Microbial metabolism directly affects trace gases in (sub) polar snowpacks

Concentrations of trace gases trapped in ice are considered to develop uniquely from direct snow/atmosphere interactions at the time of contact. This assumption relies upon limited or no biological, chemical or physical transformations occurring during transition from snow to firn to ice; a process that can take decades to complete. Here, we present the first evidence of environmental alteration due to in situ microbial metabolism of trace gases (methyl halides and dimethyl sulfide) in polar snow. We collected evidence for ongoing microbial metabolism from an Arctic and an Antarctic location during different years. Methyl iodide production in the snowpack decreased significantly after exposure to enhanced UV radiation. Our results also show large variations in the production and consumption of other methyl halides, including methyl bromide and methyl chloride, used in climate interpretations. These results suggest that this long-neglected microbial activity could constitute a potential source of error in climate history interpretations, by introducing a so far unappreciated source of bias in the quantification of atmospheric-derived trace gases trapped within the polar ice caps

Mesoscale patterns in barnacle reproduction are mediated by upwelling-driven thermal variability

18 pages, 3 tables, 7 figuresEnvironmental variables are known to regulate the reproductive output of marine intertidal organisms, but typically these variables are studied as averages and interpreted at a macroscale level. Along 200 km of coast in NW Iberia, great variability in the reproductive activity of the stalked barnacle Pollicipes pollicipes was found among 7 different locations. We found the highest number of broods reported to date in this species and suggest a more realistic method of predicting reproductive success that takes into account sea surface temperature (SST). At these same locations, we studied 13 yr of SST, thermal upwelling index (UI), ground skin temperature and chlorophyll a (chl a) satellite data, using spectral analyses to partition their temporal variability over ecologically relevant time scales. SST played the most relevant role as an environmental driver, explaining 48% of the variability in the proportion of breeding individuals (BI), but the SST-BI goodness-of-fit decreased sharply northwards. Variance-partitioning analyses indicated that cycles between 20 and 100 d in SST and UI were more important southwards, which is consistent with a latitudinal gradient in upwelling intensity and frequency along this coast. Thus, we found better biophysical coupling towards the south, where shorter fluctuation time scales in SST match the gonadal development period (around 1 mo). This pattern may explain the spatial variability in the strength of association between key environmental variables and the reproductive cycle of coastal species along their distribution rangeThis research was funded by the BiodivERsA3 2015-2016, EU HORIZON 2020 ERA-NET COFUND and the Spanish Spanish Ministerio de Economía y Competitividad under project PERCEBES (PCIN-2016-063) and the Autonomous government Xunta de Galicia-FEDER (project ED431C-2017-46). During data processing and manuscript elaboration, S.R. was funded by a PhD fellowship from the Xunta de Galicia (ED481A-2020/199) and N.W. by NASA grant 80NSSC20K0074. C.M. was supported by a contract through project PCIN-2016-063. G.M. was supported by post-doctoral contracts from projects MARISCO (CTM2014-51935-R, Spanish Ministerio de Economía y Competitividad) and PERCEBES (PCIN-2016-063). A.A. was supported by a FPU fellowship (FPU2016-04258, Spanish Ministry of Science, Innovation and Universities). J.S., P.S., B.B. and R.O. were funded by the European Maritime and Fisheries Fund (EMFF) Operational Programme for Spain (2014-2020), and the Consellería do Mar. D.V.-R. was funded by the Marie Sklodowska-Curie grant agreement No. 793627 (BEMAR, EU Horizon 2020 research and innovation programme)Peer reviewe

Diverse pathways for climate resilience in marine fishery systems

Includes authors from ICES.</p