The shot-sensor method of measuring currents in shallow estuarine waters

A current measuring device, the Shot-Sensor, was developed as a low cost alternative to measuring water flow speeds and directions using conventional, more expensive instrumentation. The device releases stainless steel shot of known size and settling speed into a flowing water mass. As the shot settles, it is dispersed by currents and ends up in settling traps. Mean current speed and direction can be calculated from the patterns of dispersal and the percentages of shot of various sizes in the traps. Determination of precision and accuracy indicate that the Shot-Sensor can measure within a few cm s^?1 of more expensive meters and may be suitable for some shallow-water applications. Speed range of the Shot-Sensor is presently limited between 3 and 40 cm s^?1, but further development could allow this range to be extended.     

Silver in San Francisco Bay estuarine waters

Spatial gradients of silver concentrations in the surface waters of San Francisco Bay reveal substantial anthropogenic perturbations of the biogeochemical cycle of the element throughout the estuarine system. The most pronounced perturbations are in the south bay, where dissolved (<0.45 μm) silver concentrations are as high as 250 pM. This is more than one order-of-magnitude above baseline concentrations in the northern reach of the estuary (6 pM) and approximately two orders-of-magnitude above natural concentrations in adjacent coastal waters (3 pM). The excess silver is primarily attributed to wastewater discharges of industrial silver to the estuary on the order of 20 kg d^?1. The contamination is most evident in the south bay, where wastewater discharges of silver are on the order of 10 kg d^?1 and natural freshwater discharges are relatively insignificant. The limited amount of freshwater flushing in the south bay was exacerbated by persistent drought conditions during the study period. This extended the hydraulic residence time in the south bay (≥160 d), and revealed the apparent seasonal benthic fluxes of silver from anthropogenically contaminated sediments. These were conservatively estimated to average ≈16 nmol m^?2 d^?1 in the south bay, which is sufficient to replace all of the dissolved silver in the south bay within 22 d. Benthic fluxes of silver throughout the estuary were estimated to average ≈11 nmol m^?2 d^?1, with an annual input of approximately 540 kg yr^?1 of silver to the system. This dwarfs the annual fluvial input of silver during the study period (12 kg yr^?1) and is equivalent to approximately 10% of the annual anthropogenic input of silver to the estuary (3,700–7,200 kg yr^?1). It is further speculated that benthic fluxes of silver may be greater than or equal to waste water fluxes of silver during periods of intense diagenic remobilization. However, all inputs of dissolved silver to the estuary are efficiently sorbed by suspended particulates, as evidenced by the relatively constant conditional distribution coefficient for silver throughout the estuary (K_d≈10⁵).     

Sulfate enrichments in estuarine waters of North Carolina

Sulfate concentrations in the mesohaline surface waters of the Pamlico and Neuse River estuaries were enriched, relative to the conservative seawater ratio with Cl^? (0.0517 (M)), by 5 to 43% between late winter and early summer. During this period, sulfate concentrations increased to a maximum excess of 3.5 mM in the bottom waters (0.5 m deep) through intermittent periods of both very low river flow and bottom water anoxia. The calculated net sulfate production rate for this period was 18 mmol per m² per d in the bottom waters. By late summer, the excess sulfate (an average of 12 mol per m²) had been removed from the water column, presumably due to SO₄ ^?2 reduction in anoxic bottom waters and sediments. Qualitative laboratory experiments with slurries of mud exposed to excess O₂ and treated with inhibitors of cytochrome oxidase showed that it was possible to produce the excess SO₄ ^?2 under these conditions via biochemical (not chemical) oxidation of pyride that occurs within the top 5 cm of mud (ca. 100 mmol pyrite-S per g dry mud). Whether the in situ substrate for SO₄ ^?2 production was pyrite, S⁰, or S⁺², is unknown, but the predominance of aqua regia extractable pyrite-Fe and the accumulation of excess SO₄ ^?2 in slurries with insufficient other sources of oxidizable S, indicates that it may be an important substrate for biochemical production of SO₄ ^?2.     

On the use of the nephelometer in estuarine waters

A study of the problems encountered in nephelometric determinations of suspended sediment loads in the Chesapeake Bay estuary has led to development of a technique which uses nephelometer readings as a guide for sampling at vertical profiles in an estuary. This permits optimum sampling for concentration profiles and allows one to use nephelometer/load ratios to characterize particles.     

Detoxification of chlorinated sewage effluent by dechlorination in estuarine waters

Secondary treated sewage was chlorinated to a residual level of 2–10 mg/l in a continuous flow system in the laboratory and diluted to various levels with estuarine water. A portion of the chlorinated sewage effluent was dechlorinated with sodium thiosulfate and the dechlorinated waste was diluted with estuarine water in the same proportions as the chlorinated waste.Menidia menidia, Palaemonetes pugio andCrassostrea virginica were exposed to chlorinated and dechlorinated treatments. High concentrations of chlorinated effluent caused mortalities inM. menidia andP. pugio, whereas similar concentrations of dechlorinated wastes did not cause mortalities. Mortalities in the chlorinated waste are correlated with chlorine residuals. Similarly, the chlorinated wastes depressed the shell deposition rate ofC. virginica below 50% of controls at all doses. Dechlorinated waste allowed shell deposition greater than 50% of controls. However, the occurrence of some growth inhibition inC. virginica exposed to dechlorinated waste suggests the presence of toxic material in the waste other than chlorine.     

Removal of dissolved boron and silicon during estuarine mixing of sea and river waters

The behaviour of dissolved boron and silicon during mixing of sea and river waters has been studied in two surveys of the estuary of the River Alde in Suffolk, England. Removal of approximately 25–30 per cent was found for both elements. This appears to be the first report of estuarine removal of dissolved boron. The extent of removal of silicon in the Alde is somewhat higher than that found in other estuaries.     

Early diagenesis of fatty acids and isoprenoid alcohols in estuarine and coastal sediments

Fatty acids and isoprenoid alcohols were analyzed in river, estuarine, and coastal sediment cores: (1) to investigate the distribution of these lipids among the unbound phase. those bound or closely associated with humic substances, and those bound or closely associated with the huminkerogen and clay mineral matrix. (2) to investigate the diagenetic changes of these lipids with depth in the sediments. and (3) to obtain information on the use of these compounds as organic tracers in marine sediments.Results confirm earlier observations that fatty acids are rapidly altered in marine sediments Both the total and the individual fatty acids decrease in concentration with depth in the sediments: unsaturated acids decrease faster than saturated acids and unbound acids decrease faster than bound acids Approximately 8–62% of the fatty acids were unbound. 2–22% were associated with humic substances. and 38–86% were associated with the residual organic-mineral matrix. Qualitative differences also exist between the fatty acids associated with the unbound, humic, and residual fractions. The ratio of trans/cis geometric isomers of the fatty acids generally increases downcore. with no rearrangement of the double bond positions within the molecules. Either the cis isomer is being preferentially degraded with depth in the sediments, or there is a low temperature, clay catalyzed conversion of the cis isomers to the trans isomers occurring down the cores.Phytol was the major alcohol present in the sediments and does not appear to be altered as rapidly as the fatty acids. Less than 10% of the total phytol (PHY) plus dihydrophytol (DHP) was present as DHP and no trend could be discerned between PHY and DHP with depth or with unbound, humic, and residual material in the cores. All of the isolated DHP appeared to be present as the RRR stereoisomer. Along with the absence of phytane in the cores, this observation suggests that the reduction of phytol to dihydrophytol is microbially mediated in the upper layer of the sediment.     

Survival of F-RNA coliphages and three bacterial indicators during wastewater chlorination and transport in estuarine waters

Three bacterial water quality indicators,Clostridium perfringens, enterococci, and fecal coliforms, were compared to F-RNA coliphages for their survival during chlorination at several municipal wastewater treatment plants in Rhode Island and seasonally during transport in a section of the Narragansett Bay estuary. F-RNA coliphages were used as the best available indicator for the survival of Noroviruses (formerly Norwalk-like virus), the most frequently identified agent for the most prevalent waterborne disease (an acute but benign gastroenteritis), which has yet to be propagated in tissue culture and for which there is no lower animal model. Inactivation of the enterococci and fecal coliforms during wastewater chlorination was much greater than that of the F-RNA coliphages whose inactivation was essentially the same as that of C.perfringens. Survival of the F-RNA coliphages andC. perfringens during winter transport down Narragansett Bay were comparable to each other and greater than that for the enterococci or fecal coliforms. During the summer,C. perfringens survived longer than the other three indicators, possibly because the virus-like (F-RNA coliphages) and the two vegetative bacterial indicators were more susceptible than theC. perfringens spores to the lethal effects of sunlight and elevated water temperatures during the summer. Based on these findings, F-RNA coliphages seems to be a reliable indicator of viral contamination and die-off in estuarine waters.     

The Baltic-Kattegat-Skagerrak estuarine system

Measurements of alkalinities and calcium concentrations in the Baltic Sea indicate that there has been a slight increase in both these parameters over the last century. These increases may have been caused by the leaching of limestone by acid rain. About ten percent of the nutrients are exported from the Baltic to the Kattegat; however, very little, if any, alkalinity is stored in the Baltic since river input and system output are approximately equal. Since the precipitation and evaporation are almost equal in the Baltic Sea, corrections are not needed for river inputs.     

The role of bioindicators in estuarine management

Estuarine organisms can be considered three ways as bioindicators—first, as indicators of a defined set of environmental conditions, second, as indicators of contaminant loads on the system, and third, as indicators of the overall health of the system. By their very nature, estuarine organisms are eurytolerant and this, along with the various stratagems that have evolved to cope with the problems of life in estuaries results in a confusing picture for the estuarine manager. The recommended bioindicators for estuarine conditions are plankton; for contaminant loads, a range of species with different feeding types; and for system status, a eurytolerant species, such as the musselMytilus edulis for laboratory monitoring or a “target” species such as the clamMacoma balthica for field monitoring. However, it would be unwise to rely on a single indicator, and the recommendation is that the final choice, and preferably choices, be tailored to the desired goal.     

Rapid quantification of humic and fulvic acids by HPLC in natural waters

A simple method based on high-performance size-exclusion chromatography (HPSEC) has been developed for rapid quantification of humic and fulvic acids (HA and FA) in stream waters. A Tsk-gel column was used to separate natural dissolved organic matter (DOM) into two components: peak A and B. In terms of HPSEC chromatograms and fluorescence patterns, peak A and B were similar to the corresponding XAD-extracted HA and FA, respectively. It is suggested that peak A fraction mainly consisted of HA, and peak B fraction FA. The similar separation of HA and FA using HPSEC and a conventional XAD method suggests the consistency of molecular size distribution and physical–chemical properties of DOM. HPSEC offers a simple and rapid method for the quantification of HA and FA instead of tedious extractions of humic substances. Analyses of natural water samples show that the calculation of HA/FA based on UV absorbance was under- or over-estimated, the calibration using the extracted HS allows a more accurate quantification. The fast screening of HA and FA provides useful quantitative and qualitative information that can be used in environmental or monitoring studies.     

Dissolved free amino acids in interstitial waters of Georgia salt marsh soils

The patterns of concentration of dissolved free amino acids (DFAA) are different and more variable in pore water of soils from a Georgia salt marsh than in most surface waters. Elevated concentrations of DFAA (up to 8850 nmoles liter^?1) and high relative levels of alanine and glutamic acid suggest that bacteria may produce these amino acids. In addition to the common protein amino acids, an unidentified compound was present and was the dominant free amino acid in some sections. This compound appeared to be specific to pore waters as it was not observed in surface waters or in hydrolysates of sediments, bacteria or plants from the marsk.     

Determination of naphthenic acids in crude oil by chemical ionization mass spectrometry

Naphthenic acids in petroleum are considered a class of biological markers. Their potential use in source correlation and as an indicator of biodegradation was reported in the past ( Dzidic et al. ,1988 ; Behar and Albrecht, 1984). Due to their highly complicated properties, detailed characterization of the acids is difficult. A method based on positive ion CI (chemical ionization) mass spectrometry using isobutane reagent gas to produce ( M 15)^ ions was applied to the analysis of naphthenic acid esters. Since the complex mixture of naphthenic acids cannot be separated into individual components, only the determination of relative distribution of acids classified in terms of hydrogen deficiency was possible. The identities and relative distribution of fatty and mono-, di-, tri-, and higher polycyclic acids were obtained from the intensities of the ( M 15 )^ ions according to z-series formula CπH2π 2 O2 of naphthenic acids. The components are characterized on the basis of group type and carbon number distributions. A comparison of the FAB and CI results showed that the group type distributions obtained bv both methods agree surprisingly well.The results indicated this method is simple, rapid and easy to operate. The geochemical implication of naphthenic acids was investigated by using a set of well-characterized crude oil samples. It is found that the naphthenic acid distribution can be used as a fingerprint for oil-oil and oil-source correlations.     

CPMAS 13C NMR spectra of estuarine sedimentary humic acids

CPMAS ¹³C NMR spectra of two estuarine sedimentary humic acids were recorded on a Bruker WP-SY 200 spectrometer. Both samples were found to contain similar aromatic and aliphatic carbon fractions. The sedimentary humic acids have unusually high methoxyl contents and more than one type of methoxyl is indicated. The high methoxyl content may be related to relatively low values for estuarine sedimentary humic acid-metal complexes. Carbohydrate contents of the humic acid samples were also found to be low.     

Dissolved organic carbon and volatile fatty acids in marine sediment pore waters

The results of a study of the contribution of microbial metabolic products to total dissolved organic carbon (DOC) levels in coastal sediments are presented. The data indicate that acidic volatile compounds make up a substantial fraction of pore water DOC's in both oxic and anoxic pore waters of coastal marine sediments. Formic, acetic and butyric acids are the principal volatile species identified at levels exceeding 10 μM. Acid concentrations are up to five times higher in anoxic pore waters than in oxic waters. Volatile organic acids show promise as indicators of diagenetic processes in marine sediments and of the ecological succession of microorganisms, in particular.     

Concentrations,physico-chemical states and mean residence times of 210Pb and 210Po in marine and estuarine waters

The concentrations and physico-chemical states of ²¹⁰Pb have been measured in Bikini Atoll and Washington State coastal waters, and ²¹⁰Po in Washington coastal waters. Lead-210 concentrations of 113–133 dpm · m^?3 were found in surface water collections near Bikini Atoll and 29–153 dpm · m^?3 in Bikini Lagoon. The concentrations of ²¹⁰Pb in near Bikini and in Washington State waters increased with depth in the upper 150m at a rate of 0.35–0.45dpm·m^?3 · m^?1. In the North Equatorial Current waters near Bikini Atoll ²¹⁰Pb was found associated predominantly with the soluble (colloidal) fraction, but in Washington coastal waters ²¹⁰Pb and ²¹⁰Po were found associated with the paniculate (> 0.3 μm) fraction. The mean residence times of ²¹⁰Pb, calculated from the atmospheric input to marine waters from precipitation and the concentrations measured in surface water, were consistent with the physico-chemical states of ²¹⁰Pb found in samples collected in deep ocean and coastal waters. Approximate values of the mean residence times were calculated, for the upper 50 m, to be as follows: 58 days in the Strait of Juan de Fuca, 128 days at the 5-mile (8 km) station off Cape Flattery (Washington), 163 days at the 12-mile (19 km) station off Cape Flattery, and 2.6 yr near Bikini Atoll. It appears that ²¹⁰Pb and ²¹⁰Po can be used to trace particle removal rates in the upper layers of marine waters.     

The regulation of trace element concentrations in river and estuarine waters contaminated with acid mine drainage: The adsorption of Cu and Zn on amorphous Fe oxyhydroxides

The partition of Cu and Zn between the particulate and dissolved phases has been investigated in the Carnon River and Restronguet Creek, England; a system contaminated by acid mine drainage. It is shown that binding to the surfaces of amorphous Fe oxyhydroxides regulates Cu and Zn concentrations in solution, in both fresh and saline waters. The sorptive process is pH dependent and is in general agreement with laboratory studies of trace metal adsorption on amorphous Fe oxyhydroxides.     

The macroinfaunal community of a tropical estuarine lagoon

The benthic macroinfauna of Lagunal Joyuda, a coastal lagoon in Puerto Rico, was surveyed for two years. Seven hundred fifty core samples yielded 23 macrobenthic taxa. The oligochaeteThalassodrilides gurwitschi comprised 43.4% of the number of individuals collected. Polychaetes comprised 35.4% of the individuals, includingCapitella cf.capitata, Dasybranchus lumbricoides, andSteninonereis martini in approximately equal numbers. The amphipodGrandidierella bonnieroides made up 11.5% of the community. The lagoon yielded fewer species than other tropical estuaries in the Caribbean and Atlantic, but the trophic composition, mostly deposit feeders, was similar. Seasonal patterns in the abundance of individuals were most pronounced in the central basin, with maximum number of organisms during the wet season, and a minimum in the dry season. Responses to rainfall events, however, were variable and probably related to migration patterns in predators. Macrofaunal biomass demonstrated a high degree of annual variation at all sampling stations with a marked increase in 1987. Low macrofaunal biomass, lack of temporal association with physical-chemical conditions, and inverse relationships with predator populations suggest that patterns of macrofaunal abundance in Laguna Joyuda are mediated primarily by biotic mechanisms. *** DIRECT SUPPORT *** A01BY050 00006     

Aquathermolysis of humic and fulvic acids: Simulation of organic matter maturation in hot thermal waters

Dissolved aromatic compounds in Hungarian thermal waters were first reported more than 10 years ago. Among the identified compounds were alkylbenzene, polyaromatic hydrocarbon and heteroaromatic homologue series. The appearance of dissolved organic compounds has been bound to a threshold temperature of ∼80 °C, and their distribution is controlled by the water temperature. Relative demethylation and aromatisation were observed with increasing temperature. The origin of these compounds is not proved. Among precursor candidates are humic substances.Simulation experiments were carried out on humic and fulvic acid and on their mixture to gain information on aromatic compounds formed. The samples were heated and products were measured with GC-MS.In the presence of oxygen, increasing concentration of benzene can be observed as a function of temperature. Toluene and thiophene can be identified, other alkylbenzenes are missing. Under reductive conditions the concentration of benzene, toluene and the ratio of short to long chained aromatics generally increases in every sample as a function of temperature. Main compounds are toluene and benzene. The amount of heteroaromatic compounds increases with temperature, but their relative concentration compared to aromatic hydrocarbons decreases. At higher temperatures the proportion of pyrroles drops and S and O containing ones become dominant.The different processes (formation, aromatisation, polycondensation, relative demethylation, decomposition) occur in parallel but their relative intensities vary as a function of temperature. The effects of duration and increasing temperature are similar but not equal: both demethylation and aromatisation can be observed.