Stratification-induced hypoxia as a structuring factor of macrozoobenthos in the open Gulf of Finland (Baltic Sea)

Laine, Ari O.; Andersin, Ann-Britt; Leiniö, Sari; Zuur, Alain F.

doi:10.1016/j.seares.2006.08.003

Cited by 58 publications

(40 citation statements)

References 37 publications

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“…Unusually high bottom layer salinities and thick hypoxic bottom layer were observed in the Gulf of Finland in 2016. This result is in line with the tendencies after the previous MBIs: stronger stratification and increased hypoxia were observed in the Northeastern Baltic Sea since the mid-1990s (Laine et al, 2007;Liblik and Lips, 2011;Lehtoranta et al, 2017). In the present study, we used only oxygen measurements for the estimates of changes in the oxygen content.…”

Section: Discussionsupporting

confidence: 83%

Propagation of Impact of the Recent Major Baltic Inflows From the Eastern Gotland Basin to the Gulf of Finland

et al. 2018

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Section: Discussionsupporting

confidence: 83%

Propagation of Impact of the Recent Major Baltic Inflows From the Eastern Gotland Basin to the Gulf of Finland

et al. 2018

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“…Such factors include the isolation of deeper water masses by stratification of the water column or geographical confinement, and the advection of low-oxygen water from other sources (see . In parts of the Baltic Sea, hypoxia during the Holocene and the modern era has been closely linked to water-column stratification caused by climate-related fluctuations in river runoff and saltwater inflows, although eutrophication has also been an important driver, particularly during the last 50 years (Laine et al, 2007;Zillén et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Historical records of coastal eutrophication-induced hypoxia

Jorissen²,

et al. 2009

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Abstract. Under certain conditions, sediment cores from coastal settings subject to hypoxia can yield records of environmental changes over time scales ranging from decades to millennia, sometimes with a resolution of as little as a few years. A variety of biological and geochemical indicators (proxies) derived from such cores have been used to reconstruct the development of eutrophication and hypoxic conditions over time. Those based on (1) the preserved remains of benthic organisms (mainly foraminiferans and ostracods), (2) sedimentary features (e.g. laminations) and (3) sediment chemistry and mineralogy (e.g. presence of sulphides and redox-sensitive trace elements) reflect conditions at or close to the seafloor. Those based on (4) the preserved remains of planktonic organisms (mainly diatoms and dinoflagellates), (5) pigments and lipid biomarkers derived from prokaryotes and eukaryotes and (6) organic C, N and their stable isotope ratios reflect conditions in the water column. However, the interpretation of these indicators is not straightforward. A central difficulty concerns the fact that hypoxia is strongly correlated with, and often induced by, organic enrichment caused by eutrophication, making it difficult to separate the effects of these phenomena in sediment records. The problem is compounded by the enhanced preservation in anoxic and hypoxic sediments of organic microfossils and biomarkers indicating eutrophication. The use of hypoxiaCorrespondence to: A. J. Gooday (ang@noc.soton.ac.uk) specific proxies, such as the trace metals molybdenum and rhenium and the bacterial biomarker isorenieratene, together with multi-proxy approaches, may provide a way forward. All proxies of bottom-water hypoxia are basically qualitative; their quantification presents a major challenge to which there is currently no satisfactory solution. Finally, it is important to separate the effects of natural ecosystem variability from anthropogenic effects. Despite these problems, in the absence of historical data for dissolved oxygen concentrations, the analysis of sediment cores can provide plausible reconstructions of the temporal development of humaninduced hypoxia, and associated eutrophication, in vulnerable coastal environments.

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“…Zorita and Laine 2000). On the basis of monitoring data for the period 1965-2000, Laine et al (2007) found a continuous decrease in salinity and density stratification until the early 1990s, after which there was a slight increase. Based on independent data for 1987-2008, Liblik and Lips (2011 found that the deep salinities in summer increased after the 1993 major inflow by about 2 g kg −1 .…”

Section: 3mentioning

confidence: 98%

“…Despite the increased mean stratification strength and more frequent occurrence of hypoxia events (see Chap. 18), at the annual scale ventilation of deep waters is still effective and the annual mean oxygen concentrations remain higher than during the 1960s and 1970s (Laine et al 2007). This can be explained by decreased sea-ice cover (see Chap.…”

Section: 3mentioning

confidence: 99%

Recent Change—Marine Circulation and Stratification

Elken

Lehmann

Myrberg

2015

Regional Climate Studies

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This chapter describes recent change in the circulation and stratification of the Baltic Sea. A recent warming trend in sea-surface waters has been clearly demonstrated by in situ measurements, remote sensing data and numerical models. Trends in sea-surface temperature (SST) for the past three to four decades based on remote sensing data generally agree with trends determined from in situ observations. Models suggest the current warming within the Baltic Sea lies within the range experienced during the past 500 years. The salinity and stratification of the deep waters are strongly linked to the major inflows of North Sea water that occur sporadically and bring high-saline water into the deep layers of the Baltic Sea. The major inflows normally occur during winter and spring and bring cold oxygen-rich waters into the deep basins. Since 1996, large inflows have also occurred during summer, bringing in warm low-oxygen water. IntroductionChanges in thermohaline characteristics and stratification of the water column are usually analysed on the basis of data from repeat hydrographic observations, originating from shipborne monitoring programmes and/or permanent coastal and offshore oceanographic stations. Such datasets are described in recent books by Feistel et al. (2008) and Leppäranta and Myrberg (2009). In situ observations are often irregular in space and time, especially for offshore areas; therefore, trends and variability in the ocean state can only be determined by careful pre-processing of the data to address issues such as data homogenisation and the suppression of aliasing errors. In recent decades, horizontal undersampling by in situ measurements has been partially offset by the remote sensing of sea-surface properties from satellites; with these data free of spatial aliasing errors due to their high horizontal resolution. Satellite-derived cloud-free products for sea-surface temperature (SST) have been reasonably accurate since the 1980s. Many of the papers published over the past decade that address trends and variability in the circulation and stratification of the Baltic Sea are based on remote sensing data, often in combination with in situ observations and the results of numerical modelling. Improvements in the physical and numerical features of the models, accompanied by model validation studies, have increased confidence in the realism of the model results. Models provide dynamically balanced gridded datasets over decades or longer, including information for 'noisy' variables such as currents, transport and mixing fluxes. This chapter analyses the recent peer-reviewed literature, extending the findings from earlier review (Box 7.1).

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Stratification-induced hypoxia as a structuring factor of macrozoobenthos in the open Gulf of Finland (Baltic Sea)

Cited by 58 publications

References 37 publications

Propagation of Impact of the Recent Major Baltic Inflows From the Eastern Gotland Basin to the Gulf of Finland

Propagation of Impact of the Recent Major Baltic Inflows From the Eastern Gotland Basin to the Gulf of Finland

Historical records of coastal eutrophication-induced hypoxia

Recent Change—Marine Circulation and Stratification

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