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BIO Coffee Talks: November 2018

Who: Thor Klevjer

Institute of Marine Research, Bergen, Norway

What: Ecology and Management of an Antarctic Hotspot

The distribution of catches from the krill fishery in the Atlantic sector of the Southern Ocean shows that this fishery is increasingly contracting spatially into a few small areas. These areas are all relatively close to land, and are also "hotspots" of avian, pinniped and cetacean activity for at least parts of the year. There is concern about the potential for negative interactions between the fishery and the natural krill predators, and the regulatory body CCAMLR is actively seeking to improve management strategies for the Southern Ocean. Norway is in the process of extending its monitoring efforts in one of these hotspots, the area around the South Orkney Islands, by deploying acoustic moorings in the commercially exploited area. Data gathered from the moorings will be used to study the ecological dynamics of this hotspot. Empirical data will also feed into physically coupled krill models, which will be used to gain better understanding of the interaction between ocean physics and krill behaviour in driving krill biomass variation in the area. The full deployment is scheduled for February 2019, but we already have a few years of data from a reduced set of moorings (ADCP, narrowband and wideband echosounders), so some preliminary data will be presented.

The Norwegian project is ultimately aimed toward fishery management, but the underlying ecological questions being studied is why some marine areas are more important to top predators than others.There is probably significant overlap in focus with Canadian projects on the North Atlantic right whale, and there could be opportunities for collaboration.

When: Friday, November 30, 2018

Where: 10am, Needler Boardroom, Bedford Institute of Oceanography, Dartmouth, Nova Scotia


Who: Xianyao Chen

Key Laboratory of Physical Oceanography, Ocean University of China

What: Variability of the Atlantic Overturning Circulation and its impact on Global Surface Warming

In the presence of top-of-atmosphere (TOA) radiative imbalance, the earth's surface could have warmed much more rapidly were it not for the buffering role of the deep oceans. Here we describe and quantify one of the effective mechanisms for ocean heat sequestration and its variability: the Atlantic meridional overturning circulation (AMOC) that spans both hemispheres, and is responsible for sequestering about half of the excess heat globally during one of its phases. A picture of how AMOC varies through one complete cycle emerges. After a relatively stable low phase 1975-1998, AMOC sped up rapidly, and then declined rapidly from the 2005 peak to the present. During the stable low phase, the Atlantic did not sequester additional heat, and the TOA radiative imbalance manifested itself mainly at the surface, as rapid global warming for 25 years. This concept of rapid surface warming during a period of low AMOC runs counter to the common perception based on preindustrial data, which becomes inapplicable when there is TOA forcing. The direct observation of AMOC is extremely difficult. Further evidence from other potential proxies are needed to test this hypothesis for the extended record of AMOC variability.

When: Friday, November 16, 2018

Where: 10am, Needler Boardroom, Bedford Institute of Oceanography, Dartmouth, Nova Scotia


Who: Erica Head

Fisheries and Oceans Canada, Bedford Institute of Oceanography

What: Variations in Calanus finmarchicus life history in the Northwest Atlantic and the enigma of the Central Labrador Sea

Calanus finmarchicus occurs throughout the North Atlantic north of the Gulf Stream, where its various life history stages are food for the larvae, juveniles and/or adults of numerous fish species (e.g. cod, haddock, capelin, mackerel, herring), some sea birds (e.g. dovekies, phalloropes) and mammals: notably the Northern Right Whale. In Canadian waters, C. finmarchicus has an annual life-cycle, with individuals overwintering at depth as pre-adult stage five copepodites (CVs), ascending to the surface as adults in spring, feeding on the phytoplankton bloom and releasing eggs into the water. The eggs that survive develop through 12 life history stages, returning to depth to overwinter as CVs in late summer/fall. The timing and rate of reproduction, the rate of development, the size of each year's generation and the timing of descent are influenced by variables that include temperature, spring bloom dynamics and mortality. In this talk, C. finmarchicus life histories will be examined at five locations in the Northwest Atlantic: two on the continental shelf and three in the Labrador Sea. The Labrador Sea is an important population centre for C. finmarchicus and an upstream source to the Canadian continental shelf waters, but its central basin presents an enigma, in that its C. finmarchicus population does not appear to be self-sustaining over much of its area.

When: Friday, November 9, 2018

Where: 10am, King Boardroom, Bedford Institute of Oceanography, Dartmouth, Nova Scotia


Who: Dustin Whalen

Geological Survey of Canada, Natural Resources Canada

What: The Acceleration of Coastal Change in the Beaufort Sea: What does it mean to communities, ecosystems and marine life?

The coastline of the Inuvialuit Settlement Region in the Mackenzie-Beaufort region of the western Canadian Arctic is characterised by rapid erosion of ice-bonded sediments with abundant excess ground ice, resulting in widespread landward retreat of shorelines. Much of the coastline is known to be eroding at long-term rates of 1-2 m/yr (with rates in excess of 35 m/yr in some places). The acceleration of coastal change over the past two decades has sparked the need for not only a better understanding of coastal dynamics, but also a better understanding of the potential impacts this landscape change could have on communities, and vulnerable nearshore ecosystems. To do this the Geological Survey of Canada has deployed unmanned aerial vehicles (UAVs) at selected sites (ie. Hamlet of Tuktoyaktuk), combined with a series of instrumented moorings, sediment samples and sonar surveys to look at coastal erosion, sediment transport and sedimentation in the nearshore environment.

When: Friday, November 2, 2018

Where: 10am, King Boardroom, Bedford Institute of Oceanography, Dartmouth, Nova Scotia


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Last Modified: 2018-12-05