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At the Pingorsuit Glacier in North‐West Greenland, an organic‐rich deposit that had recently emerged from the retreating ice cap was discovered at an elevation of 480 m above sea level. This paper reports on macrofossil analyses of a coarse detritus gyttja and peaty soil, which occurred beneath a thin cover of till and glacifluvial deposits. The sediments contained remains of vascular plants, mosses, beetles, caddisflies, midges, bryozoans, sponges and other invertebrates. The flora includes black spruce, tree birch, boreal shrubs and wetland and aquatic taxa, which shows that mires, lakes and ponds were present in the area. We describe a new extinct waterwort species Elatine odgaardii. The fossils were deposited in a boreal environment with a mean July air temperature that was at least 9 °C higher than at present. The fossil assemblages show strong similarities with others from Greenland that have been assigned an Early Pleistocene age, and we suggest a similar age for the sediments found at the margin of the Pingorsuit Glacier. At the Pingorsuit Glacier in North‐West Greenland, an organic‐rich deposit was discovered at an elevation of 480 m above sea level. The sediments contained remains of vascular plants, mosses, beetles, caddisflies, midges, bryozoans, sponges and other invertebrates. The fossils were deposited in a boreal environment with a mean July air temperature that was at least 9 °C higher than at present. [ABSTRACT FROM AUTHOR]

Effects of insecticides on terrestrial adult life stages of otherwise aquatic insects, such as mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera), are largely unknown. In the present study, a risk model was used to pinpoint the species most likely to experience effects due to spray drift exposure during the adult life stage. Using data from an earlier case study with lambda‐cyhalothrin, 6 species with different life cycle traits were used to explore how life cycle characteristics may influence vulnerability. In addition, we performed a generic calculation of the potential effect on the terrestrial life stages of 53 species (including 47 species with unknown sensitivity). Our approach incorporated temporal and spatial distribution of both the insect and the insecticide, creating different exposure conditions among species due to variation in the relative proportion of the populations present at the time of insecticide spraying. The Ephemeroptera species represented were least vulnerable due to their extremely short adult life span and relatively short flight period. Based on their life cycle characteristics, Plecoptera and Trichoptera species were more vulnerable. These vulnerable species segregated into 2 distinct groups; one with a long adult life span to emergent period ratio and another with a high overlap between emergent period and spraying season. We therefore recommend that future ecotoxicological tests be done on species with these life cycle characteristics. Environ Toxicol Chem 2021;40:1778–1787. © 2021 SETAC [ABSTRACT FROM AUTHOR]

Lateglacial submarine lake sediments are reported for the first time from the Kattegat Sea in southern Scandinavia. The Lateglacial sediments were collected from a vibrocore that contained, from top to bottom, Holocene marine muddy sand, Holocene brackish‐water mud, Early Holocene peat with remains of Betula pubescens and telmatic plants, Lateglacial lake deposits that are the focus of this paper, and homogenous sand. Radiocarbon dating of terrestrial plant remains from the Lateglacial sediments gave ages between 12 400 and 12 800 cal a bp, corresponding to the Younger Dryas. The Lateglacial sediments contain remains of Betula nana and other plants indicating a tundra‐like open landscape with dwarf shrub heaths, which is typical for the region. Remains of macrolimnophytes indicate shallow carbonate‐rich, cool lake waters. Remains of larvae of Trichoptera and Chironomidae dominate the invertebrate fauna and indicate a fairly species‐rich fauna. Half of the trichopteran taxa today have their distribution north of Denmark or show a generally northern distribution in Europe. The lake sediments are found at ∼ 24 m below sea level, and the presence of lake sediments shows that this part of Kattegat had not been transgressed by the sea during the Younger Dryas. [ABSTRACT FROM AUTHOR]

Abstract: Insecticides are important drivers of biodiversity loss and ecological impairment in freshwater ecosystems. Freshwater insects may be exposed to insecticides via water during larval/nymph stages and via air, habitats, and food during adult stages in the terrestrial environment. The aquatic risk assessment (RA) of pesticides does not consider terrestrial life stages, and a literature review revealed that pesticide ecotoxicity data for adult freshwater insects are very scarce and outdated. Consequently, it is not possible to assess how adult freshwater insects may be protected through RA programs for terrestrial non‐target organisms. We give guidance to generating and using of such ecotoxicity data focusing on species selection, test design and type of ecotoxicity information. Policy implications. This commentary considers how terrestrial stages of aquatic insects are protected by pesticide risk assessment (RA) and highlights the necessity of performing holistic risk assessment, focusing on organisms and populations as supplement to current subdivisions in element‐based compartments (e.g. aquatic and terrestrial ecosystems). [ABSTRACT FROM AUTHOR]

Studies of interglacial successions are critical to our understanding of the environmental history of an area. Analyses of macrofossil remains of plants and invertebrates from Eemian sediments exposed in a coastal cliff section at Borðoyarvík near Klaksvík, Bordoy, northeastern Faroe Islands, indicate that the sediments accumulated in a coastal lagoon. The fossil flora comprises tree birch Betula sect. Albae and we suggest that birch forests were found locally at sheltered sites in the area. Tree birch also occurred on the islands during the mid-Holocene. The only other woody plant recovered from the Eemian deposit is the dwarf-shrub Empetrum nigrum, which is common on the islands today. Remains of herbaceous plants are rare but include Viola, Ajuga, Myosotis, Urtica dioica and Ranunculus. The bryophyte flora is species-rich and most of the fragments belong either to stream species or to species of humid or wet habitats. The fossil flora and fauna also comprise a number of freshwater species that probably lived in an oligotrophic lake and in streams in the catchment of the lagoon. The climate during deposition of the lagoonal sediments was similar to the Holocene oceanic climate of the Faroe Islands. The study adds to our understanding of Eemian environments in the North Atlantic region and helps to fill a knowledge gap about the history of the flora and fauna of the Faroe Islands, which is of biogeographical importance. [ABSTRACT FROM AUTHOR]

Lowland stream ecosystems are subjected to multiple anthropogenic stressors, usually nutrient enrichment in combination with sedimentation of fine particles and low flow periods in summer. Here, we investigated the temporal development of the benthic algae community in response to these three stressors and linkages to the trait characteristics of the community to explore the mechanisms responsible for stress-induced community changes., We investigated the response of benthic algae species composition, traits (life forms, cell size categories), biovolume and chlorophyll a (Chl- a) concentration to low flow in combination with nutrient enrichment and fine sedimentation in twelve large outdoor stream flumes (12 m long) resembling small streams in size and habitat characteristics. The experiment consisted of two phases: a normal-flow phase followed by a low-flow phase (90% current velocity reduction), each spanning 4 weeks. We applied a eutrophication scenario (mean increases of 1.14-5.48 mg N/L and 0.01-0.06 mg P/L in the flumes for dissolved inorganic nitrogen and phosphate respectively) throughout the experiment. Under low flow, we supplemented this with a fine sedimentation scenario (>90% stream bed cover). We took samples once in the normal-flow phase and every week during the low-flow phase., We observed strong responses in the benthic algae community to sudden changes in low flow and fine sedimentation, mediating rapid species turnover with a decreased algal biovolume and increased abundance of large, motile species. However, we did not observe any pronounced responses to nutrient enrichment. In contrast to the observations for other variables, we found a continuous increase in Chl- a concentration during low flow. This was likely due to continuous fine sedimentation during this phase, reducing light availability which probably resulted in an increase of cell-level Chl- a concentration in response to light limitation and lower rates of light-induced Chl- a degradation., The rapid response of the benthic algal community to the applied stressors suggests that even short periods of major stressor exposure may significantly affect benthic algae in lowland systems. We suggest that short-term stress events may have cascading effects on several important ecosystem processes given the importance of benthic algae for the productivity of these systems. [ABSTRACT FROM AUTHOR]

The spatial organisation of biotic communities derives from factors operating at a wide range of spatial and temporal scales. Despite strong scientific evidence of prevalent spatial control of community composition in freshwater ecosystems, local environmental factors are often considered as the main drivers of community change. Furthermore, taxonomic approaches are most frequently used, and few studies have compared the relative importance of local and regional control of trait versus the taxonomic composition in stream ecosystems., Using a spatially dense data set covering all stream sizes in a lowland European region of c. 42 000 km2 and three organism groups (macrophytes, macroinvertebrates and fishes), we compared the relative importance of spatial and environmental determinants of species and trait composition in the study streams, classified into headwaters (stream order 1-2) and downstream sites (stream order >2)., We hypothesised that (i) there is a higher correspondence between environmental conditions and trait composition than with species composition, (ii) dispersal limitation (pure spatial structuring) is greater in headwaters than in downstream sites and (iii) dispersal limitation (pure spatial structuring) is weakest for macroinvertebrates, intermediate for macrophytes and strongest for fishes., The most consistent pattern across organisms and stream order groups was a higher correspondence between environmental variation and trait composition as well as a higher number of environmental variables significantly related to trait composition than with species composition (hypothesis 1). Spatial structuring peaked in headwater macrophyte communities and downstream fish communities (hypotheses 2 & 3) - a pattern that was amplified when separate analyses of traits describing species dispersal potential were undertaken., Our study highlights the potential of traits to capture multiple environmental changes in stream ecosystems and illustrates how organism-specific and highly context-dependent patterns in community organisation can emerge as a consequence of interactions between habitat connectivity (i.e. top versus lower parts of the stream network) and organism dispersal potential. [ABSTRACT FROM AUTHOR]

Analyses of a sediment core from the Great Belt documented the local presence of fluvial deposits. The sediments consisted of silt, clay, sand and organic detritus and they contained macroscopical remains of a mixture of terrestrial, telmatic, lacustrine and fluvial plants and animals. Most noteworthy was the abundance of remains of caddisfly larvae, totalling at least 24 species, which were dominated by fluvial species. Thus, filter-feeding hydropsychids made up approximately 95% out of 1496 identified specimens, the dominating species being Hydropsyche contubernalis and H. pellucidula. The present-day requirements of the recorded species point to a fairly fast-flowing river, at least locally, with areas of stones (some with moss growth) and gravel, but also to more slowly-flowing parts with sand, fine and coarse detritus. This river may have been considerably larger than any present-day Danish river. It appears that the fluvial deposits formed locally in connection with flooding of the area south of the core position. AMS radiocarbon dating shows that the sequence was deposited very rapidly during the early Holocene, about 10650 to 10250 cal. years BP. The occurrence of the lentic Leptocerus tineiformis points to a climate at least as warm as today. [ABSTRACT FROM AUTHOR]