The oceans dominate and define our planet, but remain largely unexplored. The research carried out in areas 1 and 2 will have increased pertinence and impact if observation technologies in the marine environment are further developed; if knowledge of the processes that regulate water and ice circulation is broadened; and if the ecology of marine organisms and the flows of matter and energy in the ocean and the interfaces surrounding the marine environment are better understood. In this regard, Québec-Océan’s teams are focusing on 5 sub-themes.

3.1. Circulation, eddies and turbulence
The movement of water masses on various scales can be induced, modified or constrained by a variety of factors, which include tides, wind, terrestrial rotation, ice, differences in temperature and salinity, inflows of fresh water in coastal environments or from seasonal ice cover, sediment load and aquatic vegetation. These factors make circulation complex, unstable and thus very variable and still difficult to forecast. This high variability, which extends from the scales in millimetres that characterize turbulence to scales in thousands of kilometers for the largest oceanic eddies, must be better understood if we are to improve forecasts of currents, ice movements, climate and interactions between the physical, chemical and biological processes involved. By affecting the horizontal and vertical dispersion of heat, salt, essential nutrients, gases and contaminants, eddies and turbulence have an influence on deepwater ventilation (O2 and CO2) and on the biological productivity of the marine environment.

The team is working to understand the fundamental mechanics of the oceans by using measurements made at sea, laboratory experiments, digital models and new theories. Among the subjects under study are waves, eddies, mesoscale and submesoscale fronts, sea ice, turbulence, internal waves and convection in coastal and ocean environments.

3.2. Ecology and the life cycle of marine organisms
To understand the impact of human activities and global change on the availability of exploitable resources and biodiversity as well as the functioning and health of the marine ecosystem, it is important to better understand the behaviour of various key species, how they use the environment and how they respond to environmental fluctuations and changes. While some species have relatively fixed life cycles and behaviours that make them particularly vulnerable to change, others have great phenotypic plasticity or rapid evolutionary adaptation.

The team is studying and modeling the life cycles, physiology, diet, reproductive success, dynamics and genetics of populations, as well as the evolutionary ecology of several marine species, including macro-algae, invertebrates, fish and mammals, that have key roles in marine communities and food webs.

3.3. Essential element cycles related to biodiversity
A biogeochemical cycle is the pathway followed by an element in moving through the environment and includes the organisms that consume or recirculate that element. Since the global inventory of elements is fixed, an understanding of the cycles of the major elements that make up living matter and greenhouse gases or that limit the ocean’s biological productivity (e.g., nitrogen and iron) is indispensible. New discoveries regularly modify our understanding of these cycles and the importance of biodiversity for their functioning.

The team is studying and modeling the details of macro-element fluxes (e.g., carbon, nitrogen, sulfur, phosphorus, silicon) and micro-element fluxes (trace metals, e.g., iron, copper) in pelagic and benthic environments as they relate to the specific richness and functional composition of communities.

3.4. Matter fluxes at the interfaces of the marine environment
The vertical and horizontal processes that regulate the exchanges and transformations of matter at the boundaries that delimit the marine environment (e.g., earth/sea, water/sediment, water/ice and sea/atmosphere) are still little understood or quantified. In the first metres of the ocean’s surface, the photochemical processes related to solar radiation transform complex organic molecules into reactive and often volatile inorganic compounds (e.g., CO, CO2, DMS, N2O, NH3). The presence of thin microlayers with physicochemical properties and distinct microbial flora has an influence on these gases and their diffusion through the sea/atmosphere interface. The exchanges of material between water and sea ice (when present) are essential to maintaining communities that live in brine channels. When they are released in the spring, the communities and their metabolic products influence in turn the water column, while meltwater promotes the establishment of a summer microlayer. In coastal environments, waterways and shorelines are the source of several substances (nutrients, particulate matter and dissolved matter) that affect marine biological productivity and biodiversity, as well as the accumulation and dynamics of sediment on the seabed. By exchanging gases and nutrients with seawater, sediment acts on the chemical composition of the water and the atmosphere.

To better understand the functioning of interfaces and their ecological impacts, the team is studying the chemical and biological composition of the lower atmosphere, marine microlayers, brine channels and marine sediment.
  © Virginie Galindo

3.5. State-of-the-art technologies for observing the marine environment
Most of the ocean is hidden from us. Although most oceanographic research must be carried out from ships or coastal stations, the implementation of new methods make it possible to broaden the scope of our observations and increase the required spatial and temporal resolution. These methods include remote sensing (satellites, acoustic sensing and high-frequency radar) and the deployment of autonomous devices equipped with sensors that collect data on the physical, chemical and biological structure of the ocean.

The team is developing new algorithms to better use remote sensing data as well as acquiring and adapting profiling buoys, gliders, autonomous submersibles and aerial unmanned vehicles to increase observation capabilities and ecological monitoring.
  © Doug Barber