Medellin R.A.,National Autonomous University of Mexico |
Wiederholt R.,Everglades Foundation |
Lopez-Hoffman L.,University of Arizona
Biological Conservation | Year: 2017
All ecosystems are dotted by salient small natural features that not only characterize them but also significantly add to their biodiversity and functions. These small natural features are prominent but easily missed when ecosystems are described. Caves are one key example of this. Cave ecosystems are underrepresented in conservation planning and implementation around the world and have become mostly overlooked in conservation strategies overall. Caves contain high levels of biodiversity from fungi to invertebrates to vertebrates. This paper emphasizes bat caves as providers of ecosystem services to vast areas surrounding them, in the order of hundreds of thousands of square km just in North America. Their influence extends three-dimensionally via subterraneous water bodies and via the aerial nightly dispersal of the bats that provide a host of services from seed dispersal to pollination to pest control. The examples used focus primarily on free-tailed bats in North America, but the same principles apply to any other cave in the world with significant bat colonies. Caves enjoy protection, legal or actual, in some countries and not in others, and as a result many have suffered damage or been destroyed altogether. Common threats are vandalism, urbanization, and pollution. Many caves are attractive as ecotourism destinations and provide unique opportunities to educate the public about unexpected biodiversity values and ecosystem services. Inventorying caves poses challenges, but efforts are under way to assess caves in need of protection. Incipient cave protection strategies include legal and educational efforts, and management. Although illustrated with bat caves, given the importance of all caves and their precarious status, it is time to call the attention of decision makers about the urgent need to launch a worldwide cave conservation initiative. © 2017 Elsevier Ltd.
News Article | February 22, 2017
MARYSVILLE, Ohio, Feb. 22, 2017 (GLOBE NEWSWIRE) -- On the cusp of its 150th anniversary, The Scotts Miracle-Gro Company today announced the formation of a charitable foundation with a core focus on environmental issues, the creation of community gardens and greenspaces and the development of high-potential, underserved students through education. “This decision is a testament to our culture and our proud history of supporting the environment and the communities where we live and work,” said Jim Hagedorn, chairman and CEO. “As we prepare to celebrate our 150th anniversary, this is the right time to create a foundation. Such a milestone should do more than simply reflect on where we’ve been, it should focus on where we’re headed. The creation of The Scotts Miracle-Gro Foundation marks a long-term commitment to a series of important causes we hold dear and that we trust the next generation of leaders and associates will proudly build upon.” One of the first major programs to be supported by the Foundation will take place March 22, which is World Water Day. The Scotts Miracle-Gro Foundation and The Everglades Foundation will co-sponsor a national Impact and Innovation Water Summit, which will address concerns around the growing problem of water nutrient pollution, particularly from excess phosphorus in waterways. The event, which will be held in Florida where nutrient issues have become a significant concern, will mark a formal collaboration from both groups towards supporting bold and lasting designs for water protection. Summit attendees will include representatives from the public and private sector, academic experts on water quality issues, as well as other water-related environmental organizations from across the U.S., including a dozen charitable organizations whose work The Scotts Miracle-Gro Foundation will also fund. "Supporting water quality and conservation issues is the most important environmental priority for our Company, so it’s fitting that it be the first major focus of our new Foundation," said Foundation President and Board Member Jim King who also serves as SVP and Chief Communications Officer for ScottsMiracle-Gro. “But achieving clean, abundant water is a challenge much broader than what our company or industry can solve for alone. We hope that our support of The Everglades Foundation and other environmental groups will help advance the cause of preserving the beauty and health of our waterways.” The Scotts Miracle-Gro Foundation will also support The Hagedorn Legacy Foundation on a new program that identifies and nurtures high-potential, underserved students in Central Ohio. The program’s goal is to change the future of these at-risk students by helping them achieve social mobility through mentoring and educational opportunities. Details about the new initiative will be unveiled later in 2017 with an anticipated program launch in 2018. The Foundation also will dedicate resources to establish gardens and outdoor spaces in the communities that need them the most. This creation of outdoor spaces will be accomplished by bolstering GRO1000, a multi-year effort to bring the life-enhancing benefits of gardens and greenspaces to communities across the United States. “Current and future generations deserve access to gardens and greenspaces, clean water resources and the dream of a better life,” said Foundation Board Member Jim King. “We will work diligently to help tackle large, complex issues through our Foundation giving. Through our support of like-minded partners, our mission is to spark positive social and environmental change and create a lasting legacy.” The mission of The Scotts Miracle-Gro Foundation is to inspire, connect and cultivate communities of purpose in the areas of environmental improvement, youth empowerment, and community gardens and greenspaces. The Foundation carries out its mission by funding qualifying charitable entities that support its core initiatives in the form of grants, endowments, and multi-year capital gifts. The Foundation is deeply rooted in preserving our planet, empowering the next generation, and helping create healthier communities. For more information, visit www.scottsmiraclegrofoundation.org
News Article | November 17, 2016
MIAMI--(BUSINESS WIRE)--SeaWorld Parks & Entertainment and The Everglades Foundation, Inc. announced a new partnership focused on educating young Floridians about the importance of saving America’s Everglades.
News Article | February 27, 2017
The Comprehensive Everglades Restoration Plan, the world's largest ecosystem restoration project, has made little progress since it was launched in 2000 (AFP Photo/RHONA WISE ) Miami (AFP) - Rising seas, polluted coastlines and the specter of more frequent droughts and storms have lent new urgency to efforts to restore the ecosystem of the Florida Everglades, the largest freshwater wetland in the United States. The Everglades' sawgrasses, swamps, tree islands and mangroves are home to a host of fascinating species, from American alligators to endangered hook-billed birds known as snail kites to invasive Burmese pythons. Until now, the world's largest ecosystem restoration project -- a massive plan expected to spend some $10.5 billion, known as the Comprehensive Everglades Restoration Plan -- has made little progress since it was launched in 2000. "Our goal was to have much of it done in 20 years," said Steve Davis, a wetlands ecologist with the Everglades Foundation, who led reporters on an airboat tour of the Everglades this month. "We are almost 20 years in and we don't have a single project completed." Even though the Everglades is known as the River of Grass, the water has not properly flowed through it in the past 70 years or so, because human development cordoned off the freshwater which used to spill over from Florida's massive Lake Okeechobee toward the south. As millions of people poured into the Sunshine State, a dike was built to protect against hurricane flooding and swamps were drained to make way for sugar cane farms. About one third of the Everglades' original three million acres (405,000 of 1.2 million hectares) became farmland, and 1.5 million acres were designated a national park. "We altered the ecosystem back in the '40s and '50s when we didn't know any better," said Bob Johnson, a hydrologist with the National Park Service. "Now we have to fix it." The consequences of diverting Lake Okeechobee's water -- much of it polluted by agricultural discharge -- to the east and west have grown increasingly dire. Last year, algae blooms coated the coastline with smelly, guacamole-colored sludge, and swimmers were warned to stay out of the water due to outbreaks of poisonous bacteria. Meanwhile, the spread of hot and salty water off the southern tip of Florida killed fertile fish breeding grounds known as seagrasses, threatening tourism and fishing -- two key drivers of the state economy. "There is simply not enough water coming in from the north to keep the entire system hydrated from top to bottom," said Davis. The movement of freshwater from the lake toward the south must be restored if the area's tourist economy, drinking water and natural and developed lands are to be sustained in the years to come, he said. Without some two million more acre feet -- an old measure devised by imagining a foot of water on an acre (0.4 hectare) of land -- of freshwater to drench the Everglades, the marshes dry out, the thin layer of peat covering the porous limestone ground dissipates or even burns under the hot sun, and the landscape flattens making it easier for saltwater to invade, Johnson told a meeting of the Tropical Audubon Society this month. Saltwater intrusion is already making its way into parts of Florida's aquifers -- which provide drinking water -- and could forever alter the Everglades' fragile ecosystem. Having more freshwater in the system could help because it "pushes against the saltwater and keeps those marshes wet," explained Johnson. "It helps stave off the effects of sea level rise." Scientists like Davis and Johnson say the solution requires having more land south of the lake -- an area filled with sugar cane farms -- to use as storage reservoirs where water can be cleaned before flowing south. "If we don't figure out how to store more water, we can't get through the problems to come. We can't get through long droughts and then very intense rainfall," said Johnson. After years of political squabbles, there are signs that lawmakers are motivated to fix the problem. Bills have been newly introduced in the Florida House and Senate to authorize over one billion in state dollars to acquire 60,000 acres of land for a reservoir south of Lake Okeechobee that would hold 120 billion gallons (454 billion liters) of water. But more than a dozen farming companies in the area have dug in their heels, including sugar giants US Sugar and Florida Crystals, saying they are not willing to sell, questioning the science behind the proposals, and warning of job losses if land acquisition goes ahead.
News Article | April 27, 2016
EVERGLADES NATIONAL PARK, Florida — The shallow coastal waters of Florida Bay are famed for their crystal clear views of thick green seagrass – part of the largest stretch of these grasses in the world. But since mid-2015, a massive 40,000-acre die off here has clouded waters and at times coated shores with floating dead grasses. The event, which has coincided with occasional fish kills, recalls a prior die-off from 1987 through the early 1990s, which spurred major momentum for the still incomplete task of Everglades restoration. “It actually started faster as far as we can tell this year,” said James Fourqurean, a Florida International University marine scientist who studies the system. “In the ’80s, it continued to get worse for 3 years.” Fourqurean and government Everglades experts fear they’re witnessing a serious environmental breakdown, one that gravely threatens one of North America’s most fragile and unusual wild places. When most people think of the Everglades, they envision swamps — but seagrass is just as important, if less romanticized. Besides being the home to majestic sea turtles, dolphins, and manatees, Florida Bay also hosts pink shrimp, spiny lobsters, spotted seatrout, and much more – sport fishing alone here is worth $ 1.2 billion per year, according to the Everglades Foundation. And although there is at least some scientific dissent, Fourqurean and fellow scientists think they know the cause of the die-off. It’s just the latest manifestation, they say, of the core problem that has bedeviled this system for many decades: Construction of homes, roads, and cities has choked off the flow of fresh water. Without fast moves to make the park far more resilient to climate change and rising, salty seas, the problem will steadily worsen. The Everglades ecosystem “being out of balance at a time of climate change is really going to have a huge impact on South Florida, if we don’t do something about it,” said Interior Secretary Sally Jewell, who surveyed the seagrass die-off last week during an Everglades Trip. Holding dead grasses in her hand in a National Park Service boat in the more than half-a-million-acre estuary, Jewell told a group of staff and reporters, “This is what we get when we don’t take care of Florida Bay.” Florida Bay encompasses roughly one-third of Everglades National Park. And like the park’s mangroves and sawgrass prairies, it relies on the same broad water system. Both need fresh water to flow southward from Florida’s Lake Okeechobee, and the central part of the state, to preserve their unique characteristics. And both have suffered from highway and water management projects that have blocked or diverted much of this water away. “It’s basically a permanent manmade drought, created by the drainage and development patterns to the north in the Everglades,” said Robert Johnson, director of the National Park Service’s South Florida Natural Resources Center, on the boat trip with Jewell. The seagrass die off, according to Johnson, was caused when this perennial problem was further exacerbated by a 2014-2015 South Florida drought. Flows through Shark River Slough, which feeds water to the Everglades and eventually Florida Bay, plunged to just 200,000 acre-feet in 2015. That’s just a quarter of standard annual flows, which themselves are less than half of historic flows of 2 million acre-feet per year before major projects blocked and redirected the Everglades’ water. The center of the bay then heated up last summer, saw considerable evaporation, and became quite salty – for some parts of the bay, twice as salty as normal sea water. “It’s a really delicate balance between how much freshwater comes in each year, how much rainfall falls, and then how much evaporation occurs,” Johnson said. “In the absence of rainfall, salinity takes off in the bay, and we get a lot of harmful impacts of that.” In very salty conditions, waters hold little of the oxygen that seagrasses need to live. At the same time, other marine organisms turn to a different “anoxic” process – one that goes forward without oxygen – that has a nasty by-product: hydrogen sulfide. The chemical “is a notorious toxin,” said Donald Boesch, president of the University of Maryland Center for Environmental Science. “It kills life, including human.” And that’s just the beginning. Once the seagrass dies off, it becomes a feedback – the water becomes filled with dead grasses that release nutrients, and those can stoke huge algal blooms (which happened the last time around, but so far have not appeared en masse). That clouds the water and prevents light from reaching remaining seagrasses, which then also die, because they need the light for photosynthesis. “You have this water that’s notoriously gin clear water, because the seagrasses and the biology kept the light penetrating, and then all of a sudden it changes pretty dramatically to a system without grass, and very turbid waters,” Boesch said. Granted, there are some dissenters. Brian LaPointe, a researcher with Florida Atlantic University, contends that Florida Bay seagrass die-offs are caused by the runoff of too many nutrients, like nitrogen, into the Bay’s waters, which in turn stoke algal blooms. “There really isn’t a correlation over time of high salinity and problems in the Bay,” LaPointe said. Seagrasses, he said, “can handle pretty high salinities.” During the last dieoff, a large scientific debate erupted over whether changes in salinity were indeed the cause. But Boesch, who led a scientific review of the last die-off during the Clinton administration (which failed to reach a conclusion at the time), said that the high-salinity explanation “has now become kind of the mainstream scientific explanation,” although that now encompasses other related processes involving oxygen content of waters and buildup of hydrogen sulfide. It’s not just Florida Bay: Seagrasses the world over are threatened. In a 2009 study, scientists found that segrass extent had declined globally by 29 percent since the late 19th century. They concluded that seagrasses were just as threatened as their companion coastal ecosystem, coral reefs, though the latter tend to get far more attention. The Obama administration, in collaboration with Florida state agencies and local leaders, has been moving lately to simultaneously restore historic Everglades water flows and to try to safeguard the park against climate change. President Obama visited last year, telling his audience that “You do not have time to deny the effects of climate change…nowhere will it have a bigger impact than here in South Florida.” And this year Jewell visited the Everglades on Earth Day to announce a $ 144 million “bridging” project that will elevate 2.5 miles of Highway 41, more popularly known as the Tamiami Trail, which connects Miami to Tampa and runs through the Everglades. Constructed in the 1920s, the highway impairs water flow southward, from Lake Okeechobee, into the Everglades (and, eventually, the Bay). It’s like a dam across the famed “river of grass.” Lifting it could restore a substantial part of historic freshwater flow levels. But that will take years – the project should be completed in 2020 — too long to stop the current seagrass die off from running its course and perhaps having many cascading effects, scientists fear. And it’s not just nature that needs this fresh water: It’s people. South Florida, the home to 6 million people now and growing steadily, relies on the Biscayne aquifer, which is refilled by the Everglades, for drinking water. The aquifer’s water flows through limestone that is quite porous, which means that saltwater and freshwater can both penetrate it. In effect, two walls of water abut one another, facing off — and for the sake of nature and people alike, freshwater needs to hold its ground. If inadequate freshwater flows southward in Florida, then Florida Bay can get too salty even as the seas also creep into the Everglades, potentially causing land to subside and sink – but also penetrating the aquifer and threatening drinking water. In short, it’s bad news across the whole system. And even as governments at the local, state, and national level move faster to send the Everglades and the Bay more fresh water, the question remains just how much climate change will worsen problems like the seagrass die-off. After all, it will raise seas, increase air and water temperatures, and perhaps drive more droughts as well. “The questions I would ask, from a climate perspective, going forward, is first of all, are we going to have more conditions of really high temperature, due to, you know, the atmospheric warming, coupled with these extended periods of still water?” Boesch said. “Are we going to have longer periods of drought in the Everglades?” Boesch said that while higher temperatures are a given, precipitation patterns are difficult to predict, but notes that there is some reason to fear South Florida could get drier in the future. “What happened to the Bay is very much a climate change issue,” Jewell said in an interview during her Everglades tour. “It’s tied in to a drought. Now, is the drought tied to climate change? None of us could tie any single hurricane or storm event or drought to climate change, but we do know that the weather here is getting more extreme. And we do know that those extreme weather patterns are having a dramatic impact on our ecosystems, as we saw today on Florida Bay.” Still, much of Florida Bay remains unaffected – for now. That includes an area of lush seagrass meadow near a small island named Johnson Key. A trio of bottlenosed dolphins approached the National Park Service skiff there, and as the boat trolled slowly through the clear, only 3- to 4-foot-deep water, started to lead the way ahead of it. Nonetheless, the second major seagrass die off in three decades certainly suggests that something has changed recently in the system. “The really disturbing thing is, this unprecedented event has now happened twice in my career,” Fourqurean said. Six years later, we’re still learning how badly the BP spill damaged the environment This key psychological factor could explain why you care about the environment These striking numbers show just how fast we’re switching off coal For more, you can sign up for our weekly newsletter here, and follow us on Twitter here.
News Article | December 5, 2016
Palmetto Bay, Fla. - In a bold effort to find a solution to one of the world's most challenging environmental problems, The Everglades Foundation (The Foundation) will officially kick off its four-year, $10-million George Barley Water Prize at the "Tapping Innovation: Breakthrough Thinking, Action & Awards" event on Wednesday, December 7, 2016, at 6 p.m., at the Miami Science Barge, located at 1075 Biscayne Boulevard, Miami, FL. The event, sponsored by the Knight Foundation, will feature a distinguished group of water experts discussing the problem of excess nutrients, like phosphorus and nitrogen, causing toxic algae blooms, which foul drinking water, drive delicate ecosystems toward collapse, and annually cost the United States between $2.2 billion and $4.6 billion. The Foundation will also provide attendees a tour of the Miami Science Barge, a floating environmental innovation lab. The prize competition, named in honor of the late Florida environmentalist George Barley, is designed to incentivize free-market solutions to the increasingly urgent algae bloom problem, which impacted about 15,000 water bodies worldwide in 2016, including those in at least 20 U.S. states. The George Barley Water Prize marks the largest cash award ever offered in the field of water stewardship and has already attracted 147 teams from around the world, each striving to discover an innovative and cost-effective solution to remove phosphorus from our lakes, rivers and major freshwater bodies. At the December 7 event, The Foundation will reveal the winners of the first two phases of Stage 1 of the competition - whose technological innovations, thus far only tested on a small scale, could perhaps go on to win the larger prize and ultimately provide the world with a solution that could reverse the environmental damage done to water bodies as large as Lake Erie. "We are excited to officially kick off this unique opportunity for global impact," said Eric Eikenberg, CEO of The Foundation. "The world badly needs a solution to this problem. It has eluded governments and private industry, but we know there are some incredibly inventive entrepreneurs out there who want to apply their expertise to this issue. The competition's four-year timetable allows for the development, testing and production of a phosphorus-removal technology that's ready to solve a local-to-global environmental problem. The first two phases of Stage 1 brought many compelling and innovative ideas to the table and we look forward to seeing what the next stage ushers in as the competition progresses." For more information on the competition, please visit BarleyPrize.com. To learn more about the prize, the algae bloom problem or connect with our team, please contact Sonia Rodriguez at 305.251.0001 or firstname.lastname@example.org.
News Article | October 19, 2016
WEST PALM BEACH, Fla., Oct. 19, 2016 (GLOBE NEWSWIRE) -- Recognizing the importance of protecting the environment, particularly protecting Florida’s water resources, Scotts today announced it has introduced new 50 percent slow-release nitrogen lawn food products throughout the entire state of Florida. This unique-to-Florida lawn fertilizer will help consumers play a role in protecting the state’s critical water resources. In properly caring for the lawns around their homes, these spaces can act as barriers to counteract the many sources of urban nutrient runoff. The product innovation builds on Scotts’ nationwide phosphorus-free lawn maintenance fertilizer initiative completed in 2013 as well as a multi-year Smarter Solutions for Cleaner Waterways initiative that began in 2014 and culminates this year. “As leaders in lawn and garden, we have an on-going commitment to innovation that helps gardeners nurture plant life in ways that work in harmony with the world around them,” said Jim Hagedorn, Chairman and CEO of parent company ScottsMiracle-Gro, who is a resident of Florida. “Florida’s water bodies make our state a truly amazing place and we view it as our responsibility to help Floridians be confident that they are doing their part to protect our most valuable natural resources. We began a three-year program in 2014 that dedicated support for groups conducting research, restoration and greenspace projects around many of the state’s most sensitive water bodies and will expand this work with environmental leaders across the state beyond 2016.” More than five years ago, Scotts made the groundbreaking announcement that it would remove phosphorus from all its lawn maintenance products nationwide in order to improve the environmental impact of its lawn care products. This innovation lead to a 10,000 ton reduction in phosphorus use nationwide, leading to an approximate 500 ton reduction annually in Florida. The introduction of 50 percent slow-release nitrogen products to the entire state of Florida signals a new milestone in the Company’s national “Water Positive Landscapes” initiative aimed at protecting waterways by providing homeowners with actionable ways to responsibly use water when working in their lawns and gardens. “Water quality remains a concern throughout Florida as algae blooms increasingly threaten the health of Florida’s water bodies,” said Josh Peoples, Vice President and General Manager of Scotts brand products. “We have taken this step to continue our pursuit to provide consumers the best products for their lawns so that they can that positively impact the environment around them.” “We have watched ScottsMiracle-Gro prove they are committed to being part of the solution in restoring water bodies like the Everglades by removing phosphorus from their products years ago and, now, in taking another important step to help residents across Florida improve their nitrogen footprint when working in their own yards. The Everglades Foundation applauds Scotts’ ongoing efforts to implement nutrient solutions in our state,” said Eric Eikenberg, CEO of the Everglades Foundation. This will be the first 50 percent slow release nitrogen product that uses Scotts’ patented All-In-One Particle® technology for even feeding across lawns. When nutrients, such as nitrogen, are slowly released over an extended period of time, it enables lawns to stay consistently healthy and properly serve as a barrier to runoff particularly during heavy rains, such as the ones that occur during Florida’s summers. More than $8 million and five years were invested into the research necessary to develop a reliable slow release nitrogen technology, uniquely designed with Florida’s climate, sandy soil composition and year-round gardening in mind. “There is simply no question about whether or not the level of nutrients, particularly phosphorus and nitrogen, in our waterways is contributing to the problems we are seeing in the Indian River Lagoon and other water bodies,” said Dr. Edith “Edie” Widder, Founder of the Ocean Research and Conservation Association (ORCA). “Providing Floridians with a means for reducing their environmental footprint will go a long way to restoring the health of these delicate and precious ecosystems.” Furthering the Commitment to Innovation and Environmental Stewardship In June, ScottsMiracle-Gro announced a nationwide Water Positive Landscapes initiative, which is equipping homeowners with educational and actionable resources to help them use water responsibly in their lawns and gardens. The initiative is also focusing on product innovation, such as 50 percent slow release nitrogen, and continued research on the intersection between lawn care and gardening and water stewardship. This latest water protection initiative follows the Company’s "Florida Smarter Solutions for Cleaner Waterways” initiative that sponsored in-state water quality research, habitat restoration, consumer education and green infrastructure improvements. ScottsMiracle-Gro funded an independent research project by the Ocean Research & Conservation Association to determine the sources of pollution in the Indian River Lagoon. The results of this research will help create solutions to improve the lagoon’s water and wildlife, and also create a model that can be replicated for other polluted waterways. Through its partnership with Tampa Bay Watch, more than 20 acres of salt marsh plants will be restored in Tampa Bay. Grants to community gardens, farms and greenspaces throughout Florida have protected more than 47,600 square feet of land. “As a partner in the ScottsMiracle-Gro ‘Florida Smarter Solutions for Cleaner Waterways’ initiative and a participant in the ‘Water Positive National Partner Network’, we have seen, first-hand, their willingness to listen to stakeholders and work with nontraditional allies to identify solutions,” said Peter Clark, President of Tampa Bay Watch. “Scotts is being responsive to Florida’s water quality issues as proven by their significant investment in research and restoration projects throughout the state.” The Scotts Miracle-Gro Company is passionate about helping people of all ages express themselves on their own piece of the Earth. With approximately $3 billion in sales, the Company is the world’s largest marketer of branded consumer products for lawn and garden care. The Company’s brands are the most recognized in the industry. In 2016, the Company ranked in Forbes 100 Most Reputable Companies in America for the second year in a row. To learn more about the Company and our initiatives, visit us at www.scottsmiraclegro.com
Raychoudhury T.,McGill University |
Naja G.,McGill University |
Naja G.,Everglades Foundation |
Ghoshal S.,McGill University
Journal of Contaminant Hydrology | Year: 2010
This study investigated the breakthrough patterns of carboxymethyl cellulose- and polyacrylic acid-stabilized zero-valent iron (Fe0) nanoparticles (NZVI) from packed sand columns under a range of pore water velocities of 0.02, 0.2 and 1 cm min- 1 and NZVI influent concentrations of 0.1, 0.5 and 3 g L- 1. The NZVI effluent relative concentrations of both types of particles decreased with slower flow velocities and increasing particle concentrations. PAA-NZVI exhibited slower elution from the columns than CMC-NZVI under identical experimental conditions, and this is attributed to more rapid aggregation kinetics of PAA-NZVI. The elution patterns of PAA-NZVI showed a stronger trend of gradually increasing effluent concentrations with flushing of additional pore volumes, especially at low flushing velocities and higher influent particle concentrations and this phenomenon too can be attributed to increasing aggregate sizes with time which caused decreases in the values of the single collector efficiency and thus the deposition rate constant. A 7 nm increase in CMC-NZVI aggregate size over 60 min was observed using nanoparticle tracking analysis. The reduction in colloidal stability due to aggregation of CMC- and PAA-NZVI was verified using sedimentation tests, and it was found that PAA-NZVI were less stable than CMC-NZVI. There were also notable inherent differences in the two NZVI particles. The CMC-NZVI were monodisperse with a mean diameter of 5.7 ± 0.9 nm, whereas PAA-NZVI had a bimodal particle size distribution with a small sub-population of particles with mean size of 30 ± 21 nm and a more abundant population of 4.6 ± 0.8 nm diameter particles. Furthermore, PAA-NZVI had a lower surface potential. These characteristics are also responsible for the different elution patterns CMC- and PAA-NZVI. © 2010 Elsevier B.V. All rights reserved.
Roach K.A.,University of Quebec at Trois - Rivieres |
Winemiller K.O.,University of Quebec at Trois - Rivieres |
Davis S.E.,Everglades Foundation
Freshwater Biology | Year: 2014
Summary: Comparative research and generalisations in lotic ecology are challenged by the dynamic hydrology of fluvial systems. The aim of this study was to understand more fully how factors such as light, nutrients and flow can predict variation in autochthonous production and algal biomass. We measured seasonal changes in percent bankfull discharge, inorganic nutrient concentrations, turbidity, instream primary production, respiration and algal biomass in the littoral zone of five floodplain rivers in one temperate and two tropical regions of the Western Hemisphere. The Brazos, Guadalupe and Neches rivers are in Texas, while the Tambopata River is in Peru and the Cinaruco River in Venezuela. Our study rivers represented a range of hydrological regimes, turbidity levels and nutrient concentrations. Flooding patterns were more seasonal in the tropical rivers than in the (temperate) Texas rivers. Inorganic nutrient concentrations were higher in the temperate rivers, probably due to anthropogenic nutrient loading. Turbidity was higher following periods of high flow in the Brazos, Tambopata and Guadalupe rivers than in the Neches and Cinaruco rivers. Littoral zones in the sediment-laden Brazos and Tambopata rivers became heterotrophic during periods of high discharge, while littoral zones in the Guadalupe, Neches and Cinaruco rivers were consistently autotrophic. Regression tree analysis suggested that algal production and biomass in the water column responded more strongly to seasonal changes in nutrients and temperature than to turbidity, while benthic algae responded more strongly to turbidity. Our findings suggest that during periods of high flow and turbidity in rivers containing fine sediments, autochthonous production is limited and terrestrial-based organic matter may assume greater importance in the aquatic food web. © 2014 John Wiley & Sons Ltd.
News Article | April 21, 2016
But now, seagrass is dying at a rate unseen since the late 1980s in the Florida Bay, off the southern tip of Florida between the Atlantic Ocean and the Gulf of Mexico. "It is like a desert," said fishing guide Xavier Figueredo, peering into the water, where only an occasional needle fish or ray could be seen scooting along a bottom clustered with matted, dead underwater grasses. Seagrass provides shelter for small fish, which are eaten by bigger fish, and serves as the foundation for the marine food chain. In Florida, where recreational saltwater fishing is a $7.6 billion industry, experts consider seagrass a key indicator of the ecosystem's health. "This has historically been a wonderful spotted seatrout fishery. This year it was non-existent, literally," said Figueredo, one of a group of fishing guides who cater to tourists visiting the string of islands known as the Florida Keys. Ecologists say the problem is mainly due to the way humans have for decades diverted the natural flow of fresh water from central Florida southward to the Everglades wetlands, protecting sugar cane farms and other property. A massive die-off that began in 1987 and lasted for years helped spark ambitious plans to protect the area, but fishermen say progress has been too slow. Now, they see the death cycle happening again, as increasingly warm and salty water smothers the underwater grass. First the grass detaches from the bottom. It floats to the surface during the day and sinks again at night, earning it the nickname "zombie grass," said Steve Davis, a wetland ecologist with the Everglades Foundation, as he inspected a once-popular fishing area called Whipray Basin. "It's dead, it just doesn't know it yet," he explained. Eventually, the grass bleaches, and the blades amass into smelly islands. The die-off makes an algae bloom quite likely, sucking oxygen out of the water and making it a hostile environment for marine life. "It is dramatic. It looks like a disaster area," said Davis. Heavy rain led to record freshwater inflows coming into the bay in January and February, Davis said, but it is not enough. The die-off is gathering steam. "We just have to now ride it out, and we know it is going to take years to recover," he said. State wildlife officials say the affected area covers about 25,000 acres (110,000 hectares) of dead sea grass—about the size of Paris. But Davis said fishermen who have seen it firsthand say it's twice that big—on the order of 50,000 acres. "It is a massive area in Florida Bay where the entire habitat has been decimated," said Davis. The crisis has prompted some fishing guides to press for government action. Some have formed advocacy groups like Captains for Clean Water, which has more than 9,000 followers on Facebook. The solution, they say, is to acquire a patch of land south of the state's largest freshwater lake, Lake Okeechobee, to act as a reservoir for fresh water that can flow south to the Everglades and the Florida Bay. But the land in that area belongs to sugar cane farms, a powerful industry known as "Big Sugar" that has resisted giving up any territory. "When times were tough, the industry was anxious to sell, and then times got better and the economics changed," Congressman Carlos Curbelo told a gathering of fishermen and concerned citizens in Islamorada this month. "We need to find a partner that is willing to engage." The lead government agencies involved—the US Department of the Interior and the South Florida Water Management District—did not respond to AFP requests for comment. The Everglades Foundation said money is not an issue, with some $200 million a year for the next 20 years earmarked to pay for the state's share of restoration, and federal funds to match. "The only other thing that is lacking is the political will to get the land that we need," said Davis. "Without that land, without that reservoir, we can't solve the problem in the Florida Bay." The Florida Bay did bounce back on its own after the 1987 die-off, but the rejuvenation process took nearly a decade. John Guastavino, who has been taking tourists out to fish from the Florida Keys for 26 years, remembers a time, not so long ago, when the catch was bountiful. "I've had days when I could go catch 65 redfish in a day, and days when I've caught 30 or 40 snook," he said. Now, "if you are having a good day, you might catch five or six snook," he added. "I can't remember the last time I had someone catch more than one or two redfish." He also has to travel farther than ever to find a good fishing spot. "It is probably one of the most frequently asked questions that I get," said Guastavino. "'Aren't there any fish back there, the 30 miles we just traveled?' It is sad to tell them, 'No, not really.'" Explore further: Restrictions on boaters proposed to protect Everglades seagrass