Halifax: 19th - 21st October, 2015

VITALS
Ventilation, Interactions and Transports Across the Labrador Sea

Labrador Sea Satellite image

The VITALS (Ventilation, Interactions and Transports Across the Labrador Sea) research network will answer fundamental questions about how the deep ocean exchanges carbon dioxide, oxygen, and heat with the atmosphere through the Labrador Sea. New observations and modelling will determine what controls these exchanges and how they interact with varying climate, in order to resolve the role of deep convection regions in the Carbon Cycle and Earth System.

VITALs is a pan-Canadian initiative involving scientists from 11 Canadian universities as well as multiple federal government laboratories (Fisheries and Oceans Canada, as well as Environment Canada), industrial and foreign partners.

Research Goal

To understand and model the functioning and vulnerability of the Labrador Sea as a key component of the earth's climate system, including its uptake of oxygen, anthropogenic carbon, and exchange of heat with the atmosphere.

This video is also available in French

Hypothesis

Deep convection in the Labrador Sea, which allows for exchange of oxygen and natural and anthropogenic carbon to the deep ocean, is sensitive to the warming that is taking place at high latitudes.

Validating and quantifying this sensitivity is central to our research network and also the broader community of climate change researchers and policy makers interested in characterizing, and possibly minimizing, the effects of global climate change.

Scientific Rationale

To understand and model the functioning and vulnerability of the Labrador Sea as a key component of the earth's climate system including its uptake of oxygen, anthropogenic carbon, and exchange of heat with the atmosphere.

We will measure oxygen, carbon dioxide and other climate-relevant gases over several seasonal cycles, characterize their temporal and spatial variability in the Labrador Sea, and determine the factors controlling their uptake, storage and appropriate physics and flexibility to simulate their evolution in a changing climate. We will tie the understanding developed to models of global climate change through the study of one of the few areas in the world, and the only one near Canada, that directly links three important reservoirs within the carbon cycle - the atmosphere, the upper ocean and the deep ocean. Within this high-profile internationally linked study we will highlight the strengths of the Canadian marine technology industry, by showcasing the latest advanced developments of several Canadian companies in our field program.

Our working hypothesis is that deep convection in the Labrador Sea, which allows for exchange of oxygen and natural and anthropogenic carbon to the deep ocean, is sensitive to the warming that is taking place at broader community of climate change researchers and policy makers interested in characterizing, and possibly minimizing, the effects of global climate change.

Motivation

In the Labrador Sea and adjacent seas, the atmosphere, surface ocean, and deep ocean interact in complex ways involving the interplay of physical, chemical, and biolog ical processes. These interactions are poorly understood and actively evolving under changing climate conditions. We are motivated by these uncertainties in a key deep convection region to make new observations that will produce improved parameterizations for future climate prediction.

The Labrador Sea is characterized by a biological cycle that seasonally exchanges large amounts of carbon between the atmosphere, surface ocean and deep ocean and is also an important site for anthropogenic carbon uptake by the ocean. In addition, the oxygen cycle in the Labrador Sea is changing as rising temperatures lower gas sol ubility and perturb respiration and production rates (Keeling and Garcia 2002). Photosynthesis during the productive spring bloom and summer months creates a deficit of CO2 in the surface that causes an uptake of CO2 from the atmosphere. The organic carbon created by this process sinks and is respired in deeper waters, leading to CO2 excess in the subsurface that can drive a flux into the atmosphere during wintertime deep convection. At present, the net impact on atmospheric CO2 is unclear, and resolving this issue is one goal of the proposed work. The biophysical interactions that initiate the bloom and the dominance of different phytoplankton functional groups influence this natural biological carbon pump and climate (Frajka-Williams et al. 2009). Anthropogenic emissions of CO2 perturb the natural air-sea flux and result in a growing ocean total CO2 uptake (Takahashi et al. 2009).

Regions like the Labrador Sea that act as a conduit to the interior ocean are particularly important to anthropogenic carbon uptake and storage in the ocean (Sabine et al. 2004). One expectation of a warmer climate is a slowing of Labrador Sea Water formation, a shoaling of the penetration depth of anthropogenic carbon, and a weakening of the ocean sink for anthropogenic CO2 (Steinfeldt et al. 2009). On the other hand, a slowdown in deep water formation, is also thought to allow biological carbon to accumulate at depth, possibly counterbalancing the slowdown in anthropogenic CO2 uptake.

Understanding the interaction of the natural cycle with the anthropogenic overprint and how each will change is imperative to modelling and predicting the global carbon cycle. Once deep water forms in the Labrador Sea, it is further transformed before being exported into the rest of the ocean. We need to quantify the vertical and horizontal exchanges of mass, freshwater, carbon, and oxygen to understand and model this process. The vertical exchanges determine the depth of CO2 storage and oxygen renewal, while the horizontal exchanges smooth property gradients between the interior and the boundary (Palter et al. 2008; Straneo et al. 2003). Re-stratification of newly for med deep Labrador Sea Water is eddy-driven (Lilly et al. 2003), and the re-stratifying eddies influence biological processes (e.g. initiation of the spring bloom - Frajka-Williams and Rhines 2010). The relative importance of circulation, mixing, and biological production and decomposition in redistributing carbon, oxygen, and nutrients in the Labrador Sea and triggering climate feedbacks are open questions that further motivate our proposal. The proposed work will tackle all of these processes, enhan cing our understanding of the cycle of convection and re-stratification and their impact on ocean-atmosphere heat and gas exchange, ultimately strengthening our numeri cal models and improving climate predictability.

Anticipated Benefits of Research

  • VITALS focuses on developing a mechanistic understanding of processes (carbon/oxygen cycles, lateral exchange) in a region of global importance on Canada's doorstep.
  • Our hierarchy of modelling approaches will significantly improve our understanding of the Labrador Sea and its role in climate
  • New observations will allow us to observe the evolution of the physical and biogeochemical properties over much of the water column for two annual cycles, buildin g on decades of observations constrained either to a single position in the water column or a snapshot of a profile over time.
  • Novel sampling strategies and approaches, including data mining of three decades of historical data, will lead to a greater understanding of processes that are hi ghly variable in space and time.
  • Canadian expertise is primed to lead and contribute to international initiatives within the region. International involvement will allow us to leverage our progra m for greater returns and significant cost savings, with more effective use of infrastructure and broader training opportunities for HQP.
  • VITALS synergistically partners with and builds upon existing long-term DFO Labrador Sea programs to provide a detailed understanding of processes for use by DFO in management decisions
  • This programs links, but does not overlap with, other major Canadian initiatives such as MEOPAR, CERC, HMRI and ArcticNet.
  • The central mooring will use unique Canadian technology and Canadian physical/biogeochemical sensors to provide a high-visibility showcase of advanced ocean techn ology and allow for technology transfer to Canadian companies, as well as improved international visibility of unique Canadian products.