Australian rodent first mammalian victim of climate change

Bramble-cay-melomy

Tucked away on a small island off the coast of Queensland, Australia, the rat-like animal would have stared up at you with dark, beady eyes from the safety of some scattered shrubs.  No more than 15 centimeters long, the rodent would have been covered with light red fur, its tiny ears tucked tightly against its head, its pale underbelly barely visible.  You would have probably noticed the odd tail, as long as its body and lumpy with scales.

You may have seen this mosaic-tailed rat, melomys rubicola, had you traveled once upon a time to Bramble Cay, a small island built upon a the Great Barrier Reef.  But no longer.  After a fairly exhaustive search using traps, cameras, and searches on foot, Australian scientists have pronounced with confidence that the melomys is likely extinct [1].  The probable cause?  Evidence suggests dramatic weather conditions in the region combined with rising sea levels due to anthropogenic climate change  While a faint glimmer of hope remains that a small colony may still exist on poorly studied region of Papua Guinea, this is likely the first of many mammals to fall victim to the complex weather systems created by global warming.

The future, now

Why should we care?  Some will immediately sense the emotional connection: those cute little eyes and ears a victim of shameless human expansion across the globe.  And I don’t believe this sentiment can be overstated in these times, when we are moving farther and farther away from understanding our connection to the environment the effects of our industry on it.

But there is more to this loss than dealing with accomplice’s guilt.  The present weather systems bombarding Bramble Cay and their effects on the local ecosystem play out our future in fast-forward.  The island rests only 3 or 4 meters above sea level, leaving it susceptible to any slight changes in climate.  Whereas global sea levels have risen 20 centimeters over the last century, the oceans have risen at twice the average rate near Bramble Cay.  As a result, the area of the island consistently above high tide has shrunk since 1998 from 9.8 to 6.2 acres, eliminating the spread of vegetation, low-lying rock overhangs, and 97% of available habitat for the melomys.

As a group of scientists from the Department of Environment and Heritage Protection and the University of Queensland thoroughly documented the island, they found flattened, dead sedge along the coastlines, erosion, and the loss of soft substrate along rock formations.  All these signs point to dramatic weather systems recently hitting the cay.  In 2005, Tropical Cyclone Ingrid blasted the island, destroying up to half of all vegetation by 2011.  Harsh winters during the same time also brought more severe storms through the area.  Increased cyclonic activity near Queensland has already been associated with intensity in the La Nina cycle, which occurs with higher global mean sea surface temperatures due to anthropogenic global warming.  The melomys didn’t stand a chance given the loss of the vegetation and habitat.

“The key factor responsible for the extirpation of this population was almost certainly ocean inundation of the low-lying cay, very likely on multiple occasions, during the last decade, causing dramatic habitat loss and perhaps also direct mortality of individuals,” writes Gynther et al [1].  Such an explanation points to resilience, or the lack thereof: as sea levels rise, ecosystems near the coast or on islands cannot survive such severe storms as easily.

Here it is straight: human-induced global warming leads to changes in El Nino/La Nina oscillations leads to more severe storms leads to dramatic punishment to nearby ecosystems.  The melomys was caught in the middle.  All this happened quite quickly due to the low elevation of Bramble Cay, but this is an omen of what is in store for more heavily populated coastal regions as sea levels continue to rise and storms intensify.

Hope in Papua New Guinea

Australian scientists placed 900 small-mammal traps, set up 60 cameras, and combed the island for any sign of the mammal.  Usually these efforts turn up something, so the lack of a sighting indicates extinction.  But there may still be hope.  Some scientists believe the melomys living on Bramble Cay originated from the Fly River delta region of Papua New Guinea just to north, a less explored habitat that could be housing the last remnants of the species.  The scientists have recommended exploration of this area (if funding is available, of course).

The melomys is the first but not the last.  I never knew of this little creature before news of the search for their existence, but now the rodent serves as another reminder that the effects of global warming are happening now.  Scientists believe the finality of extinctions like these can be prevented if more resources are used to identify at-risk regions and relocate wildlife, not to mention reducing greenhouse gas emissions as quickly as possible.  The success of such a mission usually rests with finding enough money from politicians and governments who see the urgency of such pursuits.

References

Gynther I, Waller N, and Leung LK-P. “Confirmation of the extinction of the Bramble Cay melomys Melomys rubicola on Bramble Cay, Torres Strait: results and conclusions from a comprehensive survey in August-September 2014.” Unpublished report to the Department of Environment and Heritage Protection, Queensland Government, Brisbane, 2016.

Howard BC. “First mammal species goes extinct due to climate change.National Geographic, June 14 2016.

Figure Credits

Figure of Bramble Cay melomys courtesy of Ian Bell via Wikipedia

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Oil spill cleanup secrets of Gulf Coast bacteria

gulf-oil-spill-720x445

I’m excited to put up a guest post by Shayna Keyles this week! Shayna Keyles is a multi-discipline writer, editor, and marketer based in Oakland, California. You can reach her at skeyles@gmail.com or follow her on Twitter at @shaynakeyles.

This article was originally published by GotScience.org, which translates complex research findings into accessible insights on science, nature, and technology. Help keep GotScience free! Donate or visit our gift shop. For more science news subscribe to our weekly digest.

Bacteria have played a large role in cleaning up the Gulf Coast after the 2010 Deepwater Horizon oil rig explosion, but it is just now becoming clear how helpful these microbes have been. Microbiologists sequenced DNA from native Gulf bacteria and discovered genetic properties that make some of these microbes so well suited to the job of cleaning up oil.

The smallest (and largest) cleanup crew

Scientists noted the proliferation of native bacteria just weeks after the rig explosion began to leak 4.1 million barrels of oil into the Gulf of Mexico. The bacteria appeared to consume both the oil and some of the dispersants used to help break up the spill.

A research team from the University of Texas at Austin, led by Brett Baker, assistant professor in the Department of Marine Science, and Nina Dombrowski, a postdoctoral researcher in Baker’s lab, set out to discover why bacteria were able to proliferate in such conditions. They collected live samples from the site of the spill and sequenced the genetic material from numerous bacteria in order to study bacteria’s genetic potential for cleaning an oil spill.

The bacteria that Baker and his team studied are typically not abundant until they are exposed to oil, at which point the populations tend to grow. This indicates that the bacteria are consuming the oil. The research team wanted to decode which parts of the oil were being consumed and how. Oil is a complex material, consisting of hundreds of chemical compounds, but the scientists focused their efforts on two compound groups that the bacteria may be responding to.

“Oil is extremely complicated, but it has two major compounds: alkanes, which are relatively easy for bacteria to break down, and aromatic hydrocarbons, which are much trickier to get rid of,” says Dombrowski.

“Polyaromatic hydrocarbons (PAHs) are among the most toxic in oil and are among the most abundant,” Baker tells GotScience. “We focused on the way bacteria in the spill break those down.”

They found that many bacteria are more equipped to handle PAHs than previously thought: Many of the bacteria the team studied have hydrocarbon-degradation genetic pathways, in addition to the alkane-degradation pathways that were found in all of the bacteria the group examined.

Alcanivorax, for example, is a type of bacteria that scientists already recognize as an oil eater: It is known for consuming alkanes. But the group found genetic evidence that the microbe was capable of breaking down the PAHs the spill had left behind. The team was also able to add new types of bacteria, such as Neptuniibacter, to the list of oil eaters.

A community oil spill effort

A key point to take away from this study’s findings is that a flourishing bacteria community is capable of greatness. Not only did the genetic sequencing uncover how individual bacteria respond to oil, but it also suggested that the combined efforts of a large bacterial community could have an enormously positive impact on a spill area.

There may be hundreds of complex compounds found in an oil spill, but there are also hundreds of hungry microbes in the water ready to feast on alkanes and PAHs. And it seems that’s not all they’re hungry for: Some of the bacteria seem to feed on the dispersants used to clear away the oil spill.

Dombrowski notes, however, that not all dispersants are microbe friendly. As we gain a better idea of the genetic composition of these bacteria and how bacteria communities cooperate, we can develop bacteria-friendly dispersants that help humans and bacteria work together harmoniously. “We need to make sure our response to a spill doesn’t interfere with this natural response,” she explains.

Of course, it should be noted that we cannot rely on bacteria to clean up our water for us—we shouldn’t be spilling oil in the first place. But when these tragic events do occur, we can count on our bacterial brethren to help us out.

References

Dombrowski N. “Reconstructing metabolic pathways of hydrocarbon-degrading bacteria from the Deepwater Horizon oil spill.” Nature Microbiology, 16057, 2016.

Photo Credits

Figure of oil spill courtesy of Andreas Teske at the University of North Carolina – Chapel Hill

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The greening of Vancouver

Aqua_Tower_thermal_imaging

Aim a normal camera at a city skyline and you’ll likely snapshot a bustling panorama of skyscrapers and the incessant activity that energizes city-dwellers.  But point a thermal camera at the same cityscape and you’ll see a different form of energy: hot yellows and reds pouring out of towering glass buildings and other structures.

Residential and commercial heating is one of many energy demands that cities around the world are trying to make more efficient.  Glass skyscrapers are especially poor at trapping heat and these reflective monoliths were built during past decades of growth and expansion that cared less about energy conservation.  But it’s not just rethinking heating: composting, sewage recycling, car-sharing, and many other innovative ideas could reinvent city living and decrease carbon emissions at the same time.  As described by a new article in Science, no city is pushing harder for the lead in this type of transformation than Vancouver.

Green Goals

Vancouver city officials have challenged themselves to become the greenest city on the planet.  What are the numbers behind this declaration?  The city hopes to reduce energy use and emissions from buildings by 20% by 2020 and require all new structures built after 2030 to have no emissions.  This is a courageous goal, one that will need not only loads of renewable energy but also ingenious changes to how cities fundamentally operate.

Green is by no means a new color for the city just north of Seattle in Western Canada.  The city officially labeled climate change as a threat in 1990 (what was your city doing back then?), and its reliance on hydropower has lowered its carbon emissions beyond any other major city in North America.  Even now, city planning entices citizens to live in the central part of the city, increasing population density and pushing down required resources per capita.

But more changes are on the horizon, bringing us back to the giant skyscrapers blazing red on a thermal image.  More than two-thirds of Vancouver’s energy is used to heat buildings, just one indication that eco-friendly population densities and some renewable hydropower is not enough.  Rethinking basic city processes and reinventing the new norm is the great hope in Vancouver.  Here are just some of the ideas underway concerning energy efficiency, waste management, and traffic control in the City of Glass.

  1. Getting tough on trash.  How well do you separate your garbage and recycling?  Do aluminum cans sometimes find their way into your paper bin?  If so, warning stickers and violation fees would find their way to your doorstep if you lived in Vancouver.  Garbage inspectors now patrol the streets, checking for correct waste separation.  But it’s about more than keeping paper and metals apart.  The city found that 40% of landfill methane, mostly coming from organic waste, was escaping into the atmosphere and contributing to greenhouse gas emissions.  Inspectors are now handing out green bins for citizens to toss out scraps like meat, bones, and rotten leftovers.  The waste ends up in composting facilities to both reduce the amount of organics finding their way to landfills and to provide soil for regional farmers.  The inspectors also hope to be more than hand-slappers.  “It’s our job to do face-to-face education,” Jez Figol, one of many inspectors who talks to residents about how to decrease their footprint.
  2. Heating from sewage. Instead of dumping sewage water, plants in Vancouver now extract the heat from the wastewater flow to reuse to heat buildings.  Wastewater runs through a giant strainer (imagine your kitchen colander on steriods) to remove large particles, then passes by a heat exchanger as big as a semi truck.  This exchanger pushes the heat back through pipes that run through many city buildings, providing hot water to about 6000 residences from one plant.  All from sewage waste!
  3. Rethinking transportation.  Traffic congestion plagues almost every city and Vancouver is jumping on the bandwagon of creating bike-friendly traffic patterns and easy car rentals.  Bike lanes have popped up across the city to encourage more people to pedal to work.  Car-sharing has also taken off, as city officials predict that every rental car removes up to 11 private cars from being on the road.  Finally, the city has incentivized mass transportation, which has put a strain on the system because of its rising popularity.  All of these improvements has made traffic control one of Vancouver’s biggest success stories so far, as the city as already met its goal of cutting kilometers driven per person by 20%.

The challenges of being first

Vancouver officials outlined most changes in a 2011 action plan to reduce emissions 80% by 2050.  Currently, emission have been reduced by 7% in about 4-5 years due to changes like the ones listed above.

Unfortunately, not all parts of Vancouver’s greenification are evolving as successfully.  Most skyscrapers are still leaking heat because they are nearly impossible to renovate.  “Glass curtain-wall buildings are terrible and expensive to retrofit,” says Sean Pander, who manages the Vancouver green building program.  The only option is to slowly tear down old buildings and build new ones with stricter codes for energy efficiency, which takes a long time.  The City Council has offered small financial incentives for voluntary improvements by private businesses, but the details, like where to relocate employees temporarily, have not been fleshed out.

There are other issues looming on the horizon that could muddle Vancouver’s green plans.  Most of these relate to conflicts of interest between the city and provincial or national level.  For example, provincial officials will soon determine whether an oil pipeline and natural gas export facility can be built  close to Vancouver’s port, which would make emissions skyrocket.  Such a conflict illustrates the unique challenge that city officials face when greening their cities, playing proud promoter of green policies to the public while working diplomatically with the other parts of Canadian government to allow them to succeed in their mission.

And then there are the paths to sustainability that only citizens can achieve.  On average, cities require a land footprint about 200 times larger than the city’s actual area.  Cities can enact as many innovative policies as they like, but this footprint can be significantly reduced only through individual citizen choices: what they eat, when they turn off their lights, how high they turn up their AC, and what renewable energy policies they support.  Cities can do their part, and it is tremendously hopeful to hear about officials that are so passionate to take the lead in going green.  Let’s hope citizens can match this passion and action with their own will and innovation to help turn cities green forever.  In the meantime, Vancouver continues to push the green innovation edge farther along, hoping others will follow.

References

Weiss, K.R. “Vancouver’s Green Dream.” Science352(6288), 918-921, 2016

Figure Credits

Thermal photo of Aqua Tower in Chicago courtesy of Jim D’Aloisio via Wikipedia

 

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Surfing the polar front: how black carbon reaches the Arctic

Black carbon aerosol is carbon dioxide’s darker accomplice.  Not as well known as the atmospheric molecule that has defined our global climate crisis, black carbon still plays a role in amplifying warming trends, particularly in the Arctic.  But how did it get there?  Experimental studies continue to find more of this light-absorbing pollutant in the Arctic than global climate models predict, keeping its origin a mystery.

A new article [1] in Scientific Reports provides a partial answer by improving the resolution of climate models and illuminating how small-scale phenomena can play a huge role in global weather patterns.  The conclusions get us closer to understanding just how our fossil fuel industry is forever changing the planet beyond 66 degrees N.

Two possibilities, zero answers

The incomplete combustion of fossil fuels, biomass, or agricultural waste creates black carbon.  These tiny bits of leftover carbon are classified as particulate matter smaller than 2.5 microns in diameter (PM2.5) and are associated with a host of negative health effects like heart or lung disease.  Developing countries like India or China are struggling mightily to manage local black carbon levels that are rapidly rising.

Unfortunately, degrading human health is not the only danger.  According to the EPA, black carbon is the most effective PM2.5 at absorbing solar energy, capturing a million times more sunlight per unit mass compared to carbon dioxide.  Now, imagine this pollutant finding a home on the snow plains of the Arctic.  Snow normally reflects sunlight efficiently to provide negative feedback countering the effects of global warming.  This is one of the Arctic’s sole defenses left to stop severe melting as temperatures rise.  But as black carbon accumulates in the Arctic and replaces snow-white with carbon-black, reflective surfaces transform into light-absorbing hothouses, amplifying warming trends and pushing the Arctic closer to its watery fate.

If black carbon normally arises from human combustive processes, how does it end up blackening the Arctic?  This is the question researchers are still trying to answer.  Computer climate models are one of the best tools to understand climatic processes.  Unfortunately, all of them underestimate black carbon levels in the Arctic compared to on-the-ground, experimental measurements.

Researchers expect two possibilities could account for the experiment-model discrepancy: 1) there are unknown sources of black carbon in the Arctic that we haven’t found and thus haven’t included in current climate models; or 2) the models aren’t accurately capturing how black carbon moves along atmospheric currents from mid-latitudes to the pole.  There is some evidence to support the latter.  Low-pressure systems begin at mid-latitudes and follow the polar front to the Arctic.  This provides a potential pathway for black carbon to arise in industrial centers in the Northern Hemisphere (U.S., Europe, China) and surf all the way to the top of the planet.  But global climate models have predicted that the polar front drops all the black carbon through precipitation far before the Arctic Circle.

A finer look

Any computational climate model must divide the planet into a grid of finite-size regions, defining the resolution of the model.  The size of these grid regions effectively sets a limit to what can be seen: models are blind to any behavior changing on length scales smaller than the grid size.  Previous models have used a resolution of 50 kilometers, but it is well known that a weather system like the polar front contains small vortices and quick temperature changes on a scale much smaller than this.  Knowing this, Sato et al. improved their model resolution by an order of magnitude, decreasing each grid region to a width of 3.5 kilometers. Results using this model provide the first answers to how so much black carbon could accumulate in the Arctic.

The figure below shows results from the same simulation done at three levels of resolution – 3.5 km, 14 km, and 56 km (top, middle, and bottom rows, respectively).  Comparing the simulations illuminates two major features driving black carbon transport to the Arctic that previous models could not capture: 1) small-scale vortices and 2) cloud formation.

model

The impact of vortices can be seen in the left part of the figure.  The gray-scale images on the left visualize the polar front by mapping liquid water mass across a region near the southern tip of the Arctic.  This type of graphic essentially describes the direction of wind currents in the front. The 56-km model only has sufficient resolution to describe a broad, candy-cane-like structure at the center of the weather system.  In contrast, the 3.5-km resolution model predicts smaller-scale vortices within the larger, curling system.  The researchers predict that these vortices impact how much black carbon can be transported over long distances, however this idea must be explored further in future work.

Second, and more importantly, the 3.5-km resolution model improved the description of cloud formation.  The 56-km model smeared cloud formation across most of the front, thus predicting more rain that would move black carbon out of the atmosphere and onto the ground before reaching the Arctic.  In contrast, the 3.5-km model predicted much sparser cloud formation and less precipitation, allowing more black carbon to reach the pole before being released by the clouds.

As a result of these two factors, the finer-resolution model predicts much more black carbon at latitudes near 60 degrees N.  This can be seen in the righthand side of the figure, in which green regions indicate much more black carbon than blue ones.  We now have an answer: industrial operations in the Northern Hemisphere, burning coal, oil, and biomass, are likely channeling black carbon to the Arctic via the polar front.

Not done yet

Despite this incredible step forward in understanding, the finer resolution model still underestimates experimental black carbon levels in the Arctic.  The authors admit that, even at this fine of a resolution, the model is probably missing even more detailed features controlling cloud formation and precipitation.  The only answer is better supercomputing power to support models with sub-kilometer resolution.

But this is science – every new answer provides a glimpse of how a little bit better technology could give us even more comprehensive understanding.  The trend – that we are closing the gap between experimental and modeled results – is the important and hopeful part.  Once we understand how black carbon arrives at the Arctic, we can finally begin the hard work of trying to stop the process.

 

References

[1] Sato  Y et al. “Unrealistically pristine air in the Arctic produced by current global scale models.” Scientific Reports6:26561, 2016.

Figures

Figure of model results courtesy of Reference 1

 

 

Sato, Y., Miura, H., Yashiro, H., Goto, D., Takemura, T., Tomita, H., & Nakajima, T. (2016). Unrealistically pristine air in the Arctic produced by current global scale models Scientific Reports, 6 DOI: 10.1038/srep26561

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The great Amazon experiment, or, how beer-makers can help understand the rainforest and climate change

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If you happen to brew beer in Brazil, consider selling a tank or two of carbon dioxide (CO2) to researchers building tall towers in the Amazon rainforest.  Your business could help the scientific community understand the fate of the forest and predict just how much greenhouse gas will accumulate in the atmosphere by the end of the century.

As discussed in Science [1], a multidisciplinary initiative is underway in the central Amazon to understand how increased anthropogenic CO2 in the atmosphere will affect the spread or decline of the world’s largest rainforest.   The potential knowledge gained from this research could inform more accurate climate models and tell us whether the Amazon is fated for devastation before it is too late to do something about it.

The tropical response

How will tropical forests respond to global warming?  This simple question is maddeningly difficult for scientists to answer but incredibly important to understand planetary climate change.  Terrestrial vegetation absorbs about 30% of all anthropogenic CO2 and rainforests worldwide account for about 2/3 of this sequestration.   Since the Amazon accounts for over half of the world’s entire rainforest area, understanding the relationship between tropical forests and climate change begins with the 5.5 million square kilometers of lush forests and rich biodiversity in South America.

Unfortunately, little data exists to understand this complex CO2-forest relationship.  On the one hand, increased atmospheric CO2 leads to higher temperatures, which models predict could create severe droughts that destroy much of the rainforest [2].  However, it is well known that increased CO2 also encourages plants to absorb more of the greenhouse gas and induces even more photosynthesis, known as the fertilization effect.  This process leads to more plant biomass and can expand the extent of the forest.  When the same models predicting drought and devastation are modified to account for increased fertilization, the Amazon suddenly demonstrates a robustness against global warming [3].

Simulating the future

So which effect – hot droughts or thriving biomass – wins out?  Researchers hope to collect the first evidence to answer this question over the next year using a ring of 35-meter towers spewing CO2 into a patch of rainforest just north of Manaus.  The towers, known as a ‘Gas Ring’, encompass a circular area 30 meters in diameter and release enough CO2 to increase the regional atmospheric concentration to about 600 parts per million (ppm), 200 ppm more than current levels.  The idea is to simulate atmospheric conditions that could occur by the end of the century due to anthropogenic emissions and then study how the rainforest reacts.

This type of experiment, known as free-air CO2 enrichment (FACE), has already been performed in numerous temperate forests to the north in the 1990’s.  These studies demonstrated that increased CO2 does spur photosynthesis and increases plant biomass, as theory predicts, allowing more CO2 to be sucked out of the atmosphere [4].  This is an early sign that temperate forests could buffer the planet against climate change, providing a negative feedback loop that slows the accumulation of CO2 in the atmosphere.

Some signs already suggest that the Amazon rainforest could be an even stronger buffer.  The higher temperature in the tropics would work constructively with increased CO2 to increase photosynthetic rates.  However, other factors, like the amount of phosphorus in rainforest soil, could be a limiting factor that determines just how much more biomass can be supported.  Higher growth rates in the Amazon have already been observed but scientists have yet to find the causal link [4].

The FACE experiment could change that.  This is “one of the most exciting experiments on the planet,” says David Lapola, lead scientist from Sao Paulo State University in Brazil [1].  Beginning with a summit of scientists in Washington D.C. in 2013, the first tower ring is now being constructed.  Researchers will measure a swath of variables like changes in tree trunk size, debris buildup, soil respiration, and root growth.  Forest responses will be studied over two years and compared to a control region before expanding to four treated plots and four control areas.

The necessity to study multiple plots represents just one of many challenges for this unprecedented experiment.  The unmatched biodiversity in rainforests means that results from one relatively small sample cannot be generalized to the forest as a whole.  Also, the engineering challenge of building large enough towers to encompass the tallest trees of the Amazon has caused multiple delays and false starts.  And then there is the CO2 problem.  Annual shipment of the gas to supply the towers costs several million dollars.  Researchers are now looking at business agreements with local soft drink and beer companies to provide the gas.   There is also the question of whether to build pipelines to transport the gas or build roads for trucks.

Improving predictions

Despite these challenges and delays, construction of the first Gas Ring should begin within the year and results will come in six months after its completion.  With hard evidence finally available, climate models will hopefully provide estimates of future CO2 concentrations with less variability than current models.  By 2100, models predict atmospheric CO2 concentrations between 699 to 1130 ppm, an enormous variation largely due to a lack of knowledge about fertilization.  This range in predicted concentration corresponds to a 2.4 C global temperature range, the difference between drowned or surviving coastal cities, drought-ridden or thriving crops.

No data better emphasizes the importance of understanding the Amazon to gain insight to the planet’s future.  Several rings of towers, a modern-day Stonehenge erected to push the limits of science and engineering, are one of our only bets to begin providing answers.

References

[1] Grossman, D. “Amazon rainforest to get a growth check.” Science, 352, 635-636, 2016.

[2] Cox, P.M. et al. “Acceleration of global warming due to carbon-cycle feedback in a coupled climate model.” Nature408, 184-187, 2000.

[3] Cox, P.M. et al. “Sensitivity of tropical carbon to climate change constrained by carbon dioxide variability.” Nature494, 341-344, 2013.

[4] Tollefson, J. “Experiment aims to steep rainforest in carbon.” Nature496, 405-406, April 25 2013.

Photo Credits

Photo of tower rings from FACE experiment in temperate forests courtesy of David Lapola

Grossman, D. (2016). Amazon rainforest to get a growth check Science, 352 (6286), 635-636 DOI: 10.1126/science.352.6286.635

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Simple ideas for going green now

I’m happy to present a guest post today by Sam from Organic Lesson, his personal blog covering organic gardening and ways to live harmoniously with the planet. As a follow-up to Earth Day, he’s created a beautiful infographic outlining some simple ways that people can ‘go green’ and reduce their environmental footprint. Thanks Sam! For more tips and discussions about green living, please visit his blog.

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According to data released from NASA, February 2016 was the hottest February ever recorded in the history of modern temperature records. We are also using up natural resources much faster than what would be considered sustainable.

In the following infographic by Organic Lesson, you can learn more about the concerning environmental impacts that human beings have had on natural resources like water as well as the steps you could personally take to go green. Many people are daunted by the idea of going greenbecause it sounds like a lot of heavy lifting is needed to truly make a difference. But that isn’t the case. The action of going green could be as simple as remembering to switch the room lights off or to take shorter showers. With Earth day just behind us, there is no better time than to start now.

For 60 other simple tips to reduce your impact, from checking your tire pressure to starting a green commitee, check out Organic Lesson’s full list here.

earth-go-green-infographic

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A very beautiful and unusual animal in danger

Amazing_Great_Barrier_Reef_1

“We are tied to the ocean.  And when we go back to the sea, whether it is to sail or to watch – we are going back from whence we came.” — John F. Kennedy

Coral reefs across the world could vanish within this century.  This is a warning from scientists, not attention-seeking alarmists.  This is a warning from men and women who spend their lives diving along the 2300-km Great Barrier Reef, who know the reef-supported marine communities like beekeepers might know their hives.  In the words of Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland, “this is not in the future, it’s happening right now.”

On a day when we celebrate Earth’s suppleness, its diversity, its numerous gifts wrapped in blue and green, as one of its stewards we must also face the threats to its stability that were created by us and can only be solved by us.  Like the poor canary forced into the coal mine, coral reefs sound the alarm about fundamental changes to the ocean already caused by anthropogenic global warming.  Unlike the doomed canary, new discoveries also show that reefs embody the natural resilience of so much life on the planet, a lasting signal of hope that the biodiversity and ecosystems on which our society depends can be saved if we take action to mitigate climate change.

Worldwide bleaching

“A very beautiful and unusual animal,” theoretical physicist, Anthony Garrett Lisi, mused. “Each coral head consists of thousands of individual polyps.  These polyps are continually budding and branching into genetically identical neighbors.”  As these organisms expand over thousands of square kilometers, they provide habitat for over one million marine species and serve as natural breakwaters to minimize the impact from storms and hurricanes.  The fish, crab, lobsters and other life attracted to this natural shelter sustain fishing economies, providing financial livelihood for an estimated 500 million people.  If you want to put a dollar amount on it, try about 100,000-600,000 US dollars of annual economic value per square kilometer of coral [1].

The bright colors of coral that attract tourists from around the world do not serve aesthetic purposes alone.  Small algae known as dinoflagellates attach to the coral, absorbing sunlight and providing energy and nutrients through photosynthesis for both itself and its host.  This symbiotic relationship leads to the bright colors but also sustains the coral and its ability to support such a diverse and expansive ecosystem.  No more algae means no more coral.  Such is the reality of ecosystems and a lesson we must rapidly learn: organisms do not survive in isolation.

Unfortunately, warming ocean temperatures drive algae off the coral, an effect known as bleaching that kills the nutrient-deprived coral if it lasts long enough.  Such events are most severe during El Nino events when eastern Pacific waters warm, easterly trade winds weaken, and sea surface temperatures generally rise.  The worst of such events hit in 1998, when 16% of all coral reefs died off from sustained bleaching.  Another occurred in 2002, when 18% of all reefs in the Great Barrier Reef in Australia were badly bleached.

That was the past.  Travel forward in time fifteen years to 2016, having just survived the hottest year on record due to a strong El Nino that piled on top of an average increase in sea surface temperature from global warming.  The fate of coral reefs from Australia to the Caribbean looks dire.

“Only four reefs out of 502 [observed] had no bleaching,” says Terry Hughes, who directs the Australian Research Council Center of Excellence for Coral Reef Studies [1].  She has joined other marine authorities in diving through and flying over the entire extent of the Great Barrier Reef off the coast of Australia.  In both cases, scientists use a 0-5 scoring system to quantify the health of coral systems, where 0 indicates no bleaching, 3 is 30-60% bleaching, and 4 is more than 60% bleached.  Today, more than 95% of the documented Great Barrier Reef has a score of 3-4.  Remember that other bad bleaching year in 2002?  Only 18% of reefs scored 3-4 then.  This is a bleaching epidemic on a whole other level.

The Great Barrier Reef is a great location to start understanding coral health because it benefits from the largest scientific and conservation investment compared to other reefs.  Because of this, even more remote parts of the ecosystem have been explored, far from fishing, pollution, and tourism.  Even these areas show significant bleaching, an early indication that it is not direct human contact but rather the general rise in sea surface temperatures that is forcing algae to jump off their coral hosts.

El Nino isn’t done, either.  Although its most intense effects may be in decline, scientists expect its weather patterns to last another year.  Because of this, bleaching has expanded around the globe, seen in Hawaii late last year, the British Indian Ocean Territory between Africa and Indonesia, near Fiji, and expected in the Caribbean this summer.

Relying on resilience

Despite the massive scale of bleaching over the past couple years, there are signs of coral resilience against increasing temperatures that scientists are beginning to understand.  Given the same rise in sea temperature, some corals bleach and die off quickly whereas others are able to retain their algae for longer periods of time.  What allows some coral reefs to survive this temperature shock?

The answer lies in the coral’s history.  Using satellite records of sea surface temperature over the past three decades, scientists have connected past changes in temperature with bleaching events and survival [2].  They found that certain coral reefs had survived through small temperature changes still below the threshold for bleaching.  This ‘protective’ trajectory changed the physiology of the symbiotic algae and effectively prepared the coral-algae system to survive more severe temperature shocks.  Thus, when large increases in temperature occur during El Nino years that surpass the bleaching threshold, these prepared subgroups of coral are more resilient and survive to a greater degree compared to coral that did not have the chance to adapt through physiological changes.  Just like people might respond better to a crisis if they’ve had practice dealing with less severe problems in the past, the coral and algae need exposure to slight temperature fluctuations to adapt and prepare their physiology for their own form of crisis.

These findings provide hope for coral survival and suggest that conservation efforts could focus on those parts of the coral reefs without this resilience.  However, global warming completely changes the picture.  Whereas only El Nino could push many coral reefs above the bleaching threshold in the past, warming sea surface temperatures will increase the likelihood that even small temperature fluctuations will push coral beyond the bleaching threshold without exposing them to low-stress temperature events to learn how to adapt.

Based on scientific models and assuming that the ocean warms by 2 degrees C by 2100 (as expected by most models), the percent of corals given opportunities to adapt will fall from 75% to 20% and bleaching events without preparation will rise from 20% to 70%.  In effect, climate change destroys any chance for coral to gain resilience against ocean warming.

Enter the dire predictions that coral reefs will not survive this century.

A new hope

So scientists are learning just how corals respond to hotter oceans.  Reefs can be resilient if given the chance, but global warming is limiting this opportunity.  Any tricks up their budding branches?

Maybe.  A research expedition at the mouth of the Amazon River has serendipitously discovered an entirely new coral reef, spanning 1000 kilometers in the unlikeliest of locations [3].  Brazilian and American researchers were originally trying to understand how the Amazonian plume – the great rush of freshwater pouring into the ocean from the river – affects carbon dioxide absorption into the ocean.  However, one Brazilian had another objective in mind.

A paper from almost three decades had documented fish in the area that are normally associated with a coral reef.  The Brazilian researcher, Rodrigo Moura, knew of the finding and had always wanted to start a search.

“I kind of chuckled when Rodrigo first approached me about looking for reefs.  I mean, it’s kind of dark, it’s muddy – it’s the Amazon River,” said Patricia Yager, an American researcher from the University of Georgia.

But they looked anyway.  Yager shipped a dredge across two continents to their boat and sent it down to the ocean floor.  After it returned to the surface, its scoop was filled with corals, fish, and sponges.  A new reef had been found.

None of the researchers could believe the discovery at first because they thought the Amazonian plume would stir up too much dirt, letting too little sunlight penetrate to the seabed to support photosynthesis and coral health.  Most well-known coral reefs are in shallow waters with easy access to sunlight.

The newly found Amazonian reef reveals just how robust and unexpected coral reefs can be.  This one survives on little sunlight but still supports many marine species.  Its existence gives hope that reefs can survive harsher conditions, possibly hotter and more acidic ones that will inevitably arise as global warming continues its inexorable pace.

Taking the slim chance that coral reefs can survive any environmental change we throw at them seems risky.  Instead, we must do all we can to reduce carbon emissions, slow warming, and maintain a climate that both we and coral can survive.  Because, when we say ‘Happy Earth Day’, what we really mean is ‘Happy Earth-as-we-know-it Day’, or ‘Happy Earth-that-supports-our-society Day’, a greeting we may not be able to use in the years to come unless global cooperative action is taken to reduce greenhouse gas emissions.

References

[1] Normile, D. “El Nino’s warmth devastating reefs worldwide.” Science352(6281), 15-16, April 8 2016.

[2] Ainsworth, TD et al. “Climate change disables coral bleaching protection on the Great Barrier Reef.” Science, 352(6283), 338-340, April 15 2016.

[3] Meyer, R. “Scientists have discovered a 600-mile coral reef.” The Atlantic, accessed April 21, 2016.

Photo Credits

Photo of Great Barrier Reef courtesy of Sarah Ackerman via Wikipedia

 

Ainsworth, T., Heron, S., Ortiz, J., Mumby, P., Grech, A., Ogawa, D., Eakin, C., & Leggat, W. (2016). Climate change disables coral bleaching protection on the Great Barrier Reef Science, 352 (6283), 338-342 DOI: 10.1126/science.aac7125

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