Geology for Global Development

Oceans

The importance of wetlands

The importance of wetlands

World Wetlands day is celebrated on 2nd February, marking the adoption of the Convention on Wetlands, also known as Ramsar Convention, in the Iranian city of Ramsar on 2nd February 1971. It “provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.

Today 170 countries have adopted it and 2,341 Ramsar sites covering over 2,5 million km² are designated as Wetlands of International Importance. But what are wetlands and why should we care about them? I’ll address these questions and other important points in this article.

First, what are wetlands?

Basically, a wetland is an area of land that is covered with water, whether natural or artificial, permanent or temporary. This water can be salt, fresh or somewhere in between, and have a maximum depth of six metres. Mangroves, marshes, ponds, peatlands, swamps, deltas, estuaries, low-lying areas that frequently flood are all wetlands and they can be found on every continent. Some of the largest ones are the Sundarbans mangrove forest in the Ganges-Brahmaputra delta in Bangladesh, the Amazon River basin (figure below), and the Pantanal, both in Brazil.

Wetlands cover about 3% of world’s surface. A web-based map shows the global distribution of wetlands and peat areas. It was launched in 2016 by researchers from Sustainable Wetlands Adaptation and Mitigation Program – SWAMP and is based on satellite images acquired by the  Moderate Resolution Imaging Spectroradiometer (MODIS) instrument.

Why should we care about wetlands?

Wetlands are rich but also fragile environments. They can provide water, fish/biodiveristy, recreational areas and help to regulate the climate.

  • Biodiversity: Wetlands function as wildlife refuge, supporting high concentration of mammals, birds, fish and invertebrates, being nurseries for many of these species.
  • Resources: Further, they can be a huge resource for humans, supporting rice paddies (Figure 2), a staple food. They also help purify water by trapping pollutants and heavy metals in the soil and neutralizing harmful bacteria by breaking down suspend solids in the water.
  • Geohazards: Wetlands provide flood control and storm protection in coastal areas acting like a sponge during storm events such as hurricanes, reducing their power of destruction.
  • Climate change: Here is another important point that I would like to highlight about wetlands. They play an important role in climate change mitigation and adaptation, since they store huge amounts of carbon. If you are curious about this topic, see this post where Heather [a regular contributor to the GfGD Blog] discusses how carbon is stored in peat soils in the tropics and the main threats to these areas.

Wetlands in Amazon river basin during the dry season (Oct 2017), close to Santarém, Brazil – Photo: Bárbara Zambelli

Threatened environment

Despite their social and ecological importance, wetlands are continuously being degraded and even destroyed worldwide. According to this research the world has lost 64-71% of their wetlands since 1900 AD. Here is a list of the main threats towards wetlands:

  • Pollution: Generally located in low-lying areas, they receive fertilizers and pesticides from agricultural runoff, industrial effluents and households waste or sewage. These pollutants have detrimental effects on water quality and threaten the fauna and flora of wetlands. As I mentioned before, wetlands work as water filters, therefore there is a growing concern about how pollution will impact drinking water supplies and wetland biological diversity.
  • Agriculture and urbanization: One of the biggest threats to this environment is its drainage to make room for agriculture and human settlements. Such activities are an increasing threat and they destroy the ecosystem and all the benefits wetlands can provide.
  • Dams: The construction of a dam alters the natural flow of water through a landscape. This alteration may lead to an increase or decrease of water flow through a wetland, being potentially harmful for wetland ecosystems. Thus, it is essential to choose the location of a dam wisely, to reduce the impact on existing ecosystems.
  • Climate change: Climate change is shifting the world’s temperature and precipitation patterns. Wetlands are getting lost due both too much and too little water. Shallow coastal wetlands such as mangroves are being swamped because of sea level rise. In areas affected by droughts, estuaries, floodplains and marshes are drying up. Wetlands and climate change are the theme of World Wetlands Day in 2019.

Opportunities – taking action

Wetlands are a critical environment and their effective management can give a substantial contribution to biodiversity conservation and restoration, maintaining its bioecological characteristics and allowing the using of resources economically.

According to SWAMP, “carbon-rich mangroves and peatlands are high priorities in climate change adaptation and mitigation strategies throughout the world.”

With their partners, SWAMP have developed a collaborative agenda expected to raise the awareness about sustainable management of wetlands in changing world and livelihoods of local communities. The Ramsar Convention, an international agreement, is still important today because it supports environmental policy development and it encourages countries to commit to it. It is also valuable as an international forum for gathering and sharing knowledge about sustainable wetlands management. Also international NGOs such as Worldwide Fund for Nature (WWF) and Wetlands International play an important role.

Finally, regarding the Sustainable Development Goals (SDGs), recently Ramsar published a briefing note of how wetlands can contribute to their achievement. Access it hereto find out more details.

Jesse Zondervan’s January 2019 #GfGDpicks: which climate adaptation methods are on the rise in 2019?

Jesse Zondervan’s January 2019 #GfGDpicks: which climate adaptation methods are on the rise in 2019?

Each month, Jesse Zondervan picks his favourite posts from geoscience and development blogs/news which cover the geology for global development interest. This past month’s picks include:  Why it’s so hard to predict tsunamis, which climate adaptation methods are on the rise in 2019 & opportunities for scientists to solve local challenges with Thriving Earth Exchange.  

Plastic waste in the oceans and on beaches visibly smashes itself back in our faces to trouble our consciences after attempts to dump and hide the consequences of human waste-production. The size of our triggered guilt aside, how does our plastic problem quantitively compare in scale to the problem of carbon dioxide emission? You may be surprised, or not.

More significantly, climate adaptation, rather than prediction or prevention, takes the foreground at the start of 2019. In a long-read worth having a cup of tea over, National Geographic reports ways of adaptation gaining steam, such as the American Geophysical Union’s Thriving Earth Exchange, a sort of tinder for scientists and communities facing challenges related to natural resources, climate change and natural hazards issue (see whether you can help!).

“The American Geophysical Union’s Thriving Earth Exchange, a sort of tinder for scientists and communities facing challenges related to natural resources, climate change and natural hazards issues”

In addition, consider the following about adaptation: if you want to built a sustainable water-energy-food nexus, how do you manage or cope with migration? After all, even though development efforts might be thwarted, migration is a very efficient coping mechanism. Tellingly, both America and Bangladesh have started relocating flooded communities.

In disaster risk, we are looking back at 2018:

When a tsunami triggered by a landslide caused by the Anak Krakatau eruption in Indonesia bypassed the tsunami-warning system put in place to warn for earthquake-induced tsunamis, the world was once more reminded of our inability to predict all hazards, and its consequences.

However, studies like the one which uncovered a historic South China Sea tsunami from the geological record help to dust off our hazy memories of such events. Timely, since large infrastructural projects like the Belt and Road initiative are in full swing planning harbours and nuclear plant locations.

While insurance company Munich Re captured the world’s natural disasters of 2018, the fourth-costliest year since 1980, in numbers, the Bank of England plans to test climate resilience of UK banks.

As usual, there is a lot to check out, so go ahead!

Climate Adaptation

Once derided, ways of adapting to climate change are gaining steam by Andrew Revkin at National Geographic

Water – Energy – Food – Migration Nexus

Water-Migration nexus and the human displacement discourse by Nidhi Nagabhatla at Future Earth blog

Hike in record-dry months for Africa’s Sahel worries scientists by Laurie Goering at BRACED

How technology is helping farmers predict and prepare for El Niño by Michael Hailu at Thomson Reuters Foundation

Sea-level migration

In first, Native American tribe displaced by sea gets land to relocate by Sebastien Malo at Thomson Reuters Foundation

Bangladesh lends land to islanders as water devours homes by Rafiqul Islam at Thomson Reuters Foundation

Bracing for climate change – a matter of survival for the Maldives by Hartwig Schafer at End Poverty in South Asia

Climate Change

The Ocean Garbage Patch Is Tiny Compared to Our Carbon Footprint by Sarah Burns at State of the Planet

Disaster Risk

Why the ‘Child of Krakatau’ volcano is still dangerous – a volcanologist explains by Thomas Giachetti at The Conversation

The Anak Krakatau Tsunami, from the Beginning until Now by Dana Hunter at Scientific American

Scientists say a tsunami hit China 1,000 years ago – and there’s still a risk of a giant wave hitting today by Martin Choi at the South China Morning Post

The natural disasters of 2018 in figures by Petra low at Munich Re

Bank of England plants to test climate resilience of UK banks at Acclimatise

External Opportunities

CfP – 2019 Mexico Conference on Earth System Governance

Multiple positions in the field of climate adaptation governance (post-doc and doctoral researchers)

Seeking Book Proposals on Water, Green Infrastructure, Climate Change Adaptation, and Public Health

 

Check back next month for more picks!

Follow Jesse Zondervan @JesseZondervan. Follow us @Geo_Dev & Facebook.

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.

Robert Emberson: Microplastic – Too Important to Ignore

Anyone lucky enough to catch any of the BBC’s recent new series Blue Planet II will have noticed that each episode devotes a portion of the time to the impact humans have on the oceans. A breathtaking series of shots from a recent episode detailed the heart-wrenching demise of a baby whale, possibly poisoned by its mother’s milk due to toxins from plastic pollution. Vast quantities of plastic now cover the surface of the ocean, a point the series makes well. We’re now increasingly aware of the risks this plastic introduces, but there’s one part of the problem that scientists have only recently begun to appreciate – so called ‘microplastic’.

Toothpaste is a notorious source of ‘microbeads’.

Microplastic is simply defined as those bits of plastic waste smaller in length than 5mm. This famously includes ‘microbeads’ used in some cosmetics and toothpastes, but there’s also contribution from artificial fabric fibres and degraded bits of larger plastic waste. Because we often can’t see the microplastic with our naked eyes, it goes much more unheralded in contrast to the floating islands of waste bottles and packaging, but that invisibility makes it a more insidious monster.

We still don’t know much about the sources and pollutant pathways associated with microplastic. The United Nations Environment program suggest that cosmetic sources of microbeads have been a pollutant for at least the last 50 years but since then it has often been forgotten as a potential pollutant. In recent years researchers have observed river and ocean sediments in a number of global locations with high levels of microplastic accumulation, while a collaborative investigation between journalists and scientists has revealed that a significant proportion of tapwater in a wide range of urban settings contains measurable microplastic. It seems, then, that this is a problem of growing importance.

The impact for biology is also an emerging subject of study. Microplastic can accumulate either physically in organisms or the toxins generated as it breaks down can poison creatures all across the food chains. Ecologists regularly note the potential for pollutants and toxins to become more concentrated in species further up the food chain, and this is just as true for microplastics. In addition, the plastic compounds have the potential to adsorb other toxins and contaminants onto their surfaces; this mechanism of pollution delivery is poorly understood but considering that the smaller the plastic fragments the greater the proportion of surface area that could be utilised in this way, it could well play a role.

From a sustainability perspective, these plastic fragments could be a timebomb. Not only do they pollute water systems and potentially contribute to poisoning aquatic species, but the impacts could grow for years to come. Even if in the future we shift to a more sustainable model of consumption and production, and recycle the majority of the plastic we use, we will still have to deal with a microplastic legacy of our current plastic use. At present, we have only recycled or incinerated around 20% of our plastic waste meaning that the remaining 80% could disintegrate into fragments over time. It’s clear that understanding how this material enters our water systems and ecosystems is thus of paramount importance.

Microplastic particles on a beach. Image credit: NOAA

And here’s where geologists can play a role. River systems are a topic of interest and study for so many earth scientists, whether geochemists, hydrologists, or geomorphologists. Many geologists routinely sample rivers to analyse the amount of sediment within, or the chemical fluxes. Microplastic fits within the same areas of study; it has been described as a “structural” rather than chemical pollutant – which essentially means it forms part of the solid load of a river – just like regular sediment. Naturally, the physical properties of the plastic differ to sand or clay (the difference in density is particularly important), but the methods we could use to calibrate our microplastic models would be similar to those used to assess suspended or bedload in rivers.

Some scientists are already using these techniques, but much more work needs to be done to effectively understand the long term evolution of the fragments in natural waters. How, for example, do storms and floods affect the storage or mobilisation of microplastic in river sediments? Using hydrological tools to fingerprint the sources of microplastic might also help form a better picture of where exactly these pollutants enter the water systems, which still in many locations remains a mystery. Hydrological models incorporating microplastic transport would certainly help ecologists plan for the impact pollutants would have on aquatic species, and this is exactly what hydrologists could bring to the table.

The adsorption of chemicals to the surface of plastic is similar to other particles in the water flow – particularly colloids. Recent studies have shown that microplastic can adsorb heavy metals (another key set of pollutants) onto their surfaces, and thus deliver these pollutants to a range of species that might ingest the plastic. These are processes well understood by geochemists, offering a chance for the geochemistry community to collaborate with ecologists and conservation researchers.

As with a number of the issues standing in the way of achieving the Sustainable Development Goals, addressing microplastic pollution will require extensive cooperation between scientists of different stripes, policy makers, and polluters. A recent study suggests both that plastics from road wear by cars are the biggest contributor in parts of Europe and that sewage treatment efficiency is an important variable. Resolving these kind of complex infrastructure and ecological problems should certainly engage a cross-section of researchers.

Geologists can find their role in solving this problem as scientists, but importantly as regular citizens too. Limiting plastic use and advocating for recycling are already part of the arsenal of tools we can use to improve the sustainability of our lives; geologists shouldn’t forget that they can contribute in these ways too. Research is still ongoing to understand the range of products and plastics that either contain or form microplastic pollution, but we should all keep track of this research to ascertain how we can minimise our microplastic footprint. We need drinking water more than any other resource, and keeping it unpolluted by tiny plastic particles is an imperative.

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