The role of Sarcocornia perennis and tidal flooding on sediment biogeochemistry in a South American wetland

NEGRIN, V.L.; SPETTER C.V.; GUINDER V. A.; PERILLO G. M. E.; MARCOVECCHIO J. E.

MARINE BIOLOGY RESEARCH

TAYLOR & FRANCIS AS

Lugar: Londres; Año: 2013 vol. 9 p. 703 - 715

1745-1000

The  roles  of  Sarcocornia  perennis  and  tidal  flooding  on  sediment  biogeochemistry  were evaluated  within  a  wetland  in  the  Bahía  Blanca  estuary.  pH  and  Eh  were  measured  in sediments  while  particulate  organic  carbon  (POC)  and  dissolved  inorganic  nutrients concentrations were determined in porewater, in three sites with different conditions according to both factors (vegetation and flooding). Grain size was also analyzed. pH varied in a narrow range (7-8.2) and was  lower  in  the vegetated site. Eh values 50-250 mV imply that the sediment conditions were moderately reduced, in agreement with the relative high percentage of sand;  it was  influenced by both  factors. POC concentration was high  (26.24  ±  1.62 mg/L),  especially  in  the  vegetated  site.  The  concentrations   ammonium  and  nitrate  were  similar  (21.30  ±  1.83  µmol/L  and  18.77  ±  3.06  µmol/ respectively),  and  not  affected  by  flooding;   only  nitrate    was  affected  by vegetation. Phosphate was rather constant (13.43 ± 1.19 µmol/L) and affected mainly by flooding. Silicate was high (566.45 ± 76.06 µmol/L) and not affected by neither factor.  These  results  suggest  that  the  sediment  biogeochemistry  of  the environment  is  significantly  influenced  by flooding  and,  especially,  S.  perennis, as vegetation  affected  a  higher  number  of  parameters.