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Presentation at "The River, the Bay and the Strait" public forum on 5 October, 2008 in Hervey Bay.
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Phosphorus in the Mary and vulnerability of storages to algal
blooms
Presentation to the River, the Bay and the Strait Forum
Presenter: Graeme Esslemont (Burnett Mary Regional Group)
Date: Wednesday 5th October 2008
Why I have been asked to speak today?
Cleaner Creeks Cooperative Objectives:
1) Support stakeholders who are seeking voluntary initiatives to improve water quality in local streams (PAP 2).
2) Coordinated provision of reliable training and technical support, and data management (Wide Bay Water Laboratory, Burnett Mary Regional Group).
3) Development of a stakeholder supported dataset at an appropriate scale to identify water quality improvements.
Steering Meeting: Andrew Rickert, Michael Walker (WBWC), Brad Wedlock, Steve Burgess, Glenda Pickersgill, Deb Seal (MRCCC)
Events Monitoring – Events Monitoring – When sediment, When sediment, nutrients & nutrients & herbicides enter the herbicides enter the riverriver
Sediments - Loads
0
200
400
600
800
1000
1200
1400Discharge (cumecs)
TSS (mg/L) at LBTotal Event Discharge (ML) 400,220Number of samples 11TSS Load (Tonnes) 71,660TP Load (Tonnes) 54
FRP Load (Tonnes) 7.6TN Load (Tonnes) 465NO2 Load (Tonnes) 3.5
NOx Load (Tonnes) 171NH3 Load (Tonnes) 30NO3 Load (Tonnes) 167
Tracing P in river sediments for target setting.
Objectives
1) Identify variations of P in river sediments across the region, and identify sections of river with anomalous concentrations of P.
2) Use background ratios to as a guide for target setting, in negotiations with stakeholders for achieving on ground actions.
3) Suggest the application of geochemical ratios for measuring offsite exports of P from farms, to monitor against targets. This might particularly apply to stakeholders who have not embraced hydrological approaches for monitoring loads.
How does P get into sediment?
• Insoluble oxide properties.• Assimilated by living organisms• Included with soil minerals:
– Exchangeable (anion exchange with clays)– iron oxides (e.g. chemical adsorption or inclusion in
gel goethite and other iron minerals)– Organic (e.g. humic acids, particulate organic matter,
iron-reducing bacteria).– Mineral (apatite).
Iron bound PBurnett Mary - Sodium Dithionite (goethite) - P/Fe
y = 0.016x + 3.825
R2 = 0.550
0 200 400 600 800 1000 1200
Fe (mM/g)
P (m M
/g)
Organic bound PBurnett - Aquaregia (organic, apatite)- P/C
y = 0.000x + 3.880
R2 = 0.063
0102030405060708090
100
0 5000 10000 15000 20000 25000
C (mM /g)
P (mM
/g)
Soil Bacteria:
C/N ratio of 17-8 in fungal & bacterial
biomass (Swift et al., 1979)
Redfield C/N in phytoplankton = 6.6 –
7
Fine Particulate Organic Matter = 8 -
267
Carbon/Nitrogen Ratio
y = 14.04x + 0.58
R2 = 0.83
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70
Total Carbon (mM/g)
Tota
l Nitr
ogen
(mM
/g)
The role of carbon in Australian Rivers and Floodplains
Eucalyt carbon
river red gum leaf
0.0
0.1
0.2
0.3
0 20 40 60 80
Days
Cu
mu
lativ
e o
xyg
en
co
nsu
mp
tion
as
mo
les
of
O2
/C
nutrient supplemented nutrient depauperate
Pasture carbon
couch grass
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0 20 40 60 80
Days
Cum
ulat
ive
oxyg
en
cons
umpt
ion
as m
oles
of
O2/
C
nutrient supplemented nutrient depauperate
Aquatic plant
Carbon
milfoil
0.0
0.1
0.2
0.3
0.4
0.5
0 20 40 60 80
Days
Cu
mu
lativ
e o
xyg
en
co
nsu
mp
tion
as
mo
les
of
O2
/C
nutrient supplemented nutrient depauperate
Where is Phosphorus enriched in
river sediment?
Soil lossLosing ground ……….. Reduced farm product-ivity
Wetlands can help…
Be aware of over-topping
of fine sediment
and soluble nutrients
Recommended