Florida seagrass habitat evaluation: A comparative survey for chemical quality

Abstract

Some anthropogenic contaminants were prevalent in seagrass and their rooted sediments but the biological significance is unknown. AbstractContaminant concentrations were determined for media associated with 13 Florida seagrass beds. Concentrations of 10 trace metals were more commonly detected in surface water, sediment and two seagrass species than PAHs, pesticides and PCBs. Concentrations of copper and arsenic in surface water exceeded Florida aquatic life criteria more frequently than other trace elements. Total organic carbon, mercury, chromium, zinc, total chlordane, total PAHs, total PCBs, DDD and DDE were significantly greater in seagrass-rooted sediments than adjacent non-vegetated sediments. Total DDT, DDD, DDE, total chlordane, arsenic, copper and nickel exceeded proposed sediment quality guidelines at six of 13 grass beds. Pesticides, PAHs, and PCBs were below detection in seagrass tissues. Mercury, cadmium, nickel, lead and silver were detected in 50% or more of the tissues for Thalassia testudinum (turtle grass) and Halodule wrightii (shoal grass). Spatial, interspecific and tissue differences were usually an order of magnitude or less.

Nonnutrient anthropogenic chemicals in seagrass ecosystems: Fate and effects

“…Diuron concentrations, however, were as high as 25 g/L. Concentrations of 25 pesticides were below detection in 13 Florida seagrass beds [45].…”

“…Concentrations (g/L) reported for other seagrass sites include those near Corpus Christi, Texas, USA, which were between 10.2 and 15.0 (zinc), 0.9 and 2.5 (copper), 9.0 and 13.9 (nickel), and 0.4 to 0.6 (cadmium) [44]. Lewis et al [45] reported that arsenic (36.3-70.7 g/L) and copper (13.9-61.1 g/L) were commonly detected over 13 Florida grass beds containing T. testudinum and Halodule wrightii but not cadmium, selenium, and silver. In the same study, 23 polyaromatic hydrocarbon (PAH) compounds and 18 polychlorinated biphenyl (PCB) congeners were below method detection limits (method detection limits range ϭ 4-19 g/L).…”

“…Of these, the environmental fate of mercury has been of more public concern due to human health effects of methylated forms. Total mercury concentrations in rooted sediments have ranged from 6 to 37 ng/g dry weight (mean values) [41] and Ͻ4 to 18 ng/g dry weight (single values) [45], and have been as high as 0.51 g/g wet weight [40].…”

Tropical Seagrass as a Bioindicator of Metal Accumulation

“…Human activities such as coastal land disturbance, motor boating and dredging increases pollutants (Burkholder et al 2007; Lewis et al 2007). One way to measure the degree of pollution is by using seagrass as a bioindicator for metal contamination (Ferrat et al 2003;Prange & Dennison 2000;Schlacher-Hoenlinger & Schlacher 1998).…”

Fish Resources of the Gulf of Mexico

“…Fifty-nine percent of the estuarine areas of the U.S. Gulf of Mexico, which are essential nursery and spawning grounds for many finfish and sharks, assessed from 1997 through 2000, were considered impaired or threatened (USEPA 2004). Coastal wetlands and nearshore seagrass beds are critical nursery and spawning grounds for many finfish and sharks; however, Lewis et al (2007) estimated that 78 square kilometers (km 2 ) (30 miles 2 ) of wetlands were being lost annually and that 20-100 % of the seagrasses have been destroyed in some areas of the Gulf of Mexico. The deterioration and even total loss of these critical habitats may greatly reduce the carrying capacity of the Gulf of Mexico for many fish and shark species that depend on these areas as their critical habitat.…”