Binational Pact can Revive Colorado River Delta
What happens when a river no longer runs to the sea?
In August 2010, my documentary film crew and I explored the Colorado River's dry riverbed from the Mexican border to its mouth in the Gulf of California as a part of our Expedition Blue Planet: North America project. What we witnessed was the eerie ghost of a mighty river that once carried water, rich silts and prosperity on its way to connect with the sea my grandfather Jacques-Yves Cousteau called “the world's aquarium" and the “Galapagos of North America." Sadly, with the exception of a few extraordinarily wet seasons, the nutrient-rich waters of the Colorado have not completed their journey to the sea in decades.
Along the way, we worked with leading scientists and met locals who told us about the birds, wildlife and trees that disappeared; about the once-abundant fish that no longer thrive; and a way of life that is vanishing with the fisheries. A land of forests and emerald lagoons just 80 years ago has become a salted mud flat and desert.
The explanation for this collapse is no mystery. Before it ever reaches the border with Mexico, 90 percent of the water in the Colorado is diverted for use by seven Colorado River basin states. At the border, Mexico's Morelos Dam diverts what's left to agriculture and cities like Tijuana and Mexicali. And after that, there is hardly a trickle left to keep critical natural systems operating across the once-rich riverbed. From the border to the sea, the Colorado is a river no more.
After the April 2010 Mexicali earthquake, which damaged local infrastructure and irrigation canals in northwest Mexico, the U.S. agreed to temporary storage of a small percentage of Mexico's allocation—water that Mexico could not use due to the earthquake damage—for the first time allowing our river partners to take advantage of storage behind U.S. dams.
Additionally, during a trial run of the Yuma Desalting Plant in Arizona, the two countries collaborated to protect critical wetlands at the internationally recognized 40,000-acre Ciénega de Santa Clara in Mexico. The Ciénega relies entirely on Colorado River water from agricultural drainage to form the last remaining wetland in the Delta and a critical habitat for millions of water birds and shorebirds. Deprived of life-giving flows during the pilot run, the Ciénega would have suffered irreparable damage.
The U.S. and Mexico are now negotiating a new cooperative agreement to improve Colorado River management. To accomplish a final U.S.-Mexico agreement, it is critical that both nations agree to provide basic flows to the disappearing Colorado River Delta. The conservation community urges Interior Secretary Ken Salazar and the Obama administration to see this pivotal agreement to completion as quickly as possible. Salazar has repeatedly demonstrated his mastery of collaborative alliance and we look forward to a successful outcome here.
At stake is water security for both nations. Most importantly it would establish more equitable management of water during droughts, reducing the impact of shortages on water users in both countries.
With a modest water supply, life will continue to flourish in the Delta and increasingly return along the river below the last dam. But our leaders must act together to bring back life-giving flows to the Colorado River Delta.
The time is now. Desert river deltas are famous for their diversity, and critical for all life along their pathways. The Colorado River Delta is the critical “waistline in the hourglass" of the Pacific Flyway, a major continental migratory route for birds. Its mud flats and estuary zone create an irreplaceable food stock for the fisheries that are an important source of income for communities throughout the region.
As a completed system, the Colorado River represents one of the most impressive and important mountains-to-canyons-to-sea natural corridors on our continent—one we'd be foolish and selfish to not preserve for our children. Without a thriving Delta, we trade away a natural system that supplies life and resiliency to both nations. In this election season of political rancor, it's important to keep pushing forward with this historic collaboration—to seal in water our promise to work together for a prosperous and vibrant future.
EcoWatch Daily Newsletter
Mangroves play a vital role in capturing carbon from the atmosphere. Mangrove forests are tremendous assets in the fight to stem the climate crisis. They store more carbon than a rainforest of the same size.
- Protecting Mangroves Can Prevent Billions of Dollars in Global ... ›
- Could the 'Mangrove Effect' Save Coasts From Sea Level Rise ... ›
Monday is World Oceans Day, but how can you celebrate our blue planet while social distancing?
- 5 Things to Know About Earth's Warming Oceans - EcoWatch ›
- Bioluminescent Waves Mesmerize California Beachgoers, Surfers ... ›
- NOAA: 2020 Could Be Warmest Year on Record - EcoWatch ›
- On June 8, We Celebrate Our Oceans, Our Future - EcoWatch ›
- 5 Things to Know About the State of Our Oceans for World Oceans Day ›
By Jacob L. Steenwyk and Antonis Rokas
From the mythical minotaur to the mule, creatures created from merging two or more distinct organisms – hybrids – have played defining roles in human history and culture. However, not all hybrids are as fantastic as the minotaur or as dependable as the mule; in fact, some of them cause human diseases.
When Looking Through a Microscope Isn’t Close Enough.<p>For the last few years, <a href="http://www.rokaslab.org/" target="_blank">our team at Vanderbilt University</a>, <a href="https://www.researchgate.net/lab/Gustavo-Goldman-Lab" target="_blank">Gustavo Goldman's team at São Paulo University in Brazil</a> and many other collaborators around the world have been collecting samples of fungi from patients infected with different species of <em>Aspergillus</em> molds. One of the species we are particularly interested in is <a href="https://doi.org/10.1006/rwgn.2001.0082" target="_blank"><em>Aspergillus nidulans</em>, a relatively common and generally harmless fungus</a>. Clinical laboratories typically identify the species of <em>Aspergillus</em> causing the infection by examining cultures of the fungi under the microscope. The problem with this approach is that very closely related species of <em>Aspergillus</em> tend to look very similar in their broad morphology or physical appearance when viewing them through a microscope.</p><p>Interested in examining the varying abilities of different <em>A. nidulans</em> strains to cause disease, we decided to analyze their total genetic content, or genomes. What we saw came as a total surprise. We had not collected <em>A. nidulans</em> but <em>Aspergillus latus</em>, a close relative of <em>A. nidulans</em> and, as we were to soon find out, <a href="https://doi.org/10.1016/j.cub.2020.04.071" target="_blank">a hybrid species that evolved through the fusion of the genomes</a> of two other <em>Aspergillus</em> species: <em>Aspergillus spinulosporus</em> and an unknown close relative of <em>Aspergillus quadrilineatus</em>. Thus, we realized not only that these patients harbored infections from an entirely different species than we thought they were, but also that this species was the first ever <em>Aspergillus</em> hybrid known to cause human infections.</p>
Several Different Fungal Hybrids Cause Human Disease.<p>Hybrid fungi that can cause infections in humans are well known to occur in several different lineages of single-celled fungi known as yeasts. Notable examples include multiple different species of <a href="https://doi.org/10.1002/yea.3242" target="_blank">yeast hybrids</a> that cause the human diseases <a href="https://rarediseases.info.nih.gov/diseases/6218/cryptococcosis" target="_blank">cryptococcosis</a> and <a href="https://www.cdc.gov/fungal/diseases/candidiasis/index.html" target="_blank">candidiasis</a>. Although pathogenic yeast hybrids are well known, our discovery that the <em>A. latus</em> pathogen is a hybrid is a first for molds that cause disease in humans.</p>
(Left) Candida yeasts live on parts of the human body. Imbalance of microbes on the body can allow these yeasts, some of which are hybrids, to grow and cause infection. (Right) Cryptococcus yeasts, including ones that are hybrids, can cause life-threatening infections in primarily immunocompromised people. Centers for Disease Control and Prevention<p><a href="https://doi.org/10.1371/journal.ppat.1008315" target="_blank">Why certain <em>Aspergillus</em> species are so deadly</a> while others are harmless remains unknown. This may in part be because <a href="https://doi.org/10.1016/j.fbr.2007.02.007" target="_blank">combinations of traits, rather than individual traits</a>, underlie organisms' ability to cause disease. So why then are hybrids frequently associated with human disease? Hybrids inherit genetic material from both parents, which may result in new combinations of traits. This may make them more similar to one parent in some of their characteristics, reflect both parents in others or may differ from both in the rest. It is precisely this mix and match of traits that hybrids have inherited from their parental species that <a href="https://www.nytimes.com/2010/09/14/science/14creatures.html" target="_blank">facilitates their evolutionary success</a>, including their ability to cause disease.</p>
The Evolutionary Origin of an Aspergillus Hybrid.<p>Multiple evolutionary paths can lead to the emergence of hybrids. One path is through mating, just as the horse and donkey mate to create a mule. Another path is through the merging or fusion of genetic material from cells of different species.</p><p>It is this second path that appears to have been taken by our fungus. <em>A. latus</em> appears to have two of almost everything compared to its parental species: twice the genome size, twice the total number of genes and so on. But unlike other hybrids, which are often sterile like the mule, we found that <em>A. latus</em> is capable of reproducing both asexually and sexually.</p><p>But how distinct were the parents of <em>A. latus</em>? By comparing the parts contributed by each parent in the <em>A. latus</em> genome, we estimate that its parents are approximately 93% genetically similar, which is about as related as we humans are with lemurs. In other words, <em>A. latus</em>, an agent of infectious disease, is the fungal equivalent of a human-lemur hybrid.</p>
How A. Latus Differs From its Parents.<p>Elucidating the identity of closely related fungal pathogens and how they differ from each other in infection-relevant characteristics is a key step toward reducing the burden of fungal disease. For example, we found that <em>A. latus</em> was three times more resistant than <em>A. nidulans</em>, the species it was originally identified as using microscopy-based methods, to one of the most common antifungal drugs, <a href="https://www.drugbank.ca/drugs/DB00520" target="_blank">caspofungin</a>. This result provides a clear example of the potential importance of accurate identification of the <em>Aspergillus</em> pathogen causing an infection.</p><p>We also examined how <em>A. latus</em> and <em>A. nidulans</em> interact with cells from our immune system. We found that immune cells were less efficient at combating <em>A. latus</em> compared to <em>A. nidulans</em>, suggesting the hybrid fungus may be trickier for our immune systems to identify and destroy.</p><p>In the midst of the COVID-19 pandemic, our quest to understand <em>Aspergillus</em> pathogens is becoming more urgent. Growing evidence suggests that <a href="https://doi.org/10.1111/myc.13096" target="_blank">a fraction of COVID-19 patients are also infected with <em>Aspergillus</em>.</a> More worrying is that these <a href="https://doi.org/10.3201/eid2607.201603" target="_blank">secondary <em>Aspergillus</em> infections</a> can worsen the clinical outcomes for those infected with the novel coronavirus. That being said, we stress that little is known about <em>Aspergillus</em> infections in COVID-19 patients due to a lack of systematic testing, and none of the infections identified so far appear to have been caused by hybrids.</p><p>So, when it comes to hybrids, some are fantastic (the minotaur), some are helpful (the mule) and some are dangerous (<em>Aspergillus latus</em>). Understanding more about the biology of <em>Aspergillus latus</em> may help in our understanding of how microbial pathogens arise and how to best prevent and combat their infections.</p>
This Saturday, June 6, marks National Trails Day, an annual celebration of the remarkable recreational, scenic and hiking trails that crisscross parks nationwide. The event, which started in 1993, honors the National Trail System and calls for volunteers to help with trail maintenance in parks across the country.
- As Protests Rage, Climate Activists Embrace Racial Justice ... ›
- First-Ever Black Birders Week Tackles Racism Outdoors - EcoWatch ›
- 15 EcoWatch Stories on Environmental and Racial Injustice ... ›
- Take a Hike Day Is Around the Bend. What's Your Dream Hike ... ›
By John Letzing
This past Wednesday, when some previously hard-hit countries were able to register daily COVID-19 infections in the single digits, the Navajo Nation – a 71,000 square-kilometer (27,000-square-mile) expanse of the western US – reported 54 new cases of what's referred to locally as "Dikos Ntsaaígíí-19."
The Navajo Nation covers the corners of three different states. Google Maps
Growing Contribution<img lazy-loadable="true" src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzM3NDY5Ny9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY0NjM4MTgyM30.IuQTKQs1stvYYKD6vaVTrqAyoBsUG0BhDvlhxsyKwPA/img.png?width=980" id="02a05" class="rm-shortcode" data-rm-shortcode-id="2841f82b1785df5d5ed7bf64d3bb882b" data-rm-shortcode-name="rebelmouse-image" />
World Economic Forum
- Black and Hispanic Americans Suffer Disproportionate Coronavirus ... ›
- Native American Tribes' Pandemic Response Is Hindered by ... ›
- Navajo Nation Has Highest Covid-19 Infection Rate in the U.S. ... ›
World Environment Day: A Time to Consider the Planet We’ll Return To, and Decide How to Care for It Going Forward
It's a different kind of World Environment Day this year. In prior years, it might have been enough to plant a tree, spend some extra time in the garden, or teach kids the importance of recycling. This year we have heavier tasks at hand. It's been months since we've been able to spend sufficient time outside, and as we lustfully watch the beauty of a new spring through our kitchen's glass windows, we have to decide how we'll interact with the natural world on our release, and how we can prevent, or be equipped to handle, future threats against our wellbeing.
Scuba divers around the world are holding their metaphorical breath to see if a coronavirus infection affects the ability to dive.
DAN medical experts explained the difference between normal lungs, on the left, and "very serious lungs caused by COVID-19," on the right. Matias Nochetto / Divers Alert Network (DAN)
- How the COVID-19 Coronavirus Attacks the Entire Body - EcoWatch ›
- What Does 'Recovered From Coronavirus' Mean? - EcoWatch ›
- Scuba Divers Make Face Masks out of Recycled Ocean Plastic ... ›