Growth rates of Corallina officinalis (Rhodophyta) at different temperatures

Specimens of Corallina officinalis L. were grown in the laboratory for 6 and 8 weeks at temperatures of 6°, 12°, 18°, and 25°C. After 6 weeks, the mean growth rates of main axes were 2.8 mm at 18°C, 2.9 mm at 12°C, and 0.2 mm at 5°C; no growth occurred at 25°C. At 6°C, growth increased with lower light intensities. The mean total increase in length of branchlets present when the plants were collected did not vary significantly at 12° and 18°C. At 12°C, axial intergenicula formed in culture produced more new branchlets than did field-grown intergenicula. Also, the production of these branchlets on cultured intergenicula was higher at 12°C than at 18°C.Based on a dissertation completed at Clark University in partial fulfillment of the requirements for a Master of Arts degree by B. J. Colthart.     

Hastigerina pelagica: Foraminiferal habitat for planktonic dinoflagellates

Hand-collection of specimens by SCUBA diving in the Florida Current revealed that the planktonic foraminiferan Hastigerina pelagica harbors on its surfaces 3 species of planktonic dinoflagellates: Pyrocystis fusiformis, P. noctiluca and, predominanty, Dissodinium elegans. Undamaged H. pelagica is unique in possessing a gelatinous, bubble-like capsule completely surrounding the test. While attached to the surface of this capsule, the dinoflagellates frequently reproduced asexually, and appeared healthy in all respects. They were not assimilated by the foraminifera. The number of D. elegans per foraminiferan increased with increased surface area of the gelatinous capsule, averaging approximately 6 dinoflagellates/foraminiferan, with a maximum of 79. Surface-space utilization per D. elegans remained constant with increased foraminiferan size. The use of the foraminifera in a facultative commensal or symbiotic association and the value of surfaces in that association is postulated.     

A WATER POLICY-LAND USE COMPUTER SIMULATION MODEL1

ABSTRACT: This paper describes the philosophy, algorithms, and implementation of a computer-oriented land use forecasting-water policy simulation model. The model is applicable to SMSA's organized on a census tract basis by counties. The forecasts are macro to the census tract level for industrial, residential, commercial and public land uses, and are dynamically altered by hypothesized water management policies. Modeling is based on an economic data base of the region, and is extremely flexible for the user. An example set of simulations is included for illustrative purposes.     

Growth of Uronema marinum in chemically defined medium

A strain of the marine hymenostome ciliate Uronema marinum was isolated in axenic culture. This strain, designated PW2, was cultivated in a chemically defined medium containing 17 amino acids, 4 nucleotides, 5 fatty acids, stigmasterol, 8 growth factors and an artificial sea water. Increased populations were observed when either phosphatidylinositol or Tween 80 were included in the medium. The vitamins thiamine, riboflavin, pyridoxal, nicotinamide, folic acid and pantothenate were required by U. marinum PW2. No requirement could be demonstrated for exogenous thioctic acid or biotin, although growth was diminished in their absence. The amino acid and nucleotide requirements were found to be higher than the levels reported for other ciliates. This strain was found to be euryhaline, with maximum growth observed in media of specific gravity 1.007, corresponding to approximately 25% sea water. Although no requirement could be demonstrated for Fe, Zn, Mn or Cu, high levels of these metals were observed to be toxic. Growth was observed over a pH range of 6.6 to 8.3, with an optimum observed near 7.3.     

Taxonomic revisions in the marine biflagellate fungi: The ultrastructural evidence

The ultrastructure of the genera Althornia, Aplanochytrium, Japonochytrium, Schizochytrium and Thraustochytrium is described, and all are regarded as members of the new order Thraustochytriales Sparrow. Species considered are Althornia crouchii, Aplanochytrium kerguelensis, Hyalochlorella marina, Japonochytrium sp., Schizochytrium aggregatum, Thraustochytrium kinnei and T. striatum. All but H. marina are, on ultrastructural evidence, related genera, and some speculative suggestions are made about possible interrelationships both between the species discussed, between the Thraustochytriales and Labyrinthulales, and between these two and other major taxa.