Climatic factors in the Atlantic control the oceanographic and ecological changes in the Baltic Sea

Hänninen, Jari; Vuorinen, Ilppo; Hjelt, Pekka

doi:10.4319/lo.2000.45.3.0703

Cited by 140 publications

(133 citation statements)

References 19 publications

Supporting

Mentioning

127

Contrasting

Unclassified

Order By: Relevance

“…It is possible that various chemicals of municipal, industrial, or agricultural origin are involved in the formation of gonad abnormalities in the Baltic herring, and some of them could be related to the changes of the Baltic ecosystem and develop in one way or another as a response to declining salinity that has taken place during the past 30 years (Hänninen et al 2000;. Salinity may affect the hormonal system and reproduction of fish (Billard et al 1981), but most likely a euryhaline species like the Baltic herring is able to adjust to variation of salinity, which is a typical feature of the Baltic Sea.…”

Section: Possible Causes Of Gonad Malformationsmentioning

confidence: 99%

Morphological abnormalities in gonads of the Baltic herring (Clupea harengus membras): Description of types and prevalence in the northern Baltic Sea

Rajasilta

Elfving

Hänninen

et al. 2015

Ambio

Self Cite

View full text Add to dashboard Cite

Due to heavy anthropogenic influence and variation of the environmental conditions in the Baltic Sea, reproductive disorders are becoming a major environmental concern. We show here an increasing prevalence of gonadal malformations in the Baltic herring (Clupea harengus membras), a key species of the Baltic ecosystem and important in commercial fishery. During 1987-2014, the spawning herring population in the Archipelago Sea (AS) (North Baltic Sea, Finland) was monitored annually and analyzed for gross morphology of the gonads [total number (n) of analyzed fish = 38 284]. Four different types of malformations were repeatedly found and named as asymmetric, rudimentary, segmented, and branched gonads, but also hermaphroditic gonads and miscellaneous (unidentified) disorders were recorded. In 2013, additional samplings (n of fish analyzed = 541) showed similar malformations in herring from the Bothnian Sea. In some gonad types, histological examination revealed disintegration of seminiferous tubules and hyperplasia of the interstitial tissue. In 2014, the overall prevalence of malformations was still relatively low in the AS (frequency = 0-3.4 %; n = 750) and had apparently minimal effect on population recruitment. However, an increasing trend in the time-series (GLM; F = 32.65; p\0.001) and a significantly higher prevalence in the Bothnian Sea (frequency = 0.7-5.0 %; n = 541; v 2 = 6.24; p\0.05) suggest that gonadal malformations may become a new threat for fish in the Baltic Sea. The observed gonad atrophies may be due to environmental endocrine disruption; however, also other explanations may exist and potential explanations are discussed.

show abstract

Section: Possible Causes Of Gonad Malformationsmentioning

confidence: 99%

Morphological abnormalities in gonads of the Baltic herring (Clupea harengus membras): Description of types and prevalence in the northern Baltic Sea

Rajasilta

Elfving

Hänninen

et al. 2015

Ambio

Self Cite

View full text Add to dashboard Cite

show abstract

“…We also investigated the annual average temperatures against the NAO indices ( Fig. 3) (Hänninen et al, 2000;Osborn, 2004Osborn, , 2006Osborn, , 2011 and found that on average, lower temperatures are connected to highest negative NAO values, and vice versa (visible also in the 5-year running mean shown in Figs. 2 and 3) (Lehmann et al, 2011).…”

Section: Long-term Changes In Atmospheric Temperaturesmentioning

confidence: 99%

100 years of atmospheric and marine observations at the Finnish Utö Island in the Baltic Sea

et al. 2018

View full text Add to dashboard Cite

Abstract. The Utö Atmospheric and Marine Research Station introduced in this paper is located on Utö Island (59 • 46.84 N, 21 • 22.13 E) at the outer edge of the Archipelago Sea, by the Baltic Sea towards the Baltic Proper. Meteorological observations at the island started in 1881 and vertical profiling of seawater temperature and salinity in 1900. Since 1980, the number of observations at Utö has rapidly increased, with a large number of new meteorological, air quality, aerosol, optical and greenhouse gas parameters, and recently, a variety of marine observations. In this study, we analyze long-term changes of atmospheric temperature, cloudiness, sea salinity, temperature and ice cover. Our main dataset consists of 248 367 atmospheric temperature observations, 1632 quality-assured vertical seawater temperature and salinity profiles and 8565 ice maps, partly digitized for this project. We also use North Atlantic Oscillation (NAO), major Baltic inflow (MBI) and Baltic Sea river runoff data from the literature as reference variables to our data. Our analysis is based on a statistical method utilizing a dynamic linear model. The results show an increase in the atmospheric temperature at Utö, but the increase is significantly smaller than on land areas and has taken place only since the early 1980s, with a rate of 0.4 • C decade −1 during the last 35 years. We also see an increase in seawater temperatures, especially on the surface, with an increase of 0.3 • C decade −1 for the last 100 years. In deeper water layers, the increase is smaller and influenced by vertical mixing, which is modulated by inflow of saline water from the North Sea and freshwater inflow from rivers and by wind-driven processes influenced by the local bathymetry. The date when air temperature in the spring exceeds +5 • C became 5 days earlier from the period 1951-1980 to the period 1981-2010 and the date when sea surface water temperature exceeds +4 • C changed to 9 days earlier. Sea ice cover duration at Utö shows a decrease of approximately 50 % during the last 35 years. Based on the combined results, it is possible that the climate at Utö has changed into a new phase, in which the sea ice no longer reduces the local temperature increase caused by the global warming.

show abstract

“…Kau Bay) or the North Atlantic Oscillation (e.g. Baltic Sea) (Hanninen et al, 2000;). Advection of North Sea water into the Baltic Sea anoxic basins results in a cascade of biogeochemical reactions with major consequences for food web structure and ecosystem functioning.…”

Section: Hypoxia In Semi-enclosed Seas and Basinsmentioning

confidence: 99%

Natural and human-induced hypoxia and consequences for coastal areas: synthesis and future development

et al. 2010

View full text Add to dashboard Cite

Abstract. Hypoxia has become a world-wide phenomenon in the global coastal ocean and causes a deterioration of the structure and function of ecosystems. Based on the collective contributions of members of SCOR Working Group #128, the present study provides an overview of the major aspects of coastal hypoxia in different biogeochemical provinces, including estuaries, coastal waters, upwelling areas, fjords and semi-enclosed basins, with various external forcings, ecosysCorrespondence to: J. Zhang (jzhang@sklec.ecnu.edu.cn) tem responses, feedbacks and potential impact on the sustainability of the fishery and economics. The obvious external forcings include freshwater runoff and other factors contributing to stratification, organic matter and nutrient loadings, as well as exchange between coastal and open ocean water masses. Their different interactions set up mechanisms that drive the system towards hypoxia. Coastal systems also vary in their relative susceptibility to hypoxia depending on their physical and geographic settings. It is understood that coastal hypoxia has a profound impact on the sustainability of ecosystems, which can be seen, for example, by the change in the food-web structure and system function; other Published by Copernicus Publications on behalf of the European Geosciences Union. 1444 J. Zhang et al.: Natural and human-induced hypoxia and consequences for coastal areas influences include compression and loss of habitat, as well as changes in organism life cycles and reproduction. In most cases, the ecosystem responds to the low dissolved oxygen in non-linear ways with pronounced feedbacks to other compartments of the Earth System, including those that affect human society. Our knowledge and previous experiences illustrate that there is a need to develop new observational tools and models to support integrated research of biogeochemical dynamics and ecosystem behavior that will improve confidence in remediation management strategies for coastal hypoxia.

show abstract

Climatic factors in the Atlantic control the oceanographic and ecological changes in the Baltic Sea

Cited by 140 publications

References 19 publications

Morphological abnormalities in gonads of the Baltic herring (Clupea harengus membras): Description of types and prevalence in the northern Baltic Sea

Morphological abnormalities in gonads of the Baltic herring (Clupea harengus membras): Description of types and prevalence in the northern Baltic Sea

100 years of atmospheric and marine observations at the Finnish Utö Island in the Baltic Sea

Natural and human-induced hypoxia and consequences for coastal areas: synthesis and future development

Contact Info

Product

Resources

About