Aquatic Risk Assessment of Metals in Sediment from South Florida Canals

A major watershed restoration effort is underway in south Florida, yet there are significant gaps in scientific information on exposure and risks of contaminants to its natural resources. We conducted a two-tier aquatic screening-level ecological risk assessment for metals that were monitored in sediment at 32 sampling sites in south Florida freshwater canals from 1990–2002. For tier 1, the chemicals (or metals) of potential ecological concern (COPECs) were identified as arsenic, cadmium, chromium, copper, lead, nickel and zinc based on their exceedences of Florida sediment quality guidelines at 10 sites. For tier 2, we used a probabilistic risk assessment method to compare distributions of predicted pore water exposure concentrations of seven metal COPECs with distributions of species response data from laboratory toxicity tests to quantify the likelihood of risk. The overlap of pore water concentrations (90th centile for exposure) for metal COPECs and the effects distributions for arthropods (10th centile of LC50s) and all species (10th centile of chronic NOECs) were used as a measure of potential acute and chronic risks, respectively. Arsenic (25%) in the Holey Land tracts, in Broward County north of Everglades National Park (ENP), and chromium (25%) in the C-111 freshwater system, at the east boundary of ENP, were the most frequently detected COPECs in sediment. Antimony (6%), zinc (6%) and lead (5%) were the least frequently detected COPECs in sediment. The 90th centile concentrations for bulk sediment were highest for zinc (at S-178) and lead (at S-176) in the C-111system. The 90th centile concentration for pore water exposure was highest for arsenic in the Holey Land tracts and lowest for cadmium and chromium. The estimated acute 10th centile concentration for effects was lowest for copper and arthropods. The probabilities of pore water exposures of copper exceeding the estimated acute 10th centile concentration from the species sensitivity distributions (SSD) of acute toxicity data (for arthropods) were 57 and 100% for copper at S-177 and S-178 in the C-111 system, respectively. The probability of pore water exposures of copper exceeding the estimated NOEC 10th centile concentration from the SSD of chronic toxicity data (for all species) was 93 and 100% for copper at S-177 and S-178, respectively. Uncertainties in exposure and effects analysis and risk characterization are identified and discussed. The study presents a straightforward approach to estimate exposure and potential risks of metals detected in sediment from south Florida canals.     

Polymorphic microsatellite loci for Diaprepes root weevil (Diaprepes abbreviatus L.)

Diaprepes abbreviatus (L.) is an insect pest of the US agriculture that originated from the Caribbean islands. Larvae are of economic importance in both nursery and commercial citrus plantings due to root feeding. Eight polymorphic microsatellite markers were developed from a (CA)_n‐enriched genomic library of Diaprepes root weevil. Three to eight alleles were observed for each locus during screening of 17 to 25 individuals. Observed and expected heterozygosities ranged from 0.182 to 0.864 and 0.587 to 0.835, respectively. These markers will be useful to characterize the genetic variability and track the migration patterns of populations of D. abbreviatus (L.).     

Response of the tropical red seaweed Gracilaria cornea to temperature, salinity and irradiance

The agarophyte Gracilaria cornea, collected over 2.5 y in the Florida Keys, shows adaptations to oceanic salinities and subtropical to tropical water temperatures in its photosynthetic and respiratory responses as measured with a respirometer. No seasonal pattern in responses to irradiance, temperature, and salinity were evident between five collections over a 20-month period, indicating the tropical nature of the populations from Bahia Honda and Pigeon Keys. Concentrations of chlorophyll a (0.09 to 0.41 mg g d wt-1) and phycoerythrin (0.06 to 0.36 mg g d wt- 1) were low and reflect the low nutrient regime of the habitats, especially when compared to laboratory cultured plants. Compensation and saturation irradiances were also low (11–38 and 90–127 μmol photon m-2 s-1), indicating acclimation to lower irradiances in their shallow (1–2 m depth) habitats where turbidity can be high. In comparison with other subtropical and warm temperate species of Gracilaria, G. cornea had lower levels of pigment, but similarly high photosynthetic efficiency, demonstrating shade adaptation; it had only limited tolerance to salinities below 20‰ and temperatures below 15 °C. Thus, G. cornea from the Florida Keys in mariculture would require subtropical to tropical temperatures and stable oceanic salinities. This revised version was published online in June 2006 with corrections to the Cover Date.     

Population Genetic Assignment of Confiscated Gopher Tortoises

Abstract As gopher tortoises (Gopherus polyphemus) increasingly become threatened throughout their range in Florida, USA, the need for management and conservation will intensify. Here we evaluate the forensic applicability of genetic assignment tests based on microsatellite genotypic data to 1) accurately assign individuals in our genetic database to the sample location or population of origin and 2) determine the origin of 6 confiscated tortoises. Overall, we could correctly assign 90% of the individuals in the database to their population of origin, but we were unable to determine the source of the confiscated tortoises. However, these individuals are unlikely to have come from any of our sampled sites and all 6 may have come from the same population. This approach can be used by law enforcement personnel to identify the origin of confiscated tortoises as well as by developers and wildlife managers to determine the genetic appropriateness of potential recipient populations when it is necessary to relocate individuals.     

Habitat selection of nesting and fledgling salt marsh songbirds in northeast Florida

Understanding habitat selection by breeding birds and their newly fledged young can be an essential aspect of the conservation of vulnerable species. During 2015–2017, we examined nest site selection of Worthington's marsh wren (Cistothorus palustris griseus) and MacGillivray's seaside sparrow (Ammospiza maritima macgillivraii), and fledgling habitat use by Worthington's marsh wren, 2 imperiled species in northeast Florida, USA. We compared vegetation at unused points to vegetation at nests of both subspecies and at locations used by radio-tagged marsh wren fledglings. Vegetation was taller and stem counts were greater at nest sites compared to unused points. Worthington's marsh wrens also used nest sites with a greater proportion of tall-form smooth cordgrass (Spartina alterniflora) than was observed at unused points. Worthington's marsh wren fledglings also used locations with taller, denser vegetation, but vegetation use changed with fledgling age and tidal stage; older fledglings more frequently used areas with short-form smooth cordgrass and bare ground (and more so during low tides). In contrast, so few nests and nestlings were in black needlerush (Juncus roemerianus) that we could not consider it in our analysis despite its prevalence within our study sites. Our results indicate that tall, dense cordgrass is an important habitat component for these subspecies during the nesting and fledgling life stages in southeastern Atlantic salt marshes.     

Characterizing watercraft-related mortality of sea turtles in Florida

Mortality from being struck by a motorized watercraft is considerable for many aquatic vertebrates around the world, including sea turtles. We studied stranded (i.e., dead, sick, or injured) sea turtles found in Florida, USA, during 1986–2014 and identified those with sharp force or blunt force injuries indicative of a vessel strike. About a third of stranded loggerheads (Caretta caretta), green turtles (Chelonia mydas), and leatherbacks (Dermochelys coriacea) had a vessel-strike injury (VSI). The frequency of this injury was lower but still substantial for stranded Kemp's ridleys (Lepidochelys kempii; 26.1%) and hawksbills (Eretmochelys imbricata; 14.8%). Over the study period, the annual number of stranded loggerheads, green turtles, and Kemp's ridleys with a VSI increased as did the annual number of vessels registered in Florida. Eighty-one percent of the stranded turtles with a VSI were found in the southern half of Florida and 66% of those were found along the southeast coast. By coastal county, the proportion of stranded sea turtles with a VSI was positively related to the mean annual number of registered vessels. The percentage occurrence of a VSI was highest for adult loggerheads, green turtles, and leatherbacks, and reproductively active individuals appeared to be particularly vulnerable to these injuries. We conducted necropsies on 194 stranded sea turtles with a VSI and concluded that this injury was the cause of death or the probable cause of death in ≥92.8% of these cases. During 2000–2014, we estimate that the mean annual numbers of stranded sea turtles that died from a VSI were 142–229 loggerheads, 101–162 green turtles, 16–32 Kemp's ridleys, 4–6 leatherbacks, and 2–4 hawksbills. Considering that only about 10–20% of sea turtles that died likely washed ashore, the overall annual mortality may have been 5–10 times greater than that represented by strandings. Most of the significant clusters of stranded sea turtles with a VSI occurred at inlets or passes and the probability that a stranded sea turtle had a VSI decreased with increasing distance from inlets or passes, navigable waterways, and marinas. We suggest focusing initial management efforts on reducing watercraft-related mortality for all sea turtle species around 8 inlets in southeast Florida, reproductively active loggerheads and green turtles along the coast of southeast Florida, and Kemp's ridleys and adult male loggerheads at passes along the coast of southwest Florida. Published 2019. This article is a U.S. Government work and is in the public domain in the USA. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society     

The role of posttranslational modifications of α-synuclein and LRRK2 in Parkinson's disease: Potential contributions of environmental factors

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's disease (AD), and the most prevalent movement disorder. PD is characterized by dopaminergic neurodegeneration in the substantia nigra, but its etiology has yet to be established. Among several genetic variants contributing to PD pathogenesis, α-synuclein and leucine-rich repeat kinase (LRRK2) are widely associated with neuropathological phenotypes in familial and sporadic PD. α-Synuclein and LRRK2 found in Lewy bodies, a pathogenic hallmark of PD, are often posttranslationally modified. As posttranslational modifications (PTMs) are key processes in regulating the stability, localization, and function of proteins, PTMs have emerged as important modulators of α-synuclein and LRRK2 pathology. Aberrant PTMs altering phosphorylation, ubiquitination, nitration and truncation of these proteins promote PD pathogenesis, while other PTMs such as sumoylation may be protective. Although the causes of many aberrant PTMs are unknown, environmental risk factors may contribute to their aberrancy. Environmental toxicants such as rotenone and paraquat have been shown to interact with these proteins and promote their abnormal PTMs. Notably, manganese (Mn) exposure leads to a PD-like neurological disorder referred to as manganism—and induces pathogenic PTMs of α-synuclein and LRRK2. In this review, we highlight the role of PTMs of α-synuclein and LRRK2 in PD pathogenesis and discuss the impact of environmental risk factors on their aberrancy.     

A new polystomatid (Monogenea,Polystomatidae) from the mouth of the North American freshwater turtle Pseudemys nelsoni

Based on material collected from Pseudemys nelsoni (Reptilia: Chelonia: Emydidae) during a parasite survey of the herpetofauna around Gainesville, Florida, USA, Polystomoides nelsoni sp. n. is described as a new polystome species. This parasite was found in the oral and pharyngeal region of the host. In a sample of nine Pseudemys nelsoni, three specimens were found to release polystome eggs. One turtle was euthanized and dissected and found to be infected in the oral region with 19 specimens belonging to an as-yet-unknown Polystomoides. This is only the fifth Polystomoides recorded from the Nearctic realm. This species is distinguished from known species by a combination of characteristics including marginal hooklet morphology, body length and haptor dimensions.     

The conservation value of elevation data accuracy and model sophistication in reserve design under sea‐level rise

Many studies have explored the value of using more sophisticated coastal impact models and higher resolution elevation data in sea‐level rise (SLR) adaptation planning. However, we know little about to what extent the improved models and data could actually lead to better conservation outcomes under SLR. This is important to know because high‐resolution data are likely to not be available in some data‐poor coastal areas in the world and running more complicated coastal impact models is relatively time‐consuming, expensive, and requires assistance by qualified experts and technicians. We address this research question in the context of identifying conservation priorities in response to SLR. Specifically, we investigated the conservation value of using more accurate light detection and ranging (Lidar)‐based digital elevation data and process‐based coastal land‐cover change models (Sea Level Affecting Marshes Model, SLAMM) to identify conservation priorities versus simple “bathtub” models based on the relatively coarse National Elevation Dataset (NED) in a coastal region of northeast Florida. We compared conservation outcomes identified by reserve design software (Zonation) using three different model dataset combinations (Bathtub–NED, Bathtub–Lidar, and SLAMM–Lidar). The comparisons show that the conservation priorities are significantly different with different combinations of coastal impact models and elevation dataset inputs. The research suggests that it is valuable to invest in more accurate coastal impact models and elevation datasets in SLR adaptive conservation planning because this model–dataset combination could improve conservation outcomes under SLR. Less accurate coastal impact models, including ones created using coarser Digital Elevation Model (DEM) data can still be useful when better data and models are not available or feasible, but results need to be appropriately assessed and communicated. A future research priority is to investigate how conservation priorities may vary among different SLR scenarios when different combinations of model‐data inputs are used.