Implications of climate change for northern Canada: freshwater, marine, and terrestrial ecosystems.

Climate variability and change is projected to have significant effects on the physical, chemical, and biological components of northern Canadian marine, terrestrial, and freshwater systems. As the climate continues to change, there will be consequences for biodiversity shifts and for the ranges and distribution of many species with resulting effects on availability, accessibility, and quality of resources upon which human populations rely. This will have implications for the protection and management of wildlife, fish, and fisheries resources; protected areas; and forests. The northward migration of species and the disruption and competition from invading species are already occurring and will continue to affect marine, terrestrial, and freshwater communities. Shifting environmental conditions will likely introduce new animal-transmitted diseases and redistribute some existing diseases, affecting key economic resources and some human populations. Stress on populations of iconic wildlife species, such as the polar bear, ringed seals, and whales, will continue as a result of changes in critical sea-ice habitat interactions. Where these stresses affect economically and culturally important species, they will have significant effects on people and regional economies. Further integrated, field-based monitoring and research programs, and the development of predictive models are required to allow for more detailed and comprehensive projections of change to be made, and to inform the development and implementation of appropriate adaptation, wildlife, and habitat conservation and protection strategies.

Using adaptive processes and adverse outcome pathways to develop meaningful, robust, and actionable environmental monitoring programs.

The primary goals of environmental monitoring are to indicate whether unexpected changes related to development are occurring in the physical, chemical, and biological attributes of ecosystems and to inform meaningful management intervention. Although achieving these objectives is conceptually simple, varying scientific and social challenges often result in their breakdown. Conceptualizing, designing, and operating programs that better delineate monitoring, management, and risk assessment processes supported by hypothesis-driven approaches, strong inference, and adverse outcome pathways can overcome many of the challenges. Generally, a robust monitoring program is characterized by hypothesis-driven questions associated with potential adverse outcomes and feedback loops informed by data. Specifically, key and basic features are predictions of future observations (triggers) and mechanisms to respond to success or failure of those predictions (tiers). The adaptive processes accelerate or decelerate the effort to highlight and overcome ignorance while preventing the potentially unnecessary escalation of unguided monitoring and management. The deployment of the mutually reinforcing components can allow for more meaningful and actionable monitoring programs that better associate activities with consequences. Integr Environ Assess Manag 2017;13:877-891. © 2017 The Authors. Integrated Environmental Assessment and Management Published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Surface metal adsorption on zooplankton carapaces: implications for exposure and effects in consumer organisms.

The current study aimed to determine the potential of two important aquatic invertebrate crustacean species, Daphnia magna and Ceriodaphnia dubia, to adsorb cadmium on to their carapaces from aqueous solution. Using the Langmuir equation to model data outputs, it was shown that cadmium readily became associated with the carapace surfaces of both species, with uptake being dependent on exposure time and concentration. Maximum carapace-adsorption potential was found to be directly related to surface area, so that at predicted carapace saturation, D. magna neonates bound approximately five times more cadmium than the smaller C. dubia neonates. However, adsorption per unit surface area was found to be similar under the same exposure conditions. Results of surface metal adsorption studies in C. dubia suggested that short term exposures to high concentrations of aqueous cadmium would lead to similar levels of adsorption as obtained with long-term exposures to low concentrations. The study illustrates that contaminants adsorbed to prey surfaces may be an important mechanism of exposure to predators, and highlights some potential problems of feeding organisms during long-term toxicity tests.

Northern Rivers Ecosystem Initiative: nutrients and dissolved oxygen - issues and impacts.

Anthropogenic inputs of nitrogen (N), phosphorus (P) and oxygen-consuming material to aquatic ecosystems can change nutrient dynamics, deplete oxygen, and change abundance and diversity of aquatic plants and animals. The Northern Rivers Ecosystem Initiative required a research and assessment program to establish the contribution of pulp mill and sewage discharges to eutrophication and depressions in dissolved oxygen (DO) in the Athabasca and Wapiti rivers of northern Alberta, Canada and examine the adequacy of existing guidelines for protecting these systems. Analysis of long-term data showed that total N (TN) and total P (TP) concentrations in exposed river reaches exceeded concentrations in reference reaches by < or = 2 times for the Athabasca River, and by 9.6 (TP) and 2.6 (TN) times for the Wapiti River. Results from nutrient limitation experiments conducted in situ and in mesocosms showed that benthic algal production was nutrient sufficient downstream of pulp mill discharges but constrained in upper river reaches by insufficient P (Athabasca River) or N + P (Wapiti River). Dissolved oxygen (DO) concentrations in both rivers declined during winter such that median concentrations in the Athabasca River 945 km downstream of the headwaters were approximately 8 mg L(-1) in mid-February. Although water column DO rarely approached the guideline of 6.5 mg L(-1), DO studies undertaken in the Wapiti River showed that pore water DO often failed to meet this guideline and could not be predicted from water column DO. Results from this integrated program of monitoring and experimentation have improved understanding of the interactions between nutrients, DO and aquatic ecosystem productivity and resulted in recommendations for revisions to nutrient and DO guidelines for these northern rivers.