The Great White shark, climate change and ocean carbon cycles

The latest media 'hysteria' about shark attack arises from a tragic fatal bite incident when WA teenager Laeticia Brouwer was mauled by a shark at the popular surf break - Kelp Beds - near Esperance (south coast of Western Australia) just before 4pm on Easter Monday (2017).

The paramedic who was first on the scene said the teenager suffered tremendous blood loss and couldn’t be saved despite quickly receiving first aid.

While sharks are relatively common in coastal waters, attacks are exceptional given the overwhelming presence and numbers of people in the surf zone. You are more likely to be killed in a road accident, riding a horse or a vending machine, than by a shark.

Federal Environment Minister Josh Frydenberg says WA isn’t doing enough to protect people from sharks urging shark culls and drum lines, according to the West Australian. "In light of the recent shark attack, the Commonwealth would welcome any proposal to protect human life first and foremost,” he said. “This could include the newest drum-line technology, shark exclusion nets, culling or other measures which WA sees fit.”

WA Fisheries Minister Dave Kelly has ruled out the idea of a shark cull in response, according to the ABC. "We're not going down the path of a cull because there's no evidence that it actually makes our beaches safer," he said, "...no evidence that that actually reduces the likelihood of future attacks," Kelly said.

Like on climate change, we are seeing the issue of shark conservation or culling being politicised rather than public education and options for shark incident mitigation. Our Federal Environment and Climate Change Minister should know better. The oceans are the domain of sharks and they have an important role to play as apex predators as part of the ocean carbon cycle. When we swim in the oceans we need to be mindful of the risks involved, including utilising the latest in public shark warning and repellent devices.

Mindless culling of sharks will not actually reduce the risk of shark attack without doing great harm to the ocean ecosystem trophic structure. It is as apex ocean predators that sharks do us the greatest service in maintaining the ocean carbon cycle and help keep carbon sequestered in coastal sea areas (Blue Carbon) to help us mitigate climate change.

Seagrass carbon Storage - marine biosequestration could be important for negative emissions

Updated 28 October.

Blue carbon is part of the solution to tackle climate change. So why aren't we talking about it far more?

Blue carbon refers to the carbon sequestration potential of coastal ecosystems: that zone reaching from just above the high tide mark to the coastal shallows. It includes salt marsh, mangroves and seagrass meadow ecosystems.

We need to take care and nurture our coastal ecosystems as they can play a vital role in bio-sequestration of carbon at rates far in excess of forests and soil carbon farming.

Biologists working with seagrasses met to present papers and discuss scientific practices at the 12th International Seagrass Biology Workshop (ISBW) (Conference website) in Wales 16th to 21st October. Just before the conference 122 scientists across 28 countries associated with the World Seagrass Association released a statement on the global importance of conserving and expanding seagrass meadows.

Guest Post: Stopping mangrove deforestation in Indonesia could help slow climate change

Coastal wetlands are important carbon sinks, all too often ignored as important ecosystems for preserving and indeed fostering and growing, for mitigation of climate change. In January 2013 I looked at how Mangrove forests threatened by Climate Change in the Sundarbans of Bangladesh and India. In December 2013 I featured a guest post on Philippines steps up restoration of mangroves as defence against typhoons, tsunamis, sea level rise. Read more of my posts on blue carbon. Research has shown that Mangroves among the most carbon-rich forests in the tropics (Donato etal 2011).

Now a new study published in Nature Climate Change identifies the importance of preserving the extensive mangrove forests remaining in Indonesia for reducing it's greenhouse gas emissions.

Seagrass projected to drastically decline with sea level rise

To most of us, what is hidden beneath the waves of our coastal environment remains invisible and is little thought about or cared about. Yet seagrass meadows, though hidden from our direct view, contribute valuable ecological services supporting valuable fish nurseries, as food for dugongs and turtles, and as a highly efficient blue carbon sink sequestering carbon.

A new study of the seagrass meadows in Moreton Bay, Queensland found that a significant proportion of valuable seagrass habitats would be lost without action to offset the affects of climate change. "The area of seagrass habitat was predicted to decline by 17% by 2100 under a scenario of SLR of 1.1 m." said the study.

Lead author Dr Megan Saunders from UQ's Global Change Institute said "Seagrass meadows not only help to slow climate change by sucking up a large portion of the world's plant-stored carbon, but they also benefit livelihoods, food security, fisheries, biodiversity, shoreline protection and other ecosystem services,"

Coastal Wetlands under threat from Sea Level Rise says World Bank

Climate change induced sea level rise of one metre is likely to destroy 60 per cent of the developing world's wetlands says a new World Bank research working paper. The economic loss of these wetlands is estimated at approximately $630 million US dollars per year.

The World Bank study looked at the risk to coastal wetlands in 76 countries at a sea level rise of one metre. Because there are so many uncertainties with the rate of sea level rise, the one metre level was chosen to study the likely impact. This sea level may be achieved this century, with sea level rising 60% faster than IPCC projections. Sea level rise is unstoppable, but it can be slowed through emissions reduction and give us humans and ecosystems a chance to adapt. Sea levels will continue to rise for several centuries.

The study found that about 99% of the coastal wetlands at elevations of one meter or less in the Middle East and North Africa could disappear, as well as 77% in sub-Saharan Africa, 66% in East Asia and 39% in Latin America and the Caribbean. Places like the iconic Sundarbans of Bangladesh and India, a major home and refuge to the Bengal tiger, are under threat.

Planners need to allow for Coastal wetlands migration due to sea level rise, climate change

Coastal Wetlands are under pressure. They face rising seas from climate change, but their biggest obstacle to migrate naturally inland is human development with roads, houses and other infrastructure blocking their way. And our urban planners are largely unaware of this tricky situation.

We all love to live beside the sea, but coastal urban development and rising seas will increasingly threaten sensitive coastal wetlands with no room to move and imperilling the survival of their unique plants, birds and fish.

Our urban planners have taken a stable sea level for granted with development to date, often destroying wetland environments for coastal development, agriculture and aquaculture.

More recent urban planning incorporating sea level rise predictions places an emphasis on the threat to peoples houses, roads, railway embankments and other human infrastructure. But planning also needs to encompass the coastal wetland environments that share our coastlines. These ecosystems will also need to migrate inland as the ocean rises.

See also: Mangrove Alliance | Mangrove Action Project | Mangrove Watch Australia | Coastal ecosystems suffer 100 fold decrease in capacity to store carbon mitigating climate change

Mangrove forests threatened by Climate Change in the Sundarbans of Bangladesh and India

A new study has found the Sundarban coast retreating up to 200 metres in a single year due to rapidly deteriorating health of the world's largest Mangrove forest in the Sundarbans, the Ganges delta region of India and Bangladesh.

Zoological Society of London (ZSL) researcher Dr Nathalie Pettorelli, senior author of the paper says: "Our results indicate a rapidly retreating coastline that cannot be accounted for by the regular dynamics of the Sundarbans. Degradation is happening fast, weakening this natural shield for India and Bangladesh."

In the Bengali language 'Sundarban' can be literally translated as 'beautiful forest'. The area is the largest block of continuous mangrove forest in the world, being home to almost 500 species of reptile, fish, bird and mammals, including the endangered Bengal tiger.

See Also: Mangrove Alliance | Mangrove Action Project | Mangrove Watch Australia | Planners need to allow for Coastal wetlands migration due to sea level rise, climate change

Seagrass meadows are key carbon sinks for combatting climate change

May 22 is UNESCO's
 International Day for Biological Diversity which focussed strongly on conserving our marine diversity. One of the important marine ecosystems are the seagrass meadows around the coasts of the world. A new global scientific research study just released has shown that seagrass meadows store significantly more carbon than any land based forest. They are very important as carbon sinks. But they are also suffering a major decline due to pollution from agricultural and mining development and chemical runoff, coastal development changing water turbidity upsetting photosynthesis in seagrass, and increasing sea surface temperatures affecting seagrass growth due to global warming.

The new global study of seagrass meadow ecosystems has found that coastal seagrass beds store much more carbon than can be stored in even the most carbon dense forests, such as the temperate native forests of Victoria. Seagrass meadows can store up to 83,000 metric tons of carbon per square kilometre, mostly in the soils below them. In comparison, a typical land forest stores around 30,000 metric tons per square kilometre mostly as wood. It is the first global study to analyze the carbon storage capacity in seagrasses.

Seagrass meadows support a highly level of biodiversity with many fish species using the seagrass during their juvenile period, as well as providing homes for crabs, sea urchin, seahorses shrimp and prawns. Sea tutles, dugongs and manatees depend on seagrass meadows as a primary food source. As Professor Carlos Duarte points out in an article on The Conversation website, Indigenous cultures new the significance and value of seagrass meadows. Conservation and restoration of seagrass ecosystems provides a unique Submarine Carbon Tax Opportunity! Seagrass meadows are intense, but fragile carbon sinks.

More Information: Seagrass Watch | Global Seagrass Monitoring Network

Coastal ecosystems suffer 100 fold decrease in capacity to store carbon mitigating climate change

The carbon sink capacity of urbanized river estuary and coastal environments to mitigate climate change has reduced by 100 fold according to scientists from the University of Technology Sydney. The Scientists used core samples from Botany Bay in Sydney to reconstruct the sedimentation changes in the past 6000 years, highlighting the changes in the ecology. The plant samples in the sedimentation changed as rapid industrialisation occurred around Botany Bay during the 1950s.

"We have effectively gone back in time and monitored carbon capture and storage by coastal ecosystems, finding a 100-fold weakening in the ability of coastal ecosystems to sequester carbon since the time of European settlement. This severely hampered the ability of nature to reset the planet's thermostat." said Dr. Peter Macreadie, University of Technology, Sydney Chancellor's Postdoctoral Research Fellow.