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  • Qi, Lu; Vogel, Alexander L.; Esmaeilirad, Sepideh; Cao, Liming; Zheng, Jing; Jaffrezo, Jean-Luc; Fermo, Paola; Kasper-Giebl, Anne; Dällenbach, Kaspar; Chen, Mindong; Ge, Xinlei; Baltensperger, Urs; Prevot, Andre S. H.; Slowik, Jay G. (2020)
    The aerosol mass spectrometer (AMS), combined with statistical methods such as positive matrix factorization (PMF), has greatly advanced the quantification of primary organic aerosol (POA) sources and total secondary organic aerosol (SOA) mass. However, the use of thermal vaporization and electron ionization yields extensive thermal decomposition and ionization-induced fragmentation, which limit chemical information needed for SOA source apportionment. The recently developed extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF) provides mass spectra of the organic aerosol fraction with a linear response to mass and no thermal decomposition or ionization-induced fragmentation. However, the costs and operational requirements of online instruments make their use impractical for long-term or spatially dense monitoring applications. This challenge was overcome for AMS measurements by measuring re-nebulized water extracts from ambient filter samples. Here, we apply the same strategy for EESI-TOF measurements of 1 year of 24 h filter samples collected approximately every fourth day throughout 2013 at an urban site. The nebulized water extracts were measured simultaneously with an AMS. The application of positive matrix factorization (PMF) to EESI-TOF spectra resolved seven factors, which describe water-soluble OA: less and more aged biomass burning aerosol (LABB(EESI) and MABB(EESI), respectively), cigarette-smoke-related organic aerosol, primary biological organic aerosol, biogenic secondary organic aerosol, and a summer mixed oxygenated organic aerosol factor. Seasonal trends and relative contributions of the EESI-TOF OA sources were compared with AMS source apportionment factors, measured water-soluble ions, cellulose, and meteorological data. Cluster analysis was utilized to identify key factor-specific ions based on PMF. Both LABB and MABB contribute strongly during winter. LABB is distinguished by very high signals from C6H10O5 (levoglucosan and isomers) and C8H12O6, whereas MABB is characterized by a large number of CxHyOz and CxHyOzN species of two distinct populations: one with low H : C and high O : C and the other with high H : C and low O : C. Two oxygenated summertime SOA sources were attributed to terpene-derived biogenic SOA, a major summertime aerosol source in central Europe. Furthermore, a primary biological organic aerosol factor was identified, which was dominated by plant-derived fatty acids and correlated with free cellulose. The cigarette-smoke-related factor contained a high contribution of nicotine and high abundance of organic nitrate ions with low m/z.
  • Novakovic, Bojan; Tsirvoulis, Georgios; Granvik, Mikael; Todovic, Ana (2017)
    We report the discovery of a new asteroid family among the dark asteroids residing in the Phocaea region the Tamara family. We make use of available physical data to separate asteroids in the region according to their surface reflectance properties, and establish the membership of the family. We determine the slope of the cumulative magnitude distribution of the family, and find it to be significantly steeper than the corresponding slope of all the asteroids in the Phocaea region. This implies that subkilometer dark Phocaeas are comparable in number to bright S-type objects, shedding light on an entirely new aspect of the composition of small Phocaea asteroids. We then use the Yarkovsky V-shape based method and estimate the age of the family to be 264 +/- 43Myr. Finally, we carry out numerical simulations of the dynamical evolution of the Tamara family. The results suggest that up to 50 Tamara members with absolute magnitude H <19.4 may currently be found in the near-Earth region. Despite their relatively small number in the near-Earth space, the rate of Earth impacts by small, dark Phocaeas is non-negligible.
  • Macias-Hernandez, Nuria; Ramos, Cândida; Domènech, Marc; Febles, Sara; Santos, Irene; Arnedo, Miquel A.; Borges, Paulo A. V.; Emerson, Brent C.; Cardoso, Pedro (2020)
    Background There is an increasing demand for databases including species trait information for biodiversity and community ecology studies. The existence of trait databases is useful for comparative studies within taxa or geographical regions, but there is low availability of databases for certain organisms. Here we present an open access functional trait database for spiders from Macaronesia and the Iberian Peninsula, recording several morphological and ecological traits related to the species life histories, microhabitat and trophic preferences. New information We present a database that includes 12 biological traits for 506 spider species present in natural forests of the Iberian Peninsula (Spain) and three Macaronesian archipelagoes (Azores, Madeira and Canary Islands). The functional trait database consists of two sections: 1. individual-level data for six morphological traits (total body size, prosoma length, prosoma width, prosoma height, tibia I length and fang length), based on direct measurements of 2844 specimens of all spider species; and 2. species-level aggregate data for 12 traits (same 6 morphological traits as in the previous section plus dispersal ability, vertical stratification, circadian activity, foraging strategy, trophic specialization and colonization status), based on either the average of the direct measurements or bibliographic searches. This functional trait database will serve as a data standard for currently ongoing analyses that require trait and functional diversity statistics.
  • Timberlake, Thomas P.; Cirtwill, Alyssa R.; Baral, Sushil C.; Bhusal, Daya R.; Devkota, Kedar; Harris-Fry, Helen A.; Kortsch, Susanne; Myers, Samuel S.; Roslin, Tomas; Saville, Naomi M.; Smith, Matthew R.; Strona, Giovanni; Memmott, Jane (2022)
    1. Smallholder farmers are some of the poorest and most food insecure people on Earth. Their high nutritional and economic reliance on home--grown produce makes them particularly vulnerable to environmental stressors such as pollinator loss or climate change which threaten agricultural productivity. Improving smallholder agriculture in a way that is environmentally sustainable and resilient to climate change is a key challenge of the 21st century. 2. Ecological intensification, whereby ecosystem services are managed to increase agricultural productivity, is a promising solution for smallholders. However, smallholder farms are complex socio-ecological systems with a range of social, ecological and environmental factors interacting to influence ecosystem service provisioning. To truly understand the functioning of a smallholder farm and identify the most effective management options to support household food and nutrition security, a holistic, systems-based understanding is required. 3. In this paper, we propose a network approach to understand, visualise and model the complex interactions occurring among wild species, crops and people on smallholder farms. Specifically, we demonstrate how networks may be used to (a) identify wild species with a key role in supporting, delivering or increasing the resilience of an ecosystem service; (b) quantify the value of an ecosystem service in a way that is relevant to the food and nutrition security of smallholders; and (c) understand the social interactions that influence the management of shared ecosystem services. 4. Using a case study based on data from rural Nepal, we demonstrate how this framework can be used to connect wild plants, pollinators and crops to key nutrients consumed by humans. This allows us to quantify the nutritional value of an ecosystem service and identify the wild plants and pollinators involved in its provision, as well as providing a framework to predict the effects of environmental change on human nutrition. 5. Our framework identifies mechanistic links between ecosystem services and the nutrients consumed by smallholder farmers and highlights social factors that may influence the management of these services. Applying this framework to smallholder farms in a range of socio-ecological contexts may provide new, sustainable and equitable solutions to smallholder food and nutrition security.
  • Kuula, Juho; Lundbom, Jesper; Hakkarainen, Antti; Hovi, Petteri; Hauta-alus, Helena; Kaseva, Nina; Sandboge, Samuel; Björkqvist, Johan; Eriksson, Johan; Pietiläinen, Kirsi H.; Lundbom, Nina; Kajantie, Eero (2022)
    Preterm birth at very low birth weight (VLBW, < 1500 g) is associated with an accumulation of cardiovascular and metabolic risk factors from childhood at least to middle age. Small-scale studies suggest that this could partly be explained by increased visceral or ectopic fat. We performed magnetic resonance imaging on 78 adults born preterm at VLBW in Finland between 1978 and 1990 and 72 term same-sex siblings as controls, with a mean age of 29 years. We collected T1-weighted images from the abdomen, and magnetic resonance spectra from the liver, subcutaneous abdominal adipose tissue, and tibia. The adipose tissue volumes of VLBW adults did not differ from their term siblings when adjusting for age, sex, and maternal and perinatal factors. The mean differences were as follows: subcutaneous - 0.48% (95% CI - 14.8%, 16.3%), visceral 7.96% (95% CI - 10.4%, 30.1%), and total abdominal fat quantity 1.05% (95% CI - 13.7%, 18.4%). Hepatic triglyceride content was also similar. VLBW individuals displayed less unsaturation in subcutaneous adipose tissue (- 4.74%, 95% CI - 9.2%, - 0.1%) but not in tibial bone marrow (1.68%, 95% CI - 1.86%, 5.35%). VLBW adults displayed similar adipose tissue volumes and hepatic triglyceride content as their term siblings. Previously reported differences could thus partly be due to genetic or environmental characteristics shared between siblings. The VLBW group displayed less unsaturation in subcutaneous abdominal adipose tissue, suggesting differences in its metabolic activity and energy storage.
  • Kemppainen, Petri; Husby, Arild (2018)
    A fundamental assumption in quantitative genetics is that traits are controlled by many loci of small effect. Using genomic data, this assumption can be tested using chromosome partitioning analyses, where the proportion of genetic variance for a trait explained by each chromosome (h(c)(2)), is regressed on its size. However, as h(c)(2)-estimates are necessarily positive (censoring) and the variance increases with chromosome size (heteroscedasticity), two fundamental assumptions of ordinary least squares (OLS) regression are violated. Using simulated and empirical data we demonstrate that these violations lead to incorrect inference of genetic architecture. The degree of bias depends mainly on the number of chromosomes and their size distribution and is therefore specific to the species; using published data across many different species we estimate that not accounting for this effect overall resulted in 28% false positives. We introduce a new and computationally efficient resampling method that corrects for inflation caused by heteroscedasticity and censoring and that works under a large range of dataset sizes and genetic architectures in empirical datasets. Our new method substantially improves the robustness of inferences from chromosome partitioning analyses.
  • da Silva, Flavia G.; Formo, Eric; Camargo, Pedro H. C. (2022)
    Gold nanoparticles (Au NPs) have been extensively used as artificial enzymes, but their performance is still limited. We address this challenge by focusing on multimetallic nanorattles comprising an Au core inside a bimetallic AgAu shell, separated by a void (Au@AgAu NRs). They were prepared by a galvanic replacement approach and contained an ultrathin and porous shell comprising an AgAu alloy. By investigating the peroxide-like activity using TMB oxidation as a model transformation, we have found an increase of 152 fold in activities for the NRs relative to conventional Au NPs. Based on the kinetics results, the NRs also showed the lowest K-m, indicating better interaction with the substrate and faster product formation. We also observed a linear relationship between the concentration of the product and oxTMB as a function of H2O2 concentration, which could be further applied for H2O2 sensing applications (colorimetric detection). These data suggest that the NRs enable the combined effect of an increased surface area relative to solid counterparts, the possibility of exposing highly active surface sites, and the exploitation of nanoconfinement effects due to the void regions between the core and shell components. These results provide important insights into the optimization of peroxidase-like performances beyond what can be achieved in conventional NPs and may inspire the development of better-performing artificial enzymes.
  • Lahelma, Mari; Oksanen, Lotta; Rantanen, Noora; Sinkkonen, Saku; Aarnisalo, Antti; Geneid, Ahmed; Sanmark, Enni (2022)
    Objective To assess whether aerosol generation occurs during otologic surgery, to define which instruments are aerosol generating, and to identify factors that enhance safety in protection against airborne pathogens, such as severe acute respiratory syndrome coronavirus 2. Study Design An observational prospective study on aerosol measurements during otologic operations recorded between August and December 2020. Setting Aerosol generation was measured with an Optical Particle Sizer as part of otologic operations with anesthesia. Particles with a size range of 0.3 to 10 mu m were quantified. Aerosol generation was measured during otologic operations to analyze aerosols during drilling in transcanal and transmastoid operations and when using the following instruments: bipolar electrocautery, laser, suction, and cold instruments. Coughing is known to produce significant concentration of aerosols and is commonly used as a reference for high-risk aerosol generation. Thus, the operating room background concentration and coughing were chosen as reference values. Patients Thirteen otologic operations were included. The average drilling time per surgery was 27.00 minutes (range, 2.00-71.80 min). Intervention Different rotation speeds during drilling and other instruments were used. Main Outcome Measures Aerosol concentrations during operations were recorded and compared with background and cough aerosol concentrations. Results Total aerosol concentrations during drilling were significantly higher than background (p < 0.0001, d = 2.02) or coughing (p < 0.0001, d = 0.50). A higher drilling rotation speed was associated with higher particle concentration (p = 0.037, eta(2) = 0.01). Aerosol generation during bipolar electrocautery, drilling, and laser was significantly higher than with cold instruments or suction (p < 0.0001, eta(2) = 0.04). Conclusion High aerosol generation is observed during otologic surgery when drill, laser, or bipolar electrocautery is used. Aerosol generation can be reduced by using cold instruments instead of electric and keeping the suction on during aerosol-generating procedures. If drilling is required, lower rotation speeds are recommended. These measures may help reduce the spread of airborne pathogens during otologic surgery.
  • Maragkidou, Androniki; Jaghbeir, Omar; Hämeri, Kaarle; Hussein, Tareq (2018)
    In this study, we measured the concentrations of accumulation and coarse particles inside an educational workshop (March 31–April 6, 2015), calculated particle emission and losses rates, and estimated inhaled deposited dose. We used an Optical Particle Sizer (TSI OPS 3330) that measures the particle number size distribution (diameter 0.3–10 μm) and we converted that into particle mass size distribution (assuming spherical particles and unit density). We focused on two particle size fractions: 0.3–1 μm (referred as PN0.3−1 and PM0.3−1) and 1–10 μm (referred as PN1−10 and PM1−10). The occupants' activities included coffee brewing, lecturing, tobacco smoking, welding, scrubbing, and sorting/drilling iron. The highest concentrations were observed during welding with PN0.3−1 (PM0.3−1) was ∼1866 cm−3 (55 μg/m3) and PN1−10 (PM1−10) was ∼7 cm−3 (103 μg/m3). The lowest concentrations were observed during coffee brewing and metal turning with PN0.3−1 (PM0.3−1) was ∼22 cm−3 (0.7 μg/m3) and PN1−10 (PM1−10) was ∼0.5 cm−3 (4 μg/m3). The emissions rate of coarse particles was 85–1010 particles/hour × cm3 whereas that for submicron particle in the diameter range 0.3–1 μm was 5.7 × 104–9.3 × 104 particles/hour × cm3 depending on the activity and the ventilation rate. The coarse particles losses rate was 0.35–2.1 h−1 and the ventilation rate was 0.24–2.1 h−1. The alveolar received the majority and particles below 1 μm with a fraction of about 53% of the total inhaled deposited dose whereas the head/throat region received about 18%. This study is important for better understanding the health effects at educational workshops.
  • Hu, Man; Lehtonen, Aleksi; Minunno, Francesco; Mäkelä, Annikki (2020)
    Tree structure equations derived from pipe model theory (PMT) are well-suited to estimate biomass allocation in Scots pine (Pinus sylvestrisL.) and Norway spruce (Picea abies[L.] Karst.). However, age dependence of parameters should be accounted for when applying the equations.
  • Laursen, Karsten; Moller, Anders Pape; Haugaard, Lars; Öst, Markus; Vainio, Jouni (2019)
    Capital breeders, such as the eider duck Somateria mollissima, accumulate resources before the start of breeding. Eiders preferentially feed on blue mussels Mytilus edulis to build up body condition during winter. We explored how body condition and gizzard mass of wintering eiders relate to mussel quality and quantity, winter climate and body condition of females at the breeding grounds. Body condition during winter (defined as scaled body mass index) of eiders increased during winter and the magnitude of the effect depended on age and mussel quality. Gizzard mass of eiders increased during winter with effects of mussel quality, mussel stocks and sex. Body condition in winter of adult females increased from the first half of January to the second half of February on average by 1.5%, equal to c. 96 g. During the same period gizzard mass of adult females increased by 12.2%, i.e., a nearly ten-fold increase compared to that observed in body condition in winter. Body condition of females at the breeding grounds in Finland (defined as body condition at hatching) was significantly positively correlated with gizzard mass in winter, but not significantly correlated with body condition in winter. Thus, eiders allocate body reserves to increase gizzard mass but less so to increase body condition in winter. This can be considered an adaptive migratory strategy of these eiders, whereby large winter (pre-migratory) gizzards increase food processing capacity, making it possible for eiders to arrive at the breeding grounds with superior body condition and a high reproductive potential.
  • Villnäs, Anna; Mäkelin, Saara Elisa Iines; Vanni, Michael (2022)
    Benthic consumers profoundly impact nutrient regeneration in coastal marine ecosystems. The concurrent nutrient imbalance and warming of our coastal seas will change the nutritional requirements and metabolic demands of these consumers, which may affect their ability to recycle nitrogen and phosphorous. Here we explore whether nutrient excretion rates of two benthic consumers, the Baltic clam (Macoma balthica) and the invasive spionid polychaete (Marenzelleria spp.) can be quantified with basic biological traits across seasons using allometric and stoichiometric relationships. We found species-specific N and P excretion rates that positively link to allometric traits, i.e., per individual rates increased with body mass and temperature; thus, high mass-specific excretion rates characterized small relative to large macrofaunal individuals. Interestingly, our body size scaling coefficients diverge from predictions by the metabolic theory of ecology (MTE) and the universal model of excretion. Furthermore, stoichiometric traits and stable isotope signatures (delta C-13 and delta N-15) explained a minor additional proportion of variability in excretion rates among species. The excretion rates also varied strongly seasonally, with the highest nutrient recycling rates during summer months, when community NH4-N and PO4-P excretion clearly exceeded net sediment efflux. The seasonal pattern emphasized that changes in temperature and food availability drove metabolic processes and thus excretion rates of the benthic consumers, and indicated that these effects could outweigh the importance of animal biomass. Our results highlight the benefits of using allometric and stoichiometric traits when quantifying species-specific contributions to nutrient recycling in coastal marine environments, and in predicting alteration of function in response to environmental change.
  • Spadaro, Maria Chiara; Zhao, Junlei; Terry, William D.; Liu, Jian; Yin, Feng; Djurabekova, Flyura; Palmer, Richard E. (2019)
    The matrix assembly cluster source (MACS) represents a bridge between conventional instruments for cluster beam deposition (CBD) and the level of industrial production. The method is based on Ar+ ion sputtering of a pre-condensed Ar-M matrix (where M, is typically a metal such as Ag). Each Ar+ ion produces a collision cascade and thus the formation of metal clusters is in the matrix, which are then sputtered out. Here we present an experimental and computational investigation of the cluster emission process, specifically its dependence on the Ar+ ion angle of incidence and the cluster emission angle. We find the incidence angle strongly influences the emerging cluster flux, which is assigned to the spatial location of the deposited primary ion energy relative to the cluster into the matrix. We also found an approximately constant angle between the incident ion beam and the peak in the emitted cluster distribution, with value between 99 degrees and 109 degrees.
  • Luoma, Ville; Saarinen, Ninni; Wulder, Michael A.; White, Joanne C.; Vastaranta, Mikko; Holopainen, Markus; Hyyppä, Juha (2017)
    Forest resource information has a hierarchical structure: individual tree attributes are summed at the plot level and then in turn, plot-level estimates are used to derive stand or large-area estimates of forest resources. Due to this hierarchy, it is imperative that individual tree attributes are measured with accuracy and precision. With the widespread use of different measurement tools, it is also important to understand the expected degree of precision associated with these measurements. The most prevalent tree attributes measured in the field are tree species, stem diameter-at-breast-height (dbh), and tree height. For dbh and height, the most commonly used measuring devices are calipers and clinometers, respectively. The aim of our study was to characterize the precision of individual tree dbh and height measurements in boreal forest conditions when using calipers and clinometers. The data consisted of 319 sample trees at a study area in Evo, southern Finland. The sample trees were measured independently by four trained mensurationists. The standard deviation in tree dbh and height measurements was 0.3 cm (1.5%) and 0.5 m (2.9%), respectively. Precision was also assessed by tree species and tree size classes; however, there were no statistically significant differences between the mensurationists for dbh or height measurements. Our study offers insights into the expected precision of tree dbh and height as measured with the most commonly used devices. These results are important when using sample plot data in forest inventory applications, especially now, at a time when new tree attribute measurement techniques based on remote sensing are being developed and compared to the conventional caliper and clinometer measurements.
  • Leinonen, Jaakko T.; Surakka, Ida; Havulinna, Aki S.; Kettunen, Johannes; Luoto, Riitta; Salomaa, Veikko; Widen, Elisabeth (2012)
  • Pauklin, Priit; Eha, Jaan; Tootsi, Kaspar; Kolk, Rein; Paju, Rain; Kals, Mart; Kampus, Priit (2021)
    Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and beta blockers (BBs) are the drugs of choice for rate or rhythm control in these patients. The purpose of this study was to describe differences in arterial stiffness (AS), central blood pressure (cBP), and the role of BBs on cBP in patients with AF compared to healthy individuals. The authors included 76 patients with paroxysmal/persistent AF. Carotid-femoral pulse wave velocity (PWV) and cBP were measured and compared with data from 75 healthy individuals. Patients with AF had higher PWV (8.0 m/s vs. 7.2 m/s, p < .001), central systolic blood pressure (cSBP) (118 mm Hg vs. 114 mm Hg, p = .033), central pulse pressure (cPP) (39 mm Hg vs. 37 mm Hg, p = .035) and lower pulse pressure amplification (PPA) (1.24 vs. 1.30, p = .015), without differences in peripheral blood pressure (pBP) and heart rate (HR). AF patients had significantly increased PWV (beta= 0.500, p = .010, adjusted R-2 = 0.37) after adjustment for confounding factors. The use of BBs significantly reduced PPA (beta = -0.059, p = .017, adjusted R-2 = 0.30). AF patients have higher PWV, cSBP, cPP, and lower PPA, compared to healthy patients. These findings support the role of AS in the development of AF. Use of BBs is related to a potential adverse effect on cBP.
  • Bimbo, Luis M.; Sarparanta, Mirkka; Santos, Helder A.; Airaksinen, Anu J.; Makila, Ermei; Laaksonen, Timo; Peltonen, Leena; Lehto, Vesa-Pekka; Hirvonen, Jouni; Salonen, Jarno (AMERICAN CHEMICAL SOCIETY., 2010)
  • Bimbo, Luis M.; Sarparanta, Mirkka; Santos, Hélder A.; Airaksinen, Anu J.; Mäkilä, Ermei; Laaksonen, Timo; Peltonen, Leena; Lehto, Vesa-Pekka; Hirvonen, Jouni; Salonen, Jarno (AMERICAN CHEMICAL SOCIETY., 2010)
  • Pfeifer, Marion; Lefebvre, Veronique; Gardner, Toby A.; Arroyo-Rodriguez, Victor; Baeten, Lander; Banks-Leite, Cristina; Barlow, Jos; Betts, Matthew G.; Brunet, Joerg; Cerezo, Alexis; Cisneros, Laura M.; Collard, Stuart; D'Cruze, Neil; da Silva Motta, Catarina; Duguay, Stephanie; Eggermont, Hilde; Eigenbrod, Felix; Hadley, Adam S.; Hanson, Thor R.; Hawes, Joseph E.; Scalley, Tamara Heartsill; Klingbeil, Brian T.; Kolb, Annette; Kormann, Urs; Kumar, Sunil; Lachat, Thibault; Lakeman Fraser, Poppy; Lantschner, Victoria; Laurance, William F.; Leal, Inara R.; Lens, Luc; Marsh, Charles J.; Medina-Rangel, Guido F.; Melles, Stephanie; Mezger, Dirk; Oldekop, Johan A.; Overal, William L.; Owen, Charlotte; Peres, Carlos A.; Phalan, Ben; Pidgeon, Anna M.; Pilia, Oriana; Possingham, Hugh P.; Possingham, Max L.; Raheem, Dinarzarde C.; Ribeiro, Danilo B.; Ribeiro Neto, Jose D.; Robinson, W. Douglas; Robinson, Richard; Rytwinski, Trina; Scherber, Christoph; Slade, Eleanor M.; Somarriba, Eduardo; Stouffer, Philip C.; Struebig, Matthew J.; Tylianakis, Jason M.; Tscharntke, Teja; Tyre, Andrew J.; Urbina Cardona, Jose N.; Vasconcelos, Heraldo L.; Wearn, Oliver; Wells, Konstans; Willig, Michael R.; Wood, Eric; Young, Richard P.; Bradley, Andrew V.; Ewers, Robert M. (2014)
  • Näkki, Pinja; Setälä, Outi; Lehtiniemi, Maiju (2017)
    Microplastics (MPs) are observed to be present on the seafloor ranging from coastal areas to deep seas. Because bioturbation alters the distribution of natural particles on inhabited soft bottoms, a mesocosm experiment with common benthic invertebrates was conducted to study their effect on the distribution of secondary MPs (different-sized pieces of fishing line <1 mm). During the study period of three weeks, the benthic community increased MP concentration in the depth of 1.7-5.1 cm in the sediment. The experiment revealed a clear vertical gradient in MP distribution with their abundance being highest in the uppermost parts of the sediment and decreasing with depth. The Baltic clam Macoma balthica was the only study animal that ingested MPs. This study highlights the need to further examine the vertical distribution of MPs in natural sediments to reliably assess their abundance on the seafloor as well as their potential impacts on benthic communities.