The University of Southampton

Category: Group A – Taylor

If you are in Assignment Group A, load your blogs here

Plants Revealed to be More Efficient at Higher CO2 Levels

Posted on by Erin Blandford

As we enjoy a varied diet of carbohydrates, proteins and fats, for plants it is the gas carbon dioxide (CO2), water and sunlight (figure. 1).

Figure. 1 Pedunculate Oak Tree; a temperate plant species that could be impacted by changing atmospheric conditions.
Figure. 1 Pedunculate Oak Tree in sunlight (Lind).

It is not just CO2 use which is made more efficient at elevated CO2 levels, water efficiency is greater as less water is lost from leaf pores; stomata. FACE (Free-Air CO2 Enrichment) experiments with soybean show that leaf pore conductance is not adapted to elevated CO2 but rather maintain decreased conductance. Furthermore, this increase in water efficiency is consistent between the leaf and canopy levels (Leakey et al, 2009).

 

It was also thought that higher CO2 levels lead to increased efficiency of nitrogen, a mineral required for growth, as plants grown at these levels do not have as much nitrogen present. These high CO2 grown plants also have a greater biological mass than those grown at normal CO2 conditions. However these CO2 levels where not found to affect levels of biological mass attained over plant lifetime which indicates that an accelerated period of growth that used up nitrogen reserves (Coleman et al, 1993). Increased CO2 levels are thought to contribute to increased uptake of nitrogen by plant roots rather than increased plant efficiency regarding nitrogen. Further FACE experiments at three separate forest locations showed that increased biological mass corresponded to increased nitrogen uptake from the soil. However this is limited to areas where nitrogen soil supply exceeds demand and is therefore unlikely to be seen in all plants worldwide (Finzi et al, 2007).

 

These FACE experiments are advantageous as they allow CO2 to be applied to a specific area of a wide range of ecosystems from desert to tropical forest. Trees as tall as 25m can be used in these experimental plots which can be as large as 30m in dimeter (Norby and Zak, 2011).

 

Figure.1 Atmospheric carbon dioxide (CO2) levels from 1950-2010 (IPCC, 2013)
Figure.2 Atmospheric carbon dioxide (CO2) levels from 1950-2010 (IPCC, 2013)

Scientists have been documenting rising atmospheric CO2, which is associated with planetary warming, for almost 70 years now, since 1950 (figure. 2). It is widely accepted that this change in CO2 has arisen from human industrialisation. While it seems that plants can positively cope with this change this conclusion must not be taken at face value and further studies must be undertaken.

 

 

 

  • Coleman, J.S., McConnaughay, K. D. M and Bazzaz, F. A. (1993). Elevated CO2 and Plant Nitrogen-Use: is reduced Tissue Nitrogen Concentration Size Dependent?. Oecologia. 93, 195-200.
  • Drake, B. G., Gonzalez-Meler, M. A and Long, S. P. (1997). More Efficient Plants: a Consequence of Rising Atmospheric CO2. Ann. Rev. Plant. Physiol. 48, 609-639.
  • Finzi, A. C., Norby, R. J., Calfapietra, C., Gallet-Budynek, A., Gielen, B., Holmes, W. E., Hoosbeek, M. R., Iversen, C. M, Jackson, R. B., Kubiske, M. E, Ledford, J., Liberloo, M., Oren, R., Polle, A., Pritchard, S., Zak, D. R., Schlesinger, W. H and Ceulemans, R. (2007). Increased in Nitrogen Uptake rather than Nitrogen-Use Efficiency support higher rates of Temperate Productivity under Elevated CO2. PNAS. 104 (35), 14014-14019.
  • IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
  • Leakey, A. D. B., Ainsworth, E. A., Bernacchi, C. J., Rogers, A., Long, S.P and Ort, D. R. (2009). Elevated CO2 Effects on Plant Carbon, Nitrogen and Water Relations: six important lessions from FACE. Journal of Experimental Botany. 60 (10), 2859-2876.
  • Lind, J. © Photo of Pedunculate Oak Tree. Available: http://www.arkive.org/pedunculate-oak/quercus-robur/image-A20783.html. Last accessed 20th March 2017.
  • Norby, R. J and Zak, D. R. (2011). Ecological Lessons from Free-Air CO2 Enrichment (FACE) Experiments. Annual Review of Ecology, Evolution and Systematics. 42. 181-203.

[480 words]



Plants are losing their jobs… FAST!

Posted on by Jacob Harper
Figure 1: Destruction of plant habitat from palm oil production.
Figure 1: Destruction of plant habitat from palm oil production.

So, the boss tells you the company’s going through a bit of a shake-up due to the current market conditions and needs a ‘more efficient’ workforce. He apologetically explains that you and Tim down the hall… are doing a one-person job. Plant extinctions might be happening in much the same way… for the moment.

 

The rate of extinction is too damn high, and it’s driven primarily by human activities creating habitat loss, introduced exotic species and global warming. Using even the most conservative estimates, it’s thought we’re currently experiencing the 6th mass extinction in Earth’s history1. Previous events include the one that took out the dinosaurs. It’s estimated that we’re losing species at 1000-10000 times the background rate (extinction rate if humans weren’t around)2. For plants specifically, 21% of species are considered threatened with extinction according to ICUN red list criteria3 and less species equals less diversity.

 

But does losing biodiversity in ecosystems matter? Can the same amount of just one species not be as successful? One of the first studies to test this was performed in the Ecotron4,5, sadly not a planet saving robot, but a laboratory with completely controllable sealed environments. Simply put, they found an increase in mean biomass (functioning) with increasing diversity. Similarly scientists running an unrelated 11 year grassland experiment in Minnesota realised that their squares of grass maintained at different levels of diversity would be perfect for investigating this question6,7. They also found higher productivity with increased plant diversity and further encountered increased stability of the ecosystem in response to drought. But these experiments took place in one location, can this be repeated across the world? The Biodepth Project8 did just that, monitoring controlled grasslands in eight different European countries. Once again, increased productivity with greater diversity was observed overall. So, these microcosm experiments seem to be telling us that if we lose diversity through extinction it will have a negative effect on the functioning of whole ecosystems.

 

Figure 1: A diagram showing the predominant curves found when plotting a measure of ecosystem functioning (y-axis) against species diversity (x-axis).
Figure 2: A diagram showing the predominant curves found when plotting a measure of ecosystem functioning (y-axis) against species diversity (x-axis).

 

Where does redundancy fit into this? Take a look at Figure 2. The straight line running through the middle of A, B and C depicts a situation where every species makes a unique contribution; you’re better with IT, Tim down the hall is better with report writing. However, what’s found in the majority of research9 is the saturated curve at the top of each graph. Here we see an initially slow decline in functioning as most species that die off have one doing something similar to take its place; you and Tim basically do the same job. This is called species redundancy. But once we run out of non-unique species, we suddenly spiral into a fast and dramatic decline in functioning.

 

What’s worrisome about this? We are currently not sure where exactly on this saturated curve most of our ecosystems sit. Can we rely on species redundancy for a long time to come or are we at the edge of the precipice about to destroy the productivity of the natural world. I’d rather not find out.

 

 

References:

  1. Ceballos, G., Ehrlich, P.R., Barnosky, A.D., García, A., Pringle, R.M. and Palmer, T.M. 2015, ‘Accelerated modern human–induced species losses: Entering the sixth mass extinction’, Science Advances, 1 (5): e1400253.
  2. Chivian, E. and Bernstein, A. (eds), 2008, Sustaining life: how human health depends on biodiversity. Oxford University Press, Oxford.
  3. Kew, R.B.G. 2016, The state of the world’s plants report–2016, Kew: Royal Botanic Gardens.
  4. Naeem, S., Thompson, L.J., Lawler, S.P., Lawton, J.H. and Woodfin, R.M. 1995, ‘Empirical evidence that declining species diversity may alter the performance of terrestrial ecosystems’, Philosophical Transactions of the Royal Society of London B: Biological Sciences, 347 (1321): 249-262.
  5. Naeem, S., Thompson, L.J., Lawler, S.P., Lawton, J.H. and Woodfin, R.M. 1994, ‘Declining biodiversity can alter the performance of ecosystems’, Nature, 368 (6473): 734-737.
  6. Tilman, D. and Downing, J.A. 1994, ‘Biodiversity and sustainability in grasslands’, Nature, 367 (6461): 363-365.
  7. Tilman, D., Wedin, D. and Knops, J. 1996, ‘Productivity and sustainability influenced by biodiversity in grassland ecosystems’, Nature, 379 (6567): 718-720.
  8. Minns, A., Finn, J., Hector, A., Caldeira, M., Joshi, J., Palmborg, C., Schmid, B., Scherer-Lorenzen, M., Spehn, E. and Troumbis, A. 2001, ‘The functioning of European grassland ecosystems: potential benefits of biodiversity to agriculture’ Outlook on Agriculture, 30 (3): 179-185.
  9. Cardinale, B.J., Matulich, K.L., Hooper, D.U., Byrnes, J.E., Duffy, E., Gamfeldt, L., Balvanera, P., O’Connor, M.I. and Gonzalez, A. 2011, ‘The functional role of producer diversity in ecosystems’, American journal of botany, 98 (3): 572-592.


Plant adaption to changing climate through studying global scale response experiments – FACE (Free Air Carbon dioxide Enrichment)

Posted on by Jade Lemm

Jade Lemm

 

For the last 400,000 years plants have been adapted to low Carbon dioxide (CO2) of approximately 180ppm (parts per million) up until the Anthropocene era. However low CO2 was not always the case, up until the end of the Phanerozoic era concentrations were suggested to be minimal of 100 times higher current Anthropocene era CO2 (Kasting, 1987). In this current era CO2 has been seen to be rising at an ‘unprecedented rate’ from 1750 of 31% from sources natural and anthropogenic but the dramatic increase can be detected firstly from the industrial revolution (Steffen et al, 2015). These green plants such as forests are part of terrestrial sinks taking up 120 GTC (Giga Tonnes Carbon) per year dependant on location and time of year (Hartmann, Tank & Rusticucci, 2013). The time of year is important as an annual flux in CO2 is indicated by figure 1 showing the change in vegetative seasonality. Plants photosynthesize and draw the CO2 down in the summer but in the winter plants die back causing high CO2 concentrations shown by figure 2 (Gore, 2006).

 

co2-flux

Fig 1. – The increase of CO2 over time showing the displacement of seasons (Gore, 2006).

seasonal-co2-flux

Fig 2. – Change in CO2 over the seasons due to plant photosynthesis (Gore, 2006).

 

It has been debated on a global scale of how terrestrial and marine species would adapt to the rate of CO2 increase as it indicates to be a similar outcome to the Phanerozoic era. For the terrestrial green plant species past data over the 1900’s show that plants were adapted to higher CO2 makes higher plant respiration rates (Wullschleger, Ziska & Bunce, 1994). To adapt to these levels of high CO2 green plants use an enzyme called ‘Rubisco’ but is not an efficient plant as it slows water and nutrients. However, genetic engineering methods are still looking into enhancing this for global future food crisis as 50% demand increase is predicted (Whitney, Houtz & Alonso, 2011). The only way to confirm whether terrestrial plants can adapt to global changing CO2 is to study the effects in controlled environments such as Free Air Carbon dioxide Enrichment (FACE). FACE provides global scale responses from open air natural conditions with releasing controlled CO2 from pipes relying on wind to disperse it. This enables the study of modelling for future CO2, the increase of CO2 under these conditions have provided different effects on different species (McLeod & Long, 1999). For example, seeds of rice provided a yield growth increase of 5-7% under conditions of 550ppm for future conditions, compared to wheat at the same future conditions showed an increase of 27% with a further increase of 3% up to 650pmm (Ainsworth & Long, 2005). But these experiments all depend on the environment that they are placed in as it is all achieved by natural dispersal and planting time, the plants were only successful if early planting was achieved with the correct temperature and moisture. This varied at locations so studies in Australia would have to monitor the crops more carefully compared to Arizona (Mollah, Norton & Huzzey, 2009). However, more research is needed in this still unknown area to quantify the future.

 

References

Ainsworth, E.A. and Long, S.P., 2005. What have we learned from 15 years of free‐air CO2 enrichment (FACE)? A meta‐analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2. New Phytologist, 165(2), pp.351-372.

Gore, A., 2006. An inconvenient truth: The planetary emergency of global warming and what we can do about it. Rodale.

Hartmann, D.L., Tank, A.M.G.K. and Rusticucci, M., 2013. IPCC fifth assessment report, climate change 2013: The physical science basis. IPCC AR5, pp.31-39.

Kasting, J.F., 1987. Theoretical constraints on oxygen and carbon dioxide concentrations in the Precambrian atmosphere. Precambrian research, 34(3-4), pp.205-229.

McLeod, A.R. and Long, S.P., 1999. Free-air carbon dioxide enrichment (FACE) in global change research: a review. Advances in ecological research, 28, pp.1-56.

Mollah, M., Norton, R. and Huzzey, J., 2009. Australian grains free-air carbon dioxide enrichment (AGFACE) facility: design and performance. Crop and Pasture Science, 60(8), pp.697-707.

Steffen, W., Broadgate, W., Deutsch, L., Gaffney, O. and Ludwig, C., 2015. The trajectory of the Anthropocene: the great acceleration. The Anthropocene Review, 2(1), pp.81-98.

Whitney, S.M., Houtz, R.L. and Alonso, H., 2011. Advancing our understanding and capacity to engineer nature’s CO2-sequestering enzyme, Rubisco. Plant Physiology, 155(1), pp.27-35.

Wullschleger, S.D., Ziska, L.H. and Bunce, J.A., 1994. Respiratory responses of higher plants to atmospheric CO2 enrichment. Physiologia Plantarum, 90(1), pp.221-229.

 

Word count: 497



Climate Change IS happening, and it’s set to starve the planet… (The opposite of FAKE NEWS!)

Posted on by Anonymous

With the large scale funding cuts of the Environmental Protection Agency in the USA, the current rapid rates of climate change and CO2 release show no hope of stopping.

But seeing as though plants breathe using CO2 (through the process of photosynthesis), and use carbon in their growth, surely the increased amounts of CO2 being pumped into our atmosphere is a good thing for plants?  As studies have shown; perhaps not…

Plants require very specific environmental conditions to function efficiently, and any changes in these conditions can be detrimental.  Although it has been shown that increased CO2 initially causes an increase in the rate of photosynthesis and growth of leaves and roots (Taylor et al 1994), generally, in the long-term, the stimulation of photosynthesis is actually suppressed!

This is mainly due to negative effects on the plants function, such as the build-up of excess starch (sugars) in leaves via increased photosynthesis, hindering breathing of CO2 via pores; called the stomata (Makino & Mae 1999), and increased CO2 also causes the stomata to partially close (Singh 2009), resulting in an inability to respire efficiently (Ryan 1991).

The mechanism for respiration in a plant leaf, through the stomata.
The mechanism for gas exchange in a plant leaf, through the stomata.  Source: Understanding Evolution

The failure to respire efficiently can cause the death of many food crops globally that are vital to feeding our populations!

Increased environmental CO2 also results in global warming due to increased reflection of the Sun’s radiation back to the Earth’s surface; and a temperature increase of 2-3⁰C over the next 30-50 years (IPCC 2007) is predicted to cause problems for our crops.  For example, warmer temperatures affect plants mainly when they are developing, and this has been shown to reduce the numbers of our food crop plants by 80%-90% (Hatfield & Prueger 2015), having dire consequences for our food supplies!

The global change in surface temperature from 1901-2012. A worrying trend that is set to worsen... Source: National Snow & Ice Data Center
The global change in surface temperature from 1901-2012. A worrying trend that is set to worsen… Source: National Snow & Ice Data Center

Climate change is also set to increase the frequency of extreme weather events (Rosenzweig et al 2001). With increased storms and flooding drowning plants in some areas, and in other areas increased drought, resulting in a lack of water for plants to function with, which they rely heavily on for processes such as photosynthesis, vital for growth and survival.  The equation for photosynthesis is shown below, in case you have forgotten…

 

The equation for photosynthesis, showing how carbon dioxide and water are transformed into oxygen and sugars through the light energy from the sun hitting the chlorophyll pigments in the plants cells.
The equation for photosynthesis, showing how carbon dioxide and water are transformed into oxygen and sugars through the light energy from the sun interacting with the chlorophyll pigments in the plants cells.

 

With increasing global temperatures, drought affected areas will increase from 15.4% to 44.0% by 2100 (Li et al 2009) – resulting in less land to grow crops, which will be disastrous for our food security, along with the fact that the number of suitable growing days per year for our crops will decrease by 11% by the year 2100 (Mora et al 2015)!

A sunny day on a Californian beach? Not exactly… This is Californian farmland suffering from a severe drought – completely unusable!
A sunny day on a Californian beach? Not exactly… This is Californian farmland suffering from a severe drought – completely unusable! Source:  New York Times

 

With the saying “Feed the World” becoming more and more poignant, our future looks bleak, as we are set to have less food security per person than ever before due to the detrimental effects that climate change will have on plant function. Also, plants not only provide food, but are also at the heart of our medicines and resources! So maybe Donald Trump ought to reconsider his views on climate change before threatening his new healthcare system before it has begun.

Word Count: 500

 

References:

Hatfield, J. and Prueger, J. (2015). Temperature extremes: Effect on plant growth and development. Weather and Climate Extremes, 10, pp.4-10.

IPCC, (2007). Climate Change 2007: Impacts, Adaptation and Vulnerability. New York: Cambridge University Press, p.17.

Li, Y., Ye, W., Wang, M. and Yan, X. (2009). Climate change and drought: a risk assessment of crop-yield impacts. Climate Research, 39, pp.31-46.

Makino, A. and Mae, T. (1999). Photosynthesis and Plant Growth at Elevated Levels of CO2. Plant and Cell Physiology, 40(10), pp.999-1006.

Mora, C., Caldwell, I., Caldwell, J., Fisher, M., Genco, B. and Running, S. (2015). Suitable Days for Plant Growth Disappear under Projected Climate Change: Potential Human and Biotic Vulnerability. PLOS Biology, 13(6), p.e1002167.

Rosenzweig, C., Iglesius, A., Yang, X., Epstein, P. and Chivian, E. (2001). Climate change and extreme weather events – Implications for food production, plant diseases, and pests. Global Change & Human Health, 2(2), pp.90-104.

Ryan, M. (1991). Effects of Climate Change on Plant Respiration. Ecological Applications, 1(2), pp.157-167.

Singh, S. (2009). Climate change and crops. 1st ed. Berlin: Springer, pp.5-6.

Taylor, G., Ranasinghe, S., Bosac, C., Gardner, S.D.L. and Ferris, R. (1994). Elevated CO2 and plant growth: cellular mechanisms and responses of whole plants. Journal of Experimental Botany, 45, pp.1761-1774.



Could crop and tree diseases completely alter the world we live in today?

Posted on by Holly Moser

Imagine Winnie the Pooh without One Hundred Acre Wood, Robin Hood without Sherwood Forest or Baloo without his prickly pears.

This cartoon was created to illustrate how all the trees were chopped to stop a 'killer fungus' (Adams, 2012)
This cartoon was created to illustrate how all the trees in the One Hundred Acre Wood were chopped down to stop a ‘killer fungus’ (Adams, 2012)

Back to the real world 

Acute oak decline Symptom: Profuse stem bleeding (Forestry Commission, 20170.
Acute oak decline
Symptom: Profuse stem bleeding (Forestry Commission, 2017).

The facts are that oaks are being decimated by acute oak decline (Forestry Commission, 2017), pears by fire blight (Johnson, 2000) and the Woodland Trust estimates that the UK could lose 130 million ash trees (Woodland Trust, 2017). These plants are part of our culture and economy but imagine how much worse it would be if you lived in the developing world and your staple diet was at risk.

Rice, the basic diet of half of the world’s population (FAO, 2013), is under threat from a serious disease called rice blast. Silicon is rice’s natural ‘knight in shining armour’ shielding it from this pathogen. Elevated CO2 levels are expected to decrease the plants silicon production, leaving rice vulnerable to its arch enemy and reducing overall yield (Elad and Pertot, 2014).

 

Invasion of the north

Scientists expect some pathogens such as Phytophthora cinnamomi  one of the world’s most invasive species to shift northwards due to warmer and wetter winters increasing the chance of overwinter survival in areas that are currently unsuitable (Burgess et al., 2017).

Although drier summers should have a counteracting effect, trees that have already been infected by P.cinnamomi are less likely to recover due to a reduced ability to take up water by rotting roots and increased drought stress (Burgess et al.,2017).

A map of the areas where P.cinnamomi already exists and the areas that may become more or less suitable for the invasion of P.cinnamomi with regards to future climate change.
A map of the areas where P.cinnamomi already exists and the areas that may become more or less suitable for the invasion of P.cinnamomi with regards to future climate change (Burgess et al., 2017).

Researchers are working against the clock to create new fungicides and develop disease resistant crops but these interventions appear to have some worrying knock on effects.

For example, researchers from the University of Exeter thought they might have a solution to ash dieback by breeding from older, resistant trees. However, it was recently discovered that that these older trees produce fewer chemicals to ward off the deadly emerald ash borer (University of Warwick, 2017). A double strike from ash dieback and emerald ash borers could wipe out ash in the UK!

Illustration of the Emerald ash borer and the damage it can cause to ash trees (Clark, 2013).
Illustration of the emerald ash borer and the damage it can cause to ash trees (Clark, 2013).

The news is not all bad

Although Baloo may lose his prickly pears, not all diseases are expected to increase with climate change and he may gain bananas. One disease expected to decrease in severity and frequency reducing the impact it has on global yield is black sigatoka a disease which decreases the leaf area in bananas reducing photosynthesis (Elad and Pertot, 2014 & Ploetz, 2001).

So where does that leave us?

There are still many gaps in plant disease research involving mechanisms of infection, resistance and the affect on plant function. There are also many unanswered questions- could a decrease in one disease kick off the invasion of another? Such factors make it impossible to predict the exact change to our landscape and crops. But the simple answer to my question is yes. Unless plant disease research achieves some major breakthroughs the chances are that our landscape will look very different and we may need to develop a taste for new foods.

 

 

References

Adams, 2012. Cartoon: One Acre Wood. Available from: http://www.englishblog.com/2012/10/cartoon-one-acre-wood.html#.WNMBBG-LTIX  [Accessed on: 16/03/2017].

Burgess, T.I., Scott, J.K., McDougall, K.L., Stukely, M.J.C, Crane, C., Dunstan, W.A., Brigg, F.,Andjic, V., White, D., Rudman, T., Arentz, F., Ota, N. and Hardy G.E.ST.J., 2017. Current and projected global distribution of Phytophthora cinnamomi, one of the world’s worst plant pathogens.  Global Change Biology; 23: 1661-1674.

Clark, P., 2013. Health and Science: The emerald ash borer’s domino effect on human health. Available from: http://www.washingtonpost.com/wp-srv/special/metro/urban-jungle/pages/130514.html [Accessed on: 21/03/2017].

Elad, Y. and Pertot, I., 2014. Climate change impacts on plant pathogens and plant diseases. Journal of crop improvement; 28 (1): 99-139.

FAO, 2013. FAO statistical year book 2013: world food and agriculture. FAO statistical year books, Rome, FAO: p.132. Available at: http://www.fao.org/docrep/018/i3107e/i3107e.PDF [Accessed on: 22/03/2017].

Forestry Commission, 2017. Acute Oak Decline. Available from: https://www.forestry.gov.uk/acuteoakdecline [Accessed on: 21/03/2017].

Johnson, K.B. 2000. Fire blight of apple and pear. The Plant Health Instructor. DOI: 10.1094/PHI-I-2000-0726-01. Updated 2015.

Ploetz, R.C. 2001. Black sigatoka of banana: The most important disease of a most important fruit.  The Plant Health Instructor.  DOI: 10.1094/PHI-I-2001-0126-02. Available from: http://www.apsnet.org/publications/apsnetfeatures/pages/blacksigatoka.aspx [Accessed on: 22/03/2017].

University of Warwick, 2017. Ash dieback- insect threat to fungus- resistant trees. Available from: https://phys.org/news/2017-01-ash-diebackinsect-threat-fungus-resistant-trees.html [Accessed on: 16/03/2017].

Woodland Trust, 2017. Protecting landscapes. Available from: https://www.woodlandtrust.org.uk/visiting-woods/tree-diseases-and-pests/what-we-are-doing/protecting-landscapes/ [Accessed on: 21/03/2017].

Word Count: 494



Is Global Environmental Change endangering plants essential for life?

Posted on by Anonymous

When looking at the bigger picture, extinction is a very common event with an estimated 99% of all fauna and flora species to have graced the Earth have been and gone (Barnosky et al., 2011). The majority of these occur during ‘mass extinctions’ of which there have been 5 to date. However evidence is staking up suggesting we are entering an era of the sixth; the difference lying with this extinction being anthropogenically driven.

It is now widely accepted (with obvious exceptions) that human activities are to blame for the increased release of greenhouse gases contributing to the rising rate and extent of climate change experienced.  Predictions put the temperature increase by the end of the century somewhere between 1.5 and 5.8°C (Rosenzweig et al., 2001), and a rise in carbon dioxide from 350 parts per million (ppm) to between 525 and 810 ppm (Bisgrove & Hadley, 2002)

images rtemagicc_floods-bangladesh-23204-small-jpg

Figure 1&2 are examples of both extremes droughts and floods.

When focusing on plants, there are some advantages of a warmer climate with higher concentrations of carbon dioxide. The combination of heat and abundance of CO2 for photosynthesis will increase growth rates and prolong growing seasons. Milder winters with fewer frosts will also allow for better conditions. However that’s about as far as the advantages go. Other than photosynthesis impacts are seen affecting respiration, growth, development phases and reproductive processes (Hartwell Allen et al., 1996).

One area of biggest worries in the future is the increase in size and number of extreme weather events seen globally, mainly droughts and flooding (EPA, 2017). In short, no water means no growth, too much water no growth. For example in America in 1988 and drought swept the nation and caused $3billion worth of crop to fail! Flooding also caused a similar level of damage to the US 4 years later covering a mere 11,000,000 acres (Rosenzweig et al., 2001)!

Changes seen to both habitat and atmosphere mean that plants will have to adapt and evolve to be able to remain in conditions that are getting progressively less favourable. If they cannot manage to adapt then they will not survive.

So looking back we can see that maybe in short term with small changes to both carbon dioxide and temperature it may benefit how plants function, but moving forward these changes create a variety of much larger issue for plants. Through extreme weather events and changing conditions and habitats plants adapt or die. Now relating back to the first paragraph, it might not be an issue for the Earth seeing as it always manages to survive setbacks. The problem is for humans as we only have one shot and cannot afford to become extinct, and we rely on plants for essentials like air and food. This shows the importance to us and the need to look after them as best we can, starting with the biggest problem facing them; climate change.

 

Word Count: 475

 

Barnosky, A., Matzke, N., Tomiya, S., Wogan, G., Swartz, B., Quental, T., Marshall, C., McGuire, J., Lindsey, E., Maguire, K., Mersey, B. and Ferrer, E. (2011). Has the Earth’s sixth mass extinction already arrived?. Nature, 471(7336), pp.51-57.

 

Bisgrove, R. & Hadley, P ., 2002. Gardening in the Global Greenhouse: The Impacts of Climate Change on Gardens in the UK. Technical Report, UKCIP, Oxford, UK.

 

EPA. (2017). Future of Climate Change | Climate Change Science | US EPA. Available at: https://www.epa.gov/climate-change-science/future-climate-change [Accessed 17 Mar. 2017].

 

Figure 1: Ghadyalpatil, A. (2017). Maharashtra announces Rs10,512 crore aid for farmers hit by drought. Available at: http://www.livemint.com/Politics/XMKAji99WJU6ULsfddE5qL/Maharashtra-announces-Rs10512-crore-aid-for-farmers-hit-by.html [Accessed 15 Mar. 2017].

 

Figure 2: FAO (2017). Floods : FAO in Emergencies. Available at: http://www.fao.org/emergencies/emergency-types/floods/en/ [Accessed 15 Mar. 2017].

 

Hartwell Allen Jr., L., Baker, J. and Boot, K., 1996. The CO2 fertilization effect: higher carbohydrate production and retention as biomass and seed yield.

 

Rosenzweig, C., Iglesius, A., Yang, X., Epstein, P. and Chivian, E. (2001). Climate change and extreme weather events – Implications for food production, plant diseases, and pests. NASA Publications.



Crops and Climate Change: the good, the bad and the ugly truth

Posted on by Anonymous

New Year, New Hope? But 2017 began with Britain being hit with a vegetable shortage!

 12

(Independent, 2017)                                                    (The Guardian, 2017)

But apart from halting our “clean eating” resolutions…..

Is a courgette shortage really the end of the world?

Well, probably not! But globally, food security is no laughing matter.

 And what is the cause you may ask? Climate change, of course!

The evidence for climate change is overwhelming.

The Earth’s average temperature has increased by 0.85°C between 1980-2012 (IPCC, 2014). This may seem insignificant, yet, it has severe consequences, such as the ice caps melting, sea levels rising and increased occurrence of extreme weather events (Overpeck and Cole, 2006).

3

Globally averaged combined land and ocean surface temperature (IPCC, 2014)

Humans are to blame.

Since the industrial revolution, burning of fossil fuels has increased emissions of carbon dioxide (CO2) and other greenhouse gases (GHGs) These GHGs act as a blanket, trapping energy in the atmosphere, causing Earth’s temperature to rise (IPCC, 2014).

4

Global Human CO2 Emissions, IPCC, 2014

The good?

Higher CO2 levels increase plant photosynthesis (Pospisilova and Catsky, 1999). Photosynthesis depends on an enzyme called Rubisco, which evolved at higher prehistoric CO2 levels, therefore has higher activity when CO2 increases (Bowes, 1996). This increases plant growth, thereby increasing crop yield, in a phenomenon termed “CO2-fertlisation” (Allen, 1990).

This is particularly pronounced plants categorised at C3 , which includes major crops such as rice, wheat and soybean. Increasing CO2 to 550pm causes 10-20% increase in C3 crop yield, but only 0-10% increase plants categorised as C4, which includes the crops maize and sorghum (Schmidhuber and Tubiello, 2007).

CO2 enters plants through stomata (plant pores), therefore, at higher CO2 levels the stomata need not open as often, termed reduced stomatal conductance. This decreases the amount of water lost through the pores in the process of transpiration, thereby increasing the water efficiency of the plants (Drake et al., 2007).

The bad?

So, is climate change good for plants if it causes increased growth and higher water efficiency? Well no, it was never going to be that simple…

Extreme weather events negatively impact food security, both directly by reduced yields from damaged crops but also indirectly by increasing the chance of landslides and soil erosion, thereby reducing the land available for agriculture (Cerri et al., 2007).

This issue is becoming more urgent as global population increases at an unprecedented rate, increasing the demand for food (MA, 2005).

Food security issues are not only concerned with the quantity of food but also the quality, as globally many people suffer from malnutrition (MA, 2005). Elevated CO2 decreases the zinc, iron, and protein content in wheat, barley, and rice (Myers et al., 2014).

 5

The two-fold effect of increased CO2 form increased carbon emissions; most likely the negative effect will outweigh the positive effect. 

The ugly truth

Unfortunately, it is predicted the losses will outweigh any gains from CO2 fertilisation.

Ultimately, lack of food could see increased prices for consumers in the developed world whilst the developing world will suffer with food shortage and malnutrition.

Lack of courgettes may seem a trivial matter but is it just one more sign that we getting closer to the tipping point of our planet’s ability to cope with climate change.

Word count: 499

References

Allen, L.H. Jr. (1990). Plant responses to rising carbon dioxide and potential interactions with air pollutants. J. Environ. Qual, 19: 15-34.

Bowes G. (1996) Photosynthetic responses to changing atmospheric carbon dioxide. pp. 387-407. In: N.R. Baker (ed.). Photosynthesis and the Environment. Advances in Photosynthesis, Vol. 5, Kluwer, Dordrecht

Cerri, C. E.P., Sparovek, G., Bernoux, M., Easterling, W.E., Melillo, J. M., and Cerri C. C. (2007). Tropical Agriculture and Global Warming: Impacts and Mitigation Options. Sci. Agric., 64(1): 83-89.

Drake, B.G., Gonzàlez-Meler, M.A. and Long, S.P., 1997. More efficient plants: a consequence of rising atmospheric CO2? Annual review of plant biology, 48(1): 609-639.

IPCC. (2014) Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. R.K. Pachauri and L.A. Meyer (eds.). IPCC, Geneva, Switzerland, pp. 151.

Millennium Ecosystem Assessment (2005). Ecosystems and Human Well-being: Synthesis. Island Press, Washington, DC.

Myers SS, Zanobetti A, Kloog I, et al. (2014). Rising CO2 threatens human nutrition. Nature. 510(7503): 139-142.

Overpeck, J.T. and Cole, J.E. (2006). Abrupt change in Earth’s climate system. Annual Review of Environment and Resources, 31: 1-31.

Pospisilova, J. and Catsky, J. (1999). Development of water stress under increased atmospheric CO2 concentration. Biologia Plantarum, 42: 1-24.

Schmidhuber, J. and Tubiello, F.N. (2007). Global food security under climate change. Proc. Natl. Acad. Sci. USA, 104(50): 19703-8.



How do you like your toast in the morning? Without the worry of food security?

Posted on by Imogen Vieten

80% of human calorie intake comes from 6 major crops including – maize, wheat and rice1. For all people, at all times to have physical and economic access to sufficient food needed for a balanced diet2–food security, the production and distribution of these crops is vital.

Present day representation of global vulnerability to food insecurity8. Explore scenarios of Greenhouse gas emissions and adaptation to climate change impacts on food security by clicking on the link: http://www.metoffice.gov.uk/food-insecurity-index/ Present day representation of global vulnerability to food insecurity3. Explore scenarios of Greenhouse gas emissions and adaptation to climate change impacts on food security by clicking on the image.

A growing human population increases pressure to enhance crop production. 1 billion ha of land will be converted by 2050 for agriculture, reducing absorption of atmospheric carbon dioxide by plants2 and restoration of gaseous balance in the atmosphere, with fewer plants to act as a CO2 ‘sink’.

Human induced climate change is negatively affecting ecosystems, crop yield and production. Since the industrial revolution greenhouse gas emissions have risen, with atmospheric CO2 levels currently at 406.42ppm4, meaning plants are growing in conditions not experienced for 26 million years5.

Impacts of future climate change are predicted to be severe, varying between regions, through changes in temperature, precipitation and increases in extreme weather events. Methods of crop production such as sustainable intensification are needed to increase yields and overcome threats to livelihoods and food security2.

Will increased CO2 result in higher crop yields?

During photosynthesis plants use CO2, water and light to produce oxygen and carbohydrates for growth. Efficiency of this depends on the enzyme Rubisco, which functions better in high CO2, shown experimentally to increase photosynthesis by 58%5. There is evidence that the number and size of individual cells increase in elevated CO26, showing species specific adaptive ability7,  indicating potential to increase crop yield. However other climatic stresses will have negative effects.

The temperature dependant action of Rubisco may become less efficient with rising global temperatures. Furthermore in the long term, plants can acclimatise as additional carbohydrates produced from photosynthesis cannot be used5.

During extended periods of high CO2 exposure the number of stomata- pores used in gaseous exchange in leaves, may decrease indicating that photosynthetic rate will too7.

How will crop production be affected?

For sustainable intensification sufficient water and nutrients8 are required, which will be threatened by increased extreme weather events- from drought affecting water supply to storms where heavy downpours can wash away top soil, reducing land fertility.

Threats to global productivity and changes in yield could have impacts worldwide8. If production decreases, prices of grain products and meat reliant on grain as a feedstock will increase8. Furthermore lower agricultural output, especially in the developing world, leads to lower incomes, with the poorest suffering the most.

High CO2 can decrease food quality with a decline in protein, nitrogen, zinc and iron concentrations in crops9, potentially causing adverse health effects, and necessitating consumption of greater quantities.

Securing the future

FACE (Free-air concentration enrichment) experiments expose crops to elevated CO2 to examine responses and adaptions of ecosystems. Research to develop climate resilient crop varieties to better cope with heat, drought and salinity is also being conducted.

By adapting farming mechanisms and increasing yield and tolerance of essential crop species to environmental extremes, can we ensure food security? Yes, the time to act is now!

 

Discover more about how farmers may adapt their practices to a changing climate in the video ‘Feeding Nine Billion’10

 

[499 Words]

References

  1. Campell, N,A., Reece, J, B., Urry, L,A., Cain, M,L., Wasserman, S, A., Minorsky, P, V., Jackson, R, B. (2015). Seed Plants. In: Wilbur, BBiology A Global Approach. 10th ed. Essex: Pearson. p707.
  2. Sunderland, T., Powell, B., Ickowitz, A., Foli, S., Pinedo-Vasquez, M., Nasi, R. and Padoch, C. (2013). Food security and nutrition: The role of forests. Center for International Forestry Research. Discussion Paper, p1-20.
  3. Met Office. (2017).Food Insecurity Climate Change. Available: http://www.metoffice.gov.uk/food-insecurity-index/. Last accessed 18th March 2017.
  4. CO2 (2017). Earth’s CO2 home page. Available: https://www.CO2.earth/earths-CO2-main-page. Last accessed 20th March 2017.
  5. Drake, B, G. and Gonzàlez-Meler, M, A. (1997). More Efficient Plants: A Consequence of Rising Atmospheric CO2?.Annual Review of Plant Physiology and Plant Molecular Biology. 48, p609-639.
  6. Taylor, G., Ranasinghe, S., Bosac, C., Gardner, S and Ferris, R. (1994). Elevated CO2 and plant growth: cellular mechanisms and responses of whole plants. Journal of Experimental Botany. 45 (Special Issue). P 1761-1774
  7. Long, S, P., Ainsworth, E, A., Rogers, A. and Ort, D, R. (2004). Rising Atmospheric Carbon Dioxide: Plants FACE the Future.Annual Review of Plant Biology. 55, p591-628.
  8. Nelson, G, C., Rosegrant, M, W., Koo, J., Robertson, R., Sulser, T., Zhu, T., Ringler, C., Msangi, S., Palazzo, A., Batka, M., Magalhaes, M., Valmonte-Santos, R., Ewing, M. and Lee, D. (2009). Climate Change: Impact on Agriculture and Costs of Adaptation.International Food Policy Research Institute. Available at: http://www.fao.org/fileadmin/user_upload/rome2007/docs/Impact_on_Agriculture_and_Costs_of_Adaptation.pdf. Last accessed 19th March 2017
  9. Myers, S., Zanobetti, A., Kloog, I., Huybers, P., Leakry, A., Bloom, A., Carlisle, E., Dietterich, L., Fitzgerald, G., Hasegawa, T., Holbrook, N., Nelson, R., Ottman, M., Raboy, V., Sakai, H., Sartor, K., Schwartz, J., Seneweera, S., Tausz, M. and Usui, Y. (2014). Increasing CO2 threatens human nutrition. Nature, 510, p139-142
  10. Fraser, E. (2014). Feeding Nine Billion Video 6: Climate Change and Food Security. Available: https://www.youtube.com/watch?v=cYq2elstFWQ. Last accessed 18th March 2017.


Rising temperatures threaten to drown our forests?

Posted on by Rory Smith
Will rising temperatures create wetter environments? More water means more trees though, right? (Source: YouWall).
Will rising temperatures create wetter environments? More water means more trees though, right? (Source: YouWall)

We all love the view and enchantment of a beautiful forest, at least I know I do. Forests are a place of majesty, exploration and inspiration. They are also arguably the most important vegetation zone on the planet (Myers, 1989).

I have spent the past four months exploring and hiking up as many trails as my legs would allow while staying in a wood cabin in the amazing Colville Forest, Washington. During my stay, I had a lot of time to think to myself and experience nature. I became inspired, inspired to inform others of the dangers that threaten a place I have grown to treasure and so many others hold dear.

Colville National Forest – a splendour of natural beauty (Source: USDA).
Colville National Forest – a splendour of natural beauty (Source: USDA).

Global warming and climate change:

Climate change, is the most pressing environmental concern of our time (Solomon et al., 2009).

Atmospheric carbon dioxide (CO2) levels have been rising since the industrial revolution, and temperatures have been rising ever since (Thuiller, 2007). Temperatures have risen 0.6oC since before the industrial revolution (Lawlor, 2005) but with this rising temperature comes many other changes to global climate (Jump and Penuelas, 2005).

One of the key changes in climate is a different rainfall pattern, regions closer to the equator will receive less rain and regions closer to the poles will receive more (Lawlor, 2005).

Source: Columbia Unviersity
Change in precipitation pattern (Source: Columbia University). 

Of course, a reduction in water for trees at low latitudes will produce negative effects, as trees need water to survive. So, surely an increase in water will be a good thing? Won’t more water result in more trees? It can’t do any harm, can it? Yes, yes it can.

Effects of high rainfall and flooding on trees:

Tree roots absorb oxygen (O2) and minerals from pockets of air in the soil (needed for healthy growth) (Kozlowski, 1986), but after an influx of water these air pockets become saturated and the soil compacted. This rapidly reduces O2 levels in soil and can severely reduce tree growth and even kill trees (Kozlowski, 1984; Kozlowski, 1986). These anaerobic (O2 absent) conditions can also cause the growth of harmful fungi, which can infect the tree roots with a range of diseases, potentially killing the trees (Stolzy and Sojka, 1984).

Why does this matter?

Trees are a vital sink of atmospheric CO2 (Canadell and Raupach, 2008), crucially combatting the effects of climate change by absorbing vast amounts each year. During a process called photosynthesis, plants leaves use light energy to convert CO2 and water into O2 and glucose (food). This is the process crucial to combat the effects on climate change.

Climate change is also altering the distribution of species (Fitzpatrick et al., 2008) and unlike animals, plants cannot migrate fast enough to track the changing climate of the future (Jump and Penuelas, 2005). Therefore, plants must withstand and adapt to future changes.

Not only is Colville National Forest at risk, many more breath-taking forests are at risk of the same effects. So, will forests adapt and continue to play an imperative role in the fight against climate change? Or will they perish?

The future is uncertain and this question remains to be answered.

 

Word Count: 500

References:

Lawlor, D.W., 2005. Plant responses to climate change: impacts and adaptation. In Plant Responses to Air Pollution and Global Change. Springer Japan, pp.81-88.

Solomon, S., Plattner, G.K., Knutti, R. and Friedlingstein, P., 2009. Irreversible climate change due to carbon dioxide emissions. Proceedings of the national academy of sciences, 106(6) pp.1704-1709.

Jump, A.S. and Penuelas, J., 2005. Running to stand still: adaptation and the response of plants to rapid climate change. Ecology Letters, 8(9), pp.1010-1020.

Thuiller, W., 2007. Biodiversity: climate change and the ecologist. Nature, 448(7153), pp.550-552.

Kozlowski, T.T., 1986. Soil aeration and growth of forest trees (review article). Scandinavian Journal of Forest Research, 1(1-4), pp.113-123.

Kozlowski, T.T., 1984. Plant responses to flooding of soil. BioScience, 34(3), pp.162-167.

Canadell, J.G. and Raupach, M.R., 2008. Managing forests for climate change mitigation. science, 320(5882), pp.1456-1457.

Stozly, L.H. and Sojka, R.E., 1984. Effects of Flooding on Plant Disease. In: Kozlowski, T.T. ed. Flooding and Plant Growth. London: Academic Press Inc. Ltd, pp. 221-241.

Fitzpatrick, M.C., Gove, A.D., Sanders, N.J. and Dunn, R.R., 2008. Climate change, plant migration, and range collapse in a global biodiversity hotspot: the Banksia (Proteaceae) of Western Australia. Global Change Biology, 14(6), pp.1337-1352.

Myers, N., 1989. The future of forests. The Fragile Environment: The Darwin College Lectures, pp.22-40.



Who Will Lift Simba now?

Posted on by Adrian Bailey

 

rafiki

If climate change persists at its current rate, then many animals will lose their homes, including that of the beloved Lion King mandrill, Rafikis’; the most recognisable silhouette of a tree ever seen. The iconic baobab tree, famous for its resemblance of an upside down tree, is under threat. In an arid, scrubland environment this species acts as a fundamental source of water, food and shelter for many animals, including the endemic lemurs of Madagascar.

Since travelling to South Africa at the age of nine, I remember many animals, but the only plant I can name and recognise is a baobab. With their thick, tall, bare trunks and root like branches, they are unlike any other plant. They don’t just possess an aesthetic appeal but are highly beneficial to biodiversity and the local and international community. Baobab fruit is highly nutritious, with its powder being rich in Vitamin C; perfect for anyone who is looking for a solution to wrinkles (well supposedly) (Schumann et al., 2012). In addition, it provides food, medicine, fibre, craft material and income to the local community in Africa (Sanchez, 2012). One potential use of the baobab tree is as a biofuel. This has already been tested with success and is shown to meet European and American biodiesel standards (Modiba et al., 2014).

So, baobab is a plant providing many benefits to people, with the potential to reduce fossil fuel use if it becomes commercially viable as a biofuel. What is the problem?

Two words…CLIMATE CHANGE!

 

The Tree of Life
The Tree of Life

Due to longer periods of drought from a slight increase in temperature and increasingly infrequent rainfalls, seedling establishment is poor, resulting in low recruitment rates (Venter & Witkowski, 2013). Through the last 25 years of the 20th century, annual rainfall decreased by 1.5%, suggesting that future desertification throughout Africa is inevitable. This places more pressure on seedling settlement and potentially the future population (Geist & Lambin, 2004). Once mature baobabs can withstand prolonged drought, with incredible water storage capabilities within their swollen bellied trunk. Seedlings, however do not have this quality. So to overcome the negative impact caused by climate change, human interference may be necessary. Furthermore, mature trees are beginning to show symptoms of disease and therefore there is a greater reliance on recruitment, which has already appeared under pressure.

Many conservation efforts have already taken place but are they actually conserving trees for the future? Researchers have discovered, via spatial distribution modelling, that only a very low percentage of the present distribution is predicted to remain a suitable habitat for the baobab in the future (Sanchez et al., 2011). As a result of this shift in distribution, the present protected areas are unlikely to actually impact the future population. Therefore, we are wasting our energy on lost causes, where instead it should be focused at future locations (Vieilledent et al., 2013).

The true potential of the baobab is finally being realised, but is it too late? Fingers crossed it is not.

References

Geist, H. & Lambin, E., (2004), “Dynamic Causal Patterns of Desertification”, BioScience, Vol. 54, No. 9, pp: 817-829

Modiba, E., Osifo, P. & Rutto, H., (2014), “Biodiesel production from baobab (Adansonia digitata L.) seed kernel oil and its fuel properties”, Industrial Crops and Products, Vol. 59, No. n/a, pp: 50-54

Sanchez, A, C., (2012), “The status of baobab tree populations in southern Malawi: implications for further exploitation”, Forests, Trees and Livelihoods, Vol. 20, No. 2-3, pp: 157-173

Sanchez, A, C., Osbourne, P. &  Haq, N., (2011), “Climate change and the African baobab (Adansonia digitata L.): the need for better conservation strategies”, African Journal of Ecology, Vol. 49, No. 2, pp: 234-245

Schumann, K., Wittig, R., Thiombiano, A., Becker, U. & Hahn, K., (2012), “Uses, management, and population status of the baobab in eastern Burkina Faso”, Agroforestry Systems, Vol. 85, No. 2, pp: 263-278

Venter, S, M. & Witkowski, E, T, F., (2013), “Where are the young baobabs? Factors affecting regeneration of Adansonia digitata L. in a communally managed region of southern Africa”, Journal of Arid Environments, Vol. 92, No. n/a, pp: 1-13

Vieilledent, G., Cornu, C., Sanchez, A, C., Pock-Tsy, J. & Danthu, P., (2013), “Vulnerability of baobab species to climate change and effectiveness of the protected area network in Madagascar: Towards new conservation priorities”, Biological Conservation, Vol. 166, No. n/a, pp: 11-22

 

Word count: 493