomposes in the ocean by other mechanisms. A bacterium which produces DMS from DMSP quantitatively at rates many orders of magnitude higher than indicated by OH(-1) decomposition has been cultured, suggesting that enzymatic processes accelerate the production of DMS from DMSP in seawater.

Dacey, John W. H.↗