Numer and type of seeds introduced by footwear of travelers to Svalbard and germination success in 2008

Expanding visitation to Polar regions combined with climate warming increases the potential for alien species introduction and establishment. We quantified vascular plant propagule pressure associated with different groups of travelers to the high-Arctic archipelago of Svalbard, and evaluated the potential of introduced seeds to germinate under the most favorable average Svalbard soil temperature (10°C). We sampled the footwear of 259 travelers arriving by air to Svalbard during the summer of 2008, recording 1,019 seeds: a mean of 3.9 (±0.8) seeds per traveler. Assuming the seed influx is representative for the whole year, we estimate a yearly seed load of around 270,000 by this vector alone. Seeds of 53 species were identified from 17 families, with Poaceae having both highest diversity and number of seeds. Eight of the families identified are among those most invasive worldwide, while the majority of the species identified were non-native to Svalbard. The number of seeds was highest on footwear that had been used in forested and alpine areas in the 3 months prior to traveling to Svalbard, and increased with the amount of soil affixed to footwear. In total, 26% of the collected seeds germinated under simulated Svalbard conditions. Our results demonstrate high propagule transport through aviation to highly visited cold-climate regions and isolated islands is occurring. Alien species establishment is expected to increase with climate change, particularly in high latitude regions, making the need for regional management considerations a priority.

Sulphur geochemistry of interstitial waters and squeeze cake samples of ODP Leg 181 sites

Seventy-nine interstitial water samples from six sites (Ocean Drilling Program Sites 1119-1124) from the southwestern Pacific Ocean have been analyzed for stable isotopes of dissolved sulfate (34S), along with major and minor ions. Sulfate from the interstitial fluids (34S values between +20.7 and +57.5 vs. the Vienna-Canyon Diablo troilite standard) was enriched in 34S with respect to modern seawater (34S +20.6), indicating that differing amounts of microbial sulfate reduction took place at all investigated sites. Microbial sulfate reduction was found at all sites, the intensity depending on the availability of organic matter, which is controlled by paleosedimentation conditions (e.g., sedimentation rate and presence of turbidites). In addition, total reduced inorganic sulfur (essentially pyrite) as a product of microbial sulfate reduction was quantified in selected sediments from Site 1119.

(Tables 1,2) Viability of Poa trivialis seeds transported to Antarctica from different locations

Antarctic ecosystems are at risk from the introduction of invasive species. The first step in the process of invasion is the transportation of alien species to Antarctic in a viable state. However, the effect of long-distance human-mediated dispersal, over different time-scales, on propagule viability is not well known. We assessed the viability of Poa trivialis seeds transported to Antarctica from the UK, South Africa and Australia by ship or by ship and aircraft. Following transportation to the Antarctic Treaty area, no reduction in seed viability was found, despite journey times lasting up to 284 days and seeds experiencing temperatures as low as -1.5°C. This work confirms that human-mediated transport may overcome the dispersal barrier for some propagules, and highlights the need for effective pre-departure biosecurity measures.