Spatial variability in water column and sediment chemistry in Heraklion harbour (Crete, E. Mediterranean)

Heraklion harbour, situated in the oligotrophic Eastern Mediterranean Sea, has been contaminated with untreated sewage during the last 25 years. Due t o recent developments these discharges have been ceased in 1998. Sewage dis charge resulted in increased levels of nutrients, chlorophyll a and organic carbon at the inner harbour sites decreasing towards the harbour entrance. Severe impacts were detected in the sediments near the sewage outfalls and the inner harbour stations, where the increased organic material sedimenta tion resulted in sediment anoxia.