Plastic debris composition and concentration in the Arctic Ocean, the North Sea and the Baltic Sea.

Neuston samples were collected with a Manta trawl in the rim of the Arctic Ocean, in the Northern Atlantic Ocean and the Baltic Sea at eleven coastal and open-sea locations. All samples contained plastics identified by FTIR microscopy. Altogether, 110 microplastics pieces were classified according to size, shape, and polymer type. The concentrations at the locations were generally low (x̅ = 0.06, SD ± 0.04 particles m-3) as compared to previous observations. The highest concentrations were found towards the Arctic Ocean, while those in the Baltic Sea were generally low. The most abundant polymer type was polyethylene. Detected particle types were mainly fragments. The number of films and fibers was very low. The mean particle size was 2.66 mm (SD ± 1.55 mm). Clustering analyses revealed that debris compositions in the sea regions had characteristic differences possibly reflecting the dependences between compositions, drifting distances, sinking rates, and local oceanographic conditions.

The importance of study duration and spatial scale in pathogen detection-evidence from a tick-infested island.

Ticks (Acari: Ixodoidea) are among the most common vectors of zoonotic pathogens worldwide. While research on tick-borne pathogens is abundant, few studies have thoroughly investigated small-scale spatial differences in their occurrence. Here, we used long-term cloth-dragging data of Ixodes ricinus and its associated, known and putative pathogens (Borrelia burgdorferi s.l., Borrelia miyamotoi, Anaplasma phagocytophilum, Rickettsia spp., Candidatus Neoehrlichia mikurensis, Bartonella spp., Babesia spp., and tick-borne encephalitis virus, TBEV) from a small, well-studied island in southwestern Finland to analyze potential temporal and spatial differences in pathogen prevalence and diversity between and within different biotopes. We found robust evidence indicating significant dissimilarities in B. burgdorferi s.l., A. phagocytophilum, Rickettsia, and Ca. N. mikurensis prevalence, even between proximal study areas on the island. Moreover, during the 6 years of the ongoing study, we witnessed the possible emergence of TBEV and Ca. N. mikurensis on the island. Finally, the stable occurrence of a protozoan pathogen that has not been previously reported in Finland, Babesia venatorum, was observed on the island. Our study underlines the importance of detailed, long-term tick surveys for public health. We propose that by more precisely identifying different environmental factors associated with the emergence and upkeep of enzootic pathogen populations through rigorous longitudinal surveys, we may be able to create more accurate models for both current and future pathogen distributions.

Tick-borne pathogens in Finland: comparison of Ixodes ricinus and I. persulcatus in sympatric and parapatric areas.

BACKGROUND: Almost 3500 tick samples, originally collected via a nationwide citizen science campaign in 2015, were screened to reveal the prevalence and distribution of a wide spectrum of established and putative tick-borne pathogens vectored by Ixodes ricinus and I. persulcatus in Finland. The unique geographical distribution of these two tick species in Finland allowed us to compare pathogen occurrence between an I. ricinus-dominated area (southern Finland), an I. persulcatus-dominated area (northern Finland), and a sympatric area (central Finland). RESULTS: Of the analysed ticks, almost 30% carried at least one pathogen and 2% carried more than one pathogen. A higher overall prevalence of tick-borne pathogens was observed in I. ricinus than in I. persulcatus: 30.0% (604/2014) versus 24.0% (348/1451), respectively. In addition, I. ricinus were more frequently co-infected than I. persulcatus: 2.4% (49/2014) versus 0.8% (12/1451), respectively. Causative agents of Lyme borreliosis, i.e. bacterial genospecies in Borrelia burgdorferi (sensu lato) group, were the most prevalent pathogens (overall 17%). "Candidatus Rickettsia tarasevichiae" was found for the first time in I. ricinus ticks and in Finnish ticks in general. Moreover, Babesia divergens, B. venatorum and "Candidatus Neoehrlichia mikurensis" were reported for the first time from the Finnish mainland. CONCLUSIONS: The present study provides valuable information on the prevalence and geographical distribution of various tick-borne pathogens in I. ricinus and I. persulcatus ticks in Finland. Moreover, this comprehensive subset of ticks revealed the presence of rare and potentially dangerous pathogens. The highest prevalence of infected ticks was in the I. ricinus-dominated area in southern Finland, while the prevalence was essentially equal in sympatric and I. persulcatus-dominated areas. However, the highest infection rates for both species were in areas of their dominance, either in south or north Finland.

Crowdsourcing-based nationwide tick collection reveals the distribution of Ixodes ricinus and I. persulcatus and associated pathogens in Finland.

A national crowdsourcing-based tick collection campaign was organized in 2015 with the objective of producing novel data on tick distribution and tick-borne pathogens in Finland. Nearly 20 000 Ixodes ticks were collected. The collected material revealed the nationwide distribution of I. persulcatus for the first time and a shift northwards in the distribution of I. ricinus in Finland. A subset of 2038 tick samples containing both species was screened for Borrelia burgdorferi sensu lato (the prevalence was 14.2% for I. ricinus and 19.8% for I. persulcatus), B. miyamotoi (0.2% and 0.4%, respectively) and tick-borne encephalitis virus (TBEV; 0.2% and 3.0%, respectively). We also report new risk areas for TBEV in Finland and, for the first time, the presence of B. miyamotoi in ticks from mainland Finland. Most importantly, our study demonstrates the overwhelming power of citizen science in accomplishing a collection effort that would have been impossible with the scientific community alone.

Tick-borne bacterial pathogens in southwestern Finland.

BACKGROUND: Ixodes ricinus and Ixodes persulcatus are the main vectors of Lyme borreliosis spirochetes and several other zoonotic bacteria in northern Europe and Russia. However, few studies screening bacterial pathogens in Finnish ticks have been conducted. Therefore, reports on the occurrence and prevalence of several bacterial pathogens detected from ticks elsewhere in Europe and Russia are altogether missing from Finland. The main aim of the current study was to produce novel data on the occurrence and prevalence of several tick-borne bacterial pathogens in ticks collected from southwestern Finland. METHODS: Ticks were collected in 2013-2014 by blanket dragging from 25 localities around southwestern Finland, and additionally from a dog in Lempäälä. Collected ticks were molecularly identified and screened for Borrelia burgdorferi s.l., Borrelia miyamotoi, Rickettsia, Bartonella and Candidatus Neoehrlichia mikurensis using quantitative PCR. Furthermore, detected Rickettsia spp. were sequenced using conventional PCR to determine species. RESULTS: A total of 3169 ticks in 1174 DNA samples were screened for the listed pathogens. The most common bacteria detected was B. burgdorferi (s.l.) (18.5 % nymphal and 23.5 % adult ticks), followed by Rickettsia spp. (1.1 %; 5.1 %) and B. miyamotoi (0.51 %; 1.02 %). B. miyamotoi and Rickettsia spp. were also detected in larval samples (minimum infection rates 0.31 % and 0.21 %, respectively). Detected Rickettsia spp. were identified by sequencing as R. helvetica and R. monacensis. All screened samples were negative for Bartonella spp. and Ca. N. mikurensis. CONCLUSIONS: In the current study we report for the first time the presence of Rickettsia in Finnish ticks. Furthermore, Rickettsia spp. and B. miyamotoi were found from larval tick samples, emphasizing the importance they may have as vectors of these pathogens. Comparisons of tick density estimates and B. burgdorferi (s.l.) prevalence made between the current study and a previous study conducted in 2000 in ten out of the 25 study localities suggest that an increase in tick abundance and B. burgdorferi (s.l.) prevalence has occurred in at least some of the study localities.

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

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; χ (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.

Assessing the abundance, seasonal questing activity, and Borrelia and tick-borne encephalitis virus (TBEV) prevalence of Ixodes ricinus ticks in a Lyme borreliosis endemic area in Southwest Finland.

Studies have revealed that Ixodes ricinus (Acari: Ixodidae) have become more abundant and their geographical distribution extended northwards in some Nordic countries during the past few decades. However, ecological data of tick populations in Finland are sparse. In the current study, I. ricinus abundance, seasonal questing activity, and their Borrelia spp. and tick-borne encephalitis virus (TBEV) prevalence were evaluated in a Lyme borreliosis endemic area in Southwest Finland, Seili Island, where a previous study mapping tick densities was conducted 12 years earlier. A total of 1940 ticks were collected from five different biotopes by cloth dragging during May-September 2012. The overall tick density observed was 5.2 ticks/100m(2) for nymphs and adults. Seasonal questing activity of ticks differed between biotopes and life stages: bimodal occurrences were observed especially for nymphal and adult ticks in forested biotopes, while larvae in pastures exhibited mostly unimodal occurrence. Prevalence of Borrelia and TBEV in ticks was evaluated using conventional and real-time PCR. All samples were negative for TBEV. Borrelia prevalence was 25.0% for adults (n=44) and the minimum infection rate (MIR) 5.6% for pooled nymph samples (191 samples, 1-14 individuals per sample; 30/191 positive). No Borrelia were detected in pooled larval samples (63 samples, 1-139 individuals per sample). Five species of Borrelia were identified from the samples: B. afzelii, B. burgdorferi s.s., B. garinii, B. valaisiana and B. miyamotoi. In Finland, B. valaisiana and B. miyamotoi have previously been reported from the Åland Islands but not from the mainland or inner archipelago. The results of the present study suggest an increase in I. ricinus abundance on the island.

Riverine tot-P loading and seawater concentrations in the Baltic Sea during the 1970s to 2000-transfer function modelling based on the total runoff.

The signal of climate through the North Atlantic Oscillation (NAO) extends to westerly weather and to the Baltic Sea river runoff (BSRR) and further to the salinity and the marine fauna in the Baltic Sea. Our working hypothesis was that increased BSRR should also lead to increasing nutrient concentrations in the seawater. In rivers, transfer function (TF) models of the loading were constructed by time series of BSRR and tot-P concentrations. Based on the loading time series, we modelled, to our knowledge, first time, seawater tot-P concentrations in both the Northern Baltic Proper and in the Gulf of Bothnia, both on the surface (0-20 m) and deeper (21-70 m) waters. Our results further suggest a unifying mechanism by the BSRR that could explain most prominent ecological changes observed in the Baltic Sea during and after the 1970s. Such changes are eutrophication (as in this paper) and decreasing salinity and growth and reproduction of marine fauna, all of which have been separately described as due to different causes. BSRR is crucial when possible future developments of the Baltic Sea environment are considered because a general opinion exists that the rainfall (and the BSRR) is expected to increase in pace with proceeding climate change.

Scenario simulations of future salinity and ecological consequences in the Baltic Sea and adjacent North Sea areas-implications for environmental monitoring.

Substantial ecological changes occurred in the 1970s in the Northern Baltic during a temporary period of low salinity (S). This period was preceded by an episodic increase in the rainfall over the Baltic Sea watershed area. Several climate models, both global and regional, project an increase in the runoff of the Northern latitudes due to proceeding climate change. The aim of this study is to model, firstly, the effects on Baltic Sea salinity of increased runoff due to projected global change and, secondly, the effects of salinity change on the distribution of marine species. The results suggest a critical shift in the S range 5-7, which is a threshold for both freshwater and marine species distributions and diversity. We discuss several topics emphasizing future monitoring, modelling, and fisheries research. Environmental monitoring and modelling are investigated because the developing alternative ecosystems do not necessarily show the same relations to environment quality factors as the retiring ones. An important corollary is that the observed and modelled S changes considered together with species' ranges indicate what may appear under a future climate. Consequences could include a shift in distribution areas of marine benthic foundation species and some 40-50 other species, affiliated to these. This change would extend over hundreds of kilometres, in the Baltic Sea and the adjacent North Sea areas. Potential cascading effects, in coastal ecology, fish ecology and fisheries would be extensive, and point out the necessity to develop further the "ecosystem approach in the environmental monitoring".

Prevalence of granulocytic Ehrlichia and Borrelia burgdorferi sensu lato in Ixodes ricinus ticks collected from Southwestern Finland and from Vormsi Island in Estonia.

Altogether, 343 adult and 111 nymphal Ixodes ricinus ticks collected from parks in Turku and suburban and rural islands of the Turku archipelago, Finland, and 100 adult I. ricinus ticks collected from Vormsi Island, Estonia, were included in this study. Using the polymerase chain reaction the ticks were examined for 16S rDNA of the Ehrlichia phagocytophila genogroup and for Borrelia burgdorferi sensu lato recA and flagellin genes. None of the Finnish ticks was found to be infected with E. phagocytophila, whereas 3% of the Estonian ticks were positive for this organism. The rate of Finnish ticks infected with B. burgdorferi sensu lato varied from 0% to 11.6% (mean 5%; 9% for adult and 4% for nymphal ticks). The corresponding rate for Estonian ticks was 15%. Borrelia afzelii was the most common genospecies in both Finnish (2.6%) and Estonian (12%) ticks. B. burgdorferi sensu stricto was detected in 2.0% of the Finnish ticks, but in none of the Estonian ticks. These results suggest that the E. phagocytophila genogroup is very rare in Finnish ticks, although the ticks were collected from an area endemic for Lyme borreliosis. In Estonia, E. phagocytophila is found in ticks and may cause disease.