Archive for the 'Climate change' Category

Extensive coral bleaching is destroying reefs

According to the National Oceanic and Atmospheric Administration (NOAA) of the U.S., the longest coral bleaching ever is occurring in the tropical seas. The on-going, especially strong El Niño is prolonging the event, which started in 2014 and which is likely to lead to a wide-spread die-off of reef corals around the world. The scientists of NOAA expect the bleaching to continue in 2016 and 2017. So far, the Caribbean, Indian Ocean and Pacific Ocean have been affected.

The current bleaching is a serious environmental accident not only for all of us fascinated by the oceans, but especially for those 500 million people whose survival depends on the reefs. Fish species important for human consumption live in the coral communities. In addition to provision of food, the reefs also protect the islands and coastal areas from erosion and other damage caused by powerful waves.

Partly bleached coral colony in Saint Lucia. Copyright (c) 2016 Erkki Siirila.

Partly bleached coral colony in Saint Lucia. Copyright (c) 2016 Erkki Siirila.

Coral reefs are also key habitats for marine biodiversity and, related to that, increasingly important for underwater tourism. NOAA estimates the positive annual contribution of coral reefs to world economies to be about 30,000 million US dollars.

When corals get stressed by elevated seawater temperatures, they expel their zooxanthellae, the microscopic algae living in their tissues. As the pigment is in the algae, the corals lose their typical color. Bleaching is a serious occurrence, because without their symbiotic zooxanthellae the corals are starving as the microscopic algae are a significant food source. The bleached corals also become attacked by diseases more easily than before.

In case the average water temperature continues at levels higher than normal for several days, the corals can not recover their symbiotic algae and may die. When the colonies die, erosion starts eating reef structures away. A high percentage of the coral area may be lost for ever if a new bleaching hits the reef within a few years, i.e. when there has been too little time for recovery. As in many cases there are also other environmental stress factors (overfishing, sediment runoff, etc.) present, in today’s world, complete recovery is often impossible.

The first serious global bleaching in history occurred in 1998. The second one occurred in 2010. Like in the current third one, the El Niño / La Niña phenomenon is seen as the main underlying course (via elevated mean sea water temperatures). Global climate change is considered as a significative contributing factor behind the exceptionally strong El Niño and La Niña weather changes.

WWF Living Blue Planet Report: alarming 49% decline in marine animals since 1970

An incredibly serious decline of 49% has taken place in the numbers of marine animals between 1970 and 2012. This is one of the main results of an updated study of marine mammals, birds, reptiles and fish published in September 2015. WWF Living Blue Planet report is based on research results summarised by the Zoological Society of London. Overall, 5,829 populations of 1,234 species were studied.

Mangroves and sea grasses of Utila, Honduras. Photo and copyright (c) 2015 Erkki Siirila.

Mangroves and sea grasses of Utila, Honduras. Photo and copyright (c) 2015 Erkki Siirila.

Not only numbers of marine vertebrate species have plummeted, also the increasing decline of marine habitats is alarming. The deforestation rate of mangroves, which offer many on-site and off-site ecological and economic benefits, has been 19% between 1980 and 2005. Equally important wetland areas the world’s seagrass habitats have lost about 30% of their total area since 1879. Seagrasses are important carbon sinks in the shallows waters of the seas.

As regards coral reefs, where 25% of all marine species can be encountered, their live coral cover has decreased by more than 50% during the past 30 years. In addition, there has been a 34% decline in reef fish populations between 1979 and 2010. The report says that due to climate change (ocean warming and acidification), the live cover of coral reefs could practically be lost across the globe by 2050 – at least as regards the main reef component the stony corals, which are the main reef builders.

Healthy coral reef off Roatan, Honduras. Photo and copyright (c) 2015 Erkki Siirila.

Healthy coral reef off Roatan, Honduras. Photo and copyright (c) 2015 Erkki Siirila.

Regarding fish stocks (930 species and 1463 populations studied) there has been a 50% reduction in population numbers around the globe between 1970 and 2010. 29% of commercial fish stock are considered as overexploited. 61% of the stocks are classed as fully exploited.

As to such important food fish as mackerels, tuna, bonitos and their relatives in the Scombridae family, there has been a 74% decline between 1970 and 2010. Also sharks, rays and skates are facing survival threats: global catches have increased dramatically and 25% of the populations are threatened by local extinction.

Bottom trawling is in difficulties as well: There has been a 72% decrease in catches during the last 40 years. As to deep sea trawling specifically, this practice can be considered mostly unsustainable.

Fishing vessel in Mar del Plata, Argentina. Photo and copyright (c) 2015 Erkki Siirila.

Fishing vessel in Mar del Plata, Argentina. Photo and copyright (c) 2015 Erkki Siirila.

Of the four marine turtle species facing survival threats, the leatherback is having the biggest problems with 4 of the 7 sub-populations critically endangered.

Living Blue Planet Report indicates that also seabird and shorebird populations commonly face threats. The same is true for pinnipeds (seals, sea lions, sea elephants and walruses). Other marine mammal populations (whales & dolphins) and sirenians (manatees & dugongs) were not assessed in detail in this study – the information of their population development is considered data deficient. Also most marine invertebrates belong to the same “data deficient” category and detailed information regarding their conservation status is not available.

One of the press releases presenting the report summarises the findings of Living Blue Planet in the following words:

“As well as being disastrous for ecosystems, these findings spell trouble for all nations, especially people in the developing world who depend heavily on the ocean resources.”

“While over-exploitation is identified as the major threat to ocean biodiversity, the study finds that climate change is causing the ocean to change more rapidly than at any other point in millions of years. Rising temperatures and increasing acidity levels caused by carbon dioxide are further weakening a system that is already severely degraded through overfishing, habitat degradation and pollution.”

“By over-exploiting fisheries, degrading coastal habitats and not addressing global warming, we are sowing the seeds of ecological and economic catastrophe.”

“But there are clear steps that all governments can take to restore our oceans.  Creating networks of well-managed marine protected areas is a proven way to enable wildlife and habitats to recover. Pushing for a strong global deal on climate change would help the seas sustain life far into the future.”

Living Blue Planet Report 2015 can be downloaded from these two web sites:

NASA: sea level rising faster than the UN predicted

Recently published research indicates that sea level rise is a bigger threat to us and our coastal regions than previously thought. The latest predictions were made public by a team of Nasa-related scientists in August 2015. This is a summary of the most recent views:

  • The global estimate before the new figures was that of experts associated with the UN. In 2013 a UN panel predicted that sea levels would rise from between 0.3 and 0.9 metres by the year 2100. The latest Nasa research indicates that the lower figures are likely to be unrealistic and the higher estimates for the year 2100 are the correct ones.
  • According to a comment made to CNN by Steven Nerem, a researcher based at the University of Colorado, the planet is “locked into at least 3 feet (nearly 1 metre) of sea level rise, and probably more”.
  • The changes differ from region to region. Based on satellite data, in some areas like the US west coast, sea levels have not been rising but actually falling in recent years. Natural cycles and ocean currents are likely to be behind the phenomenon in these areas of the Pacific. Nevertheless, a substantial sea level rise may take place on the US west coast in the coming 20 years.
Ice and glaciers in Greenland. In case all the ice here melts, we will have big problems in our coastal areas. Photographer and copyright (c) 2015 Erkki Siirila.

Ice and glaciers in Greenland. In case all the ice here melts, we will have big problems in our coastal areas. Photographer and copyright (c) 2015 Erkki Siirila.

  • On a global scale, low-lying regions (such as Kiribati, Bangladesh, the Maldives and Florida in the US) are the most vulnerable land areas.
  • The rule of thumb is that for every centimetre of sea level rise, the sea moves 50-100 centimetres inland (source NASA).
  • The most difficult question in forecasting is determining at what rate the polar ice sheets will melt when temperatures on the planet go up.
  • Approximately one-third of the sea level rise is due to the thinning and loss of the Greenland and Antarctic ice sheets, another third is caused by the expansion of ocean water, and the remaining third is a consequence of the melting of mountain glaciers.
  • The latest data, gathered by satellites, reveal that sea levels have risen nearly 7.5 centimetres since 1992.

Seas, coasts and climate change negotiations

In 2015 the countries of the world will hopefully agree on a binding climate treaty in Paris. The outcome should stop climate change, which is currently threatening the wellbeing of the inhabitants of this planet.

What are the threats facing the coastal area and the marine systems? The answer to this question was presented in the Summary for policymakers of the Intergovernmental Panel on Climate Change (IPCC) in 2014.

Coastal systems and low-lying areas

Due to sea level rise projected throughout the 21st century and beyond, coastal systems and low-lying areas will increasingly experience adverse impacts such as submergence, coastal flooding, and coastal erosion (very high confidence).

The population and assets projected to be exposed to coastal risks as well as human pressures on coastal ecosystems will increase significantly in the coming decades due to population growth, economic development, and urbanization (high confidence).

The relative costs of coastal adaptation vary strongly among and within regions and countries for the 21st century. Some low-lying developing countries and small island states are expected to face very high impacts that, in some cases, could have associated damage and adaptation costs of several percentage points of GDP.

Healthy mangroves and sea grass beds will be needed for coastal protection in Utila, Honduras also in the future. Photo copyright (c) 2015 Erkki Siirila.

Healthy mangroves and sea grass beds will be needed for well-functioning coastal ecology and storm protection in Utila, Honduras, also in the future. Photo copyright (c) 2015 Erkki Siirila.

Marine systems

Due to projected climate change by the mid 21st century and beyond, global marine-species redistribution and marine-biodiversity reduction in sensitive regions will challenge the sustained provision of fisheries productivity and other ecosystem services (high confidence).

Spatial shifts of marine species due to projected warming will cause high-latitude invasions and high local-extinction rates in the tropics and semi-enclosed seas (medium confidence).

Species richness and fisheries catch potential are projected to increase, on average, at mid and high latitudes (high confidence) and decrease at tropical latitudes (medium confidence).

The progressive expansion of oxygen minimum zones and anoxic “dead zones” is projected to further constrain fish habitat.

Open-ocean net primary production is projected to redistribute and, by 2100, fall globally under all scenarios.

Climate change adds to the threats of over-fishing and other nonclimatic stressors, thus complicating marine management regimes (high confidence).

For medium- to high-emission scenarios, ocean acidification poses substantial risks to marine ecosystems, especially polar ecosystems and coral reefs, associated with impacts on the physiology, behavior, and population dynamics of individual species from phytoplankton to animals (medium to high confidence).

Ocean acidification poses substantial risks to the health of reef-building corals. Photo from Utila, Honduras. Copyright (c) 2015 Erkki Siirila.

Ocean acidification poses substantial risks to the health of reef-building corals. Photo from Utila, Honduras. Copyright (c) 2015 Erkki Siirila.

Highly calcified mollusks, echinoderms, and reef-building corals are more sensitive than crustaceans (high confidence) and fishes (low confidence), with potentially detrimental consequences for fisheries and livelihoods.

Ocean acidification acts together with other global changes (e.g., warming, decreasing oxygen levels) and with local changes (e.g., pollution, eutrophication) (high confidence). Simultaneous drivers, such as warming and ocean acidification, can lead to interactive, complex, and amplified impacts for species and ecosystems.

Source: IPCC, 2014: Summary for policymakers. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1-32.

Ocean state alarming – policy changes are needed

Text and photos (c) 2013 Erkki “Eric” Siirila, copyright & all rights reserved. 

Urgent measures are needed to stop ocean degradation related to climate change. The speed and negative effects are greater and more clearly felt that previously thought. These are the most important conclusions of recent work by an international marine scientist panel.

The results of the latest wide-ranging international review were made public by the World Conservation Union (IUCN) at the beginning of October 2013. Behind the work were the experts of IUCN and International Programme of the State of the Ocean (IPSO). The outcomes have also been published in the scientific journal Marine Pollution Bulletin.

Evening in the South Atlantic.

Evening in the South Atlantic.

An IUCN press release highlights the contents by telling us the following preoccupying facts: The ocean is absorbing much of the global warming. Unforeseen levels of carbon dioxide are bound by the ocean. The cumulative impact of this, together with other ocean stressors, is much more threatening than past estimates.

The other contributing stressors include decreasing oxygen levels in the sea and runoff of nitrogen from land. Also chemical pollution and serious overfishing are hampering the ocean’s capacity to act as a balancing factor in what is called “carbon preturbations”.

A comment by Professor Alex Rogers of Somerville College, Oxford (also Scientific Director of IPSO) is cited in the IUCN summary paper: “The health of the ocean is spiraling downwards far more rapidly than we had thought. We are seeing greater change, happening faster, and the effects are more imminent than previously anticipated. The situation should be of the gravest concern to everyone since everyone will be affected by changes in the ability of the ocean to support life on Earth.”

Professor Dan Laffoley, from IUCN, commented the new interdisciplinary findings by saying: “What these latest reports make absolutely clear is that deferring action will increase costs in the future and lead to even greater, perhaps irreversible, losses. The UN climate report confirmed that the ocean is bearing the brunt of human-induced changes to our planet. These findings give us more cause for alarm – but also a roadmap for action. We must use it.“

Dead fish on the beach of Bombinhas, Brazil.

Dead fish on the beach of Bombinhas, Brazil.

More in depth, the foreseen challenges and problems include the following:

Oxygen levels in the ocean are expected to decline between 1% and 7% by 2100.  Tropical  oceans and and the North Pacific have had a trend of decreasing oxygen levels during the past 50 years and this will continue because of global warming. In addition, lack of oxygen will be a serious problem in coastal seas commonly affected by eutrophication (sewage and agricultural runoff being the main reasons).

In case CO2 release by us planet Earth inhabitants continues at the current level, acidification of sea water will be a major factor affecting ocean life, marine food production and coastal protection. Acidification would be felt for example on coral reefs, where erosion in the near future could exceed reef formation (calcification). This in turn would degrade the reef habitat and result in the destruction of the natural breakwaters formed by corals – a serious consideration in coastal regions commonly hit by heavy storms.

As to the direct physical and geochemical consequences of global warming in the ocean by 2050, they include: reduced seasonal ice zones, increasing stratification (separation) of ocean layers leading to oxygen depletion, increased venting of methane from the bottom of the Arctic Sea, and more common low oxygen -events in the oceans.

Around the globe, fisheries management is still unable to stop overfishing. The decline of key species and damage to the ecosystems where the fish stock live continue. All this undermines the resilience of the oceans.

Unauthorised fishing in the national economic zone: Argentine coast guard proudly presents the foreign fishing vessels detained by its patrol vessel. Photo from Puerto Madryn, Argentina.

Unauthorised fishing in the national economic zone: Argentine coast guard proudly presents the foreign fishing vessels detained by its patrol vessel. Photo from Puerto Madryn, Argentina.

Urgent measures proposed by IPSO and IUCN include:

Reduction of global CO2 emissions to keep temperature rise in less than 2 degrees C.

Implementation of community- and ecosystem-based management and favouring small-scale fisheries. Harmful fisheries’ subsidies resulting in overcapacity would need to be eliminated. In addition, vulnerable ecosystems would need an increased level of protection. Finally, illegal, unreported and unregulated fishing would need to to be combated.

Development of a more relevant global infrastructure for high-seas ocean governance is necessary. Especially a new implementing agreement for the conservation and sustainable use of biodiversity in areas beyond national jurisdiction is needed (within the United Nations Law of the Sea – UNCLOS – framework).

Carbon sink and diversity oasis – Kelp forests are abundant in the coastal waters of all continents

Text and photos (c) 2013 Erkki “Eric” Siirila, copyright & all rights reserved. 

Orange garibaldis, the “official” fish of California, are the first thing I see while entering the undersea kelp jungle of Santa Catalina Island outside Los Angeles. In front of me 50-60-meter long stalks of Macrocystis pyrifera rise from the depth of 20 meters to the surface. They get their buoyancy from gas filled bladders called pneumatocysts. When a diver explores the forest formed by the biggest kelp species in the world, not only the size amazes. Also the growth speed, which in the favorable conditions of southern California may reach 45-50 cm in 24 hours, seems unbelievable.

Diving in a kelp forest is an unforgettable experience.

Diving in kelp forests provides unforgettable experiences.

Even though most kelp areas in California are protected, some others are being utilized for kelp harvesting. Harvesting takes place also in the kelp beds of Baja California, Mexico. Algin, the chemical extracted, is used for getting the right smoothness and thickness, when chemical, cosmetic, pharmaceutical and food processing industries make products for you.

A garibaldi in the waters of Santa Catalina.

A garibaldi in the waters of Santa Catalina.

Charles Darwin highlighted the biodiversity of Macrocystis habitats in the following words: “If in any country a forest was destroyed, I do not believe nearly so many species of animals would perish as would from the destruction of kelp.” In spite of being a statement before the ultra high diversity of the tropical rains forests was known to scientists, the comment still indicates something very basic about the importance of the kelp communities.

Gas-filled pneumatocysts give the kelp stalks buoyancy.

Gas-filled pneumatocysts give the kelp stalks buoyancy.

After the dive, together with diver colleagues we summarize our underwater experiences: the peak moments included encounters with a spiny lobster, horn shark and hawksbill turtle. From the shore I see an American blue heron searching for food on top of the floating kelp. Around the Macrocystis communities I also observe harbor seals and California sea lions. In the undersea jungles of Southern California at least 750 species of fish and invertebrates are known to live. A single kelp stalk may be the home to half a million critters.

Holdfasts anchor the kelp to the sea bottom.

Holdfasts anchor the kelp to the sea bottom.

The same kind of examples from the ocean´s forests are being told around the world. So it is no wonder that the environmental organization Oceana has started to defend the kelp beds, which are found close to shore in regions where the waters are cool – each continent, except the Antarctic, has thousands of kilometers of coast where kelp is an important part of undersea nature (see Kelp forest distribution map). In spite of this, internationally there is little environmental legislation protecting these undersea habitats. Of course all the underwater forests are not as mighty as those built by Macrocystis. In Europe, the kelp communities are formed by Laminaria species, which are common in Norway, to give one example. There they reach a height of two to five meters.

My dive continues with photography of sea urchins, which can be found under rocks at daytime. The urchins are the main enemy of Macrocystis. They eat and destroy Macrocystis´ holdfasts, the “roots” of the giant kelp. In the Santa Catalina waters there are only few urchins. In consequence, the kelp forest looks healthy. When I see a 60-centimeter California sheephead in the viewfinder, I feel grateful to it. The urchins are part of its diet. The fish, which regularly approaches divers and gives the impression of being intelligent, is well known to the Catalina visitors. This exceptionally big individual is easily recognizable and has gotten the name Oscar.

California sheephead keep the sea urchin populations under control.

California sheephead is a fish species which controls the sea urchin populations.

Like Oscar also Californian divers have supported the survival of kelp by removing sea urchins from key bottom areas. The urchin numbers had grown much higher than normal. This lack of balance had mostly resulted from the hunting and overfishing of their natural enemies. In addition to urchin control, in California techniques have been developed to help young and drifting kelp attach to the sea floor. The support actions have resulted in the return of kelp to areas where Macrocystis had disappeared.  For Santa Catalina, healthy kelp forests have become a major attraction which draws thousands of tourists to the island every year.

In Monterey I photograph the graceful sea otters. Here the good news is that the otter population of central and northern California, which was practically destroyed by fur hunters, has significantly grown. In 2013 an estimated 3,000 sea otters live in the region. The animal prays on sea urchins and, when abundant, keeps their numbers at an environmentally sound level.

When sea urchin populations grow in an uncontrolled manner, they can destroy entire kelp forests.

When sea urchin populations grow in an uncontrolled manner, they can destroy Macrocystis forests.

The value of the sea otters and kelp forests off the Pacific coast of North America got a new recognition some time ago. In the October 2012 issue of Frontiers in Ecology and the Environment, Christopher C Wilmers, James A Estes, Matthew Edwards, Kristin L Laidre, and Brenda Konar presented a study which covers the Macrocystis-dominated kelp forests from Vancouver Island to the western edge of Alaska´s Aleutian Islands.

Sea otters feed on sea urchins and can be extremely useful to kelp forest wellbeing.

Sea otters feed on sea urchins and support the survival of kelp communities.

The main conclusions include that in areas where the otters are abundant and at their natural levels, they suppress the sea urchin populations significantly, i.e. so much that the kelp forests flourish. Every year the additional kelp is estimated to capture as much carbon dioxide from the atmosphere as the CO2 production of three to six million passenger cars in 12 months. In ideal conditions, the kelp forests’ capacity to store carbon equals that of a tropical rain forest of the same size.  Thus the kelp forests (especially those dominated by Macrocystis) are an important carbon sink slowing down climate change and global warming.

Progress in Tela reef conservation in Honduras

Text and photos (c) 2013 Erkki “Eric” Siirila, copyright & all rights reserved. 

Some years ago the city of Tela in Honduras was only known for its beaches. No one was aware that underwater additional national heritage could be found. The coral reefs of the Tela Bay are this other treasure.

The Tela Bay in Honduras has coral reefs, the conservation of which needs attention. Photographer and copyright (c) 2013 Erkki Siirila.

The Tela Bay in Honduras has coral reefs, the conservation of which needs attention. Photographer and copyright (c) 2013 Erkki Siirila.

Francois Ligeard, The Chamber of Tourism of Tela, says: “The good news is that we can offer a new site for both the national and international tourist. We have to highlight the fact that this place is very beautiful. It has high cover of live coral. We notice that always when we dive on this reef. One easily gets emotional because every time we go the local reef we find something new and more beautiful.”

Dennis Sierra, The Prolansate Conservation Foundation, Tela, sees the “newly discovered” coral reefs in the following way: “The best news is that in Tela we have many people both in the civil society, local government and the business sector who are very interested in the conservation of the coral banks of the Tela Bay. The preservation needs have an acceptance at the community level. Also at the level of the central government there is a lot of interest in declaring a marine park in the Bay of Tela.”

Only fishing was done on the local Capiro Reef in the past. Nowadays, divers come here to see the angelfish and the many species of coral. For example, black coral is found here.

The coral bank of Capiro is the best known reef area in the Tela waters. Photo and copyright (c) 2013 Erkki Siirila.

The coral bank of Capiro is the best known reef area in the Tela waters. Photo and copyright (c) 2013 Erkki Siirila.

Dennis Sierra: “Logically we look toward the future generations. We need to implement conservation actions in the Bay area, if we want to leave this ecosystem as a heritage to our children. Tela has been favored by God. We have to remember that the natural richness we have in Tela contributes in a positive way to tourism opportunities here. Tela has its future in the resources of that Bay.”

Francois Ligeard: “The biggest challenge we face is to take care of the reef both for our generation and the future generations. We need to get the fishermen and other local people involved to be able to preserve this reef. We have been working already by installing permanent mooring buoys. In this way, we need not anchor the boats and we can stop the damage that has been caused to the reef by anchors in the past.”

The mangroves of the Bay may not be forgotten as reef conservation is promoted. The mangroves produce nutrition for marine life. In addition, among the roots, many species of coral reef fish live during their juvenile stage. The mangroves also protect the coast from the waves of the sea.

The seagrass beds in the Tela waters have functions similar to those of the mangroves. In addition, many reef fish migrate to the seagrass areas in order to eat.

When forests are preserved, there is only little erosion on land and less mud enters the sea via the rivers. This is crucial in reef conservation as the corals need clean and clear water. Related to the above, it is also necessary to develop the treatment of sewage and waste waters.

In the Tela Bay there are very healthy coral colonies. It is important to take care of the reefs, because climate change threatens them, through the elevated sea-water temperatures and through the acidification of the sea.

Coral reefs will be more resistant to global environmental changes, when at the local level there is no overfishing and when the other pressures are kept at the minimum level. In this way, the coral reefs of Tela will produce economic and environmental benefits to us also in the future.

The following Youtube video was shot and produced by the Coastal Challenges’ Editor. It tells the above story of the Tela coral reefs in Spanish. The original is in high definition; this lower-resolution Youtube version can be best seen be adjusting the image resolution under the Youtube window to 480 p.