Publications

The magnitude and distribution of net primary production (NPP) in the coastal ocean remains poorly constrained, particularly for shallow marine vegetation. Here, using a compilation of in situ annual NPP measurements across >400 sites in 72 geographic ecoregions, we provide global predictions of the productivity of seaweed habitats, which form the largest vegetated coastal biome on the planet. We find that seaweed NPP is strongly coupled to climatic variables, peaks at temperate latitudes, and is dominated by forests of large brown seaweeds. Seaweed forests exhibit exceptionally high per-area production rates (a global average of 656 and 1711 gC m-2 year-1 in the subtidal and intertidal, respectively), being up to 10 times higher than coastal phytoplankton in temperate and polar seas. Our results show that seaweed NPP is a strong driver of production in the coastal ocean and call for its integration in the oceanic carbon cycle, where it has traditionally been overlooked.

We present the elemental composition (Al, Cd, Co, Cu, Fe, Mn, Mo, Ni, V, Zn, and P) of field‐collected Trichodesmium populations. To distinguish the effects of river discharges (Amazon and Niger Rivers) and Saharan dust deposition on metal concentrations in the colonies, samples were collected both in the western (February 2001, July‐August 2001, and April‐May 2003) and eastern (May‐June 2003) basins of the North Atlantic. Metal composition (medians normalized to P) in Trichodesmium ranged from 0.011 mmol mol −1 for Co to 39 mmol mol −1 for Fe and varied over an order of magnitude among different locations. A comparison of metal ratios measured in the Trichodesmium colonies with ratios reported for the potential sources suggests that the most important sources of trace metals to the tropical and subtropical Atlantic during our sampling were the Amazon and Niger Rivers, rather than dust deposition from the Sahara.

S1. List of modelled species and individual number of records.S2. Predictive performance per modelled species.S3. Contribution of environmental predictors and apparent physiological thresholds per species.S4. Collinearity analyses between environmental predictors.S5. Predicted species richness per family and suitable habitat areas for fucoid and kelp per realm as defined by Spalding et al., (2007).S6. List of predicted species of kelp per ecoregion as defined by Spalding et al., (2007).S7. List of predicted species of fucoids per ecoregion as defined by Spalding et al., (2007).S8. Predictive layers per species and stacked as global estimates of potential species richness

Iridocytes, containing multiple stacks of proteinaceous platelets and crystalized guanine, alternating with thin cytoplasm sheets, are specialized cells that act as multilayer nano-reflectors. Convergence evolution led to their arising across a broad range of organisms, including giant clams of the Tridacninae subfamily - the only sessile and photosymbiotic organism, among animals known to possess iridocytes. Through the interference of light with their nanoscale architecture, iridocytes generate 'structural colors', which are reported to serve different purposes, from intra-species communication to camouflage. In giant clams, iridocytes were previously reported to promote a lateral - and forward scattering of photosynthetically productive radiation (PAR) into the clam tissue, as well as the back reflection of non-productive wavelengths. Hence, they are assumed to promote an increased efficiency in the use of available solar energy, while simultaneously preventing photodamage of the algal symbionts. We report the use of guanine crystals within Tridacna maxima giant clam iridocytes as a basis for photonic cooperation between the bivalve host and their photosynthetic symbionts. Our results suggest that, in addition to the previously described scattering processes, iridocytes absorb potentially damaging UV radiation (UVR) and, through successive emission, emit light at longer wavelengths, which is then absorbed by the photosynthetic pigments of the algal symbionts. Consequently, both, host and algal symbionts are sheltered from (potentially) damaging UVR, while the available solar energy within the PAR spectrum increases, thereby potentially enhancing photosynthetic and calcification rates in this large bivalve. Further, our results suggest that this photonic cooperation could be responsible for the broad repertoire of colors that characterizes the highly diverse mantle patterns found in T. maxima.

16 Symposium of Aquatic Microbial Ecology (SAME16), “From Boat to Bench”- Integrating field observation with lab experiments, 1-6 September 2019, Potsdam, Germany.-- 1 page

Abstract Graphene has shown considerable potential for sensing magnetic fields based on the Hall Effect, due to its high carrier mobility, low sheet carrier density, and low-temperature dependence. However, the cost of graphene in comparison to conventional materials has meant that its uptake in electronic manufacturing has been slow. To lower technological barriers and bring more widespread adoption of graphene Hall sensors, we are using a one-step laser scribing process that does not rely on multiple steps, toxic chemicals, and subsequent treatments. Laser-scribed graphene Hall sensors offer a linear response to magnetic fields with a normalized sensitivity of ~1.12 V/AT. They also exhibit a low constant noise voltage floor of ~ 50 nV/ $$\sqrt {{\mathrm{Hz}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mrow> <mml:mi>Hz</mml:mi> </mml:mrow> </mml:msqrt> </mml:math> for a bias current of 100 µA at room temperature, which is comparable with state-of-the-art low-noise Hall sensors. The sensors combine a high bendability, come with high robustness and operating temperatures up to 400 °C. They enable device ideas in various areas, for instance, soft robotics. As an example, we combined a laser-scribed graphene sensor with a deformable elastomer and flexible magnet to realize low-cost, compliant, and customizable tactile sensors.

Abstract Background Isolation of marine microorganisms is fundamental to gather information about their physiology, ecology and genomic content. To date, most of the bacterial isolation efforts have focused on the photic ocean leaving the deep ocean less explored. We have created a marine culture collection of heterotrophic bacteria (MARINHET) using a standard marine medium comprising a total of 1561 bacterial strains, and covering a variety of oceanographic regions from different seasons and years, from 2009 to 2015. Specifically, our marine collection includes isolates from both photic (817) and aphotic layers (744), including the oxygen minimum zone (OMZ, 362) and the bathypelagic (382), from the North Western Mediterranean Sea, the North and South Atlantic Ocean, the Indian, the Pacific, and the Arctic Oceans. With this study, we describe the taxonomy, the phylogenetic diversity and the biogeography of a fraction of the marine culturable microorganisms to enhance our knowledge about which heterotrophic marine isolates are recurrently retrieved across oceans and along all the water column. Results The partial sequencing of the 16S rRNA gene of all isolates revealed that they mainly affiliate with the classes Alphaproteobacteria (35.9%), Gammaproteobacteria (38.6%), and phylum Bacteroidetes (16.5%). In addition, Alteromonas and Erythrobacter genera were found the most common heterotrophic bacteria in the ocean growing in solid agar medium. When comparing photic, OMZ, and bathypelagic isolates sequences, a 37% of them were 100% identical. This percentage increased up to 59% when the comparison was restricted between photic and aphotic sequences (OMZ and bathypelagic together) indicating the ubiquity of some bacterial isolates along the water column. Finally, we isolated three strains related with the genus Mesonia sp. that may represent new species since their whole 16S rRNA gene shared less than 95% sequence similarity with any other culture representative. Conclusions Overall, this study highlights the relevance of culture dependent studies, with focus on marine isolated bacteria from different oceanographic regions and depths, to provide a more comprehensive view of marine microbial diversity.