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publications > paper > phosphorus budgets in Everglades wetland ecosystems: the effects of hydrology and nutrient enrichment
Phosphorus budgets in Everglades wetland ecosystems: the effects of hydrology and nutrient enrichment
Gregory B. Noe and Daniel L. Childers
G. B. Noe
US Geological Survey, 430 National Center, Reston,
VA 20192, USA
e-mail: gnoe@usgs.gov D. L. Childers
Department of Biology and Southeast Environmental
Research Center, Florida International University,
Miami, FL 33199, USA
Abstract
The Florida Everglades is a naturally
oligotrophic hydroscape that has experienced
large changes in ecosystem structure and function
as the result of increased anthropogenic phosphorus (P) loading and hydrologic changes. We
present whole-ecosystem models of P cycling for
Everglades wetlands with differing hydrology and
P enrichment with the goal of synthesizing existing
information into ecosystem P budgets.
Budgets were developed for deeper water oligotrophic
wet prairie/slough ('Slough'), shallower
water oligotrophic Cladium jamaicense ('Cladium'),
partially enriched C. jamaicense/Typha spp.
mixture ('Cladium/Typha'), and enriched Typha
spp. ('Typha') marshes. The majority of ecosystem
P was stored in the soil in all four ecosystem
types, with the flocculent detrital organic matter (floc) layer at the bottom of the water column
storing the next largest proportion of ecosystem P
pools. However, most P cycling involved ecosystem
components in the water column (periphyton,
floc, and consumers) in deeper water,
oligotrophic Slough marsh. Fluxes of P associated
with macrophytes were more important in the
shallower water, oligotrophic Cladium marsh.
The two oligotrophic ecosystem types had similar
total ecosystem P stocks and cycling rates, and
low rates of P cycling associated with soils.
Phosphorus flux rates cannot be estimated for
ecosystem components residing in the water
column in Cladium/Typha or Typha marshes
due to insufficient data. Enrichment caused a
large increase in the importance of macrophytes
to P cycling in Everglades wetlands. The flux of P
from soil to the water column, via roots to live
aboveground tissues to macrophyte detritus,
increased from 0.03 and 0.2 g P m-2 yr-1 in
oligotrophic Slough and Cladium marsh, respectively,
to 1.1 g P m-2 yr-1 in partially enriched
Cladium/Typha, and 1.6 g P m-2 yr-1 in enriched
Typha marsh. This macrophyte translocation P
flux represents a large source of internal eutrophication
to surface waters in P-enriched areas of
the Everglades.
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| Fig. 1 Phosphorus budgets for Everglades wetland ecosystems: a) oligotrophic wet prairie/slough, b) oligotrophic Cladium jamaicense, c) partially enriched Cladium jamaicense/Typha spp. mixture, and d) enriched Typha spp.
Standing stocks (g P m-2 yr-1)
in individual ecosystem
components are shown in
boxes, and net directional
fluxes (g P m-2 yr-1)
between components are
shown with arrows.
Measured fluxes are
shown with solid black
arrows, fluxes estimated
using data from other
ecosystems or estimated
indirectly are shown with
solid gray arrows, fluxes
estimated by mass balance
are shown with dashed
gray arrows, and fluxes
with insufficient
information are shown
with double gray arrows.
Phosphorus
concentrations in
inflowing and outflowing
surface water are also
shown. AG = aboveground [click on images above for larger versions] |
Related information:
SOFIA Project: Effect of Water Flow on Transport of Solutes, Suspended Particles, and Particle-Associated Nutrients in the Everglades Ridge and Slough Landscape
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