Thraustochytrids as novel parasitic protists of marine free-living flatworms: <Emphasis Type="Italic">Thraustochytrium caudivorum</Emphasis> sp. nov. parasitizes <Emphasis Type="Italic">Macrostomum lignano</Emphasis>

The Labyrinthulomycota are a relatively poorly studied group of heterotrophic unicellular eukaryotes. They comprise three lineages, labyrinthulids, thraustochytrids, and aplanochytrids, which are all primarily marine organisms and considered to be important components of marine microbial communities. Recently a number of Labyrinthulomycota have been implicated as parasites of marine (but also terrestrial) plants and marine molluscs. Here we describe a new species of thraustochytrid, Thraustochytrium caudivorum sp. nov. that we have isolated from laboratory cultures of Macrostomum lignano (Rhabditophora, Macrostomorpha), a marine free-living flatworm. In these worms T. caudivorum can cause lesions, which start at the tip of the tail plate and which can lead to the dissolution of the posterior part of the animal. Although the worms can frequently cure these lesions and regenerate the lost parts, the lesions can also result in the complete dissolution of the animal. We describe this thraustochytrid based on pure agar cultures and infestations in the worm cultures. Moreover, we describe its pathological effects on the worms and its morphology using both light and electron microscopy. In addition, we report a phylogenetic analysis using a partial 18S rDNA sequence that allows us to place this new species within the thraustochytrids. Finally, we outline a protocol that allows to permanently remove the parasites from infested worm cultures. We conclude that thraustochytrids represent a novel group of parasites of free-living flatworms. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Mapping ecosystem services potential in Lithuania

This research presents a geographic information systems (GIS)-based method for ecosystem services (ES) potential assessment in a case study for the Lithuanian national territory. The ES potential was assessed for 31 CORINE land-cover classes (CLC2006) together with 31 ES categorized into regulating, provisioning and cultural ES. An expert-based ranking approach using a two-dimensional ES matrix and a geospatial analysis was applied to determine total ES potential, spatial patterns and relations among multiple ES. Results showed that forest areas had the highest potential for ES delivery whereas ES potential in urban areas was lowest. The spatial autocorrelation of regulating and cultural ES were dispersed while provisioning ES were significantly clustered. The principal component analysis (PCA) identified five factors with distinctive geospatial distribution: Factor 1 – forest areas, Factor 2 – aquatic environments, Factor 3 – livestock farming and energy production, Factor 4 – agricultural food production and Factor 5 – mineral extraction sites. The plotting of Factors 1 and 2 accounted for 72.81% of variance and identified three ES bundles composed by specific ES types: Bundle 1 – forest ecosystems, Bundle 2 – marine and freshwater ecosystems and Bundle 3 – mixed provisioning ecosystems. Trade-offs occur between regulating and cultural ES against the provisioning ES crop production and livestock farming. We conclude that the presented ES assessment can support decision-makers in the development of strategies for natural resources management at national and regional level, support the identification of trade-offs and synergies among ES types and foster ES research in Lithuania.