Brackish Water Systems Research Articles

Paleosalinities in ancient brackish water systems determined by 87Sr/ 86Sr ratios in carbonate fossils: A case study from the Western Canada sedimentary basin

Two strategies for determining paleosalinities in ancient brackish water deposits are presented based on the 87 Sr/ 86 Sr ratios in well preserved carbonate fossil shells. The relative contributions of seawater and freshwater can be determined for shells of unknown or presumed ecological affinity by comparing their 87 Sr/ 86 Sr ratios to contemporaneous marine and fluviatile sources. The nearly one hundredfold difference in Sr concentration between seawater (7.7 ppm) and freshwater (median = 0.071 ppm) dictates that mixing relations define hyperbolae. Paleosalinities are most precisely determined along the freshwater asymptote (<15‰) because these waters have the lower Sr concentration, and, therefore, display the greatest rate of change of 87 Sr/ 86 Sr with salinity. Paleosalinities greater than 15‰ are resolvable if the 87 Sr/ 86 Sr or Sr concentration in the freshwater mixing endmember is greater than the 50th percentile for present-day Sr concentrations in world rivers and lakes. A second technique utilizes both 87 Sr/ 86 Sr and Sr/Ca from a single fossil species and allows the brackish water hypothesis to be tested graphically on a plot of 87 Sr/ 86 Sr— Ca/Sr. Linear correlations on this plot are evidence for two-component mixing. Measured Sr/Ca in mollusc shells are related to the original Sr/Ca in the habitat waters by a species specific Sr distribution coefficient ( D Sr ). For the case of seawater-freshwater mixing, D Sr is fixed in that seawater must plot on the water mixing line. If the transformation between shell and water mixing lines yields a D Sr within the range of modern values (0.2–0.3), a brackish water habitat is implied. Examples from purported brackish water deposits of the early Cretaceous Mannville Group, Canada, illustrate the potential uses of 87 Sr/ 86 Sr, Sr, and Sr/Ca for determining paleosalinities in ancient estuarine and estuarine-like deposits, and the importance of the paleohydrological perspective as a factor influencing the interpretation of ancient depositional environments.

A Critical Appraisal of the Application of Guélorget and Perthuisot's Concepts of the Paralic Ecosystem and Confinement to Macrotidal Europe

The concepts of the 'paralic ecosystem' and 'confinement' put forward by Guélorget and Perthuisot (and collaborators), on the basis of studies of the Mediterranean coast, are summarized and then discussed in relation to the estuaries and lagoons of macrotidal Europe. It is concluded that 'confinement' is only marginally applicable to brackish-water systems in macrotidal regions.

Diseases and Injuries Associated with Mortality of Hatchery Reared Baltic Cod (Gadus morhua L.) Larvae

A cod hatching plant was established in 1992 on the island of Bornholm in the Baltic Sea in order to elucidate the possibilities for restocking of cod fry in this brackishwater system. The disease prevalence in 3 batches of hatchery-reared yolksac larvae from the Baltic cod (Gadus morhua L.) was monitored during the posthatch period. High prevalences of bacteriosis/mycosis, lordosis/scoliosis, injuries and protozoan endoparasitism were recorded. Vibrio sp. and Vibrio anguillarum serovar 04, 06, 08 in addition to nontypable strains and saprolegniaceous fungi were isolated from the larvae. The dinoflagellate-like endoparasites were located in the yolksac of the cod larvae.

Metabolite production rates from Atlantic salmon ( Salmo salar L.) and Arctic char ( Salvelinus alpinus L.) reared in single pass land-based brackish water and sea-water systems

Metabolite production rates of several groups of Atlantic salmon (60 g and 2000–4000 g) and of Arctic char (47–70 g) kept in seawater or brackish water in single pass, land-based rearing units, were examined. The metabolites measured were total nitrogen, ammonia, urea and total phosphorus. For fish fed on a continuous light and feeding regime, the daily variation in metabolite production rates was small. Typical daily variation patterns were found for the ammonia production rates, but not for urea, for fish fed between 08.00 and 20.00 hours. For these fish, the average ammonia production rate during the day seemed to occur between 15.00 and 16.00 hours. The average percentages of total nitrogen excreted as total ammonia were in the range 61–67%, while 7–10% were excreted as urea. The average production rates (mg Nitrogen/(kg fish min)) of total nitrogen, total ammonia and urea increased linearly with increasing specific growth rate under the experimental conditions used. The production rates of total ammonia, when expressed as g/kg food, decreased with increasing conversion factor. The structural relationship between ammonia production and conversion factor is also accounted for theoretically.

Initial fouling of nontoxic coatings in fresh, brackish, and sea water

AbstractObjectives of this project were to evaluate benefits — over the short term — that might derive from control of the surface properties of materials used in energy transfer devices; and to identify preferred ranges of surface parameters that might be specified to minimize deposits of biological fouling known to deteriorate energy exchange efficiencies in seawater, brackish water, and freshwater systems. By modifying the surface chemistry and surface energy of test plates with very thin coatings (nontoxic) and examining the acquired films at various time intervals, the earliest events of biofouling caused by macromolecules and microbial organisms were defined. Overall, the results were remarkably similar for all systems tested in showing that deliberate modification of the initial material surface qualities can significantly reduce the retention of biofouling layers.

Uptake and release of petroleum hydrocarbons by two brackish water bivalves,Mytilus edulisL. andMacoma baltica(L.)

Abstract The uptake and release patterns of PHC (petroleum hydrocarbon) refinery waste water in low level concentrations (maximum total PHC concentration = 176μg·1-1) by the two bivalves Mytilus edulis L. and Macoma baltica (L.) have been investigated (GC and fluorescence spectrophotometric analyses) in an experimental outdoor flow through basin. Mytilus edulis showed a short period of fast uptake (maximum total PHC concentration = 109μg·g-1 wet weight) and a fast initial release followed by a longer period of slow release. Macoma baltica showed a slower and more extended uptake (maximum total PHC concentration = 73μg·g-1 wet weight) and release pattern probably due to its feeding behaviour, lower respiration rate indicating a slower metabolism and possibly lower PHC-metabolizing activity. We conclude that in many situations, especially in brackish water systems, the physiology, behaviour and distribution of Macoma baltica make it an alternative monitoring organism to the more commonly used Mytilus edulis.

Effect of the surfactant Corexit 7664 on uptake of cadmium by organisms and biological matter in a closed circulated brackish-water system

Juvenile flounder and common mussel from the Baltic Sea were kept in Corexit 7664 (50 µg/l) and cadmium (5 µg/l)-contaminated, recirculated, sea-water systems for 200 days at 15 °C and 20 ‰ S. Accumulation of cadmium with exposure time was measured in several fish tissues and in mussel. There were no differences in the cadmium accumulation by tissues with or without the addition of Corexit 7664. No acute effects of the contaminants on the experimental animals could be noted. Final cadmium concentrations, reached for all biological matter analysed, were 4 times higher than in full-strength sea water.

Effect of the surfactant Corexit 7664 on uptake of cadmium by organisms and biological matter in a closed circulated brackish-water system [was essentially nil] : von Westernhagen, H. and V. Dethlefsen, 1982. Helgoländer Meeresunters., 35(1):1–12. Biol. Anstalt Helgoland (Zentrale), Notkestr. 31, D-2000 Hamburg 52, FRG

Effect of the surfactant Corexit 7664 on uptake of cadmium by organisms and biological matter in a closed circulated brackish-water system [was essentially nil] : von Westernhagen, H. and V. Dethlefsen, 1982. Helgoländer Meeresunters., 35(1):1–12. Biol. Anstalt Helgoland (Zentrale), Notkestr. 31, D-2000 Hamburg 52, FRG

The Diatom Flora of the Lower Chevelon Creek Area of Arizona: An Inland Brackish Water System

The Diatom Flora of the Lower Chevelon Creek Area of Arizona: An Inland Brackish Water System

Oncolites in Cretaceous Yucca Formation, Presidio County, Texas: ABSTRACT

Detailed stratigraphic work in the Yucca Formation, Presidio County, Texas, has revealed about 70 ft (21 m) of oncolite-bearing strata. The zone of oncolite occurrence is 180 ft (55 m) above the unconformity separating the Permian and Cretaceous rocks and 665 ft (203 m) below the initial occurrence of abundant Orbitolina. The zone varies both vertically and laterally from oncolite-supported conglomerate with micrite matrix to micrite with less than 10% oncolite content, to algal-encrusted, matrix-supported pebble conglomerate. Oncolites range from less than 0.5 in. (1.25 cm) to approximately 3 in. (7.5 cm) in diameter, and are commonly size sorted within the zone. The oncolites are most commonly nucleated about a fragmental piece of oncolite material and are classified as type-SS. In the pebble conglomerate facies, algal encrustations occur on very well-rounded, spheroidal clasts of siltstone, micrite, and chert. Very rare encrustations are present on clasts appreciably larger or smaller than the pebble size. Rarely is the algal material nucleated about organic remains such as pelecypod, gastropod, or brachiopod shells. The presence of this oncolite zone within an otherwise unfossiliferous section provides some control for interpreting depositional environments within the Yucca Formation. However, oncolites have been reported from several aquatic depositional environments both in the geologic record and as forming today. These environments include: lacustrine, fluvial; shallow, nearshore marine; and marginal marine brackish water systems. Local sedimentary features and broader stratigraphic relations effectively eliminate lacustrine and fluvial interpretation. End_of_Article - Last_Page 760------------

Hydraulic turbine energy recovery - R.O. System

In reverse osmosis desalination plants large flow rates of concentrated brine are discharged at high pressure from the membrane modules. Currently this pressure energy is wasted. This paper reviews the impact of soaring energy costs on the technical alternative of hydraulic turbine energy recovery. The capital costs, operating costs, and economics in electrical energy are evaluated for both sea-water and brackish water systems. Schemes of hydraulic turbine coupled with electric generator, tied to the electric power supply are considered for various plant sizes from 1 to 10 mgd. The analysis, in parametric form, presents the interrelationships between the cost of money, cost of electrical energy, and recovery factors for the different plant sizes and for sea-water and brackish water systems. The results will serve as a guide to determine when such a power recovery system should be seriously considered and evaluated in greater details for specific applications.

Design and operation of 800,000 gpd reverse osmosis seawater system

The paper will review the design and operation of the 800,000 gpd reverse osmosis seawater system installed at the Punta Moron Station, of the C.A. de Administration y Fomento Electrico (CADAFE) of Venezuela. The plant will produce potable and boiler feed water for the utility. The specific areas discussed will be as follows: Pretreatment The design and operation of the Permutit Seawater Pretreatment system producing an influent to the membrane system with an SDI less than 3, will be described. Membrane System The B-10 Seawater Membrane system will be reviewed as to design and operation, with particular emphasis on the process and control features necessary to provide low maintenance operation. Brackish Water System p]The secondary brackish water B-9 system treating the influent from the seawater unit will be reviewed as to design and operation with particular emphasis on its ability to produce low TDS water for the demineralizers providing boiler feed water for the utility. The paper will outline data and the general experience with the operation of a large Reverse Osmosis Seawater plant. In addition, the integration of the brackish and seawater units into a single system will be reviewed. Operating costs will be outlined and the general question of Reverse Osmosis Seawater plant operation will be discuessed. The impact of the successful operation of this first single pass Reverse Osmosis Seawater System on the future of desalting technology will be evaluated.

Management of a closed brackish water system for high-density fish culture by biological and chemical water treatment

During a 1-year operation of a warm water recycling system (salinity about 8‰) sufficient water quality was maintained under high stocking density conditions using Tilapia and the European eel as potential candidates for intensive farming. The final fish: water ratio was 1 : 23 (or 43.5 g fish per 1 water) for the whole experimental culture unit. The total water volume of the system was about 5 m 3. The water treatment unit held 52% of the total volume, whereby 46% was available for fish culture. Combined biological (trickling filter with Hydropack-foil) and chemical (ozonation) water treatment proved to be useful to meet water quality requirements under these rearing conditions. After an initial conditioning period of the biofilter, BOD varied from 4.5 to 6.0 mg O 2/l, ammonium levels were maintained at less than 1 mg/l and nitrite concentrations averaged 1 mg/l. The average efficiency (oxidation rate) of the biofilter for NH 4 +-and NO 2 −-oxidation was 31% and 13.2%, respectively. The pH was stabilized slightly above 7.0 when a denitrification unit was connected to the system. Nitrate concentration of the system levelled of between 200 and 400 mg/l and was regulated by the addition of an electron donator (first glucose solution, then methanol) to the denitrification unit; the elimination rate averaged 50% with a maximum of 98%. High nitrite levels were avoided by ozone treatment of the recycled water. The accumulation of low-biodegradable substances was also successfully counteracted by ozonation. Fish growth rates of about 30% per month at high stocking densiteis were reached for Tilapia at a fish: water ratio of 1 : 4.6 (217 g fish per 1 water), indicating that a combination of biological water treatment and ozonation supports intensive fish culture in a closed aquaculture system.

Water weeds in Southern Africa

In Southern Africa, introduced water weeds have become serious pest plants in fresh and even brackish water systems only within the past twenty years, although in one case (water hyacinth) a warning of what was likely to happen was printed as early as 1913. The four main species involved are: Eichhornia crassipes (Mart.) Solms-Laubach, Myriophyllum aquaticum (Vell.) Verdcourt, Salvinia molesta Mitchell and Azolla filiculoides Lam. Between their introduction and the present, these plants, with the exception of Azolla, have spread widely over the whole region in suitable habitats and now pose threats to all the main river systems, hydro-electric and other water impoundments. No indigenous plants in these four genera are so far considered dangerous weed species, though some may have an occasional nuisance value.

MACROSCOPIC ALGAE OF THE COASTAL PONDS OF RHODE ISLAND

THE STENOHALINE marine and freshwater algae in eastern North America are fairly well known, but relatively little attention has been directed to the euryhaline flora which exists in the coastal brackish-water systems. Aside from Johnson and York's (1915) detailed investigations of Great Bay, Long Island, which were directed primarily toward factors affecting intertidal zonation, the student must rely upon information contained in general treatises (e.g., Taylor, 1937; Smith, 1950) for occasional notes relative to brackish water algae upon which the present work, though preliminary, is designed to focus attention.