Geochemical Changes in Aquatic Environment Caused by Deep Dredging - A Case Study: The Puck Bay (Baltic Sea)

摘要: Dredge activities is very widespread antropogenic seabed disturbance. It used to replenish sand on beaches, create and maintain harbor, berth, waterways, may also be for underwater mining as a technique fishing certain species of crabs or edible clams. Dredging has many deleterious environmental effects (Johnston 1981). Changes in bottom topography due dredging can influence water dynamic consequence sediment transport (Maa et al., 2004; Work at al. 2004). pits deep furrows sink fine-grained sediments, organic matter contaminants (Desprez 2000) result hypoxic anoxic conditions, well sulfate reduction (Bolalek 1996, Flocks&Franze 2002, Graca 2004) (Fig. 1). Geochemical changes resulted affect benthic organisms. Limited recolonization dredge was observed (Palmer 2008, Szymelfenig 2006). Such condition nutrients potentially stimulate eutrophication (Graca Impact depends its intensity the type method, area (Boyd 2005, Robinson 2005). Puck Bay small body located Polish Baltic coast. Deep works carried this reservoir, creates great opportunity study impact areas with different dynamics. From north bay restricted from open by Hel Peninsula. 34 km long, width varies 0.2 2.9 km. A change peninsula land cover during last few decades, especially construction new enhanced erosion processes. At present, Peninsula requires intensive reinforcement (Urbanski & Solanowska, 2009). Eighty-two percent (c.a. 6,98 mln m3) sands peninsula’s bank protection gained Bay. First large beach nourishment out end 80’s century. As an effect, years 1989-95, five were created along (Fig.2). The depth reaches 7-14 m, while natural surrounding does not exceed 2 m.