A Land-Based Thalassia testudinum Nursery Near Tampa Bay, Florida

An experimental, land-based seagrass nursery, built near Tampa Bay, FL, produced cultivars of Thalassia testudinum Banks and Solander ex König (turtle grass). The nursery was a rectangular basin measuring 6.1 X 12.2 m that graded from 1.5 to 2.0 m in depth constructed inside a fiberglass-covered pole building. The basin had a vinyl liner covered with 10–20 cm of sand and 1.0–1.3 m of water. The nursery ran for 26 mo and focused on producing cultivars of T. testudinum using differing planting techniques. Survival rates were 84% after 3–12 mo in the first planting and 91% after 4 mo in the second planting because early harvesting was required as a result of leaks in the vinyl liner. The planting method that resulted in the highest survival rate was bare rhizomes with two or more short shoots. The cultivars from the two nursery experiments were used in two mitigation projects in Tampa Bay. The nonrecurring cost of the nursery was $12,081.45 over a 3-yr period, and recurring costs are estimated at$22,280.00, with a potential production of 2,500 turf-like 20-cm2 units of T. testudinum that could be sold at $20.00 per planting unit

The Rotational Spectrum and Potential Energy Surface of the Ar-SiO Complex

The rotational spectra of five isotopic species of the Ar-SiO complex have been observed at high-spectral resolution between 8 and 18 GHz using chirped Fourier transform microwave spectroscopy and a discharge nozzle source; follow-up cavity measurements have extended these measurements to as high as 35 GHz. The spectrum of the normal species is dominated by an intense progression of a-type rotational transitions arising from increasing quanta in the Si-O stretch, in which lines up to v = 12 (~14 500 cm-1) were identified. A structural determination by isotopic substitution and a hyperfine analysis of the Ar-Si17O spectrum both suggest that the complex is a highly fluxional prolate symmetric rotor with a vibrationally averaged structure between T-shaped and collinear in which the oxygen atom lies closer to argon than the silicon atom, much like Ar-CO. To complement the experimental studies, a full dimensional potential and a series of effective vibrationally averaged, two-dimensional potential energy surfaces of Ar + SiO have been computed at the CCSD(T)-F12b/CBS level of theory. The equilibrium structure of Ar-SiO is predicted to be T-shaped with a well depth of 152 cm-1, but the linear geometry is also a minimum, and the potential energy surface has a long, flat channel between 140 and 180°. Because the barrier between the two wells is calculated to be small (of order 5 cm-1) and well below the zero-point energy, the vibrationally averaged wavefunction is delocalized over nearly 100° of angular freedom. For this reason, Ar-SiO should exhibit large amplitude zero-point motion, in which the vibrationally excited states can be viewed as resonances with long lifetimes. Calculations of the rovibrational level pattern agree to within 2% with the transition frequencies of normal and isotopic ground state Ar-SiO, and the putative Ka = ±1 levels for Ar-28SiO, suggesting that the present theoretical treatment well reproduces the salient properties of the intramolecular potential