Comparing Productivity and Biogeochemistry of Native and Transplanted Thalassia testudinum and Halodule beaudettei in Big Lagoon, Florida, USA

Abstract

Seagrasses provide ecosystem services such as nursery habitats, refuge, and biogeochemical cycling. However, because seagrass communities are in decline, restoration efforts have increased. The seagrass restoration and monitoring programs at the Florida Department of Environmental Protection (FDEP) transplanted plugs of salvaged seagrasses from dock and marine construction sites. In this study, we used a 2-yr-old FDEP transplant site at Big Lagoon, Pensacola, FL, to compare primary production, respiration, and nutrient fluxes in mixed seagrass beds of Thalassia testudinum (turtle grass) and Halodule beaudettei (shoal grass) with intact, native beds of these seagrasses. We placed light and dark incubation chambers in native and transplanted seagrass beds on 10 different days during the growing season between May and Oct. to measure fluxes of oxygen, nitrate (NO 3 ), dissolved inorganic phosphate (DIP), and ammonium (NH 4 + ). This study found no significant differences in the fluxes of any of the nutrients measured or in the production or respiration rates of native vs transplanted seagrass beds. The most significant environmental factor influencing net community production was light level. Nutrient fluxes were very low and variable, although there were consistent ammonium uptake and nitrate release early in the growing season. This rapid convergence in seagrass function by the transplanted beds to rates similar to those of native beds was likely the result of several factors, including use of plugs for restoration and planting adjacent to existing, healthy beds.

Seasonal Oxygen Dynamics in a Warm Temperate Estuary: Effects of Hydrologic Variability on Measurements of Primary Production, Respiration, and Net Metabolism

“…Residual gross production rates at the shoal site (Fig 8a) were low in spring, peaked in summer, then declined in late summer and fall. This seasonal progression is similar to seagrass productivity estimates derived from chamber incubations in other subtropical seagrass ecosystems (Stutes et al 2007, Yarbro and Carlson 2008, Hester et al 2016. Residual gross production was also significantly correlated with I avg (r = 0.62, P<0.004), similar to other seagrass ecosystems (e.g., Herzka andDunton 1996, Hester et al 2016).…”

“…In this sense, these results were similar to Ziegler and Benner (1998) in the Laguna Madre (Texas, USA) and to Champenois and Borges (2012) in the Bay of Revellata (Corsica, France). Additionally, the magnitudes of residual rates, averaging 138 mmol O 2 m −2 d −1 and 152 mmol O 2 m −2 d −1 for gross production and respiration, respectively, were similar to benthic rates measured in chambers deployed in seagrass meadows (Murray and Wetzel 1987, Ziegler and Benner 1998, Yarbro and Carlson 2008, Nagel et al 2009, Hester et al 2016. Residual gross production rates at the shoal site (Fig 8a) were low in spring, peaked in summer, then declined in late summer and fall.…”

Viable Putative Vibrio vulnificus and parahaemolyticus in the Pensacola and Perdido Bays: Water Column, Sediments, and Invertebrate Biofilms

“…Waters in this system are generally more turbid than in the PBS as a whole, and major sources of freshwater input include the Perdido River and Elevenmile Creek (Macauley et al, 1995). While Escambia Bay/Pensacola Bay and Perdido Bay are major river-dominated systems with freshwater inflow, Big Lagoon is a mesohaline system connecting the PBS and Perdido Bay, where sediments are more sandy than muddy, light attenuation is generally low, and seagrasses are more abundant than in the Escambia or Perdido Bays (Hester et al, 2016;Murrell et al, 2018). Creeks provide freshwater inputs into the three urban bayous in this study: Bayou Grande, Bayou Texar, and Bayou Chico.…”