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American Naturalist: The Rise and Fall of a Six‐Year Coral‐Fungal Epizootic by K. Kim, D. Harvell

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Am Nat 2004. Vol. 164, pp. S52–S63 © 2004 by The University of Chicago.

0003-0147/2004/1640S5-40257$15.00DOI: 10.1086/424609

Kiho Kim1,* and  C. Drew Harvell2,†

1. Department of Biology, American University, Washington, D.C. 20016‐8007;

2. Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853

Abstract:

Drivers of disease cycles are poorly understood in marine ecosystems in spite of increasing outbreaks. We monitored a newly emerged fungal epizootic (aspergillosis) affecting sea fan corals (Gorgonia ventalina L.) in the Florida Keys to evaluate causes of its rise and fall over 6 years. Since August 1997, aspergillosis has nearly eradicated large sea fans at some sites. However, sea fan densities have remained relatively constant due to episodic recruitment replacing large fans with small. Recruitment itself was affected by infection and occurred only when prevalence of disease was low. This impact on recruitment occurred because the largest, potentially most fecund colonies had the highest prevalence of disease, and the pathogen significantly suppressed reproduction of infected fans. Moreover, high mortality among adults resulted in a demographic shift to smaller colonies. The most dramatic impact of aspergillosis was the Keys‐wide loss of >50% of sea fan tissue from complete and partial mortality. Aspergillosis prevalence has declined steadily over the last 6 years, and we consider the following hypotheses for decline of the epizootic: change in environment, change in pathogen input, and increase in host resistance. We conclude that increasing host resistance is the most likely driver of the decline. However, a change in any of a number of factors, for example, recruitment of naïve hosts, rate of pathogen input, or environmental conditions (water quality and temperature), is likely to promote reemergence of the epizootic.

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Friends of the Everglades: An Evaluation of the Scientific Basis for “Restoring” Florida Bay by Increasing Freshwater Runoff from the Everglades by L. E. Brand

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http://www.everglades.org/articles/special-report-pg1.html

by Larry E. Brand, Rosenstiel School of Marine and Atmospheric Science,
University of Miami.
 
INTRODUCTION:
Florida Bay and the Florida Keys are at the downstream end of the Kissimmee River-Lake Okeechobee-Everglades watershed. Their ecological health depends on what happens upstream. Within the past 20 years, a number of ecological changes have occurred in South Florida coastal waters. In Florida Bay, large algal blooms have developed and persisted, large areas of seagrass and sponges have died off, and major changes have occurred in fish populations. In the Florida Keys, macroalgae have overgrown many coral reefs, coral diseases appear to be spreading, and many corals have died. Many of these changes are classical indicators of nutrient eutrophication.

The dominant hypothesis for explaining many of the changes, however, is that reduced water flow into Florida Bay from the Everglades led to hypersaline conditions, which then led to massive seagrass dieoff. This hypothesis further proposes that the seagrass dieoff and subsequent organic decomposition and sediment resuspension released nutrients which then generated the algal blooms. This hypothesis has been used as a rationale for pumping more fresh water into Florida Bay as part of a large scale alteration of water management in South Florida. The hypothesis is a reasonable one to begin with, but an examination of the data available leads to serious doubts about the validity of the hypothesis and the predicted ecological consequences of pumping more freshwater into Florida Bay.

CONCLUSIONS:

The dominant hypothesis for explaining many of the ecological changes that have occurred in Florida Bay in the past 2 decades is that reduced flow into Florida Bay from the Everglades led to hypersaline conditions, which then led to massive seagrass die-off. This hypothesis further proposes that the seagrass dieoff and subsequent organic decomposition and sediment resuspension released nutrients which then generated algal blooms. The data, however, show that hypersaline conditions cannot explain either the spatial or temporal distribution of seagrass dieoff in Florida Bay. Furthermore, seagrass dieoff cannot explain the spatial or temporal distribution of nutrients and algal blooms in Florida Bay.

It is hypothesized that the large algal blooms in Florida Bay are the result of nitrogen-rich waters in eastern Florida Bay meeting phosphorus-rich waters in western Florida Bay. Nutrient bioassays confirm that phosphorus is the limiting nutrient in the east and nitrogen is the limiting nutrient in the west, as predicted by the spatial distribution of N:P ratios.

It is hypothesized that much of the P comes from Miocene phosphorite deposits by way of Peace River erosion and subsequent coastal current transport along the southwest coast, and by way of groundwater through phosphorite-rich quartz sand deposits underneath certain areas of the coastal waters. It is argued that this P source has not changed significantly over the past few decades. It appears that much of the N comes from freshwater runoff from agricultural lands through the Everglades. It is argued that changes in water management practices in the past two decades have led to an increase in N inputs to eastern Florida Bay. Mixing of this water from the east with the P-rich water from the west has led to the large algal blooms that have developed in northcentral Florida Bay, altering the entire ecosystem. Some of this enriched water is transported to the middle and lower Florida Keys, where it may be adversely affecting the coral reefs and other oligotrophic ecosystems there.

In conclusion, it is hypothesized that if more freshwater from the Everglades-agricultural system is pumped into Florida Bay, as proposed (United States Army Corps of Engineers and South Florida Water Management District, 1999), the algal blooms will increase and the ecological problems of Florida Bay will get worse, not better. It is also hypothesized that if more passages along the Florida Keys between Florida Bay and the coral reefs are opened up, as proposed, the coral reefs will experience lower water quality.

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Marine Pollution Bulletin: Preliminary evidence for human fecal contamination in corals of the Florida Keys by E.K. Lipp, et. al.

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Erin K. LippCorresponding Author Contact Information, E-mail The Corresponding Author, a, Jennifer L. Jarrella, 1, Dale W. Griffina, 2, Jerzy Lukasikb, Jennifer Jacukiewicza and Joan B. Roseaa College of Marine Science, University of South Florida, 140, 7th Ave. S, St. Petersburg, FL 33701, USA

b Biosecure, 4641 W 6th St. Suite A, Gainesville, FL 32609, USA


Abstract

Corals and reef environments are under increased stress from anthropogenic activities, particularly those in the vicinity of heavily populated areas such as the Florida Keys. The potential adverse impacts of wastewater can affect both the environment and human health; however, because of the high decay rate of bacterial indicators in coral reef waters it has been difficult to document the presence of microbial contaminants and to assign risks in these environments. Here we show initial evidence that microorganisms associated with human feces are concentrated along the surface of coral heads relative to the overlying water column in the Florida Keys. Bacterial indicators (fecal coliform bacteria, enterococci or Clostridium perfringens) were detected in 66.7% of the coral surface microlayer (CSM) samples at levels between five and 1000 CFU/100 ml, but were found infrequently and at low numbers in the overlying water column (less-than-or-equals, slant2.5 CFU/100 ml). Similarly, enterovirus nucleic acid sequences, an indicator of human-specific waste, were detected in 93.3% of the CSM samples and only once in the water column by cell culture. Results show that coral mucus may accumulate enteric microorganisms in reef environments, and may indicate a risk to public and environmental health despite low indicator levels in the surrounding water.

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Water Research: Evidence for Groundwater and Surface Marine Water Contamination by Waste Disposal Wells in Florida Keys by J. Paul, J. Rose, et al.

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John H. Paula, Corresponding Author Contact Information, Joan B. Rose*a, Sunny C. Jianga, Xingting Zhoua, Pamela Cochrana, Christina Kellogga, Jordan B. Kanga, Dale Griffina, Samual Farrah*b and Jerzy Lukasikb
a University of South Florida, St Petersburg, FL 33701, U.S.A.
b University of Florida, Gainesville, FL, U.S.A.
 Water Research Volume 31, Issue 6, June 1997, Pages 1448-1454 

ABSTRACT

Injection wells (Class V disposal wells) are a major method for domestic wastewater disposal in coastal environments around Florida, and particularly the Florida keys, where there are nearly 700 in operation.

A recent report published in the June issue of Water Research by researchers at the University of South Florida indicates that wastewater disposed by these practices can rapidly contaminate groundwater and surface marine waters.

These investigators, led by Drs. John H. Paul and Joan B. Rose, used harmless bacterial viruses as a tracer for the movement of wastewater from a recently permitted class V disposal well in the Middle Keys.

This well meets current DEP requirements, which means that the well was drilled to 90 feet and cased with PCV pipe to 60 feet. Within 8 hours of addition of the tracer, it was detected in the groundwater, and within 36 hours it was detected in Florida Bay.

By 53 hours, the tracer appeared in a canal on the other side of US1, on its way to Hawk Channel and the Atlantic Ocean.

A second experiment performed last fall indicated that the tracer could move from the waste disposal well to the same canal in less than 8 hours, if strong North winds associated with a cold front occurred at the same time.

The meaning of these results is that wastewater from injection wells can rapidly make its way to the subsurface. This could cause potentially serious health problems for bathers in canals and coastal waters around the Florida Keys.

Disease causing microorganisms could be transmitted from wastewater to these waters where they could potentially infect bathers, windsurfers, jetski operators and other participants in recreational water-contact activities.

A second reason for concern is the transport of nutrients (inorganic and organic) into marine waters. These act like fertilizers which cause algal growth and water quality deterioration.

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University of North Carolina: Indo Pacific Reefs Disappearing More Rapidly Than Expected

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http://marine.unc.edu/announce_seminars/news/UNC%20Marine%20Research%20Garner%20Press%20Coverage/

Indo-Pacific Coral Reefs Disappearing more rapidly than expected. 

UNC News Release
8 p.m. ET, Tuesday, Aug. 7, 2007

Indo-Pacific coral reefs disappearing more rapidly than expected

CHAPEL HILL – Corals in the central and western Pacific ocean are dying faster than previously thought, University of North Carolina at Chapel Hill researchers have found. Nearly 600 square miles of reef have disappeared per year since the late 1960s, twice the rate of rainforest loss.

The reefs are disappearing at a rate of one percent per year, a decline that began decades earlier than expected, the researchers discovered. Historically, coral cover, a measure of reef health, hovered around 50 percent. Today, only about 2 percent of reefs in the Indo-Pacific have coral cover close to the historical baseline

“We have already lost half of the world’s reef-building corals,” said John Bruno, lead study author and associate professor of marine ecology and conservation in the department of marine sciences in UNC-Chapel Hill’s College of Arts and Sciences.

The results were published Aug. 8, 2007, in the online journal PLoS One. The study provides the first regional-scale and long-term analysis of coral loss in the region, where relatively little was known about patterns of reef loss.

The Indo-Pacific contains 75 percent of the world’s coral reefs and has the highest coral diversity in the world. High coral cover reefs in the Indo-Pacific ocean were common until a few decades ago, the researchers found.

Bruno and Elizabeth Selig, a graduate student in the College of Arts and Sciences’ curriculum in ecology, compiled and analyzed a database of 6,000 quantitative surveys performed between 1968 and 2004 of more than 2,600 Indo-Pacific coral reefs. The surveys tallied coral cover, a measure of the ocean floor area covered by living corals. Scientists rely on coral cover as a key indicator of reef habitat quality and quantity, similar to measuring an area covered by tree canopy as a gauge of tropical forest loss.

Coral cover declined from 40 percent in the early 1980s to approximately 20 percent by 2003, the researchers found. But for Bruno and Selig, one of the most surprising results was that coral cover was similar between reefs maintained by conservationists and unprotected reefs. This consistent pattern of decline across the entire Indo-Pacific indicates that coral loss is a global phenomenon, likely due in part to large-scale stressors such as climate change. But for Bruno and Selig, one of the most surprising results was that coral loss was just as extensive on some of regions most intensely managed reefs.

The results of the study have significant implications for policy makers and resource managers searching for ways to reverse coral loss. “We can do a far better job of developing technologies and implementing smart policies that will offset climate change,” Bruno said. “We can also work on mitigating the effects of other stressors to corals including nutrient pollution and destructive fishing practices.”

Although reefs cover less than one percent of the ocean globally, they play an integral role in coastal communities, Bruno said. They provide economic benefits through fisheries and tourism and serve invaluable services like buffering from storms. When corals die, these benefits quickly disappear. Coral disease, predators, rising ocean temperatures due to climate change, nutrient pollution, destructive fishing practices and sediment run-off from coastal development can all destroy reef communities.

“Indo-Pacific reefs have played an important economic and cultural role in the region for hundreds of years and their continued decline could mean the loss of millions of dollars in fisheries and tourism,It’s like when everything in the forest is gone except for little twigs,a few lone trees” Selig said.

The research was funded by a grant by the National Science Foundation and the Environmental Protection Agency’s Science to Achieve Results program.

Note: Bruno can be reached at (919) 360-7651 or jbruno@unc.edu. Selig can be reached at (919) 619-6797 or eselig@unc.edu.

UNC News Services contact: Becky Oskin, (919) 962-8596 or becky_oskin@unc.edu