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Williams A.A.,Guana Tolomato Matanzas National Estuarine Research Reserve | Williams A.A.,University of North Florida | Williams A.A.,Louisiana State University | Eastman S.F.,Guana Tolomato Matanzas National Estuarine Research Reserve | And 7 more authors.
Southeastern Naturalist | Year: 2014

The northern limits of three mangrove species-Avicennia germinans (Black Mangrove), Rhizophora mangle (Red Mangrove), Laguncularia racemosa (White Mangrove)-on the United States Atlantic coast are vouchered and described in comparison to previous boundaries defined in literature and herbarium collections. The location and general status of individual trees were used to delineate northern maxima and show that present ranges extend beyond historic records. The gradient structure of the ecotone within an area of uniform climate is interpreted as ongoing latitudinal movement.


Williams A.A.,University of North Florida | Williams A.A.,Guana Tolomato Matanzas National Estuarine Research Reserve | Williams A.A.,Louisiana State University | Kimball M.E.,University of North Florida | And 2 more authors.
Environmental Monitoring and Assessment | Year: 2013

The Nassau River estuary is located in northeast Florida adjacent to the eutrophic St. Johns River. Historically, development has been sparse in the Nassau River's catchment; thus, the system may provide a relatively undisturbed aquatic environment. To monitor the condition of the Nassau River estuary and to discern spatial and temporal trends in water quality, nutrients and hydrographic variables were assessed throughout the estuary from 1997 to 2011. Hydrographic (temperature, salinity, total suspended solids, and turbidity) and nutrient parameters (total phosphorus, ortho-PO4 3-, total nitrogen, NH4 +, total Kjeldahl nitrogen, and NO 3 -) were monitored bimonthly at 12 sites in the mesohaline and polyhaline zones of the river. Nonparametric Kendall's Tau was implemented to analyze long-term water quality patterns. Salinity was found to increase with time, particularly in the mesohaline sampling sites. Dissolved oxygen decreased over time in the estuary and hypoxic conditions became increasingly frequent in the final years of the study. Nutrients increased in the estuary, ranging from 149 to 401 %. Rainfall data collected in adjacent conservation areas did not correlate well with nutrients as compared with stream discharge data collected in the basin headwaters, outside of the conservation lands, attributed here to expanding urbanization. During the study period, the Nassau basin underwent rapid human population growth and land development resulting in commensurate impacts to water quality. Nutrient and physical data collected during this study indicate that the Nassau River estuary is becoming more eutrophic with time. © 2013 Springer Science+Business Media Dordrecht.


Badylak S.,University of Florida | Phlips E.,University of Florida | DIx N.,Guana Tolomato Matanzas National Estuarine Research Reserve | Hart J.,University of Florida | And 7 more authors.
Marine and Freshwater Research | Year: 2016

Concerns about global climate change have heightened awareness of the role changing rainfall regimes play in altering plankton communities of coastal ecosystems. In this study spatial and temporal patterns of phytoplankton composition and biomass in a sub-tropical tidal creek in Florida were observed over three wet and dry seasons, which included the major storm year of 2005 and the drought year of 2006. Shifts in rainfall levels were associated with changes in phytoplankton composition and biomass, but the effects varied between the upper and lower reaches of the creek. The upper reach of the creek was fresh throughout the study period. The oligohaline to mesohaline lower creek alternated between fresh and marine species in response to shifts in salinity regimes. Blooms of the freshwater dinoflagellate Peridinium sp., small centric diatoms and nitrogen-fixing cyanobacteria were common in the upper Ten Mile Creek during low rainfall years. The euryhaline marine dinoflagellate Akashiwo sanguinea and centric diatoms (e.g. Leptocylindrus minimus) were observed at bloom levels in the lower creek during low to average rainfall periods. The results are discussed within the context of how variability in rainfall influence water residence times, nutrient concentrations and salinity regimes, which in turn influence phytoplankton composition and biomass. © CSIRO 2016.


Hart J.A.,University of Florida | Phlips E.J.,University of Florida | Badylak S.,University of Florida | Dix N.,Guana Tolomato Matanzas National Estuarine Research Reserve | And 4 more authors.
Marine Environmental Research | Year: 2015

The primary objective of this study was to examine trends in phytoplankton biomass and species composition under varying nutrient load and hydrologic regimes in the Guana Tolomato Matanzas estuary (GTM), a well-flushed sub-tropical estuary located on the northeast coast of Florida. The GTM contains both regions of significant human influence and pristine areas with only modest development, providing a test case for comparing and contrasting phytoplankton community dynamics under varying degrees of nutrient load. Water temperature, salinity, Secchi disk depth, nutrient concentrations and chlorophyll concentrations were determined on a monthly basis from 2002 to 2012 at three representative sampling sites in the GTM. In addition, microscopic analyses of phytoplankton assemblages were carried out monthly for a five year period from 2005 through 2009 at all three sites. Results of this study indicate that phytoplankton biomass and composition in the GTM are strongly influenced by hydrologic factors, such as water residence times and tidal exchanges of coastal waters, which in turn are affected by shifts in climatic conditions, most prominently rainfall levels. These influences are exemplified by the observation that the region of the GTM with the longest water residence times but lowest nutrient loads exhibited the highest phytoplankton peaks of autochthonous origin. The incursion of a coastal bloom of the toxic dinoflagellate Karenia brevis into the GTM in 2007 demonstrates the potential importance of allochthonous influences on the ecosystem. © 2015 Elsevier Ltd.


PubMed | St. Johns River Water Management District, University of Florida, Georgia Southern University and Guana Tolomato Matanzas National Estuarine Research Reserve
Type: Journal Article | Journal: Marine environmental research | Year: 2015

The primary objective of this study was to examine trends in phytoplankton biomass and species composition under varying nutrient load and hydrologic regimes in the Guana Tolomato Matanzas estuary (GTM), a well-flushed sub-tropical estuary located on the northeast coast of Florida. The GTM contains both regions of significant human influence and pristine areas with only modest development, providing a test case for comparing and contrasting phytoplankton community dynamics under varying degrees of nutrient load. Water temperature, salinity, Secchi disk depth, nutrient concentrations and chlorophyll concentrations were determined on a monthly basis from 2002 to 2012 at three representative sampling sites in the GTM. In addition, microscopic analyses of phytoplankton assemblages were carried out monthly for a five year period from 2005 through 2009 at all three sites. Results of this study indicate that phytoplankton biomass and composition in the GTM are strongly influenced by hydrologic factors, such as water residence times and tidal exchanges of coastal waters, which in turn are affected by shifts in climatic conditions, most prominently rainfall levels. These influences are exemplified by the observation that the region of the GTM with the longest water residence times but lowest nutrient loads exhibited the highest phytoplankton peaks of autochthonous origin. The incursion of a coastal bloom of the toxic dinoflagellate Karenia brevis into the GTM in 2007 demonstrates the potential importance of allochthonous influences on the ecosystem.


Nifong J.C.,University of Florida | Nifong R.L.,University of Florida | Silliman B.R.,University of Florida | Lowers R.H.,InoMedic Health Applications | And 5 more authors.
PLoS ONE | Year: 2014

Large-bodied, top- and apex predators (e.g., crocodilians, sharks, wolves, killer whales) can exert strong top-down effects within ecological communities through their interactions with prey. Due to inherent difficulties while studying the behavior of these often dangerous predatory species, relatively little is known regarding their feeding behaviors and activity patterns, information that is essential to understanding their role in regulating food web dynamics and ecological processes. Here we use animal-borne imaging systems (Crittercam) to study the foraging behavior and activity patterns of a cryptic, largebodied predator, the American alligator (Alligator mississippiensis) in two estuaries of coastal Florida, USA. Using retrieved video data we examine the variation in foraging behaviors and activity patterns due to abiotic factors. We found the frequency of prey-Attacks (mean = 0.49 prey attacks/hour) as well as the probability of prey-capture success (mean = 0.52 per attack) were significantly affected by time of day. Alligators attempted to capture prey most frequently during the night. Probability of prey-capture success per attack was highest during morning hours and sequentially lower during day, night, and sunset, respectively. Position in the water column also significantly affected prey-capture success, as individuals' experienced two-fold greater success when attacking prey while submerged. These estimates are the first for wild adult American alligators and one of the few examples for any crocodilian species worldwide. More broadly, these results reveal that our understandings of crocodilian foraging behaviors are biased due to previous studies containing limited observations of cryptic and nocturnal foraging interactions. Our results can be used to inform greater understanding regarding the top-down effects of American alligators in estuarine food webs. Additionally, our results highlight the importance and power of using animal-borne imaging when studying the behavior of elusive large-bodied, apex predators, as it provides critical insights into their trophic and behavioral interactions. © 2014 Nifong et al.


Eash-Loucks W.E.,Guana Tolomato Matanzas National Estuarine Research Reserve | Kimball M.E.,Guana Tolomato Matanzas National Estuarine Research Reserve | Kimball M.E.,University of South Carolina | Petrinec K.M.,Guana Tolomato Matanzas National Estuarine Research Reserve
Journal of Crustacean Biology | Year: 2014

Along the US Atlantic coast, oyster reefs support a large number of estuarine species including ecologically important and abundant mud crabs. Multiple factors including environmental conditions, the introduction of non-native species, parasites, and interspecific competition can change the structure of these communities over time. To examine long-term changes in mud crab communities, crabs were sampled quarterly for ten years in a mixed oyster/mud habitat in a northeast Florida estuary. A total of 6935 individuals comprised of 10 species were collected, including two non-native crab species: Petrolisthes armatus (Gibbes, 1850) and Charybdis hellerii (Milne-Edwards, 1867). Three species (Panopeus herbstii Milne Edwards, 1834, P. armatus, and Eurypanopeus depressus (Smith, 1869)) made up 97.3% of adult specimens collected, and were observed throughout the study period in varying abundances. Non-metric multi-dimensional scaling (MDS) conducted on species abundances revealed that the community underwent significant long-term, rather than cyclical seasonal, changes. Most noteworthy were the similarities in community assemblages observed in the years prior to, and soon after, the introduction of a nonnative parasite, Loxothylacus panopaei (Gissler, 1884), which preferentially infects E. depressus. The significance of the presence/absence of the parasite on the community structure was confirmed through an analysis of similarities test (ANOSIM). While E. depressus abundance declined in the early years of the study after the introduction of L. panopaei, and never recovered, abundance of P. herbstii did not significantly change. Temperature and salinity likely only briefly impacted individual species on a seasonal or yearly basis including P. armatus, whose abundance reached an all-time low in the winter of 2010-2011 along with extreme winter temperatures. © 2014 The Crustacean Society.


Eash-Loucks W.E.,University of Kansas | Eash-Loucks W.E.,Guana Tolomato Matanzas National Estuarine Research Reserve | Fautin D.G.,University of Kansas
Zootaxa | Year: 2012

Sea anemones sensu lato (members of cnidarian orders Actiniaria and Corallimorpharia) occurring in water of the northeastern Pacific Ocean greater than 1,000 m (to the abyssal plain) are poorly known. Based on the literature and specimens we examined in the four largest collections of animals from this area, we estimate that approximately 35 species occur in these deep-water habitats and fewer than half have been documented there. Of the largest and most abundant epibenthic species, based on morphology, we identified two species of Corallimorpharia (both previously known) and 12 of Actiniaria (three new). Half the sea anemone species are widely distributed: Actinauge verrillii McMurrich, 1893, Actinoscyphia groendyki n. sp., Actinostola faeculenta (McMurrich, 1893), Bathyphellia australis Dunn, 1983, Liponema brevicorne (McMurrich, 1893), Metridium farcimen (Brandt, 1835), and Monactis vestita (Gravier, 1918). The others are known only from the northeastern Pacific Ocean: Corallimorphus pilatus Fautin, White, and Pearson, 2002, Corallimorphus denhartogi Fautin, White, and Pearson, 2002, Anthosactis nomados White, Wakefield Pagels, and Fautin, 1999, Bolocera kensmithi n. sp., Paraphelliactis pabista Dunn, 1982, Sagartiogeton californicus (Carlgren, 1940) (for which we designate a neotype), and Sicyonis careyi n. sp. A naturally occurring oxygen minimum zone (OMZ) off Oregon is expanding, and the marine life living within its virtually anoxic areas is threatened. Nine of the species we examined occur within the current depth range of the OMZ and may be threatened if the OMZ continues to strengthen and expand. © 2012 Magnolia Press.

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