Friday, January 19, 2018

Sea Turtles and Climate Change

"Hot chicks, cool dudes," is the saying that helps us remember that warmer temperatures are likely to produce more females in a nest of reptile eggs. Anjani Ganase, marine scientist, considers the conservation of sea turtles in the face of changing climate. (First published in Tobago Newsday, January 18, 2018)

Although my career as a marine scientist is still in its infancy, I have managed to witness substantial declines in coral reef ecosystems over the past ten years. While surveying some of these reefs frequented by other megafauna, such as manta rays and turtles, it made me wonder how these long-lived ocean residents, dependent on these ecosystems, were dealing with the rapid changes that have been occurring over the last thirty years. Sea turtles in particular, are an ancient species living in the present-day marine world. They have been around for about 100 million years (humans have only been here for about 200,000 years), having survived the last mass extinction event, 65 million years ago, and have also been through significant temperature and sea level shifts (Hamann et al 2007; Hawkes et al 2009). With future predictions of a rapidly warming climate on top of man-made stressors such as habitat loss and pollution, there is concern that these long-lived creatures may not now adapt quickly enough (Hawkes et al 2009).
 
A curious loggerhead turtle approaches the camera during a survey of the far north Great Barrier Reef. Photo by Anjani Ganase
Most of what we can anticipate for turtles in the future (given our rapidly changing climate) is based on knowledge of the nesting routines of the turtles. However, less is known about their routines between nesting seasons when they are foraging or migrating across oceans. Foraging and migratory patterns of sea turtles vary considerably among species, as well as geographically. Leatherback turtles travel the open ocean often to colder waters, feeding mainly on jellyfish; while the green turtles stay within the tropics and forage on sea grass beds and coral reefs neighbouring their nesting beaches (Hawkes et al 2009). How the food sources and ecosystems on which these turtles rely will fare under the changing climate may be a useful indicator of the health and survival of turtle populations.

Warming temperatures

If you were born after 1985, you have only ever experienced a hotter than average planet (compared to the previous 100 years; IPCC 2013; Roon 2015). The same goes for sea turtles. However, sea turtles are far more sensitive to temperature. While our gender is determined by our chromosomes/genes, the sex of most reptiles - including marine turtles - is determined by the temperature the eggs are exposed to while they develop. Higher temperatures produce female marine turtles, while eggs in cooler temperatures produce males. Eggs only successfully develop within a narrow temperature range; and indeed, may not thrive at all if the temperature is too low or too high. Sea turtle nesting is therefore largely limited to beaches in the tropics and sub-tropics where the conditions are most suitable for success. Numerous studies have predicted shifts in the sex ratio of turtle hatchlings to more females due to the predicted increasing global temperatures. A recent study has revealed that a remote tropical location in the northern Great Barrier Reef (Raine Island and Moulter Cay) has already been producing mostly (99%) female hatchlings for the past two decades because of the above average temperatures (Jensen et al 2018). This shift towards predominantly female offspring brings concern over the number of males available to mate. Along the east coast of Australia, Green turtles nest in the summer typically at locations that have incubating temperatures between 25 – 33 degrees Celsius (Hamann et al 2007). Unfortunately, a further increase in temperature by more than 2 degrees (by 2050) may push the incubating temperatures of these nests beyond the survival limits of the turtle eggs (Hamann et al 2007). However, there are other factors that influence the incubation temperatures (including specific traits of the beach, such as its grain size, sand colour, ventilation, precipitation and shading of the nests) which can result in geographical variations. While some beaches such as those in the northern Great Barrier Reef may produce predominantly female offspring, this may not be true for all beaches.

With a warming climate, there is also a potential for shifts in the timing of the nesting season or to other locations, which may allow turtles to compensate for the observed warming effect. Such shifts have been observed in the past with specific sea turtle populations (Hamann et al 2007). Warmer waters may trigger females to begin nesting earlier in the season, or to choose different nesting sites (Hamann et al 2007). However, such changes in nesting patterns may depend on the particular sea turtle species as some species tend to be more faithful to their nesting sites than others.


Sea-level rise

The rate of sea-level rise over the last century has been increasing at a rate of 3.2 mm/ year between 1993 – 2010 (IPCC 2013). This may not sound like much but a higher sea-level will affect low-lying coastal areas. This poses a problem for turtle nesting habitats that occur on sandy beaches along the coast, especially in areas where a natural inland migration of beach isn’t possible because of fixed infrastructure. As a result, the area of viable nesting locations becomes significantly reduced because of rising water tables that inundate nests with salt water, thus drowning the eggs or washing them away (Hawkes et al 2009). Currently, coastal cities globally are spending millions of dollars protecting properties by relocating sand or building bluffs and embankments to reinforce foundations. Such concrete structures further reduce the available natural sandy habitats for nesting.

Although these are trends that have occurred in specific locations and might be expected to occur elsewhere, there are numerous other factors that influence the survival and successful reproduction of a turtle. These additional factors; including the topography of the beach, its vegetation and even precipitation may buffer or exacerbate the changing conditions. The combined effects of these factors are likely to result in significant geographical variations in turtle nesting habitats.

We are now living in a time when humans have altered the climate and made substantial modifications to landscapes and ecosystems; and man and nature are experiencing unprecedented changes in our planet as a result. The survival of sea turtles is dependent on the availability of new and varied nesting sites and the adaptability of turtle behaviour, in seeking new nesting grounds within their biological framework, as well as changes in our behaviours. Trinidad and Tobago is home to many turtle species that nest on our beaches and feed on our reefs, sea grass beds and other nearshore habitat. In light of current scientific findings and the predictions for turtle populations, conservation efforts need to consider the rapid changes that may occur. How will our beaches and our local climate change with warming temperatures and rising sea levels? What measures can we take to ensure that suitable habitats – nesting sites – are available for future generations of sea turtles?

Acknowledgements: Special thanks to Dr. Michelle Cazabon-Mannette for her input and feedback.

References:
Hamann, Mark, Colin J. Limpus, and Mark A. Read. "Vulnerability of marine reptiles in the Great Barrier Reef to climate change." (2007).

Hawkes, L. A., et al. "Investigating the potential impacts of climate change on a marine turtle population." Global Change Biology 13.5 (2007): 923-932.

Jensen, M. P., Allen, C. D., Eguchi, T., Bell, I. P., LaCasella, E. L., Hilton, W. A., ... & Dutton, P. H. (2018). Environmental Warming and Feminization of One of the Largest Sea Turtle Populations in the World. Current Biology, 28(1), 154-159.
IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Roon, R. B. Let’s call it: 30 years of above average temperatures means the climate has changed (2015), https://theconversation.com/lets-call-it-30-years-of-above-average-temperatures-means-the-climate-has-changed-36175




Friday, January 12, 2018

Island Connections to the Pacific

From her University of Queensland base in Brisbane Australia, Anjani Ganase, marine scientist, visits islands in the South Pacific and finds familiar island traits with her Caribbean home.

Just off the east coast of Australia, lies Vanuatu, 83 islands in the south western Pacific with a culture vastly different from that of Australian neighbours. There, I found similarities with Caribbean culture and ecosystem that resonated with me. Their island culture is also well-blended with indigenous and colonial influences and has become its own identity.

The islands of Vanuatu occupy about 680,000 km2 of the south-western Pacific region. Their official languages include English and French, but there are over a hundred languages spoken across different islands and communities and the dominant creole language throughout the islands is Bislama. A blend of English and indigenous languages of Vanuatu, Bislama has morphed grammatically into a distinctive form. This language permits communication across villages and with foreigners, mainly Australians.  It is almost too familiar to the Caribbean ear, having a similar colonial root. A term like ‘pikinini’, reminds me of “pickney’; both mean child and both are reflective of the harsh colonial history. Other similarities between the Caribbean and Vanuatu include the local music, where local songs have reggae feel or even a groovy soca vibe made solely from the twangs of the guitar; and of course having a Digicel top up sign on every corner! The similarities between Vanuatu and the Caribbean do not stop here.

People of Tanna in the South Pacific Vanuatu island chain: displaying the uses of local plants in their traditional way of life. Photo by Anjani Ganase


Tanna Island, Vanuatu
Tanna is one of the southern islands of Vanuatu. This island has minimal permanent infrastructure: a few resorts, the main town, the central market and the road connecting them that runs along the western side of the island. The rest of the island is left to nature; roads that cross over the middle of the island are paved in ash and black sand. Fog, rain and the lush forest can close in on you and prevent you from venturing on your own. Trees and bush quickly bar roadways and paths where traffic wanes. During the hurricane season when visitors are few, we felt as if we were discovering untouched rainforest areas, secret landscapes hidden behind the forest canopy. Mount Yasur, the island’s resident volcano, and a guiding beacon for sailors in the southwest Pacific shapes Tanna’s natural landscape and culture. At night, we are guided by the ever-present glow of the volcano, which orients the locals living in the dark. There is no need for streetlights or neon lit signs. Instead, there are stars for entertainment, and story telling and silence, with perhaps the faint blare of music from a passing bus. Tanna homes are simple. Beautiful bungalows are woven from bamboo and palm leaves, often nestled under giant banyan trees and surrounded by ornate gardens beautifully laid out with ginger lilies and bougainvillea. On our day of exploration, we were shown, by the people of Tanna, how the forest, the rocks and the earth are all integrated in the their way of life. Leaves of one tree stacked one on top the other can be used to lift the weight of an injured person; while the roots of another tree (kava) is used in rituals and social gatherings, where the effects are relaxing and soothing.
A snorkeler swims through a gap in the reef flat that is teeming with corals. Photo by Anjani Ganase

Taking a peek underwater at Tanna’s coral reefs, I was also surprised to see a few reefs still rich in coral life, considering that in recent years there were a series of disturbances. In March 2015, Vanuatu was hit by a category five cyclone Pam, which passed less than 20 km off the west coast of Tanna, where their more sheltered reefs are located. In the summer of 2015-2016, an ENSO (El Niño Southern Oscillation) event on top of an already warming climate triggered what turned out to be part of the third global mass-bleaching event: many Pacific islands, including Vanuatu were put on coral bleaching alert for persistent periods of higher than average sea surface temperatures (https://coralreefwatch.noaa.gov/vs/gauges/vanuatu.php). Coral bleaching in the region was reported in several areas, including the Great Barrier Reef and American Samoa. It was clear that these reefs of Tanna were not affected as badly as the other reefs may have been. Although the reefs were not pristine, mass death from bleaching did not stand out. In fact, what was reflected were two years of recovery after cyclone damage, with coral recovery seen in many smaller colonies of branching communities, growing on the reef flat and crest, while the larger boulder colonies appeared to be little affected. Unfortunately, I couldn’t ignore another similarity with the Caribbean, Tanna reefs are also heavily overfished. Considering that cyclone Pam destroyed much of Tanna’s already delicate infrastructure, it was comforting to see resilience both above and below the water.

Small-island nations like Vanuatu in the Pacific and Trinidad and Tobago in the Caribbean will be the first to experience the effects of climate change, which will indeed spark necessary future changes. I wonder whether the decisions we make will be similar, and I hope that they will be for the better.
In the shadow of the volcano: a young boy plays in the sand at the base of Mount Yasur, Tanna Island, Vanuatu. Photo by Anjani Ganase
Branching corals grow in sheltered pools on the reef flat on Tanna Island, Vanuatu. Photo by Anjani Ganase



Friday, January 5, 2018

The Zero Waste Challenge

Tobago's iconic locations are well-kept and tidy; cleaned overnight, ready for visitors every morning. But do you know where the trash goes?
Do you think you can live so lightly that you generate no waste? Take the Zero Waste Challenge and find out how far you have to go to Zero.
Like all challenges of this nature, it asks us to consider the process of approaching “zero waste.” We are led to consider consumption patterns, use, re-use and recovery of waste products.  Even if we don’t get to zero waste, perhaps we may re-consider the growing hills of garbage and come to regard them as resources for new industries. Recycled plastic is already being used to make shoes and bags; fabric and furniture, or construction and road building material. A few countries have turned to renewable sources of energy; and support industries that produce zero waste. Other communities are repairing and repurposing used items.

Perhaps, this is an exercise that may be developed as a study for a class of primary or secondary students for any school term in 2018.

Step 1:
In a day, or a week, consider all the waste that is generated in your home. It would be useful to sort the waste materials into bins or boxes. Even if you don’t do this, create a chart on the fridge. Keep a Waste Diary in an old notebook.  List categories such as:
Glass (bottles);
Plastic (include shampoo bottles, beverage containers, styrofoam packaging);
Organic (vegetable and fruit peels, egg shells, fish and chicken bones);
Oils (cooking oil or grease; engine oils and lubricants);
Paper (newspapers, cardboard boxes, waste paper);
Other (appliances, used clothing, books, toys, pots, furniture).
Whether you are actually sorting and storing, or putting everything into the household garbage, record the items that you discard each day, in a week, a month, a year.

Step 2:
Consider how you might re-use each item that you are discarding.
Glass beverage bottles are re-usable or returnable. Carib Glass recovers their beer bottles; others are collected by Carib Glass to be ground up and remade into new bottles.
Plastics are the most insidious of the waste; they get into every waterway. You may want to consider how you can reduce your plastic waste by refusing to use plastic straws and single use containers and cutlery, for instance.  Carry your personal reusable water bottle. Some people are even carrying cutlery and standard jars for drinking. Before you select soft dinks in plastic bottles, think of how you will dispose of the bottle – as well as the nutritional value of a sugary soda beverage.
For Organics, you may consider feeding your chickens, or building a compost bin. If you decide to compost – or to simply put vegetable and fruit peels in a secluded spot in the yard – you will be able to add cuttings from the yard, shredded newspaper and some smelly waste (bones for instance) to the compost. It’s better not to add bones or waste food, since these may encourage rats and stray animals.
Cardboard and paper waste may be used in composting; and around plants to keep weeds down.

You may want to encourage your community to place collection bins for the different recyclables. Seek information and participate in the THA recycling and waste disposal plan.


Step 3:
Think about how much of your waste comes to your home as part of what you purchase in the grocery, or market or store.
If you carry your own reusable bag when you go shopping (to the grocery, the market or the mall) you can refuse the plastic bag that seems to be part of every purchase.
Fill and carry your reusable water bottle.
Refuse plastic straws.
When the grass or bush at the roadside or in gardens are cut, why are they put into plastic garbage bags. Where do these bags go? Better use of cuttings might be around growing trees or in compost.
Wherever possible, try to minimize the plastic bags or wrappings that accompany every purchase.

Step 4:
Become more aware of where waste goes in Tobago. Are there waste dumps in your village? Is there regular collection by the contractors who collect your garbage? Where does your garbage go? Are there dumps that are open to scavenging dogs, or on a drain that goes to the sea? Most of the garbage collected in Tobago is supposed to go to the landfill at Studley Park? Do you know where this is? Could you visit? Form a community or school group and make your project  "what happens to waste" that is collected in your area.

Rosanna Farmer, Plastikeep founder and operator, believes that individuals working in communities are the key to reducing, re-using and recycling waste streams. Over the long-term, it is possible for community-based organisations to create and support business based on the recapture of materials from waste streams.

In Trinidad and Tobago, the framework for waste management and recycling is supported by legislation and policy already articulated. The Beverage Container Bill of 1999 allows for recovery of plastic and glass bottles, cans, tetrapaks and cardboard containers through a deposit and refund system. At this time, the refund is only applied on glass bottles from Carib Glass, the company which also accepts all other glass bottles for recycling.

The Integrated Solid Waste/ Resource Management Policy of 2012 ambitiously articulated a strategy for waste management that would be led by Local Government with participation from private and public sector organisations, communities and NGOs. It envisages a holistic approach where citizens take responsibility, understand the processes by which waste is generated, and take part in finding solutions to reduce waste and to recycle, recover and re-use materials and products. Behavioural change takes place at personal and household and community levels; new information, technology and opportunities should create continuous learning cycles.

The National Environmental Policy was adopted in Parliament in 2006. Although the policy proposes that the power to protect the environment should rest in the hands of citizens’ groups and communities, the policy recognizes the government’s role in managing and penalizing polluters especially in the industrial and mining sectors.

The challenge now is to get citizens on board, through public information and sustained activities especially in schools and community groups.

We need to be like Barbados! A site adjacent to the landfill in Barbados has been turned into an industrial facility where garbage is sorted: plastic, glass, metal and electronic, cardboard and organics. Sustainable Barbados is a private-public sector partnership intended to reduce waste to the landfill while recovering and re-using materials. It is already creating employment, and a viable business from composting. The Sustainable Barbados Recycling Centre is located at Vaucluse in the Parish of St. Thomas, Barbados, on a 35-acre site.