Geology topics

Research about South Florida

Source-linked reports with geographic coverage including South Florida.

9 recordsLinked to original sources

USGS2020

Aligning climate models with stakeholder needs: Advances in communicating future rainfall uncertainties for south Florida decision makers

Changes in future precipitation are of great importance to climate data users in South Florida. A recent U.S. Geological Survey workshop, “Increasing Confidence in Precipitation Projections for Everglades Restoration,” highlighted a gap between standard climate model outputs and the climate information needs of some key Florida natural resource managers. These natural resource managers (hereafter broadly defined as “climate data users”) need more tailored output than is commonly provided by the climate modeling community. This study responds to these user needs by outlining and testing an adaptable methodology to select output from ensemble climate‐model simulations based on user‐defined precipitation drivers, using statistical methods common across scientific disciplines. This methodology is developed to provide a “decision matrix” that guides climate data users to specify the subset of models most important to their work based on each user's season (winter, summer, and annual) and the condition (dry, wet, neutral, and no threshold events) of interest. The decision matrix is intended to better communicate the subset of models best representing precipitation drivers. This information could increase users' confidence in climate models as a resource for natural resource planning and can be used to direct future dynamical downscaling efforts. This methodology is based in dynamical processes controlling precipitation via remote and local teleconnections. We also suggest that future climate studies in South Florida include high‐resolution climate model runs (i.e., ocean eddy resolving) in conjunction with dynamical downscaling to adequately capture precipitation variability.

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USGS2019

Assessment of uncertainty in multi-model means of downscaled south Florida precipitation for projected (2019-2099) climate

South Florida resource management, particularly the Everglades restoration effort, is beginning to consider projections of precipitation from multiple climate models for decision-making. Because precipitation changes can significantly affect the Everglades ecosystem, characterization of precipitation projection uncertainty is important for resource management decisions, and reduction of uncertainty is desired for better decision-making. Though uncertainty of precipitation projections has been characterized for many regions, uncertainty has not been sufficiently quantified for south Florida. This study builds upon prior results for projected Florida precipitation by adding recent climate model simulations, seasonal and spatial information, and uncertainty quantification and reduction. We identify the multi-model mean change in south Florida precipitation and characterize the uncertainty of 37 statistically downscaled Coupled Model Intercomparison Project Phase 5 models. For 2019−45, there is a likely (over 60% of ensemble members) increase in south Florida annual mean precipitation owing to a likely to very likely (near 90% of ensemble members) increase in dry season (November, December, January) precipitation, while wet season (June, July, August) shows a more likely than not (over 50% of ensemble members) decrease in precipitation in southern region and increase in precipitation in northern region. As south Florida agencies are on the verge of including precipitation projections in their upcoming planning horizon, this information will aid south Florida practitioners in decisions influenced by future rainfall.

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USGS2011

Spatial pattern formation of coastal vegetation in response to external gradients and positive feedbacks affecting soil porewater salinity: A model study

Coastal vegetation of South Florida typically comprises salinity-tolerant mangroves bordering salinity-intolerant hardwood hammocks and fresh water marshes. Two primary ecological factors appear to influence the maintenance of mangrove/hammock ecotones against changes that might occur due to disturbances. One of these is a gradient in one or more environmental factors. The other is the action of positive feedback mechanisms, in which each vegetation community influences its local environment to favor itself, reinforcing the boundary between communities. The relative contributions of these two factors, however, can be hard to discern. A spatially explicit individual-based model of vegetation, coupled with a model of soil hydrology and salinity dynamics is presented here to simulate mangrove/hammock ecotones in the coastal margin habitats of South Florida. The model simulation results indicate that an environmental gradient of salinity, caused by tidal flux, is the key factor separating vegetation communities, while positive feedback involving the different interaction of each vegetation type with the vadose zone salinity increases the sharpness of boundaries, and maintains the ecological resilience of mangrove/hammock ecotones against small disturbances. Investigation of effects of precipitation on positive feedback indicates that the dry season, with its low precipitation, is the period of strongest positive feedback.

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USGS2010

Factors influencing reproductive performance of northern bobwhite in South Florida

Reproductive success is a critical component of individual fitness, and also an important determinant of growth rates of populations characterized by early maturity and high fecundity. We used radiotelemetry data collected during 2003–2008 to estimate reproductive parameters in a declining northern bobwhite ( Colinus virginianus ) population in South Florida, and to test hypotheses regarding factors influencing these parameters. The overall clutch size was 12.10 ± 0.22, but females laid more eggs in their first clutch (12.43 ± 0.24) than in subsequent clutches (10.19 ± 0.53) within a nesting season. Daily nest survival was higher for first (0.966 ± 0.003) than subsequent nests (0.936 ± 0.011). Hatchability (proportion of laid eggs that hatched conditional upon nest survival to hatching) was 0.853 ± 0.008, but was higher for nests incubated by females (0.873 ± 0.009) than those incubated by males (0.798 ± 0.018). The proportion of individuals attempting a second nest was 0.112 ± 0.024 and 0.281 ± 0.040 when the first nest was successful and failed, respectively. Hatchability was lower when the nesting habitat was burned the previous winter. We found no evidence that food strip density (a management practice to provide supplemental food) influenced any of the reproductive parameters. Mean summer temperature affected hatchability, nest survival, and proportion of nests incubated by males. Overall, the reproductive output in our study population was lower than that reported for most other bobwhite populations, indicating that low reproductive performance may have contributed to bobwhite population declines in our study site. These results suggest that current management practices, particularly those related to habitat and harvest management, need careful evaluation.

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USGS2010

Salinity tolerance of the African Jewelfish Hemichromis letourneuxi , a non-native cichlid in South Florida (USA)

The African Jewelfish (Cichlidae: Hemichromis letourneuxi ) is a predatory, non-native fish that has recently (since 2000) begun to expand its geographic range across south Florida. The salinity tolerance of H. letourneuxi was unknown, and thus it was unclear whether the species could use estuarine or coastal environments. The response of H. letourneuxi to chronic change in salinity was evaluated here by exposing fish to progressively increasing salinities (0–80 ppt). Fish were held at target salinities for a minimum of 30 days. The species showed excellent survival from 0–50 ppt. At 60 ppt, only 25% of the fish survived, and mean estimated survival time was 12 days. Above 60 ppt, mortality was 100%. Fish grew equally well from 0–50 ppt. In another experiment, fish were transferred directly from freshwater to various salinities from 5–35 ppt (seawater) and held for seven days, after which survivors were returned to freshwater. All fish transferred directly from freshwater to salinities up to 20 ppt survived; only 56% survived when transferred from freshwater to 25 ppt, and none survived transfer above 25 ppt. Experimental results indicated that H. letourneuxi can persist easily in salinities prevalent in coastal environments, even during periods of hypersalinity common in south Florida estuaries. Salinity will not restrict its dispersal by coastal pathways.

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USGS2010

Epizootic ulcerative syndrome caused by Aphanomyces invadans in captive bullseye snakehead Channa marulius collected from south Florida, USA

Epizootic ulcerative syndrome (EUS) caused by the oomycete Aphanomyces invadans is an invasive, opportunistic disease of both freshwater and estuarine fishes. Originally documented as the cause of mycotic granulomatosis of ornamental fishes in Japan and as the cause of EUS of fishes in southeast Asia and Australia, this pathogen is also present in estuaries and freshwater bodies of the Atlantic and gulf coasts of the USA. We describe a mass mortality event of 343 captive juvenile bullseye snakehead Channa marulius collected from freshwater canals in Miami-Dade County, Florida. Clinical signs appeared within the first 2 d of captivity and included petechiae, ulceration, erratic swimming, and inappetence. Histological examination revealed hyphae invading from the skin lesions deep into the musculature and internal organs. Species identification was confirmed using a species-specific PCR assay. Despite therapeutic attempts, 100% mortality occurred. This represents the first documented case of EUS in bullseye snakehead fish collected from waters in the USA. Future investigation of the distribution and prevalence of A. invadans within the bullseye snakehead range in south Florida may give insight into this pathogen-host system.

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USGS1993

Water Resources Data, Florida, Water Year 1992. Volume 2B. South Florida Ground Water

This volume of the annual hydrologic data report of Florida is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by State, local, and Federal agencies, and the private sector for developing and managing our Nation's land and water resources. Hydrologic data for Florida are contained in four volumes.

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USGS1990

Water resources data, Florida, water year 1989. Volume 2A. South Florida surface water

Water resources data for the 1989 water year in Florida consists of continuous or daily discharge for 295 streams, periodic discharge for 36 streams, miscellaneous discharge for 75 streams, continuous or daily stage for 154 streams, periodic stage for 13 streams, peak discharge for 57 streams, continuous daily tide stage for 12 streams, and peak stage for 30 streams, continuous or daily elevations for 72 lakes, periodic elevations for 72 lakes; continuous ground-water levels for 514 wells, periodic groundwater levels for 514 wells, and miscellaneous water level measurements for 2,678 wells; quality of water data for 149 surface water sites and 827 wells. The data for South Florida include continuous or daily discharge for 61 streams, continuous or daily stage for 80 streams, continuous elevation for 1 lake; continuous ground-water levels for 220 wells, periodic ground-water levels for 320 wells, and miscellaneous water-level measurements for 329 wells; quality-of-water for 3 surface water sites and 545 wells. This data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation local, state and federal agencies in Florida.

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USGS1986

Water resources data, Florida, water year 1984. Volume 2B. South Florida ground water

Water resources data for the 1984 water year in Florida consists of continuous or daily discharge for 251 streams, periodic discharge for 32 streams, miscellaneous discharge for 43 stream, continuous or daily stage for 92 streams, periodic stage for 31 streams, peak discharge for 60 streams, and peak stage for 37 streams; continuous or daily elevations for 73 lakes, periodic elevations for 82 lakes; continuous ground water levels for 467 wells, and periodic ground water levels for 539 wells; and miscellaneous water level measurement for 2,039 wells; quality of water data for 200 surface water sites and 596 wells. The data for south Florida includes continuous or daily discharge for 74 streams, periodic discharge for 2 streams, peak discharge for 2 streams, continuous or daily stage for 76 streams, and periodic stage for 29 streams; continuous elevation for 18 lakes and periodic elevations for 5 lakes; continuous ground water levels for 180 wells, periodic ground water levels for 130 wells, and miscellaneous water level measurements for 360 wells; quality of water for 40 surface water sites and for 310 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

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