This entry provides access to the figures and data tables that feature in the CSAS Research Document titled 'Optical, chemical, and biological oceanographic conditions on the Scotian Shelf and in the eastern Gulf of Maine in 2013'. Please consult the meta-data text file that accompanies the zip file download for the figure on the data usage policy and appropriate citation. The meta-data file also provides field descriptors and any other information that may be useful in interpreting the data provided in relation to the accompanying imagery. Abstract: Ocean conditions were unusually warm and stratified on the Scotian Shelf in 2012, and the plankton response to the physical environment in 2012 set the initial conditions for the plankton in 2013. In particular, zooplankton biomass and the abundance of the two dominant herbivorous copepod species, Calanus finmarchicus and Pseudocalanus spp., were low, and there appeared to be a shift to a smaller-size phytoplankton community on the Scotian Shelf. In 2013, annual average temperature anomalies were still positive in the Maritimes Region, but less so than in 2012, and temperature and stratification anomalies were marked by strong sub-annual and mesoscale variability. Variability in the physical environment was reflected in nutrient and plankton conditions. Annual average deep-water and winter surface nitrate inventories were similar to average overall, but surface nitrate was higher than average. The magnitude of the spring bloom chlorophyll peak was above average on the Eastern Scotian Shelf (ESS) and below average on the Western Scotian Shelf (WSS) and in the eastern Gulf of Maine, but summer-fall blooms were above average in all areas. Zooplankton biomass and abundance were lower than average on the eastern transects, but anomalies were mixed on the Central Scotian Shelf, ESS and Bay of Fundy. The abundance of Pseudocalanus spp. was higher than average in the central and western part of the region. Although C. finmarchicus abundance was variable and lower than average overall, it was high on the WSS and in the eastern Gulf of Maine during the summer ecosystem trawl survey and higher than average at the Halifax-2 station and in Emerald Basin in autumn, suggesting a return to more typical abundances in the western part of the region at the end of 2013. Similar to the broader Scotian Shelf, the 2013 Bedford Basin annual average temperature was warmer than normal but not as warm as 2012. Small phytoplankton were more abundant than average in Bedford Basin and large phytoplankton less abundant. An initial evaluation of relationships among annual anomalies of physical variables, nitrate, spring bloom metrics and zooplankton at Halifax-2 from 1999 to 2013 identified bloom duration and enhanced upwelling as important correlates of zooplankton biomass and dominant copepod abundance at an annual scale. Continuous Plankton Recorder sampling showed that observations of phytoplankton bloom dynamics and abundance of C. finmarchicus at Halifax-2 in 2012 were representative of shelf-wide patterns. http://www.dfo-mpo.gc.ca/csas-sccs/Publications/ResDocs-DocRech/2014/2014_104-eng.html

This entry provides access to the figures and data tables that feature in the CSAS Research Document titled 'Optical, chemical, and biological oceanographic conditions on the Scotian Shelf and in the eastern Gulf of Maine in 2012'. Please consult the meta-data text file that accompanies the zip file download for the figure on the data usage policy and appropriate citation. The meta-data file also provides field descriptors and any other information that may be useful in interpreting the data provided in relation to the accompanying imagery. Abstract: In 2012, anomalously warm ocean temperatures throughout the water column on the Scotian Shelf and eastern Gulf of Maine influenced the chemical and biological conditions of the region. Stratification was higher than average on the Scotian Shelf. At the Halifax-2 fixed station, upper water column (0-50 m) nitrate was lower than normal throughout 2012, while deep water (50-150 m) nitrate concentrations were much higher than normal, suggesting that stratification may have inhibited nutrient mixing into the upper water column. Deep water nitrate concentrations were also higher than average throughout most of the region. Spring bloom initiation timing at Halifax-2 was about average, and the bloom was average in magnitude but short in duration, but winter chlorophyll concentrations were higher than average. Satellite ocean color observations also indicated high winter chlorophyll concentrations and early and/or short spring bloom timing across much of the Scotian Shelf. Although chlorophyll concentrations were about average following the spring bloom at Halifax-2, light attenuation was high, cell abundances were low, and diatoms and dinoflagellates were less relatively abundant and flagellates and ciliates more relatively abundant than normal, suggesting a shift to a smaller-sized phytoplankton community, possibly including higher than average concentrations of picoplankton. At the Prince-5 fixed station, the seasonal chlorophyll cycle was similar to normal, but chlorophyll values were higher than average in July and August, when chain forming diatoms (July) and dinoflagellates (August) were abundant. Satellite ocean colour indicated higher than average surface chlorophyll across the eastern Gulf of Maine in August and September. Zooplankton biomass was very low at Halifax-2 throughout 2012, and it was also low on all shelf sections in fall. At Prince-5, zooplankton biomass was mostly low in the first half of the year but rebounded in the fall. At both fixed stations,Calanus finmarchicus abundances were low everywhere throughout 2012. C. finmarchicus production was likely impacted by its low abundance at the end of 2011 and high temperatures experienced by the dormant stock during the fall and winter of 2011/2012. At Halifax-2, a short phytoplankton bloom and low diatom abundance may have also contributed to low abundances of C. finmarchicus and Pseudocalanus spp. during 2012. Transient high abundances of small-particle-feeding zooplankton taxa (appendicularians, salps, pteropods) were observed both on the Scotian Shelf and at Prince-5. Cold-associated immigrant species (Arctic Calanus) were less abundant and warm offshore species generally more abundant than average in 2012, consistent with warmer temperatures and model estimates of changes in circulation. Overall, lower trophic level changes in 2012 suggest poor feeding conditions for planktivores on the Scotian Shelf, but the late summer-early fall bloom in the eastern Gulf of Maine and Bay of Fundy may have been favorable for some higher trophic level species. http://www.dfo-mpo.gc.ca/csas-sccs/Publications/ResDocs-DocRech/2013/2013_070-eng.html

This entry provides access to the figures and data tables that feature in the CSAS Research Document titled 'Optical, chemical, and biological oceanographic conditions on the Scotian Shelf and in the eastern Gulf of Maine in 2015'. Please consult the meta-data text file that accompanies the zip file download for the figure on the data usage policy and appropriate citation. The meta-data file also provides field descriptors and any other information that may be useful in interpreting the data provided in relation to the accompanying imagery. Abstract: As warm and variable ocean conditions persisted in the Maritimes Region in 2015, there was increasing evidence of a shift in both phytoplankton and zooplankton communities away from the dominance of large phytoplankton and copepods toward smaller phytoplankton and copepod species. Although deep-water nitrate inventories were mainly higher than average in 2015, deep silicate and phosphate inventories were lower than average on the Scotian Shelf for the third year in a row. The spring bloom started later than normal and was weaker in magnitude and shorter in duration than usual. Phytoplankton biomass anomalies were mixed across the Shelf, but the abundance of large phytoplankton, particularly diatoms, was lower than average, continuing a pattern started in 2009. The abundance of the biomass-dominant copepod species Calanus finmarchicus and zooplankton biomass overall were lower than average overall in 2015, as was the abundance of Arctic Calanus species, continuing a pattern started during the last 4-7 years. In contrast, the abundances of offshore copepods were higher than average. Changes in phytoplankton and zooplankton communities observed in recent years indicate poor feeding conditions for planktivorous fish, birds, and mammals. Continuous Plankton Recorder sampling, the reporting of which lags Atlantic Zone Monitoring Program sampling by one year, indicated that in 2014 the spring phytoplankton bloom occurred earlier and was of shorter duration than normal over the entire Scotian Shelf and that the springtime peaks in abundance of the dominant zooplankton taxa Calanus I-IV and C. finmarchicus V-VI were also relatively early and relatively short-lived. 2014 annual abundance anomalies were unusually high for hyperiid amphipods and foraminifera over the entire Scotian Shelf in 2014, and unusually low for euphausiids. Annual abundance anomalies for most other taxa were at near normal levels on the western Scotian Shelf and below normal levels on the eastern Scotian Shelf. http://www.dfo-mpo.gc.ca/csas-sccs/Publications/ResDocs-DocRech/2017/2017_012-eng.html