Spatial patterns of sediment contamination and their influence on benthic infaunal communities in a highly tidal and industrial estuary in Atlantic Canada.

Sediment contamination can be elevated in ports, harbours, and estuaries with legacies of exploitation, negatively impacting infaunal invertebrate communities. Saint John Harbour (45.25° N, 66.05° W), New Brunswick, Canada, is an active harbour with strong tides and a long history of human activity. To examine spatial patterns of sediment contamination, samples were collected between 2011 and 2021 from subtidal sites near potential contaminant sources. Invertebrate data from the same samples were used to investigate potential effects on biological communities. Contaminant concentrations in the inner parts of the harbour were elevated compared to reference sites, but generally did not reach levels comparable to other highly contaminated harbours in the region. Effects on invertebrates were detectable, particularly at sites with higher contamination, although physical factors (depth, sediment grain size) were more important. Dynamic tidal conditions in the harbour may reduce the accumulation of contaminants in subtidal sediments and their impacts on infaunal communities.

High-resolution freshwater dissolved calcium and pH data layers for Canada and the United States.

Freshwater ecosystems are biologically important habitats that provide many ecosystem services. Calcium concentration and pH are two key variables that are linked to multiple chemical processes in these environments, influence the biology of organisms from diverse taxa, and can be important factors affecting the distribution of native and non-native species. However, it can be challenging to obtain high-resolution data for these variables at regional and national scales. To address this data gap, water quality data for lakes and rivers in Canada and the continental USA were compiled and used to generate high-resolution (10 × 10 km) interpolated raster layers, after comparing multiple spatial interpolation approaches. This is the first time that such data have been made available at this scale and resolution, providing a valuable resource for research, including projects evaluating risks from environmental change, pollution, and invasive species. This will aid the development of conservation and management strategies for these vital habitats.