Current TOSST Interests

These are only suggested research topics for the TOSST program. Please feel free to bring your research ideas to us!

Fisheries – Western and Indigenous Knowledge Systems, Fish- WIKS

Canada’s fisheries decision-making processes have been unsuccessful, and the current hierarchical governance regime is at odds with stakeholder involvement in decision-making, particularly the growing legal recognition of Aboriginal and treaty rights and title. The research project examines the valuation, ownership, and control of knowledge, and will compare indigenous knowledge systems (IKSs) among distinct indigenous coastal communities in light of the western knowledge system underpinning governmental decision-making processes. Research will examine the extent to which western and indigenous knowledge systems influence fisheries governance at multiple levels and how distinct IKSs can improve current efforts, given the complexities of ecosystems and uncertainties posed by climate-induced changes.

Please contact Prof. Lucia Fanning for more information.

Stable isotope measurements on CO2 and N2O from Volunteer Observing Ships

The objective is to better understand the full annual cycle of CO2 and other gases in North Atlantic surface waters using an isotopic analyser based on cavity ring- down spectroscopy (CRDS) analyzer installed on a commercial vessel (Atlantic Companion) that transits monthly between Hamburg and Halifax as well as on an offshore supply vessel (Atlantic Condor) that transits the Scotia Shelf off Halifax weekly. The seasonal variability of isotopic compositions of CO2 traces mass flow between different carbon reservoirs, e.g. biological uptake and release, mixing, and gas exchange. Collaborative testing of this new analytical approach serves as a first step toward replacing conventional CO2 observation systems with systems allowing simultaneous measurement of CO2 and its C- and O-isotope composition. Extension of to isotopic measurement of N2O would allow for study of nitrogen-containing compounds (in cooperation with Picarro Inc.).

Please contact Prof. Douglas Wallace for more information.

Effects of atmospheric nutrient delivery on marine productivity at the ocean’s surface

Atmospheric deposition of nitrogen, iron, and phosphorus has major implications for marine productivity. However, considerable uncertainty remains about the deposition flux of these nutrients from the atmosphere to the ocean, and their relative importance in different regions. The past decade has seen dramatic developments in capabilities of global modeling, satellite remote sensing, and in situ measurements of atmospheric and oceanic composition, in part through contributions from members of the TOSST team. These tools will be combined to improve estimates of this important nutrient flux, and its effect on marine productivity.

Please contact Prof. Randall Martin for more information.

Sedimentary records of past ocean and climate change in the N. Atlantic

Understanding the ocean’s past variability is required for establishing a longer term ‘background’ state against which anthropogenic influences can be measured. This project will use selected proxies or tracers to extend the (sparse) historical records of ocean and climate variability in the N. Atlantic to the last millennium, and beyond. For instance, we will calibrate and apply to down-core records: i) biomarker composition, as a record of past sea surface temperature variability and sea ice distribution; ii) siliciclastic grain size distributions, as proxy of the degree to which deep-sea sediments have been reworked by currents, i.e. as paleo-current meters; and iii) sedimentary nitrogen isotopes, as recorders of past changes in nutrient availability and consumption.

Please contact Prof. Markus Kienast or Prof. Stephanie Kienast for more information.

Interdependencies of observed changes in predator and plankton abundance

Students will collaboratively use large mesocosms (medium-sized biological communities) at GEOMAR in Kiel to test whether climate warming is a major factor in observed declines in phytoplankton abundance, and how it may affect the rest of the food web, including fish. Newly developed statistical tools for tracking fish stock abundance and productivity in response to both changes in fishing and resource availability will also be used to understand how living resources are affected. Finally, these results will be used in the development of global ecosystem models that include important ecological interactions and provide the capacity to predict future changes in the composition and functioning of marine ecosystems.

Please contact Prof. Boris Worm for more information.

The Acoustics of Hydrothermal Vents

The objective of the proposed work is to measure the spatial, temporal and spectral properties of the acoustic noise generated by hydrothermal vents. The noise data set will provide insight into the sound source mechanisms and estimates of source levels and frequency dependent source directionality. These acoustic properties can be used to determine the physical mechanisms of sound generation in hydrothermal vents. The basic understanding of the noise sources would then be used to determine the feasibility of passive acoustic detection of new vent sites. The long-term goals of this research include the development of passive acoustic localization techniques and physical and acoustic models allowing for the inversion of vent properties (flow rate, vent structure, vent fluid temperature and density) from noise measurements.

Please contact Prof. David Barclay for more information.

Control of open ocean CO2 uptake by shelf-generated alkalinity

Alkalinity can be considered as the biogeochemical bridge between different times scales, since the weathering of rocks in the terrestrial compartment of the Earth system produces alkalinity, a process that is in equilibrium with rock formation at geological times scales. Alkalinity is exported via rivers into the open oceans, where in turn it sets the background conditions for CO2 concentrations in the oceans, and thus CO2 air-sea exchange at present. Alkalinity is also produced during anaerobic respiration of organic matter in shelf and coastal seas at seasonal time scales. Two of the largest tidal mud flat areas border the North Atlantic Ocean on either side, the Bay of Fundy and the Wadden Sea. In this project we will investigate the impact that shelf generation of alkalinity has on the capacity of the open Atlantic to take up CO2.

Please contact Prof. Helmuth Thomas for more information.

Population connectivity in deep-sea ecosystems

Increasingly, anthropogenic activities (e.g. fishing, mining) are extending into the deep sea, and their impacts are predicted to act synergistically with climate change and increase over the next few decades. The level of exchange of individuals (“population connectivity”) among different locations (e.g. exploited vs. undisturbed) can influence how effectively populations and species can be maintained in the face of disturbance, or how quickly they can reoccupy areas after localized extirpation. The goal of this project is to understand the factors that regulate population connectivity in different systems, including hydrothermal vents, seamounts and deep-water corals, which ultimately will inform decisions on the sustainable management of these unique habitats.

Please contact Prof. Anna Metaxas for more information.

Development of an automated sea-going sampler for genetic analysis of microbial communities

Sampling the diversity and function of key microbial communities is now possible through the advancement of gene detection techniques and highthroughput sequencing. However, limitations involving sample collection at sea and the subsequent extraction of the nucleic acids back in the laboratory are currently the major bottlenecks preventing high-throughput characterization of oceanic microbial communities at the genetic level. This project will involve the development, testing and application of an automated sampler that collects and preserves samples at sea (e.g. from Volunteer Observing Ships) for flow cytometry and nucleic acid extraction back in the laboratory.

Please contact Prof. Julie Laroche for more information.

Development of State-of-the-Art Ocean Observation Systems

Over the last decade, marine robots have transformed ocean observation. They can support diverse suites of advanced sensors to resolve interacting physical, chemical, biological, and geological (sedimentary) phenomena. This project will develop advanced capabilities in marine robots that would allow missions for ocean observations, not a priori scripted. Such capabilities would be used in localizing the origin of a tracer material or substance (e.g. the source of an upwelling), adaptive sampling to intelligently and fully capture an evolving phenomenon (e.g. harmful algal blooms), or cooperation between multiple marine robots networked for autonomous observation and monitoring over large areas.

Please contact Prof. Mae Seto for more information.

Nitrogen dynamics and hypoxia in coastal regions

Over the past several decades, human activity has increased the input of dissolved nitrogen (nitrate, nitrite, and ammonium) to coastal waters. Because nitrogen is often a limiting nutrient in aquatic systems the resulting increase in primary production and subsequent deposition can lead to O2 depletion at depth and the development of hypoxic or even anoxic conditions.  These low oxygen environments are regions of intense redox-driven nitrogen cycling, resulting in potentially positive or negative feedbacks upon the eutrophication above.  A complete understanding of these feedbacks requires understanding the interactions between the physical, biological, and chemical processes occurring. This project will investigate these feedbacks in Bedford Basin, Halifax, NS. The basin is a predominately stratified, hypoxic basin, except when periods of wind-driven deep water renewal remove hypoxia by flushing with oxygen rich water. These periods of deep water renewal make the basin an ideal location to study transient nitrogen dynamics in low oxygen environments. The proposed project will focus on developing a bio-physical model to describe these processes within the Basin, including the effects of nitrogen isotope fractionation, and benthic-pelagic coupling. The perspective student should have an interest in mathematical modelling and biogeochemical cycles.

Please contact Prof. Chris Algar for more information.

Trade-offs in the design of networks of marine protected areas

The project examines the relative importance of population connectivity relative to other ecological selection criteria and its added benefits in the design of networks of marine protected areas. The project will include a cost-benefit analysis based on a critical evaluation of the inclusion (or not) of connectivity in existing management interventions, as well as in theoretical studies. An assessment will be done of ecological benefits (e.g. recruitment, viable population sizes, larval exchange and adequate gene flow) of including population connectivity as a selection criterion for the achievement of the conservation goals. In collaboration with its developers (University of Queensland), the ways in which an existing spatial planning tool (Marxan) utilizes connectivity in the algorithms will be expanded. Marxan will be used to evaluate the tradeoffs in current MPA selection, using Canadian test cases.

Positions available: 1 January to 1 May 2016

If interested, send CV, names of referees and statement of interest to metaxas@dal.ca

Candidates are expected to be competitive (and apply) for external scholarships.