Coral communities of Biscayne Bay, Florida and adjacent offshore areas: diversity, abundance, distribution, and environmental correlates

Abstract

ABSTRACT1. Hardbottom habitats of Biscayne Bay, a shallow lagoon adjacent to the city of Miami, Florida, USA, contain a limited number of coral species that represent a small subset of the species found at nearby offshore hardbottom and reef habitats of the Florida Reef Tract. Although the physical characteristics of this basin make it a marginal environment for coral growth, the presence of dense populations of Siderastrea radians and Porites furcata indicate that these, as well as other corals that are found at lower densities, are able to tolerate extreme and fluctuating conditions. Three factors, temperature, sedimentation, and salinity, appear to limit coral abundance, diversity, and distribution within Biscayne Bay.2. Temperatures exhibit high frequencies of extreme high and low values known to cause coral stress and mortality elsewhere. Similarly, sedimentation rates are very high and sediment resuspension caused by currents, storms and boating activities commonly bury corals under sediment layers. Sediment burial was shown experimentally to influence growth and mortality of S. radians.3. The salinity of Biscayne Bay is influenced by freshwater inputs from canal, sheetflow and groundwater sources that create a near-shore environment with low mean salinity and high salinity fluctuation. Coral communities along this western margin have the lowest coral density and species richness. Chronic exposure to low salinity was shown experimentally to cause a decrease in the growth of S. radians.4. The location of Biscayne Bay, downstream of a large restoration effort planned for the Everglades watershed, highlights the need to understand the relationship between the physical environment and the health of benthic communities. The data presented here provide the type of scientific information needed so that management decisions can take into account the potential impacts of human activities on the health of coral populations that are already near their tolerance limits for temperature, salinity, and sedimentation.

Hydrologic interactions of infaunal polychaetes and intertidal groundwater discharge

“…Previous work has associated groundwater discharge with the distribution of epibenthic macrofauna over 100s of meters (Kohout & Kolipinski 1967), reduction of coral density and species richness (Lirman et al 2003), reduction of seagrass community diversity (Kamermans et al 2002), and a shift in dominant polychaete species over as little as 5 m (Zipperle & Reise 2005). Porewater salinity affects the distribution of harpacticoid copepods along with other environmental factors like sediment size, exposure, water saturation, and oxygen penetration (Moore 1979).…”

Pathologies and mortality rates caused by organic carbon and nutrient stressors in three Caribbean coral species

“…Porites furcata, for example, is abundant in disturbed environments, which experience extreme fluctuations in temperature, sedimentation and salinity that exclude most other coral species (e.g. Biscayne Bay, Florida; Lirman et al 2003).…”

Marine Benthic Habitats and Seabed Suitability Mapping for Potential Ocean Current Energy Siting Offshore Southeast Florida

“…This finding is consistent with the literature on the sedimentation patterns in the near-shore littoral environments impacted by human activities. A study by Lirman et al [44] suggested that the sedimentation rates and specifically those measured near navigational inlets, are an order of magnitude higher than those found elsewhere. Grain size data indicate that the northern section of the study area is predominantly composed of various types of sand substrates whereas the mid-and southern sections have large sections of fine-grained sediments.…”

“…Also, they often occur over hard-bottoms which may become undistinguishable when fine grain sediment is layered over it. For example, Lirman et al [44] reported a chronic exposure of coral colonies in Biscayne Bay, FL, to sediment burial due to the impact of the extensive network of canals, levies and navigational inlets constructed in the study area over the past decades. Due to similarities in grain size [20] gravel and glacial seafloor material are considered identical for the purposes of this analysis.…”