Lake Barco NEON / BARC

Lake Barco (BARC) is an aquatic NEON field site located in Putman County, Florida about 20 miles east of Gainesville. It is part of the Ordway Swisher Biological Station (OSBS), a 38.5 km² (9500 acre) property owned and managed by the University of Florida as a biological research center. The lake is clear, with light penetrating through most of its depth. It is 0.13 km² (32 acres) in area, situated in watershed that is 0.81 km² (203 acres). It is classified as a seepage lake dominated by groundwater, acting as a discharge and recharge system to the regional Upper Floridian aquifer. It is encompassed within the NEON Southeast Domain that is bounded by the Atlantic Ocean on the east and the Gulf of Mexico to the west. The Domain features a patchwork of forest, grassland, and wetland communities embedded in a matrix that is increasingly dominated by a fast-growing human population. The Domain hosts five other NEON field sites, including two additional aquatic and three terrestrial sites, located in Florida and Georgia. BARC is colocated with the OSBS terrestrial field site. The Suggs Lake (SUGG) aquatic site is also located within the university's OSBS. [9]

North-central Florida’s climate is humid subtropical. Average annual temperature is 20°C (68°F) and mean annual precipitation is 1320 mm (52 in.), most of which typically falls between June and September. Summers here are generally hot and humid, with average summer highs around 32°C (89°F) and lows averaging around 21°C (70°F). Winters are drier and mild, with highs around 19°C (67°F) and lows near 4°C (40°F). In summer months, afternoon and evening thunderstorms bring most of the rain. Winter rainfall is not as intense as the summer storms. Annual precipitation patterns at the site are highly variable and periods of below average precipitation (drought) are not uncommon. The site is also subject to hurricanes and tropical storms. Both hurricane landfall and severe droughts occur about every 15 years on average, with the latter often leading to severe wildfire conditions. Barco Lake has a mean annual temperature of 20.9° (70°F) and mean annual precipitation of 1308 mm (51.5 in). [7] [12] [13] [16]

Barco Lake is part of the Cypresshead Formation and features geological characteristics typical of the area, with a lake bottom of sand, clay, and mud. The region Lake Barco resides in is defined as Karst terrain, defined as a landform that is produced by the primarily dissolution of rocks. Barco Lake is underlain by the Floridan Aquifer dominated by a limestone and dolomite bedrock. Limestone and dolomite bedrock weather quickly and develop into solution holes which in turn allows a higher ground-water flow rate. [5] [11]

The soils in the nearby OSBS terrestrial site are Entisol-order soils that are uncoated, Typic Quartzipsamments. These soils are primarily well-drained and sandy, but low-lying areas near lakes and swamps can have relatively deep layers of organic soils. [10] [16]

Barco Lake is a nutrient poor, relatively clear lake with an average secchi depth of 5.4 m and chlorophyll content of 1 µg/L. Barco Lake has a mean depth of 4.3 m (14 ft.) and a maximum depth of 5.2 m (17 ft.) and is mostly isothermal (does not stratify). It is classified as acidic with a mean pH of 4.5. It is a deep lake that is connected to ground water. There is no discernable inflow or outflow to Barco Lake, although there is some evidence of water inflow from the northern edge of the lake with a flow pattern to the S and SE; mean inflow/outflow rate of 1.7*104 m³/yr. Fluctuation in the water table is generally between 1 to 1.5 m but can reach up to 3-4 m during storm events. The groundwater input accounts for between 5-14% of the annual hydrologic input. The mean hydraulic residence time of the lake is 3.2 years. The lake is fed from the north and northeast by shallow groundwater, which seeps out towards the west and south. Deeper groundwater also flows below the lake. [8] [9] [10]

The riparian vegetation cover is a combination of evergreen forest and mixed shrub/grassland. Closer to the lake, you can find live oak (Quercus geminata) and slash pine (Pinus elloittii) along with St. Johnswort (Hypericum fasciculatum), a woody shrub forming a ring immediately adjacent to the lake. In the upland areas, vegetation such as longleaf pine (Pinus palustris) with an understory of turkey oak (Quercus laevis) predominate. [9] [13] [14]

Barco Lake is an important breeding area for terrestrial amphibians, which include the threatened gopher frog as well as many unusual or endemic insects. Several mammals and birds such as ducks and sandhill cranes use it as an important watering hole. Aquatic organisms sampled by the NEON program at Barco Lake include Aquatic Microbes (surface water), Macroinvertebrates, and Zooplankton. [15]

Land surveyors that mapped local water features on Ordway attached names of families who lived in those areas in the late 1800s. These families who lived on the property grew subsistence crops, tobacco, oranges, and cotton on their farms. They also ran herds of hogs and some cattle in the sandhills. After the First World War, the lakes at Ordway were primarily used for recreation. The lake properties were then bought by sportsmen for hunting and fishing. [1]

The Ordway Preserve is operated and managed to protect the natural communities within and to provide opportunities for scientific research and educational outreach primarily to users from University of Florida, but also to the greater scientific community. The site is closed to the public in order to protect the integrity of the preserve as well as the ongoing research taking place. Many of the ecosystems at OSBS are pyrogenic, and so most of the management onsite is in the form of controlled burns. Different parts of the site are managed on a variety of burn schedules. In some areas where woody species encroachment is high due to natural fire suppression, management also includes mechanical and chemical methods. Mechanical harvest of groundcover seeds occurs in some areas as part of a cooperative agreement with the St. Johns Water Management Agreement. These activities do not occur within NEON plots. In relation to its lake, the station collects data related to hydrology such as surface water quality, ground water levels and lake levels to monitor environment changes over time. In conjunction with the NEON program, additional research monitoring wells have been installed around Barco and Suggs Lakes. [2] [4] [17]

In 2011, The University of Florida signed a 30-year land use agreement with NEON to utilize the Ordway-Swisher Biological Station as the Southeastern Domain site for NEON's ecological observation network. A network of eight groundwater wells was installed using a rotary auger rig. They were installed at varying positions along the rolling hills and required drilling depths between 40-80 feet below ground surface. The meteorological station is located on land near the aquatics portal. A secondary met station is co-located with the buoy. In addition, a staff gauge and inlet and outlet sensor infrastructure are located in the nearshore areas of the lake. The groundwater wells will transmit data back to either the buoy or the aquatics portal location through either wireless or cellular technologies. The buoy, which has underwater sensors to collect data on water composition and quality and meteorological sensors, was anchored at the deepest part of the lake. The initial site characterization survey took place in May 2014 with observational sampling beginning in October 2014 and transitioning to operations in February 2015. Instrumented sampling transitioned to operations in December 2017, just a few months after officially starting sampling in July 2017. [3] [9]