Dolphins' Ability to See Through Other Animals

It is common knowledge that dolphins rely on their sonar ability to pick up wave frequencies throughout the water. They rely on this advantageous ability to hunt and communicate. With this echolocation characteristic that they posses, that ranges anywhere from 40 to 130 kHz, they emit high frequencies by blowing air through their tissues around their nose called sonar lips at a great force. A dolphin can be seen moving its head back and forth, known as "head scanning" when it scans the view in front of them, and thus produces clicks of frequency. The amount of frequency that they hear, is what gets mentally transmitted to their vision and therefore allows them to see a structure. 

So what if it was now known that they could not only produce sound, but utilize that ability to have x-ray vision as well? There is a small sac of fatty tissue that is found below the dolphins' jaws that collects the sound waves that bounce off objects. In response, it sends them through the dolphin's inner ear to be heard at a high frequency to detect. This causes a snow ball effect that it leads to being passed on to the brain through the dolphin's neurons. the signal that gets transmitted gets translated to what is know as a "acoustical holographic image." Researchers have discovered that this is what allows them to perceive the image of exactly what is in front of them. When used in short distances across the ocean/water, it is effective.

 This leads to the remarkable ability that with high frequencies and at short wavelengths, dolphins can see through other animals. It travels through the soft bodies of other fish, and the frequency waves bounce off of its hard surfaces like its skeletal structure. So like seeing the bones of the animal in front of them allow the dolphins to take a mental picture with increasing clicks of frequencies that it produces and receives. Specifically Bottle-nose dolphins are the species that use this characteristic most, based on their behaviors. For example, when a dolphin clicks along the seabed, to find hidden fish that hide up to three feet below the soft sediment. Not only can they find their prey using this sense, dolphins use a type of cross-model matching. Researchers have tested this theory with humans with the example that an object that you feel without looking at will be engraved as a mental thought in one's mind.

What I found interesting was that with this matching, dolphins can cross reference objects and so seeing a skeletal structure is incredibly advantageous. The concept is the same for dolphins, except at a higher level in which they can use the frequencies to remember the image. I never in a million years would have thought that dolphins could do something this advantageous. By taking a mental picture of objects through the use of sound is something that I find really interesting.

References:

Sweeting, Kelly M. (2014, March). Dolphin Communication Project

Handley, Andrew. (2013, Oct. 28). 10 Interesting Facts About Marine Life. Listverse. 

Humans Now the Top Predator in our Oceans

      Sharks have the reputation of being the oceans "top predators", until recently. As the human population continues to grow, other populations of animals are seeing a decrease. One animal that is experiencing the effects of human growth is the shark. Sharks, more specifically, are sought out for the fins. In a human practice called finning, many species of sharks have their fins cut off and are further thrown back into the ocean. Once thrown into the ocean, these sharks either starve to death, bleed to death, get eaten alive, or drown (if not in constant motion, gills cannot extract oxygen from the water). On top of this inhumane way of obtaining shark fins, they are getting killed at unsustainable levels.
      Shark finning takes place out at sea so the fisherman only have the fins to transport back to shore, since the rest of the body is deemed almost worthless. On top of this, all sharks, regardless of their species, age, or size, are being preyed upon by humans. This can cause issues as many of these species of sharks are not able to reproduce at a rate to combat their depletion. Shark finning is widespread and not usually monitored. It is a major delicacy in Asian regions, as shark fin soup holds cultural value. In an effort to curb the market for shark fin, the Chinese government began banning the serving of shark fin soup at official banquets in 2012. These efforts are only going so far, as it is seemingly hard to put an end to a practice that holds so much culture.
   

  

Picture: severed shark fin

      Each year, humans kills an estimated 100 million sharks. This number can have devastating effects on the ecosystem. For example, the loss of the smooth hammerhead shark caused their prey, rays, to increase in population size. Rays now eat more scallops, clams, and other bivalves. Therefore, we are seeing a decrease in our bivalves, which have the ability to filter liters of ocean water each day. It is necessary in this sense, that we maintain our shark populations in order to maintain the integrity of our ecosystems. 

     In an effort to save our depleting shark populations, we can raise awareness about shark finning by educating people. Some people even admit that they never realized what impact their consumption had on the environment. Current progress has been made, such as the 2010 shark conservation act. This act states that all sharks caught in U.S waters must be brought to shore with fins still attached. Although some progress has been made in protecting depleting shark populations, more needs to be done to ensure the protection of these magnificent and important animals. 

Geometry in Nature: Pufferfish Crop Circles

Geometry is evident in nature, such as in snowflakes, honeycomb, and plants.  A rather interesting example of geometry in nature has recently been discovered: geometric circular structures composed by the male pufferfish, Torquigener sp.  Male pufferfish have been found to construct large geometric circular structures on the seafloor, which plays a role in female mate choice.  The male pufferfish creates irregular patterns in the circular nest that are composed of fine sand particles, which is an important part of female mate choice.  These geometric circular nests are never reused because the valleys within the nest may not contain enough fine sand particles for multiple reproductive cycles.

                                  

Male pufferfish, Torquigener sp., digging a valley.

In 1995, a geometric circular structure was found on the seafloor near southern Amami-Oshima Island off the coast of Japan.  The circle was observed for a period of time, but it was unknown what actually made or caused the structure.  In 2011, the origin of the structure was discovered: a small male pufferfish, Torquigener sp., that was 120 mm long, was observed constructing a geometric circular structure.  After the discovery of this strange behavior of the male pufferfish, the structure’s function and the reasons for constructing a new structure for each reproductive cycle were investigated.

This study, done by Hiroshi Kawase, Yoji Okata and Kimiaki Ito, focused on ten male reproductive processes that were observed in two observation areas, one in Seisui and one in Katetsu, near the area that the first circular structure was found off the coast of Japan. The male pufferfish that were observed constructed a circular structure on the sandy seafloor that took between seven and nine days to complete.  The numbers of peaks and valleys within the structures were recorded along with the changes in the behavioral patterns of the pufferfish during the construction process.

a. Early Stage; b. Middle Stage; c. Final Stage; d. After Spawning.  Taken on June 23, 27, 29, and July 6, 2012, respectively.

            The early stage of construction consisted of the male creating a basic circular shape.  During the middle stage of construction the male pufferfish refined the circular structure.  In the final stage of construction, the structure was completed, and an irregular pattern of fine sand was organized in the central area of the structure.  Fragments of coral and shell were used to decorate the peaks of the valleys.  Females appeared only during the final stage of construction, and upon nearing the structure, the male would stir up the sand in the central area of the structure, retreat when the female entered the nest, then rush toward her several times.  After spawning took place, eggs were released in the central area of the nest. 

            The circular nests constructed by pufferfish exhibited three unique characteristics that have never been reported in fish:  radially aligned peaks and valleys created outside the nest site, shell and coral decorations on the peaks, and irregular patterns of fine sand particles in the nest site.  These three characteristics were maintained before mating but collapsed after spawning.  Therefore, it can be assumed that nest characteristics play an important role in the mate choice of the female pufferfish.  Definite factors affecting the females mate choice are unknown, such as size of structure, peak height, amount of fine sand particles, etc. 

a. Sand collected on the day before spawning; b. Sand collected on the day before hatching; White bar = 5mm

Although nest sites are usually retained, by fish and other animals, for the next reproductive cycle, new nest sites must be used by the pufferfish to create new circular nest structures for each reproductive cycle.  The valleys in the structure may not contain enough fine sand for multiple spawning cycles because one cycle consumes a large amount of fine sand particles.  A new site is needed to construct a new structure where there are sufficient fine sand particles available. 

The following video shows a male pufferfish constructing a nest: 

Resource

Role of Huge Geometric Circular Structures in the Reproduction of a Marine Pufferfish

White Sharks - Top Predator or Vulnerable Prey?

When we think of sharks, we generally think of big sharks, apex predators, the top of the food chain. But there is actually a small shark with a maximum length of  56 cm (or about 22 inches) that preys on marine predators over 10 times its own body length. It is called Isistuius brasiliensis or the Cookiecutter Shark.

Cookiecutter Shark size next to a pencil
en.wikipedia.org

It is known to attack and bite a wide variety of large animals including seals, whales, orcas, porpoises, pelagic fishes, sharks, and even a human swimmer. It is able to prey on large animals like this because it has a unique feeding strategy, dentition, tongue and mouth morphology. It uses this to scoop out a hemispherical plug of flesh from its prey.

Teeth and jaws of Cookiecutter Shark
australianmuseum.net.au

It is found throughout tropical and subtropical waters and it's range also extends as far south as New Zealand waters where its prey items could now include white sharks. A bite on a white shark from a Cookiecutter shark was observed. It has not been previously documented that a Cookiecutter shark would bite a white shark. There has been photographic evidence showing that they do indeed prey on white sharks. The bite wounds from Cookiecutter sharks are basically an oval bowl shape cut out of the flesh of their prey. Researchers think that they Cookiecutter shark comes in contact with the white shark when it moves to surface waters at night when it performs it's vertical migrations throughout the day.

Cookiecutter shark bite on a white shark
phenomena.nationalgeographic.com

Researchers think that the Cookiecutter shark may attract upward-looking predators using their ventral photophores (a light producing organ in some fishes) and a collar of pigmented cells posterior to the head as a lure. Because the bite on the shark is close to the mouth adds to that theory that the white shark was trying to eat the Cookiecutter and got bit then. Cookiecutters have been frequently reported to prey on beaked whales, sperm whales, some porpoises, and baleen whales. It is thought that this prey either represents less of a threat to the Cookiecutter or it provides a higher caloric content because of the higher blubber composition on marine mammals. Previously it was found that orcas suffer from bites from Cookiecutters. It is now known that two of the largest marine predators are victims to the Cookiecutter shark. White sharks are not as invincible as I once thought, and not only do they have to worry about parasites but also a fish that is less than two feet long taking a chunk out of them. I did not know that the Cookiecutter shark existed before this and it was really cool to learn that they prey on apex predators. 

Source: Hoyos-Padilla, Mauricio, Yannis P. Papastramatiou, et al. Observation of an attack by a Cookieshark     (Isistuius brasiliensis) on a White Shark (Carcharodon carcharias). 2013. Pacific Science 67, 1:129-   143.

The Precious Pearl

When most people think of a pearl, they think of a piece of jewelry, whether it is a bracelet, necklace, or a pair of earrings. Pearls are one of nature's best gifts to mankind and woman feel proud to wear them and show them off. But what people don’t think about is where these beautiful pearls come from and the other potential benefits they contain.

Pinctada is a genus of saltwater clams of marine bivalve molluscs, also known as the pearl oysters. These oysters have a strong inner shell layer composed of nacre, also known as "mother of pearl," which is an organic-inorganic composite material; it is what makes up the outer coating of pearls. It is strong, resilient, and iridescent. Although it may be thought that all oysters produce pearls, this is not quite the case. Pearl oysters are not closely related to either the edible oysters of the family Ostreidae, or the freshwater pearl mussels of the families Unionidae and Margaritiferidae. The various species of Pinctada produce different sizes and colors of pearls, depending on the size of the species of the oyster as well as the natural color of the nacre inside the shell.

A natural pearl begins its life inside an oyster's shell when an intruder, such as a grain of sand or bit of floating food, slips in between one of the two shells of the oyster. In order to protect itself from irritation, the oyster will cover the invader with layers of nacre and will continue to do so, layer upon layer. Over time, the irritant will be completely encased by the silky crystalline coatings. As a result, we are able to have the lovely gem called a pearl. Check out the video below for a better look at nacre and how it works:

How something so wondrous emerges from an oyster's way of protecting itself is such an amazing ability of nature. In addition to natural pearls, cultured pearls share the same properties. Oysters form cultured pearls in a similar way, the only difference being that a person carefully implants the irritant in the oyster, rather than leaving it to chance.

Besides being a gorgeous piece of jewelry, though, pearls have been found to contain traces of several metals and minerals which are known to have major health benefits! Pearls rich in essential minerals can help treat killer diseases like cancer. Pearls have been used for their medicinal value since their earliest discovery by man. Even today, the pharmaceutical industry continues to use pearls in medicine. Pearls that are of inferior quality and cannot be used in jewelry are those that are ground into a fine powder and used to prepare high-quality pharmaceutical calcium.

Studies have also been performed on pearls to better understand where their benefits come from. In a series of experiments by Ajai Sonkar (a scientist at the Pearl Aquaculture Research Foundation), pearls produced through special culture techniques were  found to contain traces of metal and minerals such as zinc, copper, magnesium, iron, calcium, sodium and potassium. He stated that “these micro-nutrients are essential for various body functions such as metabolism, growth and immunity. Of them, zinc has been found to be playing a major role in preventing fatal diseases like cancer.”

There have actually been numerous other studies performed with similar results, such as one published recently in the British Journal of Cancer which established zinc's anti-tumor role that prevents the growth of cancer cells. Other studies have found that zinc deficiency in the body causes delayed healing of wounds. Presently, Sonkar wants to carry out a comprehensive clinical test to find out health benefits of specially cultured pearls.

In conclusion, that pair of pearl earrings you’re wearing isn’t just your average piece of jewelry. It was created by a marine organism and contains numerous benefits besides being a sight to look at.  It’s amazing to think that in almost every culture, pearls could simply be worn as jewelry, or they could be ground up and made into potions and balms used to treat a wide variety of ailments and conditions. One legend said that a pearl placed in the navel could cure stomach disorders! The possibilities pearls posses are astounding and should definitely be noted.

Radiation: The Next Round!

The aftermath of the Japanese 2011 Tōhoku earthquake and tsunami still makes the news today. The Japanese Fukushima Daiichi nuclear power plant suffered a melt down after the disasters on the March 11, 2011. Environmental and public health concerns, and even government and corruption controversies surround the whole incident. All of which have validity. For the sake of science, this post will only focus on the most recent developments from the disaster that are affecting North Americans. 

Recently this moth, Canadian and U.S. scientists have detected radio active isotopes, cesium-134 and cesium-137, on the coast of Vancouver, British Columbia. The radioactive material has yet to reach the west coast of the U.S. according to Woods Hole ocean scientists. Isotopes are atoms of the same element that have different numbers of neutrons in their nuclei. For example cesium-134 has less neutrons than cesium-137. Cesium-137 has a half-life of 30 years and remains in the environment for several decades. The problem, at least right now, is cesium-134. It only has a half life of two years, but it is more toxic and can cause more problems than cesium 137. 

What makes cesium-134 bad? Currently, any detectable isotopes can be traced back to Fukushima. Surprisingly, cesium-137 has already been present in the atmosphere for decades. Besides Fukushima, sources of cesium-137 can be traced back to nuclear weapons testing overseas and all the way back to the Manhattan project. 

Scientists have been on the look out for radiation along the west coast since the wake of the disaster. All of the cesium-134 was concentrated in the upper 100m of the ocean according to the most recent tests. The results from the February 2014 sampling will be ready soon.  

Despite how scary this all sounds, it is still to early to tell how this will affect certain things. Also, the levels scientists are detecting are very minimal and are not high enough to cause any harm. The infamous Chernobyl disaster released 1000s of times more radiation than what is currently being detected. Currently, scientists are monitoring the Fukushima radiation closely and diligently. Just like the Bluewater Horizon disaster, the management of the Fukushima disaster is a giant science experiment because nothing like this has ever happened before. 

Fukushima's radiation reached coastal Canada first due to the Kuroshio Current. This is a powerful current that flows from Japan across the Pacific. In time, the current and the radiation it is carrying will flow downy he coast of North American and circle back toward Hawaii. This is however, only predictions based of models of the current. To this day, radioactive materials are still leaking into the water and are being carried across the ocean to North America. 

Article Source: http://local.msn.com/fukushimas-radioactive-ocean-water-arrives-at-west-coast

Sharks: A Deadly Misunderstanding

Zak Palmer

Every year people flock to beaches to get away from humdrum inland life and experience the tropical glory of the ocean. Most people are conscious of the creatures that inhabit these oceans, but in the case of the most sharks, it is for all the wrong reasons. People fear these magnificent creatures and do not understand the importance of their role in maintaining a healthy ocean. You can count the number of people that died from shark attacks last year on two hands. This hardly seems like something to be seriously concerned about as vastly more people die for much less feared reasons on a weekly basis.

Great white sharks are apex predators in the oceans. This means that they are the top predator responsible for controlling a variety of populations which, in turn, control other populations. If an apex predator is lost, then the entire ecosystem is thrown off. Populations that should be controlled grow wild and vastly decrease the numbers of the ones in which they feed. This causes the original population to die off as they run out of food. Health of the great white is vastly important as it has recently been discovered that they can live over 70 years which means they need longer to fully mature. The health of many oceans depends upon the great white.

The situation for the sharks is dire. Humans kill over 100 million sharks each year. Things such as bycatch, purposeful hunting, and accidents. These sharks that are purposefully killed almost never do anything to provoke their killers. It is estimated that over 90% of the predatory fish in the ocean have been eliminated by humans in the last 50-100 years. This number is alarming and contributes to unbalanced ecosystem and aids in the human destruction of oceans.

If the current trend continues, many shark species will be headed towards endangerment or extinction if they are not already there. Sharks currently represent the most threatened marine creatures on the World Conservation Union's red list. It is never a good thing when any species is lost, but it is especially detrimental when the species is of such vast importance.

All hope is not lost however. There are many things that can be done to save millions of sharks. Simple modifications to fishing gear or fishing techniques can save a huge amount of sharks lost from the fishing industry. A general knowledge of the creatures can lead to less deaths due to spiteful killings. A little extra attention when navigating the oceans can help to prevent accidents. As fascinating as sharks are it would be a shame to lose some of them for good. As humans, we need to stop trying to be the apex predators of the oceans and allow the creatures that were meant to be do their jobs. 

References:

Apex Predators

Shark Contribution to Oceanic Health

Shark Longetivity