Burrows Research Articles

BULLDOZING AND RESTING TRACES OF FRESHWATER MUSSEL ANODONTA WOODIANA AND SUBSTRATE CHARACTERISTICS IN LAKE-MARGIN AND RIVER SETTINGS OF UMBRIA, ITALY

The neoichnology of the freshwater mussel Anodonta ( Sinanodonta ) woodiana (Lea, 1834) is examined herein in some continental environments of Umbria (central Italy), such as lake-margin and river dam-margin settings. This study, based on analysis of about 200 traces, reveals that this mussel burrows employing two types of behaviours: bulldozing which produces horizontal meanders to straight bilobate traces, often filled with peloidal faecal pellets (pseudofaeces and backfill), and resting (vertical stationary into substrate) while filter feeding. A new type of very soft substrate, the ‘cloudground’ is proposed. It is placed at the water-sediment interface, above the soupground. After four years of observation, the cloudground was buried with shells and traces, preserving through the fossilization barrier about 20% of the Anodonta traces. This bivalve activity is a useful tool to recognize preservation of mud in quiet environments and parallels ichnological evidence of unknown epichnial trace fossils in the continental realm. Cloudground with resting traces must be investigated also in modern marine basin floor environments where cloud of mud dominates and considered also in geological record.

Model of burrow selection predicts pattern of burrow switching by Leach's Storm-Petrels

Patterns of nest site selection exhibited at the scale of a population should result from initial preferences of individuals occupying nest sites as well as preferences exhibited by individuals moving between nest sites. We tested whether nest-site preferences measured at the population scale were predictive of patterns of burrow switching by Leach's Storm-Petrels (Oceanodroma leucorhoa), a long-lived seabird that nests in underground burrows. Breeding pairs generally choose from the pool of available existing burrows rather than constructing new burrows, and a portion of the burrows in a colony remains unused in any breeding season. We quantified burrow preference at a colony on Kent Island, New Brunswick, over four breeding seasons. We used a classification and regression tree analysis to build a predictive model of nest-site selection. Preferentially occupied burrows were drier, longer, had larger nest chambers, and were in areas of higher burrow density. To measure preferences during burrow switching, we tracked individuals that switched burrows, comparing characteristics of the burrows in which these birds were originally found to those they inhabited at the end of the study period. Characteristics preferred by switching individuals were a subset of those observed at the scale of the population; individuals moved to burrows that were drier, longer, and had larger nest chambers. Our results show how preferences of individuals that move between nest sites contribute to nest site preferences exhibited at the population scales commonly tested. RESUMEN Modelo de la seleccion de cavidades permite predecir el patron de cambio de estas en Oceanodroma leucorhoa El patron de seleccion del lugar en donde anidar, exhibido a escala de una poblacion, debe ser el resultado de preferencias individuales de organismos que ocupan lugares para anidar, e igualmente de preferencias exhibidas por individuos que cambian de lugar para anidar. Pusimos apruebas si las preferencias, medidas a escala de poblacion, podian ser utilizadas para predecir el patron de cambio de cavidades de parte de Oceanodroma leucorhoa, que es un ave marina que anida en cavidades bajo tierra. Las parejas usualmente seleccionan entre un grupo de cavidades disponibles, en vez de estos construir la propia, y una porcion de las cavidades permanecen sin ser utilizadas a lo largo de la epoca de reproduccion. Cuantificamos la preferencia de uso de cavidades en una colonia localizada en la Isla Kent, New Brunswick, durante cuatro temporadas reproductivas. Utilizamos una clasificacion y un analisis de regresion para construir un modelo de prediccion para la seleccion de lugar de anidar. Los lugares ocupados, con preferencia, se mantenian secos, eran largos, de mayor tamano y se encontraban en lugares con alta densidad de cavidades. Para determinar las preferencias en el cambio de uso de cavidades, seguimos a individuos que cambiaron de cavidad, y compararnos las caracteristicas del lugar utilizado originalmente, con aquellas cavidades siendo utilizadas al final del estudio. Las caracteristica preferidas, por individuos que cambiaron de cavidad, eran un subconjunto de aquellas observadas a nivel poblacional. Las aves se movieron a cavidades mas secas, mas largas y con una camara de anidamiento mas amplia. Nuestros resultados muestran como las preferencias individuales, de aves que se mueven a otras cavidades para anidar, contribuyen a las preferencias del lugar de anidamiento exhibido a escala poblacional.

The characteristics of carbonate system recovery during a relatively dry event in a mixed carbonate/siliciclastic environment in the Pelsonian (Middle Triassic) proximal marginal marine basins: A case study from the tropical Tethyan northwest Gondwana margins

Eight early-mid Pelsonian (Middle Triassic) marine sedimentary successions, an outcrop and subsurface sections of the Ra'af Formation from the northwest Gondwana margins facing the southeast corner of the tropical western Tethyan seaway assigned to the southern Intertropical Convergence Zone (ITCZ) (south Israel, Levant Basin, north Arabian plate) are the focus of this work. The successions, especially with the exclusive outcrop at Har 'Arief, are a golden opportunity to observe the still connected transitional zone between the huge siliciclastic domains derived from Gondwana hinterland parts (north Arabian plate) and the open, tropical Tethyan marine carbonate domain and their mutual relationships.This multidiscipline research tracks a carbonate recovery attempt in a dominant siliciclastic system. The recovery effort was characterized by starved sedimentary conditions, basin-constrained oxygen-stressed environments, and low-diverse, autochthonous burrowed sediments barren of other faunal remains. Low-diverse fossiliferous allochthonous beds, transported from higher sites on the slopes, revealed differential distributions of echinoids, mollusks and especially foraminifera (large Pilammina-Pilamminella versus small glomospirids); these variances were attributed to different environmental conditions on the slopes of each basin-type and illuminate some constraints on their distribution pattern and climate affinity in the Triassic, southern ITCZ mixed carbonate/siliciclastic, sedimentary system. The carbonate recovery phase is ascribed to a relatively dry period in the hinterland rather than to sea-level rise; this dry period, which interrupted the relatively humid climate in the northern tropical Gondwana during the Pelsonian, is represented by the constant, although with some perturbations, siliciclastic sedimentary system that prevailed in the southeastern corner of the Tethys seaway during the Anisian. Insights from the symmetric and asymmetric correlation of climate fluctuations in the hinterlands of the southeastern European basins (northern hemisphere) and this work (from the southern hemisphere), both embracing basins ascribed to the western tropical Tethyan seaway, illuminate the possible effects of the ICTZ behavior pattern and possible extra-tropical forces on the climate variations.

The regulation of copper stress response genes in the polychaete Nereis diversicolor during prolonged extreme copper contamination.

Polychaetes are frequented in toxicological studies, one reason being that some members occupy shallow burrows in sediments and are maximally exposed to the contaminants that accumulate within them. We have been studying one population of the polychaete Nereis (Hediste) diversicolor exhibiting inheritable tolerance to extreme copper contamination in estuarine sediment. Using transcriptome sequencing data we have identified a suite of genes with putative roles in metal detoxification and tolerance, and measured their regulation. Copper tolerant individuals display significantly different gene expression profiles compared to animals from a nearby population living without remarkable copper levels. Gene transcripts encoding principle copper homeostasis proteins including membrane copper ion transporters, copper ion chaperones and putative metallothionein-like proteins were significantly more abundant in tolerant animals occupying contaminated sediment. In contrast, those encoding antioxidants and cellular repair pathways were unchanged. Nontolerant animals living in contaminated sediment showed no difference in copper homeostasis-related gene expression but did have significantly elevated levels of mRNAs encoding Glutathione Peroxidase enzymes. This study represents the first use of functional genomics to investigate the copper tolerance trait in this species and provides insight into the mechanism used by these individuals to survive and flourish in conditions which are lethal to their conspecifics.

Observations on the use of tarantula burrows by the anurans Leptodactylus bufonius (Leptodactylidae) and Rhinella major (Bufonidae) in the Dry Chaco ecoregion of Bolivia

February Abstract. Some species of anurans have been observed utilizing burrows of other animals, such as rodents and taran- tulas. Here we report the observations of two anuran species, Leptodactylus bufonius and Rhinella major, utilizing the burrows of tarantulas (Acanthoscurria sp.; Family Theraphosidae) in the dry Chaco ecoregion of Bolivia. Both species of anurans never co-occurred with tarantulas in the burrows and used burrows that were wider in diameter and closer to breeding ponds as compared to the total available tarantula burrows in the area. These burrows may serve as ref- uges from predators, especially for conspicuous, calling males.

Energy metabolism and regeneration are impaired by seawater acidification in the infaunal brittlestar Amphiura filiformis.

Seawater acidification due to anthropogenic release of CO2 as well as the potential leakage of pure CO2 from sub-seabed carbon capture storage (CCS) sites may impose a serious threat to marine organisms. Although infaunal organisms can be expected to be particularly impacted by decreases in seawater pH, as a result of naturally acidified conditions in benthic habitats, information regarding physiological and behavioral responses is still scarce. Determination of PO2 and P(CO2) gradients within burrows of the brittlestar Amphiura filiformis during environmental hypercapnia demonstrated that besides hypoxic conditions, increases of environmental P(CO2) are additive to the already high P(CO2) (up to 0.08 kPa) within the burrows. In response to up to 4 weeks exposure to pH 7.3 (0.3 kPa P(CO2)) and pH 7.0 (0.6 kPa P(CO2)), metabolic rates of A. filiformis were significantly reduced in pH 7.0 treatments, accompanied by increased ammonium excretion rates. Gene expression analyses demonstrated significant reductions of acid-base (NBCe and AQP9) and metabolic (G6PDH, LDH) genes. Determination of extracellular acid-base status indicated an uncompensated acidosis in CO2-treated animals, which could explain the depressed metabolic rates. Metabolic depression is associated with a retraction of filter feeding arms into sediment burrows. Regeneration of lost arm tissues following traumatic amputation is associated with significant increases in metabolic rate, and hypercapnic conditions (pH 7.0, 0.6 kPa) dramatically reduce the metabolic scope for regeneration, reflected in an 80% reduction in regeneration rate. Thus, the present work demonstrates that elevated seawater P(CO2) significantly affects the environment and the physiology of infaunal organisms like A. filiformis.

Impacts of bioturbation on temporal variation in bacterial and archaeal nitrogen-cycling gene abundance in coastal sediments.

In marine environments, macrofauna living in or on the sediment surface may alter the structure, diversity and function of benthic microbial communities. In particular, microbial nitrogen (N)-cycling processes may be enhanced by the activity of large bioturbating organisms. Here, we study the effect of the burrowing mud shrimp Upogebia deltaura upon temporal variation in the abundance of genes representing key N-cycling functional guilds. The abundance of bacterial genes representing different N-cycling guilds displayed different temporal patterns in burrow sediments in comparison with surface sediments, suggesting that the burrow provides a unique environment where bacterial gene abundances are influenced directly by macrofaunal activity. In contrast, the abundances of archaeal ammonia oxidizers varied temporally but were not affected by bioturbation, indicating differential responses between bacterial and archaeal ammonia oxidizers to environmental physicochemical controls. This study highlights the importance of bioturbation as a control over the temporal variation in nitrogen-cycling microbial community dynamics within coastal sediments.

Bioturbation determines the response of benthic ammonia-oxidizing microorganisms to ocean acidification

Ocean acidification (OA), caused by the dissolution of increasing concentrations of atmospheric carbon dioxide (CO2) in seawater, is projected to cause significant changes to marine ecology and biogeochemistry. Potential impacts on the microbially driven cycling of nitrogen are of particular concern. Specifically, under seawater pH levels approximating future OA scenarios, rates of ammonia oxidation (the rate-limiting first step of the nitrification pathway) have been shown to dramatically decrease in seawater, but not in underlying sediments. However, no prior study has considered the interactive effects of microbial ammonia oxidation and macrofaunal bioturbation activity, which can enhance nitrogen transformation rates. Using experimental mesocosms, we investigated the responses to OA of ammonia oxidizing microorganisms inhabiting surface sediments and sediments within burrow walls of the mud shrimp Upogebia deltaura. Seawater was acidified to one of four target pH values (pHT 7.90, 7.70, 7.35 and 6.80) in comparison with a control (pHT 8.10). At pHT 8.10, ammonia oxidation rates in burrow wall sediments were, on average, fivefold greater than in surface sediments. However, at all acidified pH values (pH ≤ 7.90), ammonia oxidation rates in burrow sediments were significantly inhibited (by 79-97%; p < 0.01), whereas rates in surface sediments were unaffected. Both bacterial and archaeal abundances increased significantly as pHT declined; by contrast, relative abundances of bacterial and archaeal ammonia oxidation (amoA) genes did not vary. This research suggests that OA could cause substantial reductions in total benthic ammonia oxidation rates in coastal bioturbated sediments, leading to corresponding changes in coupled nitrogen cycling between the benthic and pelagic realms.

The rise of the diptera‐microbial mat interactions during the Cenozoic: consequences for the sedimentary record of saline lakes

AbstractShoreline gypsiferous sediments of an inland lake in central Spain furnishes valuable insight into reconstructions of early sedimentary changes related to shore fly–microbial mat interactions in fossil gypsum precipitating saline lake systems. The association of adult and larval forms of Ephydra (Diptera) with microbial matgrounds overlying the lake margin results in the formation of gypsiferous meniscate back‐filled burrows that provide an analogue for recurring, extensively developed trace fossils that occur in Cenozoic, but not older, lacustrine gypsum rocks. In this setting, sediment burrowing by ephydridae hinders significant preservation of microbialites. The overwhelming rise of Diptera at the onset of the Cenozoic resulted in extensive feeding and dwelling activity and contributed to reshape the saline aquatic habitat where microbial mats thrived, thus leading to the formation of specific trace fossils that are illustrative of the existence of microbes in the paleoenvironment.

Spatial distribution of Alitta virens burrows in intertidal sediments studied by axial tomodensitometry

Relationships between sediment characteristics and the spatial organization of biogenic structures remain poorly understood, albeit important for characterizing bioturbation impacts and small-scale ecological patterns. Using axial tomodensitometry (CT-scan) and core sectioning, we studied the spatial distribution of Alitta virens burrows in sediment cores from two mudflats with different degrees of exposure along the St Lawrence Estuary, Canada. A variety of burrow morphologies was observed at both sites, with most being I-shaped. Most values measured (organic matter content, mean tomographic intensity, the number and diameter of burrow shafts and the percentage of space they occupy per transverse section) covaried with depth. The more sheltered site had higher organic matter and mud contents, and lower average tomographic intensity values. The spatial distribution of burrow shafts also differed between sites, with the more sheltered site having a higher number of burrow shafts and percentage of biogenic space in the upper sediment column, as well as a greater volume of biogenic structures that were connected to the surface (although intra-site variability was great). Along the horizontal plane and at various depths within sediments, burrow shafts were more randomly distributed at the exposed site, compared to a more even, maximal spacing at the sheltered site. In addition to finding differences in burrow organization at two spatial scales, we found significant correlations between tomographic intensity and (1) the number of burrow shafts, (2) biogenic space and (3) organic matter content. CT-scan data, including tomographic intensity, are useful for examining and comparing biogenic structures in sediment cores.

DUNE SPIDERS OF THE NEGEV DESERT WITH NOTES ON CERBALUS PSAMMODES (HETEROPODIDAE)

ABSTRACT The community of spiders that burrow into the sand dunes of the northwestern Negev Desert was examined. Nine species were found, of which only two occurred on the unconsolidated, active dunes. The remainder occurred on the fixed bases of the dunes and the interdune depressions that were mostly covered by a biological crust. All spiders that dug their own burrows constructed vertical tunnels, which they excavated by carrying silk-sand bundles. Observations of Cerbalus psammodes (Heteropodidae) revealed it to be the Negev counterpart of the dominant heteropodid spiders occurring in the Namib dunes. Parallel characteristics include its large size, the method of burrow stabilization (but not of excavation), nocturnal activity, 1–2 m home ranges, predation on tenebrionid beetles, sexual size dimorphism, and maternal care.

SETTLING BEHAVIOR OF THE DESERT ISOPOD HEMILEPISTUS REAUMURI IN RESPONSE TO VARIATION IN SOIL MOISTURE AND OTHER ENVIRONMENTAL CUES

ABSTRACT We report the results of three studies, one observational and two manipulative, that examine the settling behavior of isopods in response to soil moisture and other cues. In a census of isopod settling patterns in twenty-five 5 × 10 m plots arranged on a 200 m2 grid, isopods settled more densely in plots with more successful old burrows from the previous season, and in plots with more shrubs. Isopod settling was not correlated with soil moisture at 10 and 30 cm depths. In a manipulative experiment carried out over two years, isopods settled more densely in 3 × 3 m outdoor pens that received 20 mm of supplemental water in February than in unwatered plots. In a second experiment, 50 mm of water was added to open plots, and two densities of artificial holes were added as well. Isopods settled more densely in plots with added water, and settled much more densely in plots with artificial holes. Water did not significantly affect isopod survival or offspring weight. Unmanipulated plots with higher dens...

Relative Importance of Burrow Sediment and Porewater to the Accumulation of Trace Metals in the Clam Amiantis umbonella

The objectives of this study were to evaluate the infaunal, facultative deposit-feeding clam Amiantis umbonella as a bioindicator of trace-metal contamination and the relative importance of clam burrow sediment and porewater to total accumulation in an urban/industrial coastal environment. Concentrations of eight trace metals (cadmium [Cd], chromium, copper, mercury [Hg], nickel, lead [Pb], vanadium, and zinc) were measured in the soft tissues of clams and in sediment and porewater from clam burrows along a 5-km transect from desalination/power plant discharges in inner Kuwait Bay. All metals had significantly greater concentrations in clams collected near the desalination/power plant discharges than from the reference site and exhibited decreasing trends with distance from the point source in clam soft tissues and burrow sediment and porewater. Concentrations of Hg (1-9ppm [dry weight]) and the highest concentrations of Pb (3ppm) and Cd (7ppm) in clams from contaminated sites in Kuwait Bay were greater than human consumption limits. Metal concentrations in clams were correlated with those in burrow sediment and porewater across all sites and at sites closest to the point source but not within the reference site. The concentrations of all metals, except Pb, in clams from the contaminated sites were more highly correlated with those in clam burrow sediment than porewater. Concentrations of Pb in clam soft tissues were more strongly correlated with those in burrow porewater than sediment. These results indicate that A. umbonella is an excellent bioindicator of trace metal contamination and that sediment is an important source of contaminant metals to this infaunal clam; however, the source of each metal must be evaluated separately.

More Evidence That the Biology of Embryogenesis Explains Metastasis

Epithelial tissue is the most common source of human cancers. When epithelial cancer cells metastasize, they sever their connections to adjacent cells, burrow through tissue and enter a blood or lymphatic vessel, survive in the circulation, exit the circulation and enter a distant organ, and then grow. As researchers …

Spatial and Temporal Oxygen Dynamics in Macrofaunal Burrows in Sediments: A Review of Analytical Tools and Observational Evidence

The availability of benthic O2 plays a crucial role in benthic microbial communities and regulates many important biogeochemical processes. Burrowing activities of macrobenthos in the sediment significantly affect O2 distribution and its spatial and temporal dynamics in burrows, followed by alterations of sediment microbiology. Consequently, numerous research groups have investigated O2 dynamics in macrofaunal burrows. The introduction of powerful tools, such as microsensors and planar optodes, to sediment analysis has greatly enhanced our ability to measure O2 dynamics in burrows at high spatial and temporal resolution with minimal disturbance of the physical structure of the sediment. In this review, we summarize recent studies of O2-concentration measurements in burrows with O2 microsensors and O2 planar optodes. This manuscript mainly focuses on the fundamentals of O2 microsensors and O2 planar optodes, and their application in the direct measurement of the spatial and temporal dynamics of O2 concentrations in burrows, which have not previously been reviewed, and will be a useful supplement to recent literature reviews on O2 dynamics in macrofaunal burrows.

HABITAT PREFERENCE OF Trapelus agilis OLIVIER IN THAR DESERT OF JAISALMER, INDIA

Preference in habitat selection by Trapelus agilis Olivier has been studied in nearby area of Amar sagar village and Garhisar Lake catchments area of Jaisalmer, Rajasthan. It has been observed that female of Agama agilis Olivier always lives in burrow. Most of the burrows remain covered by the shrubs of Capparis decidua (KER), Euphorbia (THOR), Salvadora oleoides (JAL), and Leptadaenia (KHEEP). Males never dig burrows and remain hidden under the stones, between the stones, cervices of stones and sometime in the burrow of female of agama, other lizards and rodents for short time. It has been concluded that the habitat selection and preference in Trapelus agilis depends on the local environment, sex, body size, morphology and feeding habit.

TAXONOMIC REVIEW OF CHONDRITES AFFINIS (STERNBERG, 1833) FROM CRETACEOUS-NEOGENE OFFSHORE-DEEP-SEA TETHYAN SEDIMENTS AND RECOMMENDATION FOR ITS FURTHER USE

The branched trace fossil Chondrites affinis (Sternberg, 1833), synonymised so far with C. targionii (Brongniart, 1828), has been analyzed in an exceptionally well preserved specimen from the Saraceno Formation (?Upper Cretaceous; ?Eocene-Miocene) in the southern Italy, its holotype (Prague Museum), and in other materials. It appeared that C. affinis displays a smaller burrow system/burrow width ratio and a larger size (burrow width typically over 4 mm and burrow system width over 150 mm) than C. targionii , without continuity of the latter parameters between these ichnospecies. Therefore, Chondrites affinis is considered as a separate ichnospecies, and is recommended for further use. It occurs in Upper Cretaceous to Neogene offshore, deep-sea, mostly marly sediments, and its unquestionable occurrences are known so far from the European Alpides.

Morphological studies of the appendicular skeleton of the African giant pouched rat (Cricetomys gambianus) Part (i) pectoral limb

The pelvic limb of the African giant pouched rat (Cricetomysgambianus) was studied using 12 adult rats of both sexes. Characteristics of the bones were studied by gross observation after preparation. Measurement of different segments of the Pelvic limb (articulated) was also taken. The bones of the pelvic limb were found to be generally similar in both structure and number to other rodent species that has been studied. Variation came only in the size of the bones and in the number of coccygeal bones. The ossa coxarum came (check) together through the pubic symphysis. The pelvis also presented a relatively wide obturator foramen. The femur presented three trochanters (major, minor and tertious) and fabellae on the medial and lateral condyles. The fibula runs down the length of the tibia, with an attachment proximally and fusion at the distal third thereby presenting an extensive interosseous space. The pespresented 8 tarsal and 5 metatarsal bones. Each of the metatarsal presented 3 phalanges except the first metatarsal which presented 2 phalanges. The number of bones on each pelvic limb was found to be 34 plus 19 sessamoid bones making a total number of 106 bones in the two hind limbs of this rat. Key words: African giant rat, pelvic limb, pes.

Keeping and Breeding in Captivity the Mexican Burrowing Python Loxocemus bicolor (Cope, 1861) at Moscow Zoo

The data on successful maintaining and captive breeding of rare Boidae species, the mexican burrowing python ( Loxocemus bicolor ), at Moscow Zoo is presented.

Seasonal Variation in Daily Activity Pattern in a Population of Spiny-Tailed Lizard, Uromastyx aegyptius microlepis , from the United Arab Emirates

Seasonal comparisons of the daily activity pattern of 20 Uromastyx aegyptius microlepis individuals, indicate that they are diurnal and emerge early in the morning during summer and spring (6:30 – 8:30) with average ambient temperatures between 27.5 – 28.5°C and later during winter and autumn (10:00 – 12:00) with average ambient winter temperatures of 21.6°C. More time is spent basking during winter (182 ± 80.4 min per individual) than during any other month. Den clearing activities mainly take place during autumn with 69% of the observed individuals involved in this activity then. Foraging mainly takes place during autumn (62%, 11:00 – 12:00) and spring (70%, 10:00 – 11:00) with 46.5 ± 40.5 min (autumn) and 40.4 ± 15.7 min (spring) on average per individual spent on this activity. Foraging distance from the burrow is highest during the dry summer months with an average distance of 81.9 ± 74.9m per individual observed. Retreating underground takes place with average ambient temperatures varying from 23.6 ± 0.6°C during winter to 35.7 ± 2.2°C during summer.