Clayey Substrate Research Articles

Ecological Speciation without Morphological Differentiation? A New Cryptic Species of Diodontus Curtis (Hymenoptera, Pemphredonidae) from the Centre of Europe.

Upon exploring the mitotype diversity of the aphid-hunting wasp, Diodontus tristis, we revealed specimens with highly divergent mitotypes from two localities in Lithuania and nesting in clayey substrate, while the specimens with typical mitotypes were found nesting in sandy sites. The comparison of inter- and intra-specific distances and application of delimitation algorithms supported the species status of the clay-nesting populations. Using a set of DNA markers that included complete or partial sequences of six mitochondrial genes, three markers of ribosomal operon, two homeobox genes, and four other nuclear genes, we clarified the phylogenetic relationships of the new cryptic species. The endosymbiotic bacteria infestation was checked, considering the option that the divergent populations may represent clades isolated by Wolbachia infection; however, it did not demonstrate any specificity. We found only subtle morphological differences in the new clay-nesting species, D. argillicola sp. nov.; the discriminant analysis of morphometric measurements did not reliably segregate it as well. Thus, we provide the molecular characters of the cryptic species, which allow confident identification, its phylogenetic position within the genus, and an updated identification key for the D. tristis species group.

Effect of kinetics, pH, aqueous speciation and presence of ferrihydrite on vanadium (V) uptake by allophanic and smectitic clays

Sorption of oxyanions, such as pentavalent vanadium (V(V)), by reactive, poorly crystallized clay minerals and Fe-(hydr)oxides surfaces significantly contributes to the nutrient and pollutant transport in soils. However, only a few studies yet exist, which evaluate and quantify the role of such common soil substituents on V sorption. In this contribution, the uptake of V(V) by allophane with molar Al/Si ratios of 1.5 (ALO-1) and 1.8 (ALO-2) and by montmorillonite-beidellite (MNT-BEI) clays was investigated using kinetic and equilibrium experiments. The effects of pH, V speciation, contact time and presence of 6-line ferrihydrite (FHY) were evaluated at 25 °C. The clayey substrates with(out) FHY were characterized using X-ray diffraction, X-ray fluorescence, high-resolution transmission electron microscopy with energy-dispersive X-ray spectroscopy and selected area electron diffraction and N2-Brunauer-Emmett-Teller physisorption methods. Fast (≥ 15 min) adsorption of V(V) was followed by pseudo-first-order reaction kinetics and progressed through instantaneous diffusion processes at the exterior surface. Subsequently, V(V) transportation and adsorption within the interior substrate, as inferred from Weber-Morris intra-particle diffusion model plots, was observed. The presence of FHY had a positive effect on V(V) adsorption ([V]T = 0.02 mmol/L), which followed in the order MNT-BEI-FHY and MNT-BEI (≥ 95% removal), ALO-1-FHY and ALO-2-FHY (≥ 90% removal), ALO-1 (≥ 70% removal) and ALO-2 (≥ 40% removal) in the pH range from ~6 to ~8. The results of this study demonstrate the high affinity of ferrihydrite as well as allophanic and smectitic clays for V(V) adsorption, suggesting that these components can limit the V mobility in soils over a wide pH range.

Pioneer biocrust communities prevent soil erosion in temperate forests after disturbances

Abstract. Soil erosion continues to be one of the most serious environmental problems of our time and is exacerbated by progressive climate change. Until now, forests have been considered an ideal erosion control. However, even minor disturbances of the forest floor, for example, from heavy vehicles used for timber harvesting, can cause substantial sediment transport. An important countermeasure is the quick restoration of the uncovered soil surface by vegetation. To date, very little attention has been paid to the development of nonvascular plants, such as bryophytes, in disturbed areas of temperate forests and their impact on soil erosion. This study examined the natural succession of pioneer vegetation in skid trails on four soil substrates in a central European temperate forest and investigated their influence on soil erosion. For this purpose, rainfall simulations were conducted on small-scale runoff plots, and vegetation was continuously surveyed during the same period, primarily to map the development of bryophytes and the occurrence of biological soil crusts (biocrusts). Biocrusts appeared immediately after disturbance, consisting primarily of bryophyte protonemata and cyanobacteria as well as coccoid and filamentous algae that lost their biocrust characteristics as succession progressed. They were present from April to July 2019, with a particular expression in the skid trail that was on shale clay (Psilonotenton Formation) and silty clay loam substrate. In general, skid trails on clayey substrates showed considerably higher bryophyte cover and species richness. Although bryophytes were subsequently overtopped by vascular plants, they managed to coexist until their growth was restricted due to leaf litter fall. Brachythecium rutabulum and Oxyrrhynchium hians were the most important and persistent pioneer bryophyte species, while Dicranella schreberiana and Pohlia lutescens were volatile and quickly disappeared after spreading in the summer. Sediment discharge was 22 times higher on disturbed bare soil compared with undisturbed forest soil and showed the largest sediment removal in the wheel tracks. Counteracting this, soil erosion decreased with the recovery of surface vegetation and was particularly reduced with growing pioneer biocrusts in summer, but it again increased in winter, when vascular vegetation became dominant. This leads to the conclusion that the role of bryophyte-dominated biocrusts in forests has been underestimated so far, and they can contribute more to soil conservation at specific times of succession than vascular plants.

Marine transgression(s) to evaporite basin: The case of middle Miocene (Badenian) gypsum in the Central Paratethys, SE Poland

The middle Miocene Badenian evaporite basin of the Carpathian Foredeep Basin was a saline lake, separated by a barrier from the sea and supplied with seawater seeping through the barrier or overflowing it occasionally in the form of short-lived marine transgressions. Such transgressions could leave behind marine microfossils in marly clay intercalations. One of them (2.3 m thick) occurs in the uppermost part of the sulphate sequence, in the unit ‘o’, in the Babczyn 2 borehole section. It contains marine palynomorphs (dinoflagellate cysts) and foraminiferal assemblages indicating a marine environment. The low-diversity benthic foraminiferal assemblages are dominated by opportunistic, shallow infaunally living species, preferring muddy or clayey substrate for thriving, brackish to normal marine salinity, and inner shelf environment. Dinoflagellate cyst assemblages, although taxonomically impoverished, consist of marine species; euryhaline forms that tolerate increased salinity are missing. Relatively common microfossils found in clay intercalations within gypsum have important palaeogeographical implications: they strongly suggest that there existed an additional inflow channel supplying the Polish Carpathian Basin from the south during the evaporite deposition and afterwards.

Two new species of the genus Lepidophthalmus (Decapoda, Axiidea,Callianassidae) from coastal Pacific waters of Central America.

Two new species of intertidal ghost shrimp are described from coastal Central American habitats of the eastern Pacific Ocean, bringing the total known membership of the genus to 18 species. Lepidophthalmus natesi sp. nov. from Colombia and Nicaragua shares with Lepidophthalmus panamensis sp. nov. from Colombia and Panama the lack of extensive ventral pleomere armor, especially in lacking a median ventral sclerite on the second pleomere. The absence of this plate is also a character of the eastern Pacific species L. rafai Felder & Manning, 1998, but the two new species differ from it in telson shape. Ventral armor including this plate is present in Lepidophthalmus bocourti (A. Milne-Edwards, 1870) and L. eiseni Holmes, 1904 which occur sympatrically with L. natesi sp. nov. in eastern Pacific tropical estuaries. As also known for at least L. bocourti, L. natesi sp. nov. invades and densely colonizes penaeid shrimp aquaculture ponds in regional estuarine settings. Individuals of L. panamensis sp. nov. are of smaller body size but also may be densely concentrated, especially in clayey substrates including those adjacent to intertidal rocks. Despite their similarities in the pleon and shape of the telson, the species can be readily separated by dentition of the cheliped fingers, relative length of the minor chela fingers, the second pleopod appendix of mature males, and egg size. The large eggs of L. panamensis sp. nov. suggest extremely abbreviated development. Characteristic coloration is described for both new species.

Guzhangian (mid Cambrian) trilobites from siliceous concretions of the Valtorres Formation, Iberian Chains, NE Spain

AbstractIn the carbonate-siliciclastic strata of West Gondwana (e.g. in the Montagne Noire, France), the aftermath of the mid Languedocian (mid Cambrian) regression is characterized by a late Languedocian major turnover of trilobite families and a Furongian–early Tremadocian radiation related to the stepwise immigration of trilobite invaders from East Gondwana under persistent transgressive conditions. The scarcity of upper Languedocian fossil accumulations in clayey substrates has inspired the sampling of the palaeogeographically most distal parts of the Iberian Chains (Spain), where diagenetic dissolution of ubiquitous hexactinellid sponge spicules has favoured the formation of siliceous concretions. These have yielded the trilobitesPeronopsiscf.insignis,Oidalagnostus trispinifer,Proampyx difformis(=Proampyx aculeatus),Bailiaspis?glabrata(=Holocephalina agrauloides, by ontogeny),Holasaphuscf.centropygeand a paradoxidid gen. et sp. indet. Despite preservation and sampling biases, the identification of this taphonomic window in offshore clayey substrates of West Gondwana allows the recognition of a strong biogeographical link with Baltica, and the correlation of the global Guzhangian Stage and theSolenopleura?brachymetopaZone of Scandinavia with part of the Mediterranean upper Languedocian Substage.

Effects of land use changes on badland erosion in clayey drainage basins, Radicofani, Central Italy

Hillslopes of the Radicofani area, in the upper valley of the Orcia River (southern Tuscany region, Italy), consist mainly of early Pliocene clayey sediments and are widely affected by frequent badland erosion. Reforestation with frugal conifers has been carried out in the area over the last 50years. The goal of the present study is to evaluate the impact of reforestation and land use change on erosion rates in nine small drainage basins through a multidisciplinary approach. Geological, geomorphological, hydrological and land use characteristics were analyzed by a diachronic confrontation between pre-reforestation (1954) and post-reforestation (2007) situations. Aerial-photo interpretation and processing in GIS allowed us to quantify changes in areas affected by badland erosion, land use and variations in erosion rates. Moreover, dendrometric data were gathered from 18 circular sample plots in forest stands of 40years old. This allowed us to evaluate both the adaptability of different forest species to the clayey substrate and reforestation fragmentation. The differences between the pre- and post-reforestation situations led to increases in arable land and forest areas and considerable decreases in erosion rates and badland areas. However, no significant correlation between the erosion rates and the forest area emerged, due to the excessive fragmentation of reforestation cores and relatively small reforested surfaces. Land reclamation seems to have played a more important role in reducing erosion in the clayey substrate. The integrated method presented here is an important tool useful to understand the morphological dynamics of badlands in relation to forest vegetation, and for land planning and management.

Allelopathic effect of Salix caprea litter on late successional plants at different substrates of post-mining sites: pot experiment studies

The willow Salix caprea L. is a common colonizer of post-mining sites including those in the Sokolov coal mining district (Czech Republic) where this study was conducted. In one bioassay and two pot experiments, we investigated the effect of S. caprea litter on three plant species ( Arrhenatherum elatius (L.) P. Beauv. ex J. Presl & C. Presl, Plantago lanceolata L., and Lotus corniculatus L.) that commonly grow in late successional stages on these sites. In a sandy soil, leachate from fresh S. caprea litter reduced the number of germinated individuals (experiment 1) and shoot and root growth (experiment 2). In the clayey substrate originally unaffected by the S. caprea (experiment 3) leachate suppressed germination of all three species, but no reduction of biomass (both aboveground and belowground) was observed. Biomass was enhanced, however, in substrate that was naturally enriched with S. caprea litter (i.e., substrate collected on the same locality as previously mentioned substrate but beneath the S. caprea shrubs). Salix caprea therefore can suppress the establishment of new plants that arrive as seeds, but this suppression may only occur with seeds that directly contact the litter. When S. caprea litter is incorporated into the substrate, it can considerably improve substrate quality and the growth of successional plants.

Surface soil moisture quantification models from reflectance data under field conditions

A new approach to estimate surface soil moisture from reflectance data in the solar spectral range (350–2500 nm) is presented, called the Normalized Difference Soil Moisture Index (NSMI). The motivation for this new index is to make use of spectral features that fulfill the criteria of robustness against covariates, physical comprehensibility and easy applicability in the field and from remote sensing platforms. Spectral measurements were taken in the laboratory from 121 prepared as well as 467 natural soil samples consisting of different sands and clayey substrates originating from a lignite mine reclamation site. While the preparation procedure performed on samples from the first group removed the covariates' influence on the reflectance spectra, the natural samples in the second group maintained the influencing factors like impurity, crusts, and organic matter. In a systematic way all wavelengths were combined in different spectral feature approaches and optimum bands or band combinations were found for linear correlation with soil moisture. For the natural samples, the NSMI achieved best results in this study with R 2 of 0.61 by combining reflectance values at 1800 and 2119 nm. This value increased to 0.71 when samples with significant xylite proportions had been removed. Analyses on the effect of single covariates showed that neither surface crusts nor substrate heterogeneity changed the correlation between soil moisture and the NSMI significantly. The NSMI can therefore be seen as a new index for quick assessment of surface or near‐surface soil moisture directly in the field using spectral instruments.

A review of the Late Cambrian (Furongian) palaeogeography in the western Mediterranean region, NW Gondwana

The Cambrian–Ordovician transition of the western Mediterranean region (NW Gondwana) is characterized by the record of major erosive unconformities with gaps that range from a chronostratigraphic stage to a series. The hiatii are diachronous and involved progressively younger strata along the Gondwanan margin, from SW (Morocco) to NE (Montagne Noire). They can be related to development of a multi-stage rifting (further North), currently connected to the opening of the Rheic Ocean, and concomitant erosion on southern rift shoulders. The platforms of this margin of Gondwana occupied temperate-water, mid latitudes and were dominated by siliciclastic sedimentation, while carbonate factories were only episodically active in the Montagne-Noire platform. The Upper Cambrian is devoid of significant gaps in the southern Montagne Noire and the Iberian Chains. There, the sedimentation took place in a transgressive-dominated depositional system, with common offshore deposits and clayey substrates, and was bracketed by two major regressive trends. The Late Cambrian is also associated with the record of volcanic activity ( e.g., in the Cantabrian and Ossa-Morena zones, and the northern Montagne Noire), and widespread development of a tectonic instability that led to the episodic establishment of palaeotopographies and record of slope-related facies associations. Several immigration events are recognized throughout the latest Middle Cambrian, Late Cambrian and Tremadocian. The trilobites show a stepwise replacement of Acado-Baltic-type families ( e.g., the conocoryphid–paradoxidid–solenopleurid assemblage) characterized by: (i) a late Languedocian (latest Middle Cambrian) co-occurrence of Middle Cambrian trilobite families with the first anomocarid, dorypygid and proasaphiscid invaders; (ii) a Late Cambrian immigration replacing previous faunas, composed of trilobites (aphelaspidids, catillicephalids, ceratopygids, damesellids, eulomids, idahoiids, linchakephalids, lisariids, onchonotinids, and pagodiids), linguliformean brachiopods (acrotretids, obolids, scaphelasmatids, siphonotretids, and zhanatellids), echinoderms (mitrates, glyptocystitid cystoids, and stromatocystoids), and conodonts belonging to the lower Peltura Zone; and (iii) the subsequent input of new trilobites (asaphids, calymenids, catillicephalids, nileids and remopleurids), which marks the base of the Proteuloma geinitzi Zone, associated with pelmatozoan holdfasts ( Oryctoconus), and a distinct input of late Tremadocian conodonts ( Paltodus deltifer Zone). The biogeographic distribution of latest Middle and Late Cambrian trilobites supports brachiopod data indicating strong affinities between the western Mediterranean region, East Gondwana (North China/Korea, South China, Australia, and Antarctica) and Kazakhstania during the late Languedocian, which became significantly stronger during the Late Cambrian. This major shift may suggest modification in oceanic circulation patterns throughout Gondwana across the Middle–Late Cambrian transition.

Functional Differences Among Benthic Macroinvertebrate Communities in Reference Streams of Same Order in a Given Biogeographic Area

Ecological theory (Southwood, 1977. Journal of Animal Ecology 46: 337–365, 1988. Oikos 52: 3–18; Townsend, 1989. Journal of the North American Benthological Society 8: 36–50; Townsend & Hildrew, 1994. Freshwater Biology 31: 265–275) considers that spatio-temporal variations in habitats act as evolutionary forces on organisms, selecting for traits that maximize fitness. As a consequence, communities developed under same environmental conditions should present the same combination of species bio-ecological characteristics. The objective was to verify, using data from the same biogeographical zone, (1) if there was a unique suite of bio-ecological profiles for reference macrobenthic communities of `comparable' rivers or (2) if the distribution of bio-ecological traits within reference communities was significantly influenced by geology. The variability of 22 bio-ecological traits in 12 different sites was tested to evaluate the potential influence of geological substrate on biological and ecological features of reference stream communities. Observed patterns suggested that communities displayed highly stable bio-ecological profiles among sites (within a given biogeographical zone) whatever the substrate was, even if communities on clayey substrate exhibited slightly different bio/ecological characteristics than on others geologies. Nevertheless, the functional structure of macrobenthic communities in reference sites was quite stable in this biogeographical area. This study was restricted to the selected stream types and its results may not directly be transferred to other biogeographical areas and stream types. However, the perspective of a unique functional reference for streams of the same order in a given biogeographical area, improve functional comparison between observed vs. reference communities. This could simplify and objectively define the ecological status of a given site.

Hydrogeologic and Geochemical Factors Required for the Development of Carolina Bays Along the Atlantic and Gulf of Mexico Coastal Plain, USA

More than 60 years of intense study and debate have yet to resolve the origin of the Carolina Bays. Carolina Bays are circular to elliptical depressions located along the Gulf of Mexico and Atlantic Coastal Plains. Proposed processes of initiation and development of these karst-like features include meteorite impacts, substrate dissolution, wind, ice, marine waves and currents. Based on field studies throughout the Atlantic and Gulf Coastal Plains and on review of coastal plain literature, we propose that Carolina Bays initially developed as silica-karst features. During Pleistocene sea-level lowstands, water tables in the Atlantic Coastal Plain were up to 30 m lower than today. Large volumes of surface water collected in local topographic lows and/or areas of enhanced permeability and infiltrated through sandy substrates of the low-relief coastal plain. Localized infiltration of phreatic water induced extensive desilicification of the sandy and clayey substrates, resulting in volume loss and development of karst-like depressions. Particularly relevant to initial bay development was alteration of kaolinite to gibbsite, which can produce a 34-percent loss in clay material volume, and concurrent dissolution of iron oxide. The initial silica-karst depressions along the Atlantic and Gulf coasts were later modified by eolian and, perhaps, ice-push processes, which enhanced their elliptical form. The subsequent Holocene rise in sea level caused ground-water levels in the coastal plain to equilibrate near the present-day land surface. This curtailed geochemical weathering, as well as eolian and ice-related processes. Ground-water saturation partially reversed chemical reactions associated with intensive weathering of clays beneath the bays, masking evidence of the severe leaching that occurred during their initial formation. Silica-karst features, similar to Carolina Bays in their initial stages of development, are common geologic features. Moreover, silica-karst processes are active today in warm temperate, subtropical, and tropical areas in sandy substrates where groundwater levels are well below the ground surface and can cause subsidence or disrupt developing wetlands.

Evidence from Paleosols for the Geological Antiquity of Rain Forest

Kaolinitic claystones in Paleozoic paleokarst underlying the Middle Pennsylvanian Fort Scott Limestone near Drake, Missouri, contain abundant fossil root traces. These include a surficial root mat as well as stout, woody, deeply penetrating root traces: a rooting pattern similar to that under rain forest. Also similar to soils of rain forest is the deeply weathered clay of the paleosol, in which minimal amounts of nutrient bases remain. Forest communities adapted to oligotrophic clayey substrates in humid climates existed at least 305 million years ago.

The effect of environmental factors on the nesting and courtship behaviour ofTilapia zillii in Lake Kinneret (Israel)

Tilapia zillii is a polyphilic, guarding nest spawner which is widespread in west and north Africa and in the Middle East. A study of the nesting and courtship behaviour of this species in Lake Kinneret (Sea of Galilee), revealed that nesting and brood care differ according to the exposure of the nesting site to wave action and the nature of the substrate. The nests are simple and parental care is abbreviated in exposed, sandy sites whereas elaborate nests with brood chambers are excavated in sheltered areas with clayey substrates, and parental care is extensive. The implications of these findings to studies on cichlid breeding and the conservation ofT. zillii in Lake Kinneret are discussed.

Earth Flows Along Henry Creek, Northern Alaska

Many earth flows occurred during the summer of 1979 in the hilly terrain near Umiat, Alaska, particularly along Henry Creek. Most were shallow, involving only the tundra mat and no more than 1.5 m of the underlying mud. The summer of 1979 was the warmest and wettest for the period of record at Umiat, and precipitation was characterized by brief but intense localized rainstorms. Failure probably was triggered by the heavy rains and facilitated by an absorbent tundra mat over a clayey substrate, and perhaps in some cases by a thicker than normal active layer. Flows of this kind have occurred repeatedly in the Uniat area, most likely during summers in which climatic conditions were similar to those of 1979.Key words: earth flows, rainfall, temperature, active layer, bentonitic materials, Alaska

Two New Deep-Sea Cirripedia (Ascothoracica and Acrothoracica) From the Atlantic

Two new deep-sea barnacles (Cirripedia) are described. The first, from approximately 5200 m in the Southwest Atlantic, belongs to the most generalized genus of the order Ascothoracica, Synagoga. The two previously known species, S. mira from the Mediterranean and S. metacrinicola from Japan, are from relatively shallow water. The new species is not only more generalized than either of these, but it exceeds previous depth records for any ascothoracican by more than 1000 m. It is apparently a sequentially protandric hermaphroditic ectoparasite, knowledge of which helps clarify difficulties in interpreting the life histories of certain more highly evolved endoparasitic forms. On the other hand, its markedly generalized features bear heavily on considerations of the origin of the Maxillopoda.The second new species, from approximately 1500 m in the Bay of Biscay, belongs to the most generalized genus of the order Acrothoracica, Weltneria. It is closely related to W. hessleri known from 1000 m off Bermuda and the two are unique in being the only true deep water members of the order. The new species is remarkable in inhabiting a friable, clayey substrate - all other acrothoracicins are known to burrow only in relatively solid forms of calcium carbonate. However, both have a calcified rostral plate, and this indicates that the Acrothoracica stem from scalpellid rather than cyprilepadid or iblid Lepadomorpha.

Macro-Invertebrate Assemblages of Central Texas Coastal Bays and Laguna Madre

A study of the distribution of macrofauna and the ecological factors affecting their distribution in the bays and lagoons of the central and south Texas coast has made it possible to formulate a series of criteria for interpreting modern and ancient depositional environments. The observations reported in this paper cover a 7-year period. In addition, some information was available covering a period of 30 years. The central Texas bays are situated in a variable climate, and the faunas reflect long-term changes in rainfall and temperature. Four major environments are recognized on the basis of macro-invertebrate assemblages: (1) river-influenced low-salinity bays and estuaries characterized by Rangia and amnicolids; (2) enclosed bays, dominated by oyster reefs composed of Crassostrea virginica; (3) open bays and sounds characterized by Tagelus divisus, Chione cancellata, and Macoma constricta; and (4) bay and lagoon regions strongly influenced by inlets characterized by a mixed Gulf and bay fauna. Smaller sub-facies needing more information for recognition are: (1) bay margins, (2) oyster reefs exhibiting marine influence, (3) bay centers, and (4) shallow grassy bays in the vicinity of inlets. Five assemblages were recognized in Laguna Madre which are related to the physiography of the Laguna Madre: (1) shallow hypersaline area near inlet characterized by forms common to the Gulf and normal salinity bays on the north; (2) open hypersaline lagoon characterized by Amygdalum papyria and other forms attaching to vegetation; (3) enclosed hypersaline lagoon with tremendous numbers of two pelecypods, Anomalocardia cuneimeris and Mulinia lateralis; (4) relatively deep hypersaline bay with clayey substrate with virtually no living macro-invertebrates; and (5) hypersaline lagoon with normal bay influence, occupied by many of the species typical of an open bay plus Anomalocardia and Mulinia. The application of macrofaunal assemblages to the interpretation of older sediments was demonstrated in a study of a series of borings taken in the Rockport area. The macrofaunal evidence indicates that the Rockport bays have undergone at least one marine transgression in the past 9,000 years.