Identifying transformational space for transdisciplinarity: using art to access the hidden third.

A challenge for transdisciplinary sustainability science is learning how to bridge diverse worldviews among collaborators in respectful ways. A temptation in transdisciplinary work is to focus on improving scientific practices rather than engage research partners in spaces that mutually respect how we learn from each other and set the stage for change. We used the concept of Nicolescu's "Hidden Third" to identify and operationalize this transformative space, because it focused on bridging "objective" and "subjective" worldviews through art. Between 2014 and 2017, we explored the engagement of indigenous peoples from three inland delta regions in Canada and as a team of interdisciplinary scholars and students who worked together to better understand long-term social-ecological change in those regions. In working together, we identified five characteristics associated with respectful, transformative transdisciplinary space. These included (1) establishing an unfiltered safe place where (2) subjective and objective experiences and (3) different world views could come together through (4) interactive and (5) multiple sensory experiences. On the whole, we were more effective in achieving characteristics 2-5-bringing together the subjective and objective experiences, where different worldviews could come together-than in achieving characteristic 1-creating a truly unfiltered and safe space for expression. The novelty of this work is in how we sought to change our own engagement practices to advance sustainability rather than improving scientific techniques. Recommendations for sustainability scientists working in similar contexts are provided.

Historical and Contemporary Patterns of Mercury in a Hydroelectric Reservoir and Downstream Fishery: Concentration Decline in Water and Fishes.

Mercury (Hg) contamination can pose risks to human and animal health as well as commercial fisheries. Reservoir construction in riverine systems produces flooded conditions amenable to Hg(II)-methylating bacteria, which can transform this relatively benign environmental contaminant into the bioaccumulative, environmentally relevant, and neurotoxic methyl-Hg (MeHg). Hg concentrations ([Hg]) in fishes from reservoirs can take decades to decrease to pre-dam levels, but less is known about Hg exported downstream and its dynamics within downstream fish populations. We examined and compared the multidecadal rates of biotic [Hg] decrease and contemporary factors affecting [Hg] in fish collected from a hydroelectric reservoir (Tobin Lake) and a related downstream fishery (Cumberland Lake) along the Saskatchewan River, Canada. Rates of [Hg] decrease were considered in four species-northern pike (Esox lucius), sauger (Sander canadensis), goldeye (Hiodon alosoides), and walleye (S. vitreus)-all of which showed a significant decrease over time (p < 0.001) and are now lower than Health Canada consumption guidelines (0.5 µg/g). Rates of decrease ranged from 0.5 to 3.9 %/year and were similar between sites in the cases of northern pike and sauger. Contemporary factors affecting [Hg] in walleye collected downstream include fish length (p < 0.001), fish age (p < 0.001), and trophic magnification through the food web (p < 0.001), and relationships between [Hg] and trophic level in predatory and prey fish are now similar to those found in non-Hg-inundated systems at a similar latitude. Together, these results suggest connected contamination between the two sites and delineate the timeline during which [Hg] in a variety of fish species decreased to nontoxic levels in both locations.