Abstract. In this paper we provide an overview of new knowledge on oxygen depletion (hypoxia) and related phenomena in aquatic systems resulting from the EU-FP7 project HYPOX ("In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and landlocked water bodies", www.hypox.net). In view of the anticipated oxygen loss in aquatic systems due to eutrophication and climate change, HYPOX was set up to improve capacities to monitor hypoxia as well as to understand its causes and consequences.Temporal dynamics and spatial patterns of hypoxia were analyzed in field studies in various aquatic environments, including the Baltic Sea, the Black Sea, Scottish and Scandinavian fjords, Ionian Sea lagoons and embayments, and Swiss lakes. Examples of episodic and rapid (hours) occurrences of hypoxia, as well as seasonal changes in bottom-water oxygenation in stratified systems, are discussed. Geologically driven hypoxia caused by gas seepage is demonstrated. Using novel technologies, temporal and spatial patterns of watercolumn oxygenation, from basin-scale seasonal patterns to meter-scale sub-micromolar oxygen distributions, were resolved. Existing multidecadal monitoring data were used to demonstrate the imprint of climate change and eutrophication on long-term oxygen distributions. Organic and inorganic proxies were used to extend investigations on past oxygen conditions to centennial and even longer timescales that cannot be resolved by monitoring. The effects of hypoxia on faunal communities and biogeochemical processes were also addressed in the project. An investigation of benthic fauna is presented as an example of hypoxia-devastated benthic communities that slowly recover upon a reduction in eutrophication in a system where naturally occurring hypoxia overlaps with anthropogenic hypoxia. Biogeochemical investigations reveal that oxygen intrusions have a strong effect on the microbially mediated redox cycling of elements. Observations and modeling studies of the sediments demonstrate the effect of seasonally changing oxygen conditions on benthic mineralization pathways and fluxes. Data quality and access are crucial in hypoxia research. Technical issues are therefore also addressed, including the availability of suitable sensor technology to resolve the gradual changes in bottom-water oxygen in marine systems that can be expected as a result of climate change. Using cabled observatories as examples, we show how the benefit of continuous oxygen monitoring can be maximized by adopting proper quality control. Finally, we discuss strategies for state-of-the-art data archiving and dissemination in compliance with global standards, and how ocean observations can contribute to global earth observation attempts.
In a 2.5-year-long environmental engineering experiment in the By Fjord, surface water was pumped into the deepwater where the frequency of deepwater renewals increased by a factor of 10. During the experiment, the deepwater became long-term oxic, and nitrate became the dominating dissolved inorganic nitrogen component. The amount of phosphate in the water column decreased by a factor of 5 due to the increase in flushing and reduction in the leakage of phosphate from the sediments when the sediment surface became oxidized. Oxygenation of the sediments did not increase the leakage of toxic metals and organic pollutants. The bacterial community was the first to show changes after the oxygenation, with aerobic bacteria also thriving in the deepwater. The earlier azoic deepwater bottom sediments were colonized by animals. No structural difference between the phytoplankton communities in the By Fjord and the adjacent Havsten Fjord, with oxygenated deepwater, could be detected during the experiment.Electronic supplementary materialThe online version of this article (doi:10.1007/s13280-014-0524-9) contains supplementary material, which is available to authorized users.
COPD and obstructive sleep apnoea (OSA) are highly prevalent and different clinical COPD phenotypes that influence the likelihood of comorbid OSA. The increased lung volumes and low body mass index (BMI) associated with the predominant emphysema phenotype protects against OSA whereas the peripheral oedema and higher BMI often associated with the predominant chronic bronchitis phenotype promote OSA. The diagnosis of OSA in COPD patients requires clinical awareness and screening questionnaires which may help identify patients for overnight study. Management of OSA-COPD overlap patients differs from COPD alone and the survival of overlap patients treated with nocturnal positive airway pressure is superior to those untreated. Sleep-related hypoventilation is common in neuromuscular disease and skeletal disorders because of the effects of normal sleep on ventilation and additional challenges imposed by the underlying disorders. Hypoventilation is first seen during rapid eye movement (REM) sleep before progressing to involve non-REM sleep and wakefulness. Clinical presentation is nonspecific and daytime respiratory function measures poorly predict nocturnal hypoventilation. Monitoring of respiration and carbon dioxide levels during sleep should be incorporated in the evaluation of high-risk patient populations and treatment with noninvasive ventilation improves outcomes.
ABSTRACT:In this paper we reconstructed river runoff to the Baltic Sea since 1500 using temperature and atmospheric circulation indices, showing the important atmospheric processes for river runoff in different regions. Runoff appears to be strongly linked to temperature, wind and rotational circulation components in the northern region and Gulf of Finland, but more associated with rotational and deformation circulation components in the south. No significant long-term change has been detected in total river runoff to the Baltic Sea for 500 years, although decadal and regional variability is large. Analysis of runoff sensitivity to temperature shows that the south region may become drier with rising air temperatures. This is in contrast to the north region and Gulf of Finland where warmer temperatures are associated with more river runoff. Over the past 500 years the total river runoff to the Baltic Sea has decreased by 3% (450 m 3 /s) per degree Celsius increase.
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