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Editor’s Desk

Small Steps Make a Big Difference

Thirty-five years ago, when activists first focused on cleaning up Tampa Bay, all eyes were on the big polluters and they were easy to spot – and smell. As municipalities and industries have taken major steps to clean up their acts, however, an ever-larger percentage of pollution is coming from our homes, yards and automobiles.

This issue’s stories on low-impact development and fueling the future highlight the impact we have on the ecosystems around us – and how much we still need to accomplish. Most of us aren’t going to pack up and move into a green house this year or install a solar system to get off the grid, but there are dozens of things we can do to make a difference.

For instance, if every family in the country switched just one regular light bulb for a compact fluorescent, it would equal taking a million cars off the road in greenhouse gas reductions – plus save $600 million in energy costs every year. Or lower your thermostat by a degree this winter, save up to $40 and keep 250 pounds of carbon dioxide out of the atmosphere.

If you can’t dig a swale and berm in your backyard or put a garden on your roof, think rain barrel instead and capture stormwater for irrigation. Ongoing workshops at local extension services make it easy to purchase and install rain barrels.

And if you’re not planning to buy a hybrid car this year, check out these tips from the federal government that show how fast savings – and associated emissions – rack up:

While there are still many questions about the role human activity plays in what may or may not be increased and more intense outbreaks of red tide, there is no doubt that nutrients are the single most-important contaminant in Tampa Bay. If there’s even a small chance that we can make a difference in the utter devastation – from fish and dolphin to birds and manatees – caused by red tide, it needs to be considered.

–  Victoria Parsons

Good News, Bad News

Dear Editors,
Your publication is attractive, informative, and timely.  I particularly enjoy the diversity of the subject matter.

I found a small error in your Summer ’06 article, Tampa Bay Bucks Another Trend.  Walton Smith founded the University of Miami Marine Laboratory on the Coral Gables campus in 1943, which makes it 63 years old, not 43.


Jon C. Staiger Ph. D.

Are Humans Making Red Tide Worse? 

Larry Brand

One of the biggest questions facing researchers – and residents – is the role man-made nutrients play in red tide. Many scientists say that the data, collected somewhat haphazardly over the past 50 years, does not support a cause-and-effect relationship. Others, including the Sierra Club, argue that nutrients are fueling inshore red tides and that not limiting nutrients now will only make it harder to clean up when the science finally confirms the connection. Larry Brand, a marine biology professor at the University of Miami, wrote this column for Bay Soundings.

Blooms of Karenia brevis, the red tide algae, occur often along the southwest coast of Florida, and have done so for hundreds, probably thousands of years. In many areas of the world, red tides similar to the one in Florida (but different species) have been observed to be increasing. Some of the increases have been shown to be the result of increasing nutrients from land runoff.

Data collected over the past half-century along the southwest coast between Anna Maria Island and Sanibel Island were examined to determine if this was the case for the Florida red tide. The data analysis was restricted to the area with the highest density of data where routine sampling was undertaken to protect human health. Only data collected in 1954-1963 and 1994-2002 were used because of sparse and biased sampling in 1964-1993. A variety of techniques were used to reduce bias in the data used.

Red tide is much more abundant near the shoreline, where salinity is lower as a result of land runoff, than farther offshore. In both the 1954-1963 and 1994-2002 periods, average red tide concentrations were higher inshore than offshore, but cell concentrations were much higher in the 1994-2002 period than the 1954-1963 period. The overall increase in concentrations of red tide over the past 50 years was around 13- to 18-fold. The highest density that the red tide blooms achieved increased approximately 14-fold over the same time period.

The large increase in red tide abundance and highest achieved concentrations require an increase in nutrient availability. The higher concentrations of red tide along the shoreline where salinity is lower imply nutrient-rich water from land runoff. Published scientific data indeed indicate that significant nutrient enrichment has occurred in these coastal waters over the past 50 years.

We know of no natural sources of nutrients that have increased 13 to 18 fold. The most plausible hypothesis for the large increase in nutrients is the large increase in human activities. This would be expected to produce more sewage, more disturbance of terrestrial and wetland ecosystems and their ability to sequester nutrients, and more land surface runoff. There has also been a large increase in agriculture, fertilizer use, mining of phosphate deposits, and release of nitrogen-rich organic peat.

The factors that lead to the initiation of a red tide bloom are not well understood – nutrients may or may not be involved. Once a red tide bloom has developed however, higher concentrations of nutrients will allow the red tide to get larger. The large increase in both red tide abundance and nutrient input from human activities over the past 50 years, along with the much higher concentrations of red tide inshore, support the hypothesis that human-related nutrient inputs are leading to an increase in red tide abundance along the southwest coast of Florida.

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We welcome letters from readers on topics covered in Bay Soundings. The writer’s name, affiliation, address, and telephone number should be included and electronic submission is preferred. Letters may be edited to save space and ensure clarity. Send letters to editor@baysoundings.com.

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