Algal Colonies Research Articles

Distribution of nitrogen-fixing bacteria in the Central Pacific Ocean

The plate culture method using the two formulae for non-nitrogenous media was adopted in this investigation for the purpose of counting and isolating nitrogen-fixing bacteria distributed in the open sea.Sea water samples were collected at eighteen different stations in the region of Lat. 50°N–15°S along Long. 155°W and two other stations in the Pacific Ocean. In order to compare with those samples from the open sea, water samples were also obtained at four stations in Suruga and Sagami Bays.Nitrogen-fixing bacteria appear to be widely but very unevenly distributed at all depths in sea water, in numbers approximately ranging from nil to 104 per 100 ml of sea water, and denser vertical populations have been found in the area of Lat. 40°N and 5°N along Long. 155°W, even at depths from 2,000 to 3,000m. A conparatively denser population of bacteria was found in sea water from Suruga Bay and Sagami Bay.The bacteria associated with plankton were abundantly demonstrated, in numbers ranging from 106 to 108 per 1 ml settling volume of plankton, in many plankton samples collected at four stations in the southern parts of the Pacific Ocean. Almost all the bacteria isolated from the samples of blue green algal colonies,Trichodesmium, sp., were able to grow on nonnitrogeneous media.

Ferroan and Non-Ferroan Calcite Cements in Pleistocenerecent Carbonates from the New Hebrides

ABSTRACT Petrographic study of stained Pleistocene-Recent biolithites from Erromango reveals an advanced state of diagenesis. Micrite is produced by grain diminuton of algal colonies, and probably by fragmental abrasion. Other fabrics developed include granular mosaics and simple syntaxial rims. In samples collected from carbonates sandwiched between volcanic ash bands, two phases of cementation are apparent. The first phase cement is composed of ferroan calcite, which is followed by a second phase of non-ferroan calcite cement. Ferroan calcite is previously unrecorded as a cement in Recent carbonates, and in addition it is very rare as a first stage cement in ancient carbonates. Diagenesis of these carbonate sediments has produced in a very short time a hard, compact, partially recrystallized rock. Reasons for this advanced state of diagenesis are unknown, but in all probability they are connected with the high heat values in the rocks resulting from contemporaneous volcanicity.

The environmental history of the Boulonnais, France

The Boulonnais region of northern France contains surface exposures of rocks ranging in age from Silurian to Recent. Silurian graptolitic shales are followed by a varied succession of Middle and Upper Devonian shoreline and shallow shelf deposits. Faunal and sedimentological sequences display repeated phases of shallowing and deepening water. The Carboniferous Limestones include a remarkable development of algal colonies and forms a karst surface which is usually covered by Mesozoic continental and shallow marine deposits. The Upper Jurassic displays repeated shallowing and emergence with local conglomerates, trace fossil sequences and sandstone diapirs leading to a final fresh-water episode preceding continental Wealden and an Upper Cretaceous succession very like that of south-east England. Unexposed outliers of Eocene, loose blocks of Pliocene sands similar to the Lenham Beds, Quaternary raised beach and solifluxion deposits complete the record apart from recent blown sand and river deposits.

'Grain-diminution' of algal colonies to micrite

Studies of Recent and Paleozoic calcareous algal deposits indicate that early diagenetic alteration can result in a change of calcareous algal filaments and cells to cryptocrystalline calcium carbonate. The apparent absence of reef framework builders of some of the enigmatic micritic to fine-grained bioherms or knoll-reefs of North America, Europe, and Australia, may be explained by 9grain diminution9 of calcareous algal colonies.

Pure Culture of Anabaena flos-aquae A-37

SEVERAL methods have been proposed for the isolation of bacteria-free cultures of algae1–6. Methods reported to provide some measure of success, using antibiotics, ultraviolet light, chlorine compounds, etc., are fairly drastic and, in some cases, mutagenic. The problem of separating algae from bacteria may be related to a binomial distribution function in which the probability of choosing a bacteria-free algal colony in any trial varies in an unknown fashion from one trial to another. Successful, practical use of the proposed method may be expected only when the chance of choosing a bacteria-free algal colony exceeds about one in twenty.

Stromatolitic Bioherms in the Maynardville (Upper Cambrian) Limestone, Tennessee

The upper Cambrian Maynardville limestone was investigated through a strike length of 8½ miles in Jefferson and Sevier counties, Tennessee. A detailed composite columnar section shows five zones in the formation, from the base upward: (1) interbedded limestone and shale, (2) massive Stromatolitic limestone, (3) oolitic and conglomeratic limestone, with thin Stromatolitic beds, (4) massive and thick-bedded limestone, with a few dolomitic and Stromatolitic layers, and (5) thin- to medium-bedded dolomite, with very little limestone. Extensive Stromatolitic bioherms in Zone 2 contain subcircular forms, presumably the fossil outlines of algal colonies. Many intercolony fillings are composed of calcareous oolites and clastic sediments in a fine-grained calcitic matrix; others consist of dolomite and calcareous shale. Similar Stromatolitic limestones were found in eight other outcrop belts of the Maynardville in East Tennessee. Five localities are listed where the algal colonies are well exposed in the outlying belts.

Counting soil algae by direct fluorescence microscopy.

THE dilution technique is not entirely satisfactory in studying soil algae. There is no universal medium for their growth, nor can we assume that all species will grow on any artificial medium now in use. The slow growth of algal colonies involves delays of up to two or three months, causing inconvenience in routine work. Filamentous and colonial algae introduce further difficulties. A single filament or colony can give one or many colonies according to the number of viable pieces formed from it during dispersion. Available data on the number of algae in the soil cannot therefore be regarded as absolutely certain.

On the use of antibiotics for isolating bacteria-free cultures of marine phytoplankton organisms

In the course of some studies on the kinetics of growth and the biochemical activities of a marine diatom it became desirable to obtain bacteria-free cultures. The classical method of obtaining such pure algal cultures involves either repeatedly washing single cells in sterile medium or obtaining discrete bacteria-free algal colonies by growth on a solid medium. Both these methods have been widely applied to fresh-water species by Pringsheim (1946) and others, whilst Chu (1946) has used both methods with the marine diatom Nitzschia closterium (Ehrenberg) Wm. Smith forma minutissima.

SOME REEF-BUILDING CALCAREOUS ALGAE FROM THE CARBONIFEROUS ROCKS OF NORTHERN ENGLAND AND SOUTHERN SCOTLAND

( Read, February , 1948). The various growth-forms assumed by algal colonies are described and it is suggested that they are determined primarily by environmental factors. A study of the sediments associated with these growth-forms indicates that reef-building algae flourished in shallow, disturbed water, rich in silica and iron. Periods of vulcanicity appear to produce an environment favourable to algal growth. Three main algal phases in the Lower Carboniferous rocks of northern England and southern Scotland are described,—the main Algal Series of C1, the Burdiehouse Limestone horizon in S1 and the Girvanella -bearing limestones at the top of D1. A number of new growth-forms are described. According to Pia’s classification of the fossil algae ( in Hirmer, 1927) the group Spongiostromata includes the more massive reef-building forms such as Weedia Walcott, Collenia Walcott, Cryptozoon Hall, Archaeozoon Matthew, Gymnosolen Steinmann, Pycnostroma Gurich, Wingia Seely, Osagia Twenhofel, Ottonosia Twenhofel and Spongiostroma Gurich. With the exception of Spongiostroma these generic names refer to a variety of growth forms, which, it is suggested, represent the remains of algal colonies. When Pia’s account was published none of these, with the possible exception of Cryptozoon , could be demonstrated to possess any undoubted algal structures such as are seen in the similar, but more recent, Corallinaceae (e.g. Lithothamnium ). The recent work of Johnson (1946), however, has shown that some of these growth-forms represent the shapes assumed by the aggregate of a number of algal filaments not always all of the same kind, which suggests that they are the remains of ...

Cambrian Calcareous Algae from Pennsylvania

These series contain four distinct forms of algal colonies, or deposits. The partly dolomitized specimens do not show whether the original material was finely clastic sediment entrapped by 'gelatinous coverings of the algae, or was precipitated because of algal life processes.t There also is no indication as to how many species may have cooperated in the production of each colonial form, though they probably were several. Despite this probability, we recognize them as form-species, for these reasons: