Publication Date:
2015-11-19
Description:
Upstream source control and Stormwater Treatment Areas (STAs) have reduced phosphorus (P) loads to Water Conservation Area 2A (WCA-2A), a northern Everglades wetland, by three-quarters since year 2000. Nevertheless, large storages of P remain in enriched peat soils and it is unclear how legacy stores will impact spatial and temporal scales of recovery. We re-measured soil P enrichment along a well-studied eutrophication gradient in WCA-2A and applied a profile modeling approach with uncertainty analysis to assess changes in longitudinal soil P gradients 13-years after load reductions. We then analyzed existing internal water P data, using a novel data screening approach, for evidence of lowest possible water P concentrations independent from inflows. We interpret such water P limits as evidence of the strength of internal loading at a location. Results indicate that soil P enrichment persists in the ∼7.5 km long “impacted” zone, with no significant evidence of net advancement or recession, while a large pool of labile P in the flocculent layer consolidated and diminished. There is indeed evidence, both spatial and temporal, that this extensive zone of enriched soil P continues to elevate lowest achievable water P concentrations. The corresponding gradient of elevated water P limits is both receding and diminishing since load reductions, thus providing further evidence toward recovery. However, results also suggest that these “transitory P limits” due to internal loading are likely to persist for decades above water quality targets. These results advance our understanding of recovery in impacted wetlands and are relevant to Everglades restoration. This article is protected by copyright. All rights reserved.
Print ISSN:
0043-1397
Electronic ISSN:
1944-7973
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
