Science Advisory Report  2015/030

Oceanographic conditions in the Atlantic zone in 2014

Summary

• Surface temperatures averaged over all ice-free months were at record highs in the St. Lawrence Estuary and were above normal in all but one region across the zone.
• August surface temperatures were at record highs in 7 of 12 regions in the zone. Surface temperatures in Division 4X‑east and Gulf of Maine‑Bay of Fundy were at record highs for the months of September through December.
• Sea ice volume returned to near normal conditions on the Newfoundland and Labrador (NL) Shelf, highest since 1994, and to the highest average volume in the Gulf of St. Lawrence since 2003. Sea ice was exported to the Scotian Shelf for the first time since 2009.
• Cold Intermediate Layer (CIL) area or volume showed a gradient from larger than normal on the Newfoundland and Labrador Shelf to near normal in the Gulf of St. Lawrence and smaller than normal on the Scotian Shelf. The CIL area on the Grand Banks was the largest since 1985 in spring and since 1997 in July. The July CIL on the Scotian Shelf was the second smallest and was related to transport of warm waters from offshore.
• Bottom temperatures were generally normal or above normal across the zone, including record highs in the deeper waters of the northern Gulf of St. Lawrence and in 4W.
• At high-frequency sampling stations, the 0‑50 m temperatures and stratification were normal to above-normal, and the salinities were near-normal.
• Bottom temperatures were below normal at Station 27, near-normal at the Shediac Valley station where bottom temperatures are influenced by CIL conditions, and above-normal at Halifax 2, Prince 5 and Rimouski station. Temperatures were at a series record high at Rimouski station.
• Seasonal cycles in air and sea surface temperature showed a year of extremes: temperatures were well below average in winter, while well above average values and record highs occurred in summer.
• The Labrador Current transport index was near normal over the Labrador and northeastern Newfoundland Slope and below normal over the Scotian Slope.
• In the Labrador Sea, extreme heat losses in the winter of 2013‑14 led to the most significant volume of newly ventilated Labrador Sea Water since 2007‑08. Winter-time mixed-layer depths in 2013‑14 exceeded 1700 m.
• Two notable freshening events were observed in 2008‑10 and 2011‑14 across the Labrador Sea.
• Deep nitrate inventories on the Newfoundland and Labrador Shelf in 2014 averaged 2.5 SD below normal, continuing the decline that started in 2008. In contrast, deep nitrate inventories in the Gulf of St. Lawrence have increased since 2010, now averaging 0.95 SD above normal. Deep nitrate inventories are near normal on most of the Scotian Shelf.
• Chlorophyll a inventories were near the long-term average throughout much of the Atlantic Zone.
• Since 2004, there has been a trend toward an earlier onset of the spring phytoplankton bloom coupled with lower spring bloom magnitude in the waters off Newfoundland.
• A delayed onset of the spring bloom throughout most of the Atlantic zone in 2014 may have been a reflection of the cold winter in that year. The magnitude of the spring bloom was also below normal throughout most of the zone.
• In 2014, copepod abundance throughout most of the zone has increased relative to levels observed in 2013 but declined to below normal levels in the Labrador Sea and off northern Newfoundland.
• The abundance of Calanus finmarchicus was below to well below normal through much of the Atlantic Zone and the Labrador Sea, with the exception of the Central Scotian Shelf.
• The abundance of Pseudocalanus spp. increased throughout the Gulf of St. Lawrence and most of the Newfoundland Shelf while there has been a decline on the Scotian Shelf and Labrador Shelf.
• Non‑copepod taxa demonstrated a considerable increase in abundance on the Grand Banks and throughout the Gulf of St. Lawrence and Cabot Strait. This appears to be the continuation of a trend that started in 2004.

This Science Advisory Report is from the Seventeenth Annual Meeting of the Atlantic Zone Monitoring Program (AZMP), held March 16-19, 2015. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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