GHSIM Developed in Spreadsheet Quattro Pro Simulates the Interactive Greenhouse

A computer model, GHSIM, was formulated in Quattro Pro spreadsheet format. GHSIM was designed having individual pages calculating simulated activities necessary for greenhouse production. Pages were arranged by alphabetical topics starting with the “Area” used in the greenhouse. Time advanced by 1 day for each 10 s of real time. The time advance in the program can be paused to make setting changes interactively. Pest infestation occurred as probabilities accumulated, and the pest population spread through the greenhouse based on proximity and density of pests. Pest control was simulated by a pesticide application capable of partially reducing populations; repeated applications could effectively eliminate a pest. Crop growth was simulated by iterative acccumulation of biomass using Euler integration of daily plant growth. The daily growth increment was calculated using the first derivative of the Richard's Function. Large pest populations negatively impacted the daily growth increment, and pesticide applicaions would remove the inhibition of growth. Additional features proposed include light and temperature effects on the plant growth rate and accumulated biomass.

Effects of temperature on growth of the Japanese spiny lobster, Panulirus japonicus (V. Siebold) phyllosomas under laboratory conditions

The effects of temperature on growth of phyllosomas of the Japanese spiny lobster Panulirus japonicus were investigated. Phyllosomas were individually reared at four temperatures (20°, 22°, 24° and 26°C), and intermoult period and moult increment were monitored. The improved Bêlehrádek’s equation, G = aLb (T–α)c(β–T)d, was used to describe the relationship between growth characters (G: intermoult period, moult increment or daily growth increment), body length (L) and temperature (T), with a and b being constants that change at 17·8 mm body length, c and d being common constants for all sizes, and α and β being the conceptual biological lower and upper critical temperatures, which are variables with body length. The intermoult period increased and the moult increment decreased with decreasing temperature. However, a negative influence on both the intermoult period and the moult increment was observed at 26°C for medium-sized and large phyllosomas. The largest daily growth increment was obtained at 26°C up to 15·0 mm body length, and then at 24°C. This indicates that the optimum temperature for growth decreases from 26° to 24°C at 15·0 mm body length. This optimum temperature for growth seemed to be optimal for survival.

Effects of pH on the early development and growth and otolith microstructure of chinook salmon, Oncorhynchus tshawytscha

Chinook salmon (Oncorhynchus tshawytscha) eggs, alevins, and fry were reared in pH 4.5, 5.0. 5.5, 6.2 (control), and 7.0 water from the eyed stage of development. Survival through hatching was >90% in all instances. Alevin mortality was high at pH 4.5 and 5.0. Fry were more tolerant of low pH than alevins. Growth rates of alevins and fry held at or above pH 5.0 and 4.5, respectively, were not affected by pH, nor did exposure to acidic water retard otolith development or result in their resorption. One otolith daily growth increment was formed every 24 h in alevins and fry irrespective of pH. Widths of otolith daily growth increments decreased when fry were transferred to pH 4.5 water and increased on their return to higher pH indicating changes in growth rate. Transfer of fry from pH 6.2 to pH 5.0 or 5.5 had no effect on increment widths.

Biological and environmental rhythms reflected in molluscan shell growth

Tidal cycles are reflected in daily growth-increment sequences in shells of many Recent and fossil mollusks. Living specimens of the bivalve Mercenaria mercenaria were notched at the growing edge of the shell and planted intertidally in Barnstable Harbor, Massachusetts. Shells from two lots, killed at intervals of 368 and 723 days after planting, show the same number of small growth increments as there were days from notching to killing. Superimposed on daily growth record are effects of winter (thin daily increments) and tides (14-day cycles of thick and thin daily increments). Comparison of Barnstable tide record with the first year's growth shows that, for each 14-day cycle, thin daily increments form during neap tides and thicker daily increments form during spring tides. Although tidal patterns are present in subtidal Mercenaria shells, they are rarely as pronounced as in intertidal ones. Spawning patterns differ from winter patterns; they are expressed in the shell by an interruption of regular deposition followed by a series of thin daily increments. Continuous sequences of bidaily patterns, one thick daily increment followed by a relatively thin one, are common in M. mercenaria.The clearest 14-day cycles of deposition were seen in shells of the bivalve Tridacna squamosa. Each daily neap-tide increment is a simple layer consisting of a dark and light zone. Each daily spring-tide increment is a complex layer consisting of two light-dark alternations separated by a depositional break that is more pronounced than the breaks delimiting daily intervals. Preliminary results of growth-increment counts in fossils show a generally decreasing trend of the mean values of days per lunar month toward the Recent. The Pennsylvanian value is 30.07 ± 0.08, a figure that is in general agreement with those of Scrutton (1964), who counted 30.59 days per month on Devonian corals, and Barker (1966), who reported more than 30 days per month in Pennsylvanian bivalves.