Harmful algae in the Strait of Georgia, citizen science data

The Citizen Science Program was initiated by the Pacific Salmon Foundation, Fisheries and Oceans Canada, and Ocean Networks Canada in 2015. This Program was designed to achieve oceanographic monitoring of the Strait of Georgia on temporal and spatial scale that had never been done before. Samples and measurements were taken at approximately 80 sites on a bi-monthly (or higher) frequency from February to October, 2015 to 2017. This presentation will be focused on the spatial and temporal distribution of harmful algae based on the analysis of about 5000 phytoplankton samples. Preliminary results indicate that during the sampling period in the Strait, there were no significant (\u3e1000 cells per mL) Heterosigma akashiwo blooms. Very high levels of Chaetoceros convolutus/concavicornis were recorded in spring 2015 in northern areas of the Strait. Low and moderate levels of non-skeletal Dictyocha were observed from June to August 2016 and during August 2017 at most of the sampling areas. Further work will include investigating relationships between harmful algae cell densities and environmental variables (nutrients, temperature, salinity, dissolved oxygen, turbidity, etc.). One of the major goals of the Program is to provide data aiding in assessing the potential effects of harmful algal blooms on the juvenile salmon survival in the Salish Sea

Influence of presowing seed treatment on the yield of variegated alfalfa and eastern galega

The article deals with the insufficiently studied problem of variegated alfalfa and eastern galega presowing seed treatment, which can serve as an excellent reserve for increasing their forage productivity. The quality of the seeds determines the stand density of perennial grasses and their yield. The studies have been performed on sod-podzolic medium loamy soil. The authors studied the effect of molybdenum-acid ammonium (300 gm/t), Rhizotorphine bacterial preparation (for variegated alfalfa – 0.5 l/t, for eastern galega – 1.0 l/t), HB-101 plant growth regulator (1 ml/t), and Agree's Forsage complex fertilizer (1.2 l/t) upon cultivating the studied crops. The consumption rate of the working solution (water + preparation) was 10 litres per ton of seeds. The accounting plot area was 33 m2. Perennial legumes were sown after spring rapeseed; the seeding rate for variegated alfalfa was 14 kg/ha, for eastern galega – 26 kg/ha. It has been found that introducing seed treatment with the Agree's Forsage complex fertilizer increases productivity by 23–47% due to increasing the field germination of variegated alfalfa by 10–15% and eastern galega by 4–10%, and due to increasing the number of nodule bacteria by 6–13 per plant and 8–16 per plant respectively

Seasonal dynamics of oceanographic conditions, phytoplankton, and zooplankton in the Malaspina Strait, Strait of Georgia

Plankton dynamics in the Salish Sea may directly impact resident and migratory fish populations that are of major economic importance in the region. The Malaspina Strait in the northern Salish Sea is of particular interest as it is an important migration route for juvenile salmon. Here, we present data collected at three stations in the Malaspina Strait as part of the Citizen Science initiative of the Salish Sea Marine Survival Project. Sampling was conducted at bi-monthly (or higher) frequency from February to October, 2015 to 2017. Relationships between the regional hydrography, environmental parameters (temperature, salinity, dissolved oxygen, etc.), nutrient concentrations, and phytoplankton and zooplankton community composition are considered. Preliminary results indicate that 2015 was an anomalous year with an earlier-than-average (mid-February) spring phytoplankton bloom. Phytoplankton community composition was dominated by centric, chain-forming diatoms in spring of all years, cell densities were higher in spring 2015 compared to 2016 and 2017. In both 2015 and 2016, copepods dominated the abundances of zooplankton at the deep locations in Malaspina Strait. However, the biomass was dominated by taxa known to be the preferred prey of juvenile salmonids (euphausiids, amphipods, crab larvae). At the nearshore station in both years, zooplankton biomass was dominated by “other” taxa, in particular gelatinous plankton. Biomass of large calanoid copepods and euphausiids was significantly positively correlated to the relative abundance of diatoms. Biomass of small calanoid copepods and non-calanoid copepods, on the other hand, was positively correlated with the relative abundance of dinoflagellates. Further analyses will relate environmental variables to the observed seasonal variations in phytoplankton and zooplankton. Results from this study will ultimately be extended to include other Citizen Science stations in order to gain a better understanding of how bottom-up processes vary in different regions of the Salish Sea, and the potential implications for higher trophic levels

Retention of radiation damage in zircon xenocrysts from kimberlites, Northern Yakutia

We have studied zircon xenocrysts from Mesozoic kimberlites from the Kuoika and Ary–Mastakh fields in Northern Yakutia. Zircon xenocrysts are assumed to originate from crustal rocks. Our SHRIMP (Sensitive High mass Resolution Ion MicroProbe) analyses yielded predominantly concordant U–Th–Pb ages (up to ~ 3570 Ma; Paleoarchean) that clearly predate kimberlite formation. The general U–Th–Pb concordance observed excludes notable disturbance of the zircon xenocrysts U–Th–Pb isotope system during kimberlite ascent and emplacement. In addition, zircon xenocrysts were found to be significantly more radiation-damaged than would correspond to damage accumulation only since the time of kimberlite formation. This observation first indicates that zircon crystals were sampled by the kimberlite magma at comparably shallow depths not exceeding 10–12 km. If, in contrast, zircon crystals originated from deeper levels of the Earth's crust, they would have been exposed to temperatures of 250–300 °C or more. This in turn would have caused long-term thermal annealing of the radiation damage, which was however not observed in our study. Second, our observation contradicts the hypothesis that high temperatures experienced by zircon xenocrysts during kimberlite ascent will cause notable structural reconstitution by short-term thermal annealing. Consequently, zircon crystals cannot have spent more than a few hours at temperatures exceeding ca. 700–800 °C, or more than a few days at temperatures exceeding ca. 500–600 °C. This in turn suggests that (i) temperatures of the ascending kimberlite magmas were rather moderate, and (ii) kimberlite ascent is a comparably short process followed by rapid cooling

Dinophysis toxins: Causative Organisms, Distribution and Fate in Shellfish

Several Dinophysis species produce diarrhoetic toxins (okadaic acid and dinophysistoxins) and pectenotoxins, and cause gastointestinal illness, Diarrhetic Shellfish Poisoning (DSP), even at low cell densities (<103 cells·L−1). They are the main threat, in terms of days of harvesting bans, to aquaculture in Northern Japan, Chile, and Europe. Toxicity and toxin profiles are very variable, more between strains than species. The distribution of DSP events mirrors that of shellfish production areas that have implemented toxin regulations, otherwise misinterpreted as bacterial or viral contamination. Field observations and laboratory experiments have shown that most of the toxins produced by Dinophysis are released into the medium, raising questions about the ecological role of extracelular toxins and their potential uptake by shellfish. Shellfish contamination results from a complex balance between food selection, adsorption, species-specific enzymatic transformations, and allometric processes. Highest risk areas are those combining Dinophysis strains with high cell content of okadaates, aquaculture with predominance of mytilids (good accumulators of toxins), and consumers who frequently include mussels in their diet. Regions including pectenotoxins in their regulated phycotoxins will suffer from much longer harvesting bans and from disloyal competition with production areas where these toxins have been deregulated.

Effects of phytoplankton blooms on juvenile salmon in Cowichan Bay in 2014 and 2015.

As part of the Salish Sea Marine Survival Project, a pioneer research was initiated to study the effects of phytoplankton dynamics on wild juvenile salmon. During a 2 year observation period in Cowichan Bay we found strong evidence of phytoplankton blooms having impact on juvenile salmon. During high biomass blooms, Chinook salmon significantly reduced feeding with a two fold increase in the proportion of empty stomachs. Change in the behavior of Chinook salmon and a 25 fold increase in post pit-tagging mortality was also associated with a bloom of Heterosigma akashiwo. High concentrations of mechanically harmful Chaetoceros convolutus and C. concavicorne appeared to cause lesions and necrosis in salmon gills. These observations suggest that algal blooms and/or their absence in coastal waters could have profound impacts on juvenile salmon survival

Comparison of bottom-up processes in Canadian subregions of the Salish Sea

The Salish Sea is a complex coastal region wherein annual variations in prey availability for salmon have changed over time. Specific areas within this region have distinct physical oceanographic features and thus may play an important role in seasonal and interannual variability of lower trophic levels. As part of the Salish Sea Marine Survival Project we are investigating how bottom-up processes differ between regions within the Canadian areas of the Salish Sea, in part to determine if variations in prey availability in these subregions affect the health and/or foraging success of young herring and salmon. Environmental drivers (SST, PAR, wind), oceanographic conditions (from CTD data), in addition to phytoplankton and zooplankton community composition will be compared across the different subregions. Hotspot analyses on mean monthly phytoplankton and zooplankton biomass will provide information as to which areas are more productive. In addition, a simultaneous data-driven approach based on taxonomic composition will indicate how well our defined subregions represent natural spatial distributions of phytoplankton and zooplankton communities. Preliminary results of satellite-derived chlorophyll a from 2015 show that the Juan de Fuca and Tidal Mixed regions had consistently lower phytoplankton biomass throughout all seasons. Analysis of in situ phytoplankton samples revealed similar results with relatively low cell densities occurring in the Tidal Mixed region throughout the year. In contrast, the Central region had the highest phytoplankton biomass in the spring, whereas the highest biomass in the summer was observed in the Northern region. Variations were also observed in monthly anomalies of zooplankton biomass, with the highest positive anomalies occurring in Baynes Sound. Results from this work will ultimately be combined with juvenile salmon studies to address whether variations in prey availability within these different subregions affect the health and survival of juvenile salmon in the northern Salish Sea