scholarly journals Immediate and delayed effects of a mass mortality event on gorgonian population dynamics and benthic community structure in the NW Mediterranean Sea

2005 ◽  
Vol 305 ◽  
pp. 127-137 ◽  
Author(s):  
C Linares ◽  
R Coma ◽  
D Diaz ◽  
M Zabala ◽  
B Hereu ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Community Structure ◽  
Mediterranean Sea ◽  
Benthic Community ◽  
Mass Mortality ◽  
Benthic Community Structure ◽  
Delayed Effects ◽  
Mass Mortality Event ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

scholarly journals Short scale variations in nutrients, ectoenzymatic activities and bottom-up effects on bacterial production and community structure during late summer-autumn transition in the open NW Mediterranean Sea

2009 ◽  
Vol 6 (1) ◽  
pp. 687-727 ◽  
Author(s):  
F. Van Wambeke ◽  
J-F. Ghiglione ◽  
J. Nedoma ◽  
G. Mével ◽  
P. Raimbault
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Mediterranean Sea ◽  
Mixed Layer ◽  
Bacterial Production ◽  
Bacterial Community Structure ◽  
Late Summer ◽  
Bottom Up ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

Abstract. We examined the vertical and temporal dynamics of nutrients, ectoenzymatic activities under late summer-fall transition period (September–October 2004) in NW Mediterranean Sea in relation to temporal change in factors limiting bacterial production. The depth of the mixed layer (12.8±5.3 m) was extremely stable until the onset of the destratification period after 11 October, creating a zone where diffusion of nutrient from the much deeper phosphacline (69±12 m) and nitracline (50±8 m) was probably strongly limited. However during the second half of the cruise, a shallowing of nutriclines occured, particularly marked for nitracline. Hence, the nitrate to phosphate ratio within the mixed layer, although submitted to a high short term variability, shifted the last week of the cruise from 1.1±1.2 to 4.6±3.8, and nitrate increased by a factor 2 (0.092±0.049 μM). A corresponding switch from more than one limitation (PN) to P-only limitation of bacterial production was observed during the month as detected by enrichment bioassays. Differences in the identity of the limiting nutrient in surface (5 m: N and P at the beginning, strictly P at the end of the study) versus 80 m (labile carbon) influence greatly bacterial community structure shift between these two layers. The two communities (5 and 80 m) reacted rapidly (24 h) to changes in nutrient concentrations by drastic modification of total and active population assemblages resulting in changes in activity. For bacterial production values less than 10 ng C l−1h−1 (associated to deeper layers), aminopeptidase and lipase exhibited higher activity relative to production whereas phosphatase varied in the same proportions than BP on the range of activities tested. Our results illustrate the effect of bottom-up control on bacterial community structure and activities in the epipelagic NW Mediterranean Sea.

Impact of lower salinity waters on bacterial heterotrophic production and community structure in the offshore NW Mediterranean Sea

2010 ◽  
Vol 2 (6) ◽  
pp. 761-769 ◽  
Author(s):  
Mélissa Laghdass ◽  
Nyree J. West ◽  
Nicole Batailler ◽  
Jocelyne Caparros ◽  
Philippe Catala ◽  
...  
Keyword(s):  
Community Structure ◽  
Mediterranean Sea ◽  
Lower Salinity ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea ◽  
Heterotrophic Production

scholarly journals Bottom up effects on bacterioplankton growth and composition during summer-autumn transition in the open NW Mediterranean Sea

2009 ◽  
Vol 6 (4) ◽  
pp. 705-720 ◽  
Author(s):  
F. Van Wambeke ◽  
J.-F. Ghiglione ◽  
J. Nedoma ◽  
G. Mével ◽  
P. Raimbault
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Mediterranean Sea ◽  
Mixed Layer ◽  
Bacterial Production ◽  
Bacterial Community Structure ◽  
Bottom Up ◽  
Production Values ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea

Abstract. We examined the vertical and temporal dynamics of nutrients, ectoenzymatic activities under late summer-fall transition period (September–October 2004) in NW Mediterranean Sea in relation to temporal change in factors limiting bacterial production. The depth of the mixed layer (12.8±5.3 m) was extremely stable until the onset of the destratification period after 11 October, creating a zone where diffusion of nutrient from the much deeper phosphacline (69±12 m) and nitracline (50±8 m) was probably strongly limited. However after 1st October, a shallowing of nutriclines occured, particularly marked for nitracline. Hence, the nitrate to phosphate ratio within the mixed layer, although submitted to a high short term variability, shifted the last week of the cruise from 1.1±1.2 to 4.6±3.8, and nitrate increased by a factor 2 (0.092±0.049 μM). A corresponding switch from more than one limitation (PN) to P-only limitation of bacterial production was observed during the month as detected by enrichment bioassays. Differences in the identity of the limiting nutrient in surface (5 m: N and P at the beginning, strictly P at the end of the study) versus 80 m (labile carbon) influence greatly bacterial community structure shift between these two layers. The two communities (5 and 80 m) reacted rapidly (24 h) to changes in nutrient concentrations by drastic modification of total and active population assemblages resulting in changes in activity. For bacterial production values less than 10 ng C l−1 h−1 (associated to deeper layers), aminopeptidase and lipase exhibited higher activity relative to production whereas phosphatase varied in the same proportions than BP on the range of activities tested. Our results illustrate the effect of bottom-up control on bacterial community structure and activities in the epipelagic NW Mediterranean Sea.

scholarly journals Role of environmental factors for the vertical distribution (0–1000 m) of marine bacterial communities in the NW Mediterranean Sea

2008 ◽  
Vol 5 (6) ◽  
pp. 1751-1764 ◽  
Author(s):  
J. F. Ghiglione ◽  
C. Palacios ◽  
J. C. Marty ◽  
G. Mével ◽  
C. Labrune ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Mediterranean Sea ◽  
Water Column ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Sampling Period ◽  
Nw Mediterranean ◽  
Nw Mediterranean Sea ◽  
Bacterial Assemblages

Abstract. Bacterioplankton plays a central role in energy and matter fluxes in the sea, yet the factors that constrain its variation in marine systems are still poorly understood. Here we use the explanatory power of direct multivariate gradient analysis to evaluate the driving forces exerted by environmental parameters on bacterial community distribution in the water column. We gathered and analysed data from a one month sampling period from the surface to 1000 m depth at the JGOFS-DYFAMED station (NW Mediterranean Sea). This station is characterized by very poor horizontal advection currents which makes it an ideal model to test hypotheses on the causes of vertical stratification of bacterial communities. Capillary electrophoresis single strand conformation polymorphism (CE-SSCP) fingerprinting profiles analyzed using multivariate statistical methods demonstrated a vertical zonation of bacterial assemblages in three layers, above, in or just below the chlorophyll maximum and deeper, that remained stable during the entire sampling period. Through the use of direct gradient multivariate ordination analyses we demonstrate that a complex array of biogeochemical parameters is the driving force behind bacterial community structure shifts in the water column. Physico-chemical parameters such as phosphate, nitrate, salinity and to a lesser extent temperature, oxygen, dissolved organic carbon and photosynthetically active radiation acted in synergy to explain bacterial assemblages changes with depth. Analysis of lipid biomarkers of organic matter sources and fates suggested that bacterial community structure in the surface layers was in part explained by lipids of chloroplast origin. Further detailed analysis of pigment-based phytoplankton diversity gave evidence of a compartmentalized influence of several phytoplankton groups on bacterial community structure in the first 150 m depth.

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