All Dried Up? Modeling the Effects of Climate Change in California’s River Basins

Mono Lake
Whether you are trapped inside because of it, or mourning the lack of it, water is on everyone’s mind right now. Too much snow in the Midwest and Northeast has been ruining travel plans, while too little snow is limiting Californians’ annual ski trips. No one wants to drive three hours only to find a rocky hillside where their favorite slope used to be.

It’s hard to deny that abnormal things are happening with the weather right now. Recently, Governor Jerry Brown officially declared a state of emergency in California due to the drought and suggested that citizens cut water usage by 20%. With no relief in sight, it is important not only to regulate our current water use, but also to reevaluate our local programs and policies that will affect water usage in the future. So, how do we go about making these decisions without being able to predict what’s next? A recently published PLOS ONE article may offer an answer in the form of a model that allows us to estimate how potential future climate scenarios could affect our water supply.


Researchers from UC Berkeley and the Stockholm Environmental Institute’s (SEI) office in Davis, CA built a hydrology simulation model of the Tuolumne and Merced River basins, both located in California’s Central Valley (pictured above). Their focus was on modeling the sensitivity of California’s water supply to possible increases in temperature. When building the model, the authors chose to incorporate historical water data, current water use regulations, and geographical information to estimate seasonal water availability across the Central Valley and the San Francisco Bay Area. They then ran various water availability scenarios through the model to predict how the region could be affected by rising temperatures.

Using estimated temperature increases of 2°C, 4°C, and 6°C, the model predicted earlier snowmelts, leading to a peak water flow earlier in the year than in previous years. The model also forecasted a decreased river flow due to increased evapotranspiration (temperature, humidity, and wind speed). The water supply was also estimated to drop incrementally with each temperature increase, though it is somewhat cushioned by the availability of water stored in California’s reservoirs.


The authors used an existing model as an initial structure, and built upon it to include information on local land surface characteristics, evapotranspiration, precipitation, and runoff potential. Surrounding water districts were modeled as nodes and assigned a priority according to California’s established infrastructure and legislation. Using this information, the authors state that the tool is equipped to estimate monthly water allocation to agricultural and urban areas and compare it to historical averages for the same areas.

Though a broad model, the authors present it as a case study that provides estimates of longer-term water availability for the Central Valley and Bay Area, and encourage other areas to modify its design to meet the needs of their unique locales. Those of us looking for more specific predictions can also use the tool to create models with additional information and refined approximations, allowing flexibility for future changes in land use and policy. For now, we might have a good long-term view of our changing water supply and a vital tool as we race to keep up with our ever-changing world.

Citation: Kiparsky M, Joyce B, Purkey D, Young C (2014) Potential Impacts of Climate Warming on Water Supply Reliability in the Tuolumne and Merced River Basins, California. PLoS ONE 9(1): e84946. doi:10.1371/journal.pone.0084946

Image 1 Credit: Mono Lake by Stuart Rankin

Image 2 Credit: Figure 1 pone.0084946

Image 3 Credit: Figure 2 pone.0084946

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Crisis in the Late Bronze Age Triggered by Environmental Change


What does it take to topple a civilization, or a whole group of them? Over three thousand years ago, agriculture and trade-based societies flourished in the Eastern Mediterranean. Yet something fishy happened circa 1200 BC that brought these cultural and commercial centers to their knees—something that has left historians in the dark.

Correspondence from that time attributes the decline, at least partially, to invasions from a band of raiders, referred to as Sea Peoples. Other scholars studying this period point to natural disasters, such as earthquakes or drought. Research recently published in PLOS ONE reveals a more insidious culprit: Climate change may have fueled drought, the invasions, and eventually the collapse of these civilizations in what historians call the Late Bronze Age crisis.

To explore the environmental factors behind this crisis, the researchers took continuous core samples from modern-day Cyprus, at what is now called Larnaca Salt Lake, or Hala Sultan Tekke.


Core samples were analyzed for their pollen content and tested for the presence of dinoflagellates (pictured), a type of marine plankton. The researchers then studied the abundance and variety of plants represented by the ancient pollen and plotted fluctuations in the proportions of both between 1500 BC and 1500 AD. With similar data from nearby Syria, they reconstructed likely climate conditions in the region during the Late Bronze Age.

They found the abundance of marine plankton decreased around 1200 BC, suggesting the region was gradually becoming drier, as the lake lost its connection to the sea.  The pollen record reveals a shift towards plants that could handle drier weather, indicating a decrease in rainfall. Dwindling rain, the researchers suggest, may have made it difficult to maintain agricultural production and led to food shortages. These shortages might also have caused people to travel, migrate, or raid in search of more food.  This drought lasted three hundred years and coincides with the Sea People invasions.

It takes a lot to topple civilizations, and climate change has played its part in ending those in the Eastern Mediterranean during the Late Bronze Age. This evidence adds to the growing body of literature documenting the effects of climate change. This latest research adds a compelling chapter to the story of climate change, from which everyone can learn.


Citation: Kaniewski D, Van Campo E, Guiot J, Le Burel S, Otto T, et al. (2013) Environmental Roots of the Late Bronze Age Crisis. PLoS ONE 8(8): e71004. doi:10.1371/journal.pone.0071004


Keuninck (Coninck) Kerstiaen de – Fire of Troy, from Wikimedia

DINOFLAGELLATE, by fickleandfreckled

Heating up the Science Behind PLOS’ New Climate Change Collection

Satellite images of penguin colonies in the southern Ross Sea

From penguin colonies in Antarctica, to California birds and North Carolina bugs, this month PLOS ONE focuses on the far-reaching aspects of climate change. In conjunction with the annual meeting of the Ecological Society of America (ESA), PLOS ONE and PLOS Biology unrolled a new collection of 16 research articles, curated by PLOS ONE Academic Editor, Ben Bond-Lamberty. The collection, “Ecological Impact of Climate Change”, features many articles that made a splash in the media. Here are some of the highlights:

Spring flowers are blooming earlier now than they did in the past. In a recent study, researchers compared the average flowering time for native species in Massachusetts and Wisconsin to data recorded by notable American naturalists Henry David Thoreau and Aldo Leopold. These native species have shown remarkable flowering shifts, especially during recent years: In 1865, Thoreau observed the highbush blueberry flowering in mid-May; in 2012, researchers observed this species flowering six weeks earlier in early April. For more about this study, visit National Geographic, NPR, and MSNBC.

Like spring flowers, corals also react to increasing temperatures, but to a much more ghostly effect. When pressured by unusually warm or polluted waters, corals shed the algae that enliven them with color, becoming white.

Tioman Island, Malaysia, Acropora colony

New research suggests that this phenomenon, known as coral bleaching and often fatal for coral colonies, may not be as devastating as expected: Coral colonies that survived previous coral bleaching were much more likely to rebound successfully the next time it occurred. An astounding 95% of Acropora, a coral species highly susceptible to bleaching, survived at a research site in Singapore in 2010. Read more about these tough coral taxa, in the New York Times blog.

Summer days are heating up in the city, too, and urban, tree-dwelling insects are thriving as a result. A recent PLOS ONE article reports that scale insects like Parthenolecanium quercifex are 13 times more numerous in the hottest parts of Raleigh, North Carolina, than in cooler, neighboring rural areas.

Scale Bugs CCBY Aug blog

And these scaly squatters don’t stop once they settle down. Researchers also found that urban scale insects were four times more abundant when placed in hot greenhouse conditions than rural scale insects in the same conditions. The Atlantic Cities and Discovery News have more on this and other urban insects studies.

As temperatures continue to rise, researchers in this PLOS ONE study integrated climate change threats with traditional conservation concerns by comparing the vulnerability of California’s birds in relation to the predicted effects of climate change over the coming years. Of the 29 threatened-bird taxa considered in the state of California, these researchers determined 21 of those 29 (72%) are considered vulnerable to climate change. Lucky for us and the birds who call those most vulnerable coastal environments home, the findings of this study can be used as an assessment tool to foster future conservation efforts. For more local and international coverage, check out KQED News and the Huffington Post.

Read Ben Bond-Lamberty’s overview of the Collection, learn how climate change may impact coffee plants, or more from the PLOS Blogs network. View the entire Collection here. For more news on PLOS ONE papers headlining in August, dive into our Media Tracking Project.


Ellwood ER, Temple SA, Primack RB, Bradley NL, Davis CC (2013) Record-Breaking Early Flowering in the Eastern United States. PLoS ONE 8(1): e53788. doi:10.1371/journal.pone.0053788

Guest JR, Baird AH, Maynard JA, Muttaqin E, Edwards AJ, et al. (2012) Contrasting Patterns of Coral Bleaching Susceptibility in 2010 Suggest an Adaptive Response to Thermal Stress. PLoS ONE 7(3): e33353. doi:10.1371/journal.pone.0033353

Meineke EK, Dunn RR, Sexton JO, Frank SD (2013) Urban Warming Drives Insect Pest Abundance on Street Trees. PLoS ONE 8(3): e59687. doi:10.1371/journal.pone.0059687

Gardali T, Seavy NE, DiGaudio RT, Comrack LA (2012) A Climate Change Vulnerability Assessment of California’s At-Risk Birds. PLoS ONE 7(3): e29507. doi:10.1371/journal.pone.0029507

Image 1: Satellite images of penguin colonies in the southern Ross Sea. doi:10.1371/journal.pone.0060568

Image 2: Tioman Island, Malaysia, Acropora colony. doi:10.1371/journal.pone.0033353

Image 3: Ants and sapsuckers by John Tann


Coffee Plants Don’t Like It Hot

Guest blogger Atreyee Bhattacharya is a science correspondent and climate scientist, currently a research affiliate at the Department of Earth and Planetary Sciences, Harvard University. 

espressoLike most, I like my coffee black and piping hot. Coffee plants, however, may not be as fond of the heat.

When thinking about the impact of changing climate (increased droughts, wilder fluctuations in seasons) and increasing pest activity on food production—my thoughts tend toward crops such as rice, wheat, and corn. Not so much wine, chocolate, or coffee, though I probably consume more coffee throughout the day than I do these other staples.

However, two recent papers published in PLOS ONE deliver a double whammy to coffee, or more particularly the Coffea arabica plant, a species that today accounts for more than 70 percent of the world’s coffee. (Another, less common, variety is C. robusta, which has twice the caffeine content.)

In a 2011 study, Juiliana Jaramilo from the University of Hannover and her coauthors, Figure 2showed that warming air and land temperatures can change the distribution of the coffee berry borer Hypothenemus hampei in East African C. arabica producing regions.

The borer, a pest that attacks coffee beans, “causes losses exceeding US $500 million annually, and worldwide affects many of the more than 25 million rural households involved in coffee production” the study reports. A serious infestation can lower coffee production by more than three times!

Until about ten years ago, reports of H. hampei attacks on coffee plants growing above 1500 m (the preferred altitude of cultivated and naturally occurring C. arabica) were few and far between. But thanks to the 0.2-0.5 degrees Celsius temperature increase in coffee growing regions of East Africa, the pests are now found at higher altitude plantations as well.

As temperatures continue to rise as per projections from the  Intergovernmental Panel on Climate Change (IPCC), coffee borer infestations in this region are likely to spread  farther. Increasing temperatures will increase the number of H.hampei generations each year from 1-4.5 to 5-10 or more.

“These outcomes will have serious implications for C. arabica production and livelihoods in East Africa,” caution the authors, adding, “We suggest that the best way to adapt to a rise of temperatures in coffee plantations could be via the introduction of shade trees in sun grown plantations.”

Figure 3Though C. arabica plants do like to grow in the shade; another study indicates that this protection may still not be enough to combat the threat of warming temperatures. According to this research by Aaron Davis from the Royal Botanic Gardens in the United Kingdom, warming temperatures may make several localities within southwest Ethiopia and neighboring regions climatologically ill-suited to growing C. arabica.

“Based on known occurrences and ecological tolerances of Arabica, bioclimatic unsuitability would place populations in peril, leading to severe stress and a high risk of extinction,” write the researchers.

According to their estimates, the most favorable outcome of warming is a 65% decrease in areas with climate suitable for coffee plantations, and at worst, an almost 100% loss of these regions by 2080. In terms of available area for growing coffee, the most favorable outcome  is a 38% reduction in suitable space, and at worst a 90% reduction. Neighboring areas could fare even worse by as early as 2020.

Coffee is a 90-billion-dollar industry , but it is an industry that depends on long-term planning. The beans that we grind every morning today were planted about 7-10 years ago, and our morning brew a decade hence depends on today’s plantations.

Demand for coffee continues to rise in our ‘coffee culture’, and C. arabica still constitutes about 75-80% of the world’s coffee production. C. arabica is believed to be the first species of coffee to be cultivated, well over a thousand years ago. It epitomizes an incredible journey, and is one beverage that is certainly worth a second thought as rising temperatures threaten its existence.

Read these studies and more on the ecological impacts of climate change in the new PLOS Collection:

Citations:Jaramillo J, Muchugu E, Vega FE, Davis A, Borgemeister C, et al. (2011) Some Like It Hot: The Influence and Implications of Climate Change on Coffee Berry Borer (Hypothenemus hampei) and Coffee Production in East Africa. PLoS ONE 6(9): e24528. doi:10.1371/journal.pone.0024528

Davis AP, Gole TW, Baena S, Moat J (2012) The Impact of Climate Change on Indigenous Arabica Coffee (Coffea arabica): Predicting Future Trends and Identifying Priorities. PLoS ONE 7(11): e47981. doi:10.1371/journal.pone.0047981


Espresso by Richard Masoner on Flickr 

Distribution of the coffee berry borer (Hypothenemus hampei) in Eastern Africa under current climate. The EI values (0–100), indicates unsuitability of the location’s climate (0), and a ‘perfect’ climate for the given species (100). doi:10.1371/journal.pone.0024528.g001

Predicted and actual distribution of indigenous Arabica. Green dots show recorded data-points. Colored areas (yellow to red) show predicted distribution based on modeling. A context map is given in the top left hand corner. doi:10.1371/journal.pone.0047981.g001

Announcing the Ecological Impacts of Climate Change Collection

Ecoclimate change collection

Post authored by Collection Curator Ben Bond-Lamberty 

The ecological impacts of climate change are broad and diverse, and include alterations to species’ range limits, plant phenology and growth, carbon and nutrient cycling, as well as biodiversity and extinction risk. Recent PLOS articles have used a variety of experimental and observational approaches to examine these subjects.

Identifying at-risk regions, taxa, and species is a critical first step in adaptation and conservation efforts. A study by Mouillot et al. suggested that rare species are particularly important in conservation efforts, as rare species in diverse ecosystems are not replaceable by other species that fulfill the same ecological functions. At the same time, both rare and more common species experience the ecological impacts of climate change. Foden et al. combined biology and ecology to assess, on a global scale, the climate change vulnerability of birds, amphibians, and corals based on expert assessment and literature surveys. In a more regionally focused study, Gardali et al. assessed climate-change risk for California’s vulnerable bird species.

Birds were also the focus of two studies documenting how particular species can be ‘winners’ or ‘losers’ in a changing climate. Receding glaciers and thus increased breeding habitat have led to population increases for Adélie penguins in the southern Ross Sea. The outlook was more mixed for Pacific western grebes , which have shifted south, perhaps in response to changes in their forage fish prey. Further down the food chain, Suikkanen et al.  used thirty years of marine data to infer that climate change and eutrophication drove a trophic shift in Baltic Sea food webs.

Long-term data were also used to study how flowering dates have changed since the mid-19th century. In a study that received extensive media coverage, Ellwood et al. used flowering records initiated as early as 1852 to show that high spring temperatures in 2010 and 2012 resulted in the earliest flowering in recorded history in the eastern United States. The biological pathways through which temperature affects seasonal timing in endotherms were discussed by Caro et al. Two other widely-covered studies focused on coffee: predicting future trends and identifying priorities, and climate change impacts on this plant and one of its important pests. Both examine adaptation possibilities for managing coffee crops over the coming century.

Adaptation and vulnerability were central themes for Guest et al., who reported that corals under thermal stress showed lower bleaching susceptibility at locations that bleached a decade earlier, implying an adaptive or acclimatization response. The molecular mechanisms behind such thermal tolerance were explored by Bellantuono et al.

Finally, the ecological impacts of climate change affect our health, the urban environment, and the agricultural economy. Airborne pollen counts have been increasing across Europe, and Ziello et al. suggest that rising CO2 levels may be influencing this increase. In another study, Meineke et al. used an elegant combination of observation and manipulative experiments to show that urban warming was a key driver of insect pest outbreaks in the southeastern U.S. Rising temperatures are a significant driver for the expanding range of Asian tiger mosquitoes, known vectors for West Nile and other viral infections. Warming was also found to contribute to the decreasing quality of grassland for grazers such as bison and cattle, although the effects are often exerted via complex interactions with other factors.

The broad range of these papers emphasize not only the multi-faceted impacts of climate change on ecological and human systems, but also the breadth and depth of research on these subject being reported in the PLOS journals. These journals seem a particularly appropriate venue for the ‘citizen science’ and other long-term data used by many of these studies.

Collection Citation: Ecological Impacts of Climate Change Collection (2013)

Image Credit: (Clockwise from top) William Warby. Thomas Vignaud. PLOS Biology. 2011. 9(4). Colombi et al. PLOS ONE. 2013. Soto-Azat et al. PLOS ONE. 2013.

This Collection is also available on Flipboard, please search “PLOS Collections” to subscribe.


Ecology Highlight: PLOS ONE at ESA 2013


climate change vulnerable species


PLOS ONE is eagerly anticipating a trip to the 98th annual meeting of Ecological Society of America, August 4 – 10 in Minneapolis, to meet with our Academic Editors, authors, reviewers, and readers and to learn about the latest in ecology research. Attending the meeting will be Terry Monahan (Senior Editorial Manager), Lindsay Morton (Publications Manager), Elizabeth Silva (Associate Editor), and myself (Meg Byrne, Associate Editor).

In conjunction with the Ecology Society of America meeting, PLOS will be launching “The Ecological Impact of Climate Change Collection” on Monday, August 5, 2013. This collection, curated by PLOS ONE Academic Editor Ben Bond-Lamberty, highlights 16 articles recently published in PLOS ONE and PLOS Biology. These articles underscore the far-reaching impacts of climate change and the important contributions scientists are making to increase our understanding of how diverse species are effected by and are responding to climate change. Come back to the EveryONE blog on Monday for a full introduction to the collection by Dr. Bond-Lamberty.

“The Ecological Impact of Climate Change Collection” is part of a larger research and blog series at PLOS helping to refocus the conversation on climate change. The series is scheduled to run over a two-week period, between July 29 and August 9, and features pieces by 10 regular and guest bloggers, including award-winning science journalist Linda Marsa. Topics include changing habitats and species, climate modeling, the impact of climate change on disease, the difficulties facing science writers covering climate change, and the politics of climate change science.

Come find us at the meeting: We would love to hear about your research and your thoughts about the future of science publishing. We’ll be at booth #501 from Monday, August 5, 2013 through Thursday, August 8, 2013.

PLOS ONE Academic Editors: We hope you can join us for our Editorial Board Reception on Wednesday, August 8, from 6 to 9 PM.  We look forward to chatting with you in person, filling you in on our future plans, getting your feedback, and saying a huge “Thank you!” Please contact Lindsay Morton for further information.

Authors: Come get a special author t-shirt! Also, let us show you how to track your article-level metrics, including the number of HTML views, PDF downloads, citations, comments, bookmarks, and even tweets and Facebook likes. We can also demonstrate one of our latest features, Relative Metrics (Beta), which allows you to compare your paper’s usage to the average usage of articles in related subject areas.

Consider submitting your manuscript to PLOS! We will be available to answer your questions about submitting to PLOS ONE and PLOS Biology. Come learn about the many advantages of publishing in our open access journals, including free readership rights, reuse and remixing rights, unrestricted copyright, automatic posting of the article, and machine accessibility of the published article.

Call for New Academic Editors: Because of a growing number of submissions in ecology, PLOS ONE is looking to grow our board in this area. If you run your own research lab, supervise students and postdocs, hold research grants, and have a strong publication record, we hope you will consider applying to join our Editorial Board. Please stop by the booth for more information or contact Lindsay Morton.

We look forward to visiting the Twin Cities, briefly escaping the summer fog in San Francisco, and talking with the many scientists who have made important contributions to the field of ecology.

Image: Map showing areas with increased proportions of birds that are vulnerable to climate change. In red are regions with the highest proportion of birds that are sensitive to and have a low adaptive capacity to climate change and, at the same time, have the highest exposure.

Image credit: Foden WB, Butchart SHM, Stuart SN, Vié J-C, Akçakaya HR, et al. (2013) Identifying the World’s Most Climate Change Vulnerable Species: A Systematic Trait-Based Assessment of all Birds, Amphibians and Corals. PLoS ONE 8(6): e65427. doi:10.1371/journal.pone.0065427

In the deep, bioluminescent bacteria bloom bright


Imagine swimming to the bottom of the sea, the water growing impossibly deep and dark the farther you travel. At these depths, beyond the reach of the sun, live strange new sources of light. Fish, jellyfish, and even bacteria light up these midnight waters.

According to new research in PLOS ONE, the light of this deep-sea bioluminescence waxes and wanes with seasonal changes on earth’s surface. In the Mediterranean winter, cold winds cause surface water to cool. As the surface cools, it becomes denser than the water beneath it, and begins to sink. Convection can also cause this layer to expand, potentially extending it to the Mediterranean Sea’s basin floor. When these phenomena occur side by side, as they can in the northwestern part of the Mediterranean Sea, carbon matter from the surface circulates into deeper waters. Think of it as Nature’s way of stirring the pot.

This wintry stir spreads a wave of changing temperatures, water composition and organic matter into the depths of the ocean, which correlates with a burst of bioluminescence activity. Over the course of two and a half years, the researchers recorded two water stirring incidents, followed by periods of bioluminescent activity. In each instance, winter stirring resulted in bioluminescent blooms lasting several weeks in the following spring or summer.

That being said, this phenomenon is likely to change in the coming years. According to the researchers, as climate change continues to affect the sea, convection activity which helps stir the waters and introduce much-needed carbon to the deep sea may decrease by the end of the 21st century. In the meantime, it is important to document deep-sea activity to better understand any actual or forecasted changes.


Citation: Tamburini C, Canals M, Durrieu de Madron X, Houpert L, Lefèvre D, et al. (2013) Deep-Sea Bioluminescence Blooms after Dense Water Formation at the Ocean Surface. PLoS ONE 8(7): e67523. doi:10.1371/journal.pone.0067523

Image: Biolumplate, from Wikimedia Commons.

Balancing nutrient diets determines how ecosystems age

FranzGround young

From rainforests to rocky glaciers, the life of an ecosystem is rooted in the balance of nutrients in its soil. Shifting levels of soil nitrogen (N) and phosphorus (P) define how ecosystems evolve, and understanding the dynamics of these key nutrients can help ecologists identify crucial factors to help mitigate climate change.

A new model to understand N and P dynamics over different time scales was described in the PLOS ONE paper, “Nitrogen and Phosphorus Limitation over Long-term Ecosystem Development in Terrestrial Ecosystems”. Recently awarded the Ecological Society of America’s prize for an outstanding theoretical ecology paper, the study determines whether N or P are more likely to limit the productivity of ecosystems over short, intermediate and long timescales. Author Duncan Menge explains the background and results of their study:

How do N and P levels change with the age of an ecosystem like a rainforest?

A good question. Levels of both N and P are very low in very young ecosystems (which typically have rocky soils; see picture above), higher in intermediate-aged ecosystems (see picture), and often lower in old ecosystems.  How N levels change relative to P, though, is a trickier subject.  The best-studied sites show relatively low N in younger ecosystems and relatively high N in older ecosystems, but there are some places that show opposing trends.

Prior to your research, how did theoretical models assess the impact of these two nutrients on ecosystem dynamics?

Prior to our work there were a series of conceptual developments, which I will call “the classic model,” but there was no previous mathematical model of N and P dynamics during long-term ecosystem development.  The classic model states that ecosystems should progress from N deficiency in younger ecosystems to P deficiency in older ecosystems, as is seen on the best-studied sites.  According to the classic model, this happens because of the differences in where N and P come from.  P is present in most rocks, whereas N is not, so P inputs are largely controlled by the weathering of rocks.  Consequently, very young ecosystems have large P inputs, whereas very old ecosystems have small P inputs.  On the other hand, N comes primarily from rain, so N inputs don’t necessarily depend on ecosystem age.

Franz500yearsite_groundYour paper mentions that these models don’t account for several possible trajectories of ecosystem evolution. What was missing? 

There are a number of missing elements that jumped out as potentially important.  First, the input side of the story isn’t as simple as “P comes from rocks, N comes from rain.”  P also comes from dust that is blown in from upwind, whereas N can also come from organisms like soybean or alder that “fix” N from the air.  Second, N and P losses from ecosystems should be as important as inputs in determining N and P levels, but these weren’t the focus of the classic model.  These facts have been known for a long time in the scientific community, but no one had looked at what their implications might be for ecosystem development.

What was your new model and how did it cover these aspects?

Our model is novel for a couple of reasons.  First, we considered a broader set of N and P input and loss dynamics than the classic model, which made for a richer set of possible ecosystem trajectories.  Second, the type of mathematical analysis we did was unlike anything previous researchers had done in this particular field, and made it possible to pin down the types of conditions that might lead to different soil conditions.

What were some of the key data accounted for in your model that were overlooked in previous analyses?

Aside from the input and loss dynamics mentioned above, one piece of data we keyed in on was that microbes in the soil have an easier time accessing P than N in dead plant material.  Again, this “preferential P mineralization” is something that has been known for a long time, but we thought that the effects of this quirk might not be fully appreciated.

What were the main findings of your analyses?

In addition to the classic “N limitation to P limitation” path, our model shows that many other trajectories are feasible.  For example, if dust deposition is high and N-fixing organisms are abundant in young ecosystems (as they often are), an ecosystem might start out P limited and end N limited.  One of the more surprising findings was that the levels of N and P in soil organic matter (mostly dead plant material) don’t necessarily correspond to N versus P limitation in an intuitive way.

What are some of the practical applications of this model- for example, for developmental activities in rainforests, or human activities planned in other ecosystems?

Whether N or P has a greater effect in an ecosystem has important implications for many environmental issues. The most important application is enhancing our climate models.  Excess N can be transformed into a greenhouse gas, whereas P cannot.  So, a better understanding of nutrient levels will improve predictions about the extent of climate change.

Congratulations to the authors on receiving an ESA award for this outstanding research paper!

Citation: Menge DNL, Hedin LO, Pacala SW (2012) Nitrogen and Phosphorus Limitation over Long-Term Ecosystem Development in Terrestrial Ecosystems. PLoS ONE 7(8): e42045. doi:10.1371/journal.pone.0042045

Photos by Duncan Menge:

top: the rocky soil of a very young ecosystem, Franz Josef glacier in New Zealand.  The rainforests in the valley formed by the Franz Josef glacier are some of the best studied ecosystem development sites in the world.

below: a rainforest on 500 year old soil near the Franz Josef glacier.

PLOS ONE News and Blog Roundup

This January, PLOS ONE papers caught the media’s eye for research on shark embryos, trustworthy brown eyes, acts of kindness, and more! Here are some of the month’s highlights from our Media Tracking Project:

Researchers studying the brown-banded bamboo shark, or Chiloscyllium punctatum, have discovered that the baby sharks of this species can detect potential predators from inside their egg cases. Once detected, these sharks go very still and stop moving their gills to escape the predator’s notice. According to the researchers, similar ability to detect bioelectric stimuli is used by adult sharks to sense prey. If you would like to know more about this study check out the BBC, Discovery News, and the New York Times.

What makes a face look trustworthy? According to new research, eye color and face shape play important roles in the perceived trustworthiness of one’s face. Among their results, the researchers found that study participants perceived faces with brown eyes as more trustworthy than faces with blue eyes. Additionally, faces with a broad chin and mouth, large eyes, and closer-set eyebrows were perceived as more trustworthy than narrower faces with smaller eyes and more widely spaced eyebrows. For more about the study, visit the Huffington Post, Wired, and Scientific American.

Brrr! January can be quite chilly, but spring is on its way – and it might be coming earlier than anticipated. In a recent study, researchers used the historical records of Henry David Thoreau and Aldo Leopold, a noted conservationist, to trace the history of spring flowering times in the eastern United States. Beginning with records from 1852 and ending in 2012, researchers found that plants are flowering earlier now than in the past as spring temperatures continue to rise. According to their findings, there is a linear relationship between rising spring temperatures and flowering times. The researchers posit that as the climate continues to change, this relationship may be tested. To learn more about this study, read National Geographic, MSNBC, and NPR.

Being a kid can be rough sometimes, but according to this research, acts of kindness may increase happiness and lead to greater social acceptance from peers. In the study, participants aged nine to twelve were asked to perform three acts of kindness each week for four weeks. Participants who performed acts of kindness, or what the authors called “pro-social activities”, were happier and were selected by their peers as someone with whom they would like to work with at school. Read more about this study at the Washington Post, Wired, and the BBC.


RM, Hart NS, Collin SP (2013) Survival of the Stillest: Predator Avoidance in Shark Embryos. PLoS ONE 8(1): e52551. doi:10.1371/journal.pone.0052551

Kleisner K, Priplatova L, Frost P, Flegr J (2013) Trustworthy-Looking Face Meets Brown Eyes. PLoS ONE 8(1): e53285. doi:10.1371/journal.pone.0053285

Ellwood ER, Temple SA, Primack RB, Bradley NL, Davis CC (2013) Record-Breaking Early Flowering in the Eastern United States. PLoS ONE 8(1): e53788. doi:10.1371/journal.pone.0053788

Layous K, Nelson SK, Oberle E, Schonert-Reichl KA, Lyubomirsky S (2012) Kindness Counts: Prompting Prosocial Behavior in Preadolescents Boosts Peer Acceptance and Well-Being. PLoS ONE 7(12): e51380. doi:10.1371/journal.pone.0051380