220 likes | 357 Views
Fisheries and Oceans Canada. Pêches et Océans Canada. Canada. Ecosystem Variability in NAFO Waters Adjacent to the Newfoundland and Labrador Shelf during the Decade of 2000-2009. By E. Colbourne, P. Pepin and G. Maillet Fisheries and Oceans Canada. OUTLINE. Introduction
E N D
Fisheries and Oceans Canada Pêches et Océans Canada Canada Ecosystem Variability in NAFO Waters Adjacent to the Newfoundland and Labrador Shelf during the Decade of 2000-2009 By E. Colbourne, P. Pepin and G. Maillet Fisheries and Oceans Canada
OUTLINE • Introduction • Decadal Scale Variability in Meteorological and Oceanographic Climate (1950-2009) • Intra-Decadal Variability in the Physical, Biological and Chemical Environment (2000-2009) • Summary
The Study Area/ Observations • ICNAF 1949-1979 • NAFO 1979-Present • Focused on Physical Observations • Canadian Atlantic Zone Monitoring Program (AZMP) • 1999-Present
Groundfish surveys - Selected stations Atlantic Zone Monitoring Program (AZMP)- a joint initiative of 5 DFO labs- Physical, Biological and Chemical Observations Sections – Spring Summer and fall Fixed stations – Every two weeks Remote Sensing - Bi-weekly composites Continuous Plankton Recorder (CPR)
OUTLINE • Introduction • Decadal Scale Variability in Meteorological and Oceanographic Climate (1950-2009) • Intra-Decadal Variability in the Physical, Biological and Chemical Environment (2000-2009) • Summary
NWA AIR TEMPERATURES NAO AIR TEMP • Highest on record during 2000s • Highest variability during the 1970-1990s SST
NL SHELF SEA ICE EXTENT Sea-Ice Lowest Since 1960s • Sea-Ice Lowest Since 1960s • Highly variable during 1970-1990s
NL SHELF TEMPERATURES STATION 27 • Record High Temp in 2000s • Salinity Record Low in 1990s Record High in 2000s
STANDARD SECTIONS CIL Low Variability in 2000s, 1950S
LABRADOR CURRENT GEOSTROPHIC TRANSPORT • Geostrophic Transport of Labrador Current above average in 2000s.
1970s 1980s 1990s 1960s 2000s 1950s COMPOSITE CLIMATE INDEX • Standardized Anomalies of 27 Meteorological, Sea Ice, Temperature, Salinity Time Series (Xi-Xmean)/σ (1971-2000)
COMPOSITE CLIMATE INDEX SALINITY
RECAP DECADAL TRENDS • The 1970s, 1980s and 1990s experienced extreme intra-decadal variability with cold/warm, fresh/saline conditions. • The 1990s experienced the most extreme variability and was the coldest and freshest in the 6 decades of observations. • The decade of 2000s was the warmest decade in over 60 years of ocean measurements but very similar to 1960s. • The 2000s showed among the least variability reflecting a continuing warming trend throughout the region.
OUTLINE • Introduction • Decadal Scale Variability in Meteorological and Oceanographic Climate (1950-2009) • Intra-Decadal Variability in the Physical, Biological and Chemical Environment (2000-2009) • Summary
STATION 27 – Zooplankton Biomass • Biomass highly variable, record low in 2008 to near-record high in 2009. • High levels of abundance of large and small copepods in 2009Microcalanus sp., Oithona sp., Pseudocalanus sp. and Oncaea sp. • Warm water species Acartia sp., Centropages sp., and Temora longicornis were at low levels of abundance.
Standard Sections (NL) Zooplankton Abundance • Both small and large copepods demonstrated similar patterns of variation. • Lowest abundances at the start of the time-series, with a gradual increase to a peak between 2004-2006. • After 2006, copepods were about average for the AZMP period. • Other groups carnivores, omnivores and non-copepod secondary producers (meroplankton) exhibited similar patterns.
SALINITY Environmental Forcing and Biogeochemical State • During the 12 years of AZMP observations, the physical environment was characterized by warm saline conditions. • Low intra-decadal variability, reflecting the warming trend throughout the region.
PHYTOPLANKTON NITRATE (0-50 M) Environmental Forcing and Biogeochemical State Standard Sections Station 27 • Most correlations were weak and not consistent across the region. • Phytoplankton at S27 demonstrated consistent negative correlations with most climate indices. • In general, nutrient and phytoplankton had a significantly greater proportion of negative correlations than expected by chance (85/130). Correlation coefficients of environmental variables with biochemical indices
Environmental Forcing and Biogeochemical State 27 Zooplankton Taxa (Standard Sections) • No single environmental variable demonstrated a consistent pattern of correlations with the 27 zooplankton taxa. • And no single zooplankton taxa demonstrated a consistent pattern of correlation with any environmental index. • 59% of the 3080 correlations were positive, which is a significant departure from random. Box-whisker plots of the distribution of Pearson’s correlation coefficient of each index of physical environmental variables (y-axis) with all indices of zooplankton abundance (27 taxonomic groups) from each of the four oceanographic sections.
NUTRIENTS PHYTOPLANKTON ZOOPLANKTON AZMP BIOGEOCHEMICAL COMPOSITE (2000-2009) (Xi-Xmean)/σ (Referenced 1999-2010)
Environmental Forcing and Biogeochemical State • The decade of 2000s was characterized by warm climate conditions. • The biochemical state exhibited a high degree of inter-annual variability during this period.
BIOCHEMICAL SUMMARY 2000s • Nutrient were weakly correlated (-ive) with the physical environment. • Phytoplankton at Station 27 was significantly correlated (-ive) with the physical environment. • Some zooplankton taxa varied by 2-orders of magnitude with a general tendency towards +ive correlations with the physical environment. • No single environmental index provides strong predictive capacity of the biochemical state. • Environmental conditions have not varied sufficiently during AZMP to allow an accurate assessment of the full response of ecosystem productivity to changes in physical drivers of the system.