World Oceans Day - 8th June

With healthy oceans comes a healthy planet, so today is a day to take action and learn how to conserve, preserve and protect our oceans.

Oceans account for about 71% of the Earth’s surface, and approximately 97% of Earth’s surface water. Aside from simply taking up the majority of the Earth’s surface, the oceans (Pacific, Atlantic, Antarctic, Arctic, and Indian) have massive impacts on everything that occurs on the planet, from influencing climate, holding a large share of the planets biodiversity – with over 230,000 known species residing in it -- and providing humans with an abundance of resources necessary for life, from energy, to food, to transportation.

Here in Vava'u, one of the most important ecosystems we are striving to protect is the coral reefs. Coral reefs are masses of calcium carbonate (CaCO3) composed of skeletons of tiny, colonial marine organisms. They form in tropical and subtropical areas of the world and act as a means of helping to stop shoreline erosion through absorbing wave energy. Their rigid, complex framework, on which a variety of creatures and structures thrive (such as anemones, sponges, hydroids, and other sessile invertebrates) are regions of high primary productivity, making them excellent hosts of biodiversity, habitat availability, and food sources.

Mangrove forests are another ecosystem that are abundant in Vava'u. They are series of trees along muddy shorelines with root systems that curve upwards to obtain oxygen and nutrients that are lacking in the mud of which they grow. Their root systems and foliage provide habitats for a variety of coastal creatures; as well, their strong root system stabilizes shorelines against storm surges and oceanic changes, filters pollutants, and slows surface runoff.

Biodiversity loss is a major issue that our coastal and marine ecosystems are facing today. This loss is attributed to climate change and sea temperature rise, rubbish impacting species food systems, as well as things such as overfishing and over harvesting. With this loss of biodiversity, ecosystems are less able to produce and maintain primary and secondary production, which effects all levels of the food chain. Additionally, ecosystems are less able to adequately withstand natural occurring disturbances, since they are left smaller and more vulnerable. Decreasing biodiversity affects all stages of an organism’s lifecycle, as it reduces habitats used for nurseries and limits potential habitats for species when they become fully grown. Biodiversity helps to filter and detoxify marine and coastal ecosystems, without which can lead to algae blooms and dead zones, making life for other organisms almost impossible. In Vava'u biodiversity is essential for both fishing and tourism, as local people rely on oceans and its products to stimulate the communities and the local economy. You can help to maintain the biodiversity of our oceans by making sure rubbish ends up in bins, using cloth bags instead of plastic bags, keeping fishing and gleaning practices within sustainable levels (not overfishing), removing old fishing lines or aquaculture structures, and walking or biking instead of driving to reduce emissions which contribute to sea temperature increase.

One of Vava'u's treasures is its humpback whale migration season from mid-July to October. Because of this, it is vital that we work to keep our oceans clean and healthy, so that these creatures have a home to give birth and feed before heading back to the Antarctic for the summer. Whales exist as a keystone species in marine ecosystems, therefore threats to their populations effect other populations, as everything in an ecosystem is connected via the food web and carbon cycle. Whales enhance ecosystems through a top-down trophic cascade. The iron and other nutrients they defecate stimulates primary productivity, thereby enhancing krill and other fish productivity. Whales keep our fish populations thriving, so we need to help them by providing a healthy home for them and their young. 

One of the easiest ways to help the oceans is to challenge yourself to go plastic free! It is estimated that 90% of the rubbish in the ocean (specifically in the infamous "garbage patches" floating in the Atlantic, Pacific, and Indian oceans) is plastic that cannot degrade, and therefore either accumulates or is ingested by marine organisms. Going plastic free as often as possible can help to reduce the impact that it has on ecosystems and their inhabitants!

HUMPBACK HIGHLIGHTS (Protect our Pacific Whales)

• Megaptera novaeangliae
• The South Pacific (Oceania) population remains on the IUCN Red List for endangered species
• Humpback whales live an average of 50 years
• They can grow up to 18 m long, with females being typically larger than males 
• Newborns are on average 4.5 m long
• Species of baleen whale 
• Distinct attributes of these whales are their breaching and slapping of the water

Join in on programs in your area to support the health and biodiversity of your ocean! Our activities take place this upcoming Saturday 11th June, when we will engage youth members in their coral reefs. Our event is sponsored by the Waitt Foundation with the use of the vessel WhaleSong from Jones Business Services

Feeling hot hot hot

and yes not just us humans, but again our corals are under thermal stress  with hot ocean water temperatures over a prolonged period of time. Other environmental issues that can cause coral bleaching is run off and pollution, extreme low tides which can cause an excessive amount of sunlight on the corals.

Just last week on a survey we noticed corals paling and bleaching in shallow waters on the reef flats and following on from the bleaching event recorded in February through April 2014, we are again watching closely.

Firstly lets just talk about the basics of coral reef formations and corals themselves:

Corals are made up from rock (limestone) which forms the skeleton and attachment for the coral, plant (zooxanthellae) that gives corals there colour as well as photosynthesizing and producing oxygen. The zooxanthellae and the polyp have a mutualistic relationship each providing benefits to the other.

The  animal is a polyp that has tiny tentacles that extend out and catch passing particles which feed the coral. There can be thousands of small polyps on a single coral head and millions spread over a coral reef area.

Anatomy of a coral polyp © Encyclopaedia Britannica.

Coral reefs provide many functions or services to people including food, enjoyment and recreation and protection from climatic events such as storms, tsunamis and waves. If a coral reef is not healthy and in balance these services can be affected. Keeping coral reefs healthy through managing fishing, reducing anchoring and pollution are some of the ways to keep our ecosystems in balance.



So what is bleaching?

This coral bleaching infographic by NOAA provides great simple information on the causes and impacts of bleaching.

When oceans temperatures exceed the normal threshold for corals (between 23C and 29C) and maintain that heat for a period of time, corals will start to drop the zooxanthellae, the corals begin to look very bright in colour, this is known as paling. If the temperatures remain high, the coral then may further bleach turning itself bright white. At this stage corals still may recover if water temperatures reduce quickly and the algae returns.

If the corals remain bleached and the water temperatures remain high, coral mortality may become an issue. Once a coral has completely bleached it is at risk of no longer providing food or habitat for marine animals as well as protection for shorelines from storms and large waves.

Those bright hot red spots are all around the waters of Tonga at the moment.

Chart showing possible bleaching stress between February and May 2015.

How can you help?

VEPA is a supporter of the CoralWatch program which can be used by divers and snorkelers to easily monitor changes in reef colour. Its free to do and we will input the data, so please if you would like to join in pop by the VEPA office located at the bottom of the Guttenbeil Plaza.