Archive for the 'Pacific Ocean' Category

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.

Good news from the Californian kelp forests

Published May 5, 2010 Coastal management , Kelp forests , Marine parks , Pacific Ocean Closed
At the beginning of May 2010 California’s underwater state park system in the U.S. was expanded. As a result, well-known north central coastal areas like Point Reyes Headlands, Bodega Head, the Farallon Islands, and Fitzgerald Marine Reserve are now more professionally protected than in the past. The measure is part of a new conservation regime, in which the state is creating a series of marine protected areas. They stretch from Point Arena to Pigeon Point.
The final result will be well-protected marine parks which are part of a statewide network. One of the key concepts is multiple use: new protected areas will not only restore sea life and habitats but also leave nearly 90 percent of the coast open for fishermen. The rebuilding of fisheries is included in the goals.

The giant kelp (Macrocystis pyrifera) seen in the background is the fastest growing plant on Earth.It grows more than 60 cm in length in 24 hours.Kelp is harvested in order to obtain alginic acid,an important ingredient of beer,icecream and cosmetic products. In the past coastal wastewaters led to population explosions of sea urchins.This harmed the kelp forests as sea urchins eat the holdfasts which anchor the kelp to the bottom. Photo from Santa Catalina Island, California, (c)2010 Erkki Siirila.

Kelp forests, canyons and reefs, where fish and shellfish feed and breed, are habitats of emphasis of the ocean conservation plan being applied. In many cases, the new sanctuaries, in which these habitats are located, are close to land-based parks. This facilitates their use for recreation and education.
Marine Life Protection Act (MLPA) requires the California state to develop a science-based system of marine protected areas. California is the first state in the U.S. to have this kind of comprehensive resource management plan. The latest implementation phases are important steps towards full statewide implementation by 2011. Local conservationists, divers, surfers, scientists, fishermen and business leaders take part in the process.
At the February 2010 Conference of American Association for the Advancement of Sciences several new marine protection studies were released. They confirmed the effectiveness of marine parks, mentioning success stories from the Channel Islands of California and the Great Barrier Reef of Australia. The studies show that ocean habitat protection benefits both fish and fishermen.
The new marine protected areas of California will be monitored by professionals.  Scientists will observe the ecological developments as part of the most ambitious study ever done of California’s coastal waters.  A great deal of work will be carried out underwater.

Tsunami hits Juan Fernández archipelago in Chile

Published February 28, 2010 Coastal management , Coastal risks , Pacific Ocean Closed

The powerful earthquake which hit Chile on 27 February, 2010, resulted in a tsunami.  Chilean coastal towns south of the capital Santiago suffered. In several communities the devastation was nearly complete.

The tsunami resulted in serious damage and lost lives also in the Juan Fernández archipelago, the home of Robinson Crusoe.  Eyewitness reports tell the megawaves caused destruction in places located 15 metres above the high-tide level. (Commonly tsunamis behave more like sudden and extreme high tides than normal waves.)

Sad events like these emphasise the importance of sound management of the coastal zone.  Wise people are proactive, while the less wise are reactive and pay a higher price: a well known fact in coastal risk management is that prevention costs less than reparation.

The wise never forget the power of the sea. Photo (c) 2010 Erkki Siirila.

In Chile, the government is aware that earthquakes are part of life. The Chileans cannot be critised for the lack of preparedness.

In any case, the first pictures taken after the earthquake in Juan Fernández in the Pacific Ocean show the power of tsunamis.  Lessons in coastal management can be learned by looking at the photos.

Wide construction-free zones on oceanic shores are one solution. Improving the tsunami warning systems would be another. Also better construction practices, which take into consideration the forces of nature, help minimise the damage.

Most of the people who suffered from the tsunami in Chile were not warned because of misunderstandings between authorities and hesitation during the crucial moments. Radio news had even transmitted messages telling there was no tsunami risk.

It is also possible that many people did not remember the simple safety rule the Chilean authorities use when they inform of precautionary measures: If you cannot keep your balance while experiencing an earthquake on the coast, the earthquake is so strong that it can produce a tsunami.  You should immediately escape.

The link to the first Chilean tsunami images, which are from Juan Fernández, is here:

Tsunami damage in the Juan Fernández archipelago, Chile  (Sorry, the photographer has removed the pictures from Flickr. This direct link is not working any more.)

Alarming coral news from Australia

Published December 14, 2009 Climate change , Coral reefs , Pacific Ocean Closed

Science presented in January 2009 alarming news on the challenges facing coral reefs.  In a scientific article Glenn De’ath, Janice M. Lough and Katharina E. Fabricius summarised the evidence from 69 reefs in the Great Barrier Reef of Australia.  According to that study reef-building corals are under increasing physiological pressure from a changing climate and ocean absorption of increasing atmospheric CO2.

The calcification rate in the studied areas had diminished by 14.2% since 1990.  This kind of drop in calcification is “unprecedented in at least the past 400 years”.

The authors suggest that temperature stress and declining saturation state of seawater aragonite are diminishing the ability of the Great Barrier Reef corals to deposit calcium carbonate.  If this is really happening, the physical structure of the reefs is in danger to erode away and the whole coral reef ecosystem can be considered endangered.

Professor Ove Hoegh-Guldberg from the University of Queensland has presented similar alarming indications of the threats to coral reefs.  He highlighted the dangers of  the increasing atmospheric CO2 levels to coral reefs at the U.S. Center, Copenhagen, in December 2009.  This is the link to the video summary of his presentation: