Tolerance of the Baltic amphipodMonoporeia affinisto hypoxia, anoxia and hydrogen sulfide

Abstract

Abstract Tolerance of different levels of hypoxia and hydrogen sulfide was tested for the amphipod Monoporeia affinis. M. affinis was exposed to 6.7 kPa and <0.2 kPa oxygen tension and 25μM and 50μM sulfide. The tolerance of M. affinis to moderate hypoxia (6.7 kPa oxygen) was relatively good as only 3.3 ± 1.7% of the animals were dead after 120h of exposure. In severe hypoxia (<0.2 kPa oxygen) the LT50 value was 91 ± 25.7h which is higher than previously found for M. affinis. Survival of M. affinis significantly decreased when sulfide was added. An LT50 of 14.2 ± 1.3h for 25μM sulfide exposure with 1.1 kPa oxygen did not change (LT50= 13.5 ± 2.0h) significantly when no oxygen was available. Consequently, M. affinis can be classified as a species that is not tolerant of sulfide, and being one of the primary food sources for fish and invertebrates in the northern Baltic Sea its low tolerance gives further evidence on the detrimental effects of severe oxygen deficiency and hydrogen sulfide.