Sediment and interstitial water chemistry of the Orbeteflo lagoon (Grosseto,Italy); nutrient diffusion across the water-sediment interface

The Orbetello lagoon is now highly eutrophic and has experienced increasing incidence of anoxia causing serious economic damage. A multidisciplinary study was commenced in March 1987 to investigate the part played by the lagoon sediments and interstitial water in recycling nutrients and contributing to the observed anoxia. Eleven undisturbed cores were collected and sub-sampled at 2 cm intervals. Interstitial water was obtained by centrifugation and analyzed for pH, Eh, nutrients, major and some minor elements. Differential fluxes from the sediments of 0.2–10 g cm^–2 day^–1 of ammonia and 0.02–0.7 g cm^–2 day^–1 of orthophosphate were obtained depending on the season, temperature of the sediments and the sampling location. A highly significant linear correlation (r ² = 0.86) was found between bicarbonate and ammonia concentrations in the interstitial waters, due to the release of these compounds during the degradation organic matter. A diagenetic model was developed to predict the alkalinity of interstitial water from the theoretical reactions involved in the decomposition of organic matter. The predicted values for bicarbonate and ammonia agreed well with the experimental results.     

Relation between phosphate and organic matter in fish-pond sediments of the Deroua fish farm (Béni-Mellal, Morocco): implications for pond management

An experimental approach of the phosphate exchange across the water–sediment interface in fish ponds of the Deroua farm (Béni-Mellal, Morocco) is needed to understand the phosphate dynamics in these ponds in relation to their water quality. During this study, we conducted experiments to determine the P-fractions of the different pond sediments and to estimate the release from these sediments of phosphate available for algal uptake. We also determined the amount of phosphate needed to saturate the sediments of two different fish ponds under anoxic and oxic conditions. Phosphate release from sediments comes mainly from Fe(OOH)P and is more important in ponds lined with sheets. The accumulation of organic matter in sediments favours the installation of anoxic conditions and enhances the phosphate release from CaCO₃P, labile in these pond sediments. Under experimental conditions, org-P plays a minor role in the P-release. Oxic conditions, to the contrary, have an inhibitory effect on the P-release from sediments. About 80–98% of the P-adsorbed onto different pond sediments was recovered in the inorg-P-fractions. Aeration induces the oxidation of FeS to Fe(OOH) which can adsorb phosphate from solution. Besides, the presence of bacteria in pond sediments was essential to promote phosphate release under anoxic conditions by controlling the oxidation state of iron and the mineralization of the organic matter. Sheet-lined ponds, when insufficiently dried, accumulate a large quantity of organic matter in their sediments. After a decrease in pH, P is released from CaCO₃P and enhances the phytoplankton productivity responsible for renewed accumulation of organic matter. Org-C concentrations in sediments over 20 mg g^–1 d.w. favour the formation of toxic factors (Fe²⁺, Mn²⁺, NO₂ ^– and H₂S) harmful for carp growth. An extended period of drying efficiently enhances the mineralization of organic matter.     

Evaluation of different bioremediation protocols to enhance decomposition of organic polymers in harbour sediments

The response of the microbial community (in term of abundance and enzymatic activity) was investigated to test the effect of different bioremediation protocols to naturally enhance decomposition of organic polymers in harbour sediments (Genoa Harbour, Italy, N–W Mediterranean). Bioremediation techniques tested were bioaugmentation (5 different microorganisms inocula), biostimulation (air supply), and natural attenuation. The coupling bioaugmentation/biostimulation was also tested. After 60days, following the bioaugmentation protocol, bacterial densities correlated to the quantities of inocula amended to the boxes, suggesting that allochthonous community was able to survive and multiply. However, while bioaugmentation alone seems not to be able to carry out significative degradation, its coupling with air insufflations produced the best response: here bacterial densities increased, especially in the water (from 2.3×10⁷ to 3.50×10⁸cells ml^–1), average cell size and enzymatic activities increased, and sedimentary organic matter was significantly depleted (PRT 5-folds reduction, CHO 1.5-folds reduction). The strong coupling observed between the sediment and water compartments together with the greatest microbial response observed in this latter suggest that the sediment–water interface may constitute a key compartment for the occurring of biodegradation processes in organic-rich sediments.     

Lipid composition of water and surface sediments in Takapoto atoll lagoon (French Polynesia)

Dissolved, particulate and sedimentary lipid compounds were analyzed in samples collected in May 1988 at three sites in the lagoon of the closed atoll of Takapoto (Tuamotu archipelago, French Polynesia). The study provides background information dealing with water quality and the nature and concentration of lipids. Non-aromatic hydrocarbons and fatty acids were isolated from lipids and analyzed by gas chromatography/mass spectrometry. Non-aromatic hydrocarbon concentrations did not exceed 1000 ng l^-1 in water, and 2300 ng g^-1 in surface sediments and are among the lowest encountered in pristine marine environments. No noticeable petroleum pollution was evidenced in the lagoon. Nevertheless, traces of petroleum-derived compounds were detected at the central site for both surface and deep water. Total fatty acid concentrations varied in the range 6.3–14.4 g l^-1 for the particulate phase and in the range 0.5–3.2 g l^-1 for the dissolved phase. The molecular fingerprints of fatty acids and hydrocarbons evidenced a predominant algal, and to a lesser extent microbial, origin of the organic matter present in water and sediments. Mono- and polyunsaturated fatty acids, which are essential components for animal metabolism, were identified in noticeable amounts in suspended matter (1.8–4.6 g l^-1), and at highly variable levels in the dissolved phase (0.08–1.21 g l^-1).     

Late winter microbial communities in the western Weddell Sea (Antarctica)

Microbial communities in the water column and sea ice were studied during the EPOS-cruise on R/V Polarstern in the western Weddell Sea in late winter (October–November 1988). Samples were taken from four transects from heavy pack-ice to open water. The results indicated the important role of protozoans especially in the ice-edge area. Heterotrophic nanofiagellates, dinoflagellates, ciliates and sarcodines showed significant positive correlations with chlorophyll a. Autotrophic picoplankton and autotrophic flagellates, which were probably motile zooids of Phaeocystis pouchetii (up to 3×10⁶ cells 1^–1), were most abundant in the areas of low or medium chlorophyll a concentration. Sea ice contained high numbers of heterotrophic organisms, and the distribution of the different groups showed distinct vertical zonation. At two sites, the microbial assembly beneath the ice was clearly influenced by communities from the melting ice.Data presented here were collected during the European Polarstern Study (EPOS) sponsored by the European Science Foundation     

Seasonal denitrification in flooded and exposed sediments from the Amazon floodplain at Lago Camaleão

Denitrification processes were measured by the acetylene-blockage technique under changing flood conditions along the aquatic/terrestrial transition zone on the Amazon floodplain at Lago Camaleão, near Manaus, Brazil. In flooded sediments, denitrification was recorded after the amendment with NO ₃ ^– (100 mol liter^–1) throughout the whole study period from August 1992 to February 1993. It ranged from 192.3 to 640.7 mol N m^–2 h^–1 in the 0- to 5-cm sediment layer. Without substrate amendment, denitrification was detected only during low water in November and December 1992, when it occurred at a rate of up to 12.2 mol N m^–2 h^–1 Higher rates of denitrification at an average rate of 73.3 mol N m^–2 h^–1 were measured in sediments from the shallow lake basin that were exposed to air at low water. N₂O evolution was never detected in flooded sediments, but in exposed sediments, it was detected at an average rate of 28.3 mol N m^–2 h^–1 during the low-water period. The results indicate that under natural conditions there is denitrification and hence a loss in nitrogen from the Amazon floodplain to the atmosphere. Rates of denitrification in flooded sediments were one to two orders of magnitude smaller than in temperate regions. However, the nitrogen removal of exposed sediments exceeded that of undisturbed wetland soils of temperate regions, indicating a considerable impact of the flood pulse on the gaseous turnover of nitrogen in the Amazon floodplain.     

Denitrification in a seashore sandy deposit influenced by groundwater discharge

The chemical compositions of ground water and organic matter in sediments were investigated at a sandy shore of Tokyo Bay, Japan to determine the fate of ground water NO₃ ^–. On the basis of Cl^– distribution in ground water, the beach was classified into freshwater (FR)-, transition (TR)-, and seawater (SW)-zones from the land toward the shoreline. The NO₃ ^– and N₂O did not behave conservatively with respect to Cl^– during subsurface mixing of freshwater and seawater, suggesting NO₃ ^– consumption and N₂O production in the TR-zone. Absence of beach vegetation indicated that NO₃ ^– assimilation by higher plants was not as important as NO₃ ^– sink. Low NH₄ ⁺ concentrations in ground water revealed little reduction of NO₃ ^– to NH₄ ⁺. These facts implied that microbial denitrification and assimilation were the likely sinks for ground water NO₃ ^–. The potential activity and number of denitrifiers in water-saturated sediment were highest in the low-chlorinity part of the TR-zone. The location of the highest potential denitrification activity (DN-zone) overlapped with that of the highest NO₃ ^– concentration. The C/N ratio and carbon isotope ratio (¹³C) of organic matter in sediment (< 100 -m) varied from 12.0 to 22.5 and from –22.5 to –25.5, respectively. The ¹³C value was inversely related to the C/N ratio (r ² = 0.968, n = 11), which was explained by the mixing of organic matters of terrestrial and marine origins. In the DN-zone, the fine sediments were rich in organic matters with high C/N ratios and low ¹³C values, implying that dissolved organic matters of terrestrial origin might have been immobilized under slightly saline conditions. A concurrent supply of NO₃ ^– and organic matter to the TR-zone by ground water discharge probably generates favorable conditions for denitrifiers. Ground water NO₃ ^– discharged to the beach is thus partially denitrified and fixed as microbial biomass before it enters the sea. Further studies are necessary to determine the relative contribution of these processes for NO₃ ^– removal.     

Synthesis of organic compounds from carbon monoxide and water by UV photolysis

The photolysis of water vapor with carbon monoxide at 1849 Å yields alcohols, aldehydes and organic acids, with an overall quantum yield of 3.3×10^–2. This rather high quantum yield could have led to a contribution of 10¹¹ organic molecules cm^–2 sec^–1 to the pool of organic material on the primitive Earth. The reactions are initiated by the photolysis of water molecules and the resulting hydrogen atoms reduce the carbon monoxide to a variety of one and two carbon compounds. The organic molecules are dissolved in water and thus escape destruction by photolysis. Photolysis of water vapor with carbon dioxide did not yield organic compounds under these conditions.     

The role of plankton, zoobenthos, and sediment in organic matter degradation in oligotrophic and eutrophic mountain lakes

Intensity of organic matter degradation, assessed by the respiratory electron transport system (ETS) activity, was studied in microplankton, zooplankton, chironomid larvae as the dominant group of the macrobenthos, and sediment in mountain lakes of different trophic levels in summer months. The highest ETS activities per unit of surface were observed in sediments. Significantly lower activities were observed in microplankton, and lower still in zooplankton, and chironomids. The total ETS activity m^–2 was higher in eutrophic lakes (Jezero na Planini pri Jezeru and Krnsko jezero) than in oligotrophic ones (Zgornje Kriko jezero, Spodnje Kriko jezero, Jezero v Ledvicah). The contributions of communities investigated to total ETS activity m^–2 differed between lakes of different trophic level. Estimation of respiratory carbon loss through different components revealed that the most of the organic matter was oxidized in sediments of mountain lakes. The respiratory carbon losses were higher through zooplankton than through microplankton in all lakes. Carbon losses through plankton components and sediments were significantly lower in oligotrophic than in eutrophic lakes. The contribution of respiratory carbon loss through chironomids to total carbon loss m^–2 was higher in oligotrophic than in eutrophic lakes. Therefore, it seems that contributions of microplankton and zooplankton to mineralization processes increase, and contributions of chironomids and sediment surface decrease with increasing trophic level of the lakes.     

Phytoplankton distribution in relation to sea ice,hydrography and nutrients in the northwestern Weddell Sea in early spring 1988 during EPOS

Summary Phytoplankton biomass and distribution of major phytoplankton groups were investigated in relation to sea ice conditions, hydrography and nutrients along three north-south transects in the north western Weddell Sea in early spring 1988 during the EPOS Study (European Polarstern Study), Leg 1. Three different zones along the transects could be distinguished: 1) the Open Water Zone (OWZ) from 58° to 60°S with high chlorophyll a concentrations up to 3.5 g l^–1; 2) the Marginal Ice Zone (MIZ) from 60° to about 62.5° with chlorophyll a concentrations between 0.1 and 0.3 g l^–1, and 3) the closed pack-ice zone (CPI) from 62.5° to 63.2°S with chlorophyll a concentrations below 0.1 gl^–1. Nutrient concentrations increased towards the south showing winter values under the closed pack-ice. Centric diatoms such as Thalassiosira gravida and Chaetoceros neglectum forming large colonies dominated the phytoplankton assemblage in terms of biomass in open water together with large, long chain forming, pennate diatoms, whereas small pennate diatoms such as Nitzschia spp., and nanoflagellates prevailed in ice covered areas. Fairly low concentrations of phytoplankton cells were encountered at the southernmost stations and many empty diatom frustules were found in the samples. The enhanced phytoplankton biomass in the Weddell-Scotia-Confluence area is achieved through sea ice melting in the frontal zone of two different water masses, the Weddell and the Scotia Sea surface waters.Data presented here were collected during the European Polarstern Study (EPOS) sponsored by the European Science Foundation     

Spatial distributions of copepod genera along the Atlantic Meridional Transect

The distribution of copepod taxa at a basin scale was analysed using three Atlantic transects (U.K. – Malvinas 1997, Malvinas – U.K. 1997, and South Africa – U.K. 1998). Integrated 200 m to surface zooplankton samples were taken daily, using WP2 nets (200-m mesh). The zooplankton were size-fractionated and sub-samples taken for carbon analysis. The remainder of the samples was preserved for taxonomic analysis of copepod genera. Multidimensional scaling (MDS) was used to identify zoogeographic regions from the copepod genera. Seven regions were identified: northern temperate, northern subtropical, equatorial, southern tropical, southern sub-tropical, southern temperate and Benguela upwelling. Analysis of similarity showed that most regions were significantly different from each other except: northern temperate and southern temperate, northern temperate and southern subtropical, and northern subtropical and southern subtropical. The genera significant in determining the regions were identified. These regions were compared to other schemes of biological and hydrographic areas. The MDS also showed that the copepod composition in the tropical and subtropical regions was less variable than the temperate and Benguela stations. Latitudinal trends in diversity and size were also investigated. Copepod genera showed a reduction in richness at higher latitudes. Copepod size did not show any substantial or consistent change with latitude along these transects, as demonstrated by both the numerical abundances in each size category, and the carbon biomass per individual. The proportion in each size fraction was quite uniform over the transect.     

Microbial cycling of iron and sulfur in sediments of acidic and pH-neutral mining lakes in Lusatia (Brandenburg, Germany)

A vast number of lakes developed in the abandoned opencast lignite mines of Lusatia (East Germany) contain acidic waters (mmolSm^–2a^–). Potential Fe(III) reduction measured by the accumulation of Fe(II) during anoxic incubation yielded similar rates in both types of sediments, however, the responses towards the supplementation of Fe(III) and organic carbon were different. Sulfate reduction rates estimated with ³⁵S-radiotracer were much lower in the slightly acidic sediment than in the pH-neutral sediment (156 v.s. 738mmolSO₄ ^2–m^–2a^–1). However, sulfate reduction rates were increased by the addition of organic carbon. Severe limitation of sulfate-reducing bacteria under acidic conditions was also reflected by low most probable numbers (MPN). High MPN of acidophilic iron- and sulfur-oxidizing bacteria in acidic sediments indicated a high reoxidation potential. The results show that potentials for reductive processes are present in acidic sediments and that these are determined mainly by the availability of oxidants and organic matter.     

Primary organic production in the Atlantic Ocean

Summary The determination of 24-h primary organic production of phytoplankton photosynthesis under 1 m² in the vast areas of open parts of the Atlantic ocean was made by using isopic technique. It was stated that the production is maximal in coastal waters of Europe (0,8–1,3 g C/m²) and especially of the west coast of Africa (to 3,4 g C/m²). Middle rate of production was observed in the North Atlantic Current, and the Equatorial Current (0,2–0,6 g C/m²). Relatively low organic production was found in the tropical waters of the Equatorial Current (about 0,1 g C/m²). Production in the transparent waters of the Sargasso sea was very low (0,03–0,05 g C/m²). Upper data corresponds well with that which had been collected by the Galathea expedition in the same regions of the Ocean. Definite correlation between the rate of primary production and standing crop of crustacean zooplankton was observed in tropical waters.     

Inorganic phosphate in exposed sediments of the River Garonne

Fractionation of inorganic phosphates in sediments of the River Garonne was carried out during a period of low water discharge. Sediments were collected under 5 cm of water (LS), in the dried river bank (MS) and in the riparian forest (RS). Sediments were sampled at two dates, during a period in which the water level fell gradually, causing sediment LS to be air exposed.Sediments were analysed for total phosphate, iron bound phosphate (Fe(OOH)P) using Ca-NTA and Ca bound phosphate (CaCO₃P) using Na-EDTA.Total-P varies from 552 (RS at date 1) to 2072 µg g^–1 (LS at date 2). There are significant differences between sediments and a significant increase from date 1 to date 2 in sediment LS only (1825 to 2072 µg g^–1). Fe(OOH)P varies from 186 (RS at date 1) to 874 µg g^–1 (LS at date 2). The highest values correspond to sediment LS. Moreover, Fe(OOH)P increased significantly between date 1 and 2 in LS (560 to 874 µg g^–1) as well as in sediment MS (248 to 432 µg g^–1). Ca bound P concentrations differed significantly between sediments (75, 112, 235 µg g^–1 for sediments RS, MS and LS respectively) but not between sampling dates.These differences are attributed to the conditions of deposition of the sediments (such as morphology and hydrology of the river) and to the changes in chemical composition during the drying out of the sediments.     

The use of stable carbon isotopes as tracers of ecosystem functioning in contrasting wetland ecosystems of Lake Victoria,Kenya

Aquatic macrophytes and sediments from two contrasting wetland ecosystems of Lake Victoria, Kenya (Lower Sondu Miriu and Kibos systems) were analyzed for their stable carbon isotopic composition in order to observe patterns in system functioning in these two ecosystems. The aquatic macrophytes had carbon isotope ratios ranging from –8.92 to –29.18 per mil (parts per thousand difference from the reference). For the dominant macrophytes, we observed most ¹³C enriched values for Cyperus papyrus and most ¹³C depleted values for Eichhornia crassipes. On transects from the river to the lake, Kibos sediments maintained lower carbon isotope signatures compared to the Lower Sondu Miriu sediments. The possible causes of the observed variation in the ¹³C signatures from sediments and aquatic macrophytes in the two-wetland ecosystems are outlined.     

Sulfate reduction processes in sediments at different sites in Lake Kinneret,Israel

Lake Kinneret, Israel, is a warm (13–30°C) monomictic lake that stratifies in April and turns over in December. Between January and June each year, a heavy bloom (up to 250 g wet weight n^–2 2) of the dinoflagellate Peridinium gatunense dominates the phytoplankton biomass. In early summer, the bloom collapses, and the sinking Peridinium biomass serves as a trigger for intense sulfate-reduction activity throughout the hypolimnion and within the sediments. The availability of organic matter and sulfate was high shortly after the bloom crash and the beginning of stratification and was lowest in December before overturn. Sulfate-reduction rates at three different sites in the lake were studied. In the sediments, the rates varied seasonally and among stations from 5 to 1600 nmol SO₄ ^–2 reduced cm^–3 day^–1, with respect to the distance from the Jordan River, depth, organic content, and stratification period. During years of low lake water levels, intense sulfate reduction occurred in the hypolimnion, resulting in anoxia and high concentrations of H₂S (>400 m). In years with high water levels, early bloom, and delayed stratification, higher rates of sulfate reduction were recorded in the sediments, probably as a result of a greater fraction of the primary production (organic matter) reaching the bottom. Correspondence to: O. Hadas.     

Bacterial Processes of the Methane Cycle in Bottom Sediments of Lake Baikal

The activity of methanogenic and methanotrophic bacteria was evaluated in bottom sediments of Lake Baikal. Methane concentration in Baikal bottom sediments varied from 0.0053 to 81.7 ml/dm³. Bacterial methane was produced at rates of 0.0004–534.7 l CH₄/(dm³ day) and oxidized at rates of 0.005–1180 l CH₄/(dm³ day). Peak methane production and oxidation were observed in Frolikha Bay near a methane vent. Methane was emitted into water at rates of 49.2–4340 l CH₄/(m² day). Rates of bacterial methane oxidation in near-bottom water layers ranged from 0.002 to 1.78 l/(l day). Methanogens and methanotrophs were found to play an important role in the carbon cycle through all layers of sediments, particularly in the areas of methane vent and gas-hydrate occurrence.     

Is bacterioplankton production in the Ria de Aveiro influenced by salt marshes and bed sediment?

The contribution of potential export of materials from bottom sedimentsand salt marshes into the water column of a shallow estuarine system of Ria deAveiro to the observed high bacterial productivity in the mid section of thisestuary was evaluated. Vertical profiles of physical, chemical and bacterialvariables were studied in the marine and brackish water zones, and oftransversal profiles in the brackish zone only. Although the concentrations ofseston (17–241 mg l^–1), particulate organiccarbon (3–15.5 mg l^–1) and chlorophyll(1.2–7.0 g l^–1) varied widely, thevertical and transversal profiles were without much variation. Total bacterialnumber (0.2–8.5 × 10⁹ cellsl^–1) and the number of particle-attached bacteria(0.02–2.50 × 10⁹ cellsl^–1)along vertical and transversal profiles did not differ much, but the rate ofbacterial production (0.05–14.2 g C l^–1h^–1) and dissolved organic carbon concentration(6.0–69.2 mg l^–1) were frequently highernear the salt marsh margin at the brackish water transect. The increase inproductivity could not be associated with runoff of particulate matter butcoincided with the inputs of dissolved organic carbon. The results of verticaland transversal profiles point to a minor role of particulate matter additionsfrom the salt marsh area or from bed sediments.     

Observations on some common parasites of Bagrus docmac Forskahl (pisces: siluroidea) of lake Victoria

During the June–August period, 1977, four sets of water and sediment samples were collected for bacteriological analysis, from a salt-fresh water shoreline transect in Northern Canada (51°30 north latitude). Samples were processed for health indicator bacteria, organic sulfur reducing bacteria, ammonifying bacteria, denitrifying bacteria and ATP. Some chemical parameters were also studied. Based on the water classification scheme proposed by Sorokin & Kadota, the total bacterial population found in the sea sampling stations, would indicate that these waters are very eutrophic. The microbial biomass in these waters leads one to suspect that there may be an underestimation of the potential biodegradation capacity of these waters.     

Beiträge zur Entsalzung mit Retardion 11A8

Zusammenfassung 1. Das Arbeiten mit dem Ionenverzögerungsverfahren wird eingehend beschrieben.2. Die optimalen Bedingungen für die Trennung organischer Testsubstanzen von anorganischen Salzen bei Raumtemperatur sind: zwei hintereinandergeschaltete Säulen mit einem Gesamtvolumen von 225 ml Retardion 11A8; 50 bis 100 ml Analysenprobe einer 3,5prozentigen oder 50 ml einer 7prozentigen Salzlösung; 60 ml/h Durchflußgeschwindigkeit; 4 bis 5 1 Wasser zum Eluieren und Regenerieren der Säulen.3. Aus der organischen Fraktion werden an zugesetzten Ionen entfernt: Cl^– 96,2%; So₄ ^–– 63,4%; Mg⁺⁺ 97,7%; Ca⁺⁺ 96,8%.4. Es werden Maßnahmen zur Wiederherstellung von gestörtem Gleichgewicht der Säulen beschrieben.5. Mit Retardion 11A8 läßt sich ein Salzgemisch in seine einzelnen Komponenten zerlegen. Die Reihenfolge der untersuchten Ionen im Säuleneluat ist: PO₄ ^–––, CO₃ ^–– und HCO₃ ^–, SO₄ ^––, Cl^–, Br^–; NH₄ ⁺, K⁺, Na⁺, Mg⁺⁺, Ca⁺⁺. Die Abtrennung der Erdalkali ist besonders scharf.6. Die Elutionskurven von vielen Aminosäuren und verwandten Verbindungen, Kohlenhydraten, anorganischen und organischen Phosphatverbindungen, organischen Säuren, Harnstoff und Gelbstoff werden beschrieben.7. Der Prozentsatz des Wiederauffindens zugesetzter organischer Testsubstanzen, die von Salzen getrennt werden, beträgt 95 bis 100 für die meisten Aminosäuren, Kreatin, Zucker, Zuckeralkohole und für einige Phosphorsäureester. Die Ausbeute von Asparaginsäure und basischen Aminosäuren, Histamin, Glucosamin, Glucosediphosphat und organischen Säuren ist geringer.8. Die Vor- und Nachteile sowie einige Möglichkeiten der Anwendung des Ionenverzögerungsverfahrens mit Retardion 11A8 in der Hydrobiologie, Biochemie und Meeresbiologie werden diskutiert.

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Contributions to desalting with Retardion 11A8

The isolation and determination of the soluble organic substances in sea water is very difficult because of the presence of large amounts of inorganic salts. In order to desalt the water, ion retardation with Retardion 11A8 seems to be a very efficient method. Since this procedure is at the present almost unknown, the optimal conditions of separation which have been found are described in this paper. The selectivity of the resin for different ions occurring in sea water is studied. The elution curves of a large number of organic substances (amino acids, carbohydrates, organic phosphorus compounds and organic acids) are described. Recovery of given concentrations of these substances, added to 50 ml of a salt solution similar to sea water, is 95 to 100% for most of the amino acids, carbohydrates and organic phosphorus compounds but less for other substances. Using ion retardation as a desalting means, more than 90% of the inorganic salts may be removed from the organic fraction by a one-step procedure. These experiments may be done on a larger scale in desalting larger volumes of sea water. Ion retardation has proved to be an excellent separation method for biochemistry and water chemistry. Work is in progress to use Retardion 11A8 as a desalting means in the isolation of organic matter from sea water.

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Herrn Professor Dr.Adolf Bückmann zum 65. Geburtstag in Verehrung gewidmet.

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Der Deutschen Forschungsgemeinschaft danke ich für die Unterstützung der Arbeit.