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.

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.

Temporal and Spatial Trends in Benthic Infauna and Potential Drivers, in a Highly Tidal Estuary in Atlantic Canada.

Infaunal invertebrate communities of coastal marine sediments are often impacted by human activities, particularly in harbours and estuaries. However, while many studies have attempted to identify the key factors affecting benthic infauna, few have done so for highly energetic tidal estuaries. Samples were collected over a decade (2011-2020) from a series of reference sites in Saint John Harbour (45.25° N, 66.05° W), a highly tidal estuary in the Bay of Fundy, Canada. These data were used to examine spatial and temporal trends in infaunal invertebrate communities and sediment properties and to determine the extent to which the biological patterns were driven by measured physical and chemical variables. There were substantial differences among sites in infaunal invertebrate abundance (median ranging from 688 to 13,700 individuals per square meter), infaunal species richness (median ranging from 8 to 22), and Shannon diversity (median ranging from 1.26 to 2.34); multivariate analysis also revealed variation in species composition among sites. Sediment contaminant concentrations also varied among sites, but differences tended to be smaller (e.g. median chromium concentrations ranging from 21.6 to 27.6 mg/kg). Sample contaminant concentrations were all below probable effect levels, and almost all below threshold effect levels (Canadian interim sediment quality guidelines), but relationships with biological data were still detectable. However, physical variables (depth, sediment characteristics) were better predictors of biological variables and community composition. These results confirm the importance of physical factors in shaping infaunal communities in soft-sediment habitats in tidally influenced coastal waters. Supplementary Information: The online version contains supplementary material available at 10.1007/s12237-023-01222-w.

Influence of coating type, colour, and deployment timing on biofouling by native and non-native species in a marine renewable energy context.

Biofouling on marine renewable energy devices presents engineering challenges for this developing sector, and has implications for the spread of marine non-native species (NNS) in coastal waters. This is particularly true at sites with abundant energy resource, little existing infrastructure, and few established NNS. Device coatings, such as antifouling paints, could reduce the risk of NNS spread. Settlement on coatings of various types and colours, representing those likely to be used on renewable energy devices, was assessed in the Orkney Islands, northern Scotland. Assemblage composition, but not overall biofouling cover, varied initially among different coloured surfaces, although differences decreased over time. Different coating types (an anticorrosive paint, a biocidal paint and a fouling-release coating) differed in biofouling abundance and composition for the full duration of the experiment. NNS were mostly, but not completely, absent from antifouling surfaces. These results can help informing antifouling strategies for the marine renewable energy industry.

Mini-review: effect sizes and meta-analysis for antifouling research.

It is widely recognised that findings from experimental studies should be replicated before their conclusions are accepted as definitive. In many research areas, synthesis of results from multiple studies is carried out via systematic review and meta-analysis. Some fields are also moving away from null hypothesis significance testing, which uses p values to identify 'significant' effects, towards an estimation approach concerned with effect sizes and confidence intervals. This review argues that these techniques are underused in biofouling and antifouling (AF) research and discusses potential benefits of their adoption. They enable comparison of test surfaces even when these are not tested simultaneously, and allow results from repeated tests on the same surfaces to be combined. They also enable the use of published data to explore effects of different variables on the functioning of AF surfaces. AF researchers should consider using these approaches and reporting results in ways that facilitate future research syntheses.

Marine antifouling performance of polymer coatings incorporating zwitterions.

Zwitterionic materials display antifouling promise, but their potential in marine anti-biofouling is still largely unexplored. This study evaluates the effectiveness of incorporating small quantities (0-20% on a molar basis) of zwitterions as sulfobetaine methacrylate (SBMA) or carboxybetaine methacrylate (CBMA) into lauryl methacrylate-based coatings whose relatively hydrophobic nature encourages adhesion of the diatom Navicula incerta, a common microfouling organism responsible for the formation of 'slime'. This approach allows potential enhancements in antifouling afforded by zwitterion incorporation to be easily quantified. The results suggest that the incorporation of CBMA does provide a relatively minor enhancement in fouling-release performance, in contrast to SBMA which does not display any enhancement. Studies with coatings incorporating mixtures of varying ratios of the cationic monomer [2-(methacryloyloxy)ethyl]trimethylammonium chloride and the anionic monomer (3-sulfopropyl)methacrylate, which offer a potentially lower cost approach to the incorporation of anionic and cationic charge, suggest these monomers impart little significant effect on biofouling.

Characterisation of the biofouling community on a floating wave energy device.

Wave energy devices are novel structures in the marine environment and, as such, provide a unique habitat for biofouling organisms. In this study, destructive scrape samples and photoquadrats were used to characterise the temperate epibenthic community present on prototypes of the Pelamis wave energy converter. The biofouling observed was extensive and diverse with 115 taxa recorded including four non-native species. Vertical zonation was identified on the sides of the device, with an algae-dominated shallow subtidal area and a deeper area characterised by a high proportion of suspension-feeding invertebrates. Differences in species composition and biomass were also observed between devices, along the length of the device and between sampling dates. This research provides an insight into the variation of biofouling assemblages on a wave energy device as well as the potential technical and ecological implications associated with biofouling on marine renewable energy structures.

Effects of distilled water rinsing on stable isotope ratios of acid-treated marine invertebrate (Paguridae) samples.

RATIONALE: Stable isotope ratios are widely used to infer trophic relationships, although a growing number of studies show that sample pre-treatments (such as acidification to remove carbonates) can cause changes in isotope ratios. Samples are often rinsed in distilled water after acidification, and we examine the effects of this step in particular on the isotope ratios of marine invertebrate samples. METHODS: Samples of whole hermit crabs (Paguridae) were subjected to one of three treatments: acidification using dilute hydrochloric acid without subsequent distilled water rinsing; acidification with rinsing; and rinsing with no acidification. Continuous-flow isotope ratio mass spectrometry was used to compare the mean carbon and nitrogen stable isotope ratios of treated and untreated material. RESULTS: Acidification (both with and without subsequent distilled water rinsing) resulted in reductions in mean δ(13)C values (1.939 and 3.146‰, respectively), while rinsing without prior acidification led to a smaller (but still significant) increase. Nitrogen isotope ratios were not affected by acidification, but subsequent rinsing with distilled water caused a decrease of approximately 1‰. CONCLUSIONS: Acidification of samples is clearly necessary in the presence of carbonates to obtain useful carbon isotope ratio data. However, post-acidification rinsing can result in further (potentially undesirable) changes to both carbon and nitrogen isotope ratios. Ideally, rinsing should be avoided, but the impacts are small enough to be of little concern in many studies. Rinsing (or not) should be considered carefully on the basis of the aims of a study.