This is my last official post as part of my "Global Environmental Change" module assessment! It's been a thoroughly enjoyable experience, even though it was daunting to start with. I feel I've learnt more about marine pollution in the last few months than during the entirety of my degree.

The biggest challenge I faced was deciding exactly what to blog about for each post, purely because of the wealth of information out there. I aimed to be as varied as possible in my choice of topics, but plastic took the limelight as it is the single biggest threat to our oceans and thus warrants such attention. I also tried to include a range of academic and non-academic sources to make it more accessible and fun!

I hope you've enjoyed reading my blog, and that I have managed to raise awareness of our precious oceans!

I'll leave you with one of my favourite photos from my study abroad year in Western Australia. It looks devoid of life, but it's actually the opposite (think sea turtles and huge starfish!). It's such a beautiful and unspoilt part of the world, and I hope everything is done to preserve it!

Turquoise Bay, Exmouth, Western Australia (taken October 2013)


Advantages of Plastic

I'd like to flip the coin for this post... After all my plastic-bashing posts, I thought it was only fair to check out some of the advantages of plastic.

First a bit of history:

The first form of "plastic" was developed by Alexander Parkes, who introduced his invention at the Great International Exhibition in London in 1862. Known as Parkesine, the material was made from cellulose, which was able to be moulded when heated and set into shape once cooled (American Chemistry Council).
The invention of Bakelite by Leo Baekeland in 1907 is considered to be the pivotal point in the history of modern plastics, as it was the first to be created using fossil fuels. The material was made using phenol, a derivative of coal tar, and paved the way for the modern or synthetic plastics we are now all too familiar with (BBC News Magazine 2014).

Since then, synthetic plastics have developed into a multi-billion dollar industry employing 1.5 million people in the US alone (Department of Commerce), and forms part of the country's top three largest manufacturing industries (The Plastic Industry Trade Association), which brings me to its first advantage: it is has huge economic benefits.

Most of the other advantages of plastic is reflected in its characteristics. For example, it is easy and inexpensive to produce, it is strong, versatile, lightweight, biologically inert (non-reactive) and can act as both thermal and electrical insulators (American Chemistry Council). These properties make it suitable for a variety of applications, such as those within the construction and transport industries, as well as for packaging and scientific applications (History of Plastic).

I remember listening to Anya Hindmarch on Radio 4's Desert Island Discs a few years ago talk about plastic (BBC Radio 4). Her father worked in the plastic business and made his fortune from it. Years later, Anya founded her hugely successful eponymous handbag company and designed the much-copied "I'm not a plastic bag" tote [Figure 1] aimed at bringing attention to our overuse of plastic bags.
Figure 1. "I'm Not a Plastic Bag" by Anya Hindmarch (Vanity Fair, September 2009)

What I struck me most during the interview is that Anya said is that plastic is not bad, it's our misuse of it that is. And I couldn't agree more.


RAW for the Oceans

This is pretty cool:

Dutch fashion label G-Star Raw has collaborated with Bionic Yarn to create a line of demin and apparel made from plastic taken from the oceans [Figure 1]. Named RAW for the Oceans, the line is headed by the multi-talented Pharrell Williams, who is not only the Curator and Co-designer of the project, but is also the Creative Director of Bionic Yarn, the company that creates the specially devised yarn used to make the garments.

The interactive RAW for the Oceans website (click here) features videos and links aimed at raising awareness of the fragile state of our oceans and our responsibility to protect them.

Figure 1. ARC 3D tapered jeans for women by RAW for the Oceans. The garment is made from "the first Bionic Yarn denim" (RAW for the Oceans)

The yarn used to make the garments comes in two varieties, both of which comprise recycled PET plastic fibers [Figure 2]. HLX is composed of 40% of recycled PET plastic fibers with the rest made up of a core (which determines the strength and stretchability of the yarn) and an outer wrap that can be either natural of synthetic depending on the purpose of the yarn. The second yarn, DPX, is similar to HLX but doesn't contain a core so that it may be used for knit fabrics, not just woven ones.

Figure 2. The two yarns produced by Bionic Yarn: HLX (left) and DPX (right) (Bionic Yarn)

The process behind making the yarn is fascinating: plastic is taken from the oceans and is broken down into chips, which are then turned into fiber. This fiber is then spun into core yarn and is then wrapped with either an outer wrap (for HLX) or cotton (to create DPX). The new Bionic yarn is then weaved or knitted into fabrics used to make the garments (Bionic Yarn Manufacturing).

It's such a good idea and one I hope continues to develop and expand through the fashion world and beyond!


Noise Pollution

Now this one surprised me at first, as I had never come across it before. However, it appears that noise from ocean-based anthropogenic activities is having an effect on marine species. Indeed, both literature and non-academic sources list shipping, activities from the oil and gas industries and those from the military as the most common sources of noise pollution in our oceans (Weilgart 2007; International Fund for Animal Welfare).

Noise pollution in our oceans is of particular concern to cetaceans (whales, dolphins and porpoises) because they rely on their sense of sound more than any other sense (Weilgart 2007) for communication, navigation and the monitoring of their surroundings (Monterey Institute). Because noise travels a lot faster in water, it is has a far greater reach than it does when it travels through air (Smita 2001), suggesting that its effects can be felt by marine species even when they are not found in the vicinity of the point of origin. Suggested effects of noise pollution on cetaceans include disorientation, leading to stranding and moralities (Weilgart 2007).

However, ceteaceans may not be the only ones affected. A paper by Slabbekoorn et al. (2010) called for more studies to be carried out on the effects of increased marine noise on fishes. Although it is known that the hearing ranges of fishes do overlap with the frequencies of anthropogenic-induced marine noise [Figure 1], it is unsure what the ecological implications are of long-term exposure to such noises (Slabbekoorn et al. 2010).

Figure 1. The hearing ranges of a sample of fish species (red bars; from top: European eel, Atlantic cod and goldfish) and mammalian species (blue bars; from top: California sea lion, bottlenose dolphin and fin whale). The grey block represents the range of anthropogenic noise, while the three grey bars at the bottom indicate the range for low, mid and high-frequency sonar (Slabbekoorn et al. 2010)

Increases in noise levels in our oceans may be already having a detrimental effect on marine species, but it is only going to get worse with climate change. It appears that sound travels faster in warmer water. Whilst it is known that ocean acidification is a cause of the rise in atmospheric carbon dioxide, according to Hester et al. (2008), this will lead to noisier oceans as sea temperatures continue to rise!


Ending the year on a positive note!

Check out this awesome TED talk by Boyan Slat, founder of The Ocean Cleanup: he is such an inspiration, not just because of his age (18 years old!!), but for making an insurmountable task like cleaning up the oceans seem so possible, almost easy even! A great note to end the year, in my mind.

Happy New Year!!!



Continuing with plastic pollution, I wanted to bring your attention to macroplastics - and as you've probably guessed, these are simply larger pieces of plastic when compared to microplastics. Most authors refer to macroplastics as those that aren't microplastics i.e. anything bigger than between 1-5mm depending on the author (see my first post on microplastics), although Gregory and Andrady (2003) also include another class of plastics identified as mesoplastics. These include plastics such as virgin resin pellets. For the purpose of this post, I will consider macroplastics to be anything that can be seen with the naked eye. Examples include bottles and caps, cups, rope and beer can rings (Andrady 2011).

Much like microplastics, effects of macroplastics include ingestion and contamination. However, macroplastics also cause entanglement. Below is a review of these three effects:

1. Ingestion

The results of the ingestion of macroplastics are clearly seen in the Midway video in the first post [Figure 1]. Indeed, according to Rios et al. (2007), nearly half of all marine bird species are known to ingest plastic.
Animals consume plastic either directly, by mistaking it for prey, or indirectly when they consume prey that has ingested plastic. Among the problem associated with the ingestion of macroplastics are satiation and malnutrition, blockage of the intestine and internal wounding from sharp objects, all of which may be fatal to the animal (Gregory 2009).

Figure 1. Photo showing the stomach contents - most of it plastic -
of a decaying albatross found on Midway Atoll (Daily Telegraph Australia)

However, not all ingestion from macroplastics leads to death. Tomás et al. (2002) looked at 54 juvenile loggerhead turtles in the Mediterranean. They found that despite plastics accounting for 3/4 of all debris found and low feeding discrimination among the turtles, there was no clear evidence of intestine blockage or them dying because of plastic ingestion (Tomás et al. 2002).

2. Contamination

This is the same issue with microplastics (again see post below) - toxic compounds dissolved in the ocean may adsorb onto the surface of plastic and depending on the compound, may cause severe health issues, and may also make their way up through the food chain (Cole et al. 2011).

3. Entanglement

Figure 2. A selection of photos depicting various forms of entanglement; clockwise from top left: green sea turtle entangled in a gillnet (National Geographic); seal with a deep cut around its neck from a fishing line (BBC); turtle with a six-pack ring around its middle (Ocean Crusaders); another entanglement in a gillnet, but this time the victim is a grey whale (Oceana)

Turtles, some pinnipeds (seals, sea lions and fur seals), cetaceans and birds have all been affected by entanglement. This is usually due to the nets but can also be with smaller items such as bottle cap or six-pack rings [Figure 2 and references therein].
Entanglement causes limited movement and thus a reduction in how well the animal can travel and hunt/find food. This may lead to starvation and inability to feed their young (Gregory 2009).

I hope those images don't upset you too much, but I thought the best way to convey the gravity of marine pollution and the effects of entanglement was to approach it using photos. After all, an image is worth a thousand words...


Microplastics part 3: Effects

This is my final post on micrplastics and this time I'm looking into the two most significant effects and potential threats of these minute fragments of plastic:

1. Ingestion

One of the major potential threats of microplastics to marine fauna is ingestion. Figure 1 shows potential transport pathways of plastic particles, as well as their interaction with the biota (Wright et al. 2013).
Among the different methods of ingestion by aniamls, microplastics may be taken up either actively and passively. The former describes the voluntary selection of microplastics due to their similar appearance in both size and shape to the food normally consumed by the animal. Passive ingestion refers to indiscriminate feeding, whereby the animal doesn't differentiate between types of food. Animals may also ingest microplastics through scavenging or indirectly when they consume prey that had previously ingested plastic particles (ibid).
A study by Farrell and Nelson (2013) investigated the effectiveness of trophic transfer. The authors added 0.5μm fluorescent microspheres to water that contained mussels. Once the mussels had filtered these microspheres from the water, they were fed to crabs. The results showed the approximately 0.28% of microspheres that had been filtered by the mussels were transferred to the crabs (Farrell and Nelson 2013), demonstrating that there is evidence for trophic transfer.

Figure 1. Potential transport pathways of microplastics and their interaction with the biota (Wright et al. 2013)

However, some animals manage to avoid the ingestion of microplastics altogether. Interestingly, some bivalves have developed a way to sift through particles before ingesting them, and thus unlike passive feeders actually discriminate between these particles (Wright et al. 2013).

2. Contamination

Another threat is the contamination of toxic compounds from their adsorption to the surfaces of microplastics. Because of their small size, microplastics have a large surface area : volume ratio, indicating that they are more likely to adhere pollutants onto their surfaces (Cole et al. 2011). There have been a number of studies published on the types of chemicals found on micorplastics, including trace metals (such as chromium, lead and cadmium) (Holmes et al. 2012), brominated flame retardants (Engler 2012) and Persistent Organic Pollutants (POPs) including organic compounds such as organochlorine pesticides, Polychlorinated Biphenyl (PCBs) and Polycyclic Aromatic Hydrocarbons (PAHs) (Mato et al. 2011). The biggest concern about POPs is that they are known mutagens and/or carginogens and endocrine disruptors (Cole et al. 2011), which suggests that ingestion of these may cause problems, especially if there is significant transfer across the trophic level.

The sources and effects of microplastics are vast and complex, but hopefully I've provided with you with an informative overview over the last few posts. Next up - macroplastics!