MAINSTREET NS | Sep 30th, 2014
MAINSTREET NS | Sep 9th, 2014
MAINSTREET NS | Aug 19th, 2014
MAINSTREET NS | Apr 16, 2013
Declining productivity of cod stocks
Productivity is a central determinant of population dynamics with consequences for population viability, resilience to exploitation, and extinction. In fish, the strength of a cohort is typically established during early life stages. Traditional approaches to measuring productivity do not allow for interannual variation in the maximum reproductive rate, a parameter governing population productivity. Allowing such process variation provides the ability to track dynamic changes instead of assuming a static productivity regime. Here we develop and evaluate a multivariate stockârecruitment state-space model to simultaneously estimate time-varying stock productivity and synchronicity of dynamics across populations.
DetailsMAINSTREET NS | May 27, 2014 | 8:24
Long-term trends in ocean chlorophyll
Marine phytoplankton account for approximately half of the production of organic matter on earth, support virtually all marine ecosystems, constrain fisheries yields, and influence climate and weather. Despite this importance, long-term trajectories of phytoplankton abundance or biomass are difficult to estimate, and the extent of changes is unresolved. Here, we use a new, publicly-available database of historical shipboard oceanographic measurements to estimate long-term changes in chlorophyll concentration from 1890 to 2010.
DetailsEffects of sea surface warming on marine plankton
Ocean warming has been implicated in the observed decline of oceanic phytoplankton biomass. Some studies suggest a physical pathway of warming via stratification and nutrient flux, and others a biological effect on plankton metabolic rates; yet the relative strength and possible interaction of these mechanisms remains unknown. Here, we implement projections from a global circulation model in a mesocosm experiment to examine both mechanisms in a multi-trophic plankton community.
DetailsNSERC Presents 2 Minutes with Boris Worm
Dalhousie University’s Boris Worm combines oceanography and marine biology to paint a more complete picture of what’s happening under the waves. Comprehensive information about the state of the oceans leads to better fisheries management, which benefits the environment, the economy and society as a whole.
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