Sea level rise and the associated inland shift of the marsh-mangrove ecotone in south Florida have raised many scientific and management concerns in recent years. Holocene paleoecological records can ...provide an important baseline to shed light on the long-term dynamics of vegetation changes across this ecotone in the past, which is needed to predict the future. In this study, we present palynological, X-ray fluorescence, and loss-on ignition data from four sedimentary cores recovered from a 20-km marine-to-freshwater transect along the Shark River Estuary, southwest Everglades, to document the patterns and processes of coastal vegetation changes in response to sea level rise since the mid-Holocene. Our record indicates that freshwater marsh progressively replaced marl prairies at the Shark River Estuary between 5700 and 4400 cal yr BP. As marine transgression continued, marine influence reached the threshold necessary for mangroves to establish at the current mouth of the Shark River Slough at 3800 cal yr BP. During the next 3000 years, although sea level rise in the Western North Atlantic slowed down to 0.4 mm/yr, a spatial and temporal gradient was evident as the marsh-mangrove ecotone shifted inland by 20 km from 3800 to 800 cal yr BP, accompanied by a gradual landward replacement of freshwater marsh by mangrove forest. If sea level continues to rise at 2.33 mm/yr in the 21st century in south Florida, it is possible that marine influence will reach the threshold for mangroves to establish in the central Everglades, and we could expect a much more aggressive mangrove encroachment toward the northern and interior parts of south Florida in the next few centuries.
Four sedimentary facies may be delineated based on quantitative analysis of texture and composition of modern surface sediments on the Dry Tortugas carbonate platform. These include (1) ...mollusk-Halimeda wackestone, (2) mollusk packstone-to-grainstone, (3) coralgal-Halimeda grainstone, and (4) coralgal grainstone. Even though the Tortugas platform is characterized by an open circulation due to deep, broad marginal channels and a lack of a continuous surface-breaking marginal reef, facies are not distributed at random and show bathymetrical zonation. Also, facies appear to cover wide belts rather than forming a mosaic. Mollusk-Halimeda wackestone occurs in protected platform interior areas ca. 10–18m deep. Mollusk packstone-to-grainstone occurs in more open platform interior settings adjacent to channels and in deeper outer reef areas of 14–25m water depth. Coralgal-Halimeda grainstone is found on shallow marginal shoals (1–11m deep), and coralgal grainstone on the somewhat deeper (3–16m), seaward edges of these shoals. However, there is bathymetrical overlap of facies in intermediate depths of ca. 5–17m. This limitation has implications for the interpretation of the fossil record, because changes in water depth are commonly thought to be reflected in facies changes, e.g., in sequence stratigraphy. Comparison with previous sediment studies of the 1930s, 1960s, and 1970s in the area exhibit a decrease in coral fragments and increases in coralline algal and mollusk shell fragments. These observations might be a result of environmental changes such as coral decline and die-outs during temperature events, disease, and the increase in macroalgae (due to the ecological extinction of the echinoid Diadema). The results suggest that more long-term studies are needed that further explore the influence of environmental change on reef sediment composition. Dry Tortugas surface sediments consist of lower portions of Halimeda plates and mollusk shell fragments and higher percentages of coralline algal fragments as compared to sediments of the adjacent Florida Reef Tract, possibly as a consequence of differences in platform morphology and exposure to waves and currents.
•Four facies delineated based on quantitative analysis of texture and composition of modern sediments on Dry Tortugas.•Facies are not distributed at random and show bathymetrical zonation.•Decrease in coral and increases in coralline algal and mollusk constituent particles as result of environmental changes.•More long-term studies are needed that explore influence of environmental change on reef sediment composition.
Surface moisture content is an essential factor that must be considered when studying aeolian sediment transport on a sandy beach. In recent years, near-infrared (NIR) remote sensing sensors have ...shown promise for obtaining accurate surface moisture data; however, prior studies utilized instruments with extreme costs. This study assesses the capability of an inexpensive NIR digital camera to measure surface moisture at two sandy beach environments – Tybee Island, Georgia and Pensacola Beach, Florida – that exhibit varying sediment hue characteristics. To account for temporal variations in solar atmospheric conditions, we normalized the raw sediment surface reflectance data against a white reflectance card and a sample of oven dry sand representative of each study site. This is a necessary step to account for solar atmospheric conditions. Calibration results illustrate that the NIR camera is capable of producing accurate representations of beach surface moisture; analyses from both study sites produced R2 values greater than 0.76 with error estimates at ±1–2% moisture. No statistical difference in calibration relationships were observed for data collected over multiple days and times of day. Calibration data for the reflectance card produced more robust relationships with smaller prediction errors than the oven dry sand analyses; however. Overall, this study illustrates that an inexpensive digital camera modified to record NIR radiation is capable of producing robust and accurate measurements of beach surface moisture.
•Inexpensive near-infrared camera capable of accurately recording surface moisture•Data compares with research using more expensive near-infrared devices.•Necessary to account for changes in solar atmospheric conditions•No statistical difference in data collected over different days and times of day
One of the challenging tasks in modern aquatic remote sensing is the retrieval of near-surface concentrations of Total Suspended Solids (TSS). This study aims to present a Statistical, inherent ...Optical property (IOP) -based, and muLti-conditional Inversion proceDure (SOLID) for enhanced retrievals of satellite-derived TSS under a wide range of in-water bio-optical conditions in rivers, lakes, estuaries, and coastal waters. In this study, using a large in situ database (N > 3500), the SOLID model is devised using a three-step procedure: (a) water-type classification of the input remote sensing reflectance (Rrs), (b) retrieval of particulate backscattering (bbp) in the red or near-infrared (NIR) regions using semi-analytical, machine-learning, and empirical models, and (c) estimation of TSS from bbp via water-type-specific empirical models. Using an independent subset of our in situ data (N = 2729) with TSS ranging from 0.1 to 2626.8 g/m3, the SOLID model is thoroughly examined and compared against several state-of-the-art algorithms (Miller and McKee, 2004; Nechad et al., 2010; Novoa et al., 2017; Ondrusek et al., 2012; Petus et al., 2010). We show that SOLID outperforms all the other models to varying degrees, i.e.,from 10 to >100%, depending on the statistical attributes (e.g., global versus water-type-specific metrics). For demonstration purposes, the model is implemented for images acquired by the MultiSpectral Imager aboard Sentinel-2A/B over the Chesapeake Bay, San-Francisco-Bay-Delta Estuary, Lake Okeechobee, and Lake Taihu. To enable generating consistent, multimission TSS products, its performance is further extended to, and evaluated for, other missions, such as the Ocean and Land Color Instrument (OLCI), Moderate Resolution Imaging Spectroradiometer (MODIS), Visible Infrared Imaging Radiometer Suite (VIIRS), and Operational Land Imager (OLI). Sensitivity analyses on uncertainties induced by the atmospheric correction indicate that 10% uncertainty in Rrs leads to <20% uncertainty in TSS retrievals from SOLID. While this study suggests that SOLID has a potential for producing TSS products in global coastal and inland waters, our statistical analysis certainly verifies that there is still a need for improving retrievals across a wide spectrum of particle loads.
•Model (SOLID) is developed for estimating TSS in coastal/inland waters.•Validated with a wide range of trophic/turbidity conditions•Performance is thoroughly gauged against five other models.•Model produces stable performance in optically complex aquatic ecosystems.•Performance is assessed for several satellite missions.
Thai basil (Ocimum basilicum var. thyrsiflora) is an important ethnic aromatic herb native to Southeast Asia. According to the Vegetable Production Handbook of Florida 2020-2021, Asian vegetables are ...currently grown on more than 4,000 ha in Florida, and Thai basil is one of the most commonly grown among these. Meloidogyne spp. cause severe damage to different basil cultivars (Brito et al. 2007). During May-July 2020, plant stunting and galled root symptoms were observed on Thai basil plants sampled from a commercial Asian vegetable farm in Wimauma, Florida (27°44.951' N; 82°16.271' E); 1,972 root-knot nematode second-stage juveniles (J2s) were extracted from 200 cm3 soil. A pathogenicity test was performed in September 2020 at the University of Florida Gulf Coast Research and Education Center, Wimauma, Florida. Ten of 20, three-week-old nematode-free Thai basil plants were inoculated with 5,000 eggs of field nematode cultures. Two months after inoculation (temperature = 22.8 ± 3.8 °C, relative humidity = 85.6 ± 14.0 %), average gall index (Bridge and Page 1980) = 5.4 ± 1.1 were only observed in inoculated plants, and 69,276 ± 18,904 eggs were extracted from roots using the NaClO method (Hussey and Barker 1973); 5 ± 7 J2s / 200 cc soil were recovered by the modified Baermann funnel technique (Forge and Kimpinski 2007). Nematode reproduction factor (RF) = 13.86 ± 3.78 (Nicol et al. 2010). Morphological measurements (mean, standard deviation and range) of J2s (n=20) included body length = 394.0 ± 22.3 (362.8 - 437.9) µm, body width = 15.7 ± 1.2 (13.6 - 18.3) µm, and stylet length = 12.8 ± 1.1 (10.4-14.5) µm. The perineal pattern of matured female (n=5) was oval-shaped with coarse and smooth striate; the dorsal arch was high and round; no lateral line presented. Morphological characteristics of females and J2s were consistent with those described for M. enterolobii (Yang and Eisenback 1983). DNA was extracted from a single female picked from infected Thai basil root using NaOH digestion method (Hübschen et al. 2004). The D2-D3 expansion segment of 28S rDNA and the COXII region on mitochondrial DNA were amplified by PCR using the primers 28S391a/28S501 and C2F3/1108 (Ye et al. 2020); the species was also confirmed with species-specific primers Me-F/Me-R (Ye et al. 2020). PCR products were sequenced by the Genomic Sciences Laboratory (North Carolina State University, Raleigh, NC, USA) and the results were recorded in the NCBI with GeneBank Accession Nos. MW488150 and MW507374. The sequences showed 100% identity with M. enterolobii in D2/D3 (KP901079, KP411230) and COXII (MN809527, KX214350). M. enterolobii (M. mayaguensis) has been reported on sweet basil in Florida (Brito et al. 2008). To our knowledge, this is the first detection of M. enterolobii on Thai basil in Hillsborough County, Florida. It is not clear to what extent M. enterolobii reduces the yield of Thai basil, but the RF value obtained in the pathogenicity test indicates the crop is certainly a very good host. Limited information is available on the distribution of M. enterolobii in Florida and the US. M. enterolobii is known to break down the root-knot resistance of crops including soybean, sweet potatoes, and tomatoes (Philbrick et al. 2020). This nematode is considered one of the major emerging threats to agriculture in the southeastern US. A multistate research and outreach program (FINDMe program) was initiated in 2019 to study the distribution and management of this nematode in the southeastern US.
Cold-water coral ridges with waveform morphology are commonly observed in mound surfaces in the Northeast Atlantic Ocean and interpreted as sediment waves overgrown by corals. This work documents the ...first cold-water coral ridges that are waveform but lack sand dune cores. These coral ridges are situated at the base of the Miami Terrace in the Straits of Florida (depths of 630 to 870m). They are entirely biogenic in origin and are unrelated to antecedent topography. Five lines of evidence, based on 27km2 of high-resolution geophysical, oceanographic, and ground-truthing data, support this interpretation. First, the waveform coral ridges are aligned perpendicular to a southward flowing bottom current and juxtaposed to an active sand dune field devoid of corals. Both the coral ridges and sand dunes are asymmetric in profile with respect to the current. However, the ridges have their steep sides facing the current, whereas the dunes exhibit a steep leeside. Second, the coral ridge matrix consists of very fine sand to mud particles with no bedload sand transport on the ridge flanks or troughs. In contrast, active sand ripples superimpose the juxtaposed sand dunes indicating that coarse sand is transported via traction in this domain. Third, bedload sand transport occurs in linear streaks at the shallowest part of the surveyed area. These streaks orthogonally crosscut some coral ridges, but coral colonies are not aligned along these streaks. Instead, the bedload sand smothers the coral colonies and thereby segments the ridges. Fourth, the sand dune and coral ridge acoustic responses are different. Below the dunes, there is no sub-bottom reflection due to energy attenuation. In contrast, a continuous reflection below the coral ridges proves the absence of attenuating sand cores. Fifth, this continuous sub-bottom reflection is not correlated with the coral ridge topography, indicating that antecedent topography does not control the waveform morphology and spatial distribution of the ridges. The differences in depositional profiles, sediment dynamics and features, as well as acoustic facies between the coral ridges and the juxtaposed dunes show that the coral ridges are entirely bioconstructional and not a veneer of corals covering paleo-sand dunes. This field of biogenic ridges at the Miami Terrace and the distribution of sand streaks as well as active sand dunes provide new insights how the lateral variability of current velocities and sediment transport conditions control the morphology, distribution and genesis of cold-water coral features.
► This study documents cold-water coral ridges at the base of the Miami Terrace. ► Coral ridges are oriented perpendicular to a southward bottom current up to 0.6m/s. ► Coral ridges are biogenic in origin and unrelated to the antecedent topography. ► Active bedload sand transport limits coral ridge development. ► Ridge initiation is related to a Mid-Miocene unconformity.
PREMISE OF THE STUDY:
Areas lacking dominant plants, or gaps, can support high diversity and specialist species. Previous chronosequence research in Florida rosemary scrub showed indistinct gap area ...patterns with fire and the dependence of certain species on gaps. We hypothesized that fire and gap size would affect extinction, colonization, diversity, and vegetation composition.
METHODS:
In 2011–12, we revisited gaps first sampled in 2003, recording vascular plant and ground lichen occurrence by species, gap area, and burn history. We analyzed gap, vegetation, and species dynamics using linear mixed models, with Florida rosemary scrub patch as a random factor.
KEY RESULTS:
Gap areas declined quickly during the first 10 yr postfire and then stabilized. Between 2003 and 2011–12, unburned gaps usually remained extant or split, whereas burned gaps usually merged. Unburned gaps tended to shrink, whereas burned gaps became larger. Species richness was positively related to gap area, fire, and their interaction. Over time, richness declined in unburned gaps and increased in burned gaps. Local extinction and colonization of individual species were related to fire between 2003 and 2011–12. In burned gaps, ground lichens disappeared, but many herbaceous species, including those killed by fire, increased occupancy. Colonization of most species was favored by burning, large gaps, or both.
CONCLUSIONS:
In Florida rosemary scrub, fire and increasing gap size increased species richness and many individual species occurrences, reduced local extinctions, and increased colonizations. Therefore, land management activities that encourage the creation and maintenance of large gaps will promote biodiversity in this system.
Everglades virus (EVEV), subtype II within the Venezuelan equine encephalitis (VEE) virus complex, is a mosquitoborne zoonotic pathogen endemic to south Florida, USA. EVEV infection in humans is ...considered rare, probably because of the sylvatic nature of the vector, the Culex (Melanoconion) cedecei mosquito. The introduction of Cx. panocossa, a tropical vector mosquito of VEE virus subtypes that inhabits urban areas, may increase human EVEV exposure. Field studies investigating spatial and temporal patterns of abundance, host use, and EVEV infection of Cx. cedecei mosquitoes in Everglades National Park found that vector abundance was dynamic across season and region. Rodents, particularly Sigmodon hispidus rats, were primary vertebrate hosts, constituting 77%-100% of Cx. cedecei blood meals. Humans were fed upon at several locations. We detected EVEV infection in Cx. cedecei mosquitoes in lower and upper regions of Everglades National Park only during the wet season, despite an abundance of Cx. cedecei mosquitoes at other sampling times.
This study aims to evaluate the individual and synergistic controls of climatic and land cover changes on stormwater runoff regimes, and perform a comparative synthesis of the historical and future ...runoffs for complex coastal-urban environments. A large-scale (7117 km2) mechanistic hydrologic model was developed for Florida Southeast Coasts Basin as the study area using U.S. Environmental Protection Agency (EPA)'s Storm Water Management Model 5.1. The model was calibrated and validated with daily streamflow observations (Nash-Sutcliffe Efficiency = 0.74 to 0.92) during 2004–2013 (termed 2010s), computing the corresponding runoff volume as a historical reference. Runoffs for 2050s (2044–2053) and 2080s (2076–2085) were quantified by incorporating climatic projections from 20 General Circulation Models and land cover projections from EPA under the Representative Concentration Pathways (RCP) 4.5 and 8.5 scenarios. We found a predominant climatic control on the potential runoff changes and a high vulnerability in the coastal-urban environments. The concurrent changes in climate and land cover led to synergistic (stronger than the sum of individual effects) nonlinear responses of runoff. The projected changes in climate and land cover together would increase the annual basin runoff volume by 118%, 106%, 86%, and 80% under the 2080s-RCP 4.5, 2050s-RCP 4.5, 2050s-RCP 8.5, and 2080s-RCP 8.5 scenarios, respectively. Greater increases in runoff were noted at and around the urban centers than that at the non-urban areas across the basin. The relative increases in runoff were higher during the dry season and transitional months (October–May) than the wet season (June–September). Our findings would guide stormwater management and ecosystem protection for southeast Florida and coastal built environments across the world.
Display omitted
•A large-scale stormwater model was developed with EPA SWMM for southeast Florida.•The coastal-urban environments had a predominant climatic control on runoff changes.•Concurrent climatic and land cover changes led to synergistic changes in runoff.•High increases (80–118%) in coastal-urban runoff were projected by 2050s and 2080s.•Higher increases in runoff and flooding risk were noted in the urban centers.
► Microwave remote sensing provides an opportunity to measure changes in water stage. ► A linear model is developed to relate water stage variation to TRMMPR backscatter. ► Modeled values are ...compared with observed water stage values in South Florida. ► The model works reasonably well in the regions with tree heights greater than 5
m. ► The research presents a novel use of TRMMPR data.
Information on water stage over an extended area is important for hydrological and ecological studies. Microwave remote sensing provides an opportunity to measure changes in water stage from space because of its sensitivity to land surface characteristics; it reduces the need to monitor water stage at multiple locations. In this research, a linear model is developed which relates variation in water stage measurements (
w
s
) to Tropical Rainfall Measuring Mission Precipitation Radar backscatter (
σ°). The estimated water stage from the model is compared with the observed water stage in the wetlands of South Florida. The model performance is assessed by comparing the correlation coefficient (
R), the root mean square error (RMSE), and the non-exceedance probability of mean absolute error between observed and modeled water stage measurements for various landcovers. The model works reasonably well in the regions with tree heights greater than 5 m. For example, over woodlands
R ranges between 0.59–0.93 and the average RMSE
=
19.8
cm. Similarly, for wooded grassland,
R ranges between 0.54–0.93 and the average RMSE
=
19.8
cm. For other relatively shorter height vegetation landcovers such as grassland (
R
=
0.57–0.85, RMSE
=
20.1
cm) and cropland (
R
=
0.69–0.79, RMSE
=
18.2
cm), the model also performs reasonably well. The research presents a novel use of TRMMPR data and gives an insight into the effect of water level in partially inundated vegetation on radar backscatter.
PDF
