Moving away from the ocean focus from the past two weeks, todays post explores a recent article by the BBC about the identification of a new wild cat in Brazil by Coles (2013).
Everyday I look on Nature and there is an article about a new species being discovered. These new species are found in a range of locations from Burma to closer to home in the United Kingdom. With new species being discovered everyday, is it possible to make the judgement that biodiversity is possibly increasing on local scales around the world?
Check out the Coles (2013) article and make up your own judgements. It is important to note that we do not know everything about the natural world and therefore to make all encompassing conclusions about global biodiversity, is extremely difficult. These conclusions are strictly based on the knowledge we do have while accepting the unknown.
Articles to check out:
New species of Hammerhead shark discovered off Carolina coast (Kenniff, 2013)
Spectacular New Species Found in the Lost World (Dell'Amore, 2013).
New Species of 'Skeleton Shrimp' discovered (Vincent, 2013).
Being an ecology enthusiast with a particular fondness for corals, todays post is one of my favourites so far. We all acknowledge that coral reef ecosystems are extremely important to the health of the oceans. While they cover only 1% of the oceans, it is estimated that one quarter of all marine biodiversity spends, at least part of their life on a coral reef. When corals are mentioned most people think of tropical waters and an instant picture of the Great Barrier Reef pops into mind. To me the term 'coral' automatically conjures up brightly coloured images present in the Pixar film, Finding Nemo.
However, as the NOAA state shallow water corals are only one type. There are cold water corals and deep sea corals that have limited light producing soft corals.
What are corals?
The Oxford English Dictionary defines corals as ' hard stony substance secreted by certain marine coelenterates as an external skeleton, typically forming large reefs in warm seas'.
Corals are invertebrate animals belonging to a group called the Cnidaria. They can exhibit a wide range of colours, shapes and come in all sizes. Each coral is made up of hermatypic polyps and most live in colonies. A coral colony can grow to be very large indeed. The hermatypic polyps produce calcium carbonate to form calyx (NOAA, 2011). The calcium carbonate adds to the coral skeleton forming the beginnings of the coral structure. Corals develop slowly over millions of years, today the corals you see have been growing for around 50 million years. To date there are around 800 known species of hard coral and more being discovered, just as new species of marine animals are being found in the most remote ocean locations every day.
Coral reefs are found throughout the oceans, from deep, cold waters to the shallow tropical waters of the Indian Ocean. Tropical reefs extend from 30 degrees North and South of the equator. However, cold corals can also be found in places closer to home such as off the West coast of Scotland and Ireland. Cold water reefs have also been found in the Mediterranean.
There are various factors that cause the pattern of coral reefs throughout the world. These include: The role of ocean temperature The effects of emersion Bathymetry Levels of sedimentation
Types of Coral Reef
Fringing Reef: most common type of coral reef located close to land.
Barrier Reef: looks like a fringing reef, however, it is located further away from the shore. They are separated from the shore by a band of water.
Atoll: large ring shaped reef, which create a lagoon in the middle.
Anthropogenic threats to coral reefs Corals are ecosystems that have been developing for years, and in this time have been subjected to natural change. The worry now is that with increasing human stresses, corals may not be able to cope. WWF (2010) states that already 'one quarter of coral reefs are subjected to damage beyond repair, with another two thirds under threat'. With reef building corals representing a critical component for marine biodiversity, it becomes important to conserve these ecosystems in order to conserve the species that use coral environments (Huang and Roy, 2013).
Destructive fishing practices: Blast, dynamic fishing and bottom trawling are types of fishing practices that cause devastation to sensitive coral reefs. Bottom trawling has been widespreadsince the 1980s. The large rubber tires on the nets can damage the coral structures. Dynamic fishing is where explosives are set off underwater destroying coral. This has been particularly a problem in South East Asia (Cadwell and Fox, 2006).
Pollution: Urban and industrial waste being released into the oceans which are poisoning the reefs. Pollutants increase the amount of nitrogen in the waters causing an overgrowth of algae, which can smother the reefs, concealing them from sunlight which the polyps need to survive (McManus, 2000).
Sedimentation: Anthropogenic coastal construction, mining, logging and tourism developments can cause erosion. This erosion causes increased levels of sediment being produced. Sediment covers coral, almost suffocating it and causing the corals to produce a protective mucus (MES, 2002). This process takes incredible amounts of energy and if corals are overworked they can die.
Ocean acidification: As mentioned in my previous post, marine environments are particularly threatened by climate change and the increasing pH of ocean waters. Since the beginning of the industrial revolution, the oceans have been absorbing increasing amounts of excess carbon dioxide. With ocean acidification, corals cannot absorb the calcium carbonate needed to maintain their structures and therefore the reef will dissolve (SCOR, 2009).
Ocean acidification effects on coral reefs.
Global warming and coral bleaching: In the Anthropocene, global warming is a known threat to many ecosystems. It occurs because carbon dioxide and other greenhouse gases cause a blanket, preventing heat from the sun to escape, warming the atmosphere. Ocean warming is extremely devastating to coral biodiversity, which is sensitive to changes in temperature. If oceans stay warm for several weeks, zooplankton leave the corals, turning them white in the process, because it is the zooplankton that gives corals their unique colours. NOAA (2013) discussed how in 2005, the USA lost half of its coral reefs in the Caribbean in only one year due to a huge coral bleaching disaster.
Coral Bleaching: showing the distinctive white coral.
However, a recent study showed it is not all bad news. Elevated nitrogen and phosphorous at a study site in Florida Keys from 2009-2012, showed coral bleaching. What this study also noted was that once the injection of pollutants ceased, the corals became able to recover and in a surprisingly short period of time (PhysOrg, 2013).
There are other threats to corals, however I have rambled on too much already. I hope you enjoy this post and it provides a insight into the marine biome and the anthropogenic impacts of coral ecosystems. Being a corals fanatic, I find it extremely worrying that humans can be having such disastrous effects to one of the world's most beautiful environments. I, for one, want to be able to dive and explore these unique ecosystems, enjoy their bright colours and extraordinary patterns and it would be devastating if these environments were not there for people to enjoy.
In previous posts I have concentrated on mainly terrestrial biodiversity (however not on purpose). Today I take a swim with the fishes to investigate one of Earth's most interesting biomes- the ocean.
'The ocean covers nearly three quarters of the Earth's surface, provides about half of the oxygen we breathe and feeds billions of people every year'(Le Roux, 2013).
The oceans have been protecting the Earth from the worst effects of human induced climate change for years by absorbing excess carbon dioxide (Bijma et al. 2013). This absorption, however, is having a negative effect driving the oceans into an acidic state. Along side this acidification, ocean warming is having grave impacts on the structure of many marine ecosystems. Bijma et al.(2013) coined ocean warming, acidification and deoxygenation the 'deadly trio' of anthropogenic impacts that are causing accelerated loss of marine populations (Worm et al. 2006). Since the industrial revolution the world's oceans have become 26% more acidic and will continue to force oceans into a acidified state at an unprecedented rate.
Ocean acidification is the reduction in the pH of the ocean waters by the uptake of carbon dioxide from the Earth's atmosphere. It can also be caused by chemical pollution into the oceans. The carbon dioxide dissolves in the seawater generating changes in seawater chemistry. The addition of carbon dioxide increases the concentration of bicarbonate ions and carbonate ions which, consequently lowers the pH making oceans more acidic. For a beginners insight into ocean acidification take a look at the below flow chart, showing the changes in chemistry from slight alkaline to acidified seawater.
Beginners guide to ocean acidification.
Many recent reports, have discussed how ocean change may be faster than any time in the last 300 million years, predicting that by 2100 there will have been a 170% increase in ocean acidity. But is it all doom and gloom for oceans? There has in fact, been scientists that have discussed how marine species could survive and even thrive (seagrass) under ocean acidification and warming (McGrath, 2013).
What environmental scientists are most worried about is the effect of the 'deadly trio' on corals. In the Great Barrier Reef half of the coral cover has been lost over the past 27 years. There have also been dramatic coral bleaching events in 1998 and 2002 due to anthropogenic ocean warming. In the Southern Ocean, we can unfortunately already see corrosion of pteropods (sea snails) shells. In my next post, I aim to expand on corals in more detail, focusing on the threats posed by the anthropocene to these highly sensitive environments.
Coral Disaster: Great Barrier Reef coral bleaching. Source.
With a carbon release of around 30 gigatonnes of carbon dioxide a year, it is no surprise that academics are worried about a major ocean extinction. As I touched upon in my previous post a sixth mass extinction' is a upcoming worry. However, speculative this theory may be, oceans are one of the biomes which are most vulnerable to a huge biodiversity decline. With changing ocean conditions, many species could possibly find themselves in unsuitable environments, especially in oxygen poor "dead zones"(Le Roux, 2013).
What will the future hold for the oceans? Will there be a biodiversity loss in one of the worlds most diverse environments? Keep your eyes peeled for my next post which will look at the threats posed to corals.
