摘要：Marine invasive species may modify their host environment by altering ecosystem biogeochemistry. We hypothesized that the invasive polychaete Marenzelleria viridis in Baltic Sea areas increases sulfate reduction (SR) in sediment micro-zones surrounding its burrow. Consequently, higher free porewater sulfide (H2S) is expected in sediments dominated by M. viridis than in corresponding sediments inhabited by the native polychaete Hediste diversicolor. In a thin-aquaria experiment, we found high SR rates (220 to 539 nmol cm−3 d−1) around the burrow walls of M. viridis as well as in surface and subsurface sediments with overall rates 2-fold higher than in defaunated control sediment. Similarly, an in situ survey revealed subsurface porewater H2S peaks moving upward towards the sediment surface in M. viridis inhabited areas. Accordingly, 50–85% higher porewater H2S was found almost year-round in these areas compared with H. diversicolor inhabited areas, suggesting that the invasion of M. viridis probably led to a substantial change in sediment biogeochemistry. In conclusion, M. viridis stimulates SR in sediment micro-zones and increases H2S in coastal sediments. Such change to more reducing conditions after the invasion may have critical environmental implications on, e.g., the distribution of H2S intolerant flora and fauna species.
