an ongoing study to examine the effect of changing inorganic nitrogen loading on a phytoplankton...
DESCRIPTION
From Fall 2009- An ongoing study to examine the effect of changing inorganic nitrogen loading on a phytoplankton communityTRANSCRIPT
AN ONGOING STUDY TO AN ONGOING STUDY TO EXAMINE THE EFFECT OF EXAMINE THE EFFECT OF CHANGING INORGANIC CHANGING INORGANIC
NITROGEN LOADING ON A NITROGEN LOADING ON A PHYTOPLANKTON COMMUNITYPHYTOPLANKTON COMMUNITY
Daniele Daniele
BakerBaker
www.waterandwastewater.com
http://cisbc.info/activities/PublishingImages/algae-2.jpg
OBJECTIVESOBJECTIVES
ONONDAGA LAKEONONDAGA LAKE
o Historically oligo-mesotrophico Flushes 4 times per year to Seneca
Rivero Watershed 642 km2 , contains 450,00
peopleo Three tributaries = 70% of water input
o (Onondaga, Ninemile and Ley Creeks
o Morphometry
o Maximum depth: 19.5 m
o Surface area: 12.0 km2
o Volume: 131 X 106 m3
A HISTORY OF POLLUTIONA HISTORY OF POLLUTION
o Syracuse area was settled in the 1700sSyracuse area was settled in the 1700so Salt deposits spurred large scale productionSalt deposits spurred large scale production
o Resulted in rapid industrial and population Resulted in rapid industrial and population
growth leading to…growth leading to…o Industrial pollutionIndustrial pollutiono Wastewater pollutionWastewater pollution
Wastewater Effects on the Lake (timeline):
1890- Cold water fishery lost
1940- Swimming banned (fecal coliform, total phosphorus and clarity)
1994- Lake and sediment added to the EPA Superfund National Priority List
EFFECTS OF NUTRIENT LOADINGEFFECTS OF NUTRIENT LOADING
Eutrophi
Eutrophi
cc
o Large phytoplankton blooms
o Anoxic bottom waterso Toxic levels of
ammonium (NH4+) and
nitrite (NO2-)
o Loss of cold water fish
Not actually Onondaga
CLEANING IT UPCLEANING IT UP
o METRO effluent METRO effluent o 80% of yearly TN load 80% of yearly TN load o 68% of TP68% of TPo During summer Metro largest During summer Metro largest
single inflow to the lakesingle inflow to the lake
o 1998- 1998- Amended consent Amended consent
judgment against METROjudgment against METROo Decrease loading over 15 Decrease loading over 15
years years o 3 phases ($380 mil)3 phases ($380 mil)
CHANGING LAKE CHANGING LAKE CONCENTRATIONSCONCENTRATIONS
o [NH[NH44++] and [NO] and [NO33
--] changed rapidly ] changed rapidly
in lakein lakeo Ratio of NHRatio of NH44
++ : NO : NO33-- reversed reversed
between Regime 3 and 5between Regime 3 and 5
5:1 5:3 2:5NH4+: NO3
-
Regime
3 4 5
Yearly
Ave
rge N
Conc
(uM
)
0
50
100
150
200
250
300
350
NH4 Nox
OBJECTIVESOBJECTIVES
MODEL POST-AUDITMODEL POST-AUDIT
Completed a post-audit of a N model for Onondaga Lakeo Model developed for 1990-1991 data (by Upstate
Freshwater Institute)o Used to test the changes in N cycling as a result of
various loading reductions scenarios from METRO
o Extended the model testing for another 17 years (1989, 1992-2007)
MODEL PERFORMANCEMODEL PERFORMANCE
o Model performed well in 1992
o Near the period (1989 + 1990) used for calibration and verification
MODEL PERFORMANCEMODEL PERFORMANCE
Did the model oversimplify the biology of the lake?
o Fit is poorero 2005 farther
from the period (1989 + 1990) used for calibration and verification
MODEL PERFORMANCEMODEL PERFORMANCE
Improved RMSE by 47% for hypolimnetic NH4+
predictions and by ~14% for NOX predictions in both layers.
1. Anoxic period2. Sediment release rate3. Algal uptake
Three new mechanisms added to the
model:
Improved Model Performance (2005)
OBJECTIVESOBJECTIVES
EFFECTS ON PHYTOPLANKTON EFFECTS ON PHYTOPLANKTON ASSEMBLAGEASSEMBLAGE
N Loading from Metro has decreased and changed since 1989
NH4+ : NO3
- is lower than ever before
How will this change affect phytoplankton?
Change in species? Toxicty? Food source?
N UPTAKE AND PREFERENCESN UPTAKE AND PREFERENCES
NO3- NO2
- NH4+ Amino Acids
Phytoplankton Cell Wall
NH4+NO3
-
N UPTAKE AND PREFERENCESN UPTAKE AND PREFERENCES
NO3- NO2
- NH4+ Amino Acids
Phytoplankton Cell Wall
NH4+NO3
-
Diatoms prefer NO3-
Some Chlorophyta +Cyanobacteria prefer NH4
+
Year
98 99 00 01 02 03 04 05 06 07 08 09 10 11
Rel
ativ
e B
iom
ass
0.0
0.2
0.4
0.6
0.8
1.0 Charo- Zygnematophyceae Chloro- Chlorophyceae Mamiellophyceae Nephroselmidophyceae Trebouxiophyceae UlvophyceaeCrypto- CryptophyceaeCyano- CyanophyceaeDino- DinophyceaeEugleno- EulgenophyceaeOchro- Bacillarophyceae Chrysophyceae Synurophyceae Xanthophyceae
Regime 3 Regime 4 Regime 5
PHYTOPLANKTON TRENDSPHYTOPLANKTON TRENDS
INCREASE DECREASE
Charo.r2= 0.051p= 0.4
r2= 0.11p= 0.3
Dino.
Crypto. r2= 0.40p= 0.01
Cyano.
r2= 0.85p= <0.001
Chloro.
r2= 0.62p= 0.5
r2= 0.61p= 0.001
Ochro.
= No Significant Change
PREDICTED VS. ACTUAL PREDICTED VS. ACTUAL ASSEMBLAGE CHANGES ASSEMBLAGE CHANGES
Expected change in divisions over the study period…
X
OBJECTIVESOBJECTIVES
OBJECTIVES OF MY PROPOSED OBJECTIVES OF MY PROPOSED RESEARCHRESEARCH
GOAL: Quantify the N preferences of the phytoplankton community.
How? Measure the rate and total NH4+ and NO3
- uptake of the community several times during summer.
o How fast can they take up NH4+
and NO3- (Kv)?
o How much total NH4+ and NO3
- can they uptake (Vm)
o Which species are dominating each phytoplankton community sample?
HOW TO MEASURE N UPTAKEHOW TO MEASURE N UPTAKE
RESULTS OF UPTAKE EXPERIMENTRESULTS OF UPTAKE EXPERIMENT
o P limited?o Average N:P of phytoplankton
15:1 (Redfield ratio)o Currently > 40:1
o Tested P limitation o Added P to make 15:1 o No increase in N uptake
between treatments with and without added P
d) 150- Amm- Onon (9)
Hours
1 2 3 4 5 6 7 8 9
[N]
uM
0
20
40
60
80
100
120
NH4+NO3-
o No decreasing trend, indicates no N uptake of NH4+ or
NO3- after 8 hours
o Largest [NH4+] spike should show greatest N uptake
WHY NO NITROGEN UPTAKE?
Why not allow phytoplankton to grow before measuring N uptake?
o Control sampleso Originally in media with best
ratio of all nutrientso Placed in environment with
huge nutrient limitation
o Onondaga Lakeo May be acclimated to slow
nutrient uptake o And “shocked” by new lab
environment
Is their a different approach that would answer my research question?
OBJECTIVESOBJECTIVES
SAME QUESTION, NEW APPROACHSAME QUESTION, NEW APPROACH
How did the change in NH4+ : NO3
- affect phytoplankton?
Change in species? Toxicity? Food source?Grow phytoplankton in the lab on 3 different
treatments (3 regimes)
Two different experiments 1. Growth experimentso Which species are the most competitive for each
regime?2. Uptake experimento How does N uptake vary between regimes and
species?
CHOOSING STUDY SPECIESCHOOSING STUDY SPECIES
Present in
Samples
Data for every year
Have trend
with N or P
loading
Increased with timeDecrease
d with time
P driven?N driven?P driven?N driven?
1. GROWTH EXPERIMENTS1. GROWTH EXPERIMENTS
o Spike each species with nutrients (3 different treatments)
o Adjust only NH4:NO3:P
3 separate experiments will estimate…
A. Growth dynamics
B. Competition
C. Changes in cell nutrient and toxin content
b) Decreasing Trend
Treatment
3 4 5
Gro
wth
Rat
e (
per
day
)
0
2
4
6
8
10P DrivenN Driven
1A. GROWTH DYNAMICS 1A. GROWTH DYNAMICS EXPERIMENTEXPERIMENT
o Grow species on set amount of substrateo Methods:o Measure fluorescence daily o Biweekly samples
o Cell counts (size, SA, V)o Inorganic nutrients
o Compare btw species and treatmento Growth rate, peak biomass 1
2
34 5
[Substrate]
Chl.
a) Increasing Trend
Treatment
3 4 5
Gro
wth
Rat
e (
per
day
)
0
2
4
6
8
10P DrivenN Driven
1B. COMPETITION STUDY1B. COMPETITION STUDY
o Spike all four species into each treatmento Methods:o Sample for cell counts dailyo Calculate % compositiono Compare % composition between treatments
Treatment
3 4 5
% C
om
po
sitio
n
0
20
40
60
80
100
P DrivenN Driven
P DrivenN Driven
Increasing
Decreasing
Treatment
3 4 5
Tox
icity
(
L-1 )
0
100
200
300
400
500
1C. CELL CONTENT EXPERIMENT1C. CELL CONTENT EXPERIMENT
o Allow species to grow long-term in semi-continuous cultureso Methods:o Sample at the beginning and end
o N:P (P limitation) o C:Chl (C limitation)
o Compare metrics after long-term incubation
o C:N (N limitation)o Toxicity (both cyanobacteria can produce toxins)
Treatment
3 4 5
C:C
hl
0.0
0.5
1.0
1.5
2.0
2.5
Treatment
3 4 5
N:P
0
2
4
6
8
10
12
14
16
18
Treatment
3 4 5
C:N
0
2
4
6
8
Treatment
3 4 5
Tox
icity
(
L-1 )
0
100
200
300
400
500
Treatment
3 4 5
Tox
icity
(
L-1 )
0
100
200
300
400
500
2. N UPTAKE EXPERIMENT2. N UPTAKE EXPERIMENT
o Measure N uptake of species grown on 3 different treatments
o Which species has fastest and largest uptake of NH4+
and NO3- ?
o How does treatment effect N uptake?o Half-saturation (Ks)o Max uptake rate (Vm)o Relative Preference Index (RPI)
𝑉= 𝑉𝑚 ∙ 𝑆𝐾𝑠 + 𝑆
2. N UPTAKE EXPERIMENT2. N UPTAKE EXPERIMENT
o N uptake and competition o KS will be more important than Vm as
[NH4+] decrease (i.e. most recent years)
o Vm for NO3- will be more important at
higher [NO3-]
Decreasing
↓
↑Increasing
Increasing
↓
↑Decreasing
2. N UPTAKE EXPERIMENT2. N UPTAKE EXPERIMENT
o N uptake and treatment effecto Lag time to ‘turn on’ pathways to utilize
nitrogen source when previously unexposed
o Phytoplankton grown in treatment 3 (low NO3
-) will have a lag time (high KS) for NO3-
o Small or no lag time with NH4+ (preferred)
DOGGIE BAG (I.E. TAKE DOGGIE BAG (I.E. TAKE HOME)HOME)
o Since 1989 o NH4
+ : NO3- has decreased
from 5:1 to 2:5o Phytoplankton community
has changedo NH4
+ : NO3- should be
affecting phytoplankton community
o World Wideo NH4
+ loading decreasing + urea loading increasingo Stoichiometry is IMPORTANT
o % toxic species and toxin production is correlated with changing ratio of N forms
o Are we really solving the problem just decreasing TN loads?