Seals and Endocrine Disrupting Chemicals

Endocrine disrupting chemicals (EDCs) can have an impact on marine organisms that inhibit the planet. These chemicals mimic hormones or they can block them which will have a negative affect on the organism(1). When these hormone levels are altered, the messenger system can effect processes like reproduction, development or immune function(1).


Grey Seals, Horsey” by Jeremy Halls licensed by CC by 2.0

EDCs Found in Seals and Marine Habitats

Seals come in contact with EDCs via food and water. Below are some of the most common that seals come in contact with.

PCBs: or polychlorinated biphenyls were used widely in electrical equipment like capacitors and transformers. Although they have been banned or highly restricted these are still effecting our environment. They are soluble in fat so that is why this pollutant can stay in the the fat of mammals–like seals.  The route of exposure for PCBs in the general population is the consumption of contaminated foods, particularly meat, fish, poultry, even drinking water (2).

Phthalates: are found in a lot things that you and I may use daily. Items that may contain phthalates are shampoos, laundry detergent, food packaging, children toys,  hairspray, after shave and lotions.  These chemicals usually make it into run off water via landfill sites. Phthalates are also lipophilic (3).

Pesticides: DDT and other pesticides also have an impact on the seal population. They enter the ocean by run off via agriculture fields. Even though DDT was banned from the U.S. it is a lipopilic molecule that can stay around in fats for a while (4).

So What?

Persistent organochlorides like PCBs and DDT, are passed down to generations. If a pregnant seal passes this down to her fetus is can affect the development of the unborn pup.  After birth, these chemicals are then passed to the seal pup again via the milk from the mother.  In adult seals, when they eat contaminated prey, they are accumulating more EDcs in their body (5). There has been a strong correlation found between high PCB levels in the seal blubber and low reproductive rates. This would cause a reduction in the seal population in itself (5). Another study, conducted by B.M Backlin also found this to be true(6).


Seal Mom and Pup” by mafzail licensed by CC by 2.0

Stockholm University is doing research on the effects EDCs in humans and wildlife. This university has a few different projects going on that involve this research. One project is called the EDC-MixRisk. If you want to learn more about the research taken place at this university, please click here.


Want to learn more about Baltic seals? Please click here!!

If you want to learn about the seal population and EDCs, please click here!


1. “Endocrine Disruptors.” National Institutes of Health. U.S. Department of Health and Human Services, 05 Jan. 2017. Web. 02 May 2017. <;.

2. “Learn about Polychlorinated Biphenyls (PCBs).” EPA. Environmental Protection Agency, 13 Feb. 2017. Web. 02 May 2017. <;.

3. Center for Food Safety and Applied Nutrition. “Ingredients – Phthalates.” U S Food and Drug Administration Home Page. Center for Food Safety and Applied Nutrition, n.d. Web. 02 May 2017.

4. “DDT – A Brief History and Status.” EPA. Environmental Protection Agency, 22 Nov. 2016. Web. 02 May 2017. <;.

5. Lutter, Stephan. “Seals & Endocrine Disruptors.” (n.d.): n. pag. WWF. Web. 2 May 2017. <;.

6. Backlin, B.M, L. Eriksson, and M. OloVsson. “Histology of Uterine Leiomyoma and Occurrence in Relation to Reproductive Activity in the Baltic Gray Seal (Halichoerus Grypus).” Veterinary Pathology. N.p., 01 Mar. 2003. Web. 02 May 2017. <;.




Coral Mining

…Yes that is correct, coral can mined. Personally, I did not believe it when I was looking into this topic. But yes, coral mining is a threat the coral reefs around us. You are probably wondering, what is coral mining and what are the effects that come along with it, and I am here to tell you! Coral mining is when live corals are taken out of the water and are used for other purposes like bricks, road fill, or cement for new buildings. Corals are mined for new buildings because they contain limestone and they are also used for other construction material.  Dead corals can be mined for calcium supplements or harvested for souvenirs or jewelry; corals can also be harvested for marine aquarium industry. Corals are also being harvested for medical usage.  Researchers have been using coral for bone graph clinical trials.

How Do They Get The Coral?

The people who actually mine coral do it either one of two ways. They will either do it manually, or by using dynamite. If a worker is trying to annually mine coral they will ion bars and sledge hammers to break up the larger corals into more manageable ones to bring to shore, or to put on a boat. If they are using dynamite to mine the corals, they will blast the section they want which will break up the corals into smaller pieces so it can be brought to shore. This has a bigger effect on larger areas of the reef they pick.


jesse beazley’s reef- dynamited corals” by q phia licensed by CC by 2.0CC by 2.0

Impacts To The Reefs

The biggest effect of coral mining is that is causes a loss in biodiversity. By taking out chunks and rock from the reef, substrate is lost. Any coral polyps that come to the area cannot attach themselves to a structure thus the process is decreased. The reef won’t be able to grow larger in that area if coral polyps cannot become attached anywhere. Sedimentation occurs while the workers are mining the corals; the process of removing the corals causes disturbances to the sea floor and leave remnants behind.  Sedimentation can affect any of the benthic animals that reside here.

Coral reefs protect the land from storms and natural disasters. When a reef is partially removed or completely removed the shore becomes more vulnerable to storms and natural disasters. These effects can cause the land to retreat and impact the safety of any remaining parts of that reef section.  This will cause erosion. Locations around the world that have corals reefs are used for a source of food and tourism. The tourism industries have been negatively affected by mining. This is because for every ten dollars that is made from mining the community actually loses roughly two hundred and fifty four dollars.

Where Does It Happen?

Coral mining takes place anywhere coral is available, any locations hat have shallow water. Mining usually occurs at low tide when it is easier to gather coral. There are prominent locations for mining these includes The Barrier Reef, the Maldives, Panama, Indonesia, and East Africa.  Many of the reefs in these areas are protected under Marine Protected Areas now.


Coral reef in the maldives” by inka.cresswell licensed by CC by 2.0



Reef Distribution

Reef Formation

Fringing Reefs: Grow near the coastline around different islands and are separated from the shore by narrow shallow lagoons. These reefs are the most common reefs that are seen and are located in the tropics.

Barrier Reefs: These reefs are also parallel to the coastline but are separated by wider deeper lagoons. These reefs can reach the water surface creating a “barrier”.

Atolls: These types of reefs are rings of reef that create protected lagoons. These reefs are usually in the middle of the ocean. Atolls are usually formed when islands surrounded by a fringing reefs sink into the sea or the sea level rises around them (these islands are often the top of volcanoes).

Patch Reefs: are reefs that grow up from the bottom of the island, platform, or continental shelf. These types of reefs usually occur between fringing reefs and barrier reefs. These types of reefs vary greatly in size and do not touch the surface of the water.


Atoll forming” by Wikimedia Commons is licensed under CC by 2.0


Caribbean Coral Reefs

Caribbean coral reefs have a very unique collection of coral species. These include stony corals and many native species also. Some of these species are very high in commercial value. Most of the coral reefs  in the Caribbean Sea are fringing reefs. These reefs are very well developed and are located in a few different places like the coasts of Cuba, Jamaica, and the east coast of Andros Island in The Bahamas. The smaller islands also have fringing reefs that surround them. These islands include The Bahamas, Aruba, Bonaire, and the Cayman Islands. These reefs are shallower and provide some great Caribbean scuba diving and snorkeling opportunities. The Caribbean Sea also houses two “true” barrier reefs. The Belize reef is roughly 300 kilometers (186 miles!!). This is a section of the Mesoamerican Barrier reef system which is 900 kilometer (560 miles!!) long. Another barrier reef is located off the the east of Nicaragua. The Caribbean Sea has a very rich marine habitat more than any other in the Atlantic ocean. There are about 65 species of corals and 500-700 reef fish that live in these reefs!


Belize Aerial 16” by Heath Alseike licensed under CC by 2.0 

Red Sea Coral Reefs

These corals reefs are in the Indian Ocean! Fringing reefs are really common in this area. The fringing reefs platforms are nearly 5000 years old and the reef complex itself is 2,000 kilometers (1,240 miles!!!) of shoreline. Many of the reefs grow directly from the shore line. The most dominant and active coral in this complex is the Acropora and Porites. There are also many offshore reefs in the red sea. There is also atoll rings of coral ridges that rise from the ocean, red sea coral formation is the result of tectonic forces. There are no “true” barrier reefs in this region. The red sea has a lot of features that distinguish it from the other reefs.  The corals here have developed a high tolerance to extreme temperatures, salinity, and occasionally turbidity (this would be caused by a dust storm that is relevant in this area).


Porites Fragment” by Umijin licensed under CC by 2.0

Indo-Pacific Reefs

The Indo-Pacific Ocean is a huge area that covers almost half the Earth’s surface.  This region contains all three major types of reefs; Atolls, barrier, and fringing reefs. In this region there is a presence of an algal ridge. These are very rare in the caribbean region. The Indo-pacific reefs also often have extensive reef flats composed of consolidated coralline sands. This feature is rarely seen in the Caribbean region. The center of biodiversity for these reefs comes from the coral triangle.  The father a reef is from this triangle the less species it will have.


The shallow hard coral reefs of the Indo-Pacific provide the habitat for a panoply of tropical fish.” By ZEISS Camera Lenses licensed by CC by 2.0

Coral and Coral Reef Basics

What Are Corals?

Corals are close cousins to sea anemones and jellyfish, meaning they all belong to the same phylum of cnidarians. Corals and sea anemones both have the same structure of the polyp. The polyp is like a tin can open at just one end, this open end is the mouth and it is surround by tentacles. On these tentacles there are stinging cells on them called nematocysts.  These stinging cells allow for the coral polyp capture small organisms and inside the polyp body there are digestive and reproductive tissue.


Coral Polyp” by Wikimedia Commons under CC by 2.0


Types of Corals

Soft Corals: are soft, bendable and look like plants and trees. Soft corals do not have a hard skeleton. These corals have wood like cores made of calcium (spicules), for support and have fleshy rinds for protection. These types of corals are referred to as ahermatypes or non-reef building corals. These corals do not always have a relationship with zooxanthellae.


Dendronephthya” by  Alexander Semenov under CC by 2.0


Hard Corals: are the architectures of the coral reefs. they grow in colonies, and create skeletons out of calcium carbonate. Hard corals are hermatypes and are known as reef building corals. This type of coral needs zooxanthallea to survive.



Tube coral” by Jon Connell under CC by 2.0


What are Coral Reefs?


Maldives reef” by  Alexander Semenov under CC by 2.0

A coral reef begins when the coral polyp attaches itself to a rock on the sea floor. This one coral polyp then begins to dived or bud into thousands and thousands of clones of itself. This polyp calicles connect to one another and this then creates a colony that will act as one. As this colony grows over hundreds and thousands of years it will join with other colonies and become a reef. Corals that build reefs are know as  “hard” or “reef-building” corals. There are such thing as “soft corals“, these organisms are flexible and may resemble a plant or a tree.  The coral polyps that build reefs have a symbiotic relationship with zooxanthellae, which is a microscopic algae. Through this symbiotic relationship, both organisms are benefited. The zooxanthellae create energy through photosynthesis and the corals use that as food. The poylps offer shelter for the zooxanthella and also food-the waste product of the polyp is used as nutrients.

What do Corals Need to Survive?

Corals need 5 things to survive.

Sunlight: Corals grow in shallow water where the sunlight can reach them. The algae that lives inside of them, zooxanthella, need sunlight to survive so corals also need sunlight to survive.

Clear Water: Clear water is need for corals to survive because it lets the sunlight in. when the water is opaque the corals will not thrive.

Warm Water Temperature: Hard corals (reef building corals)  require warm water to survive. Corals general live in water temperature of 68-90°F

Clean Water: Corals are very sensitive to pollution and sediments that can be in the sea. Sediments can create cloudy water conditions which wont allow for sunlight to get through-this will harm the polyps.

Salt Water: Corals require a certain balance in the ratio to salt to water. this is why corals need salt water to survive.

How do Corals Reproduce?

Many coral reef species only reproduce one or twice a year, and can reproduces sexually or asexually.Most coral species spawn by releasing eggs and sperm into the water, but the period of spawning depends on the type of coral. When an egg and sperm meet they form a larva called planula. Planula can form by two different ways, either fertilized within the body of a polyp or fertilized outside the polyp, in the water. Fertilization of an egg within the body of the coral polyp happens when sperm is released through the mouth of another polyp. When the larva is matured enough the mother will spit it out via the mouth. If the egg and sperm are fertilized in the water, corals will eject large amounts of egg and sperm into the water, this is known as coral spawning. Millions and millions of eggs are released into the water simultaneously. This is an amazing act that the natural world does.

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Cauliflower coral spawning, French Frigate Shoals” by USFWS – Pacific Region under CC by 2.0








Cognitive Intelligence in Dogs

Most dog owners pride themselves on that they have the most intelligent dog. We all know and have seen dogs fetch a ball or stick, and bring it back, but they can also be responsive when they hear their name and carry out the usual commands such as, “paw,” “sit,” and “roll over.” Through extensive training, dogs can be trained and conditioned to follow such commands (1).

Dog intelligence is the ability of a dog to learn, think, and solve problems (3). Some dog breeds are especially known for their high intellectual abilities. Breeds such as the Border Collie are commended for being workaholics, hence why they are typically farm herding dogs. The German Shepherds are notoriously known as police dogs due to their strength, intelligence, their ability to be trained, and obedience. On the other hand, Golden Retrievers, which were primarily used as hunting dogs, are powerful, active, but friendly, devoted family. Different breeds of dogs can learn different commands at different paces, some easier commands, some harder commands (2). But how do we measure this level of intelligence in dogs? As well as, different dogs and dog breeds all learn differently. So how do we measure and compare that? Animal behaviorists, psychologists, and scientists have come to the conclusion that dogs have three different intelligences, as well as studied the relationship between response latency through multiple cognitive tasks (3).

Instinctive Intelligence

Instinctive intelligence is what the dog was bred for. For example, herding dogs, like the Border Collie were originally bred to herd animals like sheep. Border Collies have the ability to round up animals, keep them close to together, and guide them in the right direction. These are the type instincts that they are born with. Human guidance may be used minimally. Other examples of this include guard dogs, which are meant to watch over, retrievers are have the instinctive intelligence to fetch, and hound dogs have the instinct to track smells from animals, or other objects (3).

Adaptive Intelligence

Adaptive intelligence is how a dog can learn to do something for itself. This includes learning and benefiting from experience in the dogs environment. Adaptive intelligence varies in different breeds of dogs, but also can vary in different dogs within the same bred. For example all golden retrievers have the similar instinctive intelligences, yet their adaptive intelligence will differ. Some dogs will continue to make the same mistake over and over again, and never learn from it throughout their lifetime (3).

Working obedience intelligence

This is the third type of intelligence animal behaviorists and psychologists have pointed out. This is similar to the human’s ability to learn in school. This is based on what a dog can learn to do when instructed to. When a dog that responds to their owners commands, they are showing the most important aspect of dog intelligence, obedience. This is important because if dogs are not able understand and obey their owner’s commands, then they wouldn’t be capable of preforming the pragmatic commands that we value them for, thus we would have never been able to domesticate them (3).



(1) Arden, R., & Adams, M. J. (2016). A general intelligence factor in dogs. Intelligence, 5579-85. doi:10.1016/j.intell.2016.01.008

(2) Nippak, P. M., & Milgram, N. W. (2005). An investigation of the relationship between response latency across several cognitive tasks in the beagle dog. Progress In Neuro-Psychopharmacology & Biological Psychiatry, 29(3), 371-377. doi:10.1016/j.pnpbp.2004.12.003

(3) (n.d.). Canine Intelligence-Breed Does Matter. Retrieved November 27, 2016, from

Zebrafish as a Model Organism

Zebrafish as a Model Organism

Zebrafish, more scientifically known as Danio rerio is a tropical freshwater fish belonging to the minnow family (Cyprinidae), and is an the Cypriniformes order of ray-finned fish. Zebrafish can be identified by their five uniform, horizontal blue strips on the side of their bodies (1). Originally native to the Himalayan region around Asia, Zebrafish tend to live in shallow ponds and still water. Zebrafish grow to be relatively small, only growing to be the length of 6 centimeters, which is equivalent to be around 2.5 inches (2). A female Zebrafish have a huge research advantage for scientists; not only can the female lay up to 200 eggs per week, but the female Zebrafish develop their embryos on the outside of their bodies, in a transparent egg (1). Among several advantages, this makes it possible to observe the developing embryo in its natural environment.


Picture 1: Zebrafish swimming in a tank. You can clearly see the five blue strips down the side of the Zebrafish’s body.

In general, Zebrafish are great model organisms because of their short gestation period of 2-3 days, and with a generation time of 3 months, they can start reproducing just within 3 months of time, and can live on average up to 3.5 years. In addition, female can lay up to 200 eggs per week (1). Therefore a single female Zebrafish can reproduce hundreds and hundreds of offspring throughout their lifetime. As mentioned before, female embryos develop on the outside of their bodies in a transparent egg. Not only can we witness the development of the embryo through the clear chorion(2). This also allows researchers to easily introduce genetic mutations because their embryos can absorb chemical mutagens that have been added to their water. Due to the clear chorion, we will also be able to easily see the impact of the genetic mutations or drug treatments (4).

Krogh’s Principle and Zebrafish

Krogh’s principle state that “for such a large number of problems there will be some animal of choice, or a few such animals, on which it can be most conveniently studied.” Krogh’s principle is important to disciplines in biology such as the comparative method (neurobiology, comparative physiology and genetics). Zebrafish have genetic similarity to humans, all the proteins studied have a similar function in fish and mammals (3). This has allowed researchers to use genetic, molecular and physiological methods can be used to understand the fundamental physiological processes in all animals (3). Researchers have used Zebrafish as model organisms for CNS disorders such as anxiety, epilepsy, and brain cancer. The transparent embryos not only allow for researchers investigate developmental biology, but also allow them to easily witness the impact of a genetic mutation or a drug treatment. It also allows them to easily introduce or manipulate Zebrafish’s genes. This all relates back to Krogh’s principle because as a model organism, Zebrafish are able to help multiple disciplines of biology to be conveniently studied (4).

Research with Zebrafish

Research with the model organism Zebrafish has uncovered studies of brain circuitry, synaptic plasticity, and behavior. At UCL researchers studied Zebrafish’s neuroanatomical information to better understand circuitry established by the neurons. Mapping the neuroanatomical information of the Zebrafish will help researchers understand the circuits that drive behavior, among many other things.

At UCL, researchers are studying a Zebrafish’s genetic makeup to identify mutations in the Wnt pathway, which controls tissue and cell regeneration and proliferation, in the developing embryo to see how mutations in this pathway can alter brain and eye development. They have already found several mutations that could not be detected on a wild type background, and they will continue to identify mutations, and will ultimately reveal important gene networks that affect the Wnt pathway during brain development.


Picture 2: Transparent picture of a Zebrafish’s body. You can clearly see the vertebrate and eyes.

Also at UCL, they are also studying the structural and functional asymmetries in the nervous systems that are found throughout the animal kingdom. The brain specialization in one hemisphere to perform specific tasks, is believed to increase cognitive performance. However, brain asymmetries that have been compromised are linked to many neural disorders or diseases like schizophrenia, autism, and degenerative diseases. They are studying the asymmetry in Zebrafish, which will help our knowledge of the mechanisms of the development and functions of the asymmetry.


(1) M. (n.d.). ZF-HEALTH. Retrieved November 27, 2016, from

(2) H. (2016). Facts About the Zebrafish | The Fact Site. Retrieved November 27, 2016, from

(3) NC3Rs. (n.d.). Retrieved November 27, 2016, from

(4) (n.d.). Retrieved November 27, 2016, from,5035.1

Links to Research Labs:

Pictures:  by kamujp/ CC by  by Orgeon State University/ CC by