Initial Transplant Field Tests

WPSP work on seagrasses began with early experiments undertaken by Dr Tim Ealey at Coronet Bay. The first experiment involved taking small sections of seagrass rhyzomes and transplanting them into an aquarium to determine the capacity of these plants to survive transplanting.  This work revealed that such transplants did in fact survive and grow and that wider application of this approach may be suitable for field application.

Test plantings in the field showed that small sections of seagrass could be transplanted but the wave and tide action meant many of these transplants were dislodged before they could establish themselves. This work indicated that larger clumps or plugs might offer a better alternative.

Busting Myths

Toxic Discharges

For several decades a local resident of Lang Lang made ongoing claims in the media that the seagrass losses in Western Port were caused by toxic discharges from ACI sandmine operations at Lang Lang. EPA Victoria investigated these claims thoroughly but no proof could be found to support the allegations and in any case the claim was inconsistent with losses observed elsewhere in the Bay.

Beach foam Lang Lang.

Seagrass grown in Lang Lang sediment (L) compared to seagrass grown in Coronet Bay sediment (R). Growth was clearly more prolific in the Lang Lang sediment.

Never-the-less, the claimant continued his accusations and further suggested that the mud around the Lang Lang coast was toxic and killed seagrasses. Dr Tim Ealey undertook several very simple experiments to show these claims were unfounded. Firstly he took samples of the Lang Lang mud and placed it in aquariums into which he planted seagrasses. These plants not only survived, but flourished, indicting quite clearly that the muds did not contain any substance toxic to seagrasses. Dr Ealey also obtained samples of the sump water and process water currently being used by ACI in their sandwashing operations. He introduced these samples into the aquaria at rates far higher than would be expected upon normal dilution in the bay, again with no adverse effect.

With these two simple experiments Dr Ealey had shown that the ACI operations were not currently impacting on seagrasses and if there were some lingering residues from previous operations, they too were not impacting on the seagrasses. PDF versions of these experimental reports can be downloaded here

Coastal Foams

A further claim against ACI sandmining was that its discharges included surfactants (detergents) that caused foams to form along the Lang Lang coastline from time to time. Samples collected from such events by the WPSP were supplied to EPA Victoria for testing and examination. Their conclusion was that these foams were entirely natural, the product of diatoms blooms and wind action, similar to those seen along surf beaches. The foaming in this section of the bay being amplified by the presence of fine silts associated with catchment and coastal erosion processes. Dr. Ealey’s bioassays of these foams showed that not only would they not stick to seagrasses as alleged but at several concentrations did not affect seagrass.

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