Abstract

Background Field Collection

Materials and Methods

Preliminary Conclusions

As stages in the Water Conservation Area 3A (WCA-3A; Fig 1,2) decline the L67A

canal rather than the marshes conveys the majority of the flow into the

Everglades National Park (ENP). Canal water is typically of poorer quality than

marsh water because canal water has not benefitted from the marsh filtering

removal quality of nutrients. Low stages are associated with high TP levels at

S333. Canal flows, especially at low stage, have the potential of re-suspending

and remobilizing nutrient-rich sediments that accumulate at the bottom of canals.

These phosphorus-rich sediments can be rapidly transported downstream while

contributing part of their P load to canal waters to finally reach the park (Fig 3).

Another potential contributing factor to high phosphorus levels is varying

environmental conditions such as wet and dry seasons, peat oxidation, weather

events, and wildfires.

Research Question

What are the mechanisms responsible for increases in

TP concentration in Everglades canal waters when

water level declines?

The Objectives of this work are:

1- Determine the sources of the elevated TP at S333

2- Establish the most relevant mechanisms driving TP dynamics at S333

Objectives

Cumulative Sum charts

for TP, plotted along the

DO, Turbidity, pH and

sampling time gradients

highlight the thresholds

(red arrow) where TP

changes from below to

above average

concentration.

Similar relationships

TP:WL occurring region

wide suggest

commonalities among

sites in WCA-3A and

perhaps EAA

- There are clear relationships of TP with WL, DO, Turbidity, pH and sampling time (diel

cycle) with thresholds separating hi from low TP waters.

- Although some increase in TP may be due to changing proportions of contribution from

marsh vs upstream canal, a local source from deposited sediments and floc seems an

interesting alternative.

- Changes in the hydraulic geometry of the canal due to declining WL may stir and erode TP-

rich bottom sediments and floc, increasing TP concentration in the water column.

- We are testing this initial hypothesis by collecting and analyzing waters, sediments and floc

during different WL conditions, and especially during critical stages, when approaching and

when reaching the WL threshold

Acknowledgements

This study is part of the NPS funded project “Mechanisms and Conditions Responsible for Elevated TP Levels in Surface

Water Discharges to Shark River Slough within Everglades National Park”, and the NSF funded “Florida Coastal

Everglades Long=Term Ecological Research Project”

ReferencesJaya Das, Samira H. Daroub, Jehangir H. Bhadha, Timothy A. Lang and Manohardeep Josan. 2012. Phosphorus Release and Equilibrium

Dynamics of Canal Sediments within the Everglades Agricultural Area, Florida. Water Air Soil Pollution 223:2865–2879

Katsaounos, Ch., D. L. Giokas, I. D. Leonardos, M.I. Karayannis. 2007. Speciation of phosphorus fractionation in river sediments by

explanatory data analysis. Water Research, 41:406-418

Pisani, O., L.J. Scinto, J.W. Munyon, R. Jaffe. 2015. The respiration of flocculent detrital organic matter (floc) is driven by phosphorus

limitation and substrate quality in a subtropical wetland. Geoderma (241-242) 272-278

Reddy, K. R. , Newman, S. , Osborne, T. Z. , White, J. R. and Fitz, H. C.(2011) 'Phosphorous Cycling in the Greater Everglades Ecosystem:

Legacy Phosphorous Implications for Management and Restoration', Critical Reviews in Environmental Science and Technology, 41:

6, 149 — 186

• Profile measurements (YSI cast): Temp, DO, depth, Cond, Sal, pH, Turbidity

• Surface and bottom waters sampling

• Bottom sediment and floc sampling

• Canal water flow profiles

• Water samples are analyzed for ammonium (NH4+), nitrate+nitrite (N+N), nitrite (NO2-),

total nitrogen (TN), soluble reactive phosphorus (SRP), total phosphorus (TP), total

organic carbon (TOC), silicate (SiO2), chlorophyll a (CHLA), and turbidity using standard

laboratory methods.

• Floc and bottom Sediments collected by pumping and dredging respectively are

subjected to fractionation in i) 30ml deionized water (plant available and water

extractable P; TP-H2O), (ii) 0.5M NaHCO3 (pH ¼ 8.2) (weakly sorbed-bioavailable

organic and inorganic P; TP-HCO3), (iii) 0.1M NaOH (strongly bound chemisorbed P-

potentially bioavailable; TP-NaOH) and (iv) 1M HCl (apatite or Ca-bound P non

bioavailable;TP-HCl)

Total Phosphorous Levels in Surface Water Discharges to Shark River Slough,

Everglades National Park

Joffre Castro1 Henry Briceño2, Piero Gardinali21 National Park Service, Everglades National Park

2Southeast Environmental Research Center

Florida International University, Miami, FL

Monitoring and current studies have identified a strong correlation between

Total Phosphorous (TP) at structure S333 (inflow structure to ENP) and canal

stage. Waters from upstream S333 (along the L67A and L29 canal) are mostly

the results of managed deliveries by the SFWMD and the exchange with

freshwater marshes and groundwater. The conditions and mechanisms that

cause elevated TP are unknown. Some may result from changes in natural

conditions but others may be the direct result of anthropogenic actions. Water

levels in Everglades marshes and canals are closely tied to management and

climate variability. The purpose of this study is to identify the sources of the

elevated TP at S333 and, if possible, characterize them as to be from either

local effects and conditions at S333 or upstream of S333 within the L67A

Canal, L29 Canal or the WCA-3A marsh.

SOURCE:

c= canal

m= marsh

u= upstream

g= ground

s=sediment

CONCEPTUAL MODEL

L29

S152

S333

WC3A

ENP

S12D

Study Area

COMPONENT:

W= water

S= Sediment

Preliminary Results

• Exploration of existing datasets (SFWMD, EDEN, USGS) confirms significant

correlations between TP concentrations and WL, pH, Turbidity, Dissolved oxygen and

even sampling time of the day (Fig 4 to XX)

0

0.005

0.01

0.015

0.02

0.025

0.03

6 6.5 7 7.5 8 8.5 9 9.5

mg

/L T

P

S333 H stage (ft)

S333 Stage linked to S333 TP Regime shifts S333 TP Weighed mean TP

Regime Shift Analysis

• We confirmed the inverse WL:TP relationship for stations connected to WCA3-A

(S151, S152, S12D, S344 and even S150 located in the Everglades Agricultural Area

(EAA) . In all of them there is a significant WL threshold (system shift) separating

above from below average TP (Fig 5, 6). Main thresholds are between 7 and 8 ft WL.

-5

0

5

10

15

20

25

30

35

5 6 7 8 9 10

TP

Cu

sum

S333 WL (ft)

S333 TP cusum

Below average TPAbove average TP

-2

0

2

4

6

8

10

12

6 7 8 9 10 11 12

TP c

usu

m

Water Level S150 T

TP cusum

Above average TP

Below average TP

-2

0

2

4

6

8

10

12

14

16

6.5 7.5 8.5 9.5 10.5

Cu

sum

WL (ft)

S152 (DPM) TP cusum

Above average TP Below average TP

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

0 5 10 15 20

TP C

usum

Turbidity

TP S333

1.5 ft

-20

-15

-10

-5

0

5

0 5 10 15 20 25

TP C

usu

m

Turbidity (NTU)

TP S333

3.1 NTU

-14.0

-12.0

-10.0

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.00 6.50 7.00 7.50 8.00 8.50

TP C

usu

m

pH

TP S333

7.58

-10

0

10

20

30

40

50

60

70

0 4 8 12 16

TP C

usu

m

Dissolved Oxygen (mg/l)

TP S3333.4 mg/l

S150

S151

S333S12D

S344

S152

0

1

2

3

4

5

6

7

8

9

10

6 6.5 7 7.5 8 8.5 9 9.5 10 10.5

TP c

usu

m (

SD)

WL S151 H (ft)

TP cusum

Above average TP Below average TP

-4

-202468

10121416

7 7.5 8 8.5 9 9.5 10

Cu

sum

WL S12D

TP S12DA cusum

-50

-40

-30

-20

-10

0

10

7:12 9:36 12:00 14:24 16:48

TP c

usu

m

Day time

TP S333

11:25

Wc

Wm

Ws

WgWc

WcWc Wm

Wc

Wg

Wu

Sm

ScSc Sm

Sc

Su

Sb