Upload
rusti
View
22
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Evaluating the Influence that Anthropogenic Inputs have on Carbon and Nitrogen Cycling and on the Biological Assemblages in Tampa Bay, FL David Hollander, Elon Malkin, Ed Van Vleet College of Marine Science, St. Petersburg, FL 33701 in collaboration with - PowerPoint PPT Presentation
Citation preview
Evaluating the Influence that Anthropogenic Inputs have on Carbon and Nitrogen Cycling and on the Biological
Assemblages in Tampa Bay, FL
David Hollander, Elon Malkin, Ed Van VleetCollege of Marine Science, St. Petersburg, FL 33701
in collaboration withT. Edgar, T Cronin, P. Swarzenski, K. Yates, USGS Program Leaders
Project Objectives: Determine how historical human influences have:
• Altered the geochemical cycling of carbon and nitrogen (today’s presentation)
• Modified ecosystem structure as recorded in the inputs of sedimentary organic matter.
Research StrategyField studies:
•Sediment coring throughout Tampa BayAnalytical approach:
•Organic carbon and nitrogen concentrations– reflects increasing input & production of organic matter– C:N Ratios determine algal vs terrestrial inputs
•Stable Isotopes of organic carbon and nitrogen– reflects specific nutrient inputs and assimilation– trophic relationships
•Molecular organic geochemical analysis– reflects organic inputs (algal, bacterial, terrestrial and pollution)
Historical Land-use characterization:•USGS mapping group •Southwest Water management District
Linking the Sedimentary Geochemical Record in Tampa Bay to Historical Changes in
Land Use Development and Nutrient Inputs
Watershed’s land useUrban / Industrial, Agricultural, Natural
Recorded in Tampa Bay’s Sediments:TOC, TON, C/N,
15N, Molecular Biomarkers
Changing nutrient inputs:•Sources-15N specific•concentrations•bioavailability
Safety Harbor/Feather Sound
Hillsborough Bay/Alafia River
Terra Ceia/Aquatic Preseerve
Study Sites:•Sediment Cores•Geochemical Studies
•Area of land-use characterization
Tampa Bay •6 Watersheds •Variable land-use
Historical Land-Use Changes
• Alafia: increasing urbanization/industrialization • Terra Ceia: increasing agriculture, recent urban • Feather Sound: increasing residential urbanization
15N
, o/o
o A
ir
Fertilizer
Land Plants
Soil
Urban-Sewage Industrial
Specific Nutrient Input
Nitrogen Isotope Fingerprinting of Nutrient Inputs
Safety Harbor-Residential
Terra Ceia-Agriculture
Hillsborough-Urban
Linking Sedimentary & Land-Use Records:
•TON/TOC- 4x increase due to nutrient input and increased production•Transition from vascular plant to algal/bacterial inputs (C:N, biomarkers)•Enriched 15N > 10 ‰, coprastanol reflect wastewater-industrial inputs
1952 1995
TOC, Wt% C/N, Atomic Ratio 15N, ‰ Air
Dep
th (
cm)
Algal Terr Plants Soil Urban
TON, Wt%Fertilizer/Ter Plant
Redeposited layer
Hillsborough Bay/Alafia River Urbanization/Industrialization
Hum
anIm
pact
Linking Sedimentary and Land-Use Records1952
•Increasing nutrient inputs leading to production (TOC/TON)•Transition from vascular plant to algal/bacterial inputs (C:N, biomarkers)•15N- Agricultural nutrient mimic vascular plant inputs, recent urban
1995D
epth
(cm
)
Agricult/TerPlant
TOC, Wt% C/N, Atomic Ratio 15N, ‰ Air
TON, Wt%
Terra Ceia/Aquatic PreserveAgricultural
Recent urbanization
Soil
Urban
UrbanFertilizer/Terr Plants
Algal Terr Plants
Hum
anIm
pact
Alafi
a
Linking Sedimentary and Land-Use Records
1952 1995
•Delayed geochemical response reflects later land use development•Abrupt transition to algal/ bacterial inputs•15N reflects increasing residential inputs
(commercial fertilizer, septic-wastewater)
Dep
th (
cm)
TOC, Wt% C/N, Atomic Ratio 15N, ‰ Air
TON, Wt%
Safety Harbor/Feather Sound: Residential Urbanization
Redeposited layer
Hum
anIm
pact
Alafi
a
Terr
a Ce
ia
Algal Terr Plants Soil UrbanFertilizer/Terr Plants
Geochemical Implications for Ecosystem Modes
• Enables “hind-forecasting” of regional Bay productivity
• Linking biological responses recorded in sediments to historical land use and nutrient inputs
• Allows model refinement of nutrient forcing functions • Distinguishing nutrient abundance from
bioavailability• Allows for predictive food-web behavior
• Defines relationships among nutrient inputs, primary productivity, and the abundance of economically important upper trophic level consumers