Tuesday, April 26, 2016

Nesting activity of sea turtles, Caretta caretta and Chelonia mydas, at Patara Beach over four nesting seasons

The loggerhead turtle known as Caretta caretta is the most common sea turtle that exists in the Mediterranean. Some of the major nesting areas for these turtles are in Greece, Turkey, Libya, Egypt, Israel, Italy, etc. The green turtle, which is known as Chelonia mydas, is well known in the Mediterranean. But this turtle is densest in Turkey, Cyprus and Syria.

Caretta caretta

Chelonia mydas

 Based on the first research of the Turkish coast of turtle nesting areas there are seventeen important nesting beaches on the Turkish Mediterranean coast, this number was then again upgraded in 2003 to 20 important nesting beaches and then to 22 in 2004. In a study the number of C. caretta females are annually nesting on the coast varies between 2280 to 2787 another study estimates in 2010 that C. caretta is 7200 and about 1500 for C. mydas.

The first detailed research that shows nesting activity on Patara Beach in Turkey started in 1989. The highest number of nests was shown in 2006 and it had 127 nests and the lowest number of nests was 33 in 1994. The goal of this study was to show information on nesting activity and show distributions of nests, etc.

In this study about 556 loggerhead emergences were recorded per year over a four year period. About 32 percent of this number resulted in nests and about 180 nests were made per year. On the Patara beach there were 113 nests in 2010, 138 in 2012, 207 in 2013 and 195 in 2014. In the Kumluova beach there were 3 in 2010, 31 in 2012, and 32 in 2013. Kumluova has some wetlands that exist within the beach area and there is more predation which is why there is a higher amount of nests in  Patara. There are also the green turtle emergences, which only had 17 in the 4 year period which were all in Patara. There were only 3 nests that were resulted out of these turtles 1 in 2010 and 2 in 2012.

Figure 1

Figure 1 shows that the nesting season starts in May but the amount of nesting that occurs in may is low. Figure 1 also shows an incline of nesting activity towards the end of June but the peak nesting time take place in July and then dies off again in August which is the end of the nesting period. In May nesting success what at approximately 4.03%, in June it was about 44.93% in July it was 45.62% and in August it was 5.42%.

Table 2

Shown in Table 2 the researchers excavated loggerhead nests. In 2010 they excavated 115 nests, 162 in 2012, 224 in 2013 and 190 in 2014. The overall total of eggs counted was 47,129 eggs and 676 nests. One of the key parts of this study was the amount of hatchlings that were produced from each nest. And they found that 17,929 of the 47,129 eggs were able to make it to sea (38.04% of eggs). There were also 218 green turtle eggs counted and 121 of those eggs produced hatchlings and 94 were able to make it to sea (43.12% of eggs).

Predation affected the nests over the four-year period. 142 of the loggerhead nests were partially predated on and 256 were completely predated on. 55.36% of the nests were affected by predation. Some of the predators include Fox (Vulpes vulpes), dogs (Canis lupus), badgers (Meles meles), and wild pigs (Sus scrofa). There was also some predation by crabs. Some of the nests were provided with metal grates to help with survival. The hatchlings with the protection had a higher survival rate than those that were in natural settings because the predation was lower.

OLGUN, K., BOZKURT, E., CEYLAN, S., TURAL, M., ÖZCAN, S., KARASÜLEYMANOĞLU, K. Ş., & GEROĞLU, Y. (2016). Nesting activity of sea turtles, Caretta caretta (Linnaeus, 1758) and Chelonia mydas (Linnaeus, 1758) (Reptilia, Cheloniidae), at Patara Beach (Antalya, Turkey) over four nesting seasons. Turkish Journal Of Zoology, 40(2), 215-222. doi:10.3906/zoo-1505-8

Sunday, April 24, 2016

Great Barrier Reef Losing Their Tolerance to Bleaching

A new study has found that the Great Barrier Reef corals will lose its tolerance from bleaching events. The study says that the Great Barrier Reef corals were able to survive past bleaching events because they were exposed to a pattern of waters getting gradually warmer, before a big bleaching event. But due to recent climate change this pattern is likely not to occur anymore because of the drastic changes in temperature.


            In a paper published in Science today, researchers from ARC centre of Excellence for Coral Reef Studies as well as the U.S. National Oceanic and Atmospheric Administration investigated what this warming pattern means for Great Barrier Reef coral bleaching events that are to occur in the future. It is explained that when a bleaching event occurs it is like a marathon for corals, and that when corals are predisposed to a pre-stress period before bleaching they have a lot easier time tolerating the warmer waters and are able to survive the heat shocks.
            These types of “pre-stress” conditions are expected to disappear when the seawater temperatures rise by as little as half a degree, which has been predicted to occur soon. So because they will not have these “pre-stress” conditions they will be directly exposed to heat shock events. According to NOAA future summers will bring more bleaching events and they will be more severe and the coral will be at greater risk for dying.
            The way they can predict this is through 27 years worth of data that looked at sea surface temperatures, past bleaching events, and studied how corals responded to warming conditions. Other predictions are that different reefs on the Great Barrier Reef will lose their protective mechanism (pre-stress/practice run) at different rates. It is also predicted that if they lose their protection they will bleach faster as well as stay in this state longer.
            According to Bill Leggat, he says that knowing what temperature patterns are present in different reefs these allows them to know the impact and capacity bleaching events will have as well as survival. Knowing these different aspects of bleaching and survival can help increase the likelihood of coral survival through these events by helping reduce stressors, like pollution. There results show the importance of global action against green house gasses and reduce emissions.


Tuesday, April 19, 2016

Marine-derived collagen biomaterials from echinoderm connective tissues

Echinoderms are marine organisms such as sea stars, sea urchins, and sea cucumbers. They possess connective tissues referred to as mutable collagenous tissues (MCTs). These MCTs have the potential to be developed into collagen barrier-membranes by guided tissue regeneration (GTR) for the use of humans. This study compared echinoderm-derived collagen membranes (EDCMs) to commercially used membranes from bovine collagen substrates (BCMs). Traditional commercial membranes have several areas where they lack causing the search for alternative sources. They can cause allergic reactions, conflict with religious beliefs, have disease transmission connected reasons, and they have a high cost of recombinant technologies. Echinoderm MCTs are relatively easier to obtain high amounts of native fibrils which maintain their original structure, this rapidly produced fibrillar collagen gives high similarities in terms or ultrastructural and mechanical characteristics to the physiological prestige of connective tissue.

Echinoderm Tissues
This study optimized different extraction techniques to efficiently obtain clean, relatively pure and highly concentrated native collagen fibril suspensions from three echinoderm MCTs species. The species studied were the sea urchin Paracentrotus lividus, the sea star Echinaster sepositus, and the sea cucumber Holothuria tubulosa; all of which differ in overall collagen fibril, fiber organization, and the presence of skeletal elements. Sea star aboral arm wall and partly sea urchin peristomal membrane showed highly packed fibrils and calcareous ossicles, where sea cucumber body wall contains loosely packed and wide spread fibrils and small calcareous spicules. This explains why fibril extraction is easily obtained by mild non-denaturing methods for sea cucumber and stronger treatments for both sea urchin and sea star. All three species showed the ability to maintain fibrillar conformation and integrity throughout the extraction process which is promossing compared to less stable mammalian collagen.

Collagen Network of Different Membranes
Glcosaminoglycan (GAG) is a fundamental substance to maintain fibril integrity by cell migration, adhesion, proliferation, and differentiation. GAG is often added to mammalian collagen scaffolds to improve their performances in tissue engineering applications. EDCMs already contain GAG in their native fibrillar collagen. Average porosity of EDCMs was smaller than the size of human cells, allowing them to likely be more efficient as cell barriers for biomedical applications where division of two anatomical compartments is needed such as GTR. In GTR these barriers help the healing process avoiding mixture of adjacent regenerating tissues and are useful to prevent post-surgical tissue adhesions which are common surgical complications.

EDCMs also outperform mammalian collagen due to their limited thickness, high mechanical resistance, and hadleability during surgery. The higher the tensile strength and the resistance to uni-axial tension the better the biomaterial can support stresses before rupture. The mechanical resistance of thicker bovine-derived collagen membranes is much lower compared to EDCMs especially in mechanically demanding tissue engineering application, suggesting the potential utility of echinoderm collagen.

In vitro tests with human skin-derived fibroblasts were conducted to see if cells seeded on the substrates were viable and able to actively proliferate in long-term periods of 21 days. Cells seeded to EDCMs and BCMs were similar in morphology, organization, and substrate adhesion pattern. EDCMs presented a more elongated shape and less and shorter filopodial processes. This can indicate a reduction in substrate adhesion which can be beneficial in cell barrier for GTR. Cell numbers after 4 days were different in all three organisms. Sea urchin membranes had similar numbers to bovine collagen substrate and plastic controls, both sea star and sea cucumber membranes showed less. Further testing is needed to determine if this is a transient and temporary cell behavior or if it’s due to a toxic effect.

Overall sea urchins and partially sea stars display a major advantage when compared to bovine derived collagen. Further in vitro and in vivo studies are necessary to more deeply evaluate EDCM exploitability, including permeability, biodegradability and immunogenicity, all of these being key features to validate new biomaterials for human clinical applications.

Ferrario, C., Leggio, L., Leone, R., Di Benedetto, C., Guidetti, L., Cocce, V., . . . Sugni, M. (2016). Marine-derived collagen biomaterials from echinoderm connective tissues. Marine Environmental Research, In Press, In Press. doi:10.1016/j.marenvres.2016.03.007

Sunday, April 17, 2016

The Great Migrating Loggerhead Sea Turtles & Their Quest for Conservation

The Loggerhead Sea Turtles are a great migrating sea turtle in the Atlantic Ocean and are found at the Outer Banks. As we talked about in class, they ride the Gulf Stream Current up to mating areas and ride the Canary Current back to the U.S. coast to lay their eggs and forage. By riding these currents, they cruise more swiftly to the areas they desire to be at. 

Turtle migration patterns are an important area to study in marine biology because of the drastic decrease in sea turtle population numbers. Understanding their migration patterns and behaviors can help us to find ways for better conservation. As mentioned in class, all of the seven marine sea turtle species are either endangered or threatened. Finding ways to recover these populations is the desired goal in this study.
Photo Cred: Michael Melford, National Geographic

Caretta Caretta
This study wanted to know better ways to conserve and recover the Endangered Loggerhead Sea Turtle populations. To better understand this process, they set up an experiment to study the migration and foraging patterns of 68 Loggerhead female turtles. This study was done between 1998-2008 by DuBose B. Griffin and many other authors. 
Photo Cred: Sea Turtle Conservancy

They tagged the female Loggerhead's with platform transmitter terminals at nesting beaches in Georgia, North Carolina, and South Carolina. They viewed the movement of these turtles by satellite and observed for patterns. 42 of the 68 Loggerhead's used migration patterns along the continental shelf. 4 of those 42 turtles made excursions but eventually returned to the shelf and foraged in those areas. 2 of the 42 ventured off all the way to the Bahamas. 3 of the 42 left the shelf during winter and returned in summer and 1 out of the 42 left the shelf in November and returned in February. They noticed that these turtles had a very unique migration route that was not seen in any other marine sea turtle species. Most importantly, they saw that these 42 migrated north of Cape Hatteras between May and October. This shows a distinct migrating and foraging behavior in the warmer months. Then in the colder months of winter, migration and foraging patterns switched and became more southern focused.

Photo Cred: DuBose B. Griffin Paper

This figure from the paper shows the movement along the latitude throughout the months of the years averaged between 1998-2008. They observed a pattern for migration. Section A shows the Post-Nesting Migration Segment. Section B shows the North to South inter-foraging migration segment. Section C shows the South to North inter-foraging migration segment. We can see that the movements are relatively consistent and showed that all of the foraging areas were off the continental shelf. This figure shows the switching of migration from the Mid-Atlantic Bight to the South-Atlantic Bight during different seasons. 

On top of the migrating patterns found in the Loggerhead's, they also found distinct foraging areas that the turtles used in 63 of the 65 turtles. Over a long time span, consistency is a great finding for conservation strategies. They also took notice that male Loggerheads and Green Sea Turtles also foraged in the same areas although migration patterns were not measured. They found that there were distinct spots on the continental coast where they were foraging and nesting and it was not just on any part of the shelf or beach. This makes this study very successful in bringing very specific locations for conservation. One of the most important findings was that the Loggerhead migration patterns seemed to line up with the migration patterns of commercial fish that are known to kill large numbers of these turtles annually. From our past studies in class on the long lives of turtles and low success rate of hatched babies, this is something to consider. 

As it is a great discovery to find specific migrating patterns and foraging locations for these female Loggerheads, it is also dangerous to know its co-alignment with its predators. Conservation strategies are in place to help protect these species as this paper was published in 2013. Why they migrate in predator filled waters and have not adapted to a new migrating pattern is unknown and is to be further researched.

Griffin, DuBose B. 2013. Foraging habitats and migration corridors utilized by a recovering subpopulation of adult female loggerhead sea turtles: implications for conservation. South Carolina Department of Natural Resources. Retrieved from Academia on 17 April 2016. 

Saturday, April 16, 2016

Rising sea levels and the longevity of the Outer Banks

When one thinks of the North Carolina coast, specifically the Outer Banks, one thinks of nostalgic summers on a warm beach with surreal settings as described in a Nicholas Sparks novel. Most don’t think of the gradual fading of this land from our maps due to combined efforts of storms, development, and sea-level rising. Portions of the beach have receded over 2,500 ft. in the last 150 years, that’s an average of a little over 16 ft. a year. Additionally the width of the Outer Banks has narrowed to 25% of its original width. Houses and structures once safely inland are now meeting the sea, the single road State Highway 12 has been wrecked and washed out during multiple storms, All of these incidences are set to increase as sea-levels are set to rise world-wide due to global warming. Large economic setbacks for the Outer Banks tourism industry are subsequently further strained as time goes on.

This news of the deterioration of the islands however is not “news” at all. For years scientist have been predicting these results and have warned residents and government officials of this impending destruction. In 2010 Stanley Riggs, a coastal geologist, and fellow members of a science panel produced a report warning that North Carolina could face 1 meter of sea-level rise by 2100 from glacier melting and the expansion of warmer water. The report was met with controversy from coastal developers, skeptics, and state officials. Lawmakers in Raleigh considered a bill that would have prohibited state agencies from planning for accelerated sea-level rise. The irony as Riggs puts it is that the coast is vanishing now, not a hundred years from now.

The good news is that these sandy islands are resilient and able to adapt and survive through storms and sea-level rise by moving, given that they run a natural course. The bad news is that with the construction of Highway 12 in the 1950’s, the natural shift in the island westward has been severely limited, facilitating continual erosion on the ocean side and no growth on the sound side. The road also brought a $926 million tourism industry to maintain, which is dependent on the existence of the island, which the road itself is contributing to its diminishment.

Riggs has proposed that the state removes portions of the highway and stop maintaining large dunes to protect it. The removal of the road and dunes would allow sand to wash over the islands and rebuild them naturally on the sound side. He also suggests people visiting on the mainland and traveling by ferry to the Outer Banks rather than permanent residencies on the islands. Unfortunately this idea is not welcomed by most locals who are dependent on the tourism industry. For the mean time temporary fixes are being made by the delivery of sand from elsewhere to slow the progress of the narrowing of beaches. Riggs concludes by saying, “we will not be able to defend most coastal places throughout time. We will, in fact, retreat from most coastal places when the sea level gets more than one or two meters above where it is now.”

Mignoni, E. (2014, July). Rising Seas: Will the Outer Banks Survive? Retrieved April 16, 2016, from http://news.nationalgeographic.com/news/special-features/2014/07/140725-outer-banks-north-carolina-sea-level-rise-climate/

Monday, April 11, 2016

Manatee Diving Patterns and Watercraft Collision Risk

It is well known that manatees are threatened by watercraft collisions, but could their diving patterns influence their risk of colliding with a watercraft? Manatees are at a higher risk when they are closer to the surface where the watercrafts are located or when they cannot move away when a watercraft is nearing them.  
            Nine manatees were tagged with GPS and time-depth recorders to study their diving patterns in Tampa Bay, Florida to see how these diving patterns may influence their risk of watercraft collision. The manatees were studied over four winters from December to March of the years 2002 to 2005. Manatees do not do well in the cold so they tend to travel to locations where there is warm water, such as near Tampa Electric’s Big Bend Power Station. Surveys taken in this area have shown that more than 600 manatees congregate in this area to stay warm during the winter months, so this was a prime location to conduct this study. The warm waters in this area range between a no-boat zone and a zone where boating is permitted.
            The researchers found that the manatees spent 49% of their time outside of the no-boat zone of the canal. The mean dive depth of the nine study manatees was 1.09 meters and the deepest dive was 16.2 meters. A dive profile was created that showed that the manatees will take multiple deep dives in a row, but TDR records showed that the manatees spent most of their time near the surface. As stated earlier, manatees are at greater risk of watercraft collision near the surface. They also found that the shorter dives took place most often at night, while the deep dives most often took place during the day.
            Interestingly, the researchers discovered that the manatees were at greater risk of being struck by a watercraft when they were in an area with a seagrass bed. During faster travel the manatees spent less time in the projected striking depth area where they would be more susceptible to being struck by a watercraft. They spent more time in the striking depth are during the night and less time during the day.
            Overall, it was concluded that the manatees spent about 78% of their time in the striking range where they are at the highest risk of a watercraft collision. Since the manatees spend most of their time in shallower water, they are less likely to be able to escape when a watercraft is coming near them. Seagrass beds are often found in shallow waters which is why the manatees are at a higher risk of being struck by a watercraft when they are in the seagrass bed area.
            Manatees seem to occupy shallow areas the most, so when watercrafts are driving through these areas the manatees are at a higher risk of being hit and aren’t able to escape easily. When manatees rest during the day they tend to dive to deeper depths, decreasing their collision risk. Manatee diving patterns do influence their risk of being struck by a watercraft, but the environment in which they occupy also influences their risk.

Edwards, H. H., Martin, J., Deutsch, C. J., Muller, R. G., Koslovsky, S. M., Smith, A. J., & Barlas, M. E. (2016). Influence
of Manatees' Diving on Their Risk of Collision with Watercraft. Plos ONE, 11(4), 1-15. doi:10.1371/journal.pone.0151450

Sunday, April 10, 2016

Jellyfish Venom

    I have always been interested in jellyfish. They are one of the most unique organisms with their transparent bodies and swift movements throughout the ocean. Some jellyfish are clear but there are others that are more vibrant with colors like pink, yellow and purple. They can be found in both cold and warm parts of the ocean, in deep water, and along the coastline. Jellyfish have been drifting along ocean currents for many years and even before dinosaurs roamed the earth. They eat shrimp, fish, crabs, and tiny plants. In China they are fished because they are seen as a delicacy. They are even used in Chinese medicine.

   The tentacles of jellyfish have tiny stinging cells. These cells are used to stun/paralyze their prey before they eat them. A sting from a jellyfish can be very painful to humans and even dangerous. Jellyfish don't purposely attack humans though. Most of the stinging occurs because of people accidentally touching jellyfish. Sort of like when a bee lands on you, just the sensation of being touched causes the jellyfish to react and sting automatically. Although a sting from a jellyfish isn't always deadly, it can be if it is from a dangerous species.

   Nemopilema nomurai is one of the largest species of jellyfish. I found an article that examined the effects of their venom. This species is found offshore of Korea, Japan, and China. An increase in their population increases the risk of people being stung. The cardiovascular effects and cytotoxicity along with the hemolytic activities of the venom has been seen in rodent models. For this study, the venom from the Nemopilema nomurai jellyfish was tested on rat cardiomyocytes using gel electrophoresis and matrix-assisted laser desorption. Cells that were treated with the venom showed dose dependent inhibition of viability. The cellar changes at the proteome level were investigated after six and twelve hours of venom treatment. This was the first report that revealed the cardiac toxicity of the venom at the proteome level. The venom from this species of jellyfish directly targeted proteins involved in cardiac dysfunction and maintenance.

Posted Image

       One of the most common misconceptions is how to treat a jellyfish sting. The myth is that you should have someone urinate and or urinate on your own sting to relieve the pain. The best treatment for the sting depends on the type of jellyfish that stings you. The better simple remedies to treat the sting include: removing the stingers, taking a hot shower or applying ice packs, taking pain relievers and adding lotion, and rinsing with vinegar or applying baking soda paste. Removing the stingers or any part of the jellyfish tentacle that remains is a good way to relieve the pain. This should be done by rinsing with sea water. Fresh water should not be used and rubbing the area with a towel is also not suggested as these actions can activate more stingers and cause more pain. The hot shower should be as hot as you can handle, and the ice packs can also relieve pain. Lotion can help with any itching or discomfort. Rinsing with vinegar for 30 seconds or applying baking soda paste with seawater can both help deactivate the stingers of certain types of jellyfish.


       Hopefully these are helpful tips that will stick with you, especially as we explore the Outer Banks in a little over a week!

Choudhary, Indu, et al. "Proteomics Approach To Examine The Cardiotoxic Effects Of Nemopilema Nomurai Jellyfish Venom." Journal Of Proteomics 128.(2015): 123-131. Academic Search Complete. Web. 10 Apr. 2016.