ALBERT

Description: research

Description: Voruntersuchungen zu dieser Arbeit befaßten sieb mit der stoffgruppen-chemischen Auftrennung der organischen Substanz in den organo-mineralischen A -Horizonten von benachbarten und typischen Rendsinen und Sauer-Braunerden unter Laub und Coniferen-Forsten der mitteldeutschen Berg- und RUgel-Landschaften. Die Untersuchungen ergaben: Bei gleichen Baumbeständen und in einer Distanz von nur wenigen Metern war der Gleichgewichts-Humusspiegel in den Ab-Horizonten (0 - 25 cm) der Rendsinen ca. 4-mal so hoch wre der mittlere Humus-Gehalt in den oberen 15 cm der Sauer-Braunerden. Die organische Substanz der eutrophen, kalkhaltigen Rendsinen bestand zu hohen Anteilen aus höher-polymeren Huminstoffen (Huminsäuren und lluminen), während bei den stark sauren Braunerden die Fraktionen der niedermolekularen Fulvosäuren und Streustoffe den Hauptanteil der organischen Komponente bildeten. Für die Sauer-Braunerden konnte anband der Verteilung von aggres- siven Fulvosäuren, organischen Säuren (z.B. Uronsäuren) und Kohlenhydraten nachgewiesen werden, daß die Humus- Zufuhr zum Mineralkörper des Bodens zu erheblichen Teilen durch Infiltration bewerkstelligt wird. Bei den Rendsinen erfolgt dagegen die Inkorporation durch intensive biolo- gisch-mechanische Beimischung. Während bei den Rendsinen der Umsatz der organischen Sub- stanz überwiegend im oberen Abschnitt des Solums abläuft und eine Auflage-Humus-Decke fehlt, spielt sich bei den Sauer-Braunerden der Umsatz hauptsächlich in der Humus- Auflage ab. Die Mengen und das Spektrum der organischen Substanzen, die infiltrativ in das mineralische Substrat gelangen und dort fixiert oder abgebaut werden, sind im Vergleich zu den Rendsinen gering. Sie scheinen durch eine selektiv abbau-wirksame biologische (Pilz-) Sperre in der Auflage-Decke oder an deren Untergrenze bestimmt zu werden. Als Fazit dieser Untersuchungen wurde empfohlen, zur Klä- rung der unterschiedlichen Humus-Metabolik mit Hilfe standorts-biologischer Methoden das Gewicht auf die Klärung folgender beiden Fragen zu legen:

Description: research

Description: research

Description: Die Fragestellung, die den hier mitgeteilten Untersuchungen zugrunde liegt, hat sich aus Forschungsarbeiten ergeben, die einem ganz anderen Problemkreis gewidmet waren: Es handelte sich dabei um die Frage nach den Entwicklungsprozessen und dem Entwicklungsstand der Bodenbildung im Alleröd, Es ist dies die bedeutendste der kurzen vorholozänen Bodenbildungs-Phasen, in der aus den spätglazialen Periglazial-Ablagerungen, dem im bodenkundliehen Sinne "frischen Ausgangs-Material", wie Löß, Frost-Wanderschutt, Flugsand etc., die ersten schwach entwickelten "Böden" hervorgingen. Die Kenntnis der allerödzeitlichen Bodenbildung ist insofern von Bedeutung, als die Böden in der auf das Alleröd folgenden jüngeren Tundrenzeit meist nur noch in geringem Maße zerstört wurden und als "präforma-tive Bodenentwicklungsphasen den Ablauf der später ein- setzenden holozänen Bodenentwicklung beeinflußt oder vorgezeichnet haben können. Als geeignetes Studienobjekt bieten sich die begrabenen Alleröd-Böden im Bereich und in der Umrandung der Rheinischen Masse an, deren zeitliche Begrenzung nach "oben" an vielen Stellen durch die mächtige Sediment-Decke der trachytischen Asche der Laacher-See-Eruptionen festgelegt ist. Wir nahmen zunächst an, daß die unter den mehrere Meter mächtigen Bims-Decken begrabenen Böden und Sedimente ohne nachträgliche holozäne Veränderungen konserviert worden seien. Im Laufe der angestellten Untersuchungen an den Alleröd-Böden und ihren Ausgangs-Sedimenten wurden wir jedoch belehrt, daß dies nicht der Fall ist. Die in den Bims-Decken ablaufenden V erwitterungs- und Stoff-Abfuhr-Prozesse wirken sich gravierend auf die Unterlage aus, so daß von einer "Fossilierung" im engeren Sinne nicht gesprochen werden kann. Diese Feststellung machte es erforderlich, sich mit den V erwitterungs-Prozessen der Laacher Bims-Ablagerungen auseinanderzusetzen, was in der vorliegenden Arbeit geschehen soll. Die Kenntnis dieser Verwitterungs-Abläufe im Tuff ist darüber hinaus für bodengenetische Betrachtungen im westdeutschen Raum von genereller Bedeutung. Ein erheblicher Teil der allerödzeitlichen Landoberfläche dieses Raumes hat eine m.o.w. starke Beimengung vulkanischer Asche erfahren, die sich bei bodengenetischen Bilanz -Untersuchungen schwer einkalkulieren läßt. Die Ansprache bestimmter Mineral-Neubildungen (wie z.B. Kaolinit, Allophan) als "aschenbürtig" könnte hierbei wichtige Hinweise liefern.

Description: research

Description: Iron-manganese nodules from the ocean floor have been extensively studied. But, because of the fine grain size of the particles of the nodules, structural identification by X-ray and electron diffraction techniques is difficult and the mineralogy of the iron oxide phase has not been well characterized. The observation of the Mössbauer spectrum-in which each nucleus absorbs gamma-rays independently-is not limited by particle size in the same way as is the observation of Bragg peaks in diffraction measurements, in which radiation must be scattered coherently from a large number of atoms. The magnetic hyperfine splitting in the Mössbauer spectrum of magnetic materials is affected, however, when the particles are so small that they become superparamagnetic. We describe here an investigation using the 57Fe Mössbauer effect of two iron-manganese nodules in which the iron oxide phase could not be detected by X-ray or electron diffraction.

Description: The area of distribution of most Myriophyllum species is insufficiently known. In this paper, many new localities are recorded for 16 species from SE. Asia, Malesia, Madagascar, and Africa, and a key is added. One species from New Guinea, M. coronatum, is described as new (fig. I). Of the other species the synonymy is complete, but no descriptions are given; of each the distribution and ecology is cited, and if necessary critical remarks are added.\nUnder the new species the second remark deals with the possible desirability of distinguishing subgenera or sections within the genus. It is concluded that, as the species show a reticulate affinity by parallelism, especially as regards reductions in both vegetative and sexual organs, the usefulness of distinguishing infrageneric taxa is debatable and not advisable.

Description: The type-material of Tachinidae described from Indonesia and housed in the Zoological Museum in Amsterdam is listed, its status determined and its data cited. Twentyfour lectotypes are newly designated for nominal species based on syntypes. Paralectotypes located in other museum collections are recorded for all those nominal species of which the lectotype is in Amsterdam, so as to provide complete information on the original type-material.

Description: 1. A detailed study was made of the subsequent stages in the colour change of the Stoat, Mustela erminea Linnaeus, 1758. 2. Starting and finishing date of both Autumn and Spring moult were determined, based on the examination of 300 pelts from the Netherlands. 3. An indication was found for the existence of a difference in finishing date of the Spring moult in male and female Stoats. The examinations showed that female Stoats complete their summercoat a good month earlier than males. 4. It appeared that there is a remarkable difference in number of completely white animals between warmer and colder parts in the Netherlands. The colder regions hold much more completely white animals. This indicates that temperature has an influence on whether Stoats turn completely white or have a variegated wintercoat.

Description: 1. The real identity has been studied of juvenile gammarids, that were found in the fresh-water tidal region of the River Slack (France), 3 to 4 km inland of the mouth of its estuary. At the outset, these juveniles were (on basis of their morphology) considered to belong to Gammarus salinus. 2. Rearing demonstrated that the juveniles in question developed into adult Gammarus zaddachi. This indicates that the morphological criteria used in discriminating between G. salinus and G. zaddachi fail in juvenile material. Several morphological criteria are discussed and tested. It appears that a 100% certain key character does not exist, meaning that it is not possible to identify with absolute certainty all individuals in mixed populations of the two species. 3. At the same time, the resemblance of juvenile G. zaddachi to adult G. salinus provides us with a morphological feature allowing rapid distinction between adult and juvenile G. zaddachi in studies with large numbers of individuals. 4. In studies of the reproduction and migration of G. zaddachi, several types of nets were developed, both for anadromous and catadromous migrants. These nets agreed with one another in having the same catch capacity. 5. The activity of G. zaddachi shows a diurnal periodicity, the activity peak falling at night.\nThis behavior results in a down-river migration (\xe2\x80\x9cdrift\xe2\x80\x9d), which reaches its maximum 2 to 3 hours after sunset, slowing down later in the night, until the drift virtually stops at sunrise. No influence of the light intensity during the night (moon phase, clouds) was found. 6. During the periods with H.W.S., the direction of the stream reverses in the entire study area. In the parts of the river adjacent to the estuary, this stream reversal is accompanied by a rapid increase in salinity. In the more up-river reaches, no salinity changes occur, so that we find there a fresh-water tidal region. 7. All year round a certain part of the population of G. zaddachi living at a given place (the so-called standing crop) migrates down-river. During the autumn equinoxal spring-tides (and \xe2\x80\x94 though much less \xe2\x80\x94 during the spring equinox) mass migration takes place in up-river direction. This up-river migration takes place only at nights in which the stream reverses under the influence of the H.W.S. Practically exclusively juvenile animals participate in the up-river migration. 8. Per night, the maximum number of animals caught per net (= 30 X 50 cm) was 1,500 downstreamers and 6,000 upstreamers of G. zaddachi, which may roughly correspond with 30,000 downstreamers and 120,000 upstreamers per given section of the river. No other gammarid species in the river Slack shows migratory behavior. 9. Tagging experiments showed, that animals migrating up-river cover distances of 40 to 60 m per night. Downriver migrants cover at least 50 m and at most 80 m per night. 10. Several indications make it plausible that, though G. zaddachi uses the water currents for its migration, the up-river and down-river movements are not merely accidental transportation. Animals in the (physiological) phase of moving down-river continue to do so, irrespective of the direction of the stream. The same holds true for animals in the phase of moving in up-river direction. 11. The reproductive cycle of G. zaddachi is completed in one year. The young appear in spring, in autumn these juveniles grow adult, the first ovigerous females appear in December, the maximum production of eggs falls in the early spring. All adults die after the reproduction period. 12. The reproductive cycle is coupled with the migration cycle. The females participating in down-river migration can, dependent on temperature and salinity, successfully produce an offspring. At temperatures above 7\xc2\xb05C this happens only in the mixohaline parts of the river Slack. When the temperature drops below 7\xc2\xb05 C, egg production is also possible in the limnic reaches of the river. The juveniles pass the summer in the estuarine region. In this season an important portion of the up-river distribution area of G. zaddachi is depopulated. Repopulation of the limnic region by juveniles takes place in the fall, aided by the reversed water currents at H.W.S., thus completing the cycle.

Description: 1. From 54 female fin whales chosen at random from a greater number of animals from which data and material were collected during the Antarctic whaling season 1962/1963, records have been made of the baleen plates and the ear plugs.\nFor the records the complete baleen plates including the part of the plates embedded in the gum are used. All ear plugs used for this study were complete and undamaged. 2. According to their ovaries and baleen records 50 animals were sexually mature, 4 animals were sexually immature. 3. In each individual the record of the complete baleen plate is entirely comparable to the record of the ear plug, in its general trend and in the sequence of peaks and hollows. Also the regular cyclic repetition found in the records of the baleen plates is present in the records of the ear plugs. The comparison of the records of baleen plates with those of ear plugs is only possible when it starts with the last formed part, forming the basis of the core of the plug and the first part of the cortex of the baleen plate deep in the gum, because these represent both the same moment in the life of the animal which is exactly known, viz. the moment in which the growth stopped due to the death of the animal.\nTable III \xe2\x80\x9cGrowth periods\xe2\x80\x9d in the ear plug, per period the mean length number of animals i ii m rv V VI vn VIII IX 4 69 2 53 56 8 62 68 72 8 70 67 73 71 10 63 64 63 61 59 5 59 57 60 63 58 57 6 54 57 61 56 58 58 59 5 69 72 68 67 67 65 65 62 1 66 58 51 62 59 54 49 64 48 total mean 63 64 66 64 60 60 61 63 48 4. In the records of baleen plates and ear plugs of a number of immature animals the \xe2\x80\x9cdouble hump\xe2\x80\x9d or a part of it was found at the right hand side of both. In some of the animals an \xe2\x80\x9covulation peak\xe2\x80\x9d was present at the same time at the beginning (left hand end) in the record of the baleen plate and ear plug; in both in the same position with respect to the surrounding peaks and hollows. This is also true for the records of ear plugs and baleen plates of older females. 5. The records of the ear plugs can be divided into \xe2\x80\x9cgrowth periods\xe2\x80\x9d according to what is done in the records of the baleen plates. In each individual the division between the \xe2\x80\x9cgrowth periods\xe2\x80\x9d in the record of the ear plug are in the same position with respect to the sequence of the surrounding peaks and hollows as is found in the record of the complete baleen plate. In both records the cyclic repetition of peaks and hollows in the successive \xe2\x80\x9cgrowth periods\xe2\x80\x9d is clear. 6. In 21% of the animals examined the number of \xe2\x80\x9cgrowth periods\xe2\x80\x9d in the record of the ear plug is equal to the number present in the record of the baleen plate. In 17% of the animals examined the number of \xe2\x80\x9cgrowth periods\xe2\x80\x9d in the record of the baleen plate was lower (1 to 3 \xe2\x80\x9cgrowth periods\xe2\x80\x9d) than was found in the record of the ear plug. In 62% of the animals examined the number of \xe2\x80\x9cgrowth periods\xe2\x80\x9d in the baleen plate was greater (1 to 6 periods) than was found in the ear plug. 7. Evidence was put foreward that the increase in length of the ear plug is obstructed after the animal has reached a certain age. This moment is not the same for all animals but is probably related to the various \xe2\x80\x9cconstitution types\xe2\x80\x9d present in the catch. It is shown that in the distal end of the ear plug the length of the \xe2\x80\x9cgrowth periods\xe2\x80\x9d suddenly decreases, so only a certain maximum number of \xe2\x80\x9cgrowth periods\xe2\x80\x9d can be found. In the baleen plate the same situation exists due to wear at the tip of the plate. For these reasons the exact age of a fin whale can only be determined as long as wear at the tip of the baleen plate and compression of the distal layers of the ear plug does not occur. 8. From the evidence put foreward it is clear that age determination in fin whales by simply counting the layers present in the core of the ear plug is far too subjective and does not give reliable results. In our opinion best results for age determination in fin whales are obtained by counting the corpora present in the ovaries of females. When this number is divided by the mean ovulation rate (1.25, see Van Utrecht-Cock, 1966) and by adding 6 years (mean number of years before attainment of sexual maturity) the age of the animals calculated in this way is reasonably accurate.