Tuesday, 7 October 2008
George R. Brown Convention Center, Exhibit Hall E
Orlando Diaz1, Samira Daroub1, Timothy Lang1 and Michael G. Waldon2, (1)University of Florida, Everglades Res. & Educ. Center, 3200 E Palm Beach Rd. Univ. of FL, Belle Glade, FL 33430-8003
(2)U.S. Fish and Wildlife Service, 646 Cajundome Blvd, Suite 400, Lafayette, LA 70506
The Loxahatchee National
Wildlife Refuge is one of three conservation areas in South Florida designed to provide water storage and flood control, as
well as habitat for native fish and wildlife populations.� Most of the Everglades,
including the refuge, developed as a rainfall-driven system with surface waters
low in nutrients and inorganic ions.�
There is concern that increases in outflow from Stormwater
Treatment Area 1E (STA-1E) may suspend and transport light organic sediments
and nutrients in the receiving canal that may negatively impact the fragile
ecosystem inside the refuge.� The
objective of this study was to measure the effect of STA-1E outflow on
different P species and other selected water properties in the L40 Canal.� Six water surveys under flow drainage
conditions (16,508 � 163,448 m3 h-1) and three under no
flow conditions were conducted in 2006.�
Total P concentrations from samples collected under flow conditions
averaged 77 �g L-1, compared to 56 �g L-1 during no
flow.� Phosphorus concentrations from
individual surveys showed higher differences in P species concentrations
depending on intensity of drainage flow and timing during the rainy
season.� Contribution of total dissolved
P to total P in the water column ranged from as low as 21% (18 �g L-1)
on samples from a low drainage event early in the rainy season (34,544 m3 h-1)
to as high as 75% (83 �g L-1) in samples from one of the highest
drainage events (163,448 m3 h-1) in 2006.� In contrast, particulate P concentrations
were considerable higher early in the rainy season (79% of total P, 71 �g L-1),
with concentrations considerably decreasing toward the end of the rainy
season.� These results suggest that the
net contribution of particulate P most likely resulted from the remobilization
of biological generated particulate matter accumulated in the canal during the
quiescent dry season.�