Genuine Fake

What’s on your bucket list?
? See the Niagara Falls
? Watch the Northern Lights
? Cruise up the Amazon River

It’s hard to imagine that there will be any change to these extraordinary sights in a hundred or even a thousand years, but one such place may be gone before you are.
The Great Barrier reef which flanks the North East coast of Australia is our planet’s largest coral reef system and is the biggest single structure made by living organisms. While that makes it a marvel it is also what makes it mortal.

Great-Barrier-Reef

Because the survival of living structures is dependent on their surroundings they are vulnerable to changes in factors like temperature, food supply, salinity, predation and acidity.

coralatrisk

With warming waters and acidifying oceans it is no wonder that the world’s coral reefs are suffering. Since 1950, 19% of the coral reefs have been lost and a further 35% are threatened or in critical condition. However warming and acidification are disproportionate and so is the loss. Areas like the Caribbean have lost 80% of their reefs and face considerably more warming and a decrease in pH by the end of this century.

Hard coral reefs are made up of small colonial Anthozoans which convert carbon dioxide in the water into calcium carbonate skeletons. Many corals have a symbiotic relationship with zooxanthellae which give the corals their colour. The coral skeleton provides protection and anchorage to microscopic unicellular algae which, in return, photosynthesise providing the coral with nutrition. This mutualism results in the most marvellous and diverse ecosystems which provide a home to anemones, starfish, shrimp and many other species.

GreatBarrierReefcolourful

The sad thing is that this mutualism is mortal and becomes disrupted when either partner is adversely affected. Unfortunately, reefs are under attack from both sides. In my post, The Sea Butterfly Effect, I explained how the increase in atmospheric CO2 causes the oceans to become more acidic and how it decreases the availability of carbonate ions which shelled marine organisms need to form their skeletons. With the increase in anthropogenically produced CO2 we have surpassed the levels of acidity that corals flourish at, making it harder for them to lay down new skeleton. On the other side, the increase in warming is affecting the zooxanthellae which do not survive temperatures warmer than 29°C. Rising sea levels are also increasing the depths of the reefs allowing less light to penetrate making it harder for the algae to photosynthesise. Pollution and increases in suspended sediment also decrease the light that reaches the reefs.

You know how when white light hits a prism it splits into the colours of the rainbow, well the complete opposite is happening to our reefs. The combination of acidification, warming, sea level rise and pollution results in the phenomenon known as coral bleaching. Under stress conditions the coral expel the zooxanthellae and then starve.

coral-bleaching

Ultimately, it is human development along with overfishing that is causing the startlingly fast loss of this unique habitat. In reading some comments around the issue I found one sarcastic Sam who says “Never mind, we can use our old motor tyres for a home for the fish. They’re just as beautiful.” and while most people are disgusted by how much humans are impacting the planet, critism doesn’t help a stitch.

It is now, at the 11th hour, where a team of scientists have decided to see what they can do to ‘throw threatened reefs a lifeline’. Palumbi, a marine biologist at Stanford University in California along with other coral researchers around the world have become interested in a reef which thrives in temperatures which would kill most corals. Off the coast of the South Pacific island,  American Samoa, the lagoon hosts antler-like branching corals and huge mound corals.

Samoan reefs

What Palumbi and his team aim to do is harness the Samoan reefs’ ability to survive these harsh conditions and use it to create a hardy coral that has a chance of surviving the warming oceans. Starting this month, they aim to plant “the smartest future reef” they can imagine.

Collecting Samples For StudyTo determine which corals would make good transplant candidates they placed samples from a cool and a hot pool into controlled tanks and exposed them to temperatures of nearly 3°C above normal for four days. After this time all of the corals were bleached, but those that came from the hotter pools survived longer and had a higher expression of thermal-tolerance genes known to make heat-shock proteins and antioxidant enzymes.

Palumbi suggests that it is the genetic fitness and acclimatisation of the corals from the hotter pool allow them to better survive the environmental conditions. These heat-tolerant individuals also seem to survive transplants better. They plan to use experiments like these to find the fastest-growing and most heat-resistant corals for their smart reef. They will compare the growth of their smart reef to the growth of a second reef constructed from corals picked at random and see which survives better over the next few years.

The important things is that stress resistance developed through acclimatisation needs to be able to be passed on to offspring otherwise it will not be of use to future generations of coral. Another team based at the University of Hawaii have found that adult cauliflower corals (Pocillopora damicornis ), exposed to stress during brooding, produce larvae that are more resilient to high temperatures and low pH. This trans-generational protection is hypothesised to be due to epigenetic changes effecting gene expression. This team aim to cross-breed corals that have survived bleaching and then track the resilience of the offspring.

While for this type of smart-reef to work it is important to find a hardy coral, it is essential that the symbiotic algae are also stress tolerant. Fortunately the algae are shorter lived and therefore faster evolving than the coral host and other studies have already shown that they can pass on thermal tolerance to their offspring.

So far the research suggests that producing a smart-reef is possible, but is it a good idea? Their work will involve manipulating natural systems and essentially result in ‘human-assisted evolution’. We know that selective-breeding programmes can lead to genetic bottlenecks: the genetic variation is narrowed resulting in a decreased ability of the population to adapt to further changes. We also know that enhancing some traits can often come at the expense of other traits, such that heat-resistant corals may be less resistant to disease. We don’t know yet whether these trade-offs are worthwhile.

While some are completely against the idea of manipulating systems, sometimes it could be the only thing preventing the loss of an entire ecosystem.

Not only are coral reefs a beautiful sight, but some 500 million people depend on them in some way for food and income.

How do you feel about altering ecosystems and their ability to adapt to changing conditions?  Are these designer reefs genuine? Or fake?

Worlds-coral-reefs-at-risk

Want to know more about the state of reefs? This video gives an interesting, but sad perspective on their decline.

Coral reefs & climate change (full version) from Earth Touch on Vimeo.

Inspired by:
Mascarelli, A. (2014) Climate change adaptation: Designer reefs. Nature. 508:444-446.

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Don’t judge a fruit by its mesocarp!

The old saying goes ‘don’t judge a book by its cover’, but for anyone who’s studied a bit of botany the fruity twist will be appreciated. (Credit to Stephen Vander Wall)

The reason I criticise the judgement of outward appearances is because the two atypically pretty plants below are going to be the subjects of my attention this year and had someone cast them aside as unattractive I might not have such an interesting albeit ‘nerdy’ project to work on.

blog erica flowers

These two species are endemic to small areas in the Western Cape and are likely to have out-of-the-ordinary pollination systems as they are not attractive to the usual pollinators that we associate with Cape Fynbos.

Erica nabea and Erica occulta have not yet been studied and this leaves me with the urge to figure out what is pollinating them or if they are fertilising themselves.

E. nabea is found in the Outeniqua Mountains above George and Knysna and grows to about 1.5m in height. Its flowers are green and white and appear between May and August.

E. occulta is found exclusively on a small patch of limestone on the Southern Agulhas Plain near Pearly Beach. It flowers between August and October and its flowers are hidden in a mass of hairy leaves. It is extremely localised and its <6 km² distribution is threatened by the alien invasive, Acacia cyclops and the potential construction of a nuclear power plant.

Blog eric distribution

Unfortunately, removing the threat of the competing acacia and preventing the construction of a nuclear power plant may, in this case, be an easier feat than rescuing this species as its population is so small that it could be on the verge of extinction. The population consists of about 50 individuals and their genetic diversity and their subsequent ability to adapt to change may be very low.

As part of my Honours project I am going to look at the micro-satellites of these two species to assess the level of heterozygosity in their populations. The heterozygosity of the micro-satellites is a fancy way of saying that I am going to investigate the genetic variation of the plants in the population.

But, some species are adapted to being selfers (they fertilise their ovules with their own pollen). These species don’t need to invest in making colourful flowers or lots of nectar to attract pollinators. E. nabea is an Adelopetalum meaning unseen or secret and E. occulta is named from occultus meaning secret or hidden. Maybe these two species are adapted to selfing and hopefully by the end of my experimenting and observing I will be able to understand what these plants are doing so secretly. I also hope that they still have enough genetic diversity to see them through the imminent climate change as it will be sad to see such unique plants go extinct.

A topical, tropical time bomb

Deforesting our lungs WWF

Based on a recent article by Laurence, Sayer and Cassman about
“Agricultural expansion and its impacts on tropical nature”

The world is currently hurtling along in an attempt to be bigger, better, faster and wealthier than ever before. However, if we carry on at the rate we’re going, we’ll have to convert an area the size of Canada into cropland by 2050.

By 2011 the world’s population exceeded 7 billion and it is expected that we will reach 11 billion by the end of this century. With this exponential growth comes the ever increasing demand for fuel and food and of course the land to produce them on.

As the price of oil skyrockets, so do food prices – driving increasing efforts to produce cheaper sources of fuel. 

foodoilprice

Bio-fuels are made by converting organic matter produced by living organisms into convenient energy containing substances. For example, one can produce bioethanol by fermenting starch rich crops and extracting the alcohol. Bio-fuels are a potential solution to our looming energy crisis, as while coal and oil take geological time to produce, crops grow comparatively instantly and are therefore ‘renewable’.

The best place to grow crops for these bio-fuels is in the tropics. The tropics are warm and wet all year round, ideal for encouraging growth, not to mention that land is a fraction of the price compared to land in developed countries. However, the tropics are home to rain forests and are hot-spots of biodiversity. Many of the species living in these forests are endemic and endangered.

The diversity we stand to lose due to forest clearing is phenomenal, let alone the species we are yet to discover.

rainforestbiodiversity

Tropical biodiversity: (A) tree pangolin from Gabon; (B) tree fern from north Queensland; (C) Corybas orchid from Papua New Guinea; (D) gold dove from Fiji; (E) caterpillar from Suriname.

Bio-fuel production takes a lot of space. Huge plantations take the place of natural forest leaving a monoculture of soybean, oil-palm or the like.

deforestationandplantation

Deforestation for plantations: (A) industrial oil palm plantation in Sumatra, Indonesia; (B) clearing of native forest for industrial wood-pulp production in Sumatra; (C) small-scale farmers in Gabon; (D) aftermath of slash-and-burn farming in the central Amazon.

Clearing large tracts of land poses challenges to conservation as it causes fragmentation and isolation of forest patches. Forest species need migration and dispersal corridors to ensure their survival and maintain genetic diversity. Modified land is not useless to conservation, however. It provides important foraging land and stepping stones to other forest patches. The challenge to conservation is when this modified land in between healthy forest patches is overly transformed or too large. Perhaps an important study would be to determine the threshold size and quality where species stop being able to cross modified land.

The argued solution is to intensify farming practices on already modified land. Increasing the productivity of each hectare should in theory decrease the spread into surrounding hectares. To satisfy the demand for food and fuel there is a ‘yield-gap’ which needs to be filled. Laurence, Sayer and Cassman offer advanced farming technologies as the mechanism to fill this gap.

These technologies should provide better pest management, crop rotation and crop-specific fertilisers among others. Studies have also found that 10-40% of produce in developing countries is lost after harvest, during storage and transport. Improved facilities and refrigerated-transportation could decrease food wastage dramatically.

Genetically modified crops are another possible solution. Plants can be bred to produce greater proportions of protein or to be pest and drought resistant and so contribute to closing the yield-gap.

The problem here is that the poorer farmers do not have access to these improved technologies and simply taking over the landscape with big corporations and their fancy equipment will only open a Pandora’s box of  further problems. Tropical farmers also cannot afford to buy new seeds each year which is often the case with genetically modified crops which are only viable for one season.

Too much fertilizer can also cause problems though. Excess nitrogen causes eutrophication in rivers and has knock on effects to the health of surrounding ecosystems.

What is the solution then?

fix

If I knew, I would probably be the next Wangari Maathai, but for now I can only say that perhaps it is a delicate combination of all the possible solutions that will be the answer.

Perhaps well-managed, multi-use landscapes can be compatible with conservation while still providing food and fuel for a growing world. Perhaps Eco-certification, incentives for good practice and subsidies for technology will help to get us there.

The important thing is that environmental strategies must be in line with current political, economic and social reality. There is no one size which fits all solution that we can enforce across the tropical board. The problems experienced by oil-palm farmers in Sumatra will be different to those faced by sorghum farmers in the Congo.

The main issue is still, how do we fill the yield-gap? I think we need to tackle the gap from both sides. Be less greedy to decrease demand to make the gap smaller and then be intensive instead of extensive to decrease the spread of cropland and destruction of rain forests.

We also better be investing in perfecting harnessing other forms of renewable energy. Solar power is not cheap enough yet to replace coal and oil. Once we can harness and store solar power, there will be no need for growing crops for biofuel. We also better be thinking out the box. Imagine we could irrigate the Sahara desert with desalinated sea water. That would certainly take the pressure off the tropics.

Ultimately we  need to do something NOW to prevent the topical, tropical time bomb from exploding in our faces.

Reference:

Laurence, W.F., Sayer, J. and Cassman, K.G. (2014) Agricultural expansion and its impacts on tropical nature. Trends in Ecology and Evolution. 29(2):107-116.

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