Transcript Dr. Jim Sickman - Soil and Water Science

Resolving sources of dissolved organic matter in
the Sacramento-San Joaquin Delta by
radiocarbon dating
James O. Sickman
Soil and Water Science Department, University of Florida
Carol DiGiorgio
California Department of Water Resources
M. Lee Davisson
Lawrence Livermore National Laboratory
Delores Lucero
University of Florida
Erin Waites
Department of Water Resources
Presented at:
October 2004 CALFED Science Conference
Who am I?
I am an interdisciplinary scientist
working in and across the fields of
biogeochemistry, limnology and
watershed science
Watersheds
My research program is focused on
biogeochemical cycling of C, N and P
in lakes, rivers and wetlands
In these terrestrial and aquatic
ecosystems I utilize standard
watershed analysis along with
application of isotopes ( e.g., d15N and
d18O of nitrate, d13C, D14C of dissolved
organic matter) to solve environmental
problems
Limnology
My Research
Biogeochemistry
Education and Work History
Education:
Ph.D., Ecology, Evolution and Marine Biology (emphasis in biogeochemistry and
limnology) University of California, Santa Barbara, 2001
M.A., Aquatic and Population Biology University of California, Santa Barbara
B.A., Aquatic Biology, University of California, Santa Barbara
Work Experience:
2004 – present: Assistant Professor. Soil and Water Science Department, University
of Florida-IFAS. Biogeochemistry of rivers, lakes and wetlands
2003 – 2004: Assistant Professor. Department of Geology and Geophysics.
University of New Orleans. Watershed biogeochemistry and ecosystem restoration in
the Mississippi Delta and Sacramento River Delta
2001 – 2003: Senior Environmental Scientist - California Department of Water
Resources, Division of Environmental Services, Sacramento, California. Carbon
biogeochemistry, AMS carbon dating, aquatic ecological processes and water-quality
investigations of the Sacramento-San Joaquin River Delta and State Water Project
1983 – 2001: Staff Research Associate IV. Donald Bren School of Environmental
Science and Management, University of California, Santa Barbara. Global-change
research on biogeochemistry, aquatic ecology and hydrology of the Sierra Nevada
and Rocky Mountains.
Current Research: California
C&N Biogeochemistry of
Montane Watersheds
DOM Sources and Fate in
Rivers and Estuaries
Aquatic Ecology of Oligotrophic
Lakes
Effects of Seasonal Transitions on
Biogeochemistry of Chaparral
Current Research: Florida
Causes of macroalgae blooms in
Florida springs (J. Stevenson, A.
Pinowska MSU; R. Reddy UF)
Impacts of Melaleuca
quinquenervia invasion on soil
biogeochemical properties (M.
Martin UF, P. Tipping USDA)
Sources of DOM to St Johns and
Caloosahatchee Rivers (M.
Fisher SJRMD, TJ Evens USDA)
Teaching: Current Courses (1)
Spring 2005: SOS 6456 Advanced Biogeochemistry (3 credits)

TOPIC:
Biogeochemical Cycles and Global Change: Sustaining Biodiversity and
Ecosystem Services in Soils and Sediments

PREREQUISITES:
Graduate standing, BSC 2011 and 2011L (population biology) or equivalent,
AND SOS 3022 (soil chemistry ) or equivalent

COURSE DESCRIPTION:
This course will present an in-depth treatment of global elemental cycles in
the context of Global Change. Topics that will be covered include properties
of and transfers between the key reservoirs of C, N, S & P, coupling of
biogeochemical cycles and climate, and human modification of the Earth
System. Discussion of ecosystem services provided by soils and sediments
in terrestrial and aquatic ecosystems will be emphasized
Teaching: Current Courses (2)
Fall 2005: SOS 4932 Environmental Biogeochemistry (3 credits)

PREREQUISITES:
BSC 2010 and 2010L (general biology) or equivalent, AND CHM 2045 and
2045L (general chemistry) or equivalent

COURSE DESCRIPTION:
This course will examine the biogeochemical systems of the Earth for the
past 5 billion years. We will consider the effects of life on the Earth's
chemistry on a global scale, emphasizing the impact of humans in altering
the global biogeochemical cycles of C, N, S, and P. The course will examine
several important, but complex questions regarding the Earth System: 1)
How did the Earth System operate in the absence of significant human
influence? 2) How can human-driven effects on global biogeochemical
cycles be discerned from those due to natural variability? 3) What are the
implications of changes in the Earth’s biogeochemical systems for human
well-being? 4.) How robust are the Earth’s biogeochemical systems in the
face of anthropogenic forcings? Topics that will be covered include element
cycling, coupled biogeochemical cycles, and solutions for global change
including economic valuation of natural ecosystem functions.
Teaching: Planned Course (3)
John Wesley Powell, renowned explorer of the Grand Canyon defines a watershed as "that area of land, a bounded
hydrologic system, within which all living things are inextricably linked by their common water course and
where, as humans settled, simple logic demanded that they become part of a community”
SOS 4XXX/5XXX: Watershed Science and Analysis
COURSE DESCRIPTION:
Given the interconnectedness of watersheds and the integrating influence of hydrology,
watersheds are a fundamental scale at which to study and manage ecosystems. Watershed
science is an interdisciplinary field that incorporates fundamental and applied knowledge of
natural sciences (hydrology, geomorphology, chemistry, biology, geology) and social sciences
(law, environmental policy and resource economics). This course will provide advanced training in
concepts, tools and methods for solving watershed-scale problems. It will consist of a combination
of lecture, field work and laboratory analyses. A local watershed will be used as the focus of the
course.
Topics to be covered:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Introduction to watershed science
Field/lab methods in watershed analysis
Remote sensing and GIS
Geomorphology
Hydrologic and hydrochemical modeling
Biogeochemistry of watersheds
Use of environmental isotopes in watershed science
Watersheds in environmental policy and regulation
Environmental monitoring, databases and analysis
Isotopes of Carbon and Their Abundance
Isotope Protons Neutrons Proportion
12C
6
6
Half life
99%
stable
13C
6
7
1%
14C
6
8
0.0000000001% 5568 years
Radiocarbon Basics
http://www.rlaha.ox.ac.uk/orau/calibration.html
History of Radiocarbon Dating

Invented by Willard F. Libby of the University of
Chicago after the end of World War 2.

Libby later received the Nobel Prize in
Chemistry in 1960 for the radiocarbon
discovery
Shroud of Turin
(AD 1260-1390)
http://www.c14dating.com/k12.html
Managing water quality and the ecological
health of the Delta affects all of California
Flow in and through the Delta:
Comprises 70% of annual California runoff
Supplies drinking water to 23 million people
Maintains agricultural vitality of California economy
Evolving concerns over past 50 years:
Primary conduit for state water project flows
Expanding role for environmental flows
Increasing degradation of water quality
Principal quality problems related to:
Salinity, agricultural wastes, local land
use, and conflicting flow management
strategies
California’s Delta region exhibits elements common to agricultural/urban
areas of Florida
Restoration of Delta may have unwanted
consequences for water quality
The CALFED Restoration mission is to balance ecological,
agricultural, and urban demands, but
How do we restore habitat, without:
high organic loads leading to carcinogenic by-products formed
during drinking water treatment



carcinogen levels increase proportionally with organic matter content
natural wetlands have 5-10X more organic matter than Delta today
EPA STAGE 1 D/DBP RULE ON THE HORIZON
bioaccumulating toxic metals that impact fish:

wetland chemistry promotes bioavailability of mercury and selenium
Increasing salinity in municipal and agricultural supplies

2-5X increase in bromide renders chlorinated water undrinkable
Promoting land subsidence
Carbon runoff from agricultural practices is a growing concern for
water quality
The Dynamic Delta Landscape Presents Unique Challenges
for Drinking Water Quality
Today
Wetland
Forest
Grasses
Banks
Pumping
Plant
Urban
Historic
Agricultural
CO2
Wetland
DOC
Organic-rich soils
DOM is a precursor to disinfection byproducts in finished drinking water
DOM likely originates from modern and historical sources
Relative proportions of different sources will vary during water year
Determination of Delta Island DOM Influence at Banks
Can Isotopic fingerprinting determine if:
Delta island peat is a significant
source of C loading to the State Water
Project?
C inputs from Delta island peat vary
through time depending on seasonal
and hydrologic conditions?
Simple Conceptual Model for DOM Sources
to the State Water Project
Riverine DOM
Peat-derived DOM
State Water Project
Sampling and Analysis
Monthly sampling:
 Rivers
 Ag drains
Periodic sampling:
 Urban runoff
DOM Fractionation
Measurements:
 AMS carbon dating
 C, N and S isotopes
 SUVA
 THMFP
Water fingerprinting using
DSM2 model
Emphasis to date has been on DOM
fractionation and radiocarbon
measurements
DOM Fractionation Procedure
isotopes
measured
Combustion/Extraction
Isolation Columns
After Aiken et al. (1992)
Fractionation favors isolation of hydrophobic
compounds (humics) which tend to be more
refractory
Longer environmental persistence of these
hydrophobic compounds may correlate to
radiocarbon age.
Fractionation Data
100%
90%
DOM Fractionation %
80%
70%
60%
50%
40%
30%
20%
Hydrophilic + Transphilic
Hydrophobic Acids (XAD 8)
10%
0%
Sacramento San Joaquin
River
River
Bacon
Island
Bouldin
Island
Twitchell
Island
Banks
Pumping
Plant
Radiocarbon Comparison of Surface DOM and Soil Organic Matter
2.00
Fraction Modern Carbon (fmc)
1.90
1.80
(Fraction Modern Carbon)
1.70
1.60
1.50
 14C 
 12 
 C
fmc  14 sample
 C
 12 
 C standard
1.40
1.30
fraction modern carbon
Source
DOC
XAD-8
Sacramento R
1.07, 1.10
San Joaquin R
1.09, 1.10
Old R
1.08, 1.53
Cache Cr
0.89
Missouri R
0.94-1.14
0.87-0.99
Mississippi R
1.06-1.09
*Hudson R
0.84-0.96
Others
1.06-1.11
0.77-1.40
Delta Island Soil Organic Matter
0.38-0.89
1.20
1.10
1.00
from Davisson (2002)
Accelerator Mass Spectrometry
* from Raymond and Bauer (2000)
River XAD-8 Fractions Are Younger Than Ag Drain Water
1.40
April-Oct 2003
1.30
Whole Water
XAD 8
1.10
1.00
14
C (fmc)
1.20
0.90
0.80
0.70
0.60
Banks
Hood Vernalis Bacon Bouldin Twitchell
Calculated 14C abundance in non-XAD-8 DOC fractions
indicate old or possibly fossil carbon sources
C non XAD8 
Calculated
14
C of non-XAD-8 DOC (fmc)
14
CWW  fDOCXAD8 14C XAD8
1  fDOCXAD8
14
Hood
Vernalis
1.20
0.80
0.40
0.00
April-Oct 2003
10
20
30
40
o
Maximum Daily Air Temperature ( C)
Sac. River and Aqueduct 14C abundance of XAD-8
fraction closely track each other
1.00
0.95
Jones Tract Breach June 2003
0.90
14
Aqueduct
Banks C XAD-8 (fmc)
y = 1.072x - 0.0724
R2 = 0.858
0.85
0.80
0.80
0.85
0.90
14
Sac.Hood
River C XAD-8 (fmc)
0.95
1.00
Simple Mass Balance Mixing Model Tends to UnderPredict 14C abundance of XAD-8 DOC Fraction
14
C mix
 X 1C1 14C1  X 2 C 2 14C 2  ...




 X i Ci


linear mixing model
1.2
*Input Flows
Ag Drains
C XAD-8 (fmc)
SJ River
1.0
0.9
14
Sac. River
1.1
Ag Drains
Rivers
Banks Pumping Plant
Predicted Banks
0.8
Other Streams
0.7
Apr-03
May-03
Jun-03
Jul-03
* Based on DSM2 daily mass flow estimates for all major Delta inflows
Aug-03
Implications from Simple Mass Balance Modeling
Delta Island agricultural drainage has minimum influence on
DOC at Banks
Increasing flow contributions from eastside of Delta or San
Joaquin River cannot account for 14C discrepancy
Modern-aged carbon is added to the XAD-8 fraction
between Hood and Banks
SUVA (L/mg-m)
Sac. River 2.13
Aqueduct
2.83
THMFP (µmol/mmol C)
7.45
9.08
Conclusions
For Sacramento and San Joaquin rivers, whole water
DOM predominantly has lower radiocarbon content than
corresponding XAD-8 fractions
The non-XAD-8 portion of DOM in these river waters
suggest old or fossil carbon inputs
Sacramento River and San Joaquin River have younger
XAD-8 fractions than Delta Island agricultural drain
waters
A conservative mixing model for DOM at Banks predicts
older carbon than is observed for most samples thus far
Results suggest young carbon is added between Hood
and Banks, which may explain increases in SUVA and
THMFP
Acknowledgements
Funding provided by the CALFED Bay Delta Program, State
Water Project Contractors and Department of Water
Resources
Twitchell Island
Banks Pumping Plant