A Miocene mud volcano and its plumbing system: A chaotic complex revisited (Monferrato, NW Italy)

Chaotic deposits are frequently reported in the geological literature and are commonly interpreted as olistostromes or tectonic melanges. A chaotic complex in the Cenozoic succession of Monferrato (NW Italy) consists of interbedded mud breccia and burrowed silty clays that are pierced by sheared mud breccias and embed carbonate-cemented blocks. These may be represented by microcrystalline limestones or strongly cemented matrix-supported breccias locally containing remains of chemosymbiotic organisms (lucinid bivalves). Moreover, cylindrical concretions, up to 15 cm in diameter and 1 m long, occur in the chaotic complex and crosscut bedding planes at high angles. The cement of all these lithified portions is mainly dolomite characterized by low delta(13)C values (from -10.3 to -23parts per thousand PDB) and delta(18)O values up to + 7parts per thousand PDB. The delta(13)C values testify to precipitation of carbonates induced by microbial oxidation of methane, whereas the markedly positive delta(18)C signature, ubiquitous in the cylindrical concretions, is the evidence for the presence and destabilization of gas hydrates. The studied section provides a well-exposed example of the geological record of the birth, life, and death of a mud volcano. Unsheared, soft mud breccias represent mud flows along the flanks of the volcano, whereas sheared mud breccias are the result of the injection of unconsolidated overpressured fine-grained sediments, both taking place during ``eruptive'' phases. They were followed by more quiet stages of hemipelagic sedimentation, burrowing, and CH4 seeping. The cylindrical concretions represent the first described ancient example of the chimneys observed in present-day mud-volcano settings. They are the remnants of a cold-seep plumbing network that crosscut the mud volcano edifice. The chimneys were the pathway for the expulsion toward the sea floor of gas- and sediment-charged fluids likely originated from destabilization of methane gas hydrates. The association of mud breccias and methane-derived carbonates may not be due to mass gravity flows but can be primary and, therefore, is a diagnostic criterion for recognizing chaotic deposits due to mud volcano activity in the geological record.

Blanding’s Turtle Emydoidia blandingii, 2011

Data sheet produced by the Iowa Department of Natural Resources is about different times of animals, insects, snakes, birds, fish, butterflies, etc. that can be found in Iowa.

Common Musk Turtle Sternotherus odoratus, 2011

Data sheet produced by the Iowa Department of Natural Resources is about different times of animals, insects, snakes, birds, fish, butterflies, etc. that can be found in Iowa.

Ornate Box Turtle Terrapene Ornate, 2011

Data sheet produced by the Iowa Department of Natural Resources is about different times of animals, insects, snakes, birds, fish, butterflies, etc. that can be found in Iowa.

Wood Turtle Clemmys insculpta, 2011

Data sheet produced by the Iowa Department of Natural Resources is about different times of animals, insects, snakes, birds, fish, butterflies, etc. that can be found in Iowa.

Yellow Mud Turtles Kinosternon flavescens, 2011

Data sheet produced by the Iowa Department of Natural Resources is about different times of animals, insects, snakes, birds, fish, butterflies, etc. that can be found in Iowa.

Effects of season, sex and body size on the feeding ecology of turtle-headed seasnakes (Emydocephalus annulatus) on IndoPacific inshore coral reefs

In terrestrial snakes, many cases of intraspecific shifts in dietary habits as a function of predator sex and body size are driven by gape-limitation - and hence, are most common in species that feed on relatively large prey, and exhibit a wide body-size range. Our data on seasnakes reveal an alternative mechanism for intraspecific niche partitioning, based on sex-specific seasonal anorexia induced by reproductive activities. Turtle-headed seasnakes (Emydocephalus annulatus) on coral reefs in the New Caledonian Lagoon feed entirely on the eggs of demersal-spawning fishes. DNA sequence data (cytochrome b gene) on eggs that we palpated from stomachs of 37 snakes showed that despite this ontogenetic-stage specialization, the prey come from a taxonomically diverse array of species including damselfish (41% of samples, at least 5 species), blennies (41%, 4 species) and gobies (19%, 5 species). The composition of snake diets shifted seasonally (with damselfish dominating in winter but not summer), presumably reflecting seasonality of fish reproduction. That seasonal shift affects male and female snakes differently, because reproduction is incompatible with foraging. Adult female seasnakes ceased feeding when they became heavily distended with developing embryos in late summer, and males ceased feeding while they were mate-searching in winter. The sex divergence in foraging habits may be amplified by sexual size dimorphism; females grow larger than males, and larger snakes (of both sexes) feed more on damselfish (which often lay their eggs in exposed sites) than on blennies and gobies (whose eggs are hidden within narrow crevices). Specific features of reproductive biology of coral-reef fish (seasonality and nest type) have generated intraspecific niche partitioning in these seasnakes, by mechanisms different from those that apply to terrestrial snakes.

Stable C and N isotope concentration in several tissues of the loggerhead sea turtle Caretta caretta from the western Mediterranean and dietary implications

The isotopic concentrations of carapace scutes, skin, muscle and blood of loggerhead sea turtles (Caretta caretta) from the Balearic Archipelago were analysed to investigate the pattern of variation between tissues and to assess the position of this species in the trophic webs of the Algerian Basin. Skin showed higher δ13C values than muscle or carapace scutes and these showed higher values than blood. Conversely, muscle showed higher δ15N values than skin, skin showed higher values than blood and blood showed higher values than carapace scutes. Dead and live sea turtles from the same habitat did not differ in the concentration of stable isotopes. However, some of the tissues of the turtles caught in drifting longlines in the oceanic realm showed higher δ13C values than those from the turtles caught by hand or in trammel nets over the continental shelf, although they did not differ in the δ15N. Comparison of the concentration of stable isotopes in the turtles with that of other species from several areas of the Algerian Basin revealed that they consumed planktonic prey and that the trophic level of the sea turtles was higher than that of carnivorous cnidarians but lower than that of zooplanktophagous fish and crustaceans.

Mortality rates in by-caught loggerhead turtle Caretta caretta in the Mediterranean Sea and implications for the Atlantic populations

Reliable estimates of the post-release mortality probability of marine turtles after incidental by-catch are essential for assessing the impact of longline fishing on these species.Large numbers of loggerhead turtles Caretta caretta from rookeries in the northwestern Atlantic Ocean have been by-caught annually in the southwestern Mediterranean Sea since the 1980s, but nothing is known about their post-release mortality probability under natural conditions. Pop-up archival transmitting tags were attached to 26 loggerhead turtles following incidental capture by Spanish longliners. Hooks were not removed, and 40 cm of line was left in place. The post-release mortality probability during the 90 d following release ranged from 0.308 to 0.365, and was independent of hook location. When the post-release mortality probability was combined with previously reported estimates of the mortality probability before hauling, the aggregated by-catch mortality probability ranged from 0.321 to 0.378. Assuming a total annual by-catch of 10656 loggerhead turtles by the Spanish longline fleet operating in the southwestern Mediterranean, by-catch results in 3421 to 4028 turtle deaths annually. This range is equivalent to 8.5−10.1% of the approximately 40000 turtles inhabiting the fishing grounds used by Spanish longliners, most of them from rookeries in the northwestern Atlantic. As a consequence, the accumulated mortality during the oceanic stage is expected to be larger for those loggerhead turtles of Atlantic origin that spend several years in the Mediterranean Sea than for turtles of the same cohort that remain in the Atlantic. For this reason, the Mediterranean can be considered a dead end for loggerhead turtle populations nesting in the Atlantic, although the actual demographic relevance of by-catch mortality of loggerhead turtles in the Mediterranean remains unknown.

25 years of movement monitoring on the south peak of Turtle mountain: Understanding the hazard

En 1981, le gouvernement de l'Alberta a amélioré la surveillance de la pointe sud « South Peak » de la montagne Turtle, sur la frontière sud du glissement Frank de 1903. Le programme de surveillance vise à comprendre les taux de déformation des fissures larges et profondes sur « South Peak », et à prédire une seconde avalanche rocheuse sur la montagne. Le programme de surveillance consiste à installer un complément de points statiques et de stations suivies à distance, qui sont mesurés périodiquement. Des données climatiques, microsismiques et de déformation sont recueillies automatiquement à intervalles journaliers, et sont archivées. À la fin des années 1980, le financement pour le développement du programme de surveillance a cessé et quelques installations se sont détériorées. Entre mai 2004 et septembre 2006, des lectures sur les points de surveillance encore fonctionnels ont été compilées et interprétées. De plus, les lectures prélevées auparavant ont été réinterprétées à partir des connaissances récentes sur les modèles de mouvement à court terme et les influences climatiques. Ces observations ont été comparées à des récentes observations aériennes d'un modèle digital d'élévation, provenant de « light detection and ranging (LiDAR) », et des photos de terrain, afin d'estimer plus précisément les taux, l'étendue et la distribution des mouvements pour les derniers 25 ans.