Marine ecology

There are no modem anatomical studies of flipper development or particularly any
examining limb formation across distantly related taxa converging on similar flipper
morphology. This study compares and contrasts the development of flippers in sea turtle
(Caretta caretta) and penguin (Spheniscus demersus , Eudyptula minor) embryos.
Embryos were fixed, cleared and stained for cartilage anlagen, and prepared as whole
mounts. Skeletal elements forming the flipper and changes in their growth rates were
described across developmental stages. Results suggest skeletal elements contribute
differently to sea turtle and penguin flipper blades and there are significant differences in
bone shape and growth patterns. Greater proportional increases in lengths and areas were
found in sea turtles elements compared to penguins. Sea turtles appear to depend on a
pathway resulting in elongation of distal elements to build a flipper, whereas penguin
limbs undergo flattening and expansion of fewer elements to meet a similar structural
goal.

Anthropogenic modifications to' the St. Lucie River watershed have significantly altered
the patterns offreshwater flow, resulting in extreme changes of salinity and the subsequent
decline in the health ofthe estuary. While much is already reported for the response of
Crassostrea virginica to temperature and salinity, distinct differences exist along its distribution
range warranting site specific assessments for previously unstudied populations. A modified
Central Composite Inscribed response surface analysis was designed to describe the response of
the local C. virginica population to a range of endemic salinity and temperature combinations.
Controlled temperature and salinity studies were carried out at the Gumbo Limbo Marine Science
Center in a mesocosm facility specifically designed and constructed for this project.
Condition index and RNA:DNA ratio served as response measures. Minimum values for
condition index were observed at combinations of high temperatures(> 25 °C) and low salinities
(< 5 psu). The analysis of oyster RNA: DNA ratios showed a similar pattern of response,
although, in this case, its relationship with temperature and salinity was not as strong. The final
models for mean condition index and the RNA:DNA ratios explained 77.3% and 35.8% of the
respective variances.

Human activities in the past century have caused a variety of environmental
problems in South Florida. In 2000, Congress authorized the Comprehensive Everglades
Restoration Plan (CERP), a $10.5-billion mission to restore the South Florida ecosystem.
Environmental projects in CERP require salinity monitoring in Florida Bay to provide
measures of the effects of restoration on the Everglades ecosystem. However current
salinity monitoring cannot cover large areas and is costly, time-consuming, and laborintensive.
The purpose of this dissertation is to model salinity, detect salinity changes, and
evaluate the impact of salinity in Florida Bay using remote sensing and geospatial
information sciences (GIS) techniques. The specific objectives are to: 1) examine the
capability of Landsat multispectral imagery for salinity modeling and monitoring; 2)
detect salinity changes by building a series of salinity maps using archived Landsat images; and 3) assess the capability of spectroscopy techniques in characterizing plant
stress / canopy water content (CWC) with varying salinity, sea level rise (SLR), and
nutrient levels.
Geographic weighted regression (GWR) models created using the first three
imagery components with atmospheric and sun glint corrections proved to be more
correlated (R^2 = 0.458) to salinity data versus ordinary least squares (OLS) regression
models (R^2 = 0.158) and therefore GWR was the ideal regression model for continued
Florida Bay salinity assessment. J. roemerianus was also examined to assess the coastal
Everglades where salinity modeling is important to the water-land interface. Multivariate
greenhouse studies determined the impact of nutrients to be inconsequential but increases
in salinity and sea level rise both negatively affected J. roemerianus. Field spectroscopic
data was then used to ascertain correlations between CWC and reflectance spectra using
spectral indices and derivative analysis. It was determined that established spectral
indices (max R^2 = 0.195) and continuum removal (max R^2= 0.331) were not significantly
correlated to CWC but derivative analysis showed a higher correlation (R^2 = 0.515 using
the first derivative at 948.5 nm). These models can be input into future imagery to
predict the salinity of the South Florida water ecosystem.

A brown tide bloom of the pelagophyte Aureoumbra lagunensis caused significant impacts to north Indian River Lagoon (IRL) in 2012-2013, including seagrass die-offs, fish kills, and reduced growth and grazing of ecologically important bivalves. There is potential for another pelagophyte, Aureococcus anophagefferens, to expand into this system. Filtration rates (FR) of the pleated tunicate Styela plicata exposed to Aureoumbra lagunensis and Aureococcus anophagefferens were measured against exposure to a control alga (Tisochrysis lutea) in order to determine its potential use as a bioremediator against these harmful algal blooms (HABs). In addition, whether S. plicata might serve as a vector of HABs was studied by culturing fecal deposits. Short-term exposure to HABs significantly reduced FR, whereas long-term exposure indicates comparable cell removal compared to the control. Vector potential of S. plicata was inconclusive. Results warrant further research to determine whether S. plicata can acclimate or respond to HAB conditions over time.

The sea anemone Aiptasia pallida is a biological model for anthozoan research.
Like all cnidarians, A. pallida possesses nematocysts for food capture and defense.
Studies have shown that anthozoans, such as corals, can rapidly increase nematocyst
concentration when faced with competition or predation, suggesting that nematocyst
production may be an induced trait. The potential effects of two types of tissue damage,
predator induced (Lysmata wurdemanni) and artificial (forceps), on nematocyst
concentration was assessed. Nematocysts were identified by type and size to examine the
potential plasticity associated with nematocyst production. While no significant
differences were found in defensive nematocyst concentration between shrimp predation
treatments versus controls, there was a significant difference in small-sized nematocyst in
anemones damaged with forceps. The proportions of the different types of nematocysts between treatment types were also found to be different suggesting that nematocyst
production in A. pallida is a plastic trait.

Masking or decorator crabs, conceal themselves partially through camouflage, by
selecting or indiscriminately attaching materials from their environment to their
exoskeleton. Functional aspects of decorating behavior and morphology in this group
have not been documented. Using Microphrys bicornutus as a model species, this
dissertation demonstrates clearly that decorating is an advantageous phenotype that has
evolved to serve several functions. Decorating is a complex behavior that begins when a crab approaches an algal substrate and results in the attachment of algae to hooked setae on the exoskeleton. Once decorated, crabs remain motionless on the substrate until disturbed or until another behavior is initiated. This was confirmed for M. bicornutus, as crabs spent a significant
amount of time feeding, remaining motionless, picking, and walking when compared to
decorating. Crabs displayed agonistic behaviors during encounters with conspecifics conspecifics. These included both active aggressive behavior and display behavior.
Crabs showed a decrease in motility during these encounters, helping maintain dispersed
distributions, thereby decreasing intrsapecific encounters in the field. Trials were done to determine the effect of conspecifics, predators and feeding preferences on algal utilization. M. bicornutus showed a significant decrease in the amount of algae used for decoration in the highest density trials (i.e., 4 and 8 crabs). Agonistic displays and aggressive behavior between these crabs likely affected the time available for decorating. Decorated crabs isolated from an algal substrate were more likely to survive in the presence of either of two sympatric fish predators. Thus, being protected by the algal decoration on their exoskeletons. Trials also showed a parallel between algal consumption and algal materials used for decoration. In addition to its protective function, algae used by M. bicornutus for decoration simultaneously serve as
short term food supplies for the crabs. Eleven morphologically complex structures were identified and mapped on the exoskeleton. Hooked setae were the primary structures used to attach algae to the crab’s body. Ten additional setal structures were present, including two novel types of setae. On the basis of location and morphological variation exhibited among these latter structures, a primary sensory function may be inferred.

This project tested the effects of water conditions on developmental rates of larvae of the estuarine sea anemone Nematostella vectensis . Egg masses were collected immediately following fertilization and placed in solutions with different salinities and maintained in a temperature-controlled water bath. Every twelve hours, embryonic development was checked for progression through different morphological stages of development. Comparison of regression analyses of larval development at each temperature increment indicated that both temperature and salinity affected the rate of development; development was slower in lower conditions and faster at higher salinities and temperatures, with extreme conditions inducing deleterious effects. The suggested ideal conditions for these larvae are a salinity range of 12.5--20% and a temperature range of 22--24C. These parameters provide a foundation from which a standardized testing method may be established, using N. vectensis larval development.