Just hangin' out

G'day,

I feel that it would be helpful (and perhaps I should have posted this earlier on) to provide a global distribution map of coral reefs so that you can see where they are. Introducing ArcGIS' very own...

The purple denotes the global distribution of coral reefs (2003) whilst the pink denotes the global distribution of cold coral reefs (2005). 

I have been scanning the net trying to find a useful map depicting the coral distribution of the past but I have come up with nothing (or nothing that is good). Therefore, I will use some brief examples of selected areas that have undergone change. 

The Coral Reefs of Eilat by Yossi Loya (2000)

Eilat is a coastal town located in the Gulf of Eliat, nestled between Egypt and Saudi Arabia. This paper by Yossi Loya provides a brief review of the past 35 years of study related to coral species diversity and structure at Eilat. The changes observed have been due to many reasons including natural disturbances (extreme midday low tides), man made perturbations (oil spills) and man's destructive activities (eutrophication). For example, monitoring of the coral community structure at the 'Japanese Gardens' site has revealed that the percentage living cover of stony corals decreased by 75% over the past 15 years and the number of coral colonies by 73%. This has been a direct result of eutrophication only. With the addition of all other known impacts, both natural and anthropogenic, the situation in this location is deeply concerning, as over recent years coral mortality has increased markedly and diversity has drastically decreased. 

Coral Reefs of Indonesia: Past, Present and Future by Anugerah Nontji (1999)

The location and nature of Indonesia makes it a prime spot for coral reefs to grow. There has been a long history of coral reef studies in this region, initially by Rumphius (1705) and then later on by Dutch scientists in the early 1900s with a second wave in the 1960s. This continued research over the centuries shows the importance of coral reefs to this nation. According to Tomascik et al. (1997) the coral reef area of Indonesia is approximately 85,700 km² (14% of the world's total) and the reef biodiversity is the greatest in the world (Rosen, 1971). The Indonesian reefs are susceptible to a number of natural and anthropogenic impacts. This is reflected by the decay in the current conditions of the reefs. Data taken from a paper by Moosa and Suharsono (1997) highlights the significant changes that have occurred over time. The 324 sites indicate that more than 70% of the reefs are either fair or badly damaged whilst only 6.48% are regarded as being in excellent condition. This means that coral coverage is worrying as categories bad to fair denote cover of 0-50% whilst excellent equates to 75-100%. 

So what!?

So, the big picture is worrying. Despite each example being thousands of miles apart, the issues they have faced and continue to face are extremely similar. Furthermore, as a result of these issues, the impact on reef abundance and diversity follow a similar trend. Therefore, it can be assumed (but not with 100% certainty) that the majority of other coral reefs have been impacted in the same way. Thus, if one had the opportunity to work in reverse and create a map of coral distribution for the past based on the information in the papers, then the distribution would most probably be greater. 

Until next time,

Seb 

Why Coral Polyps and Zooxanthellae Matter! Part 2

Let's continue with the next two categories!

2a. Environmentally, reefs provide coastal protection. It is calculated that coral reefs protect approximately 150,000 km of shoreline across 100 countries (Burke et al., 2011). Their ability to provide this service is dependent on the size of the reef and their surface roughness coefficient. The reef acts to buffer wave energy and prevents waves attenuating directly on shore thereby limiting coastal erosion and the morphology of the beach (Lugo-Fernandez et al., 1998a; Sheppard et al., 2005). This benefit is particularly apparent in low-lying atolls such as the Maldives, which would not exist without their fringing reefs. Importantly, this role is becoming ever more important due to the increased frequency in storm events.

2b. Coral reefs provide a water filtration service. Most species are filter feeders and in doing so, consume suspended particulates in the water column. This ability is determined by the presence of flagellated collar-cells or if you want to be fancy, choanocytes. As a result, the near shore waters are better in terms of quality and clarity (reefrelief.org, 2012). I think that this is a pretty interesting role but at present, I can’t find any more literature. Come on Metalib, find something relevant!

3. Coral reefs are used for medicinal purposes. The NOAA (2006) states that they are the ‘medicine cabinets’ of the 21^st century. Medical researchers, to develop pharmaceuticals have harnessed the complex chemical compounds developed by many reef species, such as venoms. The U.S. Commission on Ocean Policy (2004) provides some examples of reef related compounds used to treat cancer and HIV amongst others. More specifically, Glaser and Mayer (2009) provide a more specific, yet equally interesting example for cancer that highlights the importance of reefs. They illustrate how scientists managed to synthesize an anti-cancer agent from the Caribbean sea squirt species for the treatment of ovarian cancer. This role that coral reefs play cannot be understated. Since only 5% of the world’s oceans have been explored and a small proportion of reef life sampled, there is the potential for a whole load of new pharmaceutically valuable discoveries (Nature.org, 2011). Further, it is important that change for the better starts now. We do not want to lose pharmaceutically significant species that we haven’t even discovered yet! To see more coral related pharmaceutical treatments, click here. 

It seems that sea squirt, whilst being pharmaceutically beneficial, looks as bad as it tastes. Though the tuna eyeballs look tasty... nom nom nom. 

I hope that you can now appreciate the importance of coral reefs and why they are so interesting. 

Until next time, 

Seb 

Why Coral Polyps and Zooxanthellae Matter! Part 1

Are we enthused and ready to go? I am. If you're not, here's a video to get you going!

So you may be wondering what coral polyps and zooxanthellae are? Well they are just the constituents that make up a coral reef. In fact, thousands of coral polyps make up a coral colony. Coral polyps have a symbiotic relationship with the microscopic algae, zooxanthellae, with the latter residing in the polyps providing a greater ability to fix food, nutrients and oxygen for the coral colony as a whole. Further, they give the polyps their amazing colours. So the title was just me trying to be clever...

Anyway, there are many reasons why reefs matter! First and foremost, coral reefs are one of THE most productive and biologically rich ecosystems on earth. Whilst they spread over 250,000 sq km of the ocean, which roughly equates to less than 1/10^th of 1% of the marine environment (for you budding mathematicians out there…that’s 0.001%), reefs are home to 25% of all know marine species (McAllister, 1995). Importantly, reefs support more species per unit area than any other marine environment. This includes 4,000 coral reef fish species and 800 species of hard corals amongst hundreds of other species that form complex food webs (Paulay, 1997). Whilst coral reefs are dynamic environments that are an important habitat for many species, they also provide numerous ecosystem services that millions of people globally depend on (Burke et al., 2011). These can be broken down into three categories…

1a. Coral reefs provide substantial socioeconomic benefits. According to Burke et al. (2011), 850 million people live within 100 km of a coral reef (fig. 1) and as a consequence, a high proportion of these people are likely to derive some benefits from the reefs. Coral reefs are even more important for those 250 million people that live within 30 km of reefs (fig. 1), many of which who reside in developing countries or island nations. For these populations, reef associated species provide an important source of protein that equates to, on average, one quarter of total fish catch in developing countries. Lastly, coral reefs have great potential. A healthy, well-managed reef could yield between 5 and 15 tons of fish per sq km per year (Jennings and Polunin, 1995; Newton et al., 2007). This is significant in terms of a subsistence livelihood as well as economically, through export. For example, whilst coral reefs play an important cultural role in American Samoa, they supply over 50% of fish caught for food (NOAA, 2001).

1b. Coral reefs form the backbone of local economies through tourism. They are crucial for sustained and stable tourism interests in many tropical regions. After experiencing the beautiful reefs along the coast of the Red Sea, one can truly appreciate the integral role reefs play in a country’s tourism strategy. The coral reefs provide not only excellent sites in terms of diving and snorkeling but they also benefit other businesses such as restaurants and the like. Burke et al. (2011) identifies clearly the importance of coral reefs; approximately 200 countries benefit from tourism related to reefs and moreover, tourism contributes more than 30% of export revenue in 20 of these countries (The World Bank, 2010; UN World Tourism Organization, 2010). Consequently, there is no doubting the importance that reefs play in terms of food and livelihoods.

Fear not, I haven't forgotten about the other two categories, they will come later this week. If I put it all in one then it will be a bit of a brain overload and you will probably get bored. 

Until next time, 

Seb

Let's have some background!

To aid understanding of the future posts on this blog, I feel that it is important to familiarise you with the Anthropocene and the debate around it. In 2002, the Nobel Prize-winning chemist, Paul Crutzen proposed the term 'Anthropocene' to denote the current interval of anthropogenic influence in global environmental change (Crutzen, 2002). Zalasiewicz (2008) stated that this influence was primarily through increased human population and economic development. Crutzen (2002) has suggested that the Anthropocene represents a new geological epoch from 1800 AD onwards based on analyses of trapped air in polar ice cores that highlighted the significant change in the global atmospheric composition of carbon dioxide (CO₂) and methane (CH₄). These increases can be accredited to the industrialization of the developed world and Crutzen (2002) notes that this date coincides with the production of the steam engine in 1784. 

However, there is much debate surrounding this hypothesis. The debate over the beginnings of the Anthropocene is centered on the ‘early anthropogenic hypothesis’ that was proposed by William Ruddiman in 2003. Whilst Crutzen (2002) stated that the Anthropocene began from around 1800 AD, Ruddiman (2003) presented a comprehensive set of evidence that pointed towards human modification from as early as 8000 years ago. This modification is identified through the variations in CO₂ and CH₄ concentrations, driven by Earth-orbital changes, in the atmosphere since the start of the Holocene. Here is a diagram that illustrates this for CO₂ from Ruddiman (2003)...

So what does the Anthropocene have to do with coral? Well, due to the substantial impact of anthropogenic influence on the Earth since the original hypothesis of the Anthropocene started in 1800 AD, it has resulted in distinct stratigraphic signatures (which are used to formalized a new geological epoch) such as novel geochemical, biotic and sedimentary change (Zalasiewicz, 2008). The key impact on coral results from distinct changes in the composition of the atmosphere. As of September 2012, the concentration of CO₂ was 391 ppm, which equates to a level 40% greater than preindustrial concentrations, whilst CH₄ concentrations have doubled (Steffan et al., 2007). As a consequence of this dramatic change in atmospheric composition, the global temperature by the end of the century could match those of the Tertiary, being 1.1 °C to 6.4 °C greater than the current level (IPCC, 2007). Over the course of the past two hundred years, the modification of ocean temperature has resulted in biotic and geochemical change. In terms of coral, this is fundamental. Bellwood et al. (2004) states that the shallow ocean environment has become particularly vulnerable due to ocean acidification, bleaching and a whole load of other factors that are and aren't related to climate change, that have caused a reduction in diversity and abundance of coral.

Oh, abrupt ending, but I've got to stop there otherwise I will get carried away. The next instalment will focus on the importance of coral. 

(P.S. That coral seahorse on the last post was a cartoon. I knew it was too good to be true!)

 

Welcome to Under the Sea!

Hello there,

I never thought I would ever write a blog (especially on coral), but I have been given the opportunity to do so, so why not! Plus, coral fungi are becoming all the rage in gastronomy. 

Moving on, whilst I am may be late to the party on the blog front, issues related to coral are a hot topic suffering from a nightmare hangover caused by that crazy kid climate change, and it is going to take more than the routine hangover remedy (N.B. berocca, alka-seltzer and paracetamol) to cure it!

As such, this blog intends to inform, explain and amaze you, in relation to topics to do with coral and climate. The broad themes will cover The Anthropocene, coral history and uses, climate change impacts and lastly, solutions to counter these. These will all be supported by what every Geographer loves to hear... case studies!

Here's a picture for you...

Yes, it is a seahorse.

Please check back soon!