Category Archives: coral reefs

MARINE ECOLOGY PROGRESS SERIES: Insecticides and a fungicide affect multiple coral life stages

Markey_et_al…2007

Mar Ecol Prog Ser
Vol. 330: 127–137, 2007 Published January 25

Kathryn L. Markey1, 2, Andrew H. Baird3, Craig Humphrey2, Andrew P. Negri2,*
1 School of Marine Biology and Aquaculture, and 3ARC Centre of Excellence for Reef Studies, James Cook University,
Townsville, Queensland 4811, Australia
2 Australian Institute of Marine Science, PMB
3, Townsville, Queensland 4810, Australia

ABSTRACT: Coral reefs are under threat from land-based agricultural pollutants on a global scale.
The vulnerability of early life stages of corals is of particular concern. Here, we compared the sensitivity
of gametes, larvae and adult branches of the broadcast-spawning coral Acropora millepora
(Ehrenberg) to a number of common pollutants, including 4 classes of insecticides—2 organophosphates
(chlorpyrifos, profenofos), an organochlorine (endosulfan), a carbamate (carbaryl) and a
pyrethroid (permethrin)—and a fungicide (2-methoxyethylmercuric chloride, MEMC). Fertilisation
of gametes was not affected by any of the insecticides at concentrations up to 30 μg l–1. In contrast,
settlement and metamorphosis were reduced by between 50 and 100% following 18 h exposure to
very low concentrations (0.3 to 1.0 μg l–1) of each insecticide class. The insecticides had few visible
effects on adult branches following 96 h exposure to a concentration of 10 μg l–1, with the exception
of profenofos, which caused polyp retraction, bleaching (i.e. algal symbiont densities were reduced)
and a slight reduction in photosynthetic efficiency of the algal symbionts. The fungicide MEMC
affected all life-history stages: both fertilisation and metamorphosis were inhibited at 1.0 μg l–1, and
polyps became withdrawn and photosynthetic efficiency was slightly reduced at 1.0 μg l–1. At 10 μg
l–1 MEMC, branches bleached and some host tissue died. This high susceptibility of coral larvae to
pesticides at concentrations around their detection limit highlights the critical need to assess toxicity
against all life-history stages of keystone organisms: to focus on mature individuals may underestimate
species sensitivity.

Common Dreams: ‘Inhospitable Oceans’ Acidifying at Rate Unseen in 250 Million Years (or Ever)

http://www.commondreams.org/headline/2013/08/26-0

Published on Monday, August 26, 2013
New study shows oceans in peril as acidification is happening at rate perhaps never seen in planet’s history
– Jon Queally, staff writer

ocean
(Photo: ‘Rough Ocean’/Flickr/Jacqueline Fasser)In both a new study published Monday and in a newspaper interview over the weekend, German marine biologist Hans Poertner warns the world that the crisis of ocean acidification—an intricately woven aspect of global warming and climate change—is now happening at a rate unparalleled in the life of the oceans for at least 250 million years and perhaps the fastest rate ever in the planet’s entire existence.

“The current rate of change is likely to be more than 10 times faster than it has been in any of the evolutionary crises in the earth’s history,” said Poertner in an interview with environmental journalist Fiona Harvey.

Ocean acidification—often called climate change’s “evil twin” by scientists and experts—happens as the pH level of seawater dwindles as it absorbs increasing amount of carbon dioxide (CO2) and though such fluctuations are a normally occurring phenomenon, when the balance tips too far, the acidification can imperil numerous types of marine life and is especially threatening to coral, shell fish, and other essential members of the ocean’s ecosystems.

Poertner—whose study, Inhospitable Oceans, was published Monday in the journal Nature Climate Change—says that if humanity’s industrial carbon emissions continue with a “business as usual” attitude, the problem of the oceans will be catastrophic.

To make comparisons, the study looked back at the ancient fossil record of the ocean to learn about what we can expect if the process continues unchecked. “The [effects observed] among invertebrates resembles those seen during the Permian Triassic extinctions 250m years ago, when carbon dioxide was also involved,” Poertner said. “The carbon dioxide range at which we see this sensitivity [to acidification] kicking in are the ones expected for the later part of this century and beyond.”

As Harvey explains:

Oceans are one of the biggest areas of focus for current climate change research. The gradual warming of the deep oceans, as warmer water from the surface circulates gradually to lower depths, is thought to be a significant factor in the earth’s climate. New science suggests that the absorption of heat by the oceans is probably one of the reasons that the observed warming in the last 15 years has been at a slightly slower pace than previously, and this is likely to form an important part of next month’s Intergovernmental Panel on Climate Change (IPCC) report.

The IPCC report, the first since 2007, will provide a comprehensive picture of our knowledge of climate change. It is expected to show that scientists are at least 95% certain that global warming is happening and caused by human activity, but that some uncertainties remain over the exact degree of the planet’s sensitivity to greenhouse gas increases.

And as Time points out in its review of the study:

Corals are likely to have the toughest time. The invertebrate species secretes calcium carbonate to make the rocky coastal reefs that form the basis of the most productive—and beautiful—ecosystems in the oceans. More acidic oceans will interfere with the ability of corals to form those reefs. Some coral have already shown the ability to adapt to lower pH levels, but combined with direct ocean warming—which can lead to coral bleaching, killing off whole reefs—many scientists believe that corals could become virtually extinct by the end of the century if we don’t reduce carbon emissions.

The Nature Climate Change study found that mollusks like oysters and squids will also struggle to adapt to acidification, though crustaceans like lobsters and crabs—which build lighter exoskeletons—seem likely to fare better. With fish it’s harder to know, though those species that live among coral reefs could be in trouble should the coral disappear. But ultimately, as the authors point out, “all considered groups are impacted negatively, albeit differently, even by moderate ocean acidification.” No one gets out untouched.

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ISME Journal via Coral-list: Bacterial profiling of White Plague Disease in a comparative coral species framework

The ISME Journal advance online publication 8 August 2013; doi: 10.1038/ismej.2013.127

Open–find complete paper with tables at:
http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej2013127a.html

Cornelia Roder1, Chatchanit Arif1, Till Bayer1, Manuel Aranda1, Camille Daniels1, Ahmed Shibl1, Suchana Chavanich2 and Christian R Voolstra1

1Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
2Department of Marine Science, Faculty of Science, Chulalongkorn University, Reef Biology Research Group, Bangkok, Thailand

Correspondence: CR Voolstra, Red Sea Research Center, King Abdullah University of Science and Technology, Building 2, Room 2226, Thuwal 23955, Saudi Arabia. E-mail: christian.voolstra@kaust.edu.sa

Received 23 January 2013; Revised 19 June 2013; Accepted 1 July 2013
Advance online publication 8 August 2013

Abstract

Coral reefs are threatened throughout the world. A major factor contributing to their decline is outbreaks and propagation of coral diseases. Due to the complexity of coral-associated microbe communities, little is understood in terms of disease agents, hosts and vectors. It is known that compromised health in corals is correlated with shifts in bacterial assemblages colonizing coral mucus and tissue. However, general disease patterns remain, to a large extent, ambiguous as comparative studies over species, regions, or diseases are scarce. Here, we compare bacterial assemblages of samples from healthy (HH) colonies and such displaying signs of White Plague Disease (WPD) of two different coral species (Pavona duerdeni and Porites lutea) from the same reef in Koh Tao, Thailand, using 16S rRNA gene microarrays. In line with other studies, we found an increase of bacterial diversity in diseased (DD) corals, and a higher abundance of taxa from the families that include known coral pathogens (Alteromonadaceae, Rhodobacteraceae, Vibrionaceae). In our comparative framework analysis, we found differences in microbial assemblages between coral species and coral health states. Notably, patterns of bacterial community structures from HH and DD corals were maintained over species boundaries. Moreover, microbes that differentiated the two coral species did not overlap with microbes that were indicative of HH and DD corals. This suggests that while corals harbor distinct species-specific microbial assemblages, disease-specific bacterial abundance patterns exist that are maintained over coral species boundaries.
Keywords:

16S rRNA gene microarray; Gulf of Thailand; Pavona duerdeni; Porites lutea; coral disease; White Plague Disease (WPD)

Special thanks to Coral-list

Why I am Still Opposed to Widening and Deepening Key West Harbor to Accommodate Larger Cruise Ships by DeeVon Quirolo

Points to consider in the discussion of whether to vote for a feasibility study to widen and deepen Key West harbor:

The science has been indisputable for a long long time on the negative impacts of siltation and dredging on or near coral reefs. Corals are living permanent structures on the ocean bottom comprised of colonies of living polyps that need clear, clean nutrient free waters to thrive. Dredging creates fine sediment and silt that covers corals, preventing photosynthesis and resulting in massive mortality, especially for Elkhorn and Staghorn corals–which cannot slough it off as can other corals. Such sedimentation also reduces the ability of all marinelife, including tarpon and other fish that utilize this area for habitat, to survive.

Episodic storm activity may stir up sediment but the wave action of those storms can also remove loose particulate matter from areas of the ocean bottom. While storm activities have historically affected visibility in the harbor and at the reefs, they do not compare in scale to the massive, chronic, intense effects of outright removal of habitat and the smothering of living formations by tons of dredge sediments that would occur immediately in the harbor and at nearby downstream coral reefs if additional widening and deepening of Key West Harbor were to occur.

It is incredulous to me that anyone associated with protecting coral reefs would dispute this elementary fact of coral ecology. In addition, the health of sea grasses and myriad other marinelife that depend upon this habitat would be severely impacted, including endangered sea turtles and dolphins.

The Key West Harbor Reconnaisance Report published November 2010 noted that the harbor is included in the “critical essential habitat” for both Elkhorn and Staghorn corals under the Endangered Species Listing for them. There has not been one case of allowing removal of critical essential habitat from the Jacksonville Corps of Engineers office in the last 15 years.

It states: “Under the Endangered Species Act (ESA) of 1973; the threatened coral Acropora cervicornis (staghorn coral) and Acropora palmata (elkhorn coral) could be located adjacent to the channel in the areas proposed for expansion as this area is designated as critical habitat for these species. While it is possible to relocate the actual colonies of coral, the critical habitat would be permanently removed. It is highly likely that the removal of several acres of occupied designated critical habitat (habitat where the species has been shown to be able to flourish under baseline conditions) could be considered an adverse modification of critical habitat under Section 7 of the ESA. This would be Jacksonville District’s first adverse modification of critical habitat determination in the last 15 years. It is also unknown what reasonable and prudent alternatives and measures National Marine Fisheries Service (NMFS) would include in a biological opinion to avoid the project adversely modifying designated critical habitat, as required under Section 7 of the Act.* It is expected that resource agencies would oppose any channel modifications outside the existing footprint.”

So this whole feasibility study could be a huge waste of money because there are good reasons why a permit would never be issued for the project thereafter. Surely we can find a more sustainable use of $5 million dollars—how about some stormwater treatment for the island of Key West to improve water quality?

The feasibility study is an effort to calculate the possibility of further widening and dredging in a harbor that was deepened just five years ago. Underneath Key West lies a fresh water aquifer. There are upwellings of fresh water in the harbor today. A massive deepening and widening may have severe unintended consequences on the aquifer, that at a minimum could result in salt water intrusion of that fresh water lens.

The last harbor dredging project just a few years ago included a mitigation plan by the Florida Keys National Marine Sanctuary to remove corals from the harbor with the purpose of restoring the damage. Despite their best efforts, there have been only a few of those corals planted in an offshore boat grounding site. For the most part, there has been no successful effort to restore the extent of coral colonies that existed in this area prior to the last dredging. It is therefore highly unlikely that another dredging project will succeed in restoring the habitat removed via mitigation this time either. It is just a false hope that the loss of biodiversity will be anything but an ecological disaster for this otherwise already stressed part of Key West’s coral reef ecosystem.

Often these dredge projects result in in-filling thereafter due to storm activity. Key West may be saddled with a harbor that produces chronic sedimentation without regular repeated environmentally destructive maintenance dredging. This will in turn affect the downstream coral reefs with additional chronic smothering contaminated sediment.

The greater question really is: How much more can the surrounding coral reef ecosystem of the Florida Keys handle in terms of human impacts? Isn’t it enough to have a thriving hotel, tourism and real estate industry? Can’t we draw a line in the sand and say “enough is enough”? Already the hoards of cruise ship visitors denigrates the downtown section to the exclusive benefit of a few businesses while high-end resorts and guesthouses hold their breath that this low-end massive impact to our quality of life will not repel their key markets. What about those who still hope that Key West can be a magic island home–don’t they deserve consideration?

Craig and I would encourage every voter in Key West to vote NO on the feasibility study to dredge Key West harbor….. again.

DeeVon Quirolo

WLOX: Scientists studying impact of oil spill on coral reefs

http://www.wlox.com/

Posted: Jul 05, 2013 6:41 PM EST Updated: Jul 05, 2013 7:02 PM EST
By Steve Phillips – bio | email

GULFPORT, MS (WLOX) – Scientists studying the impact of the Deepwater Horizon oil spill invited the media aboard their research vessels Friday morning during a stop at the Port of Gulfport. Much of their research has focused on the oil spill’s impact on coral reefs in the Gulf.

The scientists gave a tour of their working laboratories aboard the Nautilus and the Endeavor. One researcher says the area around the Deepwater Horizon site is probably the best surveyed section of sea floor in the world. Still, three years after the oil spill, they are just beginning to discover the extent of its impact. The research vessel Nautilus uses a pair of remote operated vehicles or ROVs to explore coral reefs in deep water all around the oil spill site in the Gulf.

“We’ve been going back and taking pictures of the same corals, leaving physical markers on the floor, visiting the exact same coral colonies again and again, every three to four months since the spill occurred,” said Dr. Erik Cordes, the chief scientist aboard. Early images showed definite damage to the corals near the Deepwater Horizon site. The follow-up study on the health of the coral continues with varying results. “The story is really mixed. Some of them seem to be doing better than they were three years ago. And a lot of them seem to be doing much worse,” said Dr. Cordes.

While the Nautilus team focuses on coral, scientists aboard its sister research ship Endeavor are busy looking at what happens with oil and gas as it moves through the water column from sea floor to sea surface. “We’ve been doing experiments to see what happens to oil when it falls to the sea floor, when it rises up and what happens when the carbon from the oil enters organisms and move through the food web,” said Dr. Joseph Montoya, a professor of geology at Georgia Tech University. Large devices on deck allow the team to collect both sea floor sediment and water samples from around the oil spill site.

“We are interested in both what’s happening to the oil that was released during the Deepwater Horizon incident and in understanding what happens to oil in general terms so that we’ll be prepared if this were ever to happen again,” said Dr. Montoya.

“There are so many unanswered questions still to pursue. We’ve I think come up with some answers on this cruise, but I think we’ve come up with a lot more questions,” Dr. Cordes admitted.

The research consortium includes scientists from 17 different universities. The project headquarters is at the University of Mississippi.