An Investigation into past and present An Investigation into past and present An Investigation into past and present An Investigation into past and present

sediment and nutrient dynamics of sediment and nutrient dynamics of sediment and nutrient dynamics of sediment and nutrient dynamics of

Lake Cootharaba and the Noosa River Lake Cootharaba and the Noosa River Lake Cootharaba and the Noosa River Lake Cootharaba and the Noosa River

CatchmentCatchmentCatchmentCatchment

Krystina Lamb and Nikita Tully

Supervisors: Dr Neil Tindale, Dr Peter Brooks, Vanessa Moscato, Peter Davies.

Noosa River Catchment CharacteristicsNoosa River Catchment CharacteristicsNoosa River Catchment CharacteristicsNoosa River Catchment CharacteristicsBegins in the Como escarpment, CooloolaNational Park, flows into Lake Cootharaba alongside Kin-Kin creek, then the Lower Noosa river joins the ocean at Noosa heads.

• Catchment area: 950km2 • Average depth: 1.2m• Pudding bowl shape• Lake surface area: 38km2 • Limited exchange

• Reference system - Ecosystem Health Monitoring Program• Freshwater & estuarine monitoring - SEQ &

Moreton Bay. • Total nitrogen above guideline limits• A to A- (elevated DIN) (EHMP 2006)• B+ (EHMP 2009)• B (EHMP 2010)

Nitrogen and PhosphorusNitrogen and PhosphorusNitrogen and PhosphorusNitrogen and Phosphorus

• Essential plant macro-nutrients.• Estuarine systems usually nitrogen limited (Carmargo and Alonso, 2006)• Elevated nutrients can result in algal blooms (Cloern, 2001)• Dissolved Inorganic Nitrogen - NH3, NO2-, NO3-• A warming climate has the potential to increase the

frequency cyanobacteria blooms (Wagner and Adrian, 2009)• Excess nitrogen can generate selective forces, changes in

trophic structure (Cloern, 2001)

Previous StudiesPrevious StudiesPrevious StudiesPrevious Studies

• Pilot study (2007-2009) found high nitrogen levels in the lake:� Water column -TN range: 0.12mg/L to 1.3mg/L, mean = 0.55mg/L +/-0.01� Organic (detritus and phytoplankton) 86%,

• Dissolved Inorganic Nitrogen (NH3, NO2-, NO3-) 13% (Rissik and Grinham, 2009).• Septic outfalls are unlikely contributors (Brooks, Sullivan & Tindale, 2009)• Wind driven resuspension and sediment processes (Longmore and Roberts, 2006).• Sediments are high in nitrogen (Rissik and Grinham, 2009). • The Upper Noosa River: high volume, low nutrient levels• Kin Kin, Cooloothin, and Elanda creeks (Disturbed catchments): lower

in volume, but higher nutrient levels.

AimsAimsAimsAims

• To monitor catchment and lake nutrient levels.• To identify and track sediment movement

through Lake Cootharaba.• To identify temporal changes to the

sediment profile of Lake Cootharaba. • To contribute to the production of a

preliminary mass balance, nutrient and sediment model that will increase our understanding of natural systems.

PurposePurposePurposePurpose

• Contribute to the preservation of the Noosa River system by investigating past and present nutrient dynamics and determining whether the lake is a natural nutrient sink, or if this is subject to anthropogenic acceleration.• Identify sources of nitrogen and inform

catchment management.

MethodsMethodsMethodsMethods

Surface water quality and flow monitoring• Fortnightly ambient monitoring

six sampling points• Event monitoring• Temperature, pH, D.O.,

E.C./salinity, TSS/Turbidity,TN, NH3, NO2-, NO3-, TP, PO4, T.O.C., Faecal Sterols, Coliforms.

• Standard Methods for Examination of Water and Waste Water.

Methods: Water qualityMethods: Water qualityMethods: Water qualityMethods: Water quality

Sediment nutrient flux and re-mobilisation• Resuspension experiments

Flux is inferred by comparing pore water and overlying water concentrations.• Catchment modelling.

Results will be combined to develop a mass balance nutrient model.• Nutrient levels in sediment cores, which will be dated.

Sediment Cores

Fortnightly Water Samples

Flood / Rain event Samples

Methods: Sediment collectionMethods: Sediment collectionMethods: Sediment collectionMethods: Sediment collection

Sampling method• Water samples will be collected via a grab technique and

suspended sediment will be filtered in the lab. • Sediment nutrient profile will be analysed at USC’s NATA

certified ‘Analytical Services’ lab. • Suspended sediment geochemical analysis will be done at

the University of Queensland using an Inductively Coupled Plasma - Mass Spectrometer (ICP-MS).

Methods: Sediment tracingMethods: Sediment tracingMethods: Sediment tracingMethods: Sediment tracing

Sediment tracking• Multiple samples from each sediment sampling site will be

combined into a single representative sample for analysis for nutrient profile, and major and trace element geochemistry, including metals.

Methods: Sediment datingMethods: Sediment datingMethods: Sediment datingMethods: Sediment dating

Sediment dating• Up to 10 grab samples or cores from the 6 sites selected for

water quality analysis will be collected and a representative sample of sedimentation in those sites will be chosen for dating using 210Lead/137Caesium dating techniques at ANSTO (Australian Nuclear Science and Technology Organisation).

Proposed OutcomesProposed OutcomesProposed OutcomesProposed Outcomes

• Gain understanding of the potential of lakes to act as nutrient sinks.• Determine whether temporal changes in sediment nutrient

levels have occurred.• Clarify spatial distribution of sediment and nutrient

sources.• Generate valuable water quality and flow data.• Contribute knowledge to help catchment management

evaluate the health and stability of the Noosa River.• Develop a mass balance sediment and nutrient model.

Partners and ContributorsPartners and ContributorsPartners and ContributorsPartners and ContributorsFunding▫ Federal Government - Caring for our Country▫ Sunshine Coast Regional Council▫ Australian Institute of Nuclear Science and Engineering

(sediment dating, travel and support)Partners▫ Noosa and District Landcare and Waterwatch▫ SEQ Catchments▫ SEQ Healthy Waterways Partnership▫ DERM – Elanda Point Rangers▫ Community WaterwatchVolunteers▫ UQ

ReferencesReferencesReferencesReferencesBrooks P, Sullivan D and Tindale N (2009) Lake Cootharaba Nitrogen Project Study (University of the

Sunshine Coast sub-project report)

Camargo JA and Alonso AA (2006) Ecological and toxicological effects of inorganic nitrogen pollution in aquatic ecosystems: A global assessment, Environment International, 32(6): 831-849.

Cloern JE (2001) Our evolving conceptual model of the coastal eutrophication problem, Marine Ecology Progress Series, 210: 223-253

Ecosystem Health Monitoring Program (2006)

Ecosystem Health Monitoring Program (2009)

Rissik D and Grinham A (2009) Lake Cootharaba Nitrogen Project study: In lake Processes. A report commissioned by Healthy Waterways Partnership on behalf of Noosa and District Landcare Group Inc.

LongmoreAR and Roberts S (2006) Importance of Sediment Nutrients in the Gippsland Lakes - A report for the Gippsland Task Force. (http://www.gippslandlakestaskforce.vic.gov.au/research.htm)

Wagner C and Adrian R (2009) Cyanobacteria dominance: Quantifying the effects of climate change, Limnology and Oceanography, 56 (2): 2460-2468

Any Questions?Any Questions?Any Questions?Any Questions?