What Is Causing Florida’s Algae Crisis? 5 Questions Answered
By Karl Havens
Editor's note: Two large-scale algae outbreaks in Florida are killing fish and threatening public health. Along the southwest coast, one of the longest-lasting red tide outbreaks in the state's history is affecting more than 100 miles of beaches. Meanwhile, discharges of polluted fresh water from Lake Okeechobee and polluted local runoff water from the St. Lucie and Caloosahatchee watersheds have caused blooms of blue-green algae in downstream estuaries on both coasts. Karl Havens, a professor at the University of Florida and director of the Florida Sea Grant Program, explains what's driving this two-pronged disaster.
What's the difference between red tide and blue-green algae?
Both are photosynthetic microscopic organisms that live in water. Blue-green algae are properly called cyanobacteria. Some species of cyanobacteria occur in the ocean, but blooms—extremely high levels that create green surface scums of algae—happen mainly in lakes and rivers, where salinity is low.
Red tides are caused by a type of algae called a dinoflagellate, which also is ubiquitous in lakes, rivers, estuaries and the oceans. But the particular species that causes red tide blooms, which can literally make water look blood red, occur only in saltwater.
What causes these blooms?
Blooms occur where lakes, rivers or near-shore waters have high concentrations of nutrients—in particular, nitrogen and phosphorus. Some lakes and rivers have naturally high nutrient concentrations. However, in Lake Okeechobee and the St. Lucie and Caloosahatchee estuaries, man-made nutrient pollution from their watersheds is causing the blooms. Very high levels of nitrogen and phosphorus are washing into the water from agricultural lands, leaky septic systems and fertilizer runoff.
Red tides form offshore, and it is not clear whether or to what extent they have become more frequent. When ocean currents carry a red tide to the shore it can intensify, especially where there are abundant nutrients to fuel algae growth. This year, after heavy spring rains and because of discharges of water from Lake Okeechobee, river runoff in southwest Florida brought a large amount of nutrients into near-shore waters of the Gulf of Mexico, which fueled the large red tide.
Algae is clearly visible in this satellite image of southwestern Lake Okeechobee, taken July 15.NASA Earth Observatory
The public health advisories about red tide are related to respiratory irritation, which is a particular concern for people with asthma or other respiratory issues. But almost anyone, including me, who has walked a beach where there is a red tide will quickly experience watering eyes, a runny nose and a scratchy throat. The algae that cause the red tide release a toxic chemical into the water that is easily transported into the air where waves break on the shore.
Some people are allergic to cyanobacteria blooms and can have contact dermatitis (skin rash) on exposure. Several of my colleagues have developed rashes after submerging their hands to collect water samples. It is not advisable to purposely contact water with a cyanobacteria bloom. And if farm animals or pets drink water with an intense bloom, they can become seriously ill or die.
Above video: The blooms are causing widespread fish kills and threatening Florida's tourism industry.
How can states prepare for these events?
The onset of algae blooms is unpredictable. We know high levels of nutrients allow a lake or shoreline to have blooms. We even can predict with some certainty that a bloom is likely in a particular summer—for example, if in the preceding spring heavy rainfall and runoff from the land delivered large amounts of nitrogen and phosphorus into the water.
But we can't predict exactly when a bloom will begin and end, because that depends on things we can't project. Why did the cyanobacteria bloom start in Lake Okeechobee this summer? Perhaps because there were several successive hot sunny days with little cloud cover and little wind. For some lakes in Florida and many others across the nation, we have loaded the surrounding land with so much phosphorus and nitrogen from agricultural and urban runoff that all it takes is the right weather to trigger a bloom: A rainy spring and then a few perfect sunny days in summer.
We cannot control the weather, but we can control nutrient pollution, both by reducing it at its sources and by capturing and treating water running off of large land areas. Florida has many such projects under way as part of the greater Everglades restoration efforts, but they will take decades to complete.
Nutrient pollution sources include decaying organic material; fertilizers applied to crops, lawns and golf courses; manure from fields or feedlots; atmospheric deposition; groundwater discharge; and municipal wastewater discharge. USGS
One key aspect of rehabilitating polluted lakes, rivers and estuaries is knowing whether actions are having a positive effect. This requires long-term environmental monitoring programs, which unfortunately
have been scaled back in Florida and many other states due to budget cuts.
Carefully designed monitoring could help us understand factors affecting the kind of blooms that occur and what triggers them to start and stop at particular times, and provide guidance on nutrient control strategies. We are not monitoring at that level now in Florida.
Is climate change influencing the size or frequency of these outbreaks?
Scientists have clearly shown that there is a positive and synergistic relationship between water temperature, nutrients and algal blooms. In a warmer future, with the same level of nutrient pollution, blooms will become harder if not impossible to control. This means that it is urgent to control nutrient inputs to lakes, rivers and estuaries now.
Unfortunately, today the federal government is relaxing environmental regulations in the name of fostering increased development and job creation. But conservation and economic growth are not incompatible. In Florida, a healthy economy depends strongly on a healthy environment, including clean surface waters without these harmful blooms.
Reposted with permission from our media associate The Conversation.
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The environmental disaster that Mauritius is facing is starting to appear as its pristine waters turn black, its fish wash up dead, and its sea birds are unable to take flight, as they are limp under the weight of the fuel covering them. For all the damage to the centuries-old coral that surrounds the tiny island nation in the Indian Ocean, scientists are realizing that the damage could have been much worse and there are broad lessons for the shipping industry, according to Al Jazeera.
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Transitioning to renewable energy can help reduce global warming, and Jennie Stephens of Northeastern University says it can also drive social change.
For example, she says that locally owned businesses can lead the local clean energy economy and create new jobs in underserved communities.
"We really need to think about … connecting climate and energy with other issues that people wake up every day really worried about," she says, "whether it be jobs, housing, transportation, health and well-being."
To maximize that potential, she says the energy sector must have more women and people of color in positions of influence. Research shows that leadership in the solar industry, for example, is currently dominated by white men.
"I think that a more inclusive, diverse leadership is essential to be able to effectively make these connections," Stephens says. "Diversity is not just about who people are and their identity, but the ideas and the priorities and the approaches and the lens that they bring to the world."
So she says by elevating diverse voices, organizations can better connect the climate benefits of clean energy with social and economic transformation.
Reposted with permission from Yale Climate Connections.
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If weather is your mood, climate is your personality. That's an analogy some scientists use to help explain the difference between two words people often get mixed up.
Size Matters<p>Climates are a bit like woven tapestries. The big picture is important, no question. But so are all the seemingly minor details found inside the larger whole.</p><p><a href="https://research-information.bris.ac.uk/en/persons/tommaso-jucker" target="_blank">Tommaso Jucker</a> is an environmental scientist at the University of Bristol. In an email, Jucker says he'd define the term microclimate as "the suite of climatic conditions (temperature, rainfall, humidity, solar radiation) measured in localized areas, typically near the ground and at spatial scales that are directly relevant to ecological processes."</p><p>We'll talk about that last bit in a minute. But first, there's another criteria to discuss. According to some researchers, a microclimate — by definition — must differ from the larger area that surrounds it.</p><p><a href="https://www.cfc.umt.edu/research/paleoecologylab/publications/Davis_et_al_2019_Ecography.pdf" target="_blank">Forests</a> provide us with some great examples. "The climate near the ground in a tropical rainforest is dramatically different from the climate in the canopy 50 meters [164 feet] above," says University of Montana ecologist <a href="https://www.cfc.umt.edu/personnel/details.php?ID=1110" target="_blank">Solomon Dobrowski</a> in an email. "This vertical gradient among other factors allows for the staggering biodiversity we see in the tropics."</p><p>Likewise, scientists observed that a 2015 partial <a href="https://animals.howstuffworks.com/insects/bees-stopped-buzzing-during-2017-solar-eclipse.htm" target="_blank">solar eclipse</a> caused the air temperature of an Eastern European meadow to <a href="https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/wea.2802" target="_blank">change more dramatically</a> than it did in a nearby forest. That's because trees provide not only shade, but their leaves also reflect solar radiation. At the same time, forests tend to reduce wind speeds.</p><p>All those factors add up. A 2019 review of 98 wooded places — spread out across five continents — found that forests are 7.2 degrees Fahrenheit (4 degrees Celsius) <a href="https://natureecoevocommunity.nature.com/posts/47363-forests-protect-animals-and-plants-against-warming" target="_blank">cooler on average</a> than the areas outside them.</p><p>Now if you hate the cold, don't worry; there's a cozy exception to the rule. According to that same study, forests are usually 1.8 degrees Fahrenheit (1 degree Celsius) warmer than the external environment during the wintertime. Pretty cool.</p>
A Bug's Life<p>When does a microclimate stop being, well, micro? In other words, is there a maximum size we should be aware of when discussing them?</p><p>Depends on who you ask. "In terms of horizontal scale, some have defined 'microclimate' as anything that is less than 100 meters [328 feet] in range," Jucker says. "I'm personally less prescriptive about this."</p><p>Instead, he says the "scale at which we want to measure [a particular] microclimate" ought to be "dictated" by the questions we're trying to answer.</p><p>"If I want to know how temperature affects the photosynthesis of a leaf, I should be measuring temperature at centimeter scale," Jucker explains. "If I want to know if and how temperature affects the habitat preference of a large, mobile mammal, it's probably more relevant to capture temperature variation across [tens to hundreds] of meters."</p><p>For instance, solitary plants have the power to generate itty-bitty microclimates. Just ask <a href="https://www.colorado.edu/geography/peter-blanken-0" target="_blank">Peter Blanken</a>, a geography professor at the University of Colorado, Boulder and the co-author of the 2016 book, "<a href="https://amzn.to/2XN6FT8" target="_blank">Microclimate and Local Climate</a>."</p>
The urban heat island effect is a good example of how microclimates work. NOAA
Microclimates on a Grand Scale<p>It's no secret that our planet is going through some rough times at the macro level. The global temperature is <a href="https://climate.nasa.gov/vital-signs/global-temperature/" target="_blank">climbing</a>; nine out of the <a href="https://www.noaa.gov/news/2019-was-2nd-hottest-year-on-record-for-earth-say-noaa-nasa" target="_blank">10 hottest years on record</a> have occurred since 2005. And by one recent estimate, roughly 1 million species around the world are <a href="https://ipbes.net/sites/default/files/2020-02/ipbes_global_assessment_report_summary_for_policymakers_en.pdf" target="_blank">facing extinction</a> due to human activities.</p><p>"One of the big questions that ecologists and environmental scientists are trying to answer right now is how will individual species and whole ecosystems respond to rapid climate change and habitat loss," says Jucker. "...To me, [microclimates are] a key component of this research — if we don't measure and understand climate at the appropriate scale, then predicting how things will change in the future becomes a lot harder."</p><p>Developers have long understood the impact small-scale climates have on our daily lives. <a href="https://science.howstuffworks.com/environmental/green-science/urban-heat-island.htm#pt0" target="_blank">Urban heat islands</a> are cities that have higher temperatures than neighboring rural areas.</p><p>Plants release vapors that can moderate local climates. But in cities, natural greenery is often scarce. To make matters worse, plenty of our roads and buildings have a bad habit of absorbing or re-emitting heat from the sun. <a href="https://www.google.com/books/edition/Microclimate_and_Local_Climate/LHUZDAAAQBAJ?hl=en&gbpv=1&bsq=urban%20heat%20island" target="_blank">Vehicle emissions</a> don't exactly help the situation.</p><p>Still, it's not like Boston or Beijing are thermal monoliths. Sometimes, the documented temperatures <a href="https://e360.yale.edu/features/can-we-turn-down-the-temperature-on-urban-heat-islands" target="_blank">within a single city</a> vary by 15 to 20 degrees Fahrenheit (8.3 to 11.1 degrees Celsius).</p><p>That's where metro parks and city trees come in. They have nice cooling effects on nearby neighborhoods. "Several cities around the world have developed programs to increase urban green spaces," says Blanken. "Tree planting programs and green roof programs, have been shown to lower surface temperatures, decrease air pollution and decrease surface water runoff (urban flash-flooding) in urban areas."</p>
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By Jeff Berardelli
Note: This story was originally published on August 6, 2020
If asked to recall a hurricane, odds are you'd immediately invoke memorable names like Sandy, Katrina or Harvey. You'd probably even remember something specific about the impact of the storm. But if asked to recall a heat wave, a vague recollection that it was hot during your last summer vacation may be about as specific as you can get.
<div id="ecf36" class="rm-shortcode" data-rm-shortcode-id="c2dcc9d48a6cd61f247df1544539a783"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1290959314132361216" data-partner="rebelmouse"><div style="margin:1em 0">Naming heatwaves is a good idea—making the abstract concrete, the invisible visible. Why should hurricanes and wild… https://t.co/hDWgYb79Ob</div> — Ed Maibach (@Ed Maibach)<a href="https://twitter.com/MaibachEd/statuses/1290959314132361216">1596623660.0</a></blockquote></div>
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