Metridium senile: dispersion and small scale colonization by the combined strategy of locomotion and asexual reproduction (laceration)

The process of biotope occupation by the anenome Metridium s en~l ein the absence of pelagic larvae has been investigated by an in situ monitoring experiment lasting from July 1981 to April 1982. This process is composed of several behavioral phases: dispersion of the anemones on the new substrate by h ~ g hlo comotory activity, colonization of the 'chosen' habltat by intensive asexual reproduction and finally, a stationary phase. One characteristic of the particular ecological situation in the Flensburg fjord (Western Baltic) seems to be the absence in M senile of sexual reproduction and larvae resulting in a mono- or oligoclonality of the Fjord population. This study shows that even if pelagic dispersal is missing, local dispersion and proliferation can be assured by locomotion and laceration

The seafloor from a trait perspective:A comprehensive life history dataset of soft sediment macrozoobenthos

Biological trait analysis (BTA) is a valuable tool for evaluating changes in community diversity and its link to ecosystem processes as well as environmental and anthropogenic perturbations. Trait-based analytical techniques like BTA rely on standardised datasets of species traits. However, there are currently only a limited number of datasets available for marine macrobenthos that contain trait data across multiple taxonomic groups. Here, we present an open-access dataset of 16 traits for 235 macrozoobenthic species recorded throughout multiple sampling campaigns of the Dutch Wadden Sea; a dynamic soft bottom system where humans have long played a substantial role in shaping the coastal environment. The trait categories included in this dataset cover a variety of life history strategies that are tightly linked to ecosystem functioning and the resilience of communities to (anthropogenic) perturbations and can advance our understanding of environmental changes and human impacts on the functioning of soft bottom systems

Ocean acidification and its effects upon fitness in nereidid polychaetes

In recent years there has been increasing focus on predicting the potential effects of greenhouse gas driven global warming; this has proven to be a major challenge for science. In the last decade, there has been a major shift in research with growing scientific concern over the changing ocean carbonate chemistry as a result of ever increasing anthropogenic CO₂ emissions.Major changes to the basic chemistry of seawater, such as the water pH, are likely to have substantial implications for marine life in the future (Hardege et al., 2011). Research to date has focused largely upon those organisms that require calcium carbonate to build protective shells or skeletons (Orr et al., 2005).Using semelparous polychaetes, Platynereis dumerilii and Alitta succinea, it is shown that when exposed to pH levels forecasted to occur by 2100 (pH 7.8) survival, development, reproductive output and essential behaviours e.g. feeding and predator avoidance, are negatively impacted. A. succinea show severely reduced responses to natural chemical signals with subsequent low fertilisation and larval success.The ubiquity of chemical communication in the aqueous environment indicates that chemoreception disruption can potentially have dramatic consequences. Data show that if ocean acidification continues as predicted, marine chemoreception will have to adapt rapidly with potentially profound consequences for marine life and animal interactions.It is clear from this investigation that P. dumerilii and A. succinea are not capable of acclimatisation within one lifetime. Interestingly, P. dumerilii sampled and sequenced from a naturally occurring CO₂ vent in Ischia (Naples, Italy) are genetically different from other P. dumerilii populations within Europe. Individuals appear to show signs of adaptation in behavioural trials with few significant differences between pH treatments 8.2 and 7.8. Future studies are needed to ascertain how these organisms are adapted to life in low pH waters