GeoLog

Ocean Sciences

Underwater robot shares ocean secrets

Underwater robot shares ocean secrets

Buoyancy-driven drones are helping scientists paint a picture of the ocean with sound.

Around the world, silent marine robots are eavesdropping on the ocean and its inhabitants. The robots can travel 1000 metres beneath the surface and cover thousands of kilometres in a single trip, listening in on the ocean as they go.

These bright yellow bots, known as Seagliders, are about the size of a diver, but can explore the ocean for months on end, periodically relaying results to satellites.

Researchers have been utilising gliders for about 20 years, first using them to measure temperature and salinity. But over time, scientists have expanded their capabilities and now they can record ocean sounds.

You can learn a lot from the recordings if you know how to read them. The background noise is produced by high winds, the low frequency rumble comes from moving ships, and the punctuating whistles and clicks are produced by different marine species.

Sperm whale and dolphin echolocation clicks. Every two seconds you hear a loud click, the sound of a sperm whale. The more rapid clicks correspond to dolphins. Credit: University of East Anglia

Pierre Cauchy, a PhD researcher from the University of East Anglia, UK, has been using seagliders to create an underwater soundscape across the Mediterranean, Atlantic and Southern Oceans. He presented his latest findings at the EGU General Assembly in Vienna last week.

Here in the ocean, the nights can be noisier than the days. When the sun goes down, fish sing out in chorus, a sound that rings out at 700 Hz. “I wasn’t expecting that, it was serendipitous,” says Cauchy. It’s not only fish that can be picked up by the gliders; dolphins and whales make characteristic whistles and clicks, meaning species can be identified from their vocal patterns alone.

The next step is to cross check the recordings with others made in the area, and confirm which species he’s been listening to. In the future, Cauchy hopes the technology will be used to monitor changes in ecosystem health over time.

While it’s hard to know what a healthy ecosystem sounds like, you can monitor the same spot from year to year and work out whether it is healthier, or less healthy than it was previously. A more healthy ecosystem may be filled with the sounds of different fish, and other species, representing a diverse, species-rich habitat.. A less healthy one would be quiet, or more monotonous.

Pod of long-finned pilot whales in the North Atlantic. Credit: University of East Anglia

The sound of a pod of pilot whales – bright areas indicate bursts of sound at a particular frequency. The patterns and frequencies differ for each species. Credit: Cauchy et al. (2008).

Scientists could also use gliders to fill gaps in our understanding of extreme weather around the world, especially in places where collecting data is a challenge, like the high seas. “That’s the good thing with gliders, you can send them where data is needed,” emphasises Cauchy.

Researchers have been using satellite data to validate wind speed models and map weather events like hurricanes, but even satellites need to be calibrated against measurements made on the Earth’s surface. The seagliders can do just that; hydrophones pick up wind at two to 10 kilohertz and the faster the wind, the louder the sound. “The more in-situ data you have, the better your satellite data is, and that’s better for the models,” Cauchy explains.

Future work could see scientists sending gliders into hurricanes to measure wind speeds reached during extreme weather events.

By Sara Mynott

References

Cauchy, P. Passive Acoustic Monitoring from ocean gliders. EGU General Assembly. 2018. 

EGU General Assembly press conference recording available here.

Imaggeo on Mondays: Iceberg viewing in Cape Spear, Newfoundland, Canada

Imaggeo on Mondays: Iceberg viewing in Cape Spear, Newfoundland, Canada

Cape Spear in Newfoundland, Canada is the easternmost location in North America and one of the few places in the world where you can contemplate icebergs from the shore. Every year, about 400 to 800 bergs journey down to this particular point. These 10,000-year-old ice giants drift along the northern shore of Newfoundland with the Labrador Current.

About 90 percent of these icebergs come from western Greenland glaciers, where they break off directly into Baffin Bay. Often these bergs remain in the bay for several years, preserved by the cold arctic waters and circulating along with local currents. Eventually, many icebergs escape through the Davis Strait, drifting down the Labrador Current and passing through Iceberg Alley to reach the Grand Banks of Newfoundland, the region of the North American continental shelf where Cape Spear is situated. This journey from Greenland to the Grand Banks usually takes between two and three years.

Cape Spear is just a few kilometres from Newfoundland’s largest city, St. John’s, and attracts many tourists during spring and early summer months to enjoy the immense icebergs. The chances of seeing them depend greatly on the temperature, wind direction, ocean currents and amount of sea ice during the winter, which protects icebergs from erosion. The icebergs have a great impact on Newfoundland’s identity and economy, bringing tourists and even giving breweries unique ice for beer and liquor production.

On the other hand, the floating ice can be a hazard to oil platforms and cargo boats. Smaller bergs can be especially hazardous since they are harder to detect with marine radar. If deep enough, the icebergs can also damage seabed structures like pipelines and cables. Thus, it is important to keep monitoring the dynamics of icebergs, especially since there will likely be a greater volume of ice breaking from the Greenland glaciers and drifting in the North Atlantic due to climate change.

By Simon Massé, PhD student, Université du Québec à Rimouski, Canada

References

Barber, D.G., Babb, D.G., Ehn, J.K., Chan,W., Matthes, L., Dalman, L. A., et al.: Increasing mobility of high Arctic Sea ice increases marine hazards off the east coast of Newfoundland, Geophysical Research Letters, 45,2370–2379, https://doi.org/10.1002/2017GL076587, 2018.

Diemand, D., Icebergs, Encyclopedia of Ocean Sciences, 3: 1255-1264,  2001.

Iceberg Finder, Icebergs Facts. Newfoundland & Labrador Tourism, 2012.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

 

Geopolicy: Combating plastic pollution – research, engagement and the EU Plastic Strategy

Geopolicy: Combating plastic pollution – research, engagement and the EU Plastic Strategy

Awareness around the prevalence of plastic pollution, particularly in our oceans, has been growing over the last few years. This is not surprising considering that plastic production has surged from 15 million tonnes in 1964 to 311 million tonnes in 2014 and models have shown that this number will double again within the next 20 years in a business as usual scenario. Furthermore, research conducted by the European Commission estimated that Europeans generate a combined 25 million tonnes of plastic waste annually with less than 30% being collected for recycling.

All this sounds quite overwhelming but the real problem is, while we can estimate the production of plastic with some certainty, it is extremely difficult to know exactly how pervasive plastic pollution is on a global scale and how it is impacting human health and our environment. There are a huge number of researchers from a variety of scientific disciplines currently working on these issues. Some prominent research areas related to plastic pollution include:

  • Microplastics – a plastic pollutant that we still understand relatively little about. Microplastics are small plastic particles (<1 mm) that originate from larger plastic waste erosion and through the abrasion of synthetic fibres commonly used in clothing. A 2017 study on microplastics found that 80% of the drinking water samples collected on five different continents tested positive for the presence of plastic fibre. The exact environmental and health implications of microfibres still isn’t clear.
  • Location and movement – Understanding the location and transport pathways of plastic pollution can help us estimate how much there is, where it is and how it might be impacting the ecosystem. Unfortunately, the location of most plastic pollution is still unknown. Recent research suggests that there are roughly 300 billion pieces of floating plastic in the polar ocean while other research shows a significant amount of plastic is entering the food web.

A bottle dropped in the water off the coast of China is likely to be carried eastward by the north Pacific gyre and end up a few hundred miles off the coast of the US. Photograph: Graphic. Credit: If you drop plastic in the ocean, where does it end up? The Guardian. Original Source: Plastic Adrift by oceanographer Erik van Sebille. Click to run.

  • Lithosphere – Although the location of some plastics is unknown, others are now being found where we would least expect them… as part of the lithosphere! A new type of stone (plastiglomerate) has recently been discovered in Hawaii. This stone, which the research team believes is a result of burning plastic debris in an open environment, was found to be primarily composed of melted plastic, beach sediment, basaltic lava fragments and organic debris.

The methods used to communicate plastic pollution research, and its potential impact on the environment and human health, have been extremely effective in both mobilising citizens to reduce their own plastic use and is showing policymakers that the public wants a large-scale transformation.

As a result, plastic pollution is now being tackled by the EU Plastics Strategy, a political action that was largely driven by research and the subsequent public advocacy.

What is the EU Plastics Strategy?

The EU Plastics Strategy was adopted on 16 January 2018 after research into the extent and impacts of plastic pollution was conducted by a research team commissioned by the European Commission. The strategy aims to change the way plastic products are designed, used and produced within the EU. The strategy also outlines the European Commission’s primary goal of a 55% plastic recycling rate, with all plastic packaging in Europe recyclable or reusable, by 2030.

To achieve this, a €350m budget for research into innovative plastic design, production and collection has been reserved with the additional possibility of a tax on unsustainable plastic production.

Furthermore, the strategy is proposing better recycling programmes across all EU countries, clearer labelling on packaging so consumers fully understand its recyclability, easier access to tap water in public areas to reduce the demand for bottled water, and a ban on microplastics in cosmetics and personal care products.

With these aims, the European Commission hopes that the EU Plastic Strategy will reduce plastic pollution while also help the EU transition into a circular economy and reach their goals on sustainable development, global climate and industrial policy.

There’s still a long way to go

The release of the Plastics Strategy is just the beginning of the EU’s fight against plastic pollution – it’s the blueprint for legislation that will be implemented over the next couple of years. You can view the European Commission’s timeline of actions, directives and policies related to the strategy here.

Although the Plastics Strategy is only the first step towards implementing legislation, it is a strong signal to investors and the private sector that there is a lucrative market in plastic alternatives and recycling technology. This means that there is likely to be more money pumped into finding solutions on top of the €350m reserved for plastic research and innovation by the EU.

What’s the positive take home message?

Despite plastic pollution being a challenging and frightening problem, it is also a fantastic example of how researchers, civil society, policymakers and the private sector play different but complimentary roles in creating large-scale change. With the initial crisis highlighted by researchers, mobilised by civil society, acted upon by policymakers and invested in by the private sector, the threat of plastic pollution can also be seen as the beginning of a success story – we just have to follow it through!

Further information

Imaggeo on Mondays: Robberg Peninsula – a home of seals

Imaggeo on Mondays: Robberg Peninsula – a home of seals

This picture is taken from the Robberg Peninsula, one of the most beautiful places, and definitely one of my favorite places in South Africa. The Peninsula forms the Robberg Nature Reserve and is situated close to the Plettenberg Bay on the picturesque Garden Route. “Rob” in Dutch means “seal”, so the name of the Peninsula is translated as “the seal mountain”. This name was given to the landmark by the early Dutch mariners, who observed large colonies of these noisy and restless animals on the rocky cliffs of the Peninsula. Seals still inhabit this area today.

The Peninsula is constituted of two rocky parts, rising above the sea level at about 150 m, and which are separated from each other by the “Gap” – a low and narrow sandy neck. The length of the Peninsula is about 4 km and the width is up to 750 m, which narrows down to 200 m at the “Gap”. The eastern rocky part forms an extension to the south – another tiny peninsula, “the Island” (on the picture). “The Island” is a small rocky area connected with the main Peninsula by a narrow strip of sand. This sand bar is essentially a beach washed by water at its both long sides. With “the Island” the entire Peninsula has a shape of a mitten, which thumb is looking down.

Robberg Island is entirely built up by the sedimentary rocks: quartzites of the Table Mountain Group (part of the Cape Supergroup), and Robberg’s Formation sandstones, conglomerates and breccias. Table Mountain Group is formed some 500-330 million years ago; and the Robberg’s formation, which is the part of the Uitenhage Group, is around 120 million years old and related to Gondwana break-down. Upper parts of the Peninsula are covered by the Quaternary dune deposits. At the moment the rocks of Robberg Peninsula are actively eroded by the Indian Ocean waters.

Robberg Peninsula is a beautiful home of many marine bird species, small reptiles, seals and indigenous plants. The Nelson Bay Cave, situated on the Robberg Peninsula, is one of the oldest caves, inhabited by human. It was occupied from 120 000 years ago, by various tribes, including San and Khoikhoi people. Nelson Bay Cave was formed due to the erosion caused by the ocean waves.

Description by Elizaveta Kovaleva, post-doctoral researcher at University of the Free State, in South Africa

If you pre-register for the 2018 General Assembly (Vienna, 08–13 April), you can take part in our annual photo competition! From 15 January until 15 February, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.