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All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Raw liquid waste treatment process

A raw sewage treatment process is disclosed in which substantially all the non-dissolved matter, which is suspended in the sewage water is first separated from the water, in which at least organic matter is dissolved. The non-dissolved material is pyrolyzed to form an activated carbon and ash material without the addition of any conditioning agents. The activated carbon and ash material is added to the water from which the non-dissolved matter was removed. The activated carbon and ash material absorbs organic matter and heavy metal ions, it is believed, are dissolved in the water and is thereafter supplied in a counter current flow direction and combined with the incoming raw sewage to facilitate the separation of the non-dissolved settleable materials from the sewage water. The used carbon and ash material together with the non-dissolved matter which was separated from the sewage water are pyrolyzed to form the activated carbon and ash material.

Humphrey, Marshall F.↗
NASA NTRS2023

Remote Sensing of Dissolved Organic Carbon (DOC) Stocks, Fluxes and Transformations Along the Land-Ocean Aquatic Continuum: Advances, Challenges, and Opportunities

From stream headwaters to the deep ocean, dissolved organic carbon (DOC) is ubiquitous across the world’s aquatic systems, where it fulfills important biogeochemical and ecological functions. Importantly, DOC is a dynamic component of the carbon cycle and represents a global reservoir (mass of carbon) equivalent in size to the atmospheric CO 2 pool. The mobilization, transport, and transformations of DOC along the land-ocean aquatic continuum biogeochemically connect terrestrial landscapes, freshwater and marine ecosystems, and the atmosphere. As a result, DOC budgets are vulnerable to climate- and human-driven changes. Having the ability to quantify DOC stocks, fluxes, and transformations consistently and accurately in aquatic systems is therefore critical to our understanding of DOC’s functions in the environment and of their susceptibility to change. In recent years, optical techniques and synoptic earth observations have opened new doors to achieve this objective on a global scale. In this review, we explore how in situ measurements, earth observations, and the models they inform have facilitated the large-scale quantification of DOC stocks, fluxes, and transformations along the land-ocean aquatic continuum and how they have helped shape our current understanding of the global DOC cycle. The review also explores the limitations and challenges we still face today, and discusses how upcoming and future sensors are expected to provide new insights into our understanding of the global DOC cycle.

Dissolved organic carbon↗
NASA NTRS1992

The role of certain infauna and vascular plants in the mediation of redox reactions in marine sediments

The mechanisms by which certain animals and plants affect redox processes in sediments was examined by studying three environments: (1) subtidal sediments dominated by the deposit-feeding polychaete Heteromastus filiformis; (2) a saltmarsh inhabited by the tall form of Spartina alterniflora; and (3) tropical carbonate sediments inhabited by three species of seagrasses. S-35-sulfide production rates were compared to pool sizes of dissolved sulfide and dissolved iron. In all of the sediments studied, rates of sulfide reduction were enhanced by macroorganisms while the rate of turnover of dissolved sulfide increased. The polychaete enhanced microbial activity and redox cycling primarily by subducting particles of organic matter and oxidized iron during sediment reworking. The Spartina species enhanced anaerobic activity by transporting primarily dissolved organic matter and oxidants. Although the final result of both animal and plant activities was the enhancement of sub-surface cycling of sulfur and iron, decreased dissolved sulfide and increased dissolved iron concentrations, the mechanisms which produced these results differed dramatically.

Hines, Mark E.↗
NASA NTRS1985

Cyanobacterial mats: Microanalysis of community metabolism

The microbial communities in two sites were studied using several approaches: (1) light microscopy; (2) the measurement of microprofiles of oxygen and sulfide at the surface of the microbial mat; (3) the study of diurnal variation of oxygen and sulfides; (4) in situ measurement of photosynthesis and sulfate reduction and study of the coupling of these two processes; (5) measurement of glutathione in the upper layers of the microbial mat as a possible oxygen quencher; (6) measurement of reduced iron as a possible intermediate electron donor along the established redoxcline in the mats; (7) measurement of dissolved phosphate as an indicator of processes of break down of organic matter in these systems; and (8) measurement of carbon dioxide in the interstitial water and its delta C-13 in an attempt to understand the flow of CO2 through the systems. Microbial processes of primary production and initial degradation at the most active zone of the microbial mat were analyzed.

Cohen, Y.↗
NASA NTRS1993

Stable isotopic biogeochemistry of carbon and nitrogen in a perennially ice-covered Antarctic lake

Lake Hoare (77 degrees 38' S, 162 degrees 53' E) is an amictic, oligotrophic, 34-m-deep, closed-basin lake in Taylor Valley, Antarctica. Its perennial ice cover minimizes wind-generated currents and reduces light penetration, as well as restricts sediment deposition into the lake and the exchange of atmospheric gases between the water column and the atmosphere. The biological community of Lake Hoare consists solely of microorganisms -- both planktonic populations and benthic microbial mats. Lake Hoare is one of several perennially ice-covered lakes in the McMurdo Dry Valleys that represent the end-member conditions of cold desert and saline lakes. The dry valley lakes provide a unique opportunity to examine lacustrine processes that operate at all latitudes, but under an extreme set of environmental conditions. The dry valley lakes may also offer a valuable record of catchment and global changes in the past and present. Furthermore, these lakes are modern-day equivalents of periglacial lakes that are likely to have been common during periods of glacial maxima at temperate latitudes. We have analyzed the dissolved inorganic carbon (DIC) of Lake Hoare for delta 13C and the organic matter of the sediments and sediment-trap material for delta 13C and delta 15N. The delta 13C of the DIC indicates that 12C is differentially removed in the shallow, oxic portions of the lake via photosynthesis. In the anoxic portions of the lake (27-34 m) a net addition of 12C to the DIC pool occurs via organic matter decomposition. The dissolution of CaCO3 at depth also contributes to the DIC pool. Except near the Canada Glacier where a substantial amount of allochthonous organic matter enters the lake, the organic carbon being deposited on the lake bottom at different sites is isotopically similar, suggesting an autochthonous source for the organic carbon. Preliminary inorganic carbon flux calculations suggest that a high percentage of the organic carbon fixed in the water column is remineralized as it falls through the water column. At nearby Lake Fryxell, the substantial (relative to Lake Hoare) glacial meltstream input overprints Fryxell's shallow-water biological delta 13C signal with delta 13C-depleted DIC. In contrast, Lake Hoare is not significantly affected by surface-water input and mixing, and therefore the delta 13C patterns observed arise primarily from biological dynamics within the lake. Organic matter in Lake Hoare is depleted in 15N, which we suggest is partially the result of the addition of relatively light inorganic nitrogen into the lake system from terrestrial sources.

NASA Program Exobiology↗
NASA NTRS1978

Aerial photographic water color variations from pollution in the James River

A photographic flight was made over the James River on May 17, 1977. The data show that, in general, James River water has very high sunlight reflectance. In the Bailey Bay area this reflectance is drastically reduced. Also shown is a technique for normalizing off-axis variations in radiance film exposure from camera falloff and uneven sunlight conditions to the nadir value. After data normalization, a spectral analysis is performed that identifies Bailey Creek water in James River water. The spectral results when compared with laboratory spectrometer data indicate that reflectance from James River water is dominated by suspended matter, while the substance most likely responsible for reduced reflectance in Bailey Creek water is dissolved organic carbon.

Bressette, W. E.↗
NASA NTRS2023

The Sensitivity of the Equatorial Pacific ODZ to Particulate Organic Matter Remineralization in A Climate Model Under Pre-Industrial Conditions

Marine oxygen plays a fundamental role in regulating the transfer of organic carbon and nutrients to their dissolved inorganic forms, serving as the terminal electron acceptor for heterotrophic respiration. Oxygen can become limiting to these processes in coastal and open-ocean oxygen deficient zones (ODZs). The maintenance of ODZs depends on the balance between physical processes such as ventilation and biogeochemical processes such as remineralization. These two processes act in opposing directions on ODZs, with ventilation responsible for transporting oxygen from the surface, where it is near saturation with the partial pressure of O2 in the atmosphere, to deeper oxygen-depleted layers, and remineralization acting to consume oxygen through biogeochemical processes such as microbial degradation throughout the water column. Remineralization is represented in all CMIP6 models, but the actual parameterizations, as well as their magnitude, are widely varying. In this study, we examine the sensitivity to remineralization of the equatorial Pacific ODZ O2 ol/kg) in a model; the NASA GISS Ocean Biogeochemical Model (NOBM-G) embedded in the NASA-GISS coupled atmosphere-ocean model. We find that increasing the remineralization rate shoals the ODZ onset depth (i.e. the regionally averaged upper bound of the ODZ), and decreases ODZ volume and regional-averaged thickness. Changes in biological consumption and vertical convergence of oxygen are identified as the primary contributors to changes in ODZ onset depth. ODZ thickness is mainly influenced by the shoaling of the bottom boundary of the ODZ, which decreases with maximum remineralization rate due to decreasing oxygen consumption and increasing horizontal oxygen convergence in deep waters. On the other hand, vertically-averaged ODZ area has a more complex, non-monotonic relationship with maximum remineralization rate. While these findings suggest an important role for remineralization in determining the shape of the ODZ in our model, the relative importance of remineralization vs. other physical parameterizations remains to be established. While our results reflect the structure of our ocean biogeochemical model, the relationship of remineralization to ODZ characteristics in other models should be examined to better inform model inter-comparisons.

Oxygen-deficient zone↗
NASA NTRS1990

Carbonate petrography, kerogen distribution, and carbon and oxygen isotope variations in an early Proterozoic transition from limestone to iron-formation deposition, Transvaal Supergroup, South Africa

The transition zone comprises Campbellrand microbialaminated (replacing "cryptalgalaminate") limestone and shale, with minor dolomite, conformably overlain by the Kuruman Iron Formation of which the basal part is characterized by siderite-rich microbanded iron-formation with minor magnetite and some hematite-containing units. The iron-formation contains subordinate intraclastic and microbialaminated siderite mesobands and was deposited in deeper water than the limestones. The sequence is virtually unaltered with diagenetic mineral assemblages reflecting a temperature interval of about 110 degrees to 170 degrees C and pressures of 2 kbars. Carbonate minerals in the different rock types are represented by primary micritic precipitates (now recrystallized to microsparite), early precompactional sparry cements and concretions, deep burial limpid euhedral sparites, and spar cements precipitated from metamorphic fluids in close contact with diabase sills. Paragenetic pathways of the carbonate minerals are broadly similar in all lithofacies with kerogen intimately associated with them. Kerogen occurs as pigmentation in carbonate crystals, as reworked organic detritus in clastic-textured carbonate units, and as segregations of kerogen pigment around late diagenetic carbonate crystals. Locally kerogen may also be replaced by carbonate spar. Carbon isotope compositions of the carbonate minerals and kerogen are dependent on their mode of occurrence and on the composition of the dominant carbonate species in a specific lithofacies. Integration of sedimentary, petrographic, geochemical, and isotopic results makes it possible to distinguish between depositional, early diagenetic, deep burial, and metamorphic effects on the isotopic compositions of the carbonate minerals and the kerogen in the sequence. Major conclusions are that deep burial thermal decarboxylation led to 13C depletion in euhedral ferroan sparites and 13C enrichment in kerogen (organic carbon). Metamorphic sparites are most depleted in 13C. Carbonates in oxide-rich iron-formations are more depleted in 13C than those in siderite-rich iron-formation whereas the kerogens in oxide banded iron-formations (BIF) are more enriched. This implies that the siderite-rich iron-formations were not derived from oxide-rich iron-formation through reduction of ferric iron by organic matter. Organic matter oxidation by ferric iron did, however, decrease the abundance of kerogen in oxide-rich iron-formation and led to the formation of isotopically very light sparry carbonates. Siderite and calcmicrosparite both represent recrystallized primary micritic precipitates but differ in their 13C composition, with the siderites depleted in 13C by 4.6 per mil on average relative to calcmicrosparite. This means that the siderites were precipitated from water with dissolved inorganic carbon depleted in 13C by about 9 per mil relative to that from which the limestones precipitated. This implies an ocean system stratified with regard to total carbonate, with the deeper water, from which siderite-rich iron-formation formed, depleted in 13C. Iron-formations were deposited in areas of very low organic matter supply. Depletion of 13C may, therefore, derive not from degradation of organic matter but from hydrothermal activity, a conclusion which is supported by 18O composition of the carbonate minerals and trace element and rare earth element (REE) compositions of the iron-formations.

NASA Discipline Number 52-30↗
NASA NTRS1983

Literature relevant to remote sensing of water quality

References relevant to remote sensing of water quality were compiled, organized, and cross-referenced. The following general categories were included: (1) optical properties and measurement of water characteristics; (2) interpretation of water characteristics by remote sensing, including color, transparency, suspended or dissolved inorganic matter, biological materials, and temperature; (3) application of remote sensing for water quality monitoring; (4) application of remote sensing according to water body type; and (5) manipulation, processing and interpretation of remote sensing digital water data.

Middleton, E. M.↗
NASA NTRS2003

BENCAL Cruise Report

This report documents the scientific activities on board the South African Fisheries Research Ship (FRS) Africana during an ocean color calibration and validation cruise in the Benguela upwelling ecosystem (BEN-CAL), 4-17 October 2002. The cruise, denoted Afncana voyage 170, was staged in the southern Benguela between Cape Town and the Orange River within the region 14-18.5 deg E,29-34 deg S, with 15 scientists participat- ing from seven different international organizations. Uniquely in October 2002, four high-precision ocean color sensors were operational, and these included the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Aqua and Terra spacecraft, the Medium Resolution Imaging Spectrometer (MERIS), and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). SeaWiFS imagery was transmitted daily to the ship to assist in choosing the vessel's course and selecting stations for bio-optical deployments. There were four primary objectives of the cruise. The first was to conduct bio-optical measurements with above- and in-water optical instruments to vicariously calibrate the satellite sensors. The second was to interrelate diverse measurements of the apparent optical properties (AOPs) at satellite sensor wavelengths with inherent optical properties (IOPs) and bio-optically active constituents of seawater such as particles, pigments, and dissolved compounds. The third was to determine the interrelationships between optical properties, phytoplankton pigment composition, photosynthetic rates, and primary production, while the fourth objective was to collect samples for a second pigment round-robin intercalibration experiment. Weather conditions were generally very favorable, and a range of hyperspectral and fixed wavelength AOP instruments were deployed during daylight hours. Various IOP instruments were used to determine the absorption, attenuation, scattering, and backscattering properties of particulate matter and dissolved substances, while a Fast Repetition Rate Fluorometer (FRRF) was deployed to acquire data on phytoplankton photosynthetic activity. Hydrographic profiling was conducted routinely during the cruise, and seawater samples were collected for measurements of salinity, oxygen, inorganic nutrients, pigments, particulate organic carbon, suspended particulate material, and primary production. Location of stations and times of optical deployments were selected to coincide with satellite overpasses whenever possible, and to cover a large range in trophic conditions.

Hooker, Stanford B.↗
NASA NTRS1986

Emission of methane and other trace gases from the Amazon Varzea

Researchers measured the distributions and fluxes of methane and other trace gases from the various Amazon floodplain environments. These were determined during both a large scale, quasi-synoptic survey along a 2000 km reach of the Amazon river and an intensive local study (by J. Melack, R. Harriss et al.) covering a six-week period. The environments studied included the major rivers, connecting channels (paranas), floating macrophyte beds, flooded forests, open lakes and recently wetted soils. The results are summarized. Measured rates of methane emission averaged about 300 mg m-2 d-1, but with considerable variance, and were comparable to or higher than previously reported emissions from similar temperature zone environments. In general, areas covered by floating macrophytes showed the highest emissions. Individual hotspots had among the highest rates ever observed, over 10 g m-2 d-1. The high methane emissions appear to result because about 50% of the organic matter fixed on the floodplain (either terrestrial or aquatic) that is oxidized in the water is decomposed anaerobically via methanogensis. Measured fluxes of methane to the atmosphere appear to be significantly correlated with surface water dissolved methane concentrations.

Richey, Jeffrey E.↗
NASA NTRS1999

Ocean Color Data at the Goddard DAAC

The apparent color of the ocean is determined by the interactions of incident light with substances or particles present in the water. The most significant constituents are free-floating photosynthetic organisms (phytoplankton) and inorganic particulates. Phytoplankton contain chlorophyll, which absorbs light at blue and red wavelengths and transmits in the green. Particulate matter can reflect and absorb light, which reduces the clarity (light transmission) of the water. Substances dissolved in water can also affect its color. Observations of ocean color from space, utilizing sensors specially designed to detect the small amount of light radiating from the sea surface, provide a global picture of the patterns of biological productivity in the world's oceans. For that reason, ocean color remote sensing data is a vital resource for biological oceanography. Unlike the limited area of the ocean that can be investigated from a research ship, data from a satellite sensor covers a large region and provides a comprehensive view of the marine environment.

Source record↗
NASA NTRS1992

Environmental factors controlling fluxes of dimethyl sulfide in a New Hampshire fen

The major environmental factors controlling fluxes of dimethyl sulfide (DMS) in a Sphagnum-dominated peatland were investigated in a poor fen in New Hampshire. DMS emissions from the surface of the peatland varied greatly over 24 hours and seasonally. Maximum DMS emissions occurred in summer with minima in the late fall. Temperature was the major environmental factor controlling these variabilities. There was also some evidence that the changes in water table height might have contributed to the seasonable variability in DMS emission. The influence of the water table was greater during periods of elevated temperature. DMS and MSH were the most abundant dissolved volatile sulfur compound (VSC) in the surface of the water table. Concentrations of dissolved VSC's varied with time and space throughout the fen. Dissolved MDS, MSH, and OCS in the surface of the water table were supersaturated with respect to their concentrations in the atmosphere suggesting that the peat surface was a source of VSC's in the peatland. VCS in peatlands seemed to be produced primarily by microbial processes in the anoxic surface layers of the peat rich in organic matter and inorganic sulfide. Sphagnum mosses were not a direct source of VSC's. However, they increased transport of DMS from the peat surface to the atmosphere.

Demello, William Zamboni↗
NASA NTRS1982

Literature review of organic matter transport from marshes

A conceptual model for estimating a transport coefficient for the movement of nonliving organic matter from wetlands to the adjacent embayments was developed in a manner that makes it compatible with the Earth Resources Laboratory's Productive Capacity Model. The model, which envisages detritus movement from wetland pixels to the nearest land-water boundary followed by movement within the water column from tidal creeks to the adjacent embayment, can be transposed to deal with only the interaction between tidal water and the marsh or to estimate the transport from embayments to the adjacent coastal waters. The outwelling hypothesis postulated wetlands as supporting coastal fisheries either by exporting nutrients, such as inorganic nitrogen, which stimulated the plankton-based grazing food chain in the water column, or through the export of dissolved and particulate organic carbon which provided a benthic, detritus-based food web which provides the food source for the grazing food chain in a more indirect fashion.

Dow, D. D.↗
NASA NTRS1991

Sedimentary organic molecules: Origins and information content

To progress in the study of organic geochemistry, we must dissect the processes controlling the composition of sedimentary organic matter. Structurally, this has proven difficult. Individual biomarkers can often be recognized, but their contribution to total organic materials is small, and their presence does not imply that their biochemical cell mates have survived. We are finding, however, that a combination of structural and isotopic lines of evidence provides new information. A starting point is provided by the isotopic compositions of primary products (degradation products of chlorophylls, alkenones derived from coccoliths). We find strong evidence that the isotopic difference between primary carbonate and algal organic material can be interpreted in terms of the concentration of dissolved CO2. Moreover, the isotopic difference between primary and total organic carbon can be interpreted in terms of characteristic isotopic shifts imposed by secondary processes (responsive, for example, to O2 levels in the depositional environment. In favorable cases, isotopic compositions of a variety of secondary products can be interpreted in terms of flows of carbon, and, therefore, in terms of specific processes and environmental conditions within the depositional environment.

Hayes, J. M.↗
NASA NTRS1994

Predictive isotopic biogeochemistry: hydrocarbons from anoxic marine basins

Carbon isotopic compositions were determined for individual hydrocarbons in water column and sediment samples from the Cariaco Trench and Black Sea. In order to identify hydrocarbons derived from phytoplankton, the isotopic compositions expected for biomass of autotrophic organisms living in surface waters of both localities were calculated based on the concentrations of CO2(aq) and the isotopic compositions of dissolved inorganic carbon. These calculated values are compared to measured delta values for particulate organic carbon and for individual hydrocarbon compounds. Specifically, we find that lycopane is probably derived from phytoplankton and that diploptene is derived from the lipids of chemoautotrophs living above the oxic/anoxic boundary. Three acyclic isoprenoids that have been considered markers for methanogens, pentamethyleicosane and two hydrogenated squalenes, have different delta values and apparently do not derive from a common source. Based on the concentration profiles and isotopic compositions, the C31 and C33 n-alkanes and n-alkenes have a similar source, and both may have a planktonic origin. If so, previously assigned terrestrial origins of organic matter in some Black Sea sediments may be erroneous.

Non-NASA Center↗
NASA NTRS1993

The anaerobic degradation of organic matter in Danish coastal sediments - Iron reduction, manganese reduction, and sulfate reduction

A combination of porewater and solid phase analysis as well as a series of sediment incubations are used to quantify organic carbon oxidation by dissimilatory Fe reduction, Mn reduction, and sulfate reduction, in sediments from the Skagerrak (located off the northeast coast of Jutland, Denmark). Solid phase data are integrated with incubation results to define the zones of the various oxidation processes. At S(9), surface Mn enrichments of up to 3.5 wt pct were found, and with such a ready source of Mn, dissimilatory Mn reduction was the only significant anaerobic process of carbon oxidation in the surface 10 cm of the sediment. At S(4) and S(6), active Mn reduction occurred; however, most of the Mn reduction may have resulted from the oxidation of acid volatile sulfides and Fe(2+) rather than by a dissimilatory sulfate. Dissolved Mn(2+) was found to completely adsorb onto sediment containing fully oxidized Mn oxides.

Canfield, Donald E.↗
NASA NTRS1993

Molecular and bulk isotopic analyses of organic matter in marls of the Mulhouse Basin (Tertiary, Alsace, France)

Contents of 13C in kerogens and carbonates in 21 samples from a core of the MAX borehole, Mulhouse Evaporite Basin, range from -27.3 to -23.5 and -3.7 to -1.8% vs PDB, respectively. Organic nitrogen in the same samples is enriched in 15N relative to atmospheric N2 by 12.2-15.7%. Hydrogen indices and delta values for kerogens vary systematically with facies, averaging 493 mg HC/g Corg and -25.7% in the most saline facies (dominated by inputs from aquatic sources) and 267 mg HC/g Corg and -23.7% in the least saline facies (50/50 aquatic/terrigenous). Values of delta were measured for individual aliphatic hydrocarbons from three samples representing three different organic facies. For all samples, terrigenous inputs were unusually rich in 13C, the estimated delta value for bulk terrigenous debris, apparently derived partly from CAM plants, being -22.5%. In the most saline facies, isotopic evidence indicates the mixing of 13C-depleted products of photosynthetic bacteria with 13C-enriched products of halotolerant eukaryotic algae. At lower salinities, a change in the producer community is marked by a decrease in the 13C content of algal lipids. The content of 13C in algal lipids increases in the least saline facies, due either to succession of different organisms or to decreased concentrations of dissolved CO2.

NASA Discipline Exobiology↗