Hans Paerl PhD
Hans Paerl PhD
Hans Paerl PhD
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Nitrogen-Eutrophication<br />
Nitrogen Eutrophication<br />
Dynamics in Estuaries<br />
<strong>Hans</strong> <strong>Paerl</strong>, UNC-CH UNC CH Institute of Marine Sciences, Morehead City, NC<br />
www.marine.unc.edu/<strong>Paerl</strong>lab
•<br />
Key Estuarine Nutrient Issues<br />
Primary production in estuarine waters is largely N limited;<br />
however some systems are N & P co-limited co limited or P limited<br />
•<br />
•<br />
N (& P) Over-enrichment Over enrichment linked to eutrophication<br />
Sources, forms and proportions of N loading are changing<br />
*<br />
e.g. point & non-point non point surface runoff, atmospheric deposition, groundwater<br />
•<br />
Ammonium is increasing as a N source<br />
Hypoxia, Increased wastewater loads, Ag runoff<br />
•<br />
Ecological Effects?*<br />
* nuisance algal blooms, toxicity, hypoxia/anoxia, food web alterations alterations
Fisher et al. 1998<br />
Nutrient limitation in the Chesapeake Bay<br />
Chesapeake<br />
(Fisher et al. 1998)
Nutrient limitation dynamics in the Neuse<br />
R. Estuary, NC<br />
Neuse R. Estuary<br />
Gallo 2004
Nitrate (μg N L -1 )<br />
1200<br />
1000<br />
800<br />
600<br />
400<br />
200<br />
0<br />
200<br />
150<br />
100<br />
50<br />
0<br />
200<br />
150<br />
100<br />
50<br />
Nitrate Ammonium<br />
Nitrate and Ammonium<br />
Concentrations in the<br />
Neuse R. Estuary, NC<br />
0<br />
Jan Feb Mar Apr May Jun Jul Aug<br />
<strong>Paerl</strong> et al. 2005;<br />
ModMon Project<br />
Jan Feb Mar Apr May Jun Jul<br />
0<br />
Aug<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
100<br />
80<br />
60<br />
40<br />
20<br />
Ammonium (μg N L -1 )
% of total measured N uptake<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
Jan Feb Mar Apr May Jun Jul<br />
Relative uptake of<br />
Ammonium, Nitrate<br />
and Urea in the NRE<br />
Ammonium<br />
Nitrate<br />
Urea<br />
Twomey et al. 2005
•<br />
•<br />
Conclusions (For Neuse R. Estuary)<br />
All forms of N are readily utilized<br />
Uptake of various N forms reflects<br />
their availability & concentrations
Ammonium is often a<br />
preferred N source,and<br />
it is increasing. What<br />
are the effects on phyto<br />
community<br />
structure?<br />
Chlorophyll a (µg L -1 )<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
C<br />
<br />
NH4<br />
NO3<br />
Nutrient Addition Bioassay Experiment, T1<br />
Neuse River, July 2003<br />
Upstream CMAX Downstream<br />
NH4 + NO3<br />
P<br />
NH4 + P<br />
NO3 + P<br />
<br />
<br />
NH4 + NO3 + P<br />
C<br />
NH4<br />
NO3<br />
<br />
NH4 + NO3<br />
P<br />
NH4 + P<br />
NO3 + P<br />
<br />
<br />
NH4 + NO3 + P<br />
C<br />
NH4<br />
NO3<br />
Twomey et al. 2005<br />
NH4 + NO3<br />
P<br />
NH4 + P<br />
NO3 + P<br />
NH4 + NO3 + P
All phytos<br />
Concentration<br />
(mg m-3 )<br />
cryptophytes<br />
15<br />
12<br />
9<br />
6<br />
3<br />
0<br />
5<br />
4<br />
3<br />
2<br />
1<br />
0<br />
Bogue Sound Bioassay August, 1996<br />
Chl a Fucoxanthin<br />
12<br />
Control Nitrate Ammonium<br />
Control Nitrate Ammonium<br />
15<br />
9<br />
6<br />
3<br />
0<br />
3<br />
2<br />
1<br />
0<br />
Control Nitrate Ammonium<br />
Alloxanthin<br />
5<br />
4<br />
Zeaxanthin<br />
Treatment<br />
Control Nitrate Ammonium<br />
diatoms<br />
cyanobacteria<br />
<strong>Paerl</strong> et al. 2006
N source can affect<br />
cyanobacterial dominance:<br />
Lake Njupfatet, Sweden<br />
Blomqvist et al. 1994<br />
+ ammonium-N<br />
ammonium<br />
+ nitrate-N nitrate
Lake Taihu<br />
3 rd largest lake in China. Increased N loads (dominated by<br />
ammonium) . Blooms have grown to “pea pea soup” soup conditions within a decade
Freshwater discharge and residence time matter as well<br />
Hydrologic controls of chl-a chl chl-a production and composition:<br />
SeaWiFS (SAS II) during low flow (’95) ( (’95) 95) and high flow (’96) ( (’96) 96) years<br />
spring ‘95 spring ‘96<br />
Harding et al. 2006
Chesapeake Bay phytoplankton<br />
composition by CHEMTAX –<br />
contrasting flow years<br />
spring '95<br />
spring '96<br />
summer '95<br />
summer '96<br />
Diatoms<br />
Dinoflagellates<br />
Cryptophytes<br />
Cyanophytes<br />
Chlorophytes<br />
Prasinophytes<br />
Haptophytes<br />
Adolph et al 2007
Nutrient cycling and food web implications<br />
Nutrient and<br />
Hydrologic drivers<br />
PHYTOPLANKTON<br />
COMMUNITY<br />
FORM of Limiting Nutrient<br />
(NO 3 - , NH4 + , DON)<br />
Nutrient Ratios, Residence Time<br />
Grazed<br />
Phytoplankton<br />
Species<br />
Nuisance / Toxic<br />
Phytoplankton<br />
Species<br />
Some Dinoflagellates<br />
Cyanobacteria<br />
Nutrient Regeneration<br />
Decomposition of POM<br />
Linkages Between Nutrient Inputs, Hydrology,<br />
Phytoplankton Community Composition, Grazing,<br />
Hypoxia and Fisheries Habitat<br />
Grazing and<br />
Water Column<br />
Carbon Recycling<br />
Carbon<br />
Deposition<br />
(POC)<br />
+<br />
DECREASED<br />
O 2 Depletion<br />
Potentials<br />
INCREASED<br />
O 2 Depletion<br />
Potentials<br />
-<br />
OXIC<br />
CONDITIONS<br />
Mixing<br />
PHYSICAL<br />
CONTROLS<br />
Stratification<br />
HYPOXIA<br />
ANOXIA
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
Management Implications<br />
In most estuaries, including regions of the SFO Bay N<br />
plays role as limiting nutrient.<br />
DIN utilization reflects supply rates: However, some<br />
forms (e.g., ammonium) may be preferred.<br />
Sources of N influence algal composition: Potential<br />
food web and biogeochemical implications<br />
Light-N Light N interactions may be important, especially in<br />
turbid waters<br />
Hydrology (storms, floods, droughts) and residence<br />
time are important interactive variables, especially for<br />
slower growing phytoplankton like cyanobacteria.<br />
cyanobacteria.<br />
Develop appropriate in in situ situ response assays and<br />
indicators to assess responses and impacts
Thanks to:<br />
L. Harding<br />
A. Joyner<br />
B. Peierls<br />
M. Piehler<br />
K. Rossignol<br />
L. Valdes<br />
P. Wyrick<br />
Estuarine & Coastal Indicators of Nutrient Enrichment<br />
www.unc.edu/ims/paerllab/<br />
www.unc.edu/ims/paerllab<br />
www.unc.edu/ims/paerllab/<br />
82667701<br />
& NSF, USDA, NCDENR, NC Sea Grant
Effects of Ammonium or Nitrate (10 μg N L -1 )<br />
Blomqvist et al. 1994<br />
additions (+P) on<br />
phytoplankton biomass in eutrophic Lake Erken, Sweden
Lake Okeechobee, Florida: Nutrient enrichment,<br />
water withdrawal, drought conditions. Lots more ammonium<br />
<br />
2007<br />
Photo, K. Havens
Expansion of<br />
Cylindrospermopsis<br />
Raciborskii<br />
Raciborskii<br />
Why?
Nutrient/light strategies of Cylindrospermopsis<br />
ylindrospermopsis raciborskii raciborskii<br />
High P uptake and storage capacity<br />
(Isvanovics Isvanovics et al 2000)<br />
N 2 Fixer<br />
High NH4 NH<br />
+ uptake affinity<br />
N additions (NH4 (NH<br />
+ NO x) ) often significantly increase growth (chl ( chl a<br />
and cell counts) and productivity (Presing Presing et al 1996)<br />
Tolerates low light intensities<br />
“Tracks Tracks” eutrophication (expand in waters w/ increasing turbidity)<br />
Can coexist in water column with other cyanoHABs<br />
(Fabbro Fabbro and Duivenvoorden 1996)
N stimulation of primary production in the<br />
Coastal W. Atlantic Ocean<br />
<strong>Paerl</strong> et al., 1999<br />
14 C-CO 2 Fixation (DPM * 10 4 )<br />
*<br />
0.6<br />
*<br />
0.4<br />
0.2<br />
0<br />
7.5<br />
5<br />
2.5<br />
0<br />
Control<br />
NO3<br />
*<br />
NH4<br />
PO4<br />
Fe + EDTA<br />
Fe + EDTA + NO3<br />
*<br />
Gulf<br />
Stream<br />
Inshore
DPM/ml<br />
N (+P) stimulation of primary<br />
production in the brackish<br />
Baltic Sea<br />
700<br />
600<br />
500<br />
400<br />
300<br />
200<br />
100<br />
Baltic Sea 2000, Bioassay A<br />
Primary Productivity<br />
Legend<br />
Day 1<br />
Day 2<br />
Day 3<br />
Control<br />
Mannitol<br />
N<br />
P<br />
Fe<br />
Fe+EDTA<br />
N+Fe<br />
P+Fe<br />
N+P<br />
Chlorophyll a (μg/l)<br />
0.13<br />
0.12<br />
0.11<br />
0.1<br />
0.09<br />
0.08<br />
0.07<br />
0.06<br />
0.05<br />
0.04<br />
0.03<br />
Baltic Sea 2000, Bioassay A<br />
Chlorophyll<br />
Control<br />
Mannitol<br />
N<br />
P<br />
Fe<br />
Fe+EDTA<br />
N+Fe<br />
P+Fe<br />
N+P
Distance Downstream (km)<br />
River Discharge (m 3 s -1 )<br />
40<br />
30<br />
20<br />
10<br />
0<br />
40<br />
30<br />
20<br />
10<br />
0<br />
40<br />
30<br />
20<br />
10<br />
0<br />
500<br />
400<br />
300<br />
200<br />
100<br />
0<br />
1994<br />
1995<br />
Phytoplankton functional group responses<br />
1996<br />
1997<br />
1998<br />
1999<br />
2000<br />
2001<br />
2002<br />
2003<br />
2004<br />
8<br />
6<br />
4<br />
2<br />
0<br />
12<br />
9<br />
6<br />
3<br />
0<br />
16<br />
12<br />
8<br />
4<br />
0<br />
Chlorophytes<br />
(µg L-1 )<br />
Cyanobacteria<br />
(µg L-1 )<br />
Dinoflagellates<br />
(µg L-1 )<br />
Bertha<br />
Fran<br />
Bonnie<br />
Dennis<br />
Floyd<br />
Irene<br />
Isabel
DIN DI<br />
What do the data show?<br />
Loading vs. primary production in a range of N. American<br />
and European estuaries<br />
(Nixon 1996)
N loading and algal production in the Neuse R. Estuary<br />
distance downstream<br />
from Streets Ferry Bridge (km)<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
Salinity (psu)<br />
chl a (ug L -1 )<br />
- -1 NOx (ug L )<br />
Floyd<br />
<br />
6/97 12/97 6/98 12/98 6/99 12/99 6/00<br />
20<br />
15<br />
10<br />
0<br />
200<br />
400<br />
600<br />
800<br />
>1000<br />
>30<br />
20<br />
10<br />
0<br />
5<br />
0