Download - Oral Presentation for defense final
Urea Release by Intermittently Saturated Sediments from a
Coastal Agricultural Landscape
1University of Maryland Eastern Shore, Princess Anne, MD 21853 2USDA-ARS, Pasture Systems and Watershed Management Research Unit, University Park, PA
16802
Thesis Advisory CommitteeDr. Eric B. May1, Co-advisorDr. Arthur L. Allen1, Co-advisorDr. Ray B. Bryant2
Dr. Fawzy M. Hashem1
Mason D. King1
1950 1960 1970 1980 1990 2000 2010 20200%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Ure
a-N
as a
% o
f Tot
al N
Data from USDA Economic Research Service Image adapted from WHOI Harmful Algal Bloom website
HABs pre-1972
Puerto Rico
Hawaii
Alaska
HABs present
Puerto Rico
Hawaii
Alaska
Year
Neurotoxic shellfish poisoningParalytic shellfish poisoning CiguateraBrown tide
Pfisteria complexFarmed fish killsAmnesic shellfish poisoning
Introduction
Urea
Why the concern about urea?ABCDEFGHIJKLMNOP
Microplankton Species
Nitrate
Dominant
Urea
Dominant
(Solomon et al., 2010; Glibert et al., 2001, 2005, 2006, 2014; Howard et al., 2007; Thessen, et al. 2009; Berman & Chava, 1999; Finlay et al. 2010)
• Some phytoplankton exploit urea > inorganic N
• Loading could shift community structureo HABs
• Can enhance growth rate or toxicityo Including mid-Atlantic coasts and
Chesapeake Bay
• High urea concentrations in agricultural watershedso Highest values reported in
agriculture-dominated tributaries to the Chesapeake Bay and the MD coastal baysChesapeake
BayCoastal
Bays
Delmarva Peninsula
(Glibert et al. 2005; Solomon et al. 2010)
• Agriculture is 48% of land use on the Delmarva Peninsula
• BUT urea hydrolyzes rapidly in soilo Fertilizero Manure
• Runoff and leaching losses are briefo About 1 week under normal
conditions
(Tzilkowski, 2013; Han et al., 2015; Kibet et al., in review)
Window when urea or poultry
litter would normally be
applied
• Urea concentrations under baseflowo Peak mid to late summero Wetland streams > agricultural streams o Highest concentrations in agricultural drainage ditches
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
Ure
a-N
(mg
L-1)
*
*
*
*
*
Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecMonth
First and second order
streams
(Tzilkowski 2013)
• Urea–N in ditches up to 0.220 mg L-1
• High concentrations unexplained by external inputso Shallow groundwater
(leaching)o Surface runoffo Wet atmospheric
deposition• Apparently autochthonous
origin
Urea in shallow groundwater
Groundwater data courtesy of Leonard Kibet
0.00 0.01 0.02 0.03 0.04 0.05
Urea-N (mg L-1)
Objective:• Assess urea release by intermittent sediments
from an agricultural landscape
Hypothesis: • Higher urea concentrations would result from
1. Wetland and drainage ditch sediments2. N enriched conditions3. Higher temperature
Objectives & Hypothesis
Intermittent freshwater sediments for a mesocosm experiment were collected from a farm and a nearby wetland.
Methods
Washed, screened, autoclaved sand used as a control sediment
Mesocosm sediments were subsampled before and after experimental saturation and incubation
Sediment urea–N, NH4+–N, and NO3
-–N extracted with 2 M KCl
Mesocosms placed in water baths
Saturated with distilled water or N solution (NH4
+–N or NO3-–N)
Surface water samples were taken at time intervals
Surface water samples and sediment subsamples were analyzed colorimetrically for urea–N, NH4
+–N, and NO3
-–N
The experiment was replicated three times
Data analyzed o General linear model (GLM)o Linear mixed model (LMM) with
repeated measures, o Paired T tests
5 sites x 3 temperature treatments x 5 solution types = 75
conditionsControl 16°C Distilled water
Agriculture ditch 21°C NH4+–N 1.52mg L-1
Cleaned agriculture ditch 27°C NH4+–N 3.00 mg L-1
Forest NO3-–N 2.59 mg L-1
Wetland NO3-–N 5.07 mg L-1
Storms on Aug 10 & 11, 2015 filled dry ditches
Conditions analogous to mesocosm experiment
Automatic samplers deployed 18 h after first rainfall
Water drawn at same intervals as mesocosm experiment
Analyzed for urea–N, NH4+–N,
and NO3-–N
Results
Higher urea–N and NH4+–N in forest and wetland
Higher NO3-–N in uncleaned ditch and cleaned ditch
0.00
0.20
0.40
0.60
0.80
1.00
1.20
0.00
5.00
10.00
15.00
20.00
25.00
30.00
CBC B
AA
D
B
A
C CD
CB
A A
Urea-N Nitrate-N Ammonium-N
Ure
a–N
(m
g kg
-1)
NO
3-–N, N
H4+–N (m
g kg-1)
Initial sediment N concentration by site (n = 45, GLM).
0.00
0.02
0.04
0.06
0.08
BB
C B BB
B BCCD BC
B BA
AB A
AA
AA
A AA
A
B CD C C C
Control Cleaned ditch Uncleaned ditch Forest Wetland
Urea
–N (m
g L-
1)
0.00
0.50
1.00
1.50
2.00
2.50
AB BC CD BC B BCA A
A A A A
A AB BC ABAB
ABA A
AB A AA
B C D C C C
NH4
+–N
(mg
L-1)
0 12 24 36 48 60 720.00
3.00
6.00
9.00
12.00
15.00
BC BC C C B BB B B B B B
A
AA
A
A A
A
A AA
A A
C C C C B B
Hours
NO
3-–N
(m
g L-
1)
Effect of site on surface water N(n = 15, LMM).
Higher urea–N in ditch mesocosms, not wetland mesocosms
Also higher NO3-–N in ditch mesocosms
Rapid NO3-–N loss
0 12 24 36 48 60 720.00
5.00
10.00
AA A
A
A AB
B B AAB AC C C B BC BC
C C B BC BC C C BC B
Hours
NO
3-–N
(mg
L-1)
Effect of N enriched saturating solution(n = 15, LMM).
Higher urea–N in ditch mesocosms, not wetland mesocosms
Increase and loss of NO3-–N
0.00
0.02
0.04
0.06
0.08
B BBB
BBA A
B B
Distilled water Ammonium- low Ammonium- highNitrate- low Nitrate- high
Urea
-N (m
g L-
1)
0.00
1.00
2.00
3.00
C C C C BC C
C C C CBC C
A A A A A A
B B B B BB
C C C C CC
NH4
+–N
(mg
L-1)
No consistent and clear effect on urea–N
0.00
0.02
0.04
0.06
0.08
AA
AA
A
BAB B B B
BB B
B B
16°C 21°C 27°C
Urea
-N (m
g L-
1)
0.00
1.00
2.00
3.00
AA
A
AB B BB B B
NH4
+–N
(mg
L-1)
0 12 24 36 48 60 720.00
2.00
4.00
6.00
8.00
AA
C B
ABAB
B BB
B A A
Hours
NO
3-–N
(mg
L-1)
Effect of temperature on surface water N (n = 25, LMM).
More urea–N at high temperature
More NH4+–N at high temperature
NO3-–N dynamics increase with temperature
-0.25
0.00
0.25
0.50
0.75
Ditch 1 (soy, uncleaned) Ditch 2 (soy, uncleaned)Ditch 3 (soy, uncleaned) Ditch 4 (corn, cleaned)Ditch 5 (soy & corn, cleaned)
Urea
-N (m
g L-
1)
0.00
2.00
4.00
6.00
8.00
NH4
+–N
(mg
L-1)
6 18 30 42 54 66 78 90 102 114 126 1380.00
1.00
2.00
3.00
4.00
Hours after first rainfall
NO
3-–N
(m
g L-
1)
N in farm ditches after Aug 10 & 11, storms
High urea–N concentrations
NH4+–N related to ditch cleaning and/or urea–N?
NO3-–N rapidly lost
0.00
0.50
1.00
A
B
B
ASeries1 0.36 0.41 0.33 0.97 1.00
Ure
a–N
(mg
kg-1
)0.00
10.00
20.00
30.00
B
A
A
A AA
B BB B
NO
3-–N
(mg
kg-1
)
0.00
10.00
20.00
30.00
NH
4+–N
(mg
kg-1
)
Sediment N by site before and after mesocosm experiment (n = 45, paired t test).
Before After
Change in urea–N is variable
NO3-–N
decreased
Main controls on urea (Bogard et al., 2012)Discussion• Results reflect active cycling, not simple diffusion from inert urea pool in sediments
• Bacterial metabolism and decomposition of organic matter produce urea in sedimentso Low C:No Warm temperatures
• In ditch sediments urea may cycle rapidly. Some is lost to surface water where it accumulates due to low transformation rates
• Agricultural watersheds can have 9 m of ditch for every 1 m of stream length
• Urea release by ditch sediments explains high concentrations well after fertilizationo Indirect role of agricultural management (lowered
sediment C:N ratio)
(Tzilkowski, 2013)
Conclusions
• Urea in stagnant farm ditches may be exported by stormflow ando Shift phytoplankton
communitieso Trigger HABs and/or toxin
production
(Glibert et al., 2006, 2014; Finlay et al., 2010)
AcknowledgementsKevin Miller, Lou Saporito, Terry Troutman, Janice Donohoe, Peter Sang, Joan Weaver, Curt Dell, Anthony Buda, Lindsey Hughes, Nancy Chepketer, Tedra Booker, Nelson Kimutai, Derrick Cheruiyot, Wahed Abdullah, Peter Kim, Solomon Kirongo, Don Mahan, Tracie Bishop, Earle Canter, Jennifer Ossai, Caitlin LaComb, Wilmelie Cruz-Marrero, the UMES Department of Food, Agriculture, and Resource Science, the UMES Department of Natural Sciences, and the NRCS-USDA CIG Program.
References available upon request
Berman, T., & Chava, S. (1999). Algal growth on organic compounds as nitrogen sources. Journal of Plankton Research, 21(8), 1423–1437.
Bogard, M. J., Donald, D. B., Finlay, K., & Leavitt, P. R. (2012). Distribution and regulation of urea in lakes of central North America. Freshwater Biology, 57(6), 1277–1292.
Finlay, K., Patoine, A., Donald, D. B., Bogard, M. J., & Leavitt, P. R. (2010). Experimental evidence that pollution with urea can degrade water quality in phosphorus-rich lakes of the Northern Great Plains. Limnology and Oceanography, 55(3), 1213–1230.
Glibert, P. M., Harrison, J., Heil, C., & Seitzinger, S. (2006). Escalating worldwide use of urea – A global change contributing to coastal eutrophication. Biogeochemistry, 77(3), 441–463.
Glibert, P. M., Magnien, R., Lomas, M. W., Alexander, J., Fan, C., Haramoto, E., … Kana, T. M. (2001). Harmful Algal Blooms in the Chesapeake and Coastal Bays of Maryland, USA: Comparison of 1997, 1998, and 1999 Events. Estuaries, 24(6), 875–883.
Glibert, P. M., Maranger, R., Sobota, D. J., & Bouwman, L. (2014). The Haber Bosch–harmful algal bloom (HB–HAB) link. Environmental Research Letters, 9(10), 105001.
Han, K., Kleinman, P. J. A., Saporito, L. S., Church, C., McGrath, J. M., Reiter, M. S., … Bryant, R. B. (2015). Phosphorus and nitrogen leaching before and after tillage and urea application. Journal of Environmental Quality, 44, 560–571.
Howard, M. D. A., Cochlan, W. P., Ladizinsky, N., & Kudela, R. M. (2007). Nitrogenous preference of toxigenic Pseudo-nitzschia australis (Bacillariophyceae) from field and laboratory experiments. Harmful Algae, 6, 206–217.
Kibet, L., Bryant, R., Buda, A., Kleinman, P., Saporito, L., Allen, A., … May, E. (2015). Persistence and surface transport of urea-nitrogen in a coastal plain soil. Journal of Environmental Quality, In review.
Solomon, C. M., Collier, J. L., Mine Berg, G., & Glibert, P. M. (2010). Role of urea in microbial metabolism in aquatic systems: a biochemical and molecular review. Aquatic Microbial Ecology, 59(1), 67–88. 7
Thessen, A. E., Bowers, H. A., & Stoecker, D. K. (2009). Intra- and interspecies differences in growth and toxicity of Pseudo-nitzschia while using different nitrogen sources. Harmful Algae, 8(5), 792–810.
Tzilkowski, S. S. (2013). Watershed scale controls on urea transport in a coastal plain river network. Pennsylvania State University Thesis.
References
Extra material
Control Cleaned ditch
Uncleaned ditch Forest Wetland Distilled
waterNH4
+–N low
NH4+–N
highNO3
-–N low
NO3-–N
high16°C 21°C 27°C
N typeUrea–N
Min <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015Max 0.182 0.477 0.332 0.374 0.248 0.256 0.477 0.334 0.332 0.209 0.133 0.334 0.477
NH4+–NMin <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 0.14 <0.10 <0.10 <0.10 <0.10 <0.10Max 4.32 14.22 8.53 8.16 7.57 14.22 11.08 8.53 10.13 7.55 5.56 8.53 14.22
NO3-–NMin <0.20 0.33 0.45 0.31 <0.20 0.22 <0.20 <0.20 0.47 0.24 <0.20 <0.20 <0.20Max 7.81 106.10 81.36 9.67 21.32 81.36 73.40 73.21 75.44 106.10 37.25 73.21 106.10
…..……………………………………………………………………………………….. mg L-1 ……………………………………………………………………………………………………………..
Sediment Saturating solution Temperature