UNDERSTANDING AND PREDICTING DEAD ZONES IN THE SOUTH CHINA SEA

Hi, I’m Bastien Queste from the University of East Anglia in England, and I’m here to tell you what you can do to help science happen!

The South China Sea is one of the most interesting and diverse seas on the planet, and the islands around it depend on it enormously. In this part of the world, for example, aquaculture and fishing make up a vital part of local people’s livelihood.

In the South China Sea, however, a number of natural events occur seasonally, which cause very serious problems for the whole region. These natural events are called algal blooms, and they’re composed of microscopic plants which normally feed and sustain fish and a whole range of other animals. But when these algae ‘bloom’ beyond what the ecosystem can cope with, it can lead to a huge amount of organic matter decaying and sucking up the oxygen in the water. This causes what we call dead zones.

These dead zones occur all around the world, and we’re gaining a better understanding of how they work every day. But some regions struggle to monitor these problems because of harsh conditions at sea and the lack of necessary instruments.

This competition could change all of that! Wavegliders are amazing instruments – they’re powered by waves, they go where you want them to and they can measure everything from the temperature of the water to the health of the algae and even record whale song. At the same time, they can measure what goes on above the sea to evaluate how winds and rain influence the ocean.

What we want to do is launch of waveglider in the South China Sea, right between Sumatra and Indonesia. Not only is this one of the big hotspots for harmful algal blooms and dead zones, it’s also the site where another project by the University of Washington, the University of Warsaw and the University of East Anglia will be running.

This other project is interested in atmospheric waves that change wind patterns and rainfall over all of South East Asia. Now, they already have underwater gliders to the west of Sumatra and to the east of Indonesia. But nothing in between! By putting a Waveglider between the two islands, not only can we monitor the ecosystem in the South China Sea, we can also fill a substantial gap and provide another platform for their measurements.

In exchange, the underwater data they gather can be used to understand the in- and outflows into the South China Sea and look at the properties to gain a better understanding of what drives these phytoplankton blooms – hopefully even helping us predict where and when they’ll occur!

We get to kill two birds with one stone. One instrument, two projects !

We hope you will chose to vote for this video as this is the only way we can move forward. Local ships can’t withstand the harsh conditions offshore during the monsoons – a critical period which determines the strength of blooms – and other underwater glider platforms are simply not able to cope with the shallow depths and strong currents of this region. A Waveglider is not only the ideal tool, but the only tool we can use for this project.

We hope you’ve enjoyed the video, and if you are interested, please contact us, we’re always happy to share what we know!

The eastern equatorial Indian Ocean and seas of the maritime continent are at the heart of the tropical warm pool. They are a region of high sea surface temperatures (SSTs) that support deep atmospheric convection in the region. Hence, ocean-atmosphere interactions will likely be important for the generation and development of the atmospheric convectively coupled equatorial Kelvin waves (CCKWs) that are the main focus of this project. These atmospheric processes play a critical role in determining the magnitude and variability of harmful algal blooms and deoxygenation

The surface conditions and mixed layer structure of the ocean will have a strong control over these ocean-atmosphere interactions. We propose detailed (high vertical resolution and high temporal resolution) measurements of the ocean surface and mixed layer before, during and after the passage of CCKWs, on an equatorial transect of the CCKW propagation path along 1N. The diurnal cycle, particularly the development of the surface diurnal warm layer, has recently been identified as an important component driving productivity in shelf seas and linked to the intensity of harmful algal blooms.

The sea between Sumatra and Borneo is very shallow (order 100 m) and is unsuitable for ocean gliders, due to the strong currents and lack of vertical distance to manoeuvre. However, a waveglider is an ideal platform to deploy in these conditions. A waveglider is an autonomous surface vehicle driven using solar and wave power. It is equipped with instruments to measure surface meteorological conditions (automatic weather station: air temperature, humidity, wind speed and direction, precipitation, radiation fluxes) and near surface oceanographic conditions (profile of temperature and salinity over top few metres). Hence, it is an excellent platform to measure ocean-atmosphere interaction and biological productivity in shallow seas. We will deploy a waveglider at approximately 108E, 1N, to measure the oceanic and atmospheric conditions related to the passage of CCKWs between Sumatra and Borneo.

The waveglider would be deployed alongside deploy two ocean gliders in the equatorial eastern Indian Ocean to the west of Sumatra, one at 94E, 1N, and one on the continental shelf at 96.5E, 1N. These two ocean gliders will measure ocean-atmosphere in the Indian Ocean, particularly that related to the eastward propagation of CCKWs that have developed over the Indian Ocean and are approaching Sumatra. Finally, an ocean glider will be deployed in the Celebes Sea at approximately 122E. Due to the island of Sulawesi along 1N, this deployment will be further north, at approximately 2N. The Celebes Sea is over 1000 m deep, highly suitable for ocean glider deployment.

The ocean gliders and wave gliders have long durability and battery life, and can be deployed for up to 4 months, enabling long, continuous time series to be measured, and many CCKW events to be sampled.

All biogeochemical measurements, including dissolved oxygen and chlorophyll fluorescence, will be made available for the dead zone project and will be valuable measurements for the wider IIOE2 and YMC campaigns, in a data-sparse region.

The two ocean gliders in the Indian Ocean west of Sumatra would be deployed from the island of Pulau Nias (97.5E, 1N). The gliders would be freighted to Gunungsitoli (the main town on Pulau Nias) on the eastern side of the island. Road transport would then be needed to reach the western side of the island, then a small boat to take gliders a few miles offshore into deeper water, where they can be launched. Similar logistics would be needed from a base to deploy the wave glider, and the third ocean glider in the Celebes Sea. Power and internet would be needed on land. Similar logistics would be needed for retrieval. Funding would be needed to prepare the gliders (battery replacement, ballasting etc.) and to cover Iridium satellite communications costs during deployment, and for travel and subsistence for personnel to deploy and retrieve the gliders. UEA (Matthews, Queste, and the UEA ocean glider team) have considerable practical and science experience in operating ocean gliders and scientific analysis of glider measurements.

This project would have interactions with other related projected in the region, including BoBBLE during 2016 in the Bay of Bengal, and the wider YMC programme.

Personnel

Dr Bastien Queste, University of East Anglia, UK. Physical oceanography and ocean biogeochemistry; ocean glider operations.

Prof. Adrian Matthews, University of East Anglia, UK. Ocean-atmosphere interactions; tropical dynamics; intraseasonal variability; observations; modelling; ocean gliders.

UEA Ocean Glider Team (led by Prof. Karen Heywood). Ocean glider operations.

Dr Dariusz Baranowski. Convectively coupled Kelvin waves; ocean-atmosphere interactions; glider operations.

Dr Kyla Drushka, Applied Physics Laboratory, University of Washington, US. Physical oceanography