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1999 Special Awards Winners
State Science and Engineering Fair of Florida
April 7-9, 1999
The Lakeland Center, Lakeland

animated globe FDACS Senior / FDACS Junior

Awards Given By The Florida Department of Agriculture and Consumer Services
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Senior Section

Aaron C. Richardson
East Panhandle
Category: Environmental Science
Teacher: Mr. Stan Bosenberg, Walton Senior High School
Award: $1,000 Savings Bond and Plaque
Project Title: Insecticidal Interference: Is it a Threat to Rhizobia's Nitrogen Fixation Role?

Project Synopsis:
Insecticidal Interference: Is it a Threat to Rhizobias Nitrogen Fixation Role?

This project was performed to determine if agricultural use of certain insecticides would negatively affect Rhizobias nitrogen fixation role in legumes. It was hypothesized the insecticides tested would have a negative affect on Rhizobias nitrogen fixation role by decreasing the growth rates of the legumes tested.

Three genera of legumes were tested: clover, soybeans, and vetch. Three test groups were made for the insecticides Phorate, Orthene and Sevin. Each chemical group divided into nutrient groups "Nitrogen Free" or "Complete." Two seed types were tested within these groups and were referred to as "treated" (inoculated) or "untreated." Equal temperature, pot size, water / nutrient amount, sunlight, and soil type were used for the plants. Plants were exposed to Sevin and Orthene sprays14 and 29 days after planting. Phorate was added to Phorate groups at planting time. Height and leaf color observations were made.

Results were based on plant growth rate and suggested Phorate insecticide was devastating to Rhizobia. Few negative effects were noted on plants in Orthen and Sevin groups. Many Phorate group plants either did not germinate or demonstrated very little growth.

Findings indicated some types of insecticides are safe for use with Rhizobia. Farmers wishing to use Rhizobia inoculation with legumes should find safe use with Sevin, Orthene, or similar chemicals. Phorate use or similar insecticides would ne discouraged due to the negative effect to Rhizobia. Insecticides should be carefully selected by farmers when planning Rhizobia inoculation as a means to increase nitrogen levels in plants.

Junior Section

Kristinia L. Anderson
Category: Environmental Science
Teacher: Mrs. Guytri B. Still, Ronald McNair Magnet School
Award: $1,000 Savings Bond and Plaque
Project Title: Biotic Relationships Between Mercenaria mercenaria and Modiolus modiolus

Project Synopsis:
Biotic Relationships between Mercenaria mercenaria and Modiolus modiolus

The objective of this experiment is to determine how the introduction of the Northern Horse Mussel into a clam aquaculture setting affects the survival and success of the two species. This is of interest to clam aquaculturists attempting to raise clams (Mercenaria mercenaria) in containment devices which are susceptible to infestation by the mussel Modiolus modiolus.

Three tests were performed at different locations for increased accuracy. Three trays were prepared for each test.: one with a combination of M. mercenaria and M. modiolus, one as a control containing only M. mercenaria, and one as a control containing only M. modiolus. Observations were recorded weekly. Included in the observations for each tray were: exterior appearance of the tray, estimated largest and smallest size of each species, photograph and sketch of the interior spatial organization, and verbal description of progress from previous week.

The test was continued for eight weeks. At then end of this period, each test subject was measured using a caliper. Statistical analysis were calculated to determine whether the size difference between populations of comparable trays was significant. Samples of test and control organism were examined in detail and with a microscope.

The results showed that clams growth was significantly less when with mussels than when alone, when compared to the 99th percent level. The mussels at site "C" were found to be significantly larger in size than the control containing only mussels at that site. Those at site "A" were not statistically different in size, although the mean size for the mussels was greater in the trays containing both populations.

In conclusion, the infestation of M. modiolus into a clam aquaculture system is detrimental to the growth of the clams, and beneficial to some extent for the mussels. Therefore, the two species, Mercenaria mercenaria and Modiolus modiolus, do interact with one another in an aquacultural setting. For the clams, the relationship is competitive. For the mussels, the aquaculturist in a situation similar to the one illustrated here. Thus, it is in the best interests of aquaculturists to attempt to avoid mussel introduction.

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