Dauby, Patrick

Gobert, Sylvie

Lepoint, Gilles

Mascart, Thibaud

Remy, François

English

Ghent University Academic Bibliography

Has oxygen depletion an impact on nutrients and macrofauna in a highly dynamic macrophytodetritus accumulation?   Remy F1, Mascart T12, Dauby P3,Gobert S1, Lepoint G1   1 MARE Centre, Laboratory of Oceanology, University of Liège, B6c, 4000 Liège, Belgium  2 Marine Biology, Gent University 281 S8, 9000 Gent, Belgium  3 MARE Centre, Laboratory of Sytematics and Animal Diversity, University of Liège, B6c, 4000 Liège, Belgium  Contact: francois.remy@ulg.ac.be    General framework Methods Results A) Through years 2010-2012  B) For the 4 dominant species Take home message Fig 1 : A = P.oceanica litter accumulation; B = litter monsters ;  C = the macro-invertebrates.  Fig 2 : A&B : seasonal and spatial evolution of (A) O2 concentration/saturation and nutrients (B) for years 2010-2012 at 1 of the 2 sites in the water column, in the water just above the litter and in the water inside the litter (plus sediment water for nutrients).      = O2 « debt ».  In a few words :  • Significant differences for nutrients,O2 % saturation and O2 concentration, between sites, seasons and years only for litter water and sediment water (for nutrients only). • Highly significant (p<0,0001) positive (NOx) and negative (NH4, PO4) correlation between nutrients and O2 concentration. Fig 3 : correlation between O2 concentration (mg O2/L) inside the litter and the abundance of 4 important macro-invertebrates species : Melita hergensis, Nebalia strausi, Gammarella fucicola and Gammarus aequicauda. r= Spearman  correlation; p = p value of Spearman correlation test. Solid black line : fitted correlation , dotted red curves : 95% positive and negative confidence bands. • No significant correlation for global macrofauna abundance (≈ 130 species) or global biodiversity (not shown). • No significant correlation for 2 dominant amphipod species :G. fucicola,       G. aequicauda. • Positive significant correlation between mg O2/L and the abundance of the amphipod, M. hergensis. • Negative significant correlation between mg O2/L and the abundance of the leptostracan, N. strausi. • Litter water  important spatio-temporal variations of O2 conditions.  • Effects of low O2 conditions  not visible at a global macrofauna community scale. • Abundance of some dominant species not correlated with O2 concentration, but some show significant positive or negative correlations  responses/tolerances species dependant + adaptation.  • Positive or negative « responses » of nutrients to low O2 conditions  litter = transitional layer between water column and sediment?   Structuring role of O2 dynamics on the litter macrofauna community    * • Revellata Bay, Calvi, CORSICA. • 2 sampling sites (exported accumulations), 2 years, 8 seasons, 3(-4) water strata. • Standardized sampling. • Here: focus on 4 very dominant macro-invertebrates. • Winkler titration for O2, SKALAR spectrophotometry for nutrients. • Posidonia oceanica seagrass  phytodetritus (300 to 2000 g.dry.wt.m-2yr-1), called “litter” (“QR code”1).  • Habitat for macrofaunal community (≈ 130 species). • Highly dynamic (“QR code” 2). • Transient low O2 conditions.  Positive or negative effect? The authors warmly thank the STARESO field station staff for their support during the sampling campaign. Renzo Biondo for his precious help for the oxygen and nutrient measurements. The first author acknowledges a PhD F.R.I.A. grant (Fund for Research Training in industry and in agriculture) of the Belgian National Fund for Scientific Research (FRS-FNRS). This study was conducted within the frame of FRS-FNRS research project FRFC 2.4511.09 (University of Liège). Acknowledgements Poster presented in Liège for the 46th GHER Liège International Colloquium, 5th-9th May 2014, Liège * A B A C * * * 1 2 B PhD Student Poster Contest Hypoxia (30%) 

Has oxygen depletion an impact on nutrients and macrofauna in a highly dynamic macrophytodetritus accumulation?

https://biblio.ugent.be/publication/6843638/file/6843656

Has oxygen depletion an impact on nutrients and macrofauna in a highly dynamic macrophytodetritus accumulation?

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