Seascape Connectivity of Gulf Sturgeon \u3ci\u3eAcipenser oxyrinchus desotoi\u3c/i\u3e Population Units Across the Northern Gulf of Mexico

Critical habitat was designated in 2003 for federally threatened anadromous Gulf sturgeon to aid in population recovery. This study examined overwintering Gulf sturgeon spatial use and movement through critical habitat monitored by the Ship Island acoustic array from 2011 to 2015. Previous studies observed western population Gulf sturgeon (Pearl and Pascagoula rivers) overwintering near the ends and within the passes of the barrier islands of the Mississippi Sound, USA. Recent telemetry studies detected eastern population fish (Escambia, Blackwater, Yellow, and Choctawhatchee rivers) overwintering as far west as Mobile Bay, Alabama; however, this study is the first to observe eastern population fish overwintering in western population critical habitat associated with the Ship Island array. Use of overwintering habitat was compared using mean active days detected and rate of travel to and from the array. There was no significant difference in mean active days of population units on the array; however, travel rate to the array from natal drainages was significantly different, with eastern population individuals traveling at a faster rate compared to western population individuals. Post hoc tests indicated that individuals from the Blackwater River had a significantly higher travel rate compared to Pascagoula River individuals. We documented large-scale seascape connectivity among population units of Gulf sturgeon across the northern Gulf of Mexico. Although large-scale seascape connectivity promotes mixing among population units and an exchange of marine nutrients into riverine environments, large-scale migration poses an issue for endangered species such as Gulf sturgeon, as there is greater risk of bycatch mortality and size-specific predation

Correlation of DIAL Ozone Observations with Lightning

The purpose of this project is to see whether ozone maxima measured by the DIfferential Absorption Lidar (DIAL) instrument in Huntsville, AL may be traced back to lightning events occurring 24 48 hours beforehand. The methodology is to start with lidar measurements of ozone from DIAL as well as ozonesonde measurements. The HYbrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model is then used to determine the origin of these ozone maxima 2448 hours prior. Data from the National Lightning Detection Network (NLDN) are used to examine the presence/absence of lightning along the trajectory. This type of analysis suggests that lightningproduced NOx may be responsible for some of the ozone maxima over Huntsville

Survival, Growth and Reproduction of Non-Native Nile Tilapia II: Fundamental Niche Projections and Invasion Potential in the Northern Gulf of Mexico

Understanding the fundamental niche of invasive species facilitates our ability to predict both dispersal patterns and invasion success and therefore provides the basis for better-informed conservation and management policies. Here we focus on Nile tilapia (Oreochromis niloticus Linnaeus, 1758), one of the most widely cultured fish worldwide and a species that has escaped local aquaculture facilities to become established in a coastal-draining river in Mississippi (northern Gulf of Mexico). Using empirical physiological data, logistic regression models were developed to predict the probabilities of Nile tilapia survival, growth, and reproduction at different combinations of temperature (14 and 30°C) and salinity (0–60, by increments of 10). These predictive models were combined with kriged seasonal salinity data derived from multiple long-term data sets to project the species\u27 fundamental niche in Mississippi coastal waters during normal salinity years (averaged across all years) and salinity patterns in extremely wet and dry years (which might emerge more frequently under scenarios of climate change). The derived fundamental niche projections showed that during the summer, Nile tilapia is capable of surviving throughout Mississippi\u27s coastal waters but growth and reproduction were limited to river mouths (or upriver). Overwinter survival was also limited to river mouths. The areas where Nile tilapia could survive, grow, and reproduce increased during extremely wet years (2–368%) and decreased during extremely dry years (86–92%) in the summer with a similar pattern holding for overwinter survival. These results indicate that Nile tilapia is capable of 1) using saline waters to gain access to other watersheds throughout the region and 2) establishing populations in nearshore, low-salinity waters, particularly in the western portion of coastal Mississippi

Immunomodulatory Roles of CTRP3 in Endotoxemia and Metabolic Stress

C1q/TNF-related protein 3 (CTRP3) is a secreted hormone that modulates hepatic glucose and lipid metabolism. Its circulating levels are reduced in human and rodent models of obesity, a metabolic state accompanied by chronic low-grade inflammation. Recent studies have demonstrated an anti-inflammatory role for recombinant CTRP3 in attenuating LPS-induced systemic inflammation, and its deficiency markedly exacerbates inflammation in a mouse model of rheumatoid arthritis. We used genetic mouse models to explore the immunomodulatory function of CTRP3 in response to acute (LPS challenge) and chronic (high-fat diet) inflammatory stimuli. In a sublethal dose of LPS challenge, neither CTRP3 deficiency nor its overexpression in transgenic mice had an impact on IL-1β, IL-6, TNF-α, or MIP-2 induction at the serum protein or mRNA levels, contrary to previous findings based on recombinant CTRP3 administration. In a metabolic context, we measured 71 serum cytokine levels in wild-type and CTRP3 transgenic mice fed a high-fat diet or a matched control low-fat diet. On a low-fat diet, CTRP3 transgenic mice had elevated circulating levels of multiple chemokines (CCL11, CXCL9, CXCL10, CCL17, CX3CL1, CCL22 and sCD30). However, when obesity was induced with a high-fat diet, CTRP3 transgenic mice had lower circulating levels of IL-5, TNF-α, sVEGF2, and sVEGFR3, and a higher level of soluble gp130. Contingent upon the metabolic state, CTRP3 overexpression altered chemokine levels in lean mice, and attenuated systemic inflammation in the setting of obesity and insulin resistance. These results highlight a context-dependent immunomodulatory role for CTRP3

Evidence of Spawning Capable Tarpon (Megalops atlanticus) Off the Louisiana Coast

Despite the fact that the tarpon (Megalops atlanticus) is a popular sport fish in the Gulf of Mexico (GOM; Ault et al. 2008), little is known of its spawning behavior. Spawning M. atlanticus have never been documented and fertilized eggs have not been observed in situ (Ault et al. 2008). While it has been suggested that adult M. atlanticus move to deep water off the southwest coast of Florida and into the Yucatan Channel to spawn, the actual locations of spawning grounds remain unknown (Smith 1980, Crabtree et al. 1995, Crabtree et al. 1997). Distribution patterns of larvae (leptocephali) have served as the basis for most of what has been inferred about the spawning areas (Smith 1980, Crabtree et al. 1997). For example, leptocephali were collected from the southwestern GOM, the Yucatan Channel, and along the west coast of Florida, and based on the their size, it was assumed that M. atlanticus spawned in nearby areas (Smith 1980). Histological examination of gonads has also been used to estimate the location of M. atlanticus spawning habitat. Females collected from the Florida Keys and Boca Grande Pass off the west coast of Florida and contained ovaries with post ovulatory follicles (POF) and advanced vitellogenic oocytes, suggesting M. atlanticus spawn in this region from April through July (Crabtree et al. 1997). Examination of gonads from M. atlanticus caught off the coast of equatorial Ceara State, Brazil suggested that spawning occurs there from October through January (de Menezes and Paiva 1966). We report here the first evidence of spawning capable M. atlanticus off the coast of Louisiana in the northern GOM based on histological examination of gonads

Variation of a Lightning NOx Indicator for National Climate Assessment

During the past couple of years, an analysis tool was developed by the NASA Marshall Space Flight Center (MSFC) for the National Climate Assessment (NCA) program. The tool monitors and examines changes in lightning characteristics over the conterminous US (CONUS) on a continual basis. In this study, we have expanded the capability of the tool so that it can compute a new climate assessment variable that is called the Lightning NOx Indicator (LNI). Nitrogen oxides (NOx = NO + NO2) are known to indirectly influence our climate, and lightning NOx is the most important source of NOx in the upper troposphere (particularly in the tropics). The LNI is derived using Lightning Imaging Sensor (LIS) data and is computed by summing up the product of flash area x flash brightness over all flashes that occur in a particular region and period. Therefore, it is suggested that the LNI is a proxy to lightning NOx production. Specifically, larger flash areas are consistent with longer channel length and/or more energetic channels, and hence more NOx production. Brighter flashes are consistent with more energetic channels, and hence more NOx production. The location of the flash within the thundercloud and the optical scattering characteristics of the thundercloud are of course complicating factors. We analyze LIS data for the years 2003-2013 and provide geographical plots of the time-evolution of the LNI in order to determine if there are any significant changes or trends between like seasons, or from year to year