Archive for the 'Earth Sciences' Category

Let’s save Punta de Choros

Chile is in front of one of the most important challenges in the next years: to deal with an increased demand of energy. Naturally, many options are proposed by different “players”. But two big forces are in the final battle. By one hand, one consortium is a big defender of hydroelectric power, installing several dams. In second place, another group is claiming that nuclear energy is the only option for satisfy chile’s demand of energy.

In the meanwhile, many small thermoelectric (gas, oil, or coal) power plants are being installed. One of them is placed near to a region known as “Punta de Choros”. The international audience is not aware of the upcoming damages that this power plant could do to this region. The following video (in spanish and with english subtitles) explain some of the probable damages. It is enough to say that Punta de Choros is an extremely important region for biologists and ecologists. It harbors important species and is a natural Marine reserve.

The big problem here also is that, as in many other issues, Chilean scientists are not being listened at all. Many scientists are claiming that wind energy is the best option for our country: it is clean, affordable for a country with economic stability, suitable to increase the energy’s demands, and also feasible considering the abundance of wind in several places in our country. Enemies state that the costs of wind energy are very high (without serious studies), and that this energy is not suitable. Well… let’s see. The following figure shows the energy produced in our country, in the context of wind energy:

A recent article in Science (Vol. 329, pp. 382-385) also reviews the proposed alternative to thermal and nuclear plants: flooding of valleys and rivers in the Patagonia, losing precious ecosystems and biodiversity. It is very dissapointing to see how chilean authorities don’t want to listen to scientists and engineering, and to see wind energy and other clean energies (such as solar) as a real option.

Global Biodiversity Indicators at-a-glance

ResearchBlogging.orgI really wanted to talk about this article before. A few weeks ago, it was published in Science a work by an extensive work by a high number of researchers, focused in the review and discussion of indicators of global indicators of biodiversity. Citing the article, in 2002 world leaders committed, through the Convention on Biological Diversity, “to achieve by 2010 a significant reduction of the current rate of biodiversity loss”.

Now, 2010 has been named the International Year of Biodiversity. And a team reported in this article, numbers and trends showing the current state of several indicators of biodiversity, grouped into four main categories: indicators of state, pressure, response and benefits.

The indicators of state are related with the state of biodiversity in terms of species and ecosystems. Eight indicators show a decline. For example, the Living Planet Index (mean population trends of vertebrates) show a continuous decline since 1970. The Red List Index, indicating the risk of extinction of mammals, birds, amphibians and corals, also show a decline. Other indicators are Forest Extent, Coral Reef Condition and Water Quality Index.

Indicators of pressure on biodiversity are more related with difficulties upon the improvement of biodiversity. One example is the Exploitation of Fish Stocks, which exhibits a great increase. All the indicators of pressure (Ecological Footprint, Nitrogen Deposition Rate, Alien Species in Europe, and Climate Impact Indicator) show an increase.

Although the numbers are discouraging, some hope arises when we look at the positive numbers. Indicators of response are increasing, and the authors show some data related with improvements in biodiversity. For example, at least 16 bird species extinctions were prevented by conservation actions during 1994-2004. Also, deforestation in Amazonia decreased, protected areas increased and several countries have policies and agreements related with the prevention of spread of alien species.

This post is not intended to be a review of the article. Instead, it offers a view at-a-glance, a general commentary of the article. I advice to all the readers of this post to read the article and to visit the webpage of the Convention on Biological Diversity, where you can download more information about the mission and goals for this year and for the future.

In words of the authors of the article, “our results show that, despite a few encouraging achievements, efforts to address the loss of biodiversity need to be substantially strengthened”.

References

Butchart, S., Walpole, M., Collen, B., van Strien, A., Scharlemann, J., Almond, R., Baillie, J., Bomhard, B., Brown, C., Bruno, J., Carpenter, K., Carr, G., Chanson, J., Chenery, A., Csirke, J., Davidson, N., Dentener, F., Foster, M., Galli, A., Galloway, J., Genovesi, P., Gregory, R., Hockings, M., Kapos, V., Lamarque, J., Leverington, F., Loh, J., McGeoch, M., McRae, L., Minasyan, A., Morcillo, M., Oldfield, T., Pauly, D., Quader, S., Revenga, C., Sauer, J., Skolnik, B., Spear, D., Stanwell-Smith, D., Stuart, S., Symes, A., Tierney, M., Tyrrell, T., Vie, J., & Watson, R. (2010). Global Biodiversity: Indicators of Recent Declines Science, 328 (5982), 1164-1168 DOI: 10.1126/science.1187512

Secretariat of the Convention on Biological Diversity (2010) Global Biodiversity Outlook 3., & Montréal, 94 pages. (2010). Global Biodiversity Outlook 3 Convention on Biological Diversity

Science predicted the Chile’s Earthquake

I am finally back, repairing some of the damages in our labs. The situation in Chile is not good. The deaths are raising slowly, but continoulsy, over 800 people now. Also, some data regarding thousands of missing people is also of great concern.

Regarding to science, several laboratories have reported serious damages, including lost of data, expensive equipment (you must consider that, due to the location of Chile, far from the manufacturers, equipments and reagents cost three or four times more expensive than in USA or Europe).

The observations and predictions (at a glance)

It is surprising that researchers had predicted the earthquake almost two years ago [1]. Teachers always say to students “nature is unpredictable; you can’t know where an earthquake will occur”. But technology advances, and together with mathematical modeling and observation, just like Darwin did in his travel to Chile almost 170 years ago, describing the earthquake of 1835 [2], researchers can formulate hypotheses about when, and how strong an earthquake will occur.

Ruegg and coworkers published a paper in “Physics of the Earth and Planetary Interiors” (Ruegg JC, 175:78–85, 2009). The team made observations in a range from 1996 to 2002, focusing in the area from Constitución to Concepción, since no major earthquakes occurred in that space since 1835 (described by Darwin). They measured the displacement of the plate (more exactly, the velocity of the movement). The results (at a big glance, since I am not a geologist) showed that coastal regions had a higher velocity compared with regions in the Andes area. Assuming that no major earthquakes released the accumulated force since 1835, a deficit of horizontal displacement of 10 m will have accumulated.

To Ruegg and coworkers, this could mean, in a worst case scenario, “that the southern part of the Concepción–Constitución
gap has accumulated a slip deficit that is large enough to produce a very large earthquake of about Mw = 8.0–8.5”.

What happened in Chile?

This February 27, at 3:34 am (Chile’s time), an earthquake with a magnitude of 8.8 in Ritcher scale occurred in a site very close to Cobquecura, located between Concepción and Constitución (see map below). The plates moved 8 m, and since Ruegg and coworkers calculated a 10 m of slip deficit, either the calculations are overestimated or the earthquake should have been even worse.

Figure 1. Earthquake and areas affected. Notice the location of the epicenter, just as predicted by Ruegg and coworkers.

Nonetheless, the prediction of Ruegg and his team is shocking. They were right about the epicenter and magnitude. The final phrase of the abstract is: “… in a worst case scenario, the area already has a potential for an earthquake of magnitude
as large as 8–8.5, should it happen in the near future”.

Interesting Data

Earthquakes in Chile show a striking regularity: every almost 17 years, a major earthquake (above 8 in Richter scale) occurr. Even more, the majority of the most destructive earthquakes ocurred in the chilean summer:

Figure 2: Major earthquakes in Chile since 1906. The box around 1939 and 1943 shows that the average (1941) was considered to calculate the years between the events (between 1922 and 1941, and between 1941 and 1960). 50% of the events occurred in summer or beginning autumn.

Conclusions

An obvious conclusion for our country, Chile, is the following: scientific observations can assist to make predictions about the most probable sites of a future earthquake, including information about the magnitude. Ideally, a global network across the identified seismic gaps in Chile (one at the north, one near to Valparaiso, one located between Concepción-Constitución and one near to Valdivia, epicenter of the greatest earthquake in the last 200 years) and some other regions , could help to be better prepared for a new earthquake. I don’t know of such an approach is being used in other seismic regions on Earth.

1. Ruegg, J., Rudloff, A., Vigny, C., Madariaga, R., de Chabalier, J., Campos, J., Kausel, E., Barrientos, S., & Dimitrov, D. (2009). Interseismic strain accumulation measured by GPS in the seismic gap between Constitución and Concepción in Chile Physics of the Earth and Planetary Interiors, 175 (1-2), 78-85 DOI: 10.1016/j.pepi.2008.02.015

2. Richard A. Kerr (2010). Did Darwin Help Predict Chilean Quake? Science Now

ResearchBlogging.org

This post was chosen as an Editor's Selection for ResearchBlogging.org

The ring of life


ResearchBlogging.org

I was really surprised, due to my lack of knowledge in too many areas of life sciences, that our history, the history of all species, from bacterias to humans, it is not like a tree. Usually we think about evolution as a tree, where some species have developed and give rise to a new, improved one (and I seay improved because Darwin’s view of evolution states that non-improved species should be eliminated in the process, which is fairly logic).

I am not familiar with the representation of evolution in dendograms and some other types. But a recent paper in Nature [1] teached me that, in fact, the evolution of the species cannot be represented as a tree. The right representation should be a ring. And I am far from understand the reasoning behind that statement, but it sounds right. When you have several species in a tree, and two of them get togheter, the two branches guided by that species are joined, closing that branches and creating a new one. Now, think about the origins of life. Surely not so many species should exists at that time; so, a few species are creating a very small tree of life. So, if two species from that “primordial” tree are joined, you create a ring, where the “joining point” is specifically the event in which the two species got together. But, the question remains: what events can account for such a joining? James Lakes states that an early prokaryotic endosymbiosis, between a clostridum and an actinobacterium, accounts for such event and created a plaform for the evolution of the eukaryotic life.

Some years ago, Lake presented an article in Nature [2] explaining that a genome fusion was the event responsible for the rise of the eukaryotic life. I remembered a discussion in my class, when I was an undergraduate student, regarding the issue that some eukaryotic genes were related to one prokaryotic lineage, and some others were related to another lineage. The analysis of Lake and Rivera showed that a ring structure can easily explain that discrepancy (or, in other words, the hypothesis that a genome fusion event between two prokaryotic species explain the rise of eukaryotes): informational genes of eukaryotes are derived from Archaea, and operational genes are derived from Bacteria.

It seems a good start. These two works provides interesting views about evolution of eukaryotes. But some questions remains, and are proposed by Lake itself. For example, can really the endosymbiosis be the only mechanisms explaining the ring structure? Maybe it is easier to have just two species joining that several species exchanging genes and, by an unusual mechanism, evolving until create a new organism harboring informational and operational genes from two specific lineages. But, why we cannot observe such endosymbiotic organisms? Lake presents the example of a prokaryotic consortium, Chlorochromatium aggregatum, as the only near example to an endosymbiosis between prokaryotic species. Could we be able to create an exclusively prokaryotic endosymbiosis in vitro? That would be interesting. If we are consistent with the notion of “don’t believe in what you can’t see”, we should be willing to explore others explanations for the rise of eukaryotic life.

[1] Lake JA (2009). Evidence for an early prokaryotic endosymbiosis. Nature, 460 (7258), 967-71 PMID: 19693078

[2] Rivera MC, & Lake JA (2004). The ring of life provides evidence for a genome fusion origin of eukaryotes. Nature, 431 (7005), 152-5 PMID: 15356622

Time to wake up?

Recently, a series of articles in Nature [1-3] described new perspectives about the climate crisis. The problem shows when you have to predict a scenario. Usually, researchers make descriptions and simulations about the outcome of the climate status using computational calculations, and they are able to simulate even thousand of years. They can simulate the development of the increase in the Earth’s temperature, CO2 concentration, and so on.

Well, the issue is: researchers had considered that a specific amount of CO2 could be accepted as reasonable in the atmosphere. Raising this concentration, we would expect the global warming to increase rapidly and then, we would see global changes. That amount was considered as 550 p.p.m. Then, researchers started to discuss about whether 550 p.p.m. would be too high. And the consequence was to determine the limit in 450 p.p.m. That was the dominant idea. Until now. In this articles in Nature [1-2], data and facts are provided to question that number. Obviously, these facts are not new. But we have here a comprehensive view about the situation. Briefly, new simulations allow us to evaluate the evolution of the climate status if a 450 p.p.m. of CO2 is achieved. The problem is that several simulations predict a dark outcome: the CO2 levels would keep high thousands of years. If you ask to someone: “How many years do you think the CO2 levels will keep high?”, the people would think, at most, 100 or 200 years. The main view is, if we stop emitting CO2 production, the levels will start to decrease, in a linear fashion. But the predictions tell us the opposite: even in 3000 years, CO2 levels will be high. Also global temperatures stay high.

More extreme scenarios, for example, 1000 p.p.m of CO2, are discouraging [2]. It seems that a limit of 350 p.p.m. is needed, according to some researchers [1]. A new global movement called 350.org, has been created, and the next October 24 has been claimed as the International Day of Climate Action. You can see a video here:

Of note, we are now above the 350 p.p.m. limit. A paper published in this issue of Nature [3], describes the perspectives of greenhouse-gas emissions if we want to keep the climate under a 2 ºC limit of increase in the temperature. It is likely that, under the actual scenario, we will raise the global warming above the “2 ºC” limit.

The question is: considering that, according to the simulations, it seems obvious that it is too late to keep the CO2 concentration under a safe amount, how are we going to proceed? We need to put a great effort in the study of technologies to avoid a risk to the human kind. For example, important cities should be relocated, we will need research about food technologies, water recovering and recycling, and technologies to build environments, houses and devices to live in safe and comfortable conditions.

When still some people are denying the existence of global warming and the need of stop the raising of CO2 concentrations, it is too late? Do we need to finally wake up? I strongly suggest to read these articles and to visit 350.org to more info.

References

[1] Monastersky, R. A burden beyond bearing. Nature, 2009; 458:1091-1094.

[2] Schneider, S. The worst-case scenario. Nature, 2009; 458:1104-1105.

[3] Meinshausen, M. et al. Greenhouse-gas emission targets for limiting global warming to 2 ºC. Nature, 2009; 458:1104-1105.

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