Marine Pollution & Turtle Death

When Lyngbya is in bloom, it can cause problems for the natural environment as well as human health. The effects of these blooms include:

Environmental

• • Seagrass die-back, due to shading and smothering of seagrass by the Lyngbya bloom.

• • Smothering of mangrove aerial roots and seedlings.

• • Disturbance to animal populations, including dugongs, turtles, fish and macroinvertebrates such as crabs and shellfish.

• • A decline in water quality, including lowered levels of dissolved oxygen and increased sediment nitrogen levels.

Human health

• • Skin irritations such as dermatitis and / or respiratory disorders and eye irritations brought about through physical contact with

• • Lyngbya or breathing in airborne toxins produced by Lyngbya in its dry state.

• • Pungent smells from the degradation of the Lyngbya when decomposition occurs on the beaches.

Economic

• • Temporary beach closures affecting the tourism industry.

• • Large clean-up bills for local councils.

• • Dramatic effects on the commercial fishing industry.

Lyngbya exists in warm tropical and subtropical estuarine and coastal marine waters around the world. Lyngbya blooms have been reported in such areas as Hawaii, Mozambique, Philippines and Curacao. In Australia Lyngbya occurs in South Western Australia and in Queensland on the Great Barrier Reef, in Hervey Bay and South East Queensland.

Given the right conditions, Lyngbya can grow excessively or ‘bloom’, with some blooms known to stretch over kilometres. Lyngbya blooms are normally found growing attached to seagrass, seaweed and other aquatic surfaces like coral and rocks. Lyngbya can also be found floating in the water and washed up on beaches.

The cause of Lyngbya blooms in South East Queensland is complex and it is likely that no one factor alone triggers bloom events. Increased nutrients (phosphorus, nitrogen and iron) and dissolved organic matter have been shown to provide optimal growth conditions for Lyngbya especially during summer when light conditions and water temperatures (about 24°C) are favourable.

In Moreton Bay, Lyngbya blooms tend to occur in October lasting through to mid-February and decreasing in extent from April to May. In Deception Bay, blooms commonly start in November and extend through to February and March.

Avoid contact with Lyngbya in the water or on the beach. If contact with Lyngbya occurs, rinse the area with fresh water as soon as possible. If you experience stinging, burning or itching sensations or respiratory discomfort after contact, seek medical attention.

Lyngbya will always exist to some extent as it is a natural component of our estuarine and coastal marine systems. State and local governments regularly monitor blooms and have contingency response plans to minimise the impact of Lyngbya blooms on public health and the community.

To reduce Lyngbya outbreaks and minimise their effects in South East Queensland, the Coastal Algal Blooms Action Plan within the SEQ Healthy Waterways Strategy 2007–2012 outlines a cooperative approach involving the SEQ Healthy Waterways Partnership Office, researchers, all levels of government, industry and the wider community. Legislative strategies to minimise the movement of nutrients from the land into coastal waters (where they can stimulate blooms) are addressed in the South East Queensland Regional Coastal Management Plan and South East Queensland Regional Plan 2009-2031. However, it will take time before implementation of these management strategies lead to a reduction in the frequency or severity of bloom outbreaks.

• • Know how to identify Lyngbya and report sightings to the Redland City Council.

• • Reduce fertiliser use. This will reduce nutrients entering waterways.

• • Keep streets and stormwater drains free of green wastes.

• • Help restore riparian (riverbank) vegetation as it will improve the quality of water entering waterways.

[Ref. Queensland Government Department of Environment & Heritage Protection Algae and algae blooms]