Arctic climate change poses serious threats to polar bears ( Ursus maritimus ) as reduced sea ice makes seal prey inaccessible and marine ecosystems undergo bottom‐up reorganization. Polar bears’ elongated skulls and reduced molar dentition, as compared to their sister species the grizzly bear ( Ursus arctos ), are adaptations associated with hunting seals on sea ice and a soft, lipid‐rich diet of blubber and meat. With signif...

Summary The microbial community structure of bacteria, archaea and fungi is described in an Australian native grassland soil after more than 5 years exposure to different atmospheric CO 2 concentrations ([ CO 2 ]) (ambient, + 550 ppm) and temperatures (ambient, + 2°C) under different plant functional types ( C 3 and C 4 grasses) and at two soil depths (0–5 cm and 5–10 cm). Archaeal community diversity was influenced by elevate...

Summary Since industrialization global CO 2 emissions have increased, and as a consequence oceanic pH is predicted to drop by 0.3–0.4 units before the end of the century – a process coined ‘ocean acidification’. Consequently, there is significant interest in how pH changes will affect the ocean's biota and integral processes. We investigated marine picoplankton (0.2–2 µm diameter) community response to predicted end of century...

Seasonal changes of testicular activity of the swordfish Xiphias gladius and correlations of plasma levels of testosterone (T) and 11‐ketotestosterone (11‐KT) with proliferation and apoptosis of germ cells, determined, respectively, with monoclonal antibodies against proliferating cell nuclear antigen and terminal deoxynucleotidyl transferase‐mediated d’UTP nick end labelling, are described. Three phases of the reproductive cy...

The histological analysis of eastern Atlantic bluefin tuna Thunnus thynnus ovaries caught from February to September 1999–2000, made it possible to distinguish the presence of seven oocyte developmental stages and allowed the characterization of six time‐dependent ovary maturity stages. The ovaries of mature (fork length, L F ≥ 110 cm) bluefin tuna were non‐active from August (spent period) to March (quiescent period) when the...