G. Kattner

Simple gas-liquid chromatographic method for the simultaneous determination of fatty acids and alcohols in wax esters of marine organisms

A rapid and simple gas-liquid chromatographic analysis of fatty acids and alcohols of lipid extracts is described. Calanoid copepods were chosen because they contain large amounts of was exters. Lipid extracts were analysed directly after trans-esterification and subsequent hexane extraction. In a single chromatogram fatty acid methyl esters and fatty alcohols were analysed simultaneously on capillary columns coated with SILAR 10 c and CP SIL 5 CB. The major and most of the minor compounds can be determined. Time-consuming separation and purification steps, e.g. by thin-layer chromatography, which can cause loss of polyunsaturated fatty acids and alcohols, are thus avoided.

Development of lipids during a spring plankton bloom in the northern North Sea: I. Particulate fatty acids

Abstract The plankton spring bloom in the northern North Sea was extensively investigated during a period of three months in 1976 at a fixed station occupied by the R.V. “Meteor”. Samples of different depth-profiles, representative of the phytoplankton development, were collected eleven times to analyze the concentration of fatty acids of the particulate matter. The water column was divided into an upper and lower layer according to the thermocline depths, because different processes take place in these layers. During the exponential growth phase the fatty acid concentration rose only slightly due to increases in polyunsaturated fatty acids (18:4, 20:5, 22:6), which are typical for marine plankton. With the exhaustion of nutrients the biochemical composition changed and the fatty acid concentration increased sharply from about 3 to 20 μmol C dm − finally to about 30% of the particulate carbon. The main proportion consisted of oleic acid (28.3%) and palmitic acid (24.2%). The first phytoplankton bloom, dominated by diatoms (Chaetoceros species), was characterized by the increase in fatty acids with 16 carbon atoms, whereas during the second smaller bloom, with dinoflagellates as the main species, more fatty acids with 18 carbon atoms occurred. After the stationary growth phase the phytoplankton biomass strongly decreased, resulting in an increase of particulate matter below the thermocline. The fatty acid pattern there was similar to that during the stationary phase of the phytoplankton bloom in the upper layer.

Automatic method for the determination of ortho-phosphate and total dissolved phosphorus in the marine environment

ZusammenfassungFür die Bestimmung von ortho-Phosphat in Seewasser wird eine automatische Methode beschrieben, die auf der üblichen Molybdänblaumethode basiert und sehr empfindlich ist, weil die Proben mit einer sehr geringen Menge Reagenz verdünnt werden. Für die Reaktionseinheit wird ein Allglassystem vorgeschlagen, der Einsatz von Plastikmaterial sollte weitgehend vermieden werden. Die beschriebene Methode ist in leicht modifizierter Form auch für die Bestimmung von gelöstem Gesamt-Phosphor geeignet, wenn die Proben zuvor mit Peroxodisulfat aufgeschlossen werden. Die Methode liefert bei einer Probenfrequenz von 30 h−1 für ortho-Phosphat und gelösten Gesamt-Phosphor genaue Ergebnisse im Bereich von 0,01–5 μg at P/1.SummaryAn automatic method for the determination of ortho-phosphate in seawater is described. It is based on the original molybdenum blue method and is very sensitive because of the very small dilution of samples by reagents. An all-glass reaction manifold is proposed, the use of plastic material should be avoided as far as possible. The described method may also be used in a slightly modified version for the determination of total dissolved phosphorus, when samples are first digested with peroxidisulfate. Orthophosphate and total dissolved phosphorus can be determined exactly in the concentration range from 0.01–5 μg at P/l with a sampling frequency of 30 h−1.

Fatty-acid composition of dissolved and particulate matter in surface films

Lipids containing fatty acids, together with other surface-active substances, can form continuous films on the sea surface. Owing to the complex structures of fatty acids, they are suitable for use as tracers in investigations of the origin and fate of surface films. Surface films were sampled west of the island of Sylt from the 20th to 22nd of August, 1974. After filtration, the fatty-acid composition of the chloroform-soluble part was analyzed in the particulate and dissolved fractions, respectively. Thereby different types of surface films could be characterized, which varied in total quantity, as well as in the relative amounts of fatty acids in the filtrate and particulate matter. It is plausible that such fatty acids will accumulate at surfaces which are chemically stable, as e.g. the saturated fatty acids, which are more resistant to photolytic and chemical degradation than their unsaturated counterparts. The fatty-acid patterns changed as soon as the film contained a large amount of particulate lipids, which shows correlations to the dissolved surface-active substances. Thus, correlations between the fatty-acid pattern in the surface film and that of Prorocentrum micans could be determined.

Development of lipids during a spring plankton bloom in the northern North Sea: II. Dissolved lipids and fatty acids

Abstract During the spring plankton bloom (1976) in the northern North Sea the fatty acid and lipid distribution of the chloroform extractable fraction of seawater was analyzed by gas chromatography and thin-layer chromatography. The fatty acids in the seawater made up about 3% of the total dissolved organic matter. Maximum concentrations during the first phytoplankton bloom were in the range of 5 μmol C dm−3. Palmitic acid (30.4%) and oleic acid (21.4%) as well as myristic, stearic and palmitoleic acids were the main fatty acids. The concentrations of fatty acids were higher below the thermocline in the deeper layers of the water column. The oleic acid showed large fluctuations, especially below the thermocline and seemed to be bound in a polar fraction. Different lipid classes containing fatty acids were determined by thin-layer chromatography. An estimation showed that the free fatty acid fraction made up the main portion (47.9%), followed by the triacylglycerol fraction (22.8%) and a more polar fraction with 25.1%. The triacylglycerol fraction appears to be more stable than the other fraction in the water column.

Natürliche Oberflächenfilme im Seegebiet vor Sylt

The physical and chemical properties of the sea surface can be altered considerably by the formation of slicks and the accumulation of particles (including plankton). Investigations of natural slicks near the island of Sylt consisted of analyses of the dissolved and particulate surface-active substances, as well as the identification of plankton and bacteria collected by a surface-film sampler. The analyzed surface material consisted primarily of phytoplankton (Prorocentrum micans in particular), bacteria, detritus and dissolved compounds of fatty acids. These fatty acid compounds alone would not account for the slick. The slick appeared to be caused by the calm weather, the active accumulation of P. micans at the surface, and the increase in bacteria associated with this accumulation. Here a decrease was observed in the dissolved surface-active substances compared with the concentration usually found in normal surface waters, of which the total fatty acid content in a sample was taken as indicator. In some cases a correlation was found between fatty acids and particulate matter in naturally occurring slicks. Particularly large variations were found in the fatty acid patterns in the filtrate and filter residue at a time when no slick was present and no particulate matter had accumulated at the surface.

Release of Dissolved Organic Substances in the Course of Phytoplankton Blooms

Organic matter in the sea represents a continuous size spectrum, beginning with free, small molecules, macromolecules, colloids and aggregates and ending with planktonic organisms. By arbitrary definition, the fraction passing filters with pore sizes of 0.5 to 1.0 μm is defined as the dissolved fraction (Williams 1975). This fraction constitutes by far the major part of organic matter (DOM) in the sea (Mopper and Degens 1979, Cauwet 1981), more than 60% of which is still unidentified.

Semi-automated methods for the determination of particulate phosphorus in the marine environment

ZusammenfassungDer Rückstand bei Filtration von Meerwasser durch Glasfaserfilter wird mit Schwefelsäure und Wasserstoffperoxid aufgeschlossen. Die anschließende Phosphatbestimmung basiert auf der Bildung eines Phosphormolybdän-Komplexes. Sie wurde modifiziert, so daß der Phosphor-Gehalt der Proben sofort nach Aufschluß mit dem Durchflußsystem des Technicon-AutoAnalyzers bestimmt werden kann. Zwei Methoden mit unterschiedlicher Empfindlichkeit (von 0,1–10μmol P · l−1) werden beschrieben.SummaryAfter filtration of sea water through glass fiber filters, the filters with the residue are digested by heating with sulphuric acid and hydrogen peroxide. The following determination of phosphate is based on the formation of a phosphomolybdenum complex. It has been modified in such a way that the phosphorus content of the samples can be determined with a continuous-flow system with the TechniconAutoAnalyzer direct after digestion. Two methods are described for different sensitivities of 0.1–10μmol P · l−1.

Fluctuations of Dissolved Amino Acids: A Comparison of Natural and Enclosed Phytoplankton Populations in the North Sea

Cumulative production of dissolved organic material (DOM) from the classical food web containing phytoplankton excretion, losses during grazing, and Zooplankton excretion, was estimated to amount to about 60% of primary production (Williams 1981). A good part of this material is in a steady state of release and heterotrophic uptake by the various members of a plankton community. Because of the intricate interactions, little is known about the fate of these substances. Results from laboratory experiments are of limited use and sometimes misleading (Hellebust and Guillard 1967; Sharp 1977). On the other hand, investigations in the open sea are more complicated considering the hydrodynamic influences.

Composition of Natural Surface Films in the North Sea

The appearance of surface films, so-called “slicks”, is an often observed phenomenon. Besides the articial surface films, which are caused by man made pollutions, e.g. oil spills from ships or oil accidents, natural surface films can result from dissolved and particulate organic substances released by the organisms of this biotope. Due to the large amount of dissolved organic matter in sea water, natural surface films can be formed spontaneously on the sea surface, if wind velocity is below about 3 Bft. Waves and turbulences caused by stronger wind forces will mix surface and subsurface waters.