AZMP Station 27
Newfoundland Shelf
Latitude:   47.5500     Longitude:   -52.5900

 Associated Investigators:
Pierre Pepin  

Related Web Sites:
[www.dfo-mpo.gc.ca]  

Related Time Series:
[ Halifax Line 2 (Scotian Shelf) ]   [ Prince 5 (Bay of Fundy) ]   [ Station 27 (Newfoundland Shelf) ]   [ AR7W Line (Labrador Basin) ]  

Zooplankton are sampled every 2-4 weeks (if possible) from research vessels using a ringnet (0.75 m diameter, 200 µm mesh). Sampling is carried out at a number of stations on a series of transects running perpendicular to the coast of Newfoundland across the Newfoundland and Labrador Shelves and the Grand Banks. The most frequently sampled station, Station 27, is located five nautical miles east of St John s harbour, on the northwestern edge of the Grand Banks and has a 170 m water depth. CTD profiles are recorded, and samples for phytoplankton, nutrients, and extracted Chlorophyll are collected using Niskin bottles at fixed depths. Subsamples are combined to give an integrated sample.

Zooplankton samples are split, and one-half is used for wet-dry weight determination. The other half is subsampled to give at least 200 organisms, which are identified to genus or species and counted. Another subsample is taken containing at least 100 Calanus spp., which are identified to species and stage and counted. Biomasses of the dominant groups are calculated using dry weights of various groupings (Calanus, Oithona, Pseudocalanus, and Metridia) and abundance data.

A more detailed ecosystem status report on the state of chemical and biological oceanographic conditions in the Newfoundland and Labrador region (Canadian Atlantic waters) is prepared every year as a Science Advisory Report.

There is limited seasonal variability in total copepod biomass, but overall, it tends to be higher in autumn than in winter or spring. Interannual variations in total copepod biomass tend to mirror that of large copepods, which dominate the community in weight but not in numbers. Large copepods are most abundant following a spring phytoplankton bloom, reflecting the production cycle of nauplii and copepodites of the dominant Calanus species, whereas the biomass of small copepods peaks in late autumn as a result of large numbers of Oithona spp.. Overall, there are greater interannual variations in the biomass of large copepods relative to smaller species.

The seasonal cycle in local temperatures differs markedly from the Reynolds SST, although the general pattern in interannual variability is similar. The differences reflect the wide area of the continental shelf represented in the Reynolds estimates relative to the more local measurements taken at Station 27, which is located in the inshore arm of the Labrador Current. Similarities in interannual variations are the result of large decorrelation scales for SST anomalies in the region (Ouellet et al., 2003).

Interannual variations in the abundance of large copepods correspond well with the nearest CPR standard area (E9) , but the long-term pattern in variation demonstrates no clear relationship with temperature anomalies in the region. Overall, the abundance of copepods at Station 27 increased in 2007, following 3-4 years with low abundance indices.

REFERENCES:

Ouellet, M., Petrie, B., and Chasse, J. 2003. Temporal and Spatial Scales of Sea-surface Temperature Variability in Canadian Atlantic Waters. Cana-dian Technical Report of Hydrography and Ocean Sciences, 228. 30 pp.