AQUATIC MACROPHYTE COMMUNITIES OF THE WILDERNESS LAKES: COMMUNITY STRUCTURE AND ASSOCIATED ENVIRONMENTAL CONDITIONS

SUMMARY

The structure and summer biomass (g m^?2 dry mass) of the principal aquatic macrophyte communities of the Wilderness Lakes were measured. Both emergent and submerged communities were included in the study. Productivity estimates were made by multiplying biomass by production/biomass ratios for each species. Salinity gradients in the system are described and details of the different sediment types associated with the macrophytes are given. There was considerable variation in production rates between the different water bodies often coinciding with a salinity gradient. However, rapid, natural changes in the communities are described which also influence production rates in a given water body. Production rates (g dry mass m^?2 a^?1) were of the order: Typha latifolia > Phragmites australis > Scirpus littoralis > Potamogeton pectinatus > Chara qlobularis > Ruppia cirrhosa. The significance of the macrophyte rates is discussed in relation to Wilderness Lakes area as a whole.     

Features of the structure and spatial distribution of plankton in the Sheksna Reservoir

Based on the field studies conducted in August 2005 and 2007, the distributions of zooplankton structure and abundance, as well as chlorophyll content, in the Sheksna Reservoir are analyzed. A total of 107 zooplankton species have been found (46 Cladocera, 18 Copepoda, and 43 Rotifera), including 24 species (10 Cladocera, 2 Copepoda, and 12 Rotifera) new for the reservoir. In the surface layer of water, where blue-green algae concentrate, zooplankton abundance and biomass are 1.5–5 times lower and the zooplankton structure is simpler than in deeper layers. The highest zooplankton biomass (>3 g/m³) are observed in Lake Beloe and the upper area of the Sheksna section, while in the near-shore sites it did not exceed 1 g/m³. There are no significant changes in zooplankton abundance when compared to the abundance recorded at the end of the past century.     

Interannual fluctuations in copepod abundance and contribution of small forms in the Drake Passage during austral summer

The relative importance of small forms of copepods has been historically underestimated by the traditional use of 200?C300-??m mesh nets. This work quantified the distribution and abundance of copepods, considering two size fractions (<300???m and >300???m), in superficial waters (9?m deep) of the Drake Passage and contributed to the knowledge of their interannual fluctuations among three summers. Four types of nauplii and eleven species of copepods at copepodite and adult stages were identified, with abundance values of up to 13 ind L^?1 and 28,300???g C m^?3. The <300-??m fraction, composed of Oithona similis, small cyclopoids and nauplii, dominated the copepod communities in the 3?years; it accounted for more than 77% of the total number and for between 40 and 63% of the total biomass. Changes in density and biomass values among the three cruises differed according to copepod size fraction and water mass; the >300-??m fraction showed no changes among the 3?years, both in Antarctic (density and biomass) and in Subantarctic waters (density), whereas the <300-??m fraction showed higher (density and biomass) values in 2001 both in Subantarctic and in Antarctic waters. Sea surface temperature and its anomaly accounted for the largest proportion of variability in copepod density and biomass, particularly for the <300-??m fraction.     

Seasonal abundance and distribution of drift algae and seagrasses in the mid-Indian river lagoon,Florida

The distribution of seagrasses in a 15-ha area in the mid-Indian River lagoon on Florida's central east coast was mapped. Halodule wrightii Aschers. dominated in shallow (< 0.4 m) and Syringodium filiforme Kutz. in deeper water (> 0.5 m). Thalassia testudinum Banks ex König occurred as scattered patches. Areal coverage of monospecific stands of the three major seagrasses was: Syringodium 35%, Halodule 14%, Thalassia 6% and bare sand 21%. Mixed species stands, mostly Syringodium with Hallodule, covered 25% of the total study area. Above-ground seagrass biomass was maximum in summer (June–July) and minimum in late winter (February–March). Summer maxima ranged from 60 g dry wt. m^?2 for Syringodium to ～ 300 g dry wt. m^?2 for Thalassia, with Halodule intermediate at 160 g dry wt. m^?2.Because distribution of unattached benthic macroalgae (“drift algae”), primarily Gracilaria spp., was highly aggregated, aggregations were first mapped, followed by stratified quadrat sampling in order to estimate total drift algal abundance. In April 1982, high-density patches covering a few hectares averaged 409 g dry wt. m^?2. At maximum abundance, averaged over the entire 15-ha mapped area, drift algal biomass was 164 g dry wt. m^?2; mean above-ground seagrass biomass was only 49 g dry wt. m^?2. Other large expanses of the lagoon had similar accumulations of drift algae; densities of some accumulations exceeded 15 000 g dry wt. m^?2. Year-to-year variability of seagrass and drift algal abundance was high and may be related to variations in light levels.Drift algae harbor high densities of animals and at times may be quantitatively more important locally than seagrasses in terms of habitat, nutrient dynamics and primary production.     

Heterotrophic bacteria in epiphyton of higher aquatic plants in the Ivankovo Reservoir

Concentrations of heterotrophic bacteria have been measured in the epiphyton of seven species of higher aquatic plants in the Ivankovo Reservoir. The abundance and biomass of the bacterioepiphyton range from 64.1 × 10⁶ to 283.7 × 10⁶ cells/сm² and from 1.6 to 6.7 μg С/сm². Maximum values are recorded in the epiphyton of emergent aquatic plants.     

2011-2020年长江口大型底栖动物群落结构变化趋势

对2011—2020年夏季长江口48个站位的大型底栖动物定量监测数据进行统计分析,研究长江口海域底栖生物群落时空结构演变特征。结果表明,近10年长江口海域共鉴定大型底栖动物284种,其中多毛类128种,占总种数的45.1%,甲壳类64种占22.2%,软体动物56种占19.7%,棘皮动物16种占5.6%,其他类合计20种。平均生物密度为(79.5±45.9)个/m²(年份变幅14.7—195个/m²)。平均生物量为(5.20±3.25)g/m²(年份变幅1.01—10.11g/m²),多毛类、软体动物、甲壳类是生物密度和生物量组成的主要类群。十年期间种类数、生物密度和生物量均呈现明显上升趋势,口外区贡献最突出。四个监测区域(南支、北支、杭州湾、口外)的优势种差异大。丝异须虫Heteromastus filiformis在各年份的优势种中出现的频度显著最大。总体来看,长江口监测区域大型底栖动物群落自然演变趋势向好。三项多样性指数统计结果表明,口外区大型底栖动物种类组成多样性水平显著高于口内三个区。生物群...     

Mesozooplankton distribution in northern Svalbard waters in relation to hydrography

We investigated the distribution of mesozooplankton in waters north of Svalbard (north of 78°50′N) at 38 stations in August and September of 2002, 2003 and 2004. The zooplankton community was numerically dominated by copepods (58–98% of the total abundance). Zooplankton abundance ranged from 115 individuals m⁻³ at the northern most location to 12,296 individuals m⁻³ on the shelf. Cluster analysis revealed four different groups with distinct geographic integrity that were identified by variation in species densities rather than by variation in taxonomic composition. Water temperature and salinity differed significantly between the different cluster groups indicating that part of the observed variations in species distribution relate to differences in hydrography. Numerous significant regressions between zooplankton abundance at species level and hydrographical parameters suggest that variability in water masses has measurable effects on zooplankton distribution and species composition in the study area.     

Predicting the distribution of invasive crayfish (Pacifastacus leniusculus) in a Kusiro Moor marsh (Japan) using classification and regression trees

Summer distributions of the invasive signal crayfish (Pacifastacus leniusculus) were investigated in relation to physicochemistry in a Kusiro Moor marsh and its inflows and outflows in northern Japan. Maximum crayfish abundance and biomass were 1.04 individuals/m² and 3.56 g dry mass (DM)/m² in littoral marsh habitats, and 5.84 individuals/m² and 13.48 g DM/m² in stream habitats. Classification tree analysis was used to predict crayfish occurrence at 102 sites from all habitats (i.e. littoral marsh, pelagic marsh and stream) while regression tree analyses were used to predict crayfish abundance at littoral marsh and stream sites separately. The classification tree showed that crayfish occurrence was primarily determined by undercut bank volume regardless of habitat identity. When undercut bank volume was <0.0054 m³, crayfish were predicted to be absent at marsh sites, but expected to occur at stream sites where pH and water temperature exceeded 6.5 and 14.3°C, respectively. The regression tree using only littoral marsh sites showed that undercut bank volume, followed by dissolved oxygen level, determined the splits of the tree. Crayfish abundance was highest when undercut bank volume was >0.61 m³, and moderately high when dissolved oxygen was >9.09 mg/l and undercut bank volume was <0.61 m³. On the other hand, the regression tree using only stream sites showed that water temperature was the major predictor that determined the splits. We discuss the roles of physicochemical factors as limiting factors of the distribution pattern of the invasive crayfish.     

Linking aquatic and terrestrial food webs – Odonata in boreal systems

1. It is increasingly realised that aquatic and terrestrial systems are closely linked. We investigated stable isotope variations in Odonata species, putative prey and basal resources of aquatic and terrestrial systems of northern Mongolia during summer. 2. In permanent ponds, δ¹³C values of Odonata larvae were distinctly lower than those of putative prey, suggesting that body tissue comprised largely of carbon originating from isotopically light carbon sources. Presumably, prey consumed during autumn and winter when carbon is internally recycled and/or methanotrophic bacteria form an important basal resource of the food web. In contrast, in a temporary pond, δ¹³C values of Odonata larvae were similar to those of putative prey, indicating that their body carbon originated mainly from prey species present. 3. Changes in δ¹⁵N and δ¹³C values between larvae and adults were species specific and reflected differential replacement of the larval isotopic signature by the terrestrial diet of adult Odonata. The replacement was more pronounced in Odonata species of permanent ponds than in those of the temporary pond, where larvae hatched later in the year. Replacement of larval carbon varied between tissues, with wings representing the larval isotopic signature whereas thoracic muscles and eggs reflected the δ¹⁵N and δ¹³C values of the terrestrial diet of adults. 4. The results suggest that because of their long larval development, Odonata species of permanent ponds carry the larval signature, which is partly replaced during their terrestrial life. Terrestrial prey forms the basis for egg production and thus the next generation of aquatic larvae. In temporary ponds, in contrast, Odonata species rely on prey from a single season, engage in a prolonged aquatic phase and hatch later, leaving less time to acquire terrestrial prey resources for offspring production. Stable isotope analysis provided important insights into the food webs of the waterbodies and their relationship to the terrestrial system.     

Distribution and production ofChironomus salinarius (Diptera: Chironomidae) in a shallow coastal lagoon in the Bay of Cádiz

The abundance, generation time and production ofChironomus salinarius larvae in a lagoon fish-pond system in the Bay of Cádiz were studied by taking monthly samples at 3 sites during 1991 and 1992. Numerical abundance and biomass of larvae showed considerable spatial, seasonal and interannual variation (ANCOVAs,P<0.001). The maximum mean annual density was 7048 larvae m^–2, and corresponded to a biomass of 3.08 g dry weight (DW) m^–2. It was recorded at the site with the lowest rate of water renewal. Seasonal patterns were similar at all sites, with main annual peaks of abundance and biomass in autumn-early winter. Chironomid density was positively related to the biomass of benthic macroalgae (P<0.001). The population studied was multivoltine with a probable average of five generations per year, with overlapping cohorts and a predominance of third- and fourth-instar larvae. Estimates of annual production ranged between 72.2 g DW m^–2 yr^–1 at the site with the lowest rate of water renewal in 1991 and 0.1 g DW m^–2 yr^–1 at the site with the highest rate of water renewal in 1992. Mean annual production and the production/biomass ratio for the system was estimated to be 16.8 g DW m^–2 yr^–1 and 12.7, respectively. Possible factors leading to the observed density fluctuations are discussed, as well as possible sources of error in production estimates.     

Feeding habitats of blue sheep (Pseudois nayaur) during winter and spring in Helan Mountains, China

The feeding habitat selection of blue sheep (Pseudois nayaur) was studied by direct observation method in the Helan Mountains, China during winter (from November to December) and spring (from April to June) from 2003 to 2004. We established 25 line transects to collect information on feeding habitats used by blue sheep. Blue sheep in the study area preferred mountain savanna forests, a habitat dominated by Ulmus glaucescens, with medium tree density (<4 individuals / 400 m²), moderate tree height (4–6 m), higher shrub density (> 5 individuals / 100 m²), higher shrub (> 1.3 m), higher food abundance (> 50 g), moderate distance to human disturbance (< 500 m), and mild distance to bare rock (< 2 m). Such habitats characterized by 12 ecological factors were preferred as feeding areas by blue sheep during winter. Similar to habitat selection by the species during winter, blue sheep also showed a preference for mountain savanna with tree dominated by Ulmus glaucescens and medium tree density (< 4 individuals / 400 m²) during spring. Nevertheless, blue sheep preferred medium tree height (< 6 m), moderate tree density (5–10 individuals / 100 m²), medium shrub height (1.3–1.7 m), higher food abundance (> 100 g), moderate altitude (< 2 000 m), moderate distance to water resource (< 500 m), and medium hiding cover (50%–75%) during spring. Selection of the feeding habitats by sheep showed a significant difference in vegetation type, landform feature, dominant tree, tree height, shrub density, distance to the nearest shrub, food abundance, slope direction, slope degree, distance to water resource, and hiding cover between winter and spring. Results of principal components analysis indicated that the first principal component accounted for 24.493% of the total variance among feeding habitat variance during winter, with higher loadings for vegetation type, dominant tree, tree height, distance to the nearest tree, shrub density, shrub height, altitude, distance to water resource, and distance to human disturbance. In spring, the first principal components explained 28.777% of the variance, with higher loadings for vegetation type, distance to the nearest tree, shrub height, distance to the nearest shrub, food abundance, altitude, and distance to human disturbance. Translated from Zoological Research, 2005, 26(6): 580–589 [译自: 动物学研究]     

Substance and energy flows formed by the emergence of amphibiotic insects across the water–air boundary on the floodplain lakes of the Volga River

Substance flow across the water–air boundary on the floodplain Lake Holodnoe (Saratov oblast) is generally formed by the Culicomorpha (76.1%) and accounts for 0.35 g/m² of the lake area per year. The energy flow amounts to 1.87 kcal/m², and most of it accounts for the second half of summer and autumn. Annual removal of biogenic elements is 0.18 g/m² for carbon, 0.04 g/m² for nitrogen, and 0.004 g/m² for phosphorus. The greatest contribution to flows of substance and energy is brought by large species of chironomids, as well as chaoborids and medium-sized chironomids, which produce several generations within a year and reach high abundance at a larval stage. Other floodplain lakes of the Volga River with similar biotopical features and species composition of amphibiotic insects are characterized by a quantitatively similar level of exchange processes with adjacent land ecosystems across the water–air boundary.     

Response of understory vegetation to variable tree mortality following a mountain pine beetle epidemic in lodgepole pine stands in northern Utah

We analyzed the long-term dynamics of aboveground biomass ofLeymus chinense steppe in relation to interannual variation of precipitation and temperature during 1980–1989 at levels of community, growth form and species in the Xilin river basin, Inner Mongolia Autonomous Region, China. Annual aboveground net primary production (ANPP) varied from 154.00 g m^-2 yr^-1 in 1980 to 318.59 g m^-2 yr^-1 in 1988, with a mean of 248.63 g m^-2 yr^-1 and the coefficient of variation of 25%. ANPP was not significantly correlated to annual precipitation and total precipitation during April–September atp0.05 level, but precipitation in May and August accounted for 69% of interannual variation of ANPP. The means of rain use efficiency and water use efficiency ofL. chinense steppe were 8.1 kg DM ha^-1 mm^-1 yr^-1 and 0.89 mg DM g^-1 H₂O respectively. Aboveground biomass of various growth forms and species had different response patterns to interannual variation of precipitation and temperature. Monthly and seasonal distribution of precipitation and temperature were the key controls of aboveground biomass of species.     

Zooplankton of Lake Kandrykul (Republic of Bashkortostan,Russia) under Conditions of Anthropogenic Eutrophication

The species diversity, abundance, and biomass of zooplankton in the pelagic and coastal zones of Lake Kandrykul were studied in 2007–2012. The community was dominated by large Cladocera. The maximum abundance of zooplankton was observed in the anomalously warm 2010. In July, the highest abundance of zooplankton (1300 thousand ind./m³) was recorded near the southern coast in stands of mare′s-tail Hippurus vulgaris; that of biomass (9 g/m³) was found near the northern shore in stands of narrow-leaved cattail Typha angustifolia. The lowest values of the number and biomass of aquatic invertebrates were observed in the pelagial (32 thousand ind./m³ and 0.1 g/m³) and along the M5 motorway stretching aside the northeastern coast (188 thousand ind./m³ and 0.5 g/m³). The Shannon index value (1.3–2.1) corresponded to the meso-eutrophic type of water bodies. In 2007, according to the Mjaemets trophicity index (E), the lake ecosystem was oligotrophic (E 0.11); in 2010–2012 it was mesotrophic (in the pelagial, E value was 0.54; in the open littoral it was 0.76) or weakly eutrophic (E values of protected littoral were 1.52). The estimates of water trophy as assessed by zooplankton are close to those assessed by the number and biomass of phytoplankton (meso-eutrophic type). The rapid eutrophication of the lake ecosystem was revealed. In 6 years the trophic status of the lake changed from oligo-mesotrophic to meso-eutrophic.     

Short-range spatial variability of soil δ15N natural abundance – effects on symbiotic N2-fixation estimates in pea

The δ¹⁵N natural abundance (‰) of the total soil N pool varies at the landscape level, but knowledge on short-range variability and consequences for the reliability of isotopic methods are poorly understood. The short-range spatial variability of soil δ¹⁵N natural abundance as revealed by the ¹⁵N abundance in spring barley and N₂-fixing pea was measured within the 0.15–4 m scale at flowering and at maturity. The short-range spatial variability of soil δ¹⁵N natural abundance and symbiotic nitrogen fixation were high at both growth stages. Along a 4-m row, the δ¹⁵N natural abundance in barley reference plants varied up to 3.9‰, and sometimes this variability was observed even between plants grown only 30 cm apart. The δ¹⁵N natural abundance in pea varied up to 1.4‰ within the 4-m row. The estimated percentage of nitrogen derived from the atmosphere (%Ndfa) varied from 73–89% at flowering and from 57–95% at maturity. When increasing the sampling area from 0.01 m² (single plants) and up to 0.6 m² (14 plants) the %Ndfa coefficient of variation (CV) declined from 5 to 2% at flowering and from 12 to 2% at maturity. The implications of the short-range variability in δ¹⁵N natural-abundance are that estimates of symbiotic N₂-fixation can be obtained from the natural abundance method if at least half a square meter of crop and reference plants is sampled for the isotopic analysis. In fields with small amounts of representative reference crops (weeds) it might be necessary to sow in reference crop species to secure satisfying N₂-fixation estimates.     

Abiotic and biotic factors affecting zooperiphyton development in a waterflow of a cooling water pool

The study is concerned with invertebrates populating riffle stones in a cooling water pool. It was shown that the invertebrate community is dominated by Oligochaeta of the genus Naididae in abundance, and Plumatella emarginata bryozoans, in biomass. The study revealed the following: (1) in communities with biomass >100 g/m² abundance and biomass are affected by roughness and lightness of the substrate; (2) bryozoan biomass and Oligochaeta abundance correlate.     

Habitat engineering by the invasive zebra mussel <Emphasis Type="Italic">Dreissena polymorpha</Emphasis> (Pallas) in a boreal coastal lagoon: impact on biodiversity

Habitat engineering role of the invasive zebra mussel Dreissena polymorpha (Pallas) was studied in the Curonian lagoon, a shallow water body in the SE Baltic. Impacts of live zebra mussel clumps and its shell deposits on benthic biodiversity were differentiated and referred to unmodified (bare) sediments. Zebra mussel bed was distinguished from other habitat types by higher benthic invertebrate biomass, abundance, and species richness. The impact of live mussels on biodiversity was more pronounced than the effect of shell deposits. The structure of macrofaunal community in the habitats with >10³ g/m² of shell deposits devoid of live mussels was similar to that found within the zebra mussel bed. There was a continuous shift in species composition and abundance along the gradient ‘bare sediments—shell deposits—zebra mussel bed’. The engineering impact of zebra mussel on the benthic community became apparent both in individual patches and landscape-level analyses.     

Abiotic drivers of interannual phytoplankton variability and a 1999–2000 regime shift in the North Sea examined by multivariate statistics

The Dutch coastal zone is a region of the North Sea with a marked interannual and long‐term abiotic and phytoplankton variability. To investigate the relationship between abiotic variability and phytoplankton composition, two routine water monitoring data sets (1991–2005) were examined. Multivariate statistics revealed two significant partitions in the data. The first consisted of interannual abiotic fluctuations that were correlated to Rhine discharge that affected the abundance of summer and autumn diatom species. The second partition was caused by a shift in the abiotic data from 1998 to 1999 that was followed by a shift in phytoplankton composition from 1999 to 2000. Important factors in the abiotic shift were decreases in suspended matter (SPM) and phosphate (DIP) concentrations, as well as in pH. The decrease in SPM was caused by a reduction in wind speed. The increase in water column daily irradiance from the decrease in SPM led to increases in the abundance of winter–spring species, notably the prymnesiophyte Phaeocystis globosa. Because wind speed is related to the North Atlantic Oscillation (NAO) index it was possible to correlate NAO index and P. globosa abundance. Only five abiotic variables representing interannual and long‐term variability, including Rhine discharge and NAO index, were needed to model the observed partitions in phytoplankton composition. It was concluded that interannual variability in the coastal phytoplankton composition was related to year‐to‐year changes in river discharge while the long‐term shift was caused by an alternating large‐scale meteorological phenomenon.     

Sediment deposition from eroding peatlands alters headwater invertebrate biodiversity

Land use and climate change are driving widespread modifications to the biodiverse and functionally unique headwaters of rivers. In temperate and boreal regions, many headwaters drain peatlands where land management and climate change can cause significant soil erosion and peat deposition in rivers. However, effects of peat deposition in river ecosystems remain poorly understood. We provide two lines of evidence—derived from sediment deposition gradients in experimental mesocosms (0–7.5 g/m²) and headwaters (0.82–9.67 g/m²)—for the adverse impact of peat deposition on invertebrate community biodiversity. We found a consistent negative effect of sediment deposition across both the experiment and survey; at the community level, decreases in density (1956 to 56 individuals per m² in headwaters; mean 823 ± 129 (SE) to 288 ± 115 individuals per m² in mesocosms) and richness (mean 12 ± 1 to 6 ± 2 taxa in mesocosms) were observed. Sedimentation increased beta diversity amongst experimental replicates and headwaters, reflecting increasing stochasticity amongst tolerant groups in sedimented habitats. With increasing sedimentation, the density of the most common species, Leuctra inermis, declined from 290 ± 60 to 70 ± 30 individuals/m² on average in mesocosms and >800 individuals/m² to 0 in the field survey. Traits analysis of mesocosm assemblages suggested biodiversity loss was driven by decreasing abundance of invertebrates with trait combinations sensitive to sedimentation (longer life cycles, active aquatic dispersal of larvae, fixed aquatic eggs, shredding feeding habit). Functional diversity metrics reinforced the idea of more stochastic community assembly under higher sedimentation rates. While mesocosm assemblages showed some compositional differences to surveyed headwaters, ecological responses were consistent across these spatial scales. Our results suggest short‐term, small‐scale stressor experiments can inform understanding of “real‐world” peatland river ecosystems. As climate change and land‐use change are expected to enhance peatland erosion, significant alterations to invertebrate biodiversity can be expected where these eroded soils are deposited in rivers.     

Zoobenthos of the Cheshskaya Bay (southeastern Barents Sea): spatial distribution and community structure in relation to environmental factors

Structural and functional characteristics of zoobenthos of the Cheshskaya Bay (SE Barents Sea) were studied at 21 stations in June/July 1995. Strong prevailing cyclonic and tidal currents result in relatively uniform temperature and salinity in the area. Sediments consist mainly of sand and pebbles, while the flux of suspended matter from rivers locally increases the share of finer fractions. Analysis of species composition (419 taxa), abundance (up to 4,200 ind m⁻² and up to 29,000 ind m⁻² with juveniles) and biomass (up to >6,000 g wet wt m⁻²) indicates high species richness in most parts of the bay, especially in the northeast. Analysis of community structure using production characteristics of species revealed a general predominance of suspension feeders partitioned into seven communities. The dominant species of these communities were Mytilus edulis and Balanus crenatus (Type 1), B. crenatus (Type 2), Modiolus modiolus and Verruca stroemia (Type 3), Flustra foliacea and V. stroemia (Type 4), Hydrallmania falcata (Type 5), V. stroemia and Chirona hameri (Type 6), and Ophelia limacina (Type 7). The structure of the communities is mainly regulated by sediment type, water depth and, to some extent, by riverine input. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.