Bubble, Bubble, Oceans in trouble

"Have you ever stopped to notice this crying earth, its weeping shores?"

Oceans cover 71% of Earth’s surface yet we know so much more about the terrestrial impacts of climate change than we do about the watery world which surrounds us. The oceans are the largest carbon storage units in the carbon cycle, with scientists from TeachOceanSciences predicting that oceans have absorbed roughly 1/3 of CO2 produced from human activity since 1800 and ½ of all CO2 produced from fossil fuels. However, whilst on the surface every thing may seem swell, if we dive into the deep end we see that the impacts of climate change are more threatening than Spielberg’s Jaws saga.

This article considers the impact of climate change on sea turtles, coral reef ecosystems and manatees.

Turtles in turmoil:

There are 7 different species of sea turtle, the Leatherback turtle being equivalent to a dinosaur which has surfed the waves of our oceans for centuries. Larry Crowder of Duke University stated that these turtles could be extinct in the next 10-20 years “unless sufficient international co-operation is mounted” to reverse the dramatic effects climate change is having on the species. But why are turtles so affected by climate change? Turtles, like other reptiles, have environmental sex determination- this means that the sex of hatchlings is determined by the temperature of their nesting sites. Studies have found that temperatures above 30oC favour female hatchlings, whilst temperatures below 30oC favour male hatchlings. As a result, turtles have adapted their nesting times to synchronise with times of the year where temperatures are likely to produce a largely balanced male:female ratio. Then we add climate change to the mixture. WWF states findings from the Intergovernmental Body on Climate Change that predicts that if we do not adhere to the desperate demands of the Convergence of the Parties 21 in Paris to keep temperature increase to a maximum of 1.5oC, then global temperatures will increase between 1.4oC-5.8OC by the end of the century. The turtle nesting synchronisation system will be sent into meltdown. It has been suggested that an increase of just 2oC will skew male:female sex ratios, add another Co2 on top, male turtle offspring would not stand the heat. The result would be catastrophic to the turtle.

Turtles in the “Scattered Islands”,in the Mozambique Channel, are already faced with this climate change catastrophe according to the National Geographic. Southern islands, like Europa, are cooler and therefore peak nesting times are in the summer, whereas in the warmer islands further north, like Mayotte, peak nesting is in the winter. Whilst temperature increases could see the Europa turtles shift their nesting times to the winter, the Mayotte island turtle’s nesting is already at the coolest time, they are faced with skewed sex ratios or forced migration from their habitual nesting zones; both choices see the turtle stuck between a rock and a hard place.

Climate change’s deadly talons do not end there for the turtle though; increased temperatures and rising sea levels will damage the food chain that sustains the turtle as a primary consumer. Sea turtles depend on sea-grass for the majority of their diet, but increased acidification of the sea through dissolving CO2 damages the sea-grass’ ability to absorb nutrients from the ocean floor, and rising water levels reduce its ability to photosynthesise. Subsequently, already 1/3 of all sea-grass has been destroyed, signalling another up stream struggle for the turtle. Rising temperatures also skew circulation patterns of ocean currents determined by the Coriolis effect; the result is that Crush and his turtle friends won’t be riding that ‘sweet East Australian Current’ to help find the Nemos of the future.

So the turtle is a fascinating, yet ultimately tragic, indicator of climate change; the pattern shows whilst climate change rockets, the sea turtle plummets.

Coral Reefs reeling from climate change:

Coral reef ecosystems (a community of living organisms interacting with other living organisms and their non living environment) are home to 25% of marine life, yet they cover just 1% of the ocean. Coral reefs are fragile ecosystems that are being fatally impacted by the impacts of climate change. The coral reef depends on a symbiotically mutual relationship with an algae known as zooxanthellae. Whilst the coral provides the zooxanthellae with shelter and compounds for photosynthesis, the coral is supplied with the by-products such as glucose and amino acids which are essential for it to convert into calcium carbonate to strengthen its skeletal frame. The zooxanthellae is also responsible for the kaleidoscope of colours in the coral reefs. However, when the coral becomes distressed, due to increased temperature or increased acidity, it expels this life sustaining algae resulting in coral bleaching causing the coral to adopt a deathlike pallor. If conditions return to optimal levels the zooxanthellae return and the coral will resurrect, however as the climate change clock is slow to wind back the coral is unable to sustain itself and dies. Richard Vevers, founder of the Ocean Agency, a non-profit Australian organisation assisting in the 50 Reefs project announced on March 3rd2017, where 50 reefs will be tested on how they could combat climate change, speaking to Reuters stated: “the latest bleaching has been the worst die off ever recorded.” WWF has stated that roughly ¼ of all coral reefs have been damaged beyond repair, and another 2/3 are under serious threat from increased temperatures which impairs their ability to fight disease and causes the expulsion of the zooxanthellae, as well as rising sea levels which reduces the ability of the zooxanthellae to photosynthesise, effectively the coral will drown in darkening seas. WWF predicts that coral reefs will disappear before 2050 if we make no significant effort to save them.

Acidification of the oceans is also having a devastating impact on the coral reefs. Coral reefs need a stable environment to flourish in, but climate change robs the coral of this stability due to the increased presence of CO2 lowering ocean pH levels which impacts their ability to absorb calcium carbonate to build strong structures. Scor 2009 released research which shows that the ocean pH has lowed by 0.11 units from 8.179 to 8.069, much closer to the acidic side of pH neutral, suggesting that the ocean is now 30% more acidic than in 1700. Whilst this may only seem minimal, don’t be so quick to forget it was the single straw which broke the camel’s back, translate that to the ocean and it is the CO2particle which collapses an ecosystem. The Royal Society in 2008 suggested that in 2100 if we do not take immediate, proactive and co-ordinated steps to lower the level of CO2 emissions the pH of the oceans will drop to 7.8, a level which would send coral reefs to the realm of fantasy, a watery wonderland long since lost.

Manatees face a morbid future:

Manatees live in shallow coastal areas and cannot survive in temperatures below 15oC. Manatees therefore might benefit from climate change if the result is increased temperatures in areas like Florida and Georgia, where there is an aggregation of manatees. But, climate change does not necessarily mean increased temperatures, consider the film 2012 where New York City froze into an icy wasteland…This means that manatees could be threatened if climate change flips the tropical paradise waters into freezing ice baths. Whilst warmer temperatures would be favourable for the manatees, climate change poses some more unique risks for their survival.

Manatees are affectionately known as sea cows, they spend their idyllic days munching on pastures of sea-grass. As has already been stated, rising sea levels will have a significant impact on the ability of underwater vegetation’s ability to photosynthesise, the result being a decline in the availability of the staple food source for the manatee. Rising sea levels will also cause salt water to infiltrate areas of fresh water where the manatees graze on non halophyte species of plants that cannot adapt to increased salinity; again causing further degradation in the simple diet that sustains the manatee. The result of rising sea levels will also encourage the building of sea defences such as groynes and sea walls to protect the ever encroaching coastal infrastructure. This means that the manatees will be forced to alter their lifestyles and will be forced to migrate further along the Atlantic or Gulf coasts. Whilst a change of scenery might sound pleasant, the forced eviction will push manatees out of coastal areas where there are designated manatee speed zones, to protect the manatees from collisions with boats which is a main cause of fatality. Savethemanatee.org states: “Manatees will face increased risks if they are forced to inhabit waterways which are lacking in safeguards for their protection.”

Climate change increases the likelihood of erratic freak weather conditions, such as hurricanes and storm surges. The storm surges can displace manatees, washing them into human settlements; scientists Langtimm and Beck in 2003 found that manatees suffer delayed health and reproductive issues as a result of the stress caused by the destructive weather conditions. Climate change will also increase rainfall causing increased nutrient run-off into warmer coastal waters, the prime conditions for “red tides”, caused by blooms of microscopic red algae known as Karenia Brevis. Karenia Brevis produces toxins which effect the nervous systems of mammals like manatees who graze on the algae, it left 44 dead in 2005.

So the manatees must migrate, starve or be blown on the crest of a wave into human settlements by storms; the future seems bleak unless climate change is halted.

Cry me an ocean:

WWF states that climate change is one of the major drivers that is causing the ocean to change more rapidly than at any other point in millions of years. Just focusing on the plight of three different species of sea-life out of a plethora of equally troubling pleas for help only highlights how much human activity is destroying its own home and how essential it is we act immediately and effectively to prevent the destruction from progressing to a point where we cannot resuscitate our oceans and the marine life it sustains.