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Re: Sulphur Affecting Mangroves

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Posted by CRMP on October 10, 1999 at 20:32:12:

In Reply to: Re: Sulphur Affecting Mangroves posted by Andrew Thor on September 30, 1999 at 16:28:23:

To make more specific recommendations, we need additional details, such as species used, age/height, and description of wilting or dieback and inundation, which are critical for diagnosis and prescription. Here are some general observations and recommendations:

1. Sulfuric acid is produced in mangrove areas with high organic matter under anaerobic conditions when the seawater containing sulfur is reduced to iron sulfide or pyrite (FeS /Fe S2) by sulfate-reducing bacteria through oxidation or exposure of the soil to sunlight, for example, when fishponds are drained. Sulfuric acid is toxic to plants and may cause seedling mortality.

2. mortality is not due to toxicity, it could be due to: a)root damage during the uprooting, hauling/transport of the wildlings and outplanting (damaged root systems cannot regulate salt absorption); b) inundation, the planting area may have lower elevation than the previous site

3. Sulfur oxide toxicity is common in a newly harvested mangrove where the debris is in the process of decomposition. It normally takes a year before replanting can be done.

4. If the site is inundated daily, the following species may be used: a) Rhizophora species -- may be directly sown/planted (propagules) or with potted seedlings; b) Avicennia marina -- may be directly sown or planted with potted seedlings; c) Sonneratia alba

5. If the site is inundated up to 10 days a month, then you can use more species that thrive in the middle and in the landward zone, such as A. officinalis, Ceriops, Bruguieras, Xylocarpus and the Lumnitzeras.


: Piwatter Council recently improved an area of Pittwater estuary by transporting sand & mud from an area in close proximity to batter a bank of a reserve on the edge of the bay. Transplanting of mangrove seedlings from the same site occured shortly after the sand and mud was rellocated.

: The sand and mud was possibly contaminated with pollutants from marine craft. All the seedlings have died. It has been suggested that an excess of sulphur was released when the sand & mud horizons were disturbed thus killing the seedlings and micro organisims.

: Does this sound like a feasable explanation and is it possible there is a solution to this problem.

: Please enlighten me with any suggestions you may have that may help regenerate the area.



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