Nitrogen Sources and Fluxes to Indian River Lagoon Ecosystem
Alisa Britt Kepple
GIS in Water Resources
CE 394K.3
Fall 2002
St. Lucie Inlet: South Eastern Florida Last stop on the Intercoastal Waterway
1. Water Quality Sample Collection and Stream Networks:
Arc Map Layers
• Ideal sample collection sites will be chosen after completion of base map and query analysis – (base map to show idealized collection sites within proximity of most highly populated, commercialized and farmed areas and areas exhibiting highest nutrient concentrations).
• Interactive query and trace function analysis to determine most likely point source of highest nutrient concentrations along the stream network
Why Should We Care About DIN and PON Concentrations Leaving the St. Lucie Inlet?
* The National Academy of Sciences has proposed that the eutrophication caused by accelerated nitrogen inputs is the biggest threat to coastal resources in the world.
The Indian River lagoon provides an opportunity to study the direct
effects of agricultural rich - population growth on a regional estuary.
Questions to be answered with this study:
• What is the major source of anthropogenically introduced nitrogen to this system?– Fertilizer– Manure– Boat Pump out Positive source identification of nutrients to the lagoon using Arc
Hydro GIS stream tracing and multi-stable isotope tracers for positive source identification
The problem at St. Lucie:Storm Water Run-off
disrupts the natural ecosytem
• Due to increased population, deforestation, agriculture and industrialization periods of heavy rain lead to:– Influx of nutrients
• Sustained algal blooms– Reduced dissolved oxygen concentrations- Fish Kills
– Obstruct Sunlight - Sea Grass Beds destroyed
– Erosion- Influx of Fine Grained Sediment– Sea Grass Beds and benthic fauna populations destroyed
Part One: Nitrogen Sources to the lagoon
The riverine flux increases in direct proportion to
• Anthropogenic Sources– Fertilizer
– Atmospheric pollution
– Nitrogen fixation by crops
– import/ export of food and feedstocks
– Sewage effluent
– Riverine input of introduced vegetation
• Natural Sources– In-situ N fixation (absent from most estuaries)
– Riverine input of indigenous vegetation
14 N2
Trying to identify the SOURCE of nutrient pollution is a problem:
Euphotic Zone
Atmosphere
NO3-
15PON15 DON 15 NH4
+
N2O
15NO2-
Phytoplankton uptake and assimilation of the N-15 enriched nitrate
N-15 enriched PON incorporated in the sediment record
Sediment
PON (original signal)
Mineralization
NO3-
The Determination and Relation Between Nitrate Concentrations in Rivers and the
Marine Environment
• How much nitrate or PON was introduced from a particular source is complicated by:
– The occurrence of multiple possible sources of nitrate and PON
– Overlapping N isotopic composition between point and non-point sources
– Co-existence of biogeochemical processes that alter the stable isotopic signature and concentrations of nitrate which is then incorporated into PON
However, By Running an Additional Isotope on NO3-
Multi-isotope studies offer a direct means of source identification because different sources of nitrate and PON have isotopically distinct C, N, O signatures
HUC 03
Indian River Lagoon Counties
Hydrologic Units
3080101
3080102
3080103
3080201
3080202
3080203
Watershed Counties and Rivers
POLK
LAKE
LEVY
CLAY
PASCO
DIXIE
DIXIE
UNION
BAKER
DUVAL
MARTIN
HARDEE
ORANGESUMTER
CITRUS
MARION
PUTNAM
TAYLOR
ECHOLS
NASSAUBROOKS
CLINCH
MANATEE
OSCEOLA
BREVARD
VOLUSIA
FLAGLER
ALACHUA
MADISON
LOWNDES
ST LUCIE
PINELLAS
HERNANDO
SEMINOLE
BRADFORD
SUWANNEE ST JOHNS
HAMILTON
COLUMBIA
HIGHLANDS
GILCHRIST
LAFAYETTE
OKEECHOBEE
INDIAN RIVERHILLSBOROUGH
Estimated Nitrogenous Fertilizer Application per County in 2001
-99
4.323785
0.961725
1.480908
1.114747
2.319292
0.734493
5.138920
3.080350
0.091683
1.469558 1.004775
0.992883
0.205902
0.746293
2.6192463.670489
1.288561
0.046296
2.287683
0.992820
0.403742
5.876928
0.218687
0.205956
0.374617
8.033311
3.474556
1.463605
9.709559
0.818216
1.232861
1.419924
3.474248
0.501187
9.656767
1.329375
0.059839
0.0906470.116352
1.923630
1.654812
0.531716
0.273427
0.444816
1.166625
5.282602
0.992883
0.037766
0.992883
1.809702
5.493150
3.474556
3.061913
0.205956
0.205902
1.114747
9.656765
1.114747
3.474555
1.329376
5.282601
9.709562
0.205902
9.709558
0.992883
0.205902
5.2826018.033311
0.218687
0.037766
0.273427
0.273427
0.205956
0.273427
0.218687
3.474555
0.992883
1.288561
0.734493
0.273427
5.138921
0.734493
0.273427
0.218687
1.114747
0.501187
0.734493
8.033312
0.734493
0.734493
5.138920
0.046296
0.091683
Farms and Cattle Distribution in 2000
Water Discharge Permits and Real time Stream flow Monitoring
Stations
Proposed Sampling Sites
POLK
LAKE
LEVY
CLAY
PASCO
DIXIE
DIXIE
UNION
BAKER
DUVAL
MARTIN
HARDEE
ORANGESUMTER
CITRUS
MARION
PUTNAM
TAYLOR
ECHOLS
NASSAUBROOKS
CLINCH
MANATEE
OSCEOLA
BREVARD
VOLUSIA
FLAGLER
ALACHUA
MADISON
LOWNDES
ST LUCIE
PINELLAS
HERNANDO
SEMINOLE
BRADFORD
SUWANNEE ST JOHNS
HAMILTON
COLUMBIA
HIGHLANDS
GILCHRIST
LAFAYETTE
OKEECHOBEE
INDIAN RIVERHILLSBOROUGH
Federally Endangered SpeciesAmerican AlligatorAtlantic Hawksbill TurtleAtlantic Green Sea TurtleEastern Indigo SnakeLeatherback Sea TurtleLoggerhead Sea TurtleShort Nosed SturgeonWest India ManateeSoutheastern Beach MouseBachman’s WarblerBald EagleFlorida Scrub JayKirtland’s WarblerPeregrine FalconPiping PloverRed WoodpeckerRoseate TernSnail KiteWood Stork