Eutrophication is one of the most severe and widespread forms of disturbance affecting coastal marine systems. Whilst there are general models of effects on benthos, such as the PearsonRosenberg (P-R) model, the models are descriptive rather than predictive. Here we first review the process of increased organic matter production and the ensuing sedimentation to the seafloor. It is shown that there is no simple relationship between nutrient inputs and the vertical flux of particulate organic matter (POM). In particular, episodic hydrographic events are thought to be the key factor leading to high rates of sedimentation and accompanying hypoxia. We extend an earlier review of effects of hypoxia to include organisms living in the water column. In general, fishes are more sensitive to hypoxia than crustaceans and echinoderms, which in turn are more sensitive than annelids, whilst molluscs are the least sensitive. Growth is affected at oxygen concentrations between 6.0 and 4.5 mg O 2 l -1

Low dissolved oxygen poses a major threat to coastal marine ecosystems worldwide. This study demonstrates that both growth and reproduction of the amphipod Melita longidactyla are impaired even by moderately low dissolved oxygen levels (3.5 to 4.5 mg O 2 l -1 ), which are higher than levels considered to be hypoxic (2.8 mg O 2 l -1