How Healthy is Moreton Bay?

1. How Healthy is Moreton Bay? CRC for Coastal Zone Estuary & Waterway Management • Ivan Holland, Francis Pantus, Andrew Watkinson, Dan Wruck & • Bill Dennison Adrian Jones & Angela Grice

2. EHMP Project Team CRC for Coastal Zone Estuary & Waterway Management Angela Grice Ivan Holland Paul Lutz Andrew Moss Mark Davidson John Ferris Michelle Leutton Myles Waller Ray Clark Darren Renouf Chris Ovenden Nathan Johnston Phil Thornton Nicola Udy Bill Dennison Adrian Jones Courtney Henderson Volunteers Francis Pantus Peter Toscas Tom Taranto Dan Wruck

3. Presentation Outline • Introduction to Moreton Bay and its Rivers • Historical conditions • Current pressures on the ecosystem • The Vision for the future • Monitoring ecosystem health • Wastewater treatment initiatives • Health of the Rivers • Health of Moreton Bay • Sediments • Nutrients • Lyngbya • Future Strategies, Research & Communication

4. Moreton Bay is a productive coastal embayment • Moreton Bay shows relatively high concentrations of phytoplankton and suspended solids Moreton Bay

5. Moreton Bay Bribie Island • Moreton region has 2 million people and is the fastest growing region in the country • Moreton Bay receives input from Brisbane, Logan, Caboolture and Pine Rivers • The Brisbane River has the • largest catchment of all regions • highest population density • highest sewage inputs Caboolture River Moreton Island Redcliffe Pine River Luggage Point Dunwich Brisbane River Logan River

6. Brisbane River has the largest catchment Great Dividing Range Brisbane River Catchment Logan River Catchment Pine Rivers Catchment Caboolture River Catchment • Brisbane R. catchment extends to Great Dividing Range • Includes 4 major subcatchments • Upper Brisbane, • Stanley • Lockyer • Bremer

7. Residence time affects the dilution of nutrients discharged into the waterways • Residence times are highly variable • Rivers have the longest residence time • Short residence times near inlets • Bramble Bay has the longest residence time within the bay

8. The river estuaries are BROWN iological diversity low esuspended Brown ver-loaded aste water utrient laden

9. Moreton Bay is BLUE iological diversity high Blue ow nutrients nimpacted nergetic

10. Historically, the rivers were cleaner Swimming enclosure at East Brisbane Aug 1918 July 1917 Oct 1997 Moreton Bay Colleges Crossing 250 Turbidity 200 150 0 10 20 30 40 100 50 0 Jewfish caught in Brisbane River • Historically, the rivers had: • much lower inputs ofsewage and catchment runoff • extensive vegetation on river banks • water clarity was much better • large fish such as cod, black swans and aquatic plants existed in Brisbane River

11. 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.

12. Population Growth is a major pressure 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

13. Increasing land-use Sown pasture Cropped land 300 Land area 000’s ha 200 and fertilizer application 100 1860 1900 1940 1980 20 N P 15 K 10 Fertilizer 000’s t yr-1 5 1910 1950 1990

14. 1000 800 600 400 200 0 Pasture Cultivated Undisturbed Urban pervious Rural residential Urban impervious Urban areas are the largest source of Turbidity TSS (kg ha-1 yr-1)

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

16. Multiple sewage discharges in region stimulated large regional study • Concern about expanding population and impacts of sewage discharges • 6 local councils formed regional study group, obtained commonwealth & state matching funds • 1997-1998 large intensive study conducted • Developed Vision & monitoring strategy

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

18. Monitoring is an essential tool for effective preservation & remediation of waterways • Research and monitoring provides the information to determine the most effective remediation options • It determines the ecological outcomes of nutrient removal from sewage, stormwater controls and other management actions

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

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

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

22. 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

23. 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

24. 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

25. 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

26. Sewage Plume Mapping identifies zones of human impact • Macroalgae takes up sewage nutrients • Chambers deployed around bay and rivers • Allows mapping of extent of sewage plume

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

28. Monitoring affects management decisions

29. Monitoring has identified zones

30. River estuaries: moderately to highly degraded Pine River Moderate degradation • Nutrients & sediments from forestry, agricultural and urban areas • Algal booms, high nutrients • Nutrient uptake means no sewage nitrogen impact on Deception Bay • Urbanised & industrial catchment • High turbidity & nutrients High degradation Caboolture River • High sediment & nutrient loads • Extensive vegetation cleared • Low plankton species diversity • Extremely degraded • Very high nutrient loadings • High bacterial productivity • Long residence time • Urbanised & agricultural catchment • Aquaculture prominent Logan River Bremer River Brisbane River

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

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

33. Rivers used for commercial and recreational purposes Trawling in Brisbane R Fishing at Luggage Pt Outfall Port of Brisbane Skiing in rivers Swimming in rivers

34. River Estuaries Report Card 2000 Bribie Island Caboolture River Moreton Island C Caboolture River Redcliffe D Pine Rivers Pine River Luggage Point D Brisbane River Dunwich Brisbane River F Bremer River D Logan River Logan River Worsened Unchanged Improved A excellent B good C fair D poor F fail

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

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

37. Sediments impact West Moreton Bay model output simulating May 96 flood

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

39. wind waves and tidal currents 40 30 Wind Nearbed wave velocities (cm s-1) 20 Tide 10 0 8.5 7.5 Water depth (m) 6.5 5.5 January 20 January 27 February 3 Sediment re-suspensionBramble Bay

40. Sediments affect seagrass distribution Suspended solids Seagrass distribution

41. Sediments affect seagrass distribution • Reduced water clarity in Waterloo Bay due to river inputs and resuspension • Last remaining healthy seagrass beds in Western Moreton Bay • Sensitive region with variable water quality

42. Seagrass loss has occurreddue to Logan River plume • First seagrass loss in 1992 • Recovery 1994-1998 • Disappeared since 1998 Macleay Is Russell Is Logan R 1989 1996

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

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

45. Excessive nutrients cause algal blooms Ulva bloom 1000 ML per day Algalbloom

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

47. 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

48. Lyngbya has rapid growth

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

50. Lyngbyaat Amity & Moreton Banks • Occurs naturally on reefs and seagrass beds • Large amounts at Moreton / Amity Banks last summer • Potential threat to main dugong & turtle grazing areas • Less toxic than in Deception Bay, oyster impact unknown