Oyster Abundance in Apalachicola Bay, Florida in Relation to Biotic Associations Influenced by Salinity and Other Factors

From June 1955 through May 1957, stations on three oyster reefs were sampled quantitatively at intervals and all oysters and associated macroscopic organisms were recorded per unit area. Station I was a privately leased “natural” reef, consisting of higher places exposed at low water, with a salinity range of 22.7-36.6 o/oo and was fairly productive. Station II, depth ca. two meters, was the least saline, range 1.2-29.3 o/oo, and was considered very productive for natural reef. Station III, depth one meter, salinity range 7.5-35.7 o/oo, was depleted although there was an abundant spatfall. Depth and bottom types as well as salinity were found to delimit certain species of animals. Analysis of past records showed that the bay had formerly been less saline; there was an extended drought in the watershed before and during the investigation. As a result several species of animals less euryhaline than oysters became established on some of the reefs. At Station III, two serious oyster enemies, Thais haemastoma Say and Menippe mercenaria Conrad were abundant. A field experiment at this station during the second year pointed to these two enemies as the main cause of the depletion of the reef. Near the end of the investigation rainfall became more nearly normal and the lowest salinities were recorded at this time. The reduction in salinity, especially at Station III, eliminated many of the less euryhaline species, including drills and stone crabs, and the reef later regained its former productivity

Oyster Abundance in Apalachicola Bay, Florida in Relation to Biotic Associations Influenced by Salinity and Other Factors

From June 1955 through May 1957, stations on three oyster reefs were sampled quantitatively at intervals and all oysters and associated macroscopic organisms were recorded per unit area. Station I was a privately leased “natural” reef, consisting of higher places exposed at low water, with a salinity range of 22.7-36.6 o/oo and was fairly productive. Station II, depth ca. two meters, was the least saline, range 1.2-29.3 o/oo, and was considered very productive for natural reef. Station III, depth one meter, salinity range 7.5-35.7 o/oo, was depleted although there was an abundant spatfall. Depth and bottom types as well as salinity were found to delimit certain species of animals. Analysis of past records showed that the bay had formerly been less saline; there was an extended drought in the watershed before and during the investigation. As a result several species of animals less euryhaline than oysters became established on some of the reefs. At Station III, two serious oyster enemies, Thais haemastoma Say and Menippe mercenaria Conrad were abundant. A field experiment at this station during the second year pointed to these two enemies as the main cause of the depletion of the reef. Near the end of the investigation rainfall became more nearly normal and the lowest salinities were recorded at this time. The reduction in salinity, especially at Station III, eliminated many of the less euryhaline species, including drills and stone crabs, and the reef later regained its former productivity

Temporal structure of stimulated-Brillouin-scattering reflectivity considering transversal-mode development

The time-resolved reflectivity of optical phase conjugation by stimulated Brillouin scattering ~SBS! is investigated both theoretically and experimentally. A three-dimensional and transient model of SBS is developed to compare the experimental and theoretical results. Noise initiation of the SBS process is included in the model to simulate the shot-to-shot variation in the reflectivity and the Stokes temporal profile.Shahraam Afshaarvahid, Axel Heuer, Ralf Menzel, and Jesper Munc

Developing a predictive modelling capacity for a climate change-vulnerable blanket bog habitat: Assessing 1961-1990 baseline relationships

Aim: Understanding the spatial distribution of high priority habitats and developing predictive models using climate and environmental variables to replicate these distributions are desirable conservation goals. The aim of this study was to model and elucidate the contributions of climate and topography to the distribution of a priority blanket bog habitat in Ireland, and to examine how this might inform the development of a climate change predictive capacity for peat-lands in Ireland. Methods: Ten climatic and two topographic variables were recorded for grid cells with a spatial resolution of 1010 km, covering 87% of the mainland land surface of Ireland. Presence-absence data were matched to these variables and generalised linear models (GLMs) fitted to identify the main climatic and terrain predictor variables for occurrence of the habitat. Candidate predictor variables were screened for collinearity, and the accuracy of the final fitted GLM was evaluated using fourfold cross-validation based on the area under the curve (AUC) derived from a receiver operating characteristic (ROC) plot. The GLM predicted habitat occurrence probability maps were mapped against the actual distributions using GIS techniques. Results: Despite the apparent parsimony of the initial GLM using only climatic variables, further testing indicated collinearity among temperature and precipitation variables for example. Subsequent elimination of the collinear variables and inclusion of elevation data produced an excellent performance based on the AUC scores of the final GLM. Mean annual temperature and total mean annual precipitation in combination with elevation range were the most powerful explanatory variable group among those explored for the presence of blanket bog habitat. Main conclusions: The results confirm that this habitat distribution in general can be modelled well using the non-collinear climatic and terrain variables tested at the grid resolution used. Mapping the GLM-predicted distribution to the observed distribution produced useful results in replicating the projected occurrence of the habitat distribution over an extensive area. The methods developed will usefully inform future climate change predictive modelling for Irelan

Letter to Henryk B. Stenzel from R.W. Menzel on 1968-01-11

Jackson School of Geoscience

Letter to H.B. Stenzel from R.W. Menzel on 1961-07-26

Jackson School of Geoscience

Letter to H.B. Stenzel from R.W. Menzel on 1961-08-03

Jackson School of Geoscience

Letter to H.B. Stenzel from R.W. Menzel on 1967-09-20

Jackson School of Geoscience