Bivalves are the most common macrofauna present in marine sequences spanning the end-Triassic mass extinction and document the initial ecological response to the crisis. In the west-Tethyan Kössen Basin, marine bivalves occur within distinctive low diversity episodic shell beds at the time of initial crisis and d13C minimum, and continue for 1 m (,,20 kyr) upward into the peak extinction phase ...

Local species diversity may be determined by processes operating locally, such as disturbance, predation and competition, or by regional processes, such as environmental structuring or history. Classical theory focusing on competition predicts that the species combining to form communities will be less similar to each other than they would be if they were assembled at random from a regional spe...

Numerous original and review papers have emerged over recent years concerning the natural microbiota and its interaction with the mammal host's body. This addendum supplements in short our previous review article on the role of microbiota in the host immunity paying, particular attention to such essential aspects as the composition and role of gut microbiota in viral infections as well as the i...

Organism body size has been demonstrated to be a discriminating element in shaping the response of living beings to environmental factors, thus playing a fundamental role in community structuring. Despite the importance of studies elucidating relations among communities of different size levels in ecosystems, the attempts that have been made in this sense are still very scarce and a reliable ap...

Species with markedly different sizes interact when sharing the same habitat. Unravelling mechanisms that control diversity thus requires consideration of a range of size classes. We compared patterns of diversity and community structure for meio- and macrofaunal communities sampled along a gradient of environmental stress at deep-sea hydrothermal vents on the East Pacific Rise (9° 50' N) and n...

Research so far has provided little evidence that benthic biogeochemical cycling is affected by ocean acidification under realistic climate change scenarios. We measured nutrient exchange and sediment community oxygen consumption (SCOC) rates to estimate nitrification in natural coastal permeable and fine sandy sediments under pre-phytoplankton bloom and bloom conditions. Ocean acidification, a...

Denitrification is commonly measured using in situ benthic chambers or laboratory incubations of sediment cores. These techniques are similar in principle but differ considerably in cost and practicality. Despite widespread use of both techniques, it is uncertain whether they give comparable results. We compared cores and chambers for measuring fluxes (dissolved oxygen [DO], N2, NH4, NO3 and NO...

Conventional agricultural in the Venezuelan Llanos has generated gradual soil degradation. Therefore, conservationist agriculture been proposed. According to several works, this type of management favors macrofauna. To test hypothesis, response macrofauna establishment maize crops, associated with Brachiaria dictyoneura (Bd) and Centrosema macrocarpum (Cm), was evaluated. The samples were taken...