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.

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.

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.

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.

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:

http://www.worldwildlife.org/publications/living-blue-planet-report-2015 http://ocean.panda.org/media/Living_Blue_Planet_Report_2015_Final_LR.pdf

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.

• 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.

Oceans and coasts, a key component on the new UN agenda for sustainable development

Transforming our world, the 2030 agenda for sustainable development (advance unedited version) was published by the UN in August 2015. In chapter 14, the document highlights important marine and coastal management topics. The following is a direct citation from the new agenda. This is what is needed for sustainable management of oceans, seas, coasts and marine resources in the coming years:

Goal 14. Conserve and sustainably use the oceans, seas and marine resources for sustainable development

14.1 By 2025, prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution

14.2 By 2020, sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts, including by strengthening their resilience, and take action for their restoration in order to achieve healthy and productive oceans

14.3 Minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels

14.4 By 2020, effectively regulate harvesting and end overfishing, illegal, unreported and unregulated fishing and destructive fishing practices and implement science-based management plans, in order to restore fish stocks in the shortest time feasible, at least to levels that can produce maximum sustainable yield as determined by their biological characteristics

Fish trap on a Saint Lucian coral reef in the Caribbean. Trap fishing in reef areas needs to be regulated. Photographer and copyright (c) 2015 Erkki Siirila.

14.5 By 2020, conserve at least 10 per cent of coastal and marine areas, consistent with national and international law and based on the best available scientific information

14.6 By 2020, prohibit certain forms of fisheries subsidies which contribute to overcapacity and overfishing, eliminate subsidies that contribute to illegal, unreported and unregulated fishing and refrain from introducing new such subsidies, recognizing that appropriate and effective special and differential treatment for developing and least developed countries should be an integral part of the World Trade Organization fisheries subsidies negotiation (taking into account ongoing World Trade Organization negotiations, the Doha Development Agenda and the Hong Kong ministerial mandate)

14.7 By 2030, increase the economic benefits to Small Island developing States and least developed countries from the sustainable use of marine resources, including through sustainable management of fisheries, aquaculture and tourism

14.a Increase scientific knowledge, develop research capacity and transfer marine technology, taking into account the Intergovernmental Oceanographic Commission Criteria and Guidelines on the Transfer of Marine Technology, in order to improve ocean health and to enhance the contribution of marine biodiversity to the development of developing countries, in particular small island developing States and least developed countries

14.b Provide access for small-scale artisanal fishers to marine resources and markets

14.c Enhance the conservation and sustainable use of oceans and their resources by implementing international law as reflected in UNCLOS, which provides the legal framework for the conservation and sustainable use of oceans and their resources, as recalled in paragraph 158 of The Future We Want

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 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.

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.

Microplastic pollution – a serious threat to marine ecosystems

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

Pioneering research has shown that plastic waste entering the ocean may have more serious negative effects on marine life than what was previously thought. Two studies published in Current Biology focus on the ecosystem effects of microplastic fragments less than 1 mm in diameter. The very small pieces of plastic have been polluting the ocean for about half a century.

Previous research has concentrated on the effects of bigger plastic objects in the marine ecosystem. This time the focus is on the fragments, which are produced for example as a result of gradual breakdown of plastic bottles in nature.

The tiny plastic particles are so small that wastewater treatment plants cannot stop them from entering the sea. A serious challenge for waste management is that this pollution does not originate only in what we normally consider plastic. The sources include synthetic textiles e.g. polyester – many of our clothes release a high number of microscopic pieces of plastic fibre when they are washed. Microbeads from cosmetic facial scrubs are one more source of harmful plastic particles. On the shores and in the sea, the microscopic plastic waste sinks into the sediments in high concentrations.

An additional problem with microplastics is that, in addition to the direct effects, they transfer harmful chemicals to marine organisms eating them. This was shown to take place in the case of lugworms by Mark Browne and his colleagues (link to Abstract). Lugworms (Wikipedia Lugworm) are an example of a common North Atlantic species using the sediments as food source. Starfish and sea cucumbers have similar feeding strategies. Mark Browne’s work was completed at Plymouth University, UK.

Plastic waste entering the Atlantic via Rio de la Plata (River Plate), Buenos Aires, Argentina.

The harmful substances within the microplastics include antimicrobials, hydrocarbons and flame retardants, which are often persistent and may reduce health and biodiversity. Furthermore, minute plastic particles concentrate substances from the surrounding water on their surface: to name two examples, detergents and pesticides can be detected. The chemicals may be carried over to the next predators in the food chain – lugworms are eaten by flounders and wading birds. The harmful substances could also accumulate in the top predators, perhaps even in us humans. If lugworms are seriously affected, as they are, the whole food chain could be subject to significant adverse effects.

In the study by Stephanie Wright, University of Exeter, UK, and her colleagues, it was found that those lugworms which (in laboratory tanks) were subject to varying levels of plastic contamination, gained less weight than the worms in a clean environment. Consequently, the worms suffering from the consequences of plastic pollution had less energy for growth and reproduction. The worms were also likely to be less efficient in their important ecosystem service, i.e. in eating and keeping the sediments healthy and oxygenated for other animals. The article by Wright et al. is here: http://download.cell.com/current-biology/pdf/PIIS0960982213013432.pdf?intermediate=true .

When interviewed by the BBC, Dr Browne summarised his earlier findings relating to 18 sediment samples from the beaches in several countries: “We found that there was no sample from around the world that did not contain pieces of microplastic.”

Based on these two ground-breaking articles in Current Biology, there seems to be an urgent need to develop the use practices and waste management techniques of plastic products in our societies. This is an important coastal and marine conservation issue.

In addition to the material published in Current Biology, summaries published by the British BBC and The Guardian, were helpful in the preparation of this Coastal Challenges’ article.

 

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.

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.

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.

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).