The most widespread human activity contributing to smothering in the Icelandic Waters ecoregion is commercial bottom fishing. In local inshore areas harbour dredging, aggregate extraction of non-living (e.g. sediments) and maerl resources, sediment dumping, cable and pipe laying, and various coastal developments like aquaculture and land reclamation have also caused smothering. In total, 230 046 tonnes of dredged material and 40 138 tonnes of inert material were reported to have been dumped or placed at sea in this ecoregion in 2013.
It is difficult, from lack of data, to evaluate the magnitude of the impact of trawl-induced smothering, but it is likely to have decreased over the last two decades, concomitant with reduced trawl fishing activity.
Coastal habitat loss in the Icelandic Waters ecoregion is caused by various coastal developments, including land reclamation for coastal defences, road building, harbour construction, aggregate extraction, and the construction of bridges across fjords. The level of human activity in coastal areas within the ecoregion is limited and the main coastal developments are related to fisheries. However, there is increased pressure from various activities carried out within coastal areas, particularly to the west of Iceland. On their own, each of these activities may not cause substantial pressure on coastal environments, but when combined they may have localized impacts.
Considering the patchy distribution of settlements in a nation of 330 000 people, these effects are small and localized. Marine aquaculture is a small industry with an annual production of less than 20 000 tonnes, mostly salmon. However, there is a growing interest in aquaculture and a considerable expansion of the activity is planned in fjords along the western and eastern coastlines. The increased traffic of tourists in coastal areas, from sightseeing, whale watching, and sport angling may cause increased localized pressure.
“Other pressures” represents a suite of pressures that are known, or suspected, to affect the Icelandic marine ecosystem.
The carbonate system parameters have been monitored since 1983 at two time-series stations in the Icelandic Waters ecoregion. Data show that the rate of ocean acidification north of Iceland is rapid and surface pH in winter decreases at a rate of 0.0024 yr−1, which is 50% faster than average yearly rates reported from the subtropical Atlantic. In the deep-water regime ( > 1500 m), the rate of pH decline is a quarter of that observed in surface waters. Experimental research confirms that survival, calcification, growth, development and abundance can all be negatively affected by ocean acidification, but the scale of response can vary greatly for different life stages, between taxonomic groups, and according to other environmental conditions, including food availability.
The input of nutrients into Icelandic waters is not considered an important pressure because of the limited agriculture and small human population. Measurements show low concentration levels of heavy metals and persistent organic pollutants, and the concentration of most contaminants are declining. The OSPAR area I (Arctic waters, which includes the Icelandic Waters ecoregion) has no current eutrophication issues.
The monitoring of plastic pollution has started recently, and compared to other ecoregions it is not considered a significant pressure in the Icelandic Waters ecoregion. The main source of plastic recorded in monitoring programmes originates from fishing (synthetic nets, lines, etc.).
Maritime transport is small within the Icelandic Waters ecoregion compared to many other ecoregions, mainly cargo (in the southwest) and fishing vessels, and in later years cruise ships. In order to reduce the risk to ecologically fragile areas from maritime traffic (sinking, stranding, oil spillage, ballast water), ship lanes have been moved further out from the coast.