How Healthy is Moreton Bay, and its Rivers and Creeks? Angela Grice, Francis Pantus, Dan Wruck & Bill Dennison CRC for Coastal Zone Estuary & Waterway Management Adrian Jones & Ivan Holland

Outline Background Background Pressures Pressures Impacts Impacts Response Response Ecosystem Health Monitoring Ecosystem Health Monitoring Oxley Creek Oxley Creek Health of the rivers Health of the rivers Health of Moreton Bay Health of Moreton Bay

NorthStradbrokeIsland Redcliffe BribieIsland MoretonIsland BrisbaneRiver LoganRiver PineRiver CabooltureRiver Moreton Bay Moreton region has 2 million people and is the fastest growing region in the countryMoreton region has 2 million people and is the fastest growing region in the country Moreton Bay receives input from Brisbane, Logan, Caboolture and Pine RiversMoreton Bay receives input from Brisbane, Logan, Caboolture and Pine Rivers The Brisbane River has theThe Brisbane River has the -largest catchment of all regions -highest population density -highest sewage inputs OxleyCreek

Rivers and Bay are important to us … Trawling Waterskiing Swimming Port of Brisbane Fishing at Luggage Pt Outfall

… and everyone else!

Population expansion in the region over the past half century is one of the most rapid in the world and provides one of the major pressures to ecosystem health Population Growth is a major pressure

Sewage discharges concentrated in Brisbane River & Bramble Bay Largest sewage discharge = Luggage Pt. at mouth of Brisbane R.Largest sewage discharge = Luggage Pt. at mouth of Brisbane R. Oxley Creek = second largestOxley Creek = second largest 3 significant discharges into Bramble Bay and Hayes Inlet from Pine Rivers, Redcliffe and Brisbane City3 significant discharges into Bramble Bay and Hayes Inlet from Pine Rivers, Redcliffe and Brisbane City Multiple minor discharges scattered throughout tidal reachesMultiple minor discharges scattered throughout tidal reaches

Land area 000’s ha Increasing land-use Sown pasture Cropped land and fertilizer application Fertilizer 000’s t yr -1 N P K

Urban areas are the largest source of Turbidity Undisturbed Pasture Cultivated Rural residential Urban pervious Urban impervious TSS (kg ha -1 yr -1 )

Residence times are highly variableResidence times are highly variable Rivers have the longest residence timeRivers have the longest residence time Short residence times near inletsShort residence times near inlets Bramble Bay has the longest residence time within the bayBramble Bay has the longest residence time within the bay Residence time affects dilution of nutrients & sediments

Rivers receive inputs from a variety of point and non point sources Sewage Outfall Sewage Treatment Plant Industry Outfall Golf course fertiliser runoff and gravel extraction plant Grazing - manure Aquaculture Primary inputs are nutrients (nitrogen & phosphorus) and suspended solidsPrimary inputs are nutrients (nitrogen & phosphorus) and suspended solids

Degraded waterways stimulates study Concern about impacts of expanding populationConcern about impacts of expanding population Moreton Bay studyMoreton Bay study

“Moreton Bay and its waterways will, by 2020, be a healthy ecosystem supporting the livelihoods and lifestyles of residents and visitors”

STRATEGY RESEARCH MONITORING RiparianRehabilitation Sewage Treatment Upgrades Stormwater Quality Improvement Device To protect and restore waterways -

Monitoring & Research Essential tools for effective preservation and remediation of waterways Determines ecological outcomes of nutrient removal from sewage, stormwater controls and other management actions

Monitoring Ecosystem Health Indicators of Ecosystem Health loss or recovery of seagrasses, mangroves and corals

Monitoring Ecosystem Health Indicators of Ecosystem Health loss or recovery of seagrasses, mangroves and corals outbreaks of Lyngbya

Monitoring Ecosystem Health Indicators of Ecosystem Health loss or recovery of seagrasses, mangroves and corals outbreaks of Lyngbya the extent of sewage plumes

Monitoring Ecosystem Health Indicators of Ecosystem Health loss or recovery of seagrasses, mangroves and corals outbreaks of Lyngbya the extent of sewage plumes nutrient responses of phytoplankton communities

Monitoring Ecosystem Health Indicators of Ecosystem Health loss or recovery of seagrasses, mangroves and corals outbreaks of Lyngbya the extent of sewage plumes nutrient responses of phytoplankton communities occurrence of nuisance macroalgae e.g. sea lettuce

Monitoring Ecosystem Health Indicators of Ecosystem Health loss or recovery of seagrasses, mangroves and corals outbreaks of Lyngbya the extent of sewage plumes nutrient responses of phytoplankton communities occurrence of nuisance macroalgae e.g. sea lettuce status of turtles and dugongs

Monitoring Ecosystem Health Indicators of Ecosystem Health loss or recovery of seagrasses, mangroves and corals outbreaks of Lyngbya the extent of sewage plumes nutrient responses of phytoplankton communities occurrence of nuisance macroalgae e.g. sea lettuce status of turtles and dugongs water quality – –phytoplankton biomass – –nitrogen and phosphorus – –turbidity

Oxley Creek Oxley Creek drains an area of 260 km 2Oxley Creek drains an area of 260 km 2 It originates at Mt Perry south of Ipswich near Flinder’s PeakIt originates at Mt Perry south of Ipswich near Flinder’s Peak Variety of land usesVariety of land uses The catchment contains the endangered Angle- stemmed Myrtle (Austromyrtus gonoclada)The catchment contains the endangered Angle- stemmed Myrtle (Austromyrtus gonoclada)

Historically, Oxley Creek was cleaner “ …During summer holidays, as school boys, we had regularly swum and fished in the creek.”“ …During summer holidays, as school boys, we had regularly swum and fished in the creek.” “….in spawning times…. The mullet would jump out of the water…”“….in spawning times…. The mullet would jump out of the water…” “It was always muddy but not as bad as it is today.”“It was always muddy but not as bad as it is today.”

Oxley Creek is biologically important Fruit Bat Colony Wading Birds Dingo

Oxley Creek has recreational value Boats moored on creek Canoeing on Oxley Creek

Oxley Creek is Very Turbid Sand Extraction

Oxley Creek is Rich in Nutrients Inala STP Causing algal blooms downstream

Oxley Creek is Rich in Nutrients Oxley Creek receives nutrients from the influx of the Brisbane River Oxley Ck STP 2nd largest STP2nd largest STP

Impacts on Oxley Creek High faecal coliforms indicates contamination by faeces Low dissolved oxygen restricts aquatic life high

Community Involvement School students monitoring water quality Wetland restorationWetland restoration Weed eradicationWeed eradication Riparian regenerationRiparian regeneration Water quality monitoringWater quality monitoring Healthy riparian zone at upper Oxley Creek

River estuaries: moderately to highly degraded Pine River Brisbane River Logan River Bremer River Caboolture River Moderatedegradation Highdegradation Nutrients & sediments from forestry, agricultural and urban areasNutrients & sediments from forestry, agricultural and urban areas Algal booms, high nutrientsAlgal booms, high nutrients Nutrient uptake means no sewage nitrogen impact on Deception BayNutrient uptake means no sewage nitrogen impact on Deception Bay Urbanised & industrial catchmentUrbanised & industrial catchment High turbidity & nutrientsHigh turbidity & nutrients Urbanised & agricultural catchmentUrbanised & agricultural catchment Aquaculture prominentAquaculture prominent Very turbidVery turbid Highly turbidHighly turbid Extensive vegetation clearedExtensive vegetation cleared 10x more N10x more N Extremely degradedExtremely degraded Very high nutrient loadingsVery high nutrient loadings Too turbid for phytoplanktonToo turbid for phytoplankton Long residence timeLong residence time

Rivers are nutrient over-enriched High concentrations of nutrients often results in blooms of single species – reducing diversityHigh concentrations of nutrients often results in blooms of single species – reducing diversity Benthic microalgal bloom on Brisbane River sediment Jellyfish bloom in response to high plankton biomass in Pine River Aquatic weed bloom in upper Brisbane River Phytoplankton bloom in Caboolture River

River Estuaries Report Card 2000 NorthStradbrokeIsland Redcliffe BribieIsland MoretonIsland BrisbaneRiver LoganRiver PineRiver CabooltureRiver Caboolture River CWorsened Unchanged Improved A excellent B good C fair D poor F fail Pine Rivers D Brisbane River D Bremer River F Logan River D

River estuaries Moreton Bay Pristine and diverse marine environments Highly impacted river estuaries

Monitoring has identified zones of impacts Oxley Ck

Historically the Western Bay was relatively pristine Within Moreton Bay, dugongs, sea turtles and extensive seagrass beds were once present on the urbanised western shores, but are now largely restricted to the well flushed eastern regions.

What are the impacts on Moreton Bay? SedimentsSediments –50,000 truck loads of mud into Brisbane River every year NutrientsNutrients –500 olympic swimming pools of treated sewage effluent every day –1/3 Brisbane River flow is sewage effluent LyngbyaLyngbya –3000 football fields of seagrass covered by Lyngbya in Moreton Bay

Sewage Plume Mapping identifies zones of human impact Macroalgae takes up sewage nutrientsMacroalgae takes up sewage nutrients Chambers deployed around bay and riversChambers deployed around bay and rivers Allows mapping of extent of sewage plumeAllows mapping of extent of sewage plume

Plume mapping technique identifies different nutrient sources Highest sewage concentration is in middle reaches of the rivers due to inputs and lack of tidal flushingHighest sewage concentration is in middle reaches of the rivers due to inputs and lack of tidal flushing Plume concentrated in western bayPlume concentrated in western bay Sewage plume from rivers is seasonally variableSewage plume from rivers is seasonally variable September 1997 March 1998 June 2000

Monitoring affects management decisions

Sediments impact West Moreton Bay model output simulating May 96 flood

With sediments come nutrients % Mud Total N (mg L -1 )

Sediment re-suspension Bramble Bay Nearbed wave velocities (cm s -1 ) Water depth (m) Tide Wind February 3 January 27 January 20  wind waves and tidal currents

Suspended solids Seagrass distribution Sediments affect seagrass distribution

Reduced water clarity in Waterloo Bay due to river inputs and resuspensionReduced water clarity in Waterloo Bay due to river inputs and resuspension Last remaining healthy seagrass beds in Western Moreton BayLast remaining healthy seagrass beds in Western Moreton Bay Sensitive region with variable water qualitySensitive region with variable water quality

Seagrass loss has occurred due to Logan River plume Logan R First seagrass loss in 1992First seagrass loss in 1992 Recovery Recovery Disappeared since 1998Disappeared since 1998 Russell Is Macleay Is

Seagrass loss is ongoing Deception Bay (97)Deception Bay (97) Long Island (92, recover 98)Long Island (92, recover 98) Behm’s Creek (96)Behm’s Creek (96) Northern Broadwater (00)Northern Broadwater (00) Lyngbya majuscula bloomLyngbya majuscula bloom Loss reduces habitat

Are sediments affecting corals too? Scoping surveys shown dramatic shift from dead to live coral cover with distance from mainland in Waterloo BayScoping surveys shown dramatic shift from dead to live coral cover with distance from mainland in Waterloo Bay Intensive survey will be conducted each winterIntensive survey will be conducted each winter Favia speciosa. Waterloo Bay

Excessive nutrients cause algal blooms Ulva bloom Algal bloom 1000 ML per day

Bramble Bay is nutrient laden Phytoplankton blooms Mangroves full with nutrients Sediments release nutrients Mangroves Phytoplankton Phytoplankton levels

Lyngbya majuscula Toxic marine cyanobacterium Naturally occurring but proliferated in N. Deception Bay Bulldozers needed to remove rotting, stinking mass Human health problems Ecosystem health problems – seagrass loss, repels fish

Lyngbya has rapid growth

Lyngbya at Amity & Moreton Banks Occurs naturally on reefs and seagrass bedsOccurs naturally on reefs and seagrass beds Large amounts at Moreton / Amity Banks last summerLarge amounts at Moreton / Amity Banks last summer Potential threat to main dugong & turtle grazing areasPotential threat to main dugong & turtle grazing areas Less toxic than in Deception Bay, oyster impact unknownLess toxic than in Deception Bay, oyster impact unknown

Canal development Melaleuca Intact pine forest Cleared pine forest Soils samples collected from various sites in the Pumicestone Passage and Deception Bay region Sandstone Point Shirley Creek Mangrove Coffeerock

Clean, clear water No algal blooms Best in the Bay Eastern & Northern Moreton Bay

Eastern & Northern Moreton Bay B-/A Most pristine area of Moreton Bay extensive seagrass beds, mangroves, & coral reefs supporting huge diversity of marine life dugongs, turtles, whales, dolphins, fish Excellent water quality Tidal flushing – 1 day

Turtles and dugongs Dugongs and turtles now concentrated on Eastern side Dugongs Population ~ deaths since Jun 99 Turtles Population > 10,000 Green Turtle Fibropapilloma Disease 70% affected in S. Bay 40% affected in Peel Is. & reefs 20% affected at Moreton Banks

Eastern Banks Well-flushedWell-flushed Extensive seagrass beds supporting dugongs & turtlesExtensive seagrass beds supporting dugongs & turtles LyngbyaLyngbya B-B-B-B- Bramble Bay Bramble Bay Sewage inputsSewage inputs High nutrients and turbidityHigh nutrients and turbidity Ulva bloomsUlva blooms Historical seagrass lossHistorical seagrass loss High sediment nutrient fluxesHigh sediment nutrient fluxes F Waterloo Bay Some coralSome coral Stable seagrass bedsStable seagrass beds Stormwater controlStormwater control C+C+C+C+ Northern Deception Bay No improvement No improvement Declining seagrass Declining seagrass Lyngbya outbreak Lyngbya outbreak D-D-D-D- Southern Deception Bay No seagrass recoveryNo seagrass recovery High turbidityHigh turbidity D Southern Bay Extensive mangrove forestsExtensive mangrove forests Sewage inputsSewage inputs Seagrass lossesSeagrass losses Lack of mangrove recovery from hail damageLack of mangrove recovery from hail damage C-C-C-C- B Central Bay High sediment nutrientsHigh sediment nutrients Muddy sedimentsMuddy sediments Relatively good water qualityRelatively good water quality Northern Bay Well-flushed by oceanic watersWell-flushed by oceanic waters Intact denitrificationIntact denitrificationA Moreton Bay Report Card 2000 WorsenedUnchangedImproved A excellent B good C fair D poor F fail

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