What is the Gulf of Mexico Dead Zone you ask? Well…it’s a layer of hypoxic water (low in dissolved oxygen) on the bottom of the Gulf of Mexico. It was first detected in the 1970’s but reached its peak in size in the 1990’s. The low levels of dissolved oxygen decrease the amount of marine life on the bottom of the Gulf within this zone, including many commercially valuable species supporting the Gulf seafood industry.
The red area indicates where dissolved oxygen levels are low.
What Causes this Dead Zone?
Drops in concentrations of dissolved oxygen within the water column can occur for a variety of reasons but is usually caused by one of two reasons. (1) Increasing water temperatures—as water temperature increases, its ability to hold dissolved oxygen decreases. (2) A process called eutrophication.
What is eutrophication?
Eutrophication is a process where an increase of nutrients in an aquatic system triggers an algal bloom of microscopic phytoplankton. These phytoplankton produce oxygen during the daylight hours but consume it in the evening. Once the bloom dies, decomposing bacteria begin to break them down and consume larger amounts of dissolved oxygen in doing so. When the dissolved oxygen concentrations drop below 2.0 mg/L we say the water is hypoxic and many marine organisms either begin to move out or die. The nutrients that trigger such blooms are primarily nitrates and phosphates. These can be introduced to the water column with plant and animal waste and with synthetically produced fertilizers we use on our fields and lawns. There is natural eutrophication, but when the process is triggered or accelerated by human activity we use the term cultural eutrophication.
So which is it; warming waters or eutrophication?
The Gulf of Mexico Dead Zone usually forms in spring and lasts through September. These are certainly the warmer months of the year, but the warmer waters are near the surface and much of the water column is not warm enough to cause this. Another point is that the Dead Zone is near Louisiana and there are warm locations in other parts of the Gulf where dead zones do not occur. However the Mississippi River does discharge near Louisiana. This river drains 41% of the continental United States, which contains 52% of the nation’s farms. The agricultural waste (plant, animal, and synthetic fertilizers) discharged into the Mississippi River contains nitrogen and phosphorus, the two key nutrients that trigger algal blooms. Based on this, most scientists agree that cultural eutrophication is the primary cause of the Gulf Dead Zone.
When they say it will be a “typical year”, what does that mean – what is a “typical year”?
Scientists from NOAA, the U.S. Geological Survey, and six partnering universities have released their annual forecast of the Dead Zone. The 2015 prediction has the area of the dead zone about equal to the size of Connecticut, which has been the average size for the past several years. This is what they mean by typical.
Can these dead zones occur in our area waters?
Yes, and they do. We do not typically call them “dead zones” but the same process occurs all over the world, including the bays of the Florida panhandle.
What can we do to reduce cultural eutrophication locally?
If you can do without fertilizing your lawn (or field), then do. If this is not an option then only put the amount of fertilizer required for your land/lawn. Most people over fertilize, which not only reduces water quality but is expensive for the property owners. If you can compost your plant waste, do so. With animal waste, please dispose of properly, in a manner where it not reach local waterways.
For more information on hypoxia, eutrophication, and solutions to reduce this problem, contact your county Extension office.
After the recent report of a fatality due to the Vibrio bacteria near Tampa many locals have become concerned about their safety when entering the Gulf of Mexico this time of year. So what are the risks and how do you protect yourself?
The rod-shaped bacterium known as Vibrio. Courtesy: Florida International University
What is the Flesh Eating Disease Vibrio?
Vibrio vulnificus is a salt-loving rod-shaped bacteria that is common in brackish waters. As with many bacteria, their numbers increase with increasing temperatures. Though the organism can be found year round they tend peak in July and August and remain elevated until temperature decline.
How do people contract Vibrio?
The most common methods of contact with Vibrio are entrance through open wounds exposed to seawater or marine animals and by consuming raw or undercooked shellfish, primarily oysters. The bacterium can also be contracted by eating food that is either served, and has made contact with, raw or undercooked shellfish or the juice of raw or undercooked shellfish.
What is the risk of serious health problems after contracting Vibrio?
Cases of Vibrio infection are rare and the risk of serious health problems is much higher for humans who are have a suppressed or compromised immune system, liver disease or blood disorders such as iron overload (hemochromatosis). Examples include HIV positive, in the process of cancer treatment, and studies show a particularly high risk for those with a chronic liver disease. The Center for Disease Control indicates that humans who are immunocompromised have an 80 times higher chance of serious health issues from Vibrio than healthy people. He also found that most cases involve males over the age of 40. According to the Center for Disease Control there were about 900 cases reported between 1988 and 2006; averaging around 50 cases each year. The Florida Department of Healthreported 32 cases of Vibrio infections within Florida in 2014 with 7 of these begin fatal. Five of the cases were in the Florida panhandle but none were fatal. So far this year in Florida there have been 11 cases statewide, 5 of those fatal. Only 1 case was in the panhandle and it was nonfatal. Though 43 cases and 12 fatalities over the last two years in Florida are reasons for concern, when compared to the number of humans who enter marine and brackish water systems every day across the state, the numbers are quite low.
What are the symptoms of Vibrio infection?
For healthy people who consume Vibrio containing shellfish symptoms could include vomiting, diarrhea, and abdominal pain. Wounds exposed to seawater that become infected will show redness and swelling. For the at-risk populations described above the bacteria will enter the bloodstream and rapidly cause fever and chills, decreased blood pressure, and blistering skin lesions. For these at-risk population 50% of the cases are fatal and death generally occurs within 48 hours.
It is important that anyone who believes they are at high risk and have the above symptoms that they seek medical attention as quickly as possible.
How can I protect myself from Vibrio infection?
We recommend anyone who has a chronic liver condition, hemochromatosis, or any other immune suppressing medical condition, not consume raw or undercooked filter-feeding shellfish and not enter the water if they have an open wound.
The Center of Disease Control recommends
If harvesting or purchasing uncooked shellfish do not consume any whose shells are already open
Keep all shellfish on ice and drain melted ice
If steaming, do so until the shell opens and then for 9 more minutes
If frying, do so for 10 minutes at 375°F
Avoid foods served, and has had contact with, raw or poorly cooked shellfish or that has had contact with raw shellfish juice
If shucking oysters at a fish house or restaurant, wear protective gloves
It is also important to know that the bacteria does NOT change the appearance or odor of the shellfish product, so you cannot tell by looking at them whether they are good or bad.
Following a previous article on the number of ways you can help sea turtles, this week we will look at ways that local residents can help keep our waterways clean. Poor water quality is a concern all over the country, and so it is locally as well. When we have heavy rain all sorts of products wash off into streams, rivers, bays, and bayous. The amount and impact of these products vary but most environmental scientists will agree that one of biggest problems is excessive nutrients.
Marine science students monitoring nutrient levels in a local waterway. Photo: Ed Bauer
Nutrient runoff comes in many forms. Most think of fertilizers we use on our lawns but it also includes grass clippings, leaf litter, and animal waste. These organic products contain nitrogen and phosphorus which, in excess, can trigger algal blooms in the bay. These algal blooms could contain toxic forms of microscopic plants that cause red tide but more often they are nontoxic and cause the water to become turbid (murky) which can reduce sunlight reaching the bottom, stressing seagrasses. When these algal blooms eventually die they are consumed by bacteria which require oxygen to complete the process. This can cause the dissolved oxygen concentrations to drop low enough to trigger fish kills. This process is called eutrophication. In addition to this, animal waste from birds and mammals contain fecal coliform bacteria. These bacteria are used as indicators of animal waste levels and can be high enough to require health advisories to be issued.
So what we can do about this?
We can start with landscaping with native plants to your area. Our barrier islands are xeric environments (desert-like). Most of our native plants can tolerate low levels of rain and high levels of salt spray. If used in your yard they will require less watering and fertilizing, which saves the homeowner money. It also reduces the amount of fertilizer that can reach the bay.
If you choose to use nonnative plants you should have your soil tested to determine which fertilizer, and how much, should be applied. You can have your soil tested at your county Extension Office for a small fee. Knowing your soil composition will ensure that the correct fertilizer, and the correct amount, will be used. Again, this reduces the amount reaching the bay and saving the home owner money.
Where ever water is discharged into the bay you can plant what is called a Living Shoreline. A Living Shoreline is a buffer of native marsh grasses that can consume the nutrients before they reach the bay and also reducing the amount of sediment that washes off as well, reducing the turbidity problem many of our seagrasses are facing.
These three practices will help reduce nutrient runoff. In addition to lowering the nutrient level in the bays it will also reduce the amount of freshwater that enters. Decrease salinity and increase turbidity may be the cause of the decline of several species once common here; such as scallops and horseshoe crabs. Florida Sea Grant is currently working with local volunteers to monitor terrapins, horseshoe crabs, and scallops in Escambia and Santa Rosa counties. We are also posting weekly water quality data on our website every weekend. You can find each week’s numbers at http://escambia.ifas.ufl.edu. If you have any questions about soil testing, landscaping, living shorelines, or wildlife monitoring contact Rick O’Connor at roc1@ufl.edu. Help us improve water quality in our local waters.
Attractive red berries entice homeowners to use as a landscape plant but coral ardisia can quickly dominate adjacent natural areas. photo courtesy of Les Harrison
Coral ardisia is also known as coral berry, spice berry, and scratchthroat. It was introduced into Florida in the early 1900’s for ornamental purposes.
In the ensuing years, it has since it escaped cultivation and has become established in hardwood hammocks and other moist woods of natural areas and grazing lands. Populations can currently found in Florida, Louisiana and Georgia.
This evergreen sub-shrub reaches a height of 1.5 to 6 feet and tends to grow in multi-stemmed clumps. Leaves are alternate, 8 inches long, dark green above, waxy, without hairs, and have scalloped margins and calluses in the margin notches. Flowers are typically pink to white in stalked axillary clusters, usually drooping below the foliage. The fruit is a bright red, globose, single-seeded berry, measuring approximately 0.25 inches in diameter. White-berried populations are also known to exist.
Coral ardisia is classified a Category I weed on the Florida Exotic Pest Plant Council Invasive Plant List. Control of coral ardisia may be accomplished by two methods. A low-volume foliar application of Garlon 4 or Remedy provides suppression of this plant. Complete foliar coverage is essential to success and re-treatment will be necessary for complete control. Basal bark applications with Garlon 4 or Remedy in an oil carrier can also be utilized for suppressing this invasive weed. Do not apply more than 8 quarts of Remedy or Garlon 4 per acre and treat no more than ten percent of the total grazed area if applying greater than two quarts per acre.
For local assistance, contact your county UF IFAS Extension office.
For more information contact Les Harrison, UF/IFAS Extension Wakulla County – Agriculture & Natural Resources Extension Agent by phone at 850-926-3931.
Will Sheftall Natural Resources Agent with UF/IFAS Extension Leon County exams the impacts of invasive coral ardisia on local urban forests in Northwest Florida.
Wild Hogs(Sus scrofa):
Wild Hogs, also called Feral Hogs, are not native to the U.S. Wild hogs are highly adaptable and can find suitable habitat easily. Wild hogs can be all shapes, sizes and colors since they are hybrids of many different breeds. Wild hogs sometimes resemble their domestic relatives but sometimes resemble their Eurasian backgrounds.
Wild hogs are probably the most prolific large mammals in the world. They reach sexual maturity at a young age. Females have multiple litters of 3-8 piglets per year. Natural mortality rates are low. Wild hog females and young live and travel in groups called sounders. Sounders typically have 1 to 3 adults and several young. When females reach maturity, they either stay with the sounder or they go out and form a new sounder with other young females. Young males leave the sounder alone at about 16 months.
Wild hogs are opportunistic omnivores that feed by rooting and grazing. This rooting behavior is why we consider them to be a pest. The impact of wild hogs on the environment is soil erosion, decreased water quality, spread of other invasive plants, damage to agricultural crops, and damage to native plants and animals. They have been documented as threats to threatened and endangered species. They can significantly impact populations of reptiles, amphibians, small mammals, ground nesting birds and even deer.
Wild hogs pose a health risk to humans because they can carry numerous diseases and parasites. Care should be taken when handling wild hogs. Wear gloves, cover any open wounds, and wear clothing that can be cleaned thoroughly.
Wild hog damage to pond bank. Photo by Jennifer Bearden
Human hunting is the most significant cause of mortality in wild hogs, although hunting alone will not control hog populations in a good habitat. The most effective way to remove wild hogs from a location is a combination of trapping and shooting.
In Florida, wild hogs may be hunted year round on private land (with permission of the landowner) and at night with no permit required. Hogs may be trapped year round. Wild hogs cannot be trapped and released onto public land. Trapped wild hogs can only be transported with a permit from FDACS) to slaughter or to an approved Feral Swine Holding Facility. For more information on Wild Hogs, go to: http://edis.ifas.ufl.edu/uw322 and http://www.myfwc.com/hunting/by-species/wild-hog/ .
Lawn care service providers applying fertilizer to Florida landscapes are now required to complete best management training. Photo credit: UF IFAS
Fertilizer becomes a problem in the environment when either too much is applied or it is used at the incorrect rate or wrong time. Rain or irrigation water can move these nutrients (remember, fertilizer is mostly composed of nitrogen, potassium, and phosphorus) off target, leaching them into the soil and groundwater or running off into surface waters.
Once in a creek, lake, river, or bay, this fertilizer intended to improve growth of turf or landscape plants instead fuels the growth of algae. In certain conditions this causes eutrophication, an overabundance of algae growth which gives water bodies a green, scum-covered appearance. As this plant material eventually breaks down, it uses up oxygen in the waters below, reducing the amount available for fish and other aquatic species. These scenarios can lead to fish kills and reduced water quality.
A body of water receiving excess nutrients can turn green and unhealthy from too much algae growth. Photo Credit: UF IFAS FFL program
The new legislation encourages professional lawn care staff to take a day-long course covering these concepts, and additional topics such as irrigation, pest management, and proper landscaping practices. The course, offered online and in every UF IFAS Extension office, prepares the audience for the test and certification, and gives useful tips and information for their everyday work.
Several counties, most recently Escambia, have passed local ordinances echoing the requirement to have this license when seeking a business tax certification to operate a lawn care service (providing fertilizer) in the county. In addition, local ordinances typically have a “prohibited application period,” which may involve a particular time of the year or weather condition. The ordinances also restrict blowing or sweeping lawn debris into storm drains, which can cause the same water quality problems as excess fertilizer. Visit the GI-BMP website to learn more about the program, and if you, friends, or neighbors use a professional lawn care service to fertilize your lawn, be sure to ask for proof of their fertilizer license.
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