Need Another Reason to Conserve Mangrove Habitats? Think about Your Economy.

Mangroves are a very important ecosystem, and yet they are one of the most threatened and fastest disappearing. Since 1980, between 20 and 35% of mangrove area has been cleared, largely to accommodate coastal development and aquaculture.1 As seen in Figure 1, aquaculture requires vast expanses of space, and this space is often acquired through the destruction of mangroves. Aquaculture alone is responsible for 52% of mangrove habitat loss annually.2 Hopefully these numbers alarm you, as I have demonstrated in my two previous blog postings why mangroves are important to conservation of coral reef ecosystems. The main reasons I provided were that mangroves serve as an important nursery for many reef species and that one specific herbivore, the rainbow parrotfish, was functionally dependent on mangroves, and that loss of this fish would have considerable effects on rates on algal grazing on reefs. Clearly, mangrove conservation is a very effective way to help improve coral reef health.

Figure 1. Aquaculture ponds where a mangrove forest once stood in Borneo. (Source: https://news.mongabay.com/2015/09/new-study-exposes-true-costs-of-converting-mangroves-in-southeast-asia/)

However, for many people, as well as many governments, a negative monetary effect of habitat loss is a much more effective call to action compared to implications for connected ecosystems. For this reason, in this final blog post I am going to focus on the roles of mangrove ecosystems that have direct impacts on human populations, as well as their economic value.

Mangroves serve many functions that directly affect human populations. They are especially important because a disproportionate amount of people live in coastal environments: while they account for only 2% of the world’s land area, coastal regions contain 10% of the world’s population.3 Coastal populations are especially vulnerable to climate change and coastal hazards, such as tsunamis, hurricanes, and cyclones. Mangroves can reduce wave energy of coastal hazards, and reduce the height of storm surges.3 In past cyclones, areas protected with mangroves suffered from less loss of human lives and less damage to property, livestock, and other economically important assets.2 The advantages of mitigating the effects of cyclones can not be understated, as the destruction they cause can be enormous and very expensive to clean up, as evidenced by Figure 2.

Figure 2. Devastation as a result of a cyclone in Fiji. Communities protected by mangroves have been show to feature less destruction from cyclones. (Source: http://www.publicfinanceinternational.org/news/2016/02/fiji-appeals-funds-after-destruction-caused-cyclone)

Another way coastal communities are threatened is by land loss, as a result of both rising sea levels and erosion. Mangroves can increase sedimentation and reduce erosion and movement of the sediments.3 This is a result of their complex, dense root structure. Healthy coastal ecosystems have proven to be more effective at protecting shorelines than man-made structures. Another advantage mangroves may have over engineered structures is that they may be able to respond to rising sea levels by increasing in elevation and growing to keep up with the rising seas.3

Mangroves also store a considerable amount of carbon. It has been estimated that mangrove habitats worldwide store 20 Pg of carbon, which is roughly equivalent to 2.5 times annual global carbon dioxide emissions. Additionally, if these ecosystems can persist undisturbed, the amount of carbon stored in mangroves will increase as a result of biological sequestration and carbon burial.4 A practice that has grown in popularity in recent years is for companies or countries to make an effort to offset their carbon dioxide emissions (in addition to making efforts to reduce them). This has included measures such as funding the installation of wind turbines replanting trees in rainforest habitats. Preventing mangrove loss is another viable way to offset carbon emissions, and it is relatively inexpensive economically. Preventing mangrove loss has an estimated cost of roughly $4 to $10 ton-1 CO2.4 Not only is this a cost effective method to offset emissions, it also has many other benefits as it benefits a very vital ecosystem.

Mangroves can have important roles in economies, especially in island communities. Mangroves are a source of both timber and food, and they greatly increase yields for many commercial fishing populatioins. It is estimated that the composite economic value of mangroves in Pacific islands is between $4,300 and $8,500 ha-1 yr-1.1

Although I hope that everyone would care about the health of the ocean, and coral reefs specifically, doing so is not necessary to understand that mangroves are an ecosystem worth preserving. It is obvious that further loss of these habitats should be stopped based on their impact on communities and local economies alone.

Figure 3. A community woks to replant a mangrove forest. Doing so can have many positive effects.(Source: https://evelynanderson.wordpress.com/creativity-action-and-service )

Ultimately, it is not the motivation behind conservation that is important, but rather the action that is taken. Many coastal communities have made efforts to preserve mangrove habitats. As shown in Figure 3, many groups have also done work to replant mangroves lost either from storm or previous removal. Vietnam, a country that is especially threatened by rising sea level, has lost over half of its mangroves. However, the government has begun a program to replant them. The Vietnamese Minister of the Environment believes Vietnam has a small chance to mitigate climate change by replanting the mangroves due to their roles in coastline protection and in absorbing carbon dioxide.Hopefully these replanting efforts will not only preserve Vietnam’s coast, but also benefit the coral reefs located nearby.

Sources

1.  Atkinson, S. C. et al. “Prioritizing Mangrove Ecosystem Services Results in Spatially Variable Management Priorities.” PLoS ONE, vol. 11, no. 3, 2016, e0151992.

2. Barber, E. B. et al. “The value of estuarine and coastal ecosystem services.” Ecological Monographs, vol. 81, no. 2, 2011, pp. 169-193.

3. Spalding, M. D. et al. “The role of ecosystems in coastal protection: Adapting to climate change and coastal hazards.” Ocean & Coastal Management, vol. 90, 2014, pp. 50-57.

4. Siikamaki, J., Sanchirico, J. N., Jardine, S. L. “Global economic potential for reducing carbon dioxide emissions from mangrove loss.” Proceedings of the National Academy of Sciences of the United State of America, vol. 108, no. 36, 2012, pp. 14369-14374.

5. Ramos, S. A.”Due To Rising Sea Levels, Vietnam Is In Danger Of Sinking.” Travelers Today, 19 April 2017.

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A biological House of Cards

Why estimate biodiversity? Why do we even care? The total biodiversity can be used to represent the total amount of information we can learn. The gap between the number of species currently known and the estimated total number of species signifies a gap in our knowledge base for ecosystems and the entire global system. And for researchers this can determine something even more important: funding. Money runs the world and the world of academics is no different. Research cannot be conducted without the necessary funds. Funds are typically rewarded to projects deemed impactful. For taxonomic research and discovery based research this could include research that rewards the greatest amount of discovery for the least effort exerted. Other research which fills in a specific gap in the understanding of ecological relationships can also be considered impactful.

Right now the question researchers still attempt to address is just how large this gap is. How many species are there really? How many species will researchers conceivably be able to find and describe? And since we cannot truly say how many species there are, how close of a guess can we make?

Figure 1. Estimation of total marine and terrestrial species using strategy of higher taxonomy. Mora, et al.1

 

 

 

 

 

 

Estimates are constantly being offered by scientists. Many use different strategies such as the use of higher taxonomic groups to estimate the total number of species (Figure 1, above). One such estimate from 2011 suggests a total global diversity of 8.7 million (± 1.3 mil) eukaryotic species. Of which, 2.2 million are predicted to be marine species1. Every estimate given includes a margin of error to account for the uncertainty. Another article estimated there to only between 0.7 and 1 million marine species2. Quite obviously, scientists have not yet agreed on an estimate of diversity.

As of 2012, 226,000~ marine species have been described, another 72,000~ have bee discovered, but not yet described2. So with different estimates, there is anywhere from 50-90% of marine species left to be discovered. This is a very large range. As species continue to be discovered, the data used to make these calculations becomes more comprehensive and will increase the power of the extrapolations that can be made. Further challenges include the breadth of knowledge required to recognize a new species, the wide geographic range, and accessibility.

Figure 2. House of cards metaphor. pc. Meghana Kulkami

Beyond estimations – why is biodiversity a concern? The distribution of biodiversity can help focus conservation efforts. It has been suggested that higher biodiversity is associated with stronger resilience. This is understandable as a greater number of species offers more opportunities for functional roles to be filled and at times be filled by more than one species. Maintaining biodiversity may be an important key to limiting impacts of invasive species, anthropogenic climate change, and other environmental stressors. In this way ecosystems with high biodiversity effectively function as a biological “house of cards”, allowing a single species to be removed without losing the entire ecological structure3 (Figure 2, above).

1Mora, et al. (2011) How Many Species Are There on Earth and in the Ocean? Plos biology. 9: 1-8

2Appeltans, W. et al. (2012) The Magnitude of Global Marine Species Diversity. Current Biology. 22: 2189-2202

3https://www.e-education.psu.edu/geog030/node/398

 

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Sponges and Christmas Tree Worms and Corals, Oh My!

We’ve arrived at the last installment of my blog series on colors and coral reefs! I’ve talked about coral pigmentation in relation to coral bleaching and coral reef fish colors, also in relation to coral bleaching.

In this post, I’m going to talk about two more colorful reef organisms: sponges and Christmas tree worms (Spirobranchus giganteus). First, I’ll discuss a study published in 1995 that looked to understand, among other things, the ecological significance of sponge colors. Then, I’ll discuss a study that highlighted a positive relationship between Christmas tree worms and Porites coral colonies.

Sponges are important, and colorful, components of coral reef ecosystems. Sponges are filter feeders, sucking up organic matter release by corals and other planktonic life1. Sponges are thus responsible for recycling organic matter and nutrients on reefs, which is especially important considering that reefs thrive in nutrient poor waters2. Sponges are susceptible to predation, and scientists have investigated possible protections against or responses to the threat of predation.

A study by Joseph Pawlik et al. investigated sponges in the Caribbean and their deterrent responses to predatory reef fish. The researchers looked for and, surprisingly, did not find any relationship between sponge color and deterrency3. One might expect that the bright colors characteristic of some sponges serve as warning coloration, but results indicated otherwise.

In the genus Agelas, one species (Agelas clathrodes) that is brightly colored red or orange was observed in addition to five other species that are all brown or black and belong to the same genus. All six species were deterrent to the same extent3. These results are shown in Figure 1 below, highlighted in the yellow box. This result indicates that these sponges are not aposematic. Aposematic is just a fancy word for when coloration or markings serve to warn or repel predators. Other hypotheses for the ecological significance of these sponge’s coloration must be tested.

Fig 1. This graph shows the number of sponge-infused pellets eaten by the Bluehead wrasse (Thalassoma bifasciatum) for various species of sponge (along the x-axis). The pellets each contained organic extracts from the sponges at natural concentrations. Notably, in the Agelasidae genus (yellow box) there was no significant difference in predation despite variation in coloration. Graph modified from Pawlik et al.3

The Christmas tree worm (seen in the photo below), resembles a small, decorated spruce tree, and is a notable bio-eroder of coral reefs. It is a polychaete worm, which means it’s in a class of worms generally found in marine environments4.

Fig 2. A “forest” of colorful Christmas tree worms on a coral. They are part of the group polychaetes, which includes worms mostly found in the ocean4. There are many color morphs of Spirobranchus gigantea and not all are known or described. Photo by Nick Hobgood.

These colorful creatures might be more helpful to coral colonies than previously thought, especially coral in the Porites genus. A study done by DeVantier et al. showed that coral colonies in the Porites genus and Christmas tree worms engaged in a mutualistic symbiosis5. A symbiosis is just the interaction between two different organisms that live in close proximity to each other. Mutualistic symbiosis occurs when two organisms live together, depend on each other and both benefit from the interaction. In this case, Porites coral colonies provide protection for the worms and a location for the worms’ suspension feeding. The Christmas tree worms protect the coral from predation by the Crown of Thorns Starfish (Acanthaster planci)5.

In this study, the researchers first established the possibility of a mutualism by recording observational data. A table included below, shows visual census data of partially and totally consumed Porites colonies. There is a strong correlation between the presence of Spirobranchus gigantea, the Christmas tree worm, and living Porites colonies.

Fig 3. Visual census data of Porites colonies that are either partially consumed or totally consumed. The colonies that were totally consumed had no Christmas tree worms. The partially consumed colonies (or those that had living coral polyps) had lots of Christmas tree worms. This suggests that the worms protect the Porites to some extent from predation threats. Table from DeVantier et al.5.

The authors discuss how they believe the Christmas tree worm deters Crown of Thorn Starfish predation. They think that the worms irritate the starfish’s tube feet or stomach and this irritation drives the predator away from the Porites colonies5. So, Christmas tree worms aren’t just pretty decorations! The colorful little worms have a role in protecting reef species against pesky predators.

Thanks for reading my blog posts! I hope you’ve learned about coral reef ecosystems and their spectacularly colorful inhabitants. We all need to appreciate the complexity and beauty that characterize coral reef ecosystems and prioritize their continued existence and health. It is more important than ever to take action to protect reef ecosystems. Sponges and worms, although colorful and thus more noticeable, are not the only coral reef ecosystem inhabitants that are affected by coral bleaching, which can have cascading effects throughout an entire ecosystem. In order to protect coral reefs and coral reef organisms, we need to try to understand and then protect colorful and ‘bland’ species alike.

 

References:

1 Morgan, James. “Sponges Help Coral Reefs Thrive in Ocean Deserts.” BBC News. BBC. 07 Oct. 2013. Web. 19 Apr. 2017. http://www.bbc.com/news/science-environment-24398394.

Sheppard, Charles R.C. et al. “The Biology of Coral Reefs.” Oxford University Press. 2012. Print.

3Pawlik, Joseph R., et al. “Defenses of Caribbean Sponges against Predatory Reef Fish. I. Chemical Deterrency.” Marine Ecology Progress Series, vol. 127, no. 1/3, 1995, pp. 183–194., www.jstor.org/stable/24855132.

Frost, Emily. “The Christmas Tree Worm, Decorating Coral Reefs Year-Round.” Smithsonian.com. Smithsonian Institution, 14 Dec. 2012. Web. 19 Apr. 2017. http://www.smithsonianmag.com/science-nature/the-christmas-tree-worm-decorating-coral-reefs-year-round-161933735/.

DeVantier, L.M. et al. “Does Spirobranchus giganteus protect host Porites from predation by Acanthaster planci: predator pressure as a mechanism of coevolution?” Marine Ecology Progress Series, vol. 32. 1986. Pp. 307-310. http://www.int-res.com/articles/meps/32/m032p307.pdf?pagewanted=all

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This Fish is No Damsel in Distress

You may be used to hearing about damsels in distress but, as you’ll see, damselfish do not necessarily fit this cliché. To give a little background, damselfish are herbivorous fish that have actually been known to be a key beneficial component of their native reef ecosystem. Damselfish, shown in Figure 1, originate from the Indo-Pacific region and have recently been introduced into the Gulf of Mexico possibly through aquarium releases and ballast water.1 Now, this can be troublesome because damselfish are not native to the Gulf of Mexico region. The damselfish could potentially be a cause distress. But how do we know if the damselfish is likely to become a dangerous invasive species? Well, let’s take a look.

Figure 1. Image of young yellowtail damselfish. Flickr2

The damselfish seems to have limited dispersal in the Gulf of Mexico area, which may be a good sign. According to a study conducted by Robertson et al., the damselfish have, so far, only spread to the southwest Gulf of Mexico and do not seem to be present in the northwest Gulf of Mexico or Southeast Florida.1 Although the damselfish may have only spread to the southwest Gulf of Mexico, they have established a self-sustaining population on reefs near Veracruz, and it is not the presence that is most concerning, but the fact that the population is self-sustaining that is of highest concern (Figure 2).3 This means that the population is successful at reproducing and has managed to thrive in conditions it is not native to, without the aid of any other species; it has acclimated to this new environment pretty well.

Figure 2. Map of the Gulf of Mexico region. The boxed off section near Veracruz is then blown up on a larger scale in the box located on the upper right corner. The box in the upper right corner shows locations infected with established damselfish populations, represented by black dots. It also shows simulation sites from Johnston and Akins’ simulation experiment, represented by grey squares. Marine Biology3

What does this mean for the coral reefs of the Veracruz region and how will the native fish be affected? Well, although the lionfish and damselfish share similar native habitats, they do not necessarily have the same effect on the habitats they have invaded. As I mentioned in my earlier post, lionfish played a large role in causing the decline in the native fish biomass of the US Atlantic coast by predating on the native fish. The damselfish do not have such a dramatic impact on the regions they have successfully populated. But, with the introduction of a new species, the reef make-up is bound to change in some sort of way. While the damselfish may not be predators like the lionfish, they are competing with native fish for habitat.3 Potential expansion of the damselfish population in the Gulf of Mexico could therefore be harmful to the native reefs. A simulation conducted by Johnston and Akins shows that in 5 years, the Veracruz reefs will face increased invasion pressure from damselfish, and this can be seen in Figure 3.3 The likelihood of the expansion of the non-native damselfish is high enough for us to be concerned.

Figure 3. Map of Gulf of Mexico, showing simulated settling locations of larvae over a period of 5 years. Year 1 represented by blue, year 2 represented by green, year 3 represented by yellow, year 4 represented by orange, and year 5 represented by red. Marine Biology3

Further research on the damselfish population in the Gulf of Mexico could help us gain a better understanding of the impacts of the non-native damselfish on the Atlantic reefs. Assessing the mode of introduction, population monitoring, and observing ecological interactions with native fish could be points of focus for further studies on the non-native damselfish in the Gulf of Mexico.1 It may be easy to overlook the risk involved with established non-native fish populations, especially when we are viewing these populations in their early stages of expansion – a mistake we made with the invasive lionfish.3 For this reason, it is imperative to pay close attention to non-native fish populations and anticipate the potential damage they can do to native habitats.3 Management strategies should be implemented earlier rather than later, in order to prevent extreme damage. We should be keeping an eye on this damsel, who knows if we have an invader on our hands? An invasive species does not have to be an “apex predator” to have a negative impact on a reef, even a fish as small as the damselfish can disrupt the balance of the reef ecosystem by taking on the role of a new competitor.4 Even though the damselfish may not be considered invasive yet, since its population numbers are not large enough, it does have the potential of becoming an invasive species in the Gulf of Mexico.

According to Johnston, the damselfish is “just one of at least 40 marine aquarium fish that have been documented in the tropical Atlantic”.4 We, as humans, have had a large impact on the introduction of these 40 different new species. Introduction of invasive species through aquarium trade is only one example. With this last blogpost, I want to remind you to pay attention to things that are going on around you. Acknowledging the influence humans have on the habitats surrounding us, especially marine habitats that we do not get to see on a daily basis, is one step towards preserving our beautiful oceans and reefs. Take action and stay involved, whether that be through directly getting involved in conservation or just by reading a few blogposts about invasive species. Ignorance is not bliss, and now is the time to take action and rectify the damage that has been done to reef ecosystems worldwide.

 

Resources:

1Robertson, D. Ross, et al. “An Indo-Pacific damselfish well established in the southern Gulf of Mexico: prospects for a wider, adverse invasion.” Journal of the Ocean Science Foundation 19 (2016): 1-17.

2DoctorJB. “Juvenile Yellowtail Damselfish.” Flickr. Yahoo!, 05 Feb. 2008. Web. 19 Apr. 2017. <https://www.flickr.com/photos/doctorjb/2243490200/in/photolist-4qfttw-8uBcAk-4bn3R7-stuW8c-6o6dtj-cVriHG-dT2zd8-kBmTVK-qwYf1J-k7JoaJ-8wvXHT-4WGdJq-6pEqVL-3Qb2Ep-jhseKD-f3en2U-5SGUny-77iiYM-6QaNtP-77nf4S-aJNyjB-2pGtGv-c81gGo-dLjSyo-9G9cRp-dTMe15-9Gc7WN-ehgGMi-7wbv4S-56GDJE-75hpjq-5TjbnW-7oPjpd-p7UxQs-9BzveJ-aFbM43-83UuXF-bfYPzZ-drjz7d-JYEm2-bCDBnz-6yjkeh-7VRzPh-n3GkAZ-fnXAy7-nUh2ef-5T3DPQ-fn4nQc-bnyAxH-SXrK4b/>.

3Johnston, Matthew W., and John L. Akins. “The non-native royal damsel (Neopomacentrus cyanomos) in the southern Gulf of Mexico: An invasion risk?.” Marine biology 163.1 (2016): 12.

4Nova Southeastern University. “Potential invasive species identified in S. Gulf of Mexico: Research shows non-native damselfish in part of Gulf.” ScienceDaily. ScienceDaily, 19 January 2016. <www.sciencedaily.com/releases/2016/01/160119141800.htm>.

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How we can create 3,200 coral reefs in the Gulf of Mexico

In my last post, I discussed a deeply worrying situation that unfolded last year in the East Flower Garden Banks. Thankfully, last year’s bleaching event appears to have been resolved, and the reef is now in recovery. Scientists looking to survey the extent of the damage looked not only at the East Banks, but also in the surrounding areas for any evidence that the bleaching had been spreading. One detail that really caught my attention was that these researchers checked both the West and Stetson Banks, but also on the legs of oil platforms in the area. This got me thinking: are corals often found growing on the legs of oil platforms? As the state of coral reefs around the world continues to worsen from year to year, conservation biologists are exploring a variety of different ways we might be able to reverse this negative trend. One of these solutions involves building artificial reefs: laying man-made reef framework down and then transplanting corals, bypassing the very slow process by which this would naturally occur. The focus of this blog post will be on how the numerous oil platforms scattered across the Gulf of Mexico might play a role in conserving and expanding corals in that region.

US Gulf of Mexico Oil and Gas Platforms, by Rob Shell. Note how there is already a vast amount of groundwork laid out, just waiting for coral transplantation. (Flickr Creative Commons)

One of the great challenges to coral reef conservation efforts is in funding and manpower. It’s hard to find the space in already limited ecological conservation budgets to implement the reef-saving solutions scientists are proposing. I haven’t heard very much discussion so far that touches on using infrastructure that has already been laid down rather than building up artificial reefs from scratch. There are currently 3,200 oil platforms in the Northern Gulf of Mexico1, with more on the way. These platforms are visualized in the image above. These platforms, firmly anchored down to the seafloor, theoretically provide the perfect antecedent topography that reefs require to initially begin growing. The legs of these oil platforms also span the full length of the zone normally habitable by corals. No money would need to be spent laying anything in place on a large scale, because that work has already been done. This would cut down on costs tremendously. Cooperating with artificial reef building efforts would also provide energy companies with opportunities to show that they are playing their part in improving the environment.

A study by the US Ocean Energy analyzed in depth the different kinds of coral species found on 13 different oil platforms in an elliptical shape around the Flower Garden Banks. The coral species that were observed growing on these platforms are many of the same ones that can be observed at the banks, including Madracis Decactis and Pseudodiploria strigosa1. This indicates that coral larvae from the Flower Garden Banks are carried along ocean currents to ultimately settle on oil platforms. There was a strong correlation between the age of a platform, and the density of coral growth that could be observed there1. This study took mere observation of coral settlement on oil platforms a step further by mounting artificial terra cotta growth racks on the platform legs and observing the rate of natural coral settlement over time. Corals grew very slow on these racks- much slower than even natural processes, likely due to the distance from the Flower Garden Banks1. This makes sense, and therefore these results should not be discouraging. I would like to see a follow-up study where pieces of already developed coral are transplanted onto oil platform legs and then monitored over time.

Strawberry Anemones, by Michael Ziegler. This colorful growth is just one example of how oil platforms can serve as a base for coral growth in the Gulf of Mexico. (Flickr Creative Commons)

If utilizing preexisting oil platforms in the Gulf of Mexico and other parts of the world as antecedent topography upon which corals can be grown turns out to be a viable strategy, we could make huge strides in restoring corals lost to bleaching events. I envision a number of ways this strategy could be implemented, such as bringing recreational divers out to the Flower Garden Banks to sightsee but also aid in coral collection for transplantation to oil platforms. As mentioned earlier, energy companies might jump on the opportunity to appear more ecologically conscious. Platforms, normally an eyesore blemishing otherwise pristine waters, can become museums of aquatic diversity, as pictured above. It is important to note that if climate conditions continue to change worldwide such that our seas become less and less habitable for corals, then this strategy will ultimately fall short. Fortunately, turning oil platforms into artificial reefs could be cost-effective enough to implement simultaneously along with other more long-term oriented solutions.

Sources:

  1. Sammarco, Paul W. “Corals on oil and gas platforms near the Flower Garden Banks: population characteristics, recruitment, and genetic affinity.”US Dept. of the Interior, Bureau of Ocean Energy Management, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study BOEM 216 (2013): 106.
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Soft corals aren’t so soft on Parkinson’s Disease

In my last blog post, I discussed the use of coral skeletons as bone grafts in patients with degenerative bone diseases. However, most of the medical advances from coral is in the field of pharmacology, that is, the study of drug interactions and effects on the human body. Cooper et al. (2014) include a comprehensive table of many coral derived chemicals that have been found to benefit humans (Figure 1).¹ As you can see, these compounds have a wide variety of medicinal applications, from cytotoxicity in killing cancer cells to neuron protection in degenerative brain disorders like Parkinson’s Disease. I talked about the anti-inflammatory properties of Sinularia for treatment of arthritis in my first blog post, but that is only one of its numerous benefits to humans.

Figure 1: Table of pharmacological properties of chemicals derived from corals compiled from numerous peer-reviewed articles (Cooper et. al, 2014)

I recently lost a family friend to Parkinson’s Disease. For those unfamiliar with this devastating disease, Parkinson’s affects the neurons that make up the brain, resulting in their inevitable deterioration. Early symptoms of Parkinson’s seem insignificant, like uncontrollable hand tremors, but as the disease progresses, patients lose the ability to control their muscles, resulting in stiffness, slowed movement, and, eventually, death. Few treatments are currently available to treat Parkinson’s; however, a group of researchers in Taiwan have isolated a molecule that has the potential to revolutionize Parkinson’s treatment.² The compound, 11-dehydrosinulariolide, was isolated from Sinularia corals and tested for its effects on human neurons (Figure 2). The results were amazing! Not only did 11-dehydrosinulariolide prevent apoptosis (cell death) of affected neurons but also decreased surrounding inflammation, which would greatly slow the progression of Parkinson’s. However, the compound is still in clinical testing, so a drug derived from the chemical won’t be available for a few more years.

Figure 2: Chemical structure of 11-dehydrosinulariolide (Chen et. al, 2012)

Along similar lines, another group of Taiwanese researchers investigated the neurologic effects from a chemical produced from the soft coral Cladiella australis.³ The compound, which they aptly named Austrasulfone, could be synthesized easily and had neural anti-inflammatory properties, so the researchers decided to test its efficacy (Figure 3). However, when they administered adequate doses of Austrasulfone to laboratory rats, they found the compound had the potential to treat a much wider array of disorders, including multiple sclerosis, atherosclerosis, and even generalized neurogenic pain. Since treatments for these disorders are very limited and results tend to be inconsistent, the development of medications that utilize Austrasulfone could revolutionize treatment for these diseases.

Figure 3: Synthesis mechanism of Austrasulfone using common reagents (Wen et al., 2010)

 

When I tell people I’m taking a class completely devoted to coral reef ecosystems, their first question is almost always, “Why should I care about coral reefs?” For people who don’t have much of a background in biology, explaining trophic pyramids and the ecological importance of coral reefs may not be very convincing. Instead, I tell them coral reefs could one day save their life. It often puts them completely off-guard and makes them intrigued to learn more, which is when I go into all of the other important aspects of reefs. As I said in my first post, this blog functions as another, albeit less known, reason for global protection of coral reefs. So next time you get asked, “Why should I care about coral”, you’ll at least have one more tool in your arsenal to persuade with.

 

References:

¹Cooper, E.L., Hirabayashi, K., Strychar, K.B., & Sammarco, P.W. (2014). Corals and Their Potential Applications to Integrative Medicine. Evidence-Based Complementary and Alternative Medicine, 2014, 1-10.

²Chen, W.F., Chakraborty, C., Sung, C.S., Feng, C.W., Jean, Y.H., Lin, Y.Y., Hung, H.C., Huang, T.Y.,  Huang, S.Y., Su, T.M., Sung, P.J., Sheu, J.H., & Wen, Z.H. (2012). Neuroprotection by marine-derived compound, 11-dehydrosinulariolide, in an in vitro Parkinson’s model: a promising candidate for the treatment of Parkinson’s disease. Naunyn-Schmiedebergs Arch. Pharmacol., 385, 265–275.

³Wen, Z.H., Chao, C.H., Wu, M.H., & Sheu, J.H. (2010). A neuroprotective sulfone of marine origin and the in vivo anti-inflammatory activity of an analogue. European Journal of Medicinal Chemistry, 45(12), 5998-6004.

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Be Wary of the New Fish in Town

Many aquariums boast exhibits of exotic fish from faraway places. While these may seem like harmless attractions behind the glass, these fish don’t always stay behind glass. Oftentimes, these foreign fish are released into local waters, altering their new environment. In my first post, I discussed the history of the aquarium trade and some general effects it has had on coral reefs. Now, I will focus on one of the most significant dangers that the aquarium trade poses to coral reefs: the introduction of invasive species. In fact, aquarium releases make up one third of invasive species globally and are one of the top five avenues for introducing invasive species into the marine environment1.

A large reason why this is an issue is because of the incredible scarcity of regulation in the aquarium industry. There are an estimated 11 million1 aquarium hobbyists in the U.S, and there’s virtually no certain way to control their purchasing actions. For example, despite the fact that water hyacinths (a registered major invasive species) are banned in multiple states, many hobbyists are still able to purchase them through the internet for as little as $41. With the accessibility and anonymity of the internet these days, it’s easy to see how quickly the private aquarium trade can blow out of control. This lack of strict regulation inevitably leads to a large number of releases of invasive species into local waters. To date, there have been an estimated 50 families and 150 species that are registered as invasive species.

Fig. 1: Table of species of registered invasive ornamental aquarium fish species. Source: Padilla et al. (2004).

So what’s the big deal with a couple new fish coming into new waters? In this case, the more is NOT the merrier. A few general threats invasive species pose to coral reef ecosystems include: reduced biodiversity, competition with local species, increased coral erosion, and changing reef topography.

One of the most successful invasive species is the lionfish. Lionfish are most commonly introduced by the aquarium trade, although ballast water can also be a pathway2. The large lionfish presence in the Atlantic is hypothesized to be due to aquarium releases off the coast of Florida in 19923.

A lionfish—an invasive species originally from the Indo-Pacific that now threatens ecosystems in the U.S coast and Atlantic due to aquarium releases. Source: https://sites.psu.edu/siowfa15/2015/10/20/lion-fish/

A study conducted in the Bahamas (Albins et. al (2008)) revealed the drastic detriments lionfish can cause in a short period of time. In this study, scientists paired up twenty reefs (one is control reef, other has lionfish) to compare the short term effects of lionfish on a reef community. The results were both shocking and distressing. Over a 5 week period, the reefs transplanted with lionfish saw a significant decrease in the recruitment of juvenile native fish3. This is particularly troubling because recruitment of juvenile fish is a crucial part of the coral reef ecosystem’s life cycle. If this middle part of reef development is threatened, then the entire reef structure is threatened!

Fig. 2: This graph shows the drastic difference between recruitment of fish on reefs with and without lionfish. Notice how the lionfish reefs exhibit significantly less fish recruitment in only a few weeks. Source: Albins et al. (2008).

Results also showed that lionfish contributed to 79 percent of the depletion of native fishes3. This is due to the lionfish’s unique predation strategy, which entails them cornering prey with their ornate fins and striking aggressively. Lionfish are quite successful invasive predators because native fish are not used to this strategy.  Not only that, but the lionfish’s preying prowess puts it in direct completion with local predators, threatening their status in the reef community3.

Some suggested solutions to the invasive species epidemic have been to, first of all, construct a whitelist of safe aquarium species to purchase. You can help by spreading this information and advocating for the purchase of safe species. Let your friends or readers know which species should be off-limits. Education and awareness is the first step in saving our coral reefs!

 

References

1 Padilla, Dianna K., and Susan L. Williams. “Beyond ballast water: aquarium and ornamental trades as sources of invasive species in aquatic ecosystems.” Frontiers in Ecology and the Environment 2.3 (2004): 131-38. Ecological Society of America. Web. 22 Mar. 2017.

2Whitfield, Paula E. “Biological invasion of the Indo-Pacific lionfish Pterois volitans along the Atlantic coast of North America.” Marine Ecology Progress Series 235 (2002): 289-97. Inter-Research. Web. 22 Mar. 2017. <http://www.int-res.com/abstracts/meps/v235/p289-297>.

3Albins, Mark, and Mark Hixon. “Invasive Indo-Pacific lionfish Pterois volitans reduce recruitment of Atlantic coral-reef fishes.” Marine Ecology Progress Series 367 (2008): 233-38. Inter-Research. Web. 22 Mar. 2017. <http://www.int-res.com/abstracts/meps/v367/p233-238/>.

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Corals of the Caribbean: White Band’s Ghost

Coral reefs are resilient yet gentle ecosystems that are affected by several diseases. They have overtaken the Caribbean reefs and have become a serious deteriorating factor. In my last post I talked about the effect of the Black Band Disease on Caribbean corals. Today, I would like to focus on another disease that also leaves its detrimental “mark”.

Figure 1. The red arrows are pointing towards the white band (the exposed skeleton). The stark contrast between the healthy coral and the affected area are seen. Copyright: Randall, C.J.& Woesik, R. van. “Contemporary white-band disease in Caribbean corals driven by climate change.” DOI: 10.1038 2 

 

The White Band Disease (WBD) haunts the coral reefs and targets Acropora Palmata (Elkhorn coral) and the Acropora cervicornis (Staghorn coral). It peels away the coral tissue leaving the white skeleton exposed, creating the infamous “white band” as seen in Figure 1.1  What’s worse is that the coral is left vulnerable making it an easy target for algae to latch on and grow.1 The algae then covers the coral skeleton and the coral has no chance to combat the disease or regrow.

You must be thinking “Oh it’s not that serious, it only affects two species of corals”…but that could not be further from the truth! These two species are major coral reef builders that area an important component for the framework of Caribbean coral reef ecosystems.2 Due to disease attacks in recent decades, populations in various regions of the Caribbean have declined by more than 90%.2 Sadly, the Elkhorn and Staghorn coral have been placed on the official endangered species list.3 To further deepen the blow, there has been no sign of any the coral recovering nor has a successful intervention been implemented.

Figure 2. Staghorn coral pictured. a) Coral affected by WBD in the ocean b) Induced WBD in a lab c) Demonstrating snail predation d) Lesion imitating what occurs with snail predation
Copyright: Gignoux-Wolfsohn, S. A.; Marks, Christopher J.; Vollmer, Steven V. “White Band Disease transmission in the threatened coral, Acropora cervicornis.” doi:10.1038/srep00804 4

 

 

WBD is transmitted quite easily from coral to coral. If healthy coral comes in contact with the infected coral, they will also be targeted by the disease. 3 Two main ways that the disease is spread is through animals or simply through contaminated water.4  Snails who rely on corals for their main source of food have become key players in the spread of WBD.In Figure 2, we can see qualitative data from an experiment that tested the effects of the snails eating habits on the coral.

The culprit has yet to be identified, but scientists remain on the lookout. Scientists are almost sure that it is caused by a bacterial infection but the exact pathogen remains unknown. 3  The deterioration in the coral is caused by an attack of microbes but what remains unclear is where the microbes come from and how they are propagated. There is a theory that the bacteria already exist within the coral, but under extreme environmental conditions they turn against, and attack their coral host.2

Furthermore, Marine scientists have various hypothesis of factors that perpetuate the corals vulnerability to this disease. Possibilities range from an overpopulation of algae to changes in Sea Surface Temperature (SST) due to climate change.1  In the Caribbean there has been a steady increase in SST throughout the years, and this progression is seen in Figure 3 below. There have been studies that confirm that climate change and the ever increasing temperatures of the ocean water play a crucial role in the escalation of WBD.2

Figure 3. Sea Surface Temperature (SST) of the Caribbean. a) Average rate of change in SST FROM 1967-2004 b) Mean SST for March 1982
Copyright: Randall, C.J.& Woesik, R. van. “Contemporary white-band disease in Caribbean corals driven by climate change.” DOI: 10.1038 2

It is evident that scientists are working hard to add to the existing research and hypothesis in order to better understand this disease that is harming the beloved Caribbean coral reefs. However, conscientious choices from everyone else will also help in this fight to protect coral reefs. Without a doubt,  climate change is a serious issue that affects various habitats and ecosystems. So I encourage you to reduce your  greenhouse gas emissions by recycling, carpooling and making other eco-friendly decisions!

  1. “Coral Diseases.”Florida Museum of Natural History. University of Florida, n.d. Web. 22 Mar. 2017. <https://www.flmnh.ufl.edu/southflorida/habitats/corals/diseases/>.
  2. Randall, C.J.& Woesik, R. van. “Contemporary white-band disease in Caribbean corals driven by climate change.” Nature Climate Change 4 (2015): 375-379. ProQuest. Web. 22 Mar. 2017. DOI: 10.1038
  3. Kline, David I. & Vollmer, Steven V. “White Band Disease (type I) of Endangered Caribbean Acroporid Corals is Caused by Pathogenic Bacteria” Scientific Reports. 7 (2011). Nature.com. Web. 22 Mar. 2017. doi:10.1038/srep0000
  4. Gignoux-Wolfsohn, S. A.; Marks, Christopher J.; Vollmer, Steven V. “White Band Disease transmission in the threatened coral, Acropora cervicornis.” Scientific Reports 804 (2012). Nature.com. Web. 22 Mar. 2017. doi:10.1038/srep00804

 

 

 

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El Niños Past and Present

While it is clear that the current ENSO-driven mass bleaching event has been devastating and widespread, to put it in perspective, it’s essential to look back and compare it to similar incidents in the past. Some of these, which you may or may not remember, took place in 1982-83 and 1997-98; the latter of which resulted in NOAA declaring the first global mass bleaching event1. Analyzing data and contemporary reports from these two El Niños gives us valuable insight into the present catastrophe unfolding on our planet.

Widespread bleaching was first noticed and documented by scientists during the ENSO cycle of 1982-83. The El Niño event was the strongest that had occurred in many years, but the threat of coral bleaching was just coming to be understood. In 1997, the first bleaching events of a new ENSO cycle occurred, and researchers began analyzing data following the conclusion of the second wave of bleaching in 1998. One particularly illuminating example is a 2001 study by University of Miami researchers that sought to quantify the difference in scope and severity between the ‘82-83 and ’97-98 bleaching events2. Focusing on Panama and Ecuador, the study primarily documents the sea surface temperatures (SST) and broad-scale mortality rates of reefs in the two regions.

Figure 1: Sea Surface Temperature Comparison between the 1982-83 and 1997-98 ENSOs for Two Different Locations on the Panama Coast (A and B). Source – Glynn et al. 2001 (Ref. 2)

As is quite apparent in Figure 1, mean SST in Panama was noticeably higher in 1997 than 1982 (first years of the respective events). This distinction is not as noticeable for ’98 and ’83, and the large part of the SST data suggests that the two ENSO events were rather close in magnitude2. The data the scientists collected also reveals that 1982-83 had a much higher overall coral mortality rate (85%) in the region than ’97-98 (less than 10%)2. The study points out that seasonal upwelling, which is the rising of deep, cool water, may have contributed to this regional moderation of the 1998 El Niño2.

These conclusions demonstrate that great variation occurs between, and spatially within, mass bleaching events, even if ENSO climate effects occur in broadly similar patterns. While most coral were bleached or affected in some way, not all reefs were wiped out in 1998, as one might expect from such severe conditions, and the precedent set in 1983; natural processes seemingly prevented this from happening. A sample comparison of individual corals from the same region and species experiencing very different degrees of bleaching is shown below in Figure 2.

Figure 2: Degrees of Bleaching in Panama Coral: A) mottled bleaching, B) highly bleached colony, C) two adjacent colonies, colored (left) and one bleached (right). Source – Glynn et al.  2001 (Ref. 2)

How does this all relate to the 2016 El Nino that just concluded? I think one essential takeaway from this study is that just because El Niños are getting stronger and longer in conjunction with climate change (as evidenced by 2015-16)3, sea temperature severity is not necessarily directly correlated with overall reef mortality in a region. Many other factors contribute to the health of reefs during an ENSO than just variation in air/sea temperature, which is usually what’s discussed in the public sphere. Considering the importance of understanding and predicting global mass bleaching events, looking at historical analyses and comparisons helps put their effects into a more accurate context.

References:

1- “El Niño prolongs longest global coral bleaching event.” News and Features – NOAA, pub. online 23 Feb. 2016. Web. 20 Feb 2017. http://www.noaa.gov/media-release/el-ni-o-prolongs-longest-global-coral-bleaching-event

2- Glynn et al. “Coral Bleaching and Mortality in Panama and Ecuador during the 1997–1998 El Nino–Southern Oscillation Event: Spatial/Temporal Patterns and Comparisons with the 1982–1983 Event.” Bulletin of Marine Science, 69(1): 79–109, 2001. Web. 18 March 2017. http://www.ingentaconnect.com/content/umrsmas/bullmar/2001/00000069/00000001/art00007

3 – “El Nino Prolongs Longest Global Coral Bleaching Event.” American Geophysical Union, pub. online 23 February 2016. Web. 22 March 2017. https://news.agu.org/press-release/el-nino-prolongs-longest-global-coral-bleaching-event/

 

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Can Climate Change Cause Diseases in Our Coral Reefs?

Corals are living organisms and as such they are susceptible to diseases. High temperatures can affect the severity of diseases. High temperature is a stressor and as such it can decrease an organisms immune response and increase the virulence of a pathogen. This relationship between temperature and disease severity has been found in both terrestrial and aquatic systems1. There are a variety of different coral diseases2. A number of recent studies indicate that warmer water and bleaching events may help disease causing-organisms attack corals2. A link between temperature and severity of coral disease has been investigated through many different studies that have shown that diseases are spread more quickly throughout a colony during the summer1. These pathogens can have devastating effects on the ocean’s coral reefs, affecting not only the corals but many other organisms that depend on coral reefs2.

Acropora palmata, or Elkhorn coral found in Florida have been particularly affected by white pox disease (figures 1 and 2)3. Kathryn Patterson and colleagues studied the growth of lesions on Elkhorn Coral colonies in the Florida Keys National Marine Sanctuary3. They used photographs and videos taken between 1996 and 2000 to test the dispersion of the disease and tissue loss on infected colonies. The team found that some lesions increase in size very quickly3. These lesions are less common than the more slowly progressive lesions, but are still the most important to coral tissue death3.  The more common lesions, which increase at a much slower rate but are more numerous, have less of an impact on coral tissue death3. Patterson and colleagues also determined that the disease was caused by the bacteria S. marcescens, a bacteria commonly found in human fecal matter; therefore, sewage may be the source of the microbe responsible for the S. marcescens disease known as white pox disease3. Their most important result, however, was that loss of living coral due to white pox disease was greater during the summer months than during the winter months3. This result indicates that tissue loss due to white pox disease is correlated with temperature3. As ocean temperatures rise due to climate change, the effect of diseases such as white pox will be magnified and occur more rapidly. In short, diseases will be more deadly.

Figure 1: Healthy Elkhorn coral colony (Acropora palmate). Photo by US Fish and Wildlife Service. Licensed by CC BY 2.0.

Figure 2: An Elkhorn coral colony with white pox disease. White pox disease is characterized by white patches or lesions and tissue loss everywhere on the coral colony. Photo by Jim Stuby. Licensed by Public Domain.

Research by John Bruno and his colleagues suggests that both temperature and coral cover, the percentage of an area that is covered by live coral colonies, affect the frequency of coral disease1. Other studies have shown that diseases spread more quickly throughout coral colonies in the summer and this could be explained by higher temperatures, but it could also be explained by other seasonal factors1. Bruno and his colleagues wanted to specifically see if temperature had any effect on the frequency at which diseases developed1. To investigate this aspect of disease, they developed studies to look at the relationship between how frequently white syndrome developed in certain kinds of corals and when warmer than usual water temperatures occurred across the Great Barrier Reef1. White syndrome is a disease of corals that is characterized by a white band of exposed coral skeleton that progresses across a coral colony1.  It has been found in 17 species of Pacific reef-building corals1.  The scientists looked at forty-eight reefs for six years, in particular, studying the times when the sea surface temperature was abnormally high1. They found that the frequency of disease increased 20 times over the usual progression of the disease in years following a particularly warm summer1. Moreover, the frequency of disease varied between reefs with different coral cover1. Those reefs that had the highest coral cover also had the greatest frequency of white syndrome1.

These researchers believe that the higher temperature may have caused physiological stress which compromised the corals’ immune systems1. Corals may need the cooler waters during wintertime to attract greater amounts of helpful symbiotic algae present in their tissues as well as promote greater growth of the coral tissue, both of which are needed to help the corals fight disease1. Warmer winters may inhibit algae accumulations and growth, and the corals may therefore be more susceptible to disease and growth of pathogens1.

High coral cover may help white syndrome to spread from colony to colony. One way that coral cover may help diseases spread is through the so-called “line of death”1. Although corals appear to be lifeless rocks, they are vicious defenders of their space when they come into contact with another colony1. They use stinging tentacles to harm competitors, creating lesions on their competitors1. Pathogens may be able to take advantage of these lesions to infect the colony1. The disease was the most widespread during the warmest summer throughout the study1. Bruno and his colleagues suggest that coral cover was such an important part of predicting disease outbreaks that warmer temperatures may actually inhibit white syndrome by decreasing coral cover due to mortality from bleaching1. This hypothesis has not been tested, but at the end of the day, increased coral mortality is increased coral mortality, no matter the source. In addition, while white syndrome may be heavily influenced by coral cover, other diseases may not be affected at all and may be able to take advantage of the weakened coral caused by higher temperatures.

So what does all of this mean in terms of global warming? It means that not only do corals have to deal with bleaching and the stress of higher temperatures, but also this stress may help them get sick and may play a part in the severity of the disease.  The Great Barrier Reef is a marvelous natural environmental resource for many organisms that depend on it for food sources as well as protection.  Its loss, or even loss of part of it, would have devastating effects not only on oceanic organisms and animals, but would be a severe loss to humanity as well.  Coral reefs provide a livelihood for fishermen and a great source of tourism dollars.  We must address global warming and the subsequent warming of the oceanic waters to prevent such an overwhelming loss. 

Footnotes:

  1. Bruno, J.F., Selig, E.R., Casey, K.S., Page, C.A., Willis, B.L., Harvell, C.D., Sweatman, H., and Melendy, A.M. (2007). Thermal stress and coral cover as drivers of coral disease outbreaks. PLoS Biol 5, e124.
  2. Global Warming and Coral Reefs – National Wildlife Federation. https://www.nwf.org/Wildlife/Threats-to-Wildlife/Global-Warming/Effects-on-Wildlife-and-Habitat/Coral-Reefs.aspx.
  3. Patterson, K.L., Porter, J.W., Ritchie, K.B., Polson, S.W., Mueller, E., Peters, E.C., Santavy, D.L., and Smith, G.W. (2002). The etiology of white pox, a lethal disease of the Caribbean elkhorn coral, Acropora palmata. Proceedings of the National Academy of Sciences 99, 8725–8730.
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