Crashing Waves

Crashing Waves

Thursday 24 September 2015

Sea God's Cup!





Hello! Today I'll be talking about an interesting find that happened right here in the waters of Singapore! Drum roll~~ Introducing the Neptune's Cup Sponge! This sponge was thought to be extinct since 1908 where the 2 specimens of the sponge was collected in West Java. Subsequently, the sponge has been identified after being dredged up in 1990 giving people hope that a wild population might still exist somewhere. it is not until 2011 that a live specimen of the sponge was found in Singapore's waters.

In the past, it is said that these sponges were extremely common is the waters round Singapore, so much so that they were a commonly used for a variety of purposes, such as bathtubs for children. Yes, they do grow pretty big!

A photo showing child bathing in a dried Neptune's Cup Sponge
(Lim, Tun & Goh, 2012)
The 2 specimens were found around the waters of Sister island, one of Singapore's few protected areas for wildlife. The rediscovery of the species, with 2 specimens in relatively close proximity, gives researches hope that there is a healthy wild populations of the sponges that they have not found.Little is known about the sponge, with scientist still debating if it does indeed belong in the genus Cliona. As such, live specimens, of which the only known 2 are the ones mention above, are extremely valuable to researchers wishing to study the sponge and its various aspects.

The rediscovery of the sponge, although a big news, was not highlighted upon much upon its initial discovery, perhaps it is best to keep it that way. This is as Singapore still has poaching activities present in its water. It would be a logical line of thought, that keeping the location of the sponges vague and not highlighting its presence to possible poaches, is part of a plan to protect the species. After all, Neptune's Cup Sponge is known to be sought after by collectors because of its unique shape and it is said to be the most well known sponge species in the world. Though there is speculation of a wild population, that may not necessarily be true. It is possible, that may have just found the last remaining survivors of the entire species. As such, it is important that we keep them protected. Cheers!

Neptune's Cup Sponge at Sister Island
References

Lim, S., Tun, K., & Goh, E. (2012). Rediscovery of the  Neptune's Cup Sponge in Singapore: Cliona OR Poterion?, 49-56. Retrieved from: http://www.tmsi.nus.edu.sg/files/05_Lim_Pg%2049-56.pdf
Last accessed: 24 September 2015

Platt, J. (2015). Amazing Neptune's Cup Sponge Rediscovered in Singapore. Blogs.scientificamerican.com. Retrieved from: http://blogs.scientificamerican.com/extinction-countdown/amazing-neptunes-cup-sponge-rediscovered-singapore/
Last accessed: 24 September 2015

Sister Island Marine Park,. (2015). [The Neptune's Cup sponge (Cliona patera), long thought to be extinct here, was rediscovered off St John’s Island in 2011.] Retrieved from: http://www.straitstimes.com/singapore/environment/5-things-about-the-sisters-islands-singapores-first-marine-park
Last accessed: 24 September 2015

Saturday 19 September 2015

Survivor: Java



Unlike all the other survivor game shows, this show will probably give the prize money to the individual that manages to raise the number of participants. Introducing the Javan Rhino, Rhinoceros sondaicus.

The Javan Rhino's last wild habitat is the Ujung Kulon National Park, where all 60 individuals are said to live. In the past, there used to be 2 other subspecies of Javan Rhinoceros that live in Borneo and Vietnam. Today the Javan Rhino is the sole surviving subspecies still present in the wild.

Only males of the Javan Rhinoceros species grow the horn above its nose

Javan Rhinoceros grow to about 1.7m in height and 4m in length, having lose folds of skin giving them an armour-like appearance. Its single namesake horn grows to about 25cm atop the male's nose, it is used to plow away vegetation and uproot plants for them to eat. Due to the similarities Javan Rhinoceros was once mistaken to be of the same species as the Indian Rhinoceros due to their similar appearances, it is now noted that the species is a smaller relative of the Indian Rhinoceros.

As mentioned in the previous post on cheetahs, the Javan rhinoceros face the same problem of a small population, their genetic variability his been severely affected by large extinctions within their populations. Such events include those outside the sphere of human influence, for example, the Karkatoa volcanic explosion of 1883 which wiped out majority of the then Ujung Kulon Javan Rhinoceros population. The current population now present in the park is said to be a re-colonization of the species from other parts of Java.

However, even in light of its current crisis, the Javan Rhinoceros population shows that it is still fighting for its species survival. This ray of hope comes in the form of, much to conservationist's delight, 3 healthy looking calves - 2 males and 1 female!


Three new Javan rhino calves roam through an Indonesian national park
One of the 3 new Rhino calves with its mother
Yet this is only the first of many steps to a successful recovery of the population. The population needs to grow bigger and establish itself in areas other than the park to prevent further loss of genetic material, or face a possible sudden extinction like what happen in 1883. There is still along way to go, but for now, let us celebrate this small victory.

References

Belcher, S. (2015). [Partially Submerged Javan Rhinoceros Photograph]
Retrieved from: http://www.rhinos.org/species/javan-rhino/
Last accessed: 19 Sept 2015

Fernando, P., Polet, G., Foead, N., Ng, L., Pastorini, J., & Melnick, D. (2006). Genetic diversity, phylogeny and conservation of the Javan rhinoceros (Rhinoceros sondaicus). Conservation Genetics, 7(3), 439-448. http://dx.doi.org/10.1007/s10592-006-9139-4
Retrieved from: http://www.rhinoresourcecenter.com/pdf_files/124/1245662536.pdf
Last accessed: 19 Sept 2015

Getty Images,. (2015). [Javan Rhinoceros Mother and Calf]
Retrieved from: http://www.telegraph.co.uk/news/earth/wildlife/11859454/High-hopes-for-the-worlds-rarest-rhino-after-three-calves-are-spotted-in-Indonesian-national-park.html
Last accessed: 19 Sept 2015

Purnomo, H., Herawati, H., & Santoso, H. (2011). Indicators for assessing Indonesia’s Javan rhino National Park vulnerability to climate change. Mitig Adapt Strateg Glob Change, 16(7), 733-747. http://dx.doi.org/10.1007/s11027-011-9291-0
Retrieved from: http://link.springer.com.libproxy1.nus.edu.sg/article/10.1007/s11027-011-9291-0/fulltext.html
Last accessed: 19 Sept 2015

World Wildlife Fund,. (2015). Rare Video of Critically Endangered Javan Rhinos.
Retrieved from: http://www.worldwildlife.org/stories/rare-video-of-critically-endangered-javan-rhinos
Last accessed: 19 Sept 2015

Wwf.panda.org,. (2015). Javan rhinoceros
Retrieved from: http://wwf.panda.org/what_we_do/endangered_species/rhinoceros/asian_rhinos/javan_rhinoceros/
Last accessed: 19 Sept 2015

Sunday 13 September 2015

A cheetah can change its spots!

Pardon the pun, but yes it is true! The common saying about not being able to change spots has been defied, once again, by the animal kingdom. Though I do not think what you have in mind is the same thing - I am referring to the process of grafting!

Cheetahs (Acinonyx jubatus) are the fastest land animals, running up to 120 km/h in short bursts to bring down prey. They are also the last surviving species of the genus Acinonyx, the rest of the genus was said to have died in the late Pleistocene. This includes at least 4 other species in the genus and other Acinonyx jubatus subspecies. It is likely that the same extinction event caused a bottleneck effect. This meant that only a small number of the original population survived, leading to a huge lost in the genetic variability. Things only got worse for the cheetahs, genetically speaking. As surviving population multiplied, it led to inbreeding within the population. The inbreeding process caused severe impacts on the subsequent generations of cheetahs through high infant mortality rates . As such the population becomes smaller and smaller, even without taking into account external negative forces such as habitat destruction. This, in turn, made it more likely for inbreeding to occur as the cheetahs become more interrelated.

Cheetahs suffer from high infant mortality rates, making it difficult for population to expand

So then what has this have to do about changing spots and grafting? It is precisely because the above mention situation, individuals of species have become so genetically similar, and are able to accept skin grafts from each other. An experiment was conducted by O'Brien in 1983, where 7 unrelated cheetah pairs were given each others' skin as grafts, 6 were non-related and 1 was a pair of siblings. The results was that none of the grafts were rapidly rejected by its host, with majority of the grafts, 11 out of 14, being accepted without any rejection of sorts.

Further studies by O'Brien inquires about how similar are the cheetahs genetically and the results showed 0 polymorphism in the genes and a slight degree of polymorphism in the proteins. Though there are other animals that survive with low polymorphism, such as the polar bear, such low levels of polymorphism are not naturally found in anywhere else in the feline family.
Being so similar to each other does not give a species an advantage, in fact, it makes them more vulnerable to single selection pressure such as disease, that might cause its extinction, as the population does not have required variation to adapt.

Even as the idiom sheds a negative light on leopards not being able to change their spots- perhaps it is better not being able to after all.

References


O'Brien, S. (1994). The Cheetah's Conservation Controversy. Conservation Biology, 8(4), 1153-1155. doi:10.1046/j.1523-1739.1994.08041153.x
Last accessed: 13 Sept 2015

O'Brien, S., Roelke, M., Marker, L., Newman, A., Winkler, C., & Meltzer, D. et al. (1985). Genetic basis for species vulnerability in the cheetah. Science, 227(4693), 1428-1434. doi:10.1126/science.2983425
Last accessed: 13 Sept 2015

O'Brien, S., Wildt, D., Goldman, D., Merril, C., & Bush, M. (1983). The Cheetah Is Depauperate in Genetic Variation. Science, 221(4609), 459-462. doi:10.1126/science.221.4609.459
Retrieved from: 
Last accessed: 13 Sept 2015

The Zookeeper (2013) Cheetah-cubs
Retrieved from: http://www.babyanimalzoo.com/best-of-the-zoos-recent-batch/cheetah-cubs
Last accessed: 13 Sept 2015




Friday 4 September 2015

Jelly Blooms

In case you have not figured it out yet, today's post will be talking about jellyfishes! I have always been curious about jellyfishes, where they come from and how they multiply. In this posts, hopefully you will learn something new about jellyfishes!

Jellyfishes housed at the South East Asian Aquarium
Jellyfishes have two different forms in life, the polyps and the medusa. The medusa are more commonly recognized as jellyfishes, an umbrella like head with many tentacles streaming along after it as it bobs through the water. The polyps are a hidden side of the jellyfish life cycle many are oblivious about. In fact, how a jellyfish begins its life is as a polyp!

Life Cycle of a Jellyfish
Polyps, also known as scyphistomas, are small structures that fix themselves onto hard surfaces. Scyphistomas are usually found on the ocean floor, meaning they are benthic, and have tentacles to help it trap food and feed. These polyps then start to feed and mature and even multiply. Polyps were able to multiply through the formation of podocyst, these are able to bud off from one another developing into new polyps. This means that they reproduce asexually and the two polyps are genetically similar. Once matured, polyps can then start producing ephyras, which will mature into medusas, adult jellyfishes, within a matter of weeks. The process at which the polyp constricts itself to release the ephyras is known as strobilation. A single polyp can stobilate multiple times and is estimated to produce up to 15 ephyras per month. After strobilation, polyps will resume their daily business of eating and growing. 

Adult jellyfishes then go through the familiar process of sexual reproduction via external fertilization of the eggs. These eggs develop into larva and attach themselves onto hard surfaces, eventually, growing into polyps!

Jellyfish Bloom off the Coasts of New Zealand
In recent years, there have been reports of various increase in populations of jellyfishes. Cause of this phenomenon come from a variety of possible factors, all of which seemingly leading back to human interference with the ecosystem.
From introduction of an invasive species of jellyfish into a ecosystem, to less competition for food due to over-fishing, and even eutrophication of the water, leading to conditions that favor the growth of jellyfishes. These high populations of jellyfishes adversely affect the ecosystem through uncontrolled predation of the lower trophic levels. This also means that less fish will be present in the waters and thus destroy fishing grounds, affecting the supply of fish to the market. Beaches that the blooms occur at will also have to be closed down for the safety of the swimmers, affecting the economy of the area.

For a surprisingly transparent entity, it still holds many mysteries regarding its growth. This is especially true for the polyp phase of the life cycle. Thus, to understand how to prevent such blooms from getting out of hand, is essential to that scientist continue to study the jellyfish.

References

Deretsky, Z. (2010). Life cycle of a jellyfish. [diagram]
Retrieved from: 
Last accessed 5 Sept 2015

[Digital photograph of jellyfish bloom]
Last accessed 5 Sept 2015

Mills, C. (2001). Jellyfish blooms: are populations increasing globally in response to changing ocean conditions?. Hydrobiologia, 451, pp.55-68.

Last accessed 5 Sept 2015

Schiariti, A., Kawahara, M., Uye, S. and Mianzan, H. (2008). Life cycle of the jellyfish Lychnorhiza lucerna (Scyphozoa: Rhizostomeae). Marine Biology, 156(1), pp.1-12.
Retrieved from: 
Last accessed 5 Sept 2015

Whitetaker, J., King, R. and Knott, D. (2015). SCDNR - Jelly fish. [online] 
Last accessed 5 Sept 2015