Coasts & Estuaries - City of Port Adelaide Enfield - SA.Gov.au

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Coast & EstuariesGood (for all samples taken)2 Poor (number indicates how many samples had poor result)Not monitored6 Snapshot Events per year in March, May, June, Aug, Sept, Oct/Nov. Not all groups will havemonitored every Snapshot event in every year.Results RatingTurbidity: Good < 5 NTU; Poor > 25 NTUNitrate: Good < 1 mg/L N; Poor = or > 1 mg/L NOrtho Phosphate: Good < 0.1 mg/L P; Poor > 1 mg/L PpH: Good pH 6.5-9.2; Poor < 6.5 > 9.2Ammonium: Good < 0.5 mg/L; Poor > 0.5 mg/LAlkalinity: Good 90-120mg/L calcium carbonate; Poor 120 mg/L• A higher incidence of poor samples were recorded from the Port Adelaide River, Hack St outfallwith a total of 19 poor samples, followed by the Port Adelaide River, waste water outlet andMangrove Cove with 16 poor samples each during the sampling period.• Very high levels of nitrate and phosphate were recorded at several locations in 2003 and 2004indicating a local source of nutrients entering the estuarine system.Sample Location: POR020, Mangrove CoveSource: KESAB Waterwatch: http://www.cwmb.sa.gov.au/kwc/programs/water_monitoring.htmImpacts on Marine EcologiesThe EPA have noted a serious and continuing decline in the marine ecosystems in the region,particularly in the loss of seagrasses and mangroves. Nutrient levels especially nitrogen, isconsidered to be a principle factor in the ecosystem design. Development and industrial land use isalso an important contributing factor in changes to the distribution of biological communities in thePort waterways (EPA, 2005).Mangroves, Seagrass and SaltmarshThe seagrass, mangroves and saltmarsh of the Port Adelaide River have been degraded over time bypollution (particularly effluent outfall) and development.142
Coast & EstuariesPressure Indicator: Ecosystem decline of mangroves, seagrasses and saltmarsh (by %)Figure 24 depicts the ecosystem decline showing the condition of mangroves, seagrasses andsaltmarsh.There has been extensive loss of seagrasses in the northern part of the Port Adelaide River environs(north of Outer Harbor) due to effluent outfall and nutrient enrichment of the waters, it is estimatedthat since 1954 approximately 36.4% of the subtidal seagrasses have been lost, much greater thanexpected from natural changes. This subsequently has detrimental impacts on fish nurseries. Inaddition since 1954 it is estimated that approximately 25% of mangroves and 80% of samphires havebeen lost due to development (Kinhill Sterns, 1985).Monitoring has indicated that the growth of the weed Ulva (large nutrient-induced epidphytes) hascaused death rates of young mangrove seedlings of 67% (significantly greater than occurs naturally).Recognition of the ecological value of mangroves and seagrasses has taken precedence over that ofsaltmarshes, with little scientific work available on South Australian saltmarshes resulting in 80% ofthis habitat being lost in the Barker Inlet-Port Adelaide River region.Caulerpa taxifoliaCaulerpa taxifolia is a pest weed that has colonised in the waters of West Lakes and Port AdelaideRiver. A significant concern is the potential spread of the weed as a result of the ample nutrientsupply. It was first discovered in West Lakes in 2002, and was successfully removed by fresh waterflushing of the lakes.The weed was also discovered in the Port Adelaide River, and attempts have been made to eradicatethe weed using salt, chlorination and suction. Despite this, colonisation has occurred around GardenIsland into Eastern Passage, North Arm and the southern end of Barker Inlet. The further spread ofthis weed has been attributed to the 2004/05 long hot summer and mild start to winter.Caulerpa taxifolia is a bright green seaweed with main stems that can grow up to three metres longwith up to 200 fronds growing off these stems that look like feathers or ferns. It can grow up to 25mma day and spreads by itself. New infestations start by dispersion of tiny plant fragments and are alsothought to spread via the release of spores. Caulerpa is a tropical species and its ideal habitat iswarmer waters, but the strain invading the Port Adelaide River is capable of surviving and thriving innon-tropical waters. Anchoring of vessels helps to spread the weed.Caulerpa taxifolia spreads quickly over the sea floor and takes over areas of native species such asseagrass. It is a very real threat to the seagrass meadows of Gulf St Vincent . When it takes overthis flora, it destroys fish nurseries and fish habitat. Fish do not eat Caulerpa taxifolia because itcontains a toxin that is distasteful to them.PIRSA and SARDI Aquatic Sciences are continuing to monitor and attempt to manage and eradicateCaulerpa taxifolia in the Port Adelaide River. This includes divers controlling high risk areas, anddeveloping dredging plans. There is currently in force a ban on anchoring in most of the PortAdelaide River to prevent spread of the weed, the ban exists from snapper point (Outer Harbor)running the length of the Port Adelaide River and up to the middle ground beacon (Inner) of theBarker Inlet/Torrens Reach.143
Page 1 and 2: City of Port Adelaide EnfieldState
Page 3 and 4: Coast & EstuariesBarker Inlet & Por
Page 5 and 6: Coast & EstuariesWater QualityThe w
Page 7 and 8: Coast & EstuariesFigure 22: Port Ad
Page 9 and 10: Coast & EstuariesNutrient loads - N
Page 11: Coast & EstuariesState Indicator: R
Page 15 and 16: Coast & EstuariesFigure 25: Caulerp
Page 17 and 18: Coast & EstuariesFigure 26: Map of
Page 19 and 20: Coast & EstuariesWithin the Port Ad
Page 21 and 22: Coast & EstuariesA working PortThe
Page 23 and 24: Coast & EstuariesGulf St Vincent &
Page 26 and 27: Coast & EstuariesFigure 27: Map of
Page 28 and 29: Coast & EstuariesOne of the major i
Page 30 and 31: Coast & EstuariesTable 31: Amount o
Page 32 and 33: Coast & EstuariesReferencesACWS Tec
Page 34 and 35: Figure 28: Port Adelaide River-Bark

Coasts & Estuaries - City of Port Adelaide Enfield - SA.Gov.au

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