Archive for the 'Environmental impacts' Category

Human wastewaters infect elkhorn coral

Published September 20, 2011 Caribbean Sea , Coastal management , Coral reefs , Environmental impacts , Pollution Closed

A human pathogen has been shown to contribute to the degradation of elkhorn coral (Acropora palmata) colonies in the Caribbean Sea. The pathogen Serratia marcescens is known to be present in human wastewaters, which enter the coastal marine areas untreated in many parts of the Caribbean. In the recent study by K.R. Sutherland et al., strain PDR60 of the pathogen was shown to cause disease signs in A. palmata colonies in as little as four or five days, when the surrounding waters were polluted with S. marcescens.

In the Caribbean the lack of wastewater treatment is a common problem. This colony of elkhorn coral looks healthy in spite of the fact that raw sewage enters the sea 100m from the reef. Photo taken in Utila, Honduras, copyright (c) 2011 Erkki Siirila.

In 2003 there was an outbreak of this coral disease called acroporid serratiosis (APS). During the episode, the corallivorous snail Coralliophila abbreviata and stony coral Sideastrea siderea were noticed to be play a role in the development of the disease. Now, in aquaria experiments, wastewater has been demonstrated to be a definitive, direct source of the disease, while C. abbreviata and S. siderea are known to act as vectors and reservoirs, which may also to contribute to the infection of A. palmata.

The research results by K.R.Sutherland et al. published in 2011 demonstrate for the first time that a human pathogen can be passed from us humans to marine invertebrates and infect them. The authors of the study “Human Pathogen Shown to Cause Disease in the Threatened Eklhorn Coral Acropora palmata” say that “these findings underscore the interaction between public health practices and environmental health indices such as coral reef survival”.

A direct link to the article is here:  Elkhorn and sewage

Coastal zone of Chile: ten management recommendations

Published August 14, 2011 Coastal management , Coastal risks , Emergency preparedness , Environmental impacts , Environmental policy , Human development , Marine parks Closed

Chile is a country with thousands of kilometres of coastline (the exact length of the coast depends on the definition applied). Naturally, moving towards integrated coastal zone management benefits a country like that.

The Coastal Challenges editor did a consultancy in the Fourth Region (Coquimbo Region) of Chile a few years ago. One of the results was a set of general guidelines for integrated coastal management in that region. In the ten conclusions/recommendations the local experiences were combined with the lessons learned in coastal management internationally.

A powerful tsunami in 2010 made Chileans aware of the need for sound coastal management. This Chilean government fax indicating there was a tsunami risk was not enough to result in massive coastal evacuations. As a result, lots of human lives were lost.

The conclusions and recommendations for integrated management of the Coquimbo coastal area are listed below:

  1. Integrated management of the coastal zone is a learning process with incremental implementation, feedback and adjustment mechanisms.
  2. At all levels of action, it is important to build the integrated management on a sustainable  financial and economic base, for example through self-funding.
  3. It is important to incorporate in the process the opinions of all the involved and interested parties, for example by applying conflict resolution mechanisms.
  4. It is essential that the actions keep focus on just a few issues which are understood by all the participants in the process. The focus on the issues means that an exact definition of the coastal zone is not a precondition for the action to begin.
  5. In general, construction on the local institutional roots is the safest option. E.g. the existing management systems, which are politically supported, can be modified instead of building totally new management institutions. Also in this case, the application of innovative ideas for real integration is important.
  6. A long-term vision is essential, and as part of this, opportunities should be left open for the future generations.
  7. The management should be based on good knowledge of the laws of nature. Implementation would need to be proactive instead of retroactive.
  8. It is important that the decision-making system is just and efficient.
  9. It is essential to understand that combining sustainable management with the poverty of resource users is difficult. Because of this, development of economic alternatives for the least favoured groups is needed.
  10. In sustainable coastal zone management, integration mechanisms are only one element. Specific action is needed also in the management of key species and habitats, pollution control, land use planning and environmental impact assessment. In addition to integration, sectoral activities in these and other action fields need to continue. (Naturally, sector-specific work needs to go on, but the sectoral actions should no more be implemented in isolation from other coastal zone activities.)

Revolutionary method: gypsum controls runoff

Published January 6, 2011 Baltic Sea , Coastal management , Coral reefs , Ecosystem restoration , Environmental impacts , Eutrophication , Sediment control Closed

An interesting discovery is helping in Baltic Sea conservation efforts in Finland. It involves the use a gypsum, which is a chemical substance known to most of us.

The environmental challenge we are talking about is that phosphorus, an essential plant nutrient, is transported from the farming fields through runoff into the rivers and sea. In the sea water, elevated levels of phosphorus cause eutrophication.

Yara, a chemical company, has together with a few Finnish partners developed a gypsum-based technique to stabilize soil particles in the farming fields. The method reduces soil (and nutrient) erosion caused by surface runoff.

The results achieved indicate that a high percentage of the phosphorus stays in the soil when the new technique is used. Consequently, harmful nutrient inputs into the waterways and sea are highly reduced. The new method also helps the farmer as more phosphorus is available for the agricultural plants. Furthermore, there is less need for costly, additional phosphorus fertilizers.

In spite of not being visible in this image, eutrophication caused by excessive nutrients is a problem on the Baltic coast of Finland. Photo (c) 2010 Erkki Siirila.

The method involves spreading of a gypsum-based product on the farming field after harvest or before planting. The product, which is basically gypsum (calcium sulphate), infiltrates with water into soil. According Yara, this well-known chemical compound in its slightly developed form improves “particle aggregation and dissolved phosphorus retention”. In addition, “better soil structure means that the earth resists rain and melting snow better and therefore prevents erosion and phosphorus leakage”.

Gypsum is useful to the farmer also because it improves the plants’ ability to utilise the phosphorus reserves of the soil. In addition, farmers can continue their agricultural activities as before. For the gypsum treatment to be effective, it would need to be repeated once in three to four years.

Gypsum treatment of the soil could be important news for many countries. Soil,sediment and nutrient runoff is degrading forestry and agricultural areas around the world. This runoff is also killing shallow marine ecosystems. Could gypsum help save the world’s endangered coral reefs?

A brochure on the gypsum-based method to control agricultural runoff into the sea can be found here:

http://orgprints.org/16037/1/Pietola.pdf

Alarming coral death on South-East Asian reefs

Published October 30, 2010 Climate change , Coral reefs , Environmental impacts , Indian Ocean , Pacific Ocean Closed

“It is certainly the worst coral die-off we have seen since 1998. It may prove to be the worst such event known to science,” says Dr. Andrew Baird, an Australian coral reef specialist in an interview by Underwatertimes.com published on 18 October, 2010.

Dr. Baird estimates that approximately 80% of Acropora coral colonies and 50% of colonies by other species have died during the past six months on the bleached coral reefs in the Indian and Pacific Oceans.

Healthy-looking and bleached coral side by side. Photo (c) 2010 Erkki Siirila.

The reefs are numerous: the mass bleaching affects an area which extends from the Seychelles to Sulawesi and the Philippines. Included are reefs in Sri Lanka, Burma, Thailand, Malaysia, Singapore, and Indonesia.  The most diverse reefs of the world are found in the so-called “Coral Triangle” which is within the affected area.

In the Underwatertimes article Dr Baird comments the seriousness of the situation by stating that the live percentage coral cover on the reefs could drop from 50% to about 10% (these are average values).  The recovery, if it ever occurs, will take years.  Fisheries and tourism in the affected coastal and island nations will suffer: the livelihoods of millions of people are likely to be hampered.

The bleaching is being caused by elevated mean seawater temperatures which result in the loss of symbiotic microalgae from the coral tissues. As the pigments are in the algae, the coral colony turns white. When the seawater temperature stays higher than normal for weeks, the bleached coral colonies often die – for nutrition the coral depends on the algae.

The warming of seawater to levels which are higher than normal is related to the planet-wide effects of the periodic El Niño and La Niña weather disturbances, which in turn seem to be getting more extreme with global climate change.

In non-scientific terms the recent events in South-East Asia could perhaps be summarised by stating that “the rainforests of the sea are dying”.  People who have seen a healthy coral reef might also use the expression “a very sad and serious ecological disaster is taking place”.

Coral builds impressive living structures in the tropical oceans. Climate change, seawater warming and coral bleaching may kill these underwater cities. Photo from Hurghada,Egypt, copyright (c) 2010 Erkki Siirila.