Abstract: On the occasion of the publication of the proceedings of the Third International Biologging Science Symposium, we present a summary of the incidence of biologging in studies of animal behaviour. Studies investigating diving activity were used as a proxy to examine the use of a biologging technology. Specifically, studies referenced in the Penguiness Book, an internet-based diving database, were used to examine: (1) on which taxa of diving animals biologging is principally used; (2) which countries are the principal users and producers of biologging technology; and (3) the incidence of this approach in peer-reviewed publications. Each of these items is discussed in the light of the intrinsic limitations of biologging approaches.

Abstract: The ocean absorbs about 25% of anthropogenic CO2 emissions, which alters its chemistry. Among the changes of the carbonate system are an increase in the partial pressure of CO2 (pCO2) and a decline of pH; hence, the whole process is often referred to as 'ocean acidification'. Many microbial processes can be affected either directly or indirectly via a cascade of effects through the response of non-microbial groups and/or through changes in seawater chemistry. We briefly review the current understanding of the impact of ocean acidification on microbial diversity and processes, and highlight the gaps that need to be addressed in future research. The focus is on Bacteria, Archaea, viruses and protistan grazers but also includes total primary production of phytoplankton as well as species composition of eukaryotic phytoplankton. Some species and communities exhibit increased primary production at elevated pCO2. In contrast to their heterocystous counterparts, nitrogen fixation by non-heterocystous cyanobacteria is stimulated by elevated pCO2. The experimental data on the response of prokaryotic production to ocean acidification are not consistent. Very few other microbial processes have been investigated at environmentally relevant pH levels. The potential for microbes to adapt to ocean acidification, at either the species level by genetic change or at the community level through the replacement of sensitive species or groups by non- or less sensitive ones, is completely unknown. Consequently, the impact of ocean acidification on keystone species and microbial diversity needs to be elucidated. Most experiments used a short-term perturbation approach by using cultured organisms; few were conducted in mesocosms and none in situ. There is likely a lot to be learned from observations in areas naturally enriched with CO2, such as vents, upwelling and near-shore areas.