Experimental recolonisation of Baltic Sea reduced sediments: survival of benthic macrofauna and effects on nutrient cycling

• Published in: Marine ecology. Progress series (Halstenbek) 2005-06, Vol.294, p.35-49
• Main Authors: Karlson, Karin, Hulth, Stefan, Ringdahl, Katja, Rosenberg, Rutger
• Format: Article
• Language: English
• Subjects: AMPHIPOD MONOPOREIA-AFFINIS; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Baltic sea; benthic fluxes; Biological and medical sciences; bioturbation; COASTAL MARINE; denitrification; Ecology; Ekologi; ESTUARINE SEDIMENTS; Fauna; Fundamental and applied biological sciences. Psychology; HYDROGEN-SULFIDE; LAMINATED SEDIMENTS; MACOMA-BALTHICA BIVALVIA; macrofauna; Marine; mineralisation; Nitrates; Nitrification; ORGANIC-MATTER; Oxygen; Phosphates; PONTOPOREIA-AFFINIS; POREWATER PROFILES; Quaternary ammonium compounds; REACTION-RATES; recolonisation; reduced; Sea water; Sea water ecosystems; Seas; SEDIMENT; Sediments; Synecology
• ISSN: 0171-8630; 1616-1599
• DOI: 10.3354/meps294035

A recolonisation experiment was performedin vitroon highly reduced laminated Baltic Sea sediments initially devoid of larger benthic fauna. The survival capacity of 3 common benthic speciesMonoporeia affinis, Macoma balthicaandMarenzelleria viridiswas investigated along with overall effects of bioturbation and bioirrigation on benthic reaction and transport processes. Benthic fluxes of oxygen and nutrients, sediment denitrification and nutrients in the porewater were measured. Survival ofM. affinisincreased with time and sediment reworking, while no such feedback was observed forM. balthicaandM. viridis. Macrofaunal irrigation and bioturbating activities significantly enhanced solute fluxes in the manipulated cores compared to the control. Mass balance calculations indicated that net N-mineralisation in the manipulated cores was stimulated by 1 to 2 orders of magnitude compared to the control. Despite relatively high nitrate fluxes from the overlying water to the sediment (~1 mmol m–2d–1), measured rates of total denitrification were in general low (20 to 45 μmol N₂ m–2d–1) in all cores. Denitrification, using nitrate supplied from the overlying water (Dw), was similar to coupled nitrification/denitrification (Dn), although Dwwas significantly higher than Dnin theM. affiniscores. In conjunction with high nitrate fluxes into the sediment and high ammonium fluxes to the overlying water, the generally low denitrification rates indicated dissimilatory nitrate reduction to ammonium (DNRA) as the main pathway for nitrate removal. Thus, the main source of bottom water ammonium was overlying water nitrate, rather than ammonium produced in surface sediments during mineralisation of organic N.