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Scientists revamp open ocean observatory

The National Oceanography Centre (NOC) and the UK Met Office have joined forces to revamp the Porcupine Abyssal Plain Sustained Observatory (PAP-SO) in the northeast Atlantic.

13 July 2010, by Tom Marshall

The National Oceanography Centre (NOC) and the UK Met Office have joined forces to revamp the Porcupine Abyssal Plain Sustained Observatory (PAP-SO) in the northeast Atlantic.

The site now monitors atmospheric variables like wind speed and air pressure, as well as the data on the physical, biological and chemical properties of the ocean that it already produced.

This data will help scientists understand the impact of environmental change on the ocean and improve our ability to predict the future climate.

'The latest enhancement of the PAP-SO infrastructure with a Met Office surface buoy and atmospheric sensors is a huge achievement, marking the first collaboration between the UK Met Office and NOC since the move of the Met Office marine engineering team to the NOC in Southampton in 2008,' says Professor Richard Lampitt of NOC, who led the team onboard RRS James Clark Ross.

The Met Office ODS buoy.

With more than 25 years of history, the PAP-SO was first developed in the 1980s as an environmental sampling site designed to measure open ocean processes from the surface to the seafloor. The site's remote location, some 300 nautical miles from the nearest coastline, meant scientists could originally visit it just once a year on a research vessel, whereas now data is transmitted back to shore by satellite link.

Over the years the range and sophistication of instruments at the site has grown enormously. Early autonomous samplers including moorings with sediment traps for particle flux and seafloor time-lapse photography continue to this day. Since 2002, a mooring line equipped with sensors has monitored the upper ocean – from the surface to a kilometre deep – transmitting data back from the surface buoy via satellite almost as quickly as it is collected.

The latest additions to the upper ocean sensors include devices to measure conditions such as oxygen and light penetration, to complement ongoing readings of how much chlorophyll is present – and therefore how much photosynthesis is being done by plankton – nitrate and CO2. The combined datasets will allow inter-disciplinary research, improving understanding of ocean circulation, production of biomass by phytoplankton and carbon cycling in the North Atlantic.

'The PAP-SO produces a diverse, high quality dataset of climate and ocean variables. These are vital for scientific research but also provide much-needed in-situ data for assessing the environmental status of our European seas. Data are also used to validate climate and ocean models, reducing uncertainty and informing policy about natural variability and longer-term trends in our ocean,' says Dr Kate Larkin, a biogeochemist at NOC.

Holothurian (sea cucumber) Amperima rosea on the abyssal seafloor at PAP.

Since 1989, the seafloor monitoring capability has featured a time-lapse camera on the seafloor, called the Bathysnap system, which automatically takes a picture of the seabed every eight hours. This has shed light on life on the abyssal seafloor and the reliance of seafloor ecosystems on the quality and quantity organic particles raining down from the surface waters. On the most recent cruise the team replaced the camera with a new digital model. Before long, images will be transmitted in real time from the site, enabling instantaneous viewing of the abyssal depths of the North Atlantic.

As well as deploying the new observatory, scientists aboard conducted additional research, including experiments on plankton and how it will respond to ocean acidification. A team led by Dr Debora Iglesias-Rodriguez of NOC used deep Atlantic water rich in CO2 in culture experiments with the species of marine algae Emiliania Huxleyi to understand how increasing levels of atmospheric carbon dioxide will affect these plankton, whose chalky shells may be at risk of dissolving in more acidic conditions.

The PAP-SO is funded under the Oceans2025, the Natural Environment Research Council's integrated marine research programme. It is also part of the EuroSITES European network of ocean observatory sites.