Locations and Dates:
Jan. 22 12pm (StFX)
Jan. 23 11:30am (Dal)
The future of Arctic sea ice and primary production in a changing climate: insights from the past
As the Arctic warms, the thickness, duration and extent of the sea-ice cover decline. The effects of a dwindling sea ice cover have already been associated with changes in the functioning of marine ecosystems. Changes in sea ice notably impact primary producers — the photosynthetic organisms that provide the initial source of food to higher organisms. Sea ice not only imposes energetic constraints to primary producers, it also strongly influences the physical and chemical properties of the water in which they grow. Given the complex interplay of factors that control primary production, determining the direction and magnitude of future changes in Arctic primary production in a scenario of continued climate warming is challenging.
The Holocene (last 11 000 years) was marked by several natural transitions from colder to warmer episodes. Investigating the long-term records of climate and productivity change preserved in marine sediment covering the last millennia can thus represents a valuable way to assess the impact of climate-induced environmental changes on productivity regimes. Here, I will discuss how a combination of methods based on the study of microfossils, biomarkers and geochemical tracers can be used to interpret past fluctuations in sea ice cover and their linkage to primary production.
Audrey Limoges is a micropaleontologist interested in the impact of climate changes on sea ice, ocean circulation and primary production. Her PhD research (Geotop, UQAM) was focused on the use of microfossils and toxins as tracers of harmful algal blooms and sea-surface conditions in the Gulf of Mexico. Her research shifted to the Arctic during a postdoc at the Geological Survey of Denmark and Greenland, after which she took up an assistant professorship at University of New Brunswick, Fredericton. Her most recent research activities focus on the methodological aspects, the calibration and application of diverse biogenic sedimentary proxies (e.g. microfossils, geochemical tracers, biomarkers) for the reconstruction of past environmental conditions in northern Baffin Bay and Hudson Bay.
Locations and Dates:
Nov. 18 (11:30 am) SMU
Nov. 19 (12:00 pm) Acadia – Huggins Science Building
Nov. 20 UNB-F
Ore-forming processes on the seafloor – understanding the difference between black smoker vent fields and the formation of metal-rich massive sulfide mineral deposits
Since the initial discovery of black smokers on the East Pacific Rise in 1979 a significant amount of research and exploration efforts has focused on finding and studying active seafloor hydrothermal systems along submarine tectonic boundaries. The evolution of exploration methodologies and development of new marine survey technology has advanced to the point where the discovery of new vent fields is becoming routine. This increasing rate of discovery coincides with increasing interest to mine the metal-rich seafloor massive sulfide (SMS) deposits that can form at hydrothermal vents. To properly evaluate the resource potential and environmental consequences of mining SMS deposits, it is important to recognize that not all seafloor hydrothermal systems are necessarily ore forming systems that are metal-rich and have generated, or are generating, SMS deposits of large-enough size to be economically-viable targets for mining. Despite significant promotion and debate surrounding seafloor mining, exploration and sampling efforts indicate that very few of the ~400 seafloor massive sulfide deposits discovered to date are economically feasible targets. In most cases, there simply is not enough information at the deposit scale for a proper evaluation of either grade or tonnage. Where grades and tonnages for SMS deposits have been reported, they are often based on assumptions regarding the composition of the subseafloor material that makes up the bulk of these deposits. In this talk I will present examples of the striking variability in composition of hydrothermal deposits along the Mid-Atlantic Ridge and discuss why not all deposits that accumulate at high-temperature hydrothermal vent fields are necessarily ore-forming seafloor massive sulfide deposits.
Dr. John Jamieson is the Canada Research Chair in Marine Geology at Memorial University of Newfoundland where he has been since 2016. He did a B.Sc. at the University of Alberta, and MSc at the University of Maryland, and his PhD at the University of Ottawa where he worked with Dr. Mark Hannington. Between his B.Sc. and M.Sc., and then after M.Sc. he worked for two years in the Arctic doing gold exploration with Cumberland Resources. He spent 2 years at the Alberta Geological Survey, where he ran their metallic minerals program, and did a 2-year post-doc at GEOMAR at the Helmholtz Center for Ocean Research, in Kiel, Germany. His current research focuses on seafloor hydrothermal systems, ocean exploration, and marine mineral resources. He has participated in 14 research cruises, and to date has spent over 400 days at sea.