Science

Ocean ‘tea’

Dr Richard Zimmerman and Dr Victoria Hill are investigating coloured dissolved organic material. This ocean ‘tea’ is derived from disintegrating marine and plant matter steeped in cold seawater.

Marine communities

The oceans are swarming with tiny organisms that, whilst invisible to the naked eye, play a vital role in the delicate balance of whole marine ecosystems. Dr Helen Findlay and Dr Ceri Lewis build on research first began in 2010 into these minute creatures.

Following Arctic fingerprints

From ice to ocean; Kristina Brown is tracing CO₂ and other chemical ‘fingerprints’ from the sea ice into the surface waters of the Arctic Ocean.

Marine snow

In the world’s oceans, from the Arctic to Antarctica, there is a natural phenomenon known as marine snow. Dr Oliver Wurl is following the fate of these tiny bits of matter as they sink down into the oceans depths.

Marine Snow

In the world’s oceans, from the Arctic to Antarctica, there is a natural phenomenon known as marine snow. Tiny bits of matter bind together and sink down into the oceans depths, transporting carbon dioxide from the air to the bottom of the sea.

Transparent exopolymer particles (TEP) are the glue that binds marine snow together. These spontaneously assembling particles are formed from materials excreted by phytoplankton. There is concern that as the ocean acidifies, from increasing levels of CO₂ dissolving in seawater, the amount of material excreted by phytoplankton may also increase. This, in turn, could cause more TEPs to assemble. Both of these effects have the capacity to dramatically alter the natural cycle of the oceans and the environment for marine life.

However, it is also possible increasing amounts of marine snow falling to the ocean floor will draw down the increasing levels of atmospheric CO_2. This could change the rate, or even prevent, ocean acidification.  Scientists need to know more about both the potential problems and benefits of increased amounts of TEPs to assess the overall risk of acidification.

Experiments

Building on data Dr Oliver Wurl captured in Catlin Arctic Survey 2010, his objective is to better understand biogeochemical fate of TEPs in the Arctic Ocean, and in a more acidic ocean. He will investigate:

• the rate of TEP assembly in seawater samples with varied nutrient and CO₂ levels
• the development and decline of a phytoplankton bloom in samples
• the amount of bacterial activity (disintegrating and assembling TEPs)
• the levels of primary production (a source of TEP material)

Outcomes

Many studies have investigated the potential impacts of ocean acidification on marine life, but less on possible changes in biogeochemical cycles. Dr Oliver Wurl’s research at the Ice Base will generate data on an under-researched field, and inform climate modelers on a potentially unaccounted for carbon sink. This is important not only for future climate models but to help policymakers and business to more comprehensively assess risk and set policy.

Researcher & university:

• Dr Oliver Wurl, Department of Ocean, Earth and Atmospheric Sciences, Virginia, USA

Collaborating researchers & universities:

• Associate Professor Svein Vagle, Institute of Ocean Sciences, British Colombia, Canada
• Professor Gregory Cutter, Department of Ocean, Earth and Atmospheric Sciences, Old Dominion University, Virginia, USA

Ocean ‘tea’

The Bio-Optics Research Group (BORG), led by Dr Richard Zimmerman and Dr Victoria Hill, will spend 42 days at the Ice Base investigating coloured dissolved organic material, also known as chromophoric dissolved organic material (CDOM). This ocean ‘tea’ is derived from disintegrating marine and plant matter steeped in cold seawater.

Photosynthetic pigments in plants support the food web by using energy from sunlight to synthesise sugars from CO_2. Like plants, CDOM also absorb light energy but this energy is released as heat. High concentrations of CDOM in the surface layer of the Arctic Ocean trap heat energy at the surface that would otherwise penetrate into the deeper ocean below.

Researchers Dr Victoria Hill and David Ruble will determine the sources of CDOM entering the Arctic Ocean (from land, sea or ice) and how CDOM mixes with the water immediately below the sea ice.

They will also analyse the impact of CDOM on water temperature at different depths and how quickly this ocean tea is damaged and broken down by light, as this will dictate the time scales of heating (days, weeks or months).

Warming of the surface waters affects the rate of sea ice melt and the layering of the Arctic Ocean, which in turn impacts ocean circulation. This research will help scientists determine if the loss of sea ice from the Arctic Ocean and increased freshwater runoff from nearby land, could affect sources of CDOM, and in turn surface water heating.

Experiments

Researchers will conduct extensive on-the-ice (in situ) observations of CDOM dynamics. They will measure:

• light absorption by CDOM within the sea ice
• light absorption by CDOM at different water depths
• CDOM production by ice algae and phytoplankton

Sensitivity of CDOM to decay from light and environmental changes

Outcomes

Knowledge derived from the experiments will be used to inform the ice-ocean model PIOMAS how CDOM affects the absorption of solar radiation by the surface layer of the ocean. This will allow scientists to further explore the changing environment under the ice and its possible impact on thermohaline circulation and sea ice dynamics.

Researchers:

Principal investigator: Dr Richard Zimmerman, Head of the Department of Ocean, Earth and Atmospheric Sciences, Old Dominion University, Virginia, USA

Ice Base researchers: Dr Victoria Hill & Mr David Ruble, Department of Ocean, Earth and Atmospheric Sciences, Old Dominion University, Virginia, USA

Collaborating universities & institutes:

• Jinlun Zhang, University of Washington, Seattle, USA

For further information visit the BORG webpages: http://sci.odu.edu/oceanography/directory/faculty/zimmerman/researchpage/index.shtml

Following Arctic fingerprints

Dr Lisa Miller’s research team is investigating the transport of CO₂ and other chemical ‘fingerprints’ from the sea ice into the surface waters of the Arctic Ocean.  They want to observe potential changes in the thermohaline layering of the Arctic Ocean, and the removal of CO₂ from the atmosphere.

The group is aiming to help answer a 30-year old hypothesis; does sea ice formation transport CO₂ into the deepest depths of the ocean?   Researcher Kristina Brown will trace the fate of these chemicals to investigate their impact on ice-facilitated ocean circulation systems, such as North Atlantic deep water formation, and consequently thermohaline circulation.

Scientists know that brine (extremely salty water) sinks from the Arctic into the deep currents that circle the world. However, it is less clear whether that process also transports CO_2. Although sea ice is enriched in carbon, scientists do not know how that carbon is separated between the brine versus solid and gas phases.

Dr Miller’s research is particularly relevant to thermohaline circulation and climate change modeling. If sea ice brine does transport carbon dioxide into the oceans depths, it constitutes a natural atmospheric sink that is not used in models at present.  At the same time, North Atlantic deep water formation of the global thermohaline circulation is important in sequestering CO₂ from the atmosphere.  The rate of CO₂ uptake by the ocean can be used to determine whether changes are occurring in the thermohaline circulation. 

Experiments

To answer these questions, Miss Brown will deploy in situ sensors to monitor atmospheric, sea ice and seawater pCO_2.

She will also:

• Collect weekly ice core and brine water samples from first year ice
• Section and melt ice cores for analysis
• Prepare ice sample for analysis of total inorganic carbon, alkalinity, salinity and specific isotopes of carbon and oxygen (¹³C and ¹⁸O) once off the Ice Base
• Collect brine samples from holes drilled to different depths
• Analyse some brine samples immediately for salinity and pH values
• Prepare and store the rest of the brine samples for analysis on total inorganic carbon, alkalinity, salinity and specific isotopes of carbon and oxygen (as above) once off the Ice Base

Comparing data from the ice cores against the seawater samples will indicate the amount and rate these chemicals are draining into the water.

Outcomes

This research will gather valuable data over the winter/spring period – data that does not presently exist elsewhere. Through existing collaborations between the research group and the Canadian Centre for Climate Modelling and Analysis, the results from this study will contribute to modeling efforts in the efficiency of the thermohaline circulation and in sea ice biogeochemistry.

All data collected in this study will be permanently archived at the Institute of Ocean Sciences, which contributes to both the Canadian national data archive and the Carbon Dioxide Information and Analysis Center.

Researchers & universities:

Principal investigator: Dr Lisa Miller, Institute of Ocean Sciences, British Columbia, Canada

Ice Base researcher: Kristina Brown, Department of Earth and Ocean Sciences, University of British Columbia, Canada

Collaborating researchers & universities:

• Associate Professor Philippe Tortell, Department of Earth and Ocean Sciences, University of British Columbia, Canada
• Associate Professor Timothy Papakyriakou, Department of Enviroment and Geography, University of Manitoba, Canada
• Professor Roger Francois, Department of Earth and Ocean Sciences, University of British Columbia, Canada

Extreme Cooking

2010, Ice Base

4 Day Storm at Ice Base

2011, Ice Base