MODEL SIMULATIONS
; RECONSTRUCTION
; WATER
; NITROGEN
; LEVEL
; ICE
; CYANOBACTERIA
; VARIABILITY
; ENSEMBLE
; INFLOWS
WOS学科分类:
Meteorology & Atmospheric Sciences
WOS研究方向:
Meteorology & Atmospheric Sciences
英文摘要:
In the Baltic Sea hypoxia has been increased considerably since the first oxygen measurements became available in 1898. In 2016 the annual maximum extent of hypoxia covered an area of the sea bottom of about 70,000km(2), comparable with the size of Ireland, whereas 150years ago hypoxia was presumably not existent or at least very small. The general view is that the increase in hypoxia was caused by eutrophication due to anthropogenic riverborne nutrient loads. However, the role of changing climate, e.g. warming, is less clear. In this study, different causes of expanding hypoxia were investigated. A reconstruction of the changing Baltic Sea ecosystem during the period 1850-2008 was performed using a coupled physical-biogeochemical ocean circulation model. To disentangle the drivers of eutrophication and hypoxia a series of sensitivity experiments was carried out. We found that the decadal to centennial changes in eutrophication and hypoxia were mainly caused by changing riverborne nutrient loads and atmospheric deposition. The impacts of other drivers like observed warming and eustatic sea level rise were comparatively smaller but still important depending on the selected ecosystem indicator. Further, (1) fictively combined changes in air temperature, cloudiness and mixed layer depth chosen from 1904, (2) exaggerated increases in nutrient concentrations in the North Sea and (3) high-end scenarios of future sea level rise may have an important impact. However, during the past 150years hypoxia would not have been developed if nutrient conditions had remained at pristine levels.
1.Leibniz Inst Balt Sea Res Warnemunde, Dept Phys Oceanog & Instrumentat, D-18119 Rostock, Germany 2.Swedish Meteorol & Hydrol Inst, Dept Res & Dev, S-60176 Norrkoping, Sweden 3.Swedish Meteorol & Hydrol Inst, Climate Informat & Stat, S-60176 Norrkoping, Sweden 4.Tallinn Univ Technol, Dept Marine Syst, EE-12618 Tallinn, Estonia 5.Univ Tecn Lisboa, Dept Mech Engn, P-1049001 Lisbon, Portugal
Recommended Citation:
Meier, H. E. M.,Eilola, K.,Almroth-Rosell, E.,et al. Disentangling the impact of nutrient load and climate changes on Baltic Sea hypoxia and eutrophication since 1850[J]. CLIMATE DYNAMICS,2019-01-01,53(1-2):1145-1166