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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

[Coral-List] New Paper: Native Predators Do Not Control Lionfish by John Bruno

PLOS: goo.gl/rYfzx (http://t.co/GNmzGcCpNS)
July 12, 2013

We surveyed the abundance (density and biomass) of lionfish and native predatory fishes that could interact with lionfish (either through predation or competition) on 71 reefs in three biogeographic regions of the Caribbean. We found no relationship between the density or biomass of lionfish and that of native predators. Our results suggest that interactions with native predators do not influence the colonization or post-establishment population density of invasive lionfish on Caribbean reefs.

That does not mean native predators never eat lionfish. They probably do. But they don’t appear to measurably control lionfish populations. Furthermore, overfishing was not the cause (or a contributing factor) of the invasion. The “cause” was the introduction itself. Previous observations of reduced lionfish density within MPAs (e.g., Mumby et al 2011), which our results confirm, appear to be due to targeted culling by park managers rather than higher predator biomass.

John F Bruno, PhD
Professor
Department of Biology
UNC Chapel Hill
www.johnfbruno.com (http://www.johnfbruno.com)

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.

Marine Pollution Bulletin: Environmental impacts of dredging and other sediment disturbances on corals: a review by PL Erftemeijer, B Riegl, BW oeksema and PA Todd

http://www.ncbi.nlm.nih.gov/pubmed/22682583

Mar Pollut Bull. 2012 Sep;64(9):1737-65. doi: 10.1016/j.marpolbul.2012.05.008. Epub 2012 Jun 7.

This is another study available only for a price, but the abstract is instructive to the issue of how dredging harms corals. DV

Sinclair Knight Merz (SKM), P.O. Box H615, Perth, WA 6001, Australia. perftemeijer@globalskm.com
Abstract

A review of published literature on the sensitivity of corals to turbidity and sedimentation is presented, with an emphasis on the effects of dredging. The risks and severity of impact from dredging (and other sediment disturbances) on corals are primarily related to the intensity, duration and frequency of exposure to increased turbidity and sedimentation. The sensitivity of a coral reef to dredging impacts and its ability to recover depend on the antecedent ecological conditions of the reef, its resilience and the ambient conditions normally experienced. Effects of sediment stress have so far been investigated in 89 coral species (~10% of all known reef-building corals). Results of these investigations have provided a generic understanding of tolerance levels, response mechanisms, adaptations and threshold levels of corals to the effects of natural and anthropogenic sediment disturbances. Coral polyps undergo stress from high suspended-sediment concentrations and the subsequent effects on light attenuation which affect their algal symbionts. Minimum light requirements of corals range from <1% to as much as 60% of surface irradiance. Reported tolerance limits of coral reef systems for chronic suspended-sediment concentrations range from <10 mg L(-1) in pristine offshore reef areas to >100 mg L(-1) in marginal nearshore reefs. Some individual coral species can tolerate short-term exposure (days) to suspended-sediment concentrations as high as 1000 mg L(-1) while others show mortality after exposure (weeks) to concentrations as low as 30 mg L(-1). The duration that corals can survive high turbidities ranges from several days (sensitive species) to at least 5-6 weeks (tolerant species). Increased sedimentation can cause smothering and burial of coral polyps, shading, tissue necrosis and population explosions of bacteria in coral mucus. Fine sediments tend to have greater effects on corals than coarse sediments. Turbidity and sedimentation also reduce the recruitment, survival and settlement of coral larvae. Maximum sedimentation rates that can be tolerated by different corals range from <10 mg cm(-2) d(-1) to >400 mg cm(-2) d(-1). The durations that corals can survive high sedimentation rates range from <24 h for sensitive species to a few weeks (>4 weeks of high sedimentation or >14 days complete burial) for very tolerant species. Hypotheses to explain substantial differences in sensitivity between different coral species include the growth form of coral colonies and the size of the coral polyp or calyx. The validity of these hypotheses was tested on the basis of 77 published studies on the effects of turbidity and sedimentation on 89 coral species. The results of this analysis reveal a significant relationship of coral sensitivity to turbidity and sedimentation with growth form, but not with calyx size. Some of the variation in sensitivities reported in the literature may have been caused by differences in the type and particle size of sediments applied in experiments. The ability of many corals (in varying degrees) to actively reject sediment through polyp inflation, mucus production, ciliary and tentacular action (at considerable energetic cost), as well as intraspecific morphological variation and the mobility of free-living mushroom corals, further contribute to the observed differences. Given the wide range of sensitivity levels among coral species and in baseline water quality conditions among reefs, meaningful criteria to limit the extent and turbidity of dredging plumes and their effects on corals will always require site-specific evaluations, taking into account the species assemblage present at the site and the natural variability of local background turbidity and sedimentation.