Plankton Studies V. The Plankton of the Illinois River, 1894-1899. Part II. Constituent Organisms and Their Seasonal Distribution

This paper gives the results of a statistical study of a series of quantitative plankton collections made in the channel of the Illinois River near Havana, Ill., at the Illinois Biological Station, in 1894-1899. The environmental conditions and the volumetric results of this investigation have been given in Part I. (Kofoid, '03), published in Volume VI. of this Bulletin.published or submitted for publicationis peer reviewe

Morphology of Gambierdiscus excentricus (Dinophyceae) with emphasis on sulcal plates

Gambierdiscus excentricus is an epibenthic dinoflagellate able to produce ciguatoxin and maitotoxin-like compounds that are responsible for ciguatera fish poisoning. Morphological descriptions and molecular characterization of two G. excentricus strains isolated from Brazil and maintained in culture were provided. The most complete description of the morphology of the sulcal region of Gambierdiscus based on light and scanning electron microscopy was presented. The sulcal area morphology and nomenclature used by different authors to name the sulcal plates in Gambierdiscus were reviewed. Two small sulcal plates (S.m.a. and S.m.p.) were shown for the first time. Phylogenetic trees based on D1–D3 and D8–D10 large subunits of ribosomal RNA gene sequences showed that the strains of G. excentricus from Brazil clustered with strains of G. excentricus isolated from its type locality, the Canary Islands. Both phylogenetic trees reconstructed the same relationships among all the formally described Gambierdiscus species and Gambierdiscus sp. ribotype 2 and Gambierdiscus sp. type 2.Versión del editor2,080

Plankton Studies. 1. Methods and Apparatus in use in plankton investigations at the Biological Experiment Station of the University of Illinois.

Less than ten years ago a new field of biological science was opened by the German investigator Hensen, namely, the quantitative examination of the " Plankton." This term was applied to all plants and animals floating free in the water and incapable by their own efforts of materially changing their position. Thus adult fish which ])rave the waves and stem the current would not be included in the plankton, while the passive eggs or the helpless fry would fall within the limits of the definition. Practically, the content of the term plankton as applied to fresh water is the sum total of its minute life, both plant and animal.Ope

Plankton Studies II On Pleodorina illinoiensis, A New Species from the Plankton of the Illinois River

The genus Pleodorina was discovered in 1893 by Shaw ('94) at Palo Alto, California, and in May of the following year the species Pleodorina californica, upon which the genus was founded, was detected by Mottier ('94) in water from a shallow stagnant pool near Bloomington, Indiana. During the same summer the form also occurred in the Illinois River and its adjacent waters (Clinton, '94), and it has been found in the plankton of these situations in succeeding years from Tune to September. The distribution of the species in this continent is thus quite extended, and it is not at all improbable that continued investigation of fresh-water plankton will demonstrate that this genus has a cosmopolitan distribution similar to that of some other genera of the family Volvocineae to which it belongs.Ope

Plankton Studies III. On Platydorina, A New Genus of the Family Volvocidae, from the Plankton of the Illinois River

The family Volvocidce is well represented in the plankton of fresh-water ponds and streams. Indeed, with the possible exception of Steplianosphera, all of the colonial forms included in the subfamily Volvocince—Spondylomoruni , Gonium, Stephanosphcera , Pandorina, Pleodorina, and Volvox — are pelagic in habit and are found only in the fresh-water environment. For the past four years, during the summer and autumn months, a colonial form belonging to this subfamily has occured in plankton collections from the Illinois River and its adjacent waters, to which I have given the name of Platydorina caudata. It appears as early as June 15, and becomes abundant in the months of August and September, diminishing in numbers in October, and disappearing in November.Ope

Plankton Studies IV. The Plankton of the Illinois River, 1894-1899, with Introductory Notes Upon the Hydrography of the Illinois River and Its Basin. Part I. Quantitative Investigations and General Results

When the work of the Illinois Biological Station was begun in lS94r. it seemed to the Director desiralile to determine as far as possible the normal routine of aquatic life as a necessary basis for the detection of problems for investigation and experiment, and as an indispensable background for their adequate solution. Such an investigation demands not only the discovery and specific determination of the biological population, Init involves also the study of life histories, seasonal changes, and mutual dependencies of the assembled organisms by quantitative and statistical methods, together with a study of the environment and an analysis of its factors. The plankton presented itself as the most available and concrete assemblage of organisms to which this method of study could be applied, and it afforded, moreover, a prolilem not only of prime scientific interest, but also of some important practical relation to fish culture. A presentation of the most general results of this investigation of the free microscopic fauna and flora, or plankton, of this typical stream of the Mississippi Valley is the object of the present paper.Ope