Epizooic Diatoms on the Cerci of Ephemeroptera (Caenidae) Naiads

Using scanning electron microscopy, epizooic diatoms were observed growing on the cerci of Caenis amica Hagen naiads (Ephemeroptera, Caenidae). Meridion circulare (Greville) C. Agardh was the most abundant, followed by Synedra rumpens Kützing, then Cocconeis pediculus Ehrenberg. Other diatom species observed from substrates in Cedar Creek, Isabella County, Michigan were not observed on the cerci. No diatoms were observed on Ephemerellidae naiads

Ultrastructure of Flagellated Chrysophytes. IV. Chrysosphaerella

Information on the fine structure of naturally occurring cells of Chrysosphaerella brevispina and C. longispina is given and some new data are presented. The ultrastructure is generally typical for the Chrysophyceae although both perinuclear cisternae and cytoplasmic endobiotic bacteria occur. A paraflagella rod occurs in the photoreceptor area of the short, second flagellum. Siliceous scale and bristle origin are illustrated

Ultrastructure of Flagellated Chrysophytes. IV. Chrysosphaerella

Information on the fine structure of naturally occurring cells of Chrysosphaerella brevispina and C. longispina is given and some new data are presented. The ultrastructure is generally typical for the Chrysophyceae although both perinuclear cisternae and cytoplasmic endobiotic bacteria occur. A paraflagella rod occurs in the photoreceptor area of the short, second flagellum. Siliceous scale and bristle origin are illustrated

Freshwater Silica-Scaled Heterotrophic Protista: Heliozoa, Thaumatomonad Flagellates, Amoebae, and Bicosoecids, from the Lake Itasca Region, Minnesota

Forty-nine plankton samples were collected from the Lake Itasca Region, Minnesota over a period sporadically covering the summers of 1980, 1981 and 1987. A total of 22 freshwater heterotrophic siliceous-scaled species were observed: 18 heliozoa, two thaumatomonad flagellates, one bicosoecid, and one testate amoeba. Scale identifications were based on transmission electron microscopy. New records for North America include two heliozoans and one thaumatomonad flagellate. Five heliozoa taxa and one thaumatomonad flagellate are new records for the U.S. Wujek DE. Freshwater silica-scaled heterotrophic protista: heliozoa, thaumatomonad flagellates, amoebae, and bicosoecids, from the Lake Itasca Region, Minnesota

The Diatom Flora of the Red Lake Peatland, Minnesota

Diatoms collected from three transects in the Red Lake Peatland occur in characteristic assemblages. One hundred two taxa were observed from 26 sample sites, with Eunotia exigua and Pinnularia rupestris the most dominant species. Clustering indicated three peatland types were present: rich fen, transitional and poor fen, and bog

Results of REXUS12's Suaineadh Experiment : Deployment of a spinning space web in micro gravity conditions

On the 19th of March 2012, the Suaineadh experiment was launched onboard the sounding rocket REXUS12 (Rocket Experiments for University Students) from the Swedish launch base ESRANGE in Kiruna. The Suaineadh experiment served as a technology demonstrator for a space web deployed by a spinning assembly. The deployment of this web is a stepping stone for the development of ever larger structures in space. Such a structure could serve as a substructure for solar arrays, transmitters and/or antennas. The team was comprised of students from the University of Strathclyde (Glasgow, UK), the University of Glasgow (Glasgow, UK) and the Royal Institute of Technology (Stockholm, Sweden), designing, manufacturing and testing the experiment over the past 24 months. Following launch, the experiment was ejected from the ejection barrel located within the nosecone of the rocket. Centrifugal forces acting upon the space webs spinning assembly were used to stabilise the experiment’s platform. A specifically designed spinning reaction wheel, with an active control method, was used. Once the experiment’s motion was controlled, a 2 m by 2 m space web is released. Four daughter sections situated in the corners of the square web served as masses to stabilise the web due to the centrifugal forces acting on them. The four daughter sections contained inertial measurement units (IMUs). Each IMU provided acceleration and velocity measurements in all three directions. Through this, the positions of the four corners could be found through integration with respect to known time of the accelerations and rotations. Furthermore, four cameras mounted on the central hub section captured high resolution imagery of the deployment process. After the launch of REXUS12, the recovery helicopter was unable to locate the ejected experiment, but 22 pictures were received over the wireless connection between the experiment and the rocket. The last received picture was taken at the commencement of web deployment. Inspection of these pictures allowed the assumption that the experiment was fully functional after ejection, but perhaps through tumbling of either the experiment or the rocket, the wireless connection was interrupted. A recovery mission in the middle of August was only able to find the REXUS12 motor and the payload impact location

Scaled Chrysophytes from the Lake Itasca Region. III: Additions to the Flora

Eighteen localities within Itasca State Park, Minnesota, were sampled in 1987 and examined for silica-scaled chrysophytes. Sixteen species from six genera, including seven new reports for Minnesota, were observed. Brief comments on distribution are given for several species. Recent taxonomic revisions for a number of previously reported species from the Lake Itasca region are also discussed

Studies on Silica-Scaled Chrysophytes from Iowa

References in the literature to the silica-scaled chrysophytes of Iowa are few and, since the advent of the electron microscope, identifications of taxa in this group are no longer considered valid without accompanying electron micrographs. Using scanning electron microscopy for critical identifications, eight taxa genera of the Synuraceae are reported here including the first known report of the genus Paraphysomonas from Iowa. From the other two genera, Mallomonas and Synura, only one of the taxa in this paper, Mallomonas pseudocoronata, has been reported from Iowa previously. Mallomonas acaroides var. striatula, M. tonsurata, M. tonsurata var. alpina, M. teilingii, M. pseudocorcnata, Mallomonas sp., Synura petersenii, and Paraphysomonas imperforata are the taxa reported

Scaled Chrysophycae From Lake Itasca Region I. Mallomonas

By means of electron microscopy, phytoplankton samples from the Lake Itasca region were examined for the silica-scaled chrysophycean genus Mallomonas. Seventeen taxa were observed: 15 are new for Minnesota, of these 15, seven are also new reports for the continental United States