Geology for Global Development

Sustainable Development Goals

Weighing up the pros and cons of artificial coral reefs

Weighing up the pros and cons of artificial coral reefs

The world’s oceans cover 71% of the Earth’s surface and contain 97% of Earth’s water. They play a key role in the climate cycle and, though perhaps not always visibly, are suffering significantly under our changing climate. An place where we can see the alarming effects of rising temperatures and increasingly acidic waters is coral reefs, which experienced the longest, most widespread, and possibly the most damaging coral bleaching event on record between 2014 and 2017. In today’s post, Heather Britton compares natural vs. artificial coral reefs in the context of protecting life below the water (UN sustainability goal 14).

Reefs around the world are dying – approximately half of the world’s coral reefs have disappeared over the past 30 years, and many are showing signs of following in their stead – be it due to increased water temperature, sea level change or an influx of sediment in previously nutrient-poor conditions. Many of the factors contributing to the bleaching and eventual death of these ecosystems stem from the impact of people, such as global warming and the development of resorts in the vicinity of fragile reef environments.

The disappearance of coral reefs would lead to a catastrophic loss of biodiversity – coral reefs are thought to be the most biodiverse ecosystems on the planet, displaying a greater variety of life than even rainforests, and it is clear that we need to act now if these environments are to be saved – for many reefs it is already too late.

One popular response to the loss of natural coral reefs has been to construct artificial reefs, replacing those that have died and providing a habitat for organisms that may otherwise become extinct. These structures take a plethora of forms, from sunken ships to cinder block stacks, but as long as they are made of a hard substrate and are able to offer protection and a place for sheltering organisms to spawn there is potential for a reef to develop in as little as two-three years.

In many ways, this is an elegant solution. Not only do artificial reefs help to combat the loss of biodiversity associated with the decline of their natural counterparts, but they attract divers and other tourists to the sites where they are placed, bringing in tourism and strengthening the economy in the area. This benefit is particularly valuable to lower income countries, some of which boast extensive coral reef ecosystems. In addition, reefs are known to concentrate fish populations and therefore are popular with the fishing industry worldwide – the first recorded artificial reefs were developed by fishermen in Japan in the 18th century, who sunk makeshift shelters to increase their haul. Reefs form from man-made substrates relatively easily, and they are certainly preferable to a lack of reefs altogether – but can artificial reefs really ever match their natural cousins?

Diver installing ocean-chemistry monitoring equipment at Florida Keys. Credit: Ilsa B. Kuffner (U.S. Geological Survey). Distributed via U.S. Geological Survey. 

Artificial reefs are created extensively off the coast of Florida, as much for the economic benefit that the tourism brings (both through fishing and diving) as increasing ocean biodiversity. The region is encountering problems, however, one of which is local people choosing to develop their own personal reefs using suboptimal materials. For example, tyres, when strapped together, attract aquatic organisms as they provide a place to spawn and the shelter of a natural reef, but the toxicity of the rubber can negatively impact the environment in ways that a ship or concrete blocks will not. Ships that are sunk professionally for the purpose of artificial reef formation are extensively prepared before they are placed underwater, whereas amateurs rarely take the time to prepare their seeding structures properly. This has led some countries, such as Australia, to develop laws against the formation of artificial reefs without a permit.

Artificial reefs are also celebrated because they attract divers away from the surviving natural reefs, meaning that each individual reef is less damaged by people. It is also possible, however, that the number of tourists in total might increase in response to the increased number of dive-sites, having the opposite effect and causing dive sites in the region to become more popular.

Arguably, the most important question to be asked when discussing natural vs artificial reef structures is: do artificial reefs have biodiversity equivalent to that of natural reefs? The answer is unclear, but it certainly seems that the biodiversity of each kind of reef is different. Artificial reefs, at first glance, seem to attract more fish to them than natural reefs. This suggests that that artificial reefs may be encouraging fish to reproduce more than the naturally occurring reefs scattered throughout the oceans. However, many of the marine animals attracted to feed and shelter around artificial reefs do not breed there, and simply visit from other regions of the ocean. Artificial reefs therefore may only be acting to concentrate the fish in a single area, making them more susceptible to fishing and generally increasing the effect of fishing pressure on marine populations. This is commonly referred to as the ‘aggregation vs production’ debate. If the fish are more numerous at artificial reefs because they are breeding there, then the reef is likely acting to increase the population of that particular fish species and artificial reefs are helping to sustain the biodiversity of the oceans. If they are simply concentrating fish that typically spend their time swimming between reefs, however, fish numbers are likely to be negatively, not positively affected.

Dead corals turned to rubble, off the coast of the US Virgin Islands. Credit: Curt Storlazzi (U.S. Geological Survey). Distributed via U.S. Geological Survey.

A study on the Caribbean island of Bonaire provides some insight into the differences in diversity between natural and artificial reefs. Equal diversity was found at partnered artificial and natural reefs, but the composition of this diversity was starkly different. Whilst the sergeant major and bluehead wrasse fish were most commonly seen on the artificial reef, the natural was more commonly frequented by bicoloured damselfish and brown chromis. Similar trends were visible within the benthic community of organisms, suggesting that although artificial reefs may preserve the diversity that we see within the oceans today, some organisms appear to populate natural reefs to a far greater extent than their artificial counterparts, and these species may still be lost.

For this reason it is of the utmost importance that every effort is made to protect the natural coral reefs of today, thereby working to achieve UN sustainability goal 14 (Life below the Water). Artificial reefs are helping to preserve the biodiversity of the oceans and save countless organisms from extinction, but it is important to remember that what causes the corals of natural reefs to die will also impact the corals which begin to grow on artificial reefs. In order to prevent the loss of these ecosystems we need get to the root of the problem and combat the things that are harming coral reefs – global warming, human physical destruction of reef environments and the pollution of our oceans.

The Sustainability Argument for Open Access Publishing

The Sustainability Argument for Open Access Publishing

Those who follow the work of GfGD, either via posts on this blog or more direct engagement, will know that there are a multitude of connections between geoscience and the Sustainable Development Goals. The SDGs are almost impossible to disentangle from resource use and environmental pressures, subjects which are themselves cornerstones of modern geoscience.

While this may be the case, a key question that I’ve heard from some colleagues goes something like this: “My research project might have implications for sustainability in the long term, but my primary research isn’t focused on the SDGs. How can I make a difference to attaining the goals?”

It’s true that many earth scientists aren’t specifically working on addressing the SDGs; the actual action is often left to policy makers and NGOs. So what’s the best way to help, if your work might have some input? One answer comes to mind quickly – get your work out to these stakeholders through science communication. However, this isn’t to everyone’s taste, and not every scientist is comfortable in the social-media communication sphere. It’s often tricky to reach all the potential stakeholders all at once, so is there an alternative solution that doesn’t require devoting too much time to public-facing communication?

Yes – you can publish open access.

Open access journals – where there aren’t subscription fees to view an article, and costs are covered by external agencies or through article processing charges – have disrupted science publishing significantly over the last 15 years. The question over open access research journals is a complex and fraught one; many scientists feel strongly one way or the other, and large scale legal battles are playing out between governments and traditional publishing houses in relation to demands for open access science.

I’m not taking a position as to whether open access is a good model for science or researchers, but instead I’d suggest that it can help attain SDGs – particularly if it’s geoscience research that’s published for all to see.

As an early career researcher, I tended to think that open access might not make such a difference to my own work; the public wouldn’t be interested in my extremely niche topic of research. I didn’t consider that there might be different groups of readers for whom geoscience research might make more impact than for my friends and family. Government researchers and NGO analysts working in the developing world vitally need access to data and science, but their budgets may not stretch to pay for access to subscription journals. These are the important stakeholders for the attainment of SDGs, and these are the end-users of open access research we should consider more.

Let’s use mining as an example. Given the same absolute amount of mineral or fossil resources, historical evidence suggests that a country in the global south would likely only find 1/5 of the amount that a rich country would. Exploration and utilisation of a nation’s mineral wealth requires a clear understanding of resource science, which may be lacking in developing states due to lack of access to published research. This is such a significant issue that the World Bank in 2014 set out to spend $1 billion to produce geological maps of Africa’s natural resources, for governments there to better use their resources.

For the global south, a lack of data surrounding their own resources – particularly fossil fuels – puts them at a huge disadvantage when negotiating contracts with multinational petrochemical or mining corporations. Global firms like Exxon or Shell have huge, dedicated R&D arms, with larger research budgets than many developing countries can muster. The effect is that the two parties have ‘asymmetric information’; according to economics, this situation almost always leads to less-than-optimal outcomes, and it’s normally the party with less information that loses out. In real terms, this could mean mining firms negotiating contracts that might underplay the risk and pollution from extraction for local communities.

Using resources sustainably and carefully is at the heart of efforts to attain the sustainability goals. Water quality suffers when pollution is extensive; poverty and inequality are exacerbated by inefficient and corrupt management of income from mining or drilling; the effective use of taxes from mining and fossil fuel extraction can help build sustainable infrastructure for a greener future.

Open access geological data allows governments in the global south to make more informed decisions about their own national resources, and fosters a framework of openness that encourages greater accountability. It prevents vulture companies exploiting those nations, too, which is a key aspect in the fight for global equality.

Another classic geological field of study is natural hazards, and here too open data can be crucially important. According to a study published by the Open Data Institute,

“Open data can help to inform evidence-based policy-making and the design of government services. It offers policy-makers a source of information to identify wasteful spending, better target resources and design more responsive services. Although open data can be useful to most services, to date it has been especially relevant in the areas of healthcare, education, disaster risk management and transportation.”

The global south are likely to face more severe threats to life and economic growth as a result of climate change than developed states (e.g. this report by DARA), and this potential risk is exacerbated when governments lack sufficient data to make informed policy decisions. Climate change has the potential to adversely impact almost all of the sustainability goals, from resolving inequality, to food security, to life on land and in the ocean. The global scale of climate change makes it in everyone’s interest to encourage smart policy making in every country – and thus a great incentive for scientists and policy-makers to support open-access research.

Perhaps there are other more important incentives for earth scientists to publish in other journals; but in future, perhaps we should consider the ramification of our publishing choices for sustainability. Maybe the ‘social impact’ factor of research is more relevant than the publication impact factor.

Robert Emberson is a science writer, currently based in Vancouver, Canada. He can be contacted via Twitter (@RobertEmberson) or via his website (www.robertemberson.com).

**This article expresses the personal opinion of the author. These opinions may not reflect official policy positions of Geology for Global Development.**

Saltwater intrusion: causes, impacts and mitigation

In many countries, access to clean and safe to drink water is often taken for granted: the simple act of turning a tap gives us access to a precious resource. In today’s post,Bárbara Zambelli Azevedo, discusses how over population of coastal areas and a changing climate is putting ready access to freshwater supplies under threat. 

Water is always moving downwards, finding its way until it gets to the sea. The same happens with groundwater. In coastal areas, where fresh groundwater from inland meets saline groundwater an interesting dynamic occurs. As salt water is slightly denser than freshwater, it intrudes into aquifers, forming a saline wedge below the freshwater. This boundary is not fixed, it shows seasonal variations and daily tidal fluctuations. It means that this interface of mixed salinity can shift inland during dry periods, when the freshwater supply decreases, or seaward during wetter months, when the contrary happens.

Freshwater and saltwater interaction. Credit: The National Environmental Education and Training Foundation (NEEF).

Once saline groundwater is found where fresh groundwater was previously, a process known as saltwater intrusion or saline intrusion happens. Even though it is a natural process, it can be influenced by human activities. Moreover, it can become an issue if saltwater gets far enough inland that it reaches freshwater resources, such as wells.

According to the UN report, about 40% of world’s population live within 100km from the coastline or in deltaic areas. A common source of drinking water for those coastal communities is pumped groundwater. If the demand for water is higher than its supply, as can often occur in densely populated coastal areas, the water pumped will have an increased salt content. As a result of overpumping, the groundwater source gets contaminated with too much saltwater, being improper for human consumption.

With climate change, according to the IPCC Assesment Reports, we can expect  sea-level to rise, more frequent extreme weather events, coastal erosion, changing precipitation patterns and warmer temperatures. All of these factors combined with the a increased demand for freshwater, as a result of global population growth, could boost the risk of saltwater intrusion.

Shanghai – an example of densely-populated coastal city. By Urashimataro (Own work) [CC BY-SA 3.0 ],via Wikimedia Commons.

Although small quantities of salt are important for regulating the fluid balance of the human body, WHO advises that consuming higher quantities of salt than recommended can be associated with adverse health effects, such as hypertension and stroke. In this manner, reducing salt consumption can have a positive effect in public health, helping to achieve SDG 3.

With the aim of preserving fresh groundwater resources for coastal communities at present and in the future, dealing with the threat of saline intrusion is becoming more and more important.

Therefore, to be able to mitigate the problem, first of all, it needs to be better understood. This can be done by characterising, modelling and monitoring aquifers, assessing the impact and then drawing solutions. Currently there are many mitigation strategies being designed worldwide. In Canada, for example, the adaptation options rely on monitoring and assessment, regulation and engineering. In the UK, on the other hand, the simpler solution adopted is reducing or rearranging the patterns of groundwater abstraction according to the season. In Lebanon, a fresh-keeper well was developed as an efficient, feasible, profitable and economically attractive way to provide localised solution for salination.

Every case should be analysed according to its own characteristics and key management strategies adopted to ensure that everyone has access to clean and safe water until 2030 – SDG6.

How do you monitor an internationally disruptive volcanic eruption? How can you communicate SDGs in an Earth Science class? Jesse Zondervan’s Nov 13 – Dec 13 2017 #GfGDpicks #SciComm

Each month, Jesse Zondervan picks his favourite posts from geoscience and development blogs/news, relevant to the work and interests of  Geology for Global Development . Here’s a round-up of Jesse’s selections for the past four weeks:

Bali’s Mount Angung started erupting ash this month, and a post on the Pacific Disaster Center’s website gives you an insight into the workings of Indonesia’s early warning and decision support system. How do you monitor an internationally disruptive volcanic eruption?

In Japan, eruptions in 2016 were preceded by large earthquakes (MW 7.0). A team of researchers used Japan’s high resolution seismic network to investigate the underground effects of earthquakes and volcanoes. How does an earthquake affect a volcano’s activity?

Next to plenty of disaster risk stories – including the simple question: why can’t we predict earthquakes? -, this month brings you a computer simulation tool to predict flood hazards on coral-reef-lined coasts and some thoughts on how to communicate SDGs in an earth science classroom.

Have a look!

Education/communication

The UN Sustainable Development Goals – what they are, why they exist by Laura Guertin at AGU’s GeoEd Trek blog

GeoTalk: How an EGU Public Engagement Grant contributed to video lessons on earthquake education by Laura Roberts-Artla at the EGU’s GeoTalk blog

Credit: Michael W. Ishak, used under CC BY-SA 4.0 license

Disaster Risk

Disaster Geology: 2017’s Most Deadly Earthquake by Dana Hunter at Scientific American

Can the rubble of history help shape today’s resilient cities? By David Sislen at Sustainable Cities

The underground effects of earthquakes and volcanoes at phys.org

Why Can’t We Predict Earthquakes? By David Bressan at Forbes

Detecting landslide precursors from space by Dave Petley at the AGU Landslide Blog

Ocean Sediments Off Pacific Coast May Feed Tsunami Danger by Kevin Krajick at State of the Planet

Life-saving technology provides alert as Bali’s Mount Agung spews ash, raises alarm at Pacific Disaster Center

Climate Change Adaptation

Scientists counter threat of flooding on coral reef coasts by Olivia Trani at AGU’s GeoSpace blog

Check back next month for more picks!

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