Long term mesozooplankton changes in coastal waters of North Spain Ricardo González-Gil F....
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Transcript of Long term mesozooplankton changes in coastal waters of North Spain Ricardo González-Gil F....
Long term mesozooplankton changes in coastal waters of North
Spain
Ricardo González-GilF. González-Taboada, J. Höfer, R. Anadón
University of Oviedo Department of Biology of Organisms and Systems
In colaboration with
Instituto Español de Oceanografía
Ricardo González-Gil
Long-term monitoring program RADIALES by the Spanish Institute of Oceanography (Instituto Español de Oceanografía, IEO) in collaboration with the UO
Cantabrian Sea Offshore of Cudillero (Asturias)
Monthly sampling January 1993 to December 2010
The study area
Coastal Station
Shelf-break Station
Oceanic Station
Ricardo González-Gil
Analysis of mesozooplankton changes1. Long-term trends
2. Other underlying aspects of these long-term trends:
1. Modifications in seasonality2. Effects from changes in the
interannual environmental conditions: variations of the Central Water mass regime
Ricardo González-Gil
The study variablesBiological variables:
Mesozooplankton variables
Biomass Fractionated biomass (200-500 μm, 500-1000 μm, > 1000 μm) Abundance
Phytoplankton variables
Integrated Chl a, from 50 m to the surface
Physical variables:
Temperature Salinity on the isopycnal 27. 1 Marker for Central Water mass types
Ricardo González-Gil
Long-term trendsZooplankton time series context in the North Atlantic Ocean
Data from Global comparisons of zooplankton time series (SCOR WG 123). Time series also associated with the ICES-WGZE(ICES Working Group on Zooplankton Ecology) http://wg125.net/
Criteria
• Current data: Data at least until 2008
• Sampling frequency: every month
Ricardo González-Gil
Long-term trends
Dummy variable seasonal regression
tt NovcFebcJancbtaY 1121 ...
Time
Long-term trend component
Time
Seasonal component
Time
Random or noise component
Ricardo González-Gil
***
******
*
Long-term trends (1993-2010)
P-value
*** <0. 001
** <0.01
* <0. 05
<0. 1
• Positive trends for all the variables.
• Only highly
significant for Zoo BM.
Chl a Zoo BM Zoo abundance
Ricardo González-Gil
P-value
*** <0. 001
** <0.01
* <0. 05
<0. 1
*
*****
***
***
***
***
**
Long-term trends (1998-2010). Fractionated biomass• Positive trends
• Unexpected compared to other works: More intense, significant and explanatory trends at larger fractions
200-500 µm 500- 1000 µm > 1000 µm
Ricardo González-Gil
Long-term trends (1993-2010) Temperature
• Warming trends: higher and more significant for the more oceanic station (more stable conditions)
• Decreasing significance towards deeper waters
Atm.Effect
Ricardo González-Gil
Changes in seasonality
10 m depth Temperature
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Changes in seasonalityChl a
Earlier spring bloom/more intense spring and autumn bloom
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Changes in seasonalityZooplankton biomass
more intense spring and autumn peak
Ricardo González-Gil
ENACWsp(subpolar
gyre)
BBCW(Celtic sea)
ENACWst(Subtropical
gyre)
IPC
Modified from Pérez et al. 2001
• BBCWBay of Biscay Central Water
• ENACWspEast North Atlantic Central Water subpolar mode
• ENACWstEast North Atlantic Central Water subtropical mode
• IPCIberian Poleward Current/Navidad
Variations of Central Water masses
Ricardo González-Gil
Variations of Central Water masses• Identification: T-
S profiles
• Marked periods:
• For BBCW• For ENACWst
Ricardo González-Gil
Variations of Central Water masses
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Variations of Central Water massesInfluence on biological variables
ANOVA: No significant differences
Ricardo González-Gil
ANOVA and Tukey tests results:
Significant differences for E2 (shelf-break station)
• Highly significant differences between ENACWst and ENACWsp
• Significant differnces between ENACWst and BBCW
Zoo abundance
Ricardo González-Gil
Conclusions• For the long term trends:
• Detection of significant positive trend for Zooplankton biomass.
• Positive long term trends for all the biomass fractions. Unexpected more intense and markedly positive long term trends for larger zooplankton fraction sizes.
• For Changes in seasonality:
• For Chl a: Earlier spring bloom/more intense spring and autumn bloom.
• For zooplankton biomass: more intense spring and autumn peak.
• For variations of the Central Water mass regime
• Effect on the zooplankton abundance for the shelf-break station.
ACKNOWLEDGEMENTS
This work was supported by a grant from the Ministerio de Educación del gobierno de España (FPU grant) and by the Instituto Espanñol de Oceanografía (Project Radiales)
Thanks to:
The crew of the research vessel José Rioja ;
The people from the ecology area of the University of Oviedo for advice and guidance;
Thank you also for all the support and advice from loved ones.
Ricardo González-Gil
P-value for long term trend(Seasonal regression): 1993-2010 P-value for long term trend(Seasonal regression): 1998-2010
Station log10_Chla log10_Bm_ zooplank log10_abund _zooplank log10_Bm_200_
zooplanklog10_Bm_
500_zooplanklog10_Bm_
1000_zooplank
E1 0.01060925 0.00000484 0.02725876 0.02490764 0.00064670 0.00009204
E2 0.06127331 0.00055801 0.25373958 0.17635892 0.00017461 0.00000058
E3 0.08910399 0.00487024 0.05275587 0.00528685 0.00003303 0.00112041
Ricardo González-Gil
BB
CW
Ricardo González-Gil
EN
AC
Wst