ALBERT

Description: 〈b〉Ecology Day〈/b〉〈br〉 Maria Amélia Martins Loução〈br〉 Web Ecol., 17, 65-67, https://doi.org/10.5194/we-17-65-2017, 2017〈br〉 Following the 150th anniversary of the science of ecology, the Portuguese Ecological Society (SPECO) proposes 14 September as Ecology Day. This day should be promoted by ecological societies to host different kinds of public and media events closely related to ecology, in a broad sense. The date, 14 September, was chosen because it was on that day Haeckel had published his 〈q〉Ökologie und Chorologie〈/q〉.

Description: 〈b〉The ecology of subindividual variability in plants: patterns, processes, and prospects〈/b〉〈br〉 Carlos M. Herrera〈br〉 Web Ecol., 17, 51-64, https://doi.org/10.5194/we-17-51-2017, 2017〈br〉 Plants produce a considerable number of structures of one kind, like leaves, flowers, fruits, and seeds, which are not identical. This paper provides an overview of current knowledge on traits that vary subindividually, the magnitude of subindividual variation, and its spatial patterning. Examples are presented on the consequences of subindividual variation for plants and consumers. Emerging links between genetics, epigenetics, subindividual variation, and population ecology are also considered.

Description: 〈b〉Could disruptive technologies also reform academia?〈/b〉〈br〉 Casparus J. Crous〈br〉 Web Ecol., 17, 47-50, https://doi.org/10.5194/we-17-47-2017, 2017〈br〉 A thriving future science community could depend on disruptive technologies to shake up outmoded academic practices.

Description: Linking diverse nutrient patterns to different water masses within anticyclonic eddies in the upwelling system off Peru Yonss Saranga José, Heiner Dietze, and Andreas Oschlies Biogeosciences, 14, 1349-1364, doi:10.5194/bg-14-1349-2017, 2017 This study aims to investigate the diverse subsurface nutrient patterns observed within anticyclonic eddies in the upwelling system off Peru. Two simulated anticyclonic eddies with opposing subsurface nitrate concentrations were analysed. The results show that diverse nutrient patterns within anticyclonic eddies are related to the presence of water mass from different origins at different depths, responding to variations in depth of the circulation strength at the edge of the eddy.

Description: Gas chromatography vs. quantum cascade laser-based N 2 O flux measurements using a novel chamber design Christian Brümmer, Bjarne Lyshede, Dirk Lempio, Jean-Pierre Delorme, Jeremy J. Rüffer, Roland Fuß, Antje M. Moffat, Miriam Hurkuck, Andreas Ibrom, Per Ambus, Heinz Flessa, and Werner L. Kutsch Biogeosciences, 14, 1365-1381, doi:10.5194/bg-14-1365-2017, 2017 We present a novel chamber design for measuring soil–atmosphere N 2 O fluxes and compare the performance of a commonly applied gas chromatography (GC) setup with laser-based (QCL) concentration detection. While GC was still a useful method for longer-term investigations, we found that closure times of 10 min and sampling every 5 s is sufficient when using a QCL system. Further, extremely low standard errors (

Description: Drivers of multi-century trends in the atmospheric CO 2 mean annual cycle in a prognostic ESM Jessica Liptak, Gretchen Keppel-Aleks, and Keith Lindsay Biogeosciences, 14, 1383-1401, doi:10.5194/bg-14-1383-2017, 2017 We analyzed the evolution of the atmospheric CO 2 mean annual cycle simulated during 1950–2300 under three scenarios designed to separate the effects of climate change, CO 2 fertilization, and land use change. CO 2 fertilization in boreal and temperate ecosystems drove mean annual cycle amplification over the NH midlatitudes during 1950–2300. Boreal and Arctic climate change drove high-latitude amplification before 2200, after which CO 2 fertilization contributed nearly equally to amplification.

Description: Viable cold-tolerant iron-reducing microorganisms in geographically diverse subglacial environments Sophie L. Nixon, Jon P. Telling, Jemma L. Wadham, and Charles S. Cockell Biogeosciences, 14, 1445-1455, doi:10.5194/bg-14-1445-2017, 2017 Despite their permanently cold and dark characteristics, subglacial environments (glacier ice–sediment interface) are known to harbour active microbial communities. However, the role of microbial iron cycling in these environments is poorly understood. Here we show that subglacial sediments harbour active iron-reducing microorganisms, and they appear to be cold-adapted. These results may have important implications for global biogeochemical iron cycling and export to marine ecosystems.

Description: Can land degradation drive differences in the C exchange of two similar semiarid ecosystems? Ana López-Ballesteros, Cecilio Oyonarte, Andrew S. Kowalski, Penélope Serrano-Ortiz, Enrique P. Sánchez-Cañete, M. Rosario Moya, and Francisco Domingo Biogeosciences Discuss., doi:10.5194/bg-2017-77,2017 Manuscript under review for BG (discussion: open, 0 comments) The concept of land degradation stems from the loss of an ecosystem's biological productivity, which in turn relies on several degradation processes, such as long-term loss of natural vegetation, depletion of soil nutrients, soil compaction or water and wind erosion, to which drylands are especially vulnerable. Currently, drylands occupy more than one third of the global terrestrial surface and will probably expand under future climate change scenarios. Drylands' key role in the global C balance has been recently demonstrated, but the effects of land degradation on C sequestration by these ecosystems needs further research. In the present study, we compare net carbon exchange, together with satellite data and meteorological, ambient and vadose zone (CO 2 , water content and temperature) variables, between two nearby (~23 km) experimental sites representing natural (i.e. site of reference) and degraded grazed semiarid grasslands located in SE Spain, via eddy covariance measurements over 6 years, with highly variable precipitation magnitude and distribution. Results show a striking difference in the annual C balances with an average release of 196 ± 40 and −23 ± 20 g C m −2 yr −1 for the degraded and natural sites, respectively. At the seasonal scale, differing patterns in net CO 2 fluxes were detected over both growing and dry seasons. As expected, during the growing seasons, greater net C uptake over longer periods was observed in the natural site, however, much greater net C release was measured in the degraded site during drought periods. We tested differences in all monitored meteorological and soil variables and found it most relevant that CO 2 at 1.50 m belowground was around 1000 ppm higher in the degraded site. Thus, we believe that subterranean ventilation of this vadose zone CO 2 , previously observed at both sites, largely drives the differences in C dynamics between them, especially during the dry season maybe due to enhanced subsoil-atmosphere interconnectivity in the degraded site. Overall, the 12 site-years of data allow direct exploration of the roles of climate and land degradation in the biological and non-biological processes that ultimately control the C sequestration capacity of semiarid ecosystems.

Description: Quantifying nutrient fluxes with a new hyporheic passive flux meter (HPFM) Julia Vanessa Kunz, Michael D. Annable, Jaehyun Cho, Wolf von Tümpling, Kirk Hatfield, Suresh Rao, Dietrich Borchardt, and Michael Rode Biogeosciences, 14, 631-649, doi:10.5194/bg-14-631-2017, 2017 The hyporheic zone, the subsurface region of streams, is a key compartment for in-stream nutrient retention. Knowledge on actual hyporheic processing rates is still limited due to methodological restrictions which are mainly related to the high local and temporal variability of subsurface flow patterns and nutrient transformation processes. We present a new device which allows quantitative assessment of hyporheic nutrient fluxes and demonstrate its advantages in an exemplary field testing.

Description: Simulating precipitation decline under a Mediterranean deciduous Oak forest: effects on isoprene seasonal emissions and predictions under climatic scenarios Anne-Cyrielle Genard-Zielinski, Christophe Boissard, Elena Ormeño, Juliette Lathière, Ilja M. Reiter, Henri Wortham, Jean-Philippe Orts, Brice Temine-Roussel, Bertrand Guenet, Svenja Bartsch, Thierry Gauquelin, and Catherine Fernandez Biogeosciences Discuss., doi:10.5194/bg-2017-17,2017 Manuscript under review for BG (discussion: open, 0 comments) From seasonal in situ observations on how a Mediterranean ecosystem responds to drought, a specific isoprene emission (ER) algorithm was developed, upon which 2100 projections (IPCC RCP2.6 and RCP8.5 scenarios) were made. ER were found to be mainly sensitive to soil water content, and poorly represented by current empirical emission model. Drought was found to aggravate thermal stress on ER, increase ER intensity and their frequency response to environmental conditions (present and future).

Description: Evaluating environmental drivers of spatial variability in free-living nematode assemblages along the Portuguese margin Lidia Lins, Frederik Leliaert, Torben Riehl, Sofia Pinto Ramalho, Eliana Alfaro Cordova, André Morgado Esteves, and Ann Vanreusel Biogeosciences, 14, 651-669, doi:10.5194/bg-14-651-2017, 2017 Anthropogenic impacts in the deep sea are regarded as high disturbers of the deep-sea bottom. This study focus in trying to understand the impact of disturbance in the ecosystem and how important functions, such as hydrodynamics and surface primary productivity, affect benthic organisms. Our results showed that high sediment variability due to hydrodynamics, and consequently disturbance, combined with high resource availability are probably the main factors promoting deep-sea species coexistence

Description: Small-scale variability in geomorphological settings influences mangrove-derived organic matter export in a tropical bay Geraldina Signa, Antonio Mazzola, James Kairo, and Salvatrice Vizzini Biogeosciences, 14, 617-629, doi:10.5194/bg-14-617-2017, 2017 Using a combined analytical approach (fatty acid and isotopic markers), we found that the different settings of the creeks flowing into Gazi Bay influenced the mangrove export to the adjacent seagrasses and coral reef. Given the major influence that organic matter exchange between habitats has on organic matter availability and consumption by fauna, the small-scale variability in mangrove export may have far-reaching consequences for local food webs and for the functioning of the whole ecosystem.

Description: Amplification of global warming through pH-dependence of DMS-production simulated with a fully coupled Earth system model Jörg Schwinger, Jerry Tjiputra, Nadine Goris, Katharina Six, Alf Kirkevåg, Øyvind Seland, Christoph Heinze, and Tatiana Ilyina Biogeosciences Discuss., doi:10.5194/bg-2017-33,2017 Manuscript under review for BG (discussion: open, 0 comments) Transient global warming under the high emission scenario RCP8.5 is amplified by up to 6 % if a pH-dependency of marine DMS-production is assumed. Importantly, this additional warming is not spatially homogeneous but shows a pronounced north-south gradient. Over the Antarctic continent, the additional warming is almost twice the global average. In the Southern Ocean we find a small DMS-climate feedback that counteracts the original reduction of DMS-production due to ocean acidification.

Description: Isoprene emission and photosynthesis during heat waves and drought in black locust Ines Bamberger, Nadine K. Ruehr, Michael Schmitt, Andreas Gast, Georg Wohlfahrt, and Almut Arneth Biogeosciences Discuss., doi:10.5194/bg-2017-32,2017 Manuscript under review for BG (discussion: open, 0 comments) We studied the effects of two weeks long summer heat waves and drought on photosynthesis and isoprene emissions in black locust trees. While photosynthesis decreased, isoprene emission increased sharply in response to heat and heat-drought stress. Comparing isoprene emissions at the same temperature, however, demonstrated that stressed trees emitted less isoprene than expected. This reveals that in order to predict isoprene emissions during heat waves, model parameters need to be re-evaluated.

Description: An assessment of geographical distribution of different plant functional types over North America simulated using the CLASS-CTEM modelling framework Rudra K. Shrestha, Vivek K. Arora, Joe R. Melton, and Laxmi Sushama Biogeosciences Discuss., doi:10.5194/bg-2017-35,2017 Manuscript under review for BG (discussion: open, 0 comments) Computer models of vegetation provide a tool to assess how future changes in climate may affect geographical distribution of vegetation. However, such models must first be assessed for their ability to reproduce present day geographical distribution of vegetation. Here, we assess the ability of one such dynamic vegetation model. We find that while the model is broadly successful in reproducing the geographical distribution of trees and grasses in North America some limitations remain.

Description: Diversity, Vol. 9, Pages 37: Dispersal, Isolation, and Interaction in the Islands of Polynesia: A Critical Review of Archaeological and Genetic Evidence Diversity doi: 10.3390/d9030037 Authors: K. Horsburgh Mark McCoy Integration of archaeology, modern genetics, and ancient DNA holds promise for the reconstruction of the human past. We examine the advances in research on the indigenous peoples of Polynesia to determine: (1) what do archaeological and genetic data (ancient and modern DNA) tell us about the origins of Polynesians; and, (2) what evidence is there for long-distance travel and contacts between Polynesians and indigenous populations of the Americas? We note that the general dispersal pattern of founding human populations in the remote islands of the Pacific and long-distance interaction spheres continue to reflect well-established models. New research suggests that the formation of an Ancestral Polynesia Culture in Western Polynesia may have involved differential patterns of dispersal followed by significant later migrations. It has also been suggested that the pause between the settlement of Western and Eastern Polynesia was centuries longer than currently thought, followed by a remarkably rapid pulse of island colonization. Long-distance travel between islands of the Pacific is currently best documented through the sourcing of artifacts, while the discovery of admixture of Native American DNA within the genome of the people from Easter Island (Rapa Nui) is strong new evidence for sustained contacts between Polynesia and the Americas.

Description: Diversity, Vol. 9, Pages 38: NGS-Based Genotyping, High-Throughput Phenotyping and Genome-Wide Association Studies Laid the Foundations for Next-Generation Breeding in Horticultural Crops Diversity doi: 10.3390/d9030038 Authors: Nunzio D’Agostino Pasquale Tripodi Demographic trends and changes to climate require a more efficient use of plant genetic resources in breeding programs. Indeed, the release of high-yielding varieties has resulted in crop genetic erosion and loss of diversity. This has produced an increased susceptibility to severe stresses and a reduction of several food quality parameters. Next generation sequencing (NGS) technologies are being increasingly used to explore “gene space” and to provide high-resolution profiling of nucleotide variation within germplasm collections. On the other hand, advances in high-throughput phenotyping are bridging the genotype-to-phenotype gap in crop selection. The combination of allelic and phenotypic data points via genome-wide association studies is facilitating the discovery of genetic loci that are associated with key agronomic traits. In this review, we provide a brief overview on the latest NGS-based and phenotyping technologies and on their role to unlocking the genetic potential of vegetable crops; then, we discuss the paradigm shift that is underway in horticultural crop breeding.

Description: Diversity, Vol. 9, Pages 33: An eDNA-Based SNP Assay for Ungulate Species and Sex Identification Diversity doi: 10.3390/d9030033 Authors: Ruth Nichols Göran Spong Many processes in wild populations are difficult to study. Genetic data, often non-invasively collected, may provide a solution to these difficulties and are increasingly used to study behavioral, demographic, ecological, and evolutionary processes. Moreover, the improved sensitivity of genetic methods now allows analyses of trace amounts of DNA left by animals in their environment (e.g., saliva, urine, epithelial cells). Environmental DNA (eDNA) thus offers new opportunities to study a range of historic and contemporary questions. Here, we present a species and sex diagnostic kit for studying browsing in a multispecies temperate ungulate assemblage. Using mitochondrial sequences deposited in Genbank, we developed four single nucleotide polymorphisms (SNPs) for identifying four temperate ungulate species. We also sequenced portions of the Amelogenin gene on the X- and Y-chromosomes and developed six SNPs (three on the X-chromosome and three on the Y-chromosome) for sex determination. We tested the SNP assays on high and low quality/quantity DNA samples.

Description: Diversity, Vol. 9, Pages 31: 16S rRNA Gene-Based Metagenomic Analysis of Ozark Cave Bacteria Diversity doi: 10.3390/d9030031 Authors: Cássia Oliveira Lauren Gunderman Cathryn Coles Jason Lochmann Megan Parks Ethan Ballard Galina Glazko Yasir Rahmatallah Alan Tackett David Thomas The microbial diversity within cave ecosystems is largely unknown. Ozark caves maintain a year-round stable temperature (12–14 °C), but most parts of the caves experience complete darkness. The lack of sunlight and geological isolation from surface-energy inputs generate nutrient-poor conditions that may limit species diversity in such environments. Although microorganisms play a crucial role in sustaining life on Earth and impacting human health, little is known about their diversity, ecology, and evolution in community structures. We used five Ozark region caves as test sites for exploring bacterial diversity and monitoring long-term biodiversity. Illumina MiSeq sequencing of five cave soil samples and a control sample revealed a total of 49 bacterial phyla, with seven major phyla: Proteobacteria, Acidobacteria, Actinobacteria, Firmicutes, Chloroflexi, Bacteroidetes, and Nitrospirae. Variation in bacterial composition was observed among the five caves studied. Sandtown Cave had the lowest richness and most divergent community composition. 16S rRNA gene-based metagenomic analysis of cave-dwelling microbial communities in the Ozark caves revealed that species abundance and diversity are vast and included ecologically, agriculturally, and economically relevant taxa.

Description: Diversity, Vol. 9, Pages 32: Venetian Local Corn (Zea mays L.) Germplasm: Disclosing the Genetic Anatomy of Old Landraces Suited for Typical Cornmeal Mush Production Diversity doi: 10.3390/d9030032 Authors: Fabio Palumbo Giulio Galla Liliam Martínez-Bello Gianni Barcaccia Due to growing concern for the genetic erosion of local varieties, four of the main corn landraces historically grown in Veneto (Italy)—Sponcio, Marano, Biancoperla and Rosso Piave—were characterized in this work. A total of 197 phenotypically representative plants collected from field populations were genotyped at 10 SSR marker loci, which were regularly distributed across the 10 genetic linkage groups and were previously characterized for high polymorphism information content (PIC), on average equal to 0.5. The population structure analysis based on this marker set revealed that 144 individuals could be assigned with strong ancestry association (>90%) to four distinct clusters, corresponding to the landraces used in this study. The remaining 53 individuals, mainly from Sponcio and Marano, showed admixed ancestry. Among all possible pairwise comparisons of individual plants, these two landraces exhibited the highest mean genetic similarity (approximately 67%), as graphically confirmed through ordination analyses based on PCoA centroids and UPGMA trees. Our findings support the hypothesis of direct gene flow between Sponcio and Marano, likely promoted by the geographical proximity of these two landraces and their overlapping cultivation areas. Conversely, consistent with its production mainly confined to the eastern area of the region, Rosso Piave scored the lowest genetic similarity (<59%) to the other three landraces and firmly grouped (with average membership of 89%) in a separate cluster, forming a molecularly distinguishable gene pool. The elite inbred B73 used as tester line scored very low estimates of genetic similarity (on average <45%) with all the landraces. Finally, although Biancoperla was represented at K = 4 by a single subgroup with individual memberships higher than 80% in almost all cases (57 of 62), when analyzed with an additional level of population structure for K = 6, it appeared to be entirely (100%) constituted by individuals with admixed ancestry. This suggests that the current population could be the result of repeated hybridization events between the two accessions currently bred in Veneto. The genetic characterization of these heritage landraces should prove very useful for monitoring and preventing further genetic erosion and genetic introgression, thus preserving their gene pools, phenotypic identities and qualitative traits for the future.

Description: Diversity, Vol. 9, Pages 35: A Comparative Analysis of Viral Richness and Viral Sharing in Cave-Roosting Bats Diversity doi: 10.3390/d9030035 Authors: Anna Willoughby Kendra Phelps PREDICT Consortium Kevin Olival Caves provide critical roosting habitats for bats globally, but are increasingly disturbed or destroyed by human activities such as tourism and extractive industries. In addition to degrading the habitats of cave-roosting bats, such activities often promote contact between humans and bats, which may have potential impacts on human health. Cave-roosting bats are hosts to diverse viruses, some of which emerged in humans with severe consequences (e.g., severe acute respiratory syndrome coronavirus and Marburg virus). Characterizing patterns of viral richness and sharing among bat species are therefore important first steps for understanding bat-virus dynamics and mitigating future bat-human spillover. Here we compile a database of bat-virus associations and bat species ecological traits, and investigate the importance of roosting behavior as a determinant of viral richness and viral sharing among bat species. We show that cave-roosting species do not host greater viral richness, when accounting for publication bias, diet, body mass, and geographic range size. Our global analyses, however, show that cave-roosting bats do exhibit a greater likelihood of viral sharing, especially those documented in the literature as co-roosting in the same cave. We highlight the importance of caves as critical foci for bat conservation, as well as ideal sites for longitudinal surveillance of bat-virus dynamics.

Description: Diversity, Vol. 9, Pages 36: In Situ Cultured Bacterial Diversity from Iron Curtain Cave, Chilliwack, British Columbia, Canada Diversity doi: 10.3390/d9030036 Authors: Soumya Ghosh Elise Paine Rob Wall Gabrielle Kam Tanna Lauriente Pet-Chompoo Sa-ngarmangkang Derrick Horne Naowarat Cheeptham The culturable bacterial diversity from Iron Curtain Cave, Chilliwack, British Columbia, Canada was examined. Sixty five bacterial isolates were successfully cultivated, purified, and identified based on 16S rRNA gene sequencing. Four distinguishable phyla, i.e., Actinobacteria (44.61%), Proteobacteria (27.69%), Firmicutes (20%) and Bacteroidetes (7.69%) were identified. Arthrobacter (21.53%) was identified as the major genus, followed by Sporosarcina (9.23%), Stenotrophomonas (9.23%), Streptomyces (6.15%), Brevundimonas (4.61%), and Crocebacterium (2.8%). Noteworthy, 12.3% of the population was recognized as unidentified bacteria. The isolates were evaluated for their potential antimicrobial activities against multidrug resistant microbial strains. Two species of the genus Streptomyces exhibited a wide range of antimicrobial activities against multidrug resistance (MDR) strains of Escherichia coli and Pseudomonas spp. along with non-resistant strains of Staphylococcus aureus and E. coli. However, all of the antimicrobial activities were only observed when the isolates were grown at 8 °C in different media. To the best of our knowledge, this is the first study conducted on the Iron Curtain Cave’s bacterial diversity, and reveals some bacterial isolates that have never been reported from a cave. Bacterial isolates identified with antimicrobial properties demonstrated that the Iron Curtain Cave can be further considered as a potential habitat for antimicrobial agents.

Description: Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the Arctic Hakase Hayashida, Nadja Steiner, Adam Monahan, Virginie Galindo, Martine Lizotte, and Maurice Levasseur Biogeosciences, 14, 3129-3155, https://doi.org/10.5194/bg-14-3129-2017, 2017 In remote regions, cloud conditions may be strongly influenced by oceanic source of dimethylsulfide (DMS) produced by plankton and bacteria. In the Arctic, sea ice provides an additional source of these aerosols. The results of this study highlight the importance of taking into account both the sea-ice sulfur cycle and ecosystem in the flux estimates of oceanic DMS near the ice margins and identify key uncertainties in processes and rates that would be better constrained by new observations.

Description: Diversity, Vol. 9, Pages 39: Diversity and Bioactivity of Marine Bacteria Associated with the Sponges Candidaspongia flabellata and Rhopaloeides odorabile from the Great Barrier Reef in Australia Diversity doi: 10.3390/d9030039 Authors: Candice Brinkmann Philip Kearns Elizabeth Evans-Illidge D. Kurtbӧke Sponges and their associated microbial communities have sparked much interest in recent decades due on the abundant production of chemically diverse metabolites that in nature serve as functional compounds required by the marine sponge host. These compounds were found to carry therapeutic importance for medicinal applications. In the presented study, 123 bacterial isolates from the culture collection of the Australian Institute of Marine Science (AIMS) previously isolated from two different sponge species, namely Candidaspongia flabellata and Rhopaloeides odorabile, originating from different locations on the Great Barrier Reef in Queensland, Australia, were thus studied for their bioactivity. The symbiotic bacterial isolates were first identified using 16S rRNA gene analysis and they were found to belong to five different dominating classes of Domain Bacteria, namely Alphaproteobacteria, Gammaproteobacteria, Flavobacteria, Bacilli and Actinobacteria. Following their taxonomical categorization, the isolates were screened for their antimicrobial activity against human pathogenic microbial reference strains: Escherichia coli (ATCC® BAA-196™), E. coli (ATCC® 13706™), E. coli (ATCC® 25922™), Klebsiella pneumoniae (ATCC® BAA-1705™), Enterococcus faecalis (ATCC® 51575™), Bacillus subtilis (ATCC® 19659™), Staphylococcus aureus (ATCC® 29247™), Candida albicans (ATCC® 10231™) and Aspergillus niger (ATCC® 16888™). Over 50% of the isolates displayed antimicrobial activity against one or more of the reference strains tested. The subset of these bioactive bacterial isolates was further investigated to identify their biosynthetic genes such as polyketide synthase (PKS) type I and non-ribosomal peptide synthetase (NRPS) genes. This was done using polymerase chain reaction (PCR) with degenerate primers that have been previously used to amplify PKS-I and NRPS genes. These specific genes have been reported to be possibly involved in bacterial secondary metabolite production. In 47% of the bacterial isolates investigated, the PKS and NRPS genes were located. Some of the bacterial isolates were found to possess both gene types, which agrees with the previous reported biosynthetic ability of certain sponge-symbiotic bacteria such as the Actinobacteria or Gammaproteobacteria to produce secondary metabolites with antimicrobial activity. All these reported activities further confirm that sponge-symbiotic bacteria hold significant bioactivity with medicinal and biotechnological importance.

Description: Diversity, Vol. 9, Pages 41: Thirty Years of Research on Crown-of-Thorns Starfish (1986–2016): Scientific Advances and Emerging Opportunities Diversity doi: 10.3390/d9040041 Authors: Morgan Pratchett Ciemon Caballes Jennifer Wilmes Samuel Matthews Camille Mellin Hugh Sweatman Lauren Nadler Jon Brodie Cassandra Thompson Jessica Hoey Arthur Bos Maria Byrne Vanessa Messmer Sofia Fortunato Carla Chen Alexander Buck Russell Babcock Sven Uthicke Research on the coral-eating crown-of-thorns starfish (CoTS) has waxed and waned over the last few decades, mostly in response to population outbreaks at specific locations. This review considers advances in our understanding of the biology and ecology of CoTS based on the resurgence of research interest, which culminated in this current special issue on the Biology, Ecology and Management of Crown-of-Thorns Starfish. More specifically, this review considers progress in addressing 41 specific research questions posed in a seminal review by P. Moran 30 years ago, as well as exploring new directions for CoTS research. Despite the plethora of research on CoTS (>1200 research articles), there are persistent knowledge gaps that constrain effective management of outbreaks. Although directly addressing some of these questions will be extremely difficult, there have been considerable advances in understanding the biology of CoTS, if not the proximate and ultimate cause(s) of outbreaks. Moving forward, researchers need to embrace new technologies and opportunities to advance our understanding of CoTS biology and behavior, focusing on key questions that will improve effectiveness of management in reducing the frequency and likelihood of outbreaks, if not preventing them altogether.

Description: Diversity, Vol. 9, Pages 40: An Overview on Marine Sponge-Symbiotic Bacteria as Unexhausted Sources for Natural Product Discovery Diversity doi: 10.3390/d9040040 Authors: Candice Brinkmann Amberlee Marker D. Kurtböke Microbial symbiotic communities of marine macro-organisms carry functional metabolic profiles different to the ones found terrestrially and within surrounding marine environments. These symbiotic bacteria have increasingly been a focus of microbiologists working in marine environments due to a wide array of reported bioactive compounds of therapeutic importance resulting in various patent registrations. Revelations of symbiont-directed host specific functions and the true nature of host-symbiont interactions, combined with metagenomic advances detecting functional gene clusters, will inevitably open new avenues for identification and discovery of novel bioactive compounds of biotechnological value from marine resources. This review article provides an overview on bioactive marine symbiotic organisms with specific emphasis placed on the sponge-associated ones and invites the international scientific community to contribute towards establishment of in-depth information of the environmental parameters defining selection and acquisition of true symbionts by the host organisms.

Description: Diversity, Vol. 9, Pages 34: Millennia-Long Co-Existence of Two Major European Whitefish (Coregonus spp.) Lineages in Switzerland Inferred from Ancient Mitochondrial DNA Diversity doi: 10.3390/d9030034 Authors: José David Granado Alonso Simone Häberle Heidemarie Hüster Plogmann Jörg Schibler Angela Schlumbaum Archaeological fish remains are an important source for reconstructing past aquatic ecosystems and ancient fishing strategies using aDNA techniques. Here, we focus on archaeological samples of European whitefish (Coregonus spp.) from Switzerland covering different time periods. Coregonus bones and scales are commonly found in archaeological assemblages, but these elements lack species specific features and thus inhibit morphological species identification. Even today, fish taxonomy is confusing and numerous species and ecotypes are recognized, and even more probably existed in the past. By targeting short fragments of the mitochondrial d-loop in 48 morphologically identified Coregonus scales and vertebrae from 10 archaeological sites in Switzerland, endogenous d-loop sequences were found in 24 samples from one Neolithic, two Roman, and four Medieval sites. Two major mtDNA clades, C and N, known from contemporary European whitefish populations were detected, suggesting co-occurrence for at least 5000 years. In the future, NGS technologies may be used to explore Coregonus or other fish species and ecotype diversity in the past to elucidate the human impact on lacustrine/limnic environments.

Description: Leveraging 35 years of forest research in the southeastern U.S. to constrain carbon cycle predictions: regional data assimilation using ecosystem experiment R. Quinn Thomas, Evan Brooks, Annika Jersild, Eric Ward, Randolph Wynne, Timothy J. Albaugh, Heather Dinon Aldridge, Harold E. Burkhart, Jean-Christophe Domec, Thomas R. Fox, Carlos A. Gonzalez-Benecke, Timothy A. Martin, Asko Noormets, David A. Sampson, and Robert O. Teskey Biogeosciences Discuss., doi:10.5194/bg-2017-46,2017 Manuscript under review for BG (discussion: open, 0 comments) Quantitative predictions of forest productivity in a changing world were improved when ecosystem manipulation experiments, including experiments that altered water and nutrient availability, were used to calibrate a mathematical forest model. When ecosystem experiments were not included in calibration, the predictions were overly sensitive to nutrient fertilization but not sensitive enough to drought in the Southeastern U.S., a region that supplies a large fraction of wood products to the world.

Description: Modelling past, present and future peatland carbon accumulation across the pan-Arctic Nitin Chaudhary, Paul A. Miller, and Benjamin Smith Biogeosciences Discuss., doi:10.5194/bg-2017-34,2017 Manuscript under review for BG (discussion: open, 0 comments) We employed an individual- and patch-based dynamic global ecosystem model to quantify long-term C accumulation rates and to assess the effects of historical and projected climate change on peatland C balances across the pan-Arctic. We found peatlands in Scandinavia, Europe, Russia and C. & E. Canada will become C source while Siberia, Far East Russia, Alaska and W. & N. Canada increase their sink capacity by the end of 21st century.

Description: The mountains of Central Asia with 70 large and small mountain ranges represent species-rich plant biodiversity hotspots. Major mountains include Saur, Tarbagatai, Dzungarian Alatau, Tien Shan, Pamir-Alai and Kopet Dag. Because a range of altitudinal belts exists, the region is characterized by high biological diversity at ecosystem, species and population levels. In addition, the contact between Asian and Mediterranean flora in Central Asia has created unique plant communities. More than 8100 plant species have been recorded for the territory of Central Asia; about 5000–6000 of them grow in the mountains. The aim of this review is to summarize all the available data from 1930 to date on alkaloid-containing plants of the Central Asian mountains. In Saur 301 of a total of 661 species, in Tarbagatai 487 out of 1195, in Dzungarian Alatau 699 out of 1080, in Tien Shan 1177 out of 3251, in Pamir-Alai 1165 out of 3422 and in Kopet Dag 438 out of 1942 species produce alkaloids. The review also tabulates the individual alkaloids which were detected in the plants from the Central Asian mountains. Quite a large number of the mountain plants produce neurotoxic and cytotoxic alkaloids, indicating that a strong chemical defense is needed under the adverse environmental conditions of these mountains with presumably high pressure from herbivores.

Description: Response of export production and dissolved oxygen concentrations in oxygen minimum zones to p CO 2 and temperature stabilization scenarios in the biogeochemical model HAMOCC 2.0 Teresa Beaty, Christoph Heinze, Taylor Hughlett, and Arne M. E. Winguth Biogeosciences, 14, 781-797, doi:10.5194/bg-14-781-2017, 2017 In this study HAMOCC2.0 is used to address how mechanisms of oxygen minimum zone (OMZ) expansion respond to changes in CO 2 radiative forcing within the model. Atmospheric p CO 2 is increased at a rate of 1 % annually until stabilized. Our study suggests that expansion in the Pacific Ocean within the model is controlled largely by changes in particulate organic carbon export (POC). The vertical expansion of the OMZs in the Atlantic and Indian oceans is linked to reduced oxygen solubility.

Description: Bayesian calibration of terrestrial ecosystem models: A study of advanced Markov chain Monte Carlo methods Dan Lu, Daniel Ricciuto, Anthony Walker, Cosmin Safta, and William Munger Biogeosciences Discuss., doi:10.5194/bg-2017-41,2017 Manuscript under review for BG (discussion: open, 0 comments) Calibration of terrestrial ecosystem models is important but challenging. Bayesian inference implemented by Markov chain Monte Carlo (MCMC) sampling provides a comprehensive framework to estimate model parameters and associated uncertainties using their posterior distributions. The effectiveness and efficiency of the method strongly depend on the MCMC algorithm used. In this study, a Differential Evolution Adaptive Metropolis (DREAM) algorithm was used to estimate posterior distributions of 21 parameters for the data assimilation linked ecosystem carbon (DALEC) model using 14 years of daily net ecosystem exchange data collected at the Harvard Forest Environmental Measurement Site eddy-flux tower. The DREAM is a multi-chain method and uses differential evolution technique for chain movement, allowing it to be efficiently applied to high-dimensional problems, and can reliably estimate heavy-tailed and multimodal distributions that are difficult for single-chain schemes using a Gaussian proposal distribution. The results were evaluated against the popular Adaptive Metropolis (AM) scheme. DREAM indicated that two parameters controlling autumn phenology have multiple modes in their posterior distributions while AM only identified one mode. The calibration of DREAM resulted in a better model fit and predictive performance compared to the AM. DREAM provides means for a good exploration of the posterior distributions of model parameters. It reduces the risk of false convergence to a local optimum and potentially improves the predictive performance of the calibrated model.

Description: Multi-frequency electrical impedance tomography as a non-invasive tool to characterize and monitor crop root systems Maximilian Weigand and Andreas Kemna Biogeosciences, 14, 921-939, doi:10.5194/bg-14-921-2017, 2017 Root systems are essential in nutrient uptake and translocation, but are difficult to characterize non-invasively with existing methods. We propose electrical impedance tomography (EIT) as a new tool for the imaging and monitoring of crop root systems. In a laboratory experiment we demonstrate the capability of the method to capture physiological responses of root systems with high spatial and temporal resolution. We conclude that EIT is a promising functional imaging technique for crop roots.

Description: The Oligotrophy to the UlTra-oligotrophy PACific Experiment (OUTPACE cruise, Feb. 18 to Apr. 3, 2015) Thierry Moutin, Andrea Doglioli, Alain De Verneil, and Sophie Bonnet Biogeosciences Discuss., doi:10.5194/bg-2017-50,2017 Manuscript under review for BG (discussion: open, 0 comments) The overall goal of OUTPACE was to obtain a successful representation of the interactions between planktonic organisms and the cycle of biogenic elements in the western tropical South Pacific Ocean across trophic and N 2 fixation gradients. The international OUTPACE cruise took place between 18 February and 3 April 2015 aboard the RV L'Atalante and involved 60 scientists. The transect covered ~ 4 000 km from the western part of the Melanesian Archipelago to the western boundary of the gyre.

Description: Daily variation in net primary production and net calcification in coral reef communities exposed to elevated pCO 2 Steeve Comeau, Peter J. Edmunds, Coulson A. Lantz, and Robert C. Carpenter Biogeosciences Discuss., doi:10.5194/bg-2017-58,2017 Manuscript under review for BG (discussion: open, 0 comments) Here we investigate how CO 2 enrichment affects in coral reef communities the relationships light–production and light–calcification. For the three communities tested, CO 2 did not affect the light–production, while calcification was lower at elevated CO 2 for all light levels. Our result indicates that CO 2 can modify the balance between net calcification and net photosynthesis of reef communities by depressing community calcification, but without affecting community photosynthesis.

Description: Ten Italian globe artichoke clones belonging to the Romanesco typology were characterized in the western coastal area of Italy (Cerveteri, Rome), using a combination of morphological (UPOV descriptors), biochemical (HPLC analysis), and molecular (AFLP, ISSR, and SSR markers) traits. Significant differences among clones were found for many of the quantitative and qualitative morphological traits. Multivariate analyses (Principal Component Analysis) showed that, of the 47 morphological descriptors assessed, four (i.e., plant height, central flower-head weight, earliness, and total flower-head weight) presented a clear grouping of the clones. Biochemical analyses showed that the clones significantly differed in the polyphenolic profiles of the flower-head, with the suggestion that some of these, such as S2, S3, S5, and S18, are more suitable for the fresh market. The clones, clustered by a UPGMA dendrogram based on 393 polymorphic AFLP and ISSR loci, showed that the clones were genetically separated from each other. This highlights the importance of characterizing, evaluating, and conserving autochthonous germplasm for future plant breeding activities. Overall, these studies resulted in the identification of two new clones, selected on the basis of flower-head morphology and earliness. These clones, named Michelangelo and Raffaello, are registered on the Italian National Register of Varieties (DM n. 6135, 3/29/2013 G.U. 91, 18 April 2013).

Description: Modeling the effects of tree species and temperature on soil's extracellular enzyme activity in 78-year-old tree plantations Xiaoqi Zhou, Shen S. J. Wang, and Chengrong Chen Biogeosciences Discuss., doi:10.5194/bg-2017-144,2017 Manuscript under review for BG (discussion: open, 0 comments) Here, we measured the responses of soil's extracellular enzyme activity to a gradient of temperatures using incubation methods in 78-year-old tree plantations. We established a new soil–enzyme–C/N model without considering plant C inputs. The modeling results help explain why exotic slash pine can grow faster, as it has longer residual soil N residence time than native hoop pine and kauri pine. This is helpful for understanding the mechanisms of soil C and N cycling by different tree species.

Description: Effects of long-term mowing on the fractions and chemical composition of soil organic matter in a semiarid grassland Jiangye Li, Qichun Zhang, Yong Li, Yimeng Liu, Jianming Xu, and Hongjie Di Biogeosciences, 14, 2685-2696, doi:10.5194/bg-14-2685-2017, 2017 (1) Solid state 13 C-NMR is a powerful tool to study the nature of soil organic carbon. (2) Moderate mowing improved the stability of the grassland soil organic carbon pool. (3) Heavy mowing decreased the stability of the grassland soil organic carbon pool. (4) Mowing once a year is the most recommended practice in the semiarid grassland. (5) Mowing twice a year should be avoided for the long term in the semiarid grassland.

Description: Carbon stocks and fluxes in the high latitudes: Using site-level data to evaluate Earth system models Sarah Chadburn, Gerhard Krinner, Philipp Porada, Annett Bartsch, Christian Beer, Luca Belelli Marchesini, Julia Boike, Bo Elberling, Thomas Friborg, Gustaf Hugelius, Margareta Johansson, Peter Kuhry, Lars Kutzbach, Moritz Langer, Magnus Lund, Frans-Jan Parmentier, Shushi Peng, Ko Van Huissteden, Tao Wang, Sebastian Westermann, Dan Zhu, and Eleanor Burke Biogeosciences Discuss., doi:10.5194/bg-2017-197,2017 Manuscript under review for BG (discussion: open, 0 comments) Earth System Models (ESMs) are our main tools to understand future climate. The Arctic is important for the future carbon cycle, particularly due to the large carbon stocks in permafrost. We evaluated the performance of the land component of three major ESMs at Arctic tundra sites, focussing on the fluxes and stocks of carbon. We show that the next steps for model improvement are to better represent the quantity of vegetation, to include mosses and to improve below-ground carbon processes.

Description: Functional diversity of microbial communities in pristine aquifers inferred by PLFA- and sequencing-based approaches Valérie F. Schwab, Martina Herrmann, Vanessa-Nina Roth, Gerd Gleixner, Robert Lehmann, Georg Pohnert, Susan Trumbore, Kirsten Küsel, and Kai U. Totsche Biogeosciences, 14, 2697-2714, https://doi.org/10.5194/bg-14-2697-2017, 2017 We used phospholipid fatty acids (PLFAs) to link specific microbial markers to the spatio-temporal changes of groundwater physico-chemistry. PLFA-based functional groups were directly supported by DNA/RNA results. O 2 resulted in increased eukaryotic biomass and abundance of nitrite-oxidizing bacteria but impeded anammox, sulphate-reducing and iron-reducing bacteria. Our study demonstrates the power of PLFA-based approaches to study the nature and activity of microorganisms in pristine aquifers.

Description: Estimating total alkalinity for coastal ocean acidification monitoring at regional to continental scales in Australian coastal waters Kimberlee Baldry, Nick Hardman-Mountford, and Jim Greenwood Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-221,2017 Manuscript under review for BG (discussion: open, 0 comments) Total alkalinity (TA) is a measure of the oceans ability to resist changes in pH. In the face of ocean acidification, having the ability to predict the distribution of TA in coastal waters may provide insight into which regions might be prone to larger pH changes. Here we test a number of commonly used models for reconstructing TA. We find that within Australian coastal waters, using salinity alone is not the best choice in this region and that models are regionally dependent.

Description: Effects of long-term mowing on the fractions and chemical composition of soil organic matter in a semiarid grassland Jiangye Li, Qichun Zhang, Yong Li, Yimeng Liu, Jianming Xu, and Hongjie Di Biogeosciences, 14, 2685-2696, https://doi.org/10.5194/bg-14-2685-2017, 2017 (1) Solid state 13 C-NMR is a powerful tool to study the nature of soil organic carbon. (2) Moderate mowing improved the stability of the grassland soil organic carbon pool. (3) Heavy mowing decreased the stability of the grassland soil organic carbon pool. (4) Mowing once a year is the most recommended practice in the semiarid grassland. (5) Mowing twice a year should be avoided for the long term in the semiarid grassland.

Description: Plant n-alkane production from litterfall altered the diversity and community structure of alkane degrading bacteria in litter layer in lowland subtropical rainforest in Taiwan Tung-Yi Huang, Bing-Mu Hsu, Wei-Chun Chao, and Cheng-Wei Fan Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-161,2017 Manuscript under review for BG (discussion: open, 0 comments) The n-alkane in litterfall and the microbial community in litter layer in different habitats of lowland subtropical rainforest were studied. We revealed that the plant vegetation of forest not only dominated the n-alkane input of habitats but also governed the diversity of microbial community of litter layer. In this study, we found that the habitat which had high n-alkane input induced a shift of relative abundance toward phylum of Actinobacteria and the growth of alkB gene contained bacteria.

Description: Modeling the effects of tree species and temperature on soil's extracellular enzyme activity in 78-year-old tree plantations Xiaoqi Zhou, Shen S. J. Wang, and Chengrong Chen Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-144,2017 Manuscript under review for BG (discussion: open, 0 comments) Here, we measured the responses of soil's extracellular enzyme activity to a gradient of temperatures using incubation methods in 78-year-old tree plantations. We established a new soil–enzyme–C/N model without considering plant C inputs. The modeling results help explain why exotic slash pine can grow faster, as it has longer residual soil N residence time than native hoop pine and kauri pine. This is helpful for understanding the mechanisms of soil C and N cycling by different tree species.

Description: Carbon stocks and fluxes in the high latitudes: Using site-level data to evaluate Earth system models Sarah Chadburn, Gerhard Krinner, Philipp Porada, Annett Bartsch, Christian Beer, Luca Belelli Marchesini, Julia Boike, Bo Elberling, Thomas Friborg, Gustaf Hugelius, Margareta Johansson, Peter Kuhry, Lars Kutzbach, Moritz Langer, Magnus Lund, Frans-Jan Parmentier, Shushi Peng, Ko Van Huissteden, Tao Wang, Sebastian Westermann, Dan Zhu, and Eleanor Burke Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-197,2017 Manuscript under review for BG (discussion: open, 0 comments) Earth System Models (ESMs) are our main tools to understand future climate. The Arctic is important for the future carbon cycle, particularly due to the large carbon stocks in permafrost. We evaluated the performance of the land component of three major ESMs at Arctic tundra sites, focussing on the fluxes and stocks of carbon. We show that the next steps for model improvement are to better represent the quantity of vegetation, to include mosses and to improve below-ground carbon processes.

Description: Technical Note: A minimally invasive experimental system for p CO 2 manipulation in plankton cultures using passive gas exchange (atmospheric carbon control simulator) Brooke A. Love, M. Brady Olson, and Tristen Wuori Biogeosciences, 14, 2675-2684, https://doi.org/10.5194/bg-14-2675-2017, 2017 This experimental system simulates future CO 2 conditions in the ocean. It mimics natural processes by allowing the CO 2 to move gently and across the surface of the water though gas exchange, making it well suited for delicate plankton. Researchers can use many small vessels, which allows tracking of the eggs from individual females, for instance. Multiple types of organisms can be grown at once, which facilitates feeding studies and other similar studies of species interactions.

Description: Assisting the Evolution of the Observing System for the Carbon Cycle through Quantitative Network Design Thomas Kaminski and Peter Julian Rayner Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-168,2017 Manuscript under review for BG (discussion: open, 0 comments) Quantitative Network Design (QND) assesses the impact of a given set of existing or hypothetical observations in a modelling framework. QND has been used to optimise in situ networks and assess the benefit from planned space missions. This paper describes recent progress and points at aspects that are not yet sufficiently addressed. It demonstrates the advantage of an integrated QND system that can simultaneously evaluate a multitude of observational data streams.

Description: The effects of carbon turnover time on terrestrial ecosystem carbon storage Yaner Yan, Xuhui Zhou, Lifeng Jiang, and Yiqi Luo Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-183,2017 Manuscript under review for BG (discussion: open, 0 comments) The effects of C turnover time on C storage have not been well quantified for previous researches, so we decomposed ecosystem C storage capacity into C turnover time and C fluxes for quantifying it. Our result showed that the resultant terrestrial C release driven by C turnover time decrease only accounted for about 13.5 % of than driven by NPP increase and the larger uncertainties in spatial variation of C turnover time than temporal changes would lead in a greater impact on ecosystem C storage.

Description: Expansion of oil palm and other cash crops causes an increase of land surface temperature in Indonesia Clifton R. Sabajo, Guerric le Maire, Tania June, Ana Meijide, Olivier Roupsard, and Alexander Knohl Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-203,2017 Manuscript under review for BG (discussion: open, 1 comment) From the analysis of MODIS and Landsat satellite data of the Jambi province in Indonesia, this first study on the effects of oil palm expansion on the surface temperature in Indonesia shows shows a local and regional warming effect caused by the expansion of oil palm plantations and other cash or tree crops between 2000 and 2015. The observed warming effects may affect ecosystem services, reduce water availabilty in the dry period and increase the vulnerability to fires in the province.

Description: Explaining CO 2 fluctuations observed in snowpacks Laura Graham and David Risk Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-172,2017 Manuscript under review for BG (discussion: open, 0 comments) Winter carbon dioxide (CO 2 ) respiration from soils is a significant and understudied component of the global carbon (C) cycle. In this study, we were able to show with a field campaign and a model how windy (advective) conditions can affect the usually slow (diffusive) transport of CO 2 from soils and out of snowpacks. This research is important to help with understanding winter CO 2 dynamics, especially for continued accurate accounting of the annual global C cycle.

Description: Optical properties of size and chemical fractions of suspended particulate matter in littoral waters of Quebec Gholamreza Mohammadpour, Jean-Pierre Gagné, Pierre Larouche, and Martin Montes Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-159,2017 Manuscript under review for BG (discussion: open, 0 comments) High mass-specific absorption coefficients of suspended particulate matter (SPM) were measured in waters having iron-enriched particles Particle chemical composition has a major influence on variability of mass-specific absorption coefficients of SPM. Conversely, size distribution mainly rules spatial changes of mass-specific scattering coefficients of SPM. Multiple optical proxies can be combined in optically complex waters for estimating changes on particle size fractions.

Description: A biophysical approach using drought stress factor for daily estimations of evapotranspiration and CO 2 uptake in high-energy water-limited environments David Helman, Itamar M. Lensky, Yagil Osem, Shani Rohatyn, Eyal Rotenberg, and Dan Yakir Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-204,2017 Manuscript under review for BG (discussion: open, 0 comments) A biophysical approach for estimating daily evapotranspiration and CO 2 uptake was tested in high-energy water-limited forest and non-forest sites in Israel after accounting for drought stress. A newly developed mobile lab system and an active Fluxnet station were used for validation. Models successfully tracked observed seasonal changes showing promise for reliable ecosystem-level flux estimations. Models were used to assess changes in water-use-efficiency due to afforestation in this region.

Description: Spatial variations in snowpack chemistry and isotopic composition of NO 3 − along a nitrogen deposition gradient in West Greenland Chris J. Curtis, Jan Kaiser, Alina Marca, N. John Anderson, Gavin Simpson, Vivienne Jones, and Erika Whiteford Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-140,2017 Manuscript under review for BG (discussion: open, 0 comments) Few studies have investigated the atmospheric deposition of nitrate in the Arctic or its impacts on Arctic ecosystems. We collected late season snowpack from 3 regions of W Greenland from the coast to the edge of the ice sheet. We found major differences in nitrate concentrations (lower at the coast) and deposition load (higher at the coast). Nitrate in snowpack undergoes losses and isotopic enrichment which are greatest in inland areas, hence deposition impacts may be greatest at the coast.

Description: The influence of episodic flooding on a pelagic ecosystem in the East China Sea Chung-Chi Chen, Gwo-Ching Gong, Wen-Chen Chou, Chih-Ching Chung, Chih-Hao Hsieh, Fuh-Kwo Shiah, and Kuo-Ping Chiang Biogeosciences, 14, 2597-2609, https://doi.org/10.5194/bg-14-2597-2017, 2017 To understand the flooding effects on a pelagic ecosystem in the East China Sea (ECS), a variety of variables were measured in 2009 (non-flood) and 2010 (flood). In 2010, the organic carbon consumption was higher than in 2009; this could be attributed to the vigorous plankton activities observed in low-salinity areas. A huge amount of f  CO 2 was also drawn down in the flood. This flood effect might become more pronounced as extreme rainfall events increase dramatically throughout the world.

Description: Limited protection of macro-aggregate-occluded organic carbon in Siberian steppe soils Norbert Bischoff, Robert Mikutta, Olga Shibistova, Alexander Puzanov, Marina Silanteva, Anna Grebennikova, Roland Fuß, and Georg Guggenberger Biogeosciences, 14, 2627-2640, https://doi.org/10.5194/bg-14-2627-2017, 2017 This study set out to determine the quantity of organic carbon (OC) which is protected from microbial decomposition in macro-aggregates of Siberian steppe soils under different land use. Our results imply that the quantity of macro-aggregate protected OC is smaller than in similar steppe ecosystems like the North American prairies. We conclude that the tillage-induced breakdown of macro-aggregates after grassland to arable land conversion has not reduced the OC contents in the studied soils.

Description: Anatomical structure overrides temperature controls on magnesium uptake -- calcification in the Arctic/subarctic coralline algae Leptophytum laeve and Kvaleya epilaeve (Rhodophyta; Corallinales) Merinda C. Nash and Walter Adey Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-180,2017 Manuscript under review for BG (discussion: open, 0 comments) Past seawater temperatures can be reconstructed using magnesium / calcium ratios of biogenic carbonates. As temperature increases, so does magnesium. Here we show that for these arctic/subarctic coralline algae, anatomy is the first control on Mg / Ca, not temperature. When using coralline algae for temperature reconstruction, it is first necessary to check for anatomical influences on Mg / Ca.

Description: Flooding-related increases in CO 2 and N 2 O emissions from a temperate coastal grassland ecosystem Amanuel W. Gebremichael, Bruce Osborne, and Patrick Orr Biogeosciences, 14, 2611-2626, https://doi.org/10.5194/bg-14-2611-2017, 2017 Given their increasing trend in Europe, an understanding of the role that flooding events play in carbon (C) and nitrogen (N) cycling and greenhouse gas (GHG) emissions will be important for improved assessments of local and regional GHG budgets. This study presents the results of an analysis of the CO 2 and N 2 O fluxes from a coastal grassland ecosystem affected by episodic flooding that was of either a relatively short (SFS) or long (LFS) duration. Compared to the SFS, the annual CO 2 and N 2 O emissions were 1.4 and 1.3 times higher at the LFS, respectively. Mean CO 2 emissions during the period of standing water were 144 ± 18.18 and 111 ± 9.51 mg CO 2 –C m −2  h −1 , respectively, for the LFS and SFS sites. During the growing season, when there was no standing water, the CO 2 emissions were significantly larger from the LFS (244 ± 24.88 mg CO 2 –C m −2  h −1 ) than the SFS (183 ± 14.90 mg CO 2 –C m −2  h −1 ). Fluxes of N 2 O ranged from −0.37 to 0.65 mg N 2 O–N m −2  h −1 at the LFS and from −0.50 to 0.55 mg N 2 O–N m −2  h −1 at the SFS, with the larger emissions associated with the presence of standing water at the LFS but during the growing season at the SFS. Overall, soil temperature and moisture were identified as the main drivers of the seasonal changes in CO 2 fluxes, but neither adequately explained the variations in N 2 O fluxes. Analysis of total C, N, microbial biomass and Q 10 values indicated that the higher CO 2 emissions from the LFS were linked to the flooding-associated influx of nutrients and alterations in soil microbial populations. These results demonstrate that annual CO 2 and N 2 O emissions can be higher in longer-term flooded sites that receive significant amounts of nutrients, although this may depend on the restriction of diffusional limitations due to the presence of standing water to periods of the year when the potential for gaseous emissions are low.

Description: 20th century changes in carbon isotopes and water-use efficiency: tree-ring-based evaluation of the CLM4.5 and LPX-Bern models Kathrin M. Keller, Sebastian Lienert, Anil Bozbiyik, Thomas F. Stocker, Olga V. Churakova (Sidorova), David C. Frank, Stefan Klesse, Charles D. Koven, Markus Leuenberger, William J. Riley, Matthias Saurer, Rolf Siegwolf, Rosemarie B. Weigt, and Fortunat Joos Biogeosciences, 14, 2641-2673, https://doi.org/10.5194/bg-14-2641-2017, 2017 Measurements of the stable carbon isotope ratio ( δ 13 C) on annual tree rings offer new opportunities to evaluate mechanisms of variations in photosynthesis and stomatal conductance under changing CO 2 and climate conditions, especially in conjunction with process-based biogeochemical model simulations. The isotopic discrimination is indicative of the ratio between the CO 2 partial pressure in the intercellular cavities and the atmosphere ( c i ∕ c a ) and of the ratio of assimilation to stomatal conductance, termed intrinsic water-use efficiency (iWUE). We performed isotope-enabled simulations over the industrial period with the land biosphere module (CLM4.5) of the Community Earth System Model and the Land Surface Processes and Exchanges (LPX-Bern) dynamic global vegetation model. Results for C3 tree species show good agreement with a global compilation of δ 13 C measurements on leaves, though modeled 13 C discrimination by C3 trees is smaller in arid regions than measured. A compilation of 76 tree-ring records, mainly from Europe, boreal Asia, and western North America, suggests on average small 20th century changes in isotopic discrimination and in c i ∕ c a and an increase in iWUE of about 27 % since 1900. LPX-Bern results match these century-scale reconstructions, supporting the idea that the physiology of stomata has evolved to optimize trade-offs between carbon gain by assimilation and water loss by transpiration. In contrast, CLM4.5 simulates an increase in discrimination and in turn a change in iWUE that is almost twice as large as that revealed by the tree-ring data. Factorial simulations show that these changes are mainly in response to rising atmospheric CO 2 . The results suggest that the downregulation of c i ∕ c a and of photosynthesis by nitrogen limitation is possibly too strong in the standard setup of CLM4.5 or that there may be problems associated with the implementation of conductance, assimilation, and related adjustment processes on long-term environmental changes.

Description: Land-use and land-cover change carbon emissions between 1901 and 2012 constrained by biomass observations Wei Li, Philippe Ciais, Shushi Peng, Chao Yue, Yilong Wang, Martin Thurner, Sassan S. Saatchi, Almut Arneth, Valerio Avitabile, Nuno Carvalhais, Anna B. Harper, Etsushi Kato, Charles Koven, Yi Y. Liu, Julia E. M. S. Nabel, Yude Pan, Julia Pongratz, Benjamin Poulter, Thomas A. M. Pugh, Maurizio Santoro, Stephen Sitch, Benjamin D. Stocker, Nicolas Viovy, Andy Wiltshire, Rasoul Yousefpour, and Sönke Zaehle Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-186,2017 Manuscript under review for BG (discussion: open, 0 comments) We used several observation-based biomass datasets to constrain the historical land use change carbon emissions simulated by models. Compared to the large range of the original modelled emissions (from 94 to 273 Pg C), the observationally constrained global cumulative emission estimate is of 155 ± 50 (1-σ Gaussian error) Pg C from 1901 to 2012. Our approach reduces the uncertainty and can be also applied to evaluate the LULCC impact of land-based climate mitigation policies.

Description: A zero power warming chamber for investigating plant responses to rising temperature Keith F. Lewin, Andrew McMahon, Kim S. Ely, Shawn P. Serbin, and Alistair Rogers Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-208,2017 Manuscript under review for BG (discussion: open, 0 comments) Experiments that manipulate the temperature of plants and ecosystems are used to improve understanding of how they will respond to climate change. In logistically challenging locations passive warming using solar energy is the the only viable option for warming experiments. Unfortunately current passive warming approaches can only raise air temperature by about 1.5 °C. We have developed a novel approach that doubles the warming possible using solar energy and requires no power.

Description: Temporal variability of chlorophyll distribution in the Gulf of Mexico: bio-optical data from profiling floats Orens Pasqueron de Fommervault, Paula Perez-Brunius, Pierre Damien, and Julio Sheinbaum Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-201,2017 Manuscript under review for BG (discussion: open, 0 comments) Chlorophyll concentration is a key oceanic biogeochemical variable. In the Gulf of Mexico (GOM), its distribution, which is mainly obtained from satellite surface observations and scarce in situ experiments, is still poorly understood. In 2011–2012, eight profiling floats equipped with biogeochemical sensors were deployed for the first time in the GOM and generated an unprecedented dataset that significantly increased the number of chlorophyll vertical distribution measurements in the region. The analysis of these data, once calibrated, permits us to reconsider the spatial and temporal variability of the chlorophyll concentration in the water column. At a seasonal scale, results confirm the surface signal seen by satellites, presenting maximum concentrations in winter and low values in summer. It is shown that the deepening of the mixed layer depth is the primary factor triggering the chlorophyll surface increase in winter. In the GOM, current belief is that this surface increase corresponds to a biomass increase. However, the present dataset reveals a vertically integrated content of chlorophyll which remains constant throughout the year, suggesting that the surface increase results from a vertical redistribution of subsurface chlorophyll or photoacclimation processes, rather than a net increase of primary productivity. One plausible explanation for this is the decoupling between the mixed layer depth and the deep nutrient reservoir since mixed layer depth only reaches the nitracline in sporadic events in the observations. Float measurements also provide evidence that the depth and the magnitude of the deep chlorophyll maximum is strongly controlled by the mesoscale variability, with higher chlorophyll biomass generally observed in cyclones rather than anticyclones.

Description: Modelling biogeochemical processes in sediments from the north western Adriatic Sea: response to enhanced POC fluxes Daniele Brigolin, Christophe Rabouille, Bruno Bombled, Silvia Colla, Salvatrice Vizzini, Roberto Pastres, and Fabio Pranovi Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-206,2017 Manuscript under review for BG (discussion: open, 0 comments) This work presents the result of a study carried out in the north-western Adriatic Sea, by combining two different types of biogeochemical models with field sampling efforts. A longline mussel farm was taken as a local source of perturbation to the natural POC downward flux. This flux was first quantified by means of a pelagic model of POC deposition coupled to sediment traps data, and its effects on sediment bioirrigation capacity and OM degradation pathways were investigated by constraining an early diagenesis model, linked to new data in sediment porewaters. The measurements were performed at stations located inside and outside the area affected by mussel farm deposition. Model-predicted POC fluxes showed marked spatial and temporal variability, which were mostly associated with the dynamics of the farming cycle. Sediment traps data at the two sampled stations (in and out of the mussel farm) showed average POC background flux of 20.0–24.2 mmol C m −2  d −1 . The difference of OC fluxes between the two stations was in agreement with model results, ranging between 3.3 and 14.2 mmol C m −2  d −1 , and primarily associated with mussel physiological conditions. Although restricted, these changes in POC fluxes induced visible effects on sediment biogeochemistry. Observed oxygen microprofiles presented a 50 % decrease in oxygen penetration depth (from 2.3 to 1.4 mm), accompanied by an increase in the O 2 influx at the station below the mussel farm (19–31 versus 10–12 mmol O 2  m −2  d −1 ) characterized by higher POC flux. DIC and NH 4 + concentrations had similar behavior, with a more evident effect of bioirrigation underneath the farm. This was confirmed through constraining the early diagenesis model, which calibration leads to an estimation of enhanced and shallower bioirrigation underneath the farm: bioirrigation rates of 40 y −1 and irrigation depth of 15 cm were estimated inside the shellfish deposition footprint versus 20 y −1 and 20 cm outside. These findings were confirmed by independent data on macrofauna composition collected at the study site. Early diagenesis model results indicated a larger organic matter mineralization below the mussel farm (11.1 versus 18.7 mmol m −2  d −1 ), characterized by similar proportions between oxic and anoxic degradation pathways at the two stations, with an increase in the absolute values of oxygen consumed by OM degradation and reduced substances re-oxidation underneath the mussel farm.

Description: Ocean acidification changes the structure of an Antarctic coastal protistan community Alyce M. Hancock, Andrew T. Davidson, John McKinlay, Andrew McMinn, Kai Schulz, and Rick L. van den Enden Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-224,2017 Manuscript under review for BG (discussion: open, 0 comments) Absorption of carbon dioxide (CO 2 ) realised by humans is decreasing the ocean pH (ocean acidification). Single celled organisms (microbes) support the Antarctic ecosystem, yet little is known about their sensitivity to ocean acidification. This study shows a shift in a natural Antarctic microbial community, with CO 2 levels exceeding 634 μatm changing the community composition and favouring small cells. This would have significant flow-effects for Antarctic food webs and elemental cycles.

Description: Soil nitrogen oxide fluxes from lowland forests converted to smallholder rubber and oil palm plantations in Sumatra, Indonesia Evelyn Hassler, Marife D. Corre, Syahrul Kurniawan, and Edzo Veldkamp Biogeosciences, 14, 2781-2798, https://doi.org/10.5194/bg-14-2781-2017, 2017 We measured the soil N-oxide gases, N 2 O and NO in four land uses of Jambi, Sumatra, Indonesia. We aimed to assess the impact of forest conversion to rubber and oil palm plantations on these N-oxide gases. We found that there were no differences in soil N-oxide fluxes among land uses. However, soil N-oxide fluxes increased following N-fertilizer application in oil palm plantations. We estimated an annual soil N-oxide emission of 361 t N yr −1 from N fertilization for the Jambi province.

Description: Continuous fluorescence-based monitoring of seawater pH in a temperate estuary John W. Runcie, Christian Krause, Sergio A. Torres Gabarda, and Maria Byrne Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-222,2017 Manuscript under review for BG (discussion: open, 0 comments) pH in coastal waters can be highly variable. A means to measure this variation is needed. A fully autonomous submersible fluorescence-based pH monitoring device incorporating additional sensors for temperature and salinity was deployed in or adjacent to a shallow estuary for week-long intervals. Results and calculated aragonite/calcite saturation values are presented. The device is well suited to continuous flow-through or standalone measurements with a precision of at least 0.022 pH units.

Description: Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard) Petr Kotas, Hana Šantrůčková, Josef Elster, and Eva Kaštovská Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-184,2017 Manuscript under review for BG (discussion: open, 0 comments) The soil microbial properties were investigated along altitudinal gradients in the Arctic. The significant shifts in composition, size and activity of microbial communities were mainly controlled by vegetation distribution (through its effect on edaphic conditions) and by bedrock chemistry. The upward migration of vegetation due to global warming will diminish the variability of microbial properties along the altitudinal gradients and could have negative implications for microbial diversity.

Description: Influence of infrastructure on water quality and greenhouse gas dynamics in urban streams Rose M. Smith, Sujay S. Kaushal, Jake J. Beaulieu, Michael J. Pennino, and Claire Welty Biogeosciences, 14, 2831-2849, https://doi.org/10.5194/bg-14-2831-2017, 2017 Urban streams receive excess nitrogen from numerous sources. We hypothesized that variations in carbon availability and subsurface infrastructure influence emissions of N 2 O and other greenhouse gases (CH 4 and CO 2 ) as excess N is utilized by microbes. We sampled eight streams draining four categories of stormwater and sanitary infrastructure. Dissolved nitrogen concentration was the strongest predictor of CO 2 and N 2 O concentrations, while C : N ratio was the strongest predictor of CH 4 in streams.

Description: Sand quarry wetlands provide high-quality habitat for native amphibians Michael Sievers Web Ecol., 17, 19-27, https://doi.org/10.5194/we-17-19-2017, 2017 Artificial wetlands are becoming critical habitats as natural wetlands continue to be degraded and destroyed. I surveyed quarry wetlands to assess how they provide habitat for frogs and the factors driving patterns. Quarry wetlands consistently harboured more species and healthier individuals than reference wetlands. We need to encourage wildlife utilisation of quarry wetlands, and the methods outlined here provide a powerful, yet simple, tool to assess the overall health of artificial wetlands.

Description: The effects of marine protected areas over time and species' dispersal potential: a quantitative conservation conflict attempt Aristides Moustakas Web Ecol., 16, 113-122, https://doi.org/10.5194/we-16-113-2016, 2016 Protected areas are an important conservation measure. However, there are controversial findings regarding whether closed areas are beneficial for species and habitat conservation as well as for harvesting. Species dispersal is acknowledged as a key factor for the design and impacts of protected areas. A series of agent-based models using random diffusion to model fish dispersal were run before and after habitat protection. All results were normalized without the protected habitat in each scenario to detect the relative difference after protecting an area, all else being equal. Model outputs were compared with published data regarding the impacts over time of MPAs on fish biomass. In addition, data on species' dispersal potential in terms of kilometres per year are compared with model outputs. Results show that fish landings of species with short dispersal rates will take longer to reach the levels from before the Marine Protected Areas (MPAs) were established than landings of species with long dispersal rates. Further, the establishment of an MPA generates a higher relative population source within the MPA for species with low dispersal abilities than for species with high dispersal abilities. Results derived here show that there exists a feasible win-win scenario that maximizes both fish biomass and fish catches.

Description: Comparison of heavy-metal bioaccumulation properties in Pinus sp. and Quercus sp. in selected European Cu deposits Peter Andráš, Ingrid Turisová, Giuseppe Buccheri, João Manuel Xavier de Matos, and Vojtech Dirner Web Ecol., 16, 81-87, https://doi.org/10.5194/we-16-81-2016, 2016 This research compares the heavy-metal contents in Pinus pinaster, P. sylvestris, Quercus robur, and Q. rotundifolium in contaminated Cu deposits from Italy (Libiola, Caporciano), Portugal (São Domingos), and Slovakia (Ľubietová). The bioavailability of the heavy metals is not pH controlled, but high Ca and Mg contents in soil inhibit the metal incorporation to the plants. The plants are excluders (bioconcentration factor 〈 1), so they are suitable only for phytostabilization.

Description: Vulnerability, resilience, hazard, risk, damage, and loss: a socio-ecological framework for natural disaster analysis Marco Modica and Roberto Zoboli Web Ecol., 16, 59-62, https://doi.org/10.5194/we-16-59-2016, 2016 Evaluating socio-economic losses due to natural disasters is challenging because of the complexity of the social and ecological systems affected (also under pressure from the expected effects of climate change). This paper suggests a general framework encompassing all the important concepts needed in the assessment of natural disasters. In particular, we propose a set of relationships among vulnerability, resilience, hazard, risk, damage, and loss which can guide socio-economic assessment.

Description: Biodiversity offsetting in England: governance rescaling, socio-spatial injustices, and the neoliberalization of nature Evangelia Apostolopoulou Web Ecol., 16, 67-71, https://doi.org/10.5194/we-16-67-2016, 2016 I use primary empirical data obtained through interviews in case studies around England to explore the neoliberal character of biodiversity offsetting, its interrelationship with governance rescaling, and the way the latter influences the distribution of offsetting’s costs and benefits. My results show that biodiversity offsetting in England has been a reactionary neoliberal policy characterized by important deficits from an environmental and socio-spatial justice perspective.

Description: Greening offshore wind with the Smart Wind Chart evaluation tool Takvor Soukissian, Sofia Reizopoulou, Paraskevi Drakopoulou, Panagiotis Axaopoulos, Flora Karathanasi, Simona Fraschetti, Laura Bray, Federica Foglini, Anastasios Papadopoulos, Francesco De Leo, Chara Kyriakidou, Evangelos Voukouvalas, Evangelos Papathanassiou, and Ferdinando Boero Web Ecol., 16, 73-80, https://doi.org/10.5194/we-16-73-2016, 2016 The identification of potential zones for offshore wind farm development is a delicate and multifaceted procedure. For this aim, a holistic approach has been adopted integrating technical and environmental criteria related to the offshore wind energy exploitation. The integration is made feasible through the Smart Wind Chart that aims to maintain and secure the sustainable blue growth in the Mediterranean Sea through the support of offshore wind energy projects and marine habitat conservation.

Description: Potential climate-induced distributions of Lophodermium needle cast across central Siberia in the 21 century N. M. Tchebakova, N. A. Kuzmina, E. I. Parfenova, V. A. Senashova, and S. R. Kuzmin Web Ecol., 16, 37-39, https://doi.org/10.5194/we-16-37-2016, 2016 Lophodermium needle cast is a common disease in the genus Pinus. Our analyses relating needle cast to climate in central Siberia showed that the disease depended most on precipitation and summer temperatures were important to trigger the disease in wetter years. In a warming climate needle cast outbreaks would have damaged the largest forest areas by 2020. In 2080 the outbreak progression would slow down because the Scots pine (the host tree) shift would be halted by the slow permafrost retreat.

Description: Human population density and tenebrionid richness covary in Mediterranean islands Simone Fattorini and Giovanni Strona Web Ecol., 16, 63-65, https://doi.org/10.5194/we-16-63-2016, 2016 An unexpected high biodiversity can be found even in densely inhabited areas, possibly as a result of a tendency of human settlements to be located in sites particularly favourable also for other organisms. We studied the relationship between human density and tenebrionid beetle richness in Italian islands. Tenebrionid richness increased with human population density. This suggests that islands that are more hospitable to humans are also those that can be more favourable for tenebrionids.

Description: Using niche models of indicator species to predict the distribution of xerophytic shrub dune communities R. M. Chefaoui, S. Chozas, O. Correia, A. M. C. Santos, and J. Hortal Web Ecol., 16, 47-49, https://doi.org/10.5194/we-16-47-2016, 2016 Dune plant assemblages are affected by severe conditions, which makes them excellent models for studying the effects of species interactions and environmental conditions on community structure. We evaluate the relationship between the structure of dune communities, local environmental conditions and the suitability of climatic conditions for their characteristic species. Using data from an extensive survey of xerophytic inland sand dune scrub communities from Portugal – one of the most threatened habitat types of Europe – we identify the main gradients of vegetation composition, the different types of communities and their indicator shrub species. Then, we model the geographical responses of these species to the environment. Soil organic matter, isothermality and the habitat suitability for Stauracanthus genistoides defined the distribution of three shrub communities in the study area.

Description: Impacts of land-use intensification on litter decomposition in western Kenya G. H. Kagezi, M. Kaib, P. Nyeko, C. Bakuneeta, M. Schädler, J. Stadler, and R. Brandl Web Ecol., 16, 51-58, https://doi.org/10.5194/we-16-51-2016, 2016 Tropical forests are faced with a loss of forest cover with effects on ecosystem processes. We quantified decomposition within forest fragments and sites affected by increasing levels of agricultural land-use intensity. Mass loss increased with the area of forest fragments and decreased with land-use intensification. Fragmentation has negative effects on litter decomposition. However, the magnitude of this negative effect was not as large as expected.

Description: Cyanobacterial carbon concentrating mechanisms facilitate sustained CO 2 depletion in eutrophic lakes Ana M. Morales-Williams, Alan D. Wanamaker Jr., and John A. Downing Biogeosciences, 14, 2865-2875, https://doi.org/10.5194/bg-14-2865-2017, 2017 Our study investigated the mechanisms sustaining cyanobacteria blooms when CO 2 is depleted in lake surface waters. We found that when lake CO 2 concentrations drop below those of the atmosphere, cyanobacteria switch on carbon concentrating mechanisms (CCMs), allowing them to actively take up bicarbonate. This may provide bloom-forming cyanobacteria with a competitive advantage over other algae. These results provide insight into the timing and duration of blooms in high-nutrient lakes.

Description: Biogeochemical versus ecological consequences of modeled ocean physics Sophie Clayton, Stephanie Dutkiewicz, Oliver Jahn, Christopher Hill, Patrick Heimbach, and Michael J. Follows Biogeosciences, 14, 2877-2889, https://doi.org/10.5194/bg-14-2877-2017, 2017 We present a systematic study of the differences generated by coupling the same ecological–biogeochemical model to a 1°, coarse-resolution, and 1∕6°, eddy-permitting, global ocean circulation model to (a) biogeochemistry (e.g., primary production) and (b) phytoplankton community structure. Surprisingly, we find that the modeled phytoplankton community is largely unchanged, with the same phenotypes dominating in both cases. Conversely, there are large regional and seasonal variations in primary production, phytoplankton and zooplankton biomass. In the subtropics, mixed layer depths (MLDs) are, on average, deeper in the eddy-permitting model, resulting in higher nutrient supply driving increases in primary production and phytoplankton biomass. In the higher latitudes, differences in winter mixed layer depths, the timing of the onset of the spring bloom and vertical nutrient supply result in lower primary production in the eddy-permitting model. Counterintuitively, this does not drive a decrease in phytoplankton biomass but results in lower zooplankton biomass. We explain these similarities and differences in the model using the framework of resource competition theory, and find that they are the consequence of changes in the regional and seasonal nutrient supply and light environment, mediated by differences in the modeled mixed layer depths. Although previous work has suggested that complex models may respond chaotically and unpredictably to changes in forcing, we find that our model responds in a predictable way to different ocean circulation forcing, despite its complexity. The use of frameworks, such as resource competition theory, provides a tractable way to explore the differences and similarities that occur. As this model has many similarities to other widely used biogeochemical models that also resolve multiple phytoplankton phenotypes, this study provides important insights into how the results of running these models under different physical conditions might be more easily understood.

Description: Spatial variations in snowpack chemistry and isotopic composition of NO 3 − along a nitrogen deposition gradient in West Greenland Chris J. Curtis, Jan Kaiser, Alina Marca, N. John Anderson, Gavin Simpson, Vivienne Jones, and Erika Whiteford Biogeosciences Discuss., doi:10.5194/bg-2017-140,2017 Manuscript under review for BG (discussion: open, 0 comments) Few studies have investigated the atmospheric deposition of nitrate in the Arctic or its impacts on Arctic ecosystems. We collected late season snowpack from 3 regions of W Greenland from the coast to the edge of the ice sheet. We found major differences in nitrate concentrations (lower at the coast) and deposition load (higher at the coast). Nitrate in snowpack undergoes losses and isotopic enrichment which are greatest in inland areas, hence deposition impacts may be greatest at the coast.

Description: Plant functional types, nutrients and hydrology drive carbon cycling along a transect in an anthropogenically altered Canadian peatland complex Sina Berger, Leandra Praetzel, Marie Goebel, Christian Blodau, and Klaus-Holger Knorr Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-191,2017 Manuscript under review for BG (discussion: open, 0 comments) Peatlands play an important role in global carbon cycling, however, the response of peatland carbon fluxes to anthropogenically changed hydrologic conditions and long-term infiltration of nutrients is still understudied. Along a transect of 4 study sites, spanning from largely pristine to strongly altered conditions within the Wylde Lake peatland complex in Ontario (Canada), we monitored carbon dioxide (CO 2 ) and methane (CH 4 ) fluxes at the soil/atmosphere interface and DIC and CH 4 concentrations in the peat profiles from April 2014 through September 2015. Moreover, we applied δ 13 C-CH 4 and δ 13 C-CO 2 stable isotope abundance analyses to examine CH 4 and CO 2 production and consumption as well as the dominant CH 4 emission pathways during the growing season of 2015. We found that a graminoid-moss dominated site, which was exposed to wet conditions and long-term infiltration of nutrients, was a great sink of CO 2 (2260 ± 480 g CO 2  m −2 ) but a great source of CH 4 (61.4 ± 32 g CH 4  m −2 ). Comparably low δ 13 C-CH 4 signatures (−62.30 ± 5.54 ‰) indicated only low mitigation of CH 4 emission by methanotrophic activity here. On the contrary, a shrub dominated site, which has been subjected to similarly high moisture conditions and loads of nutrients, was a much weaker sink of CO 2 (1093 ± 794 g CO 2  m −2 ) as compared with all other sites. The shrub dominated site featured notably low DIC concentrations in the peat as well as comparably 13 C enriched CH 4 (δ 13 C-CH 4 : −57.81 ± 7.03 ‰) and depleted CO 2 (δ 13 C-CO 2 : −15.85 ± 3.61 ‰) in a more decomposed and surficial aerated peat, suggesting a higher share of CH 4 oxidation. Plant mediated transport was the prevailing methane emission pathway throughout the summer of 2015 among all sites, even where graminoids covered only 10 % of the area. Our study provides insight into the accelerated carbon cycling of a strongly altered peatland and our results supported earlier findings, that strongly altered, shrub dominated peatlands may turn into weak carbon sinks or even sources, while a graminoid-moss dominance may maintain the peatland's carbon storage function.

Description: Coastal sources, sinks and strong organic complexation of dissolved cobalt within the US North Atlantic GEOTRACES transect GA03 Abigail E. Noble, Daniel C. Ohnemus, Nicholas J. Hawco, Phoebe J. Lam, and Mak A. Saito Biogeosciences, 14, 2715-2739, https://doi.org/10.5194/bg-14-2715-2017, 2017 This study examines sources and sinks of dissolved and labile cobalt in the North Atlantic Ocean. The North and South Atlantic are influenced differently by dust, coastal margin sources, biota, and suspended particles. Dissolved cobalt in both basins is driven by a coastal margin source, leading to large plumes emanating from the north and south African coasts. These plumes are comparable in size despite the high dust flux observed in the North Atlantic that is absent in the South Atlantic.

Description: Planktonic foraminifera-derived environmental DNA extracted from abyssal sediments preserves patterns of plankton macroecology Raphaël Morard, Franck Lejzerowicz, Kate F. Darling, Béatrice Lecroq-Bennet, Mikkel Winther Pedersen, Ludovic Orlando, Jan Pawlowski, Stefan Mulitza, Colomban de Vargas, and Michal Kucera Biogeosciences, 14, 2741-2754, https://doi.org/10.5194/bg-14-2741-2017, 2017 The exploitation of deep-sea sedimentary archive relies on the recovery of mineralized skeletons of pelagic organisms. Planktonic groups leaving preserved remains represent only a fraction of the total marine diversity. Environmental DNA left by non-fossil organisms is a promising source of information for paleo-reconstructions. Here we show how planktonic-derived environmental DNA preserves ecological structure of planktonic communities. We use planktonic foraminifera as a case study.

Description: Changing patterns of fire occurrence in proximity to forest edges, roads and rivers between NW Amazonian countries Dolors Armenteras, Joan Sebastian Barreto, Karyn Tabor, Roberto Molowny-Horas, and Javier Retana Biogeosciences, 14, 2755-2765, https://doi.org/10.5194/bg-14-2755-2017, 2017 Tropical forests are highly threatened by the expansion of the agricultural frontier, use of fire and subsequent deforestation. NW Amazonia is the wettest part of the basin and the role of fire is still largely unknown in this subregion. In this study, we compared fire regimes in five countries sharing this tropical biome (Venezuela, Colombia, Ecuador, Peru and Brazil). We studied fire activity in relation to proximity to roads and rivers and how fire occurs in relation to forest fragmentation.

Description: Carbon uptake and biogeochemical change in the Southern Ocean, south of Tasmania Paula C. Pardo, Bronte Tilbrook, Clothilde Langlais, Tom W. Trull, and Steve R. Rintoul Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-213,2017 Manuscript under review for BG (discussion: open, 0 comments) The carbon content of the water masses of the Southern Ocean, South of Tasmania has increased over the period 1995–2011, leading to a general decrease of pH. The long-term change in the carbon system is mainly affected by the ocean circulation and atmospheric features. The winds play an important role in the biogeochemical changes of upper to intermediate layers of the ocean while the ocean circulation conditions the long-term changes in deep waters.

Description: Increased temperature causes different carbon and nitrogen processing patterns in two common intertidal foraminifera ( Ammonia tepida and Haynesina germanica ) Julia Wukovits, Annekatrin Julie Enge, Wolfgang Wanek, Margarete Watzka, and Petra Heinz Biogeosciences, 14, 2815-2829, https://doi.org/10.5194/bg-14-2815-2017, 2017 This study reports the response of two intertidal foraminifera to increased temperatures on the level of carbon and nitrogen uptake. Interspecific variations in the ability to cope with shifting environmental variables within the two commonly associated species show that temperature and food source might be critical factors that control their abundances. This should support the interpretation of sediment samples and increase knowledge about nutrient fluxes through foraminiferal communities.

Description: An Orphan Problem Looking for Adoption: Responding to Ocean Acidification Utilising Existing International Institutions Ellycia R. Harrould-Kolieb Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-230,2017 Manuscript under review for BG (discussion: open, 0 comments) This research finds that there is a dearth of policy making pertaining to ocean acidification at the international level. Indeed, only three institutions are found to have initiated rue-making or implementation activities with the goal of either preventing worsening acidification or responding to its impacts. In light of this, this paper proposes that there are a variety of institutions that could be utilized to enhance the international response to ocean acidification.

Description: Seasonal variability of the inorganic carbon system in a large coastal plain estuary Andrew Joesoef, David L. Kirchman, Christopher K. Sommerfield, and Wei-Jun Cai Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-233,2017 Manuscript under review for BG (discussion: open, 0 comments) In this paper, we focus on key, poorly understood properties of carbonate geochemistry in one of the largest estuaries in North America. We explore how varying environmental factors impact total input and export inorganic carbon fluxes to the estuary and overall internal net ecosystem production within the system. In turn, recent and ongoing conclusions gained over this study provide broad implications to the inorganic carbon behavior and budget of present and future coastal ecosystems.

Description: The influence of the ocean circulation state on ocean carbon storage and CO 2 drawdown potential in an Earth system model Malin Ödalen, Jonas Nycander, Kevin I. C. Oliver, Laurent Brodeau, and Andy Ridgwell Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-166,2017 Manuscript under review for BG (discussion: open, 0 comments) During the four most recent glacial cycles, atmospheric CO 2 during glacial maxima has been lowered by about 90–100 ppm with respect to interglacials. There is widespread consensus that most of this carbon was partitioned in the ocean. It is however still debated which processes were dominant in achieving this increased carbon storage. In this paper, we use an Earth system model of intermediate complexity to constrain the range in ocean carbon storage for an ensemble of ocean circulation equilibrium states. We do a set of simulations where we run the model to pre-industrial equilibrium, but where we achieve different ocean circulation by changing forcing parameters such as wind stress, ocean diffusivity and atmospheric heat diffusivity. As a consequence, the ensemble members also have different ocean carbon reservoirs, global ocean average temperatures, biological pump efficiencies and conditions for air-sea CO 2 disequilibrium. We analyse changes in total ocean carbon storage and separate it into contributions by the solubility pump, the biological pump and the CO 2 disequilibrium component. We also relate these contributions to differences in strength of ocean overturning circulation. In cases with weaker circulation, we see that the ocean's capacity for carbon storage is larger. Depending on which ocean forcing parameter that is tuned, the origin of the change in carbon storage is different. When wind stress or ocean vertical diffusivity is changed, the response of the biological pump gives the most important effect on ocean carbon storage, whereas when atmospheric heat diffusivity or ocean horizontal diffusivity is changed, the solubility pump and the disequilibrium component are also important and sometimes dominant. Finally, we do a drawdown experiment, where we investigate the capacity for increased carbon storage by maximising the efficiency of the biological pump in our ensemble members. We conclude that different initial states for an ocean model result in different capacities for ocean carbon storage, due to differences in the ocean circulation state. This could explain why it is difficult to achieve comparable responses of the ocean carbon pumps in model intercomparison studies, where the initial states vary between models. The drawdown experiment highlights the importance of the strength of the biological pump in the control state for model studies of increased biological efficiency.

Description: Evidence for microbial mediated nitrate cycling within floodplain sediments during groundwater fluctuations Nicholas J. Bouskill, Mark E. Conrad, Markus Bill, Eoin L. Brodie, Yiwei Cheng, Chad Hobson, Matthew Forbes, Karen L. Casciotti, and Kenneth H. Williams Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-212,2017 Manuscript under review for BG (discussion: open, 0 comments) This work couples isotope geochemical techniques with mechanistic microbial modeling in an attempt to further unravel the major factors responsible for an observed reduction in nitrate concomitant with a rising water table within floodplain sediments. We focus on 3 depths below ground surface with different periods of saturation and varying degrees of microbial nitrate loss. Using a microbial model we identify the controlling factors on denitrification responsible for these differences.

Description: Biochar reduces yield-scaled emissions of reactive nitrogen gases from vegetable soils across China Changhua Fan, Hao Chen, Bo Li, and Zhengqin Xiong Biogeosciences, 14, 2851-2863, https://doi.org/10.5194/bg-14-2851-2017, 2017 Intensive vegetable fields suffered very low N use efficiency and very high N 2 O emissions as compared to other ecosystems. We have demonstrated that two contrasting biochars affected gaseous reactive nitrogen intensity (N 2 O, NO, NH 3 , yield) across four major vegetable soils in China. Biochar affects gaseous Nr or yield largely depending on soil types. Both wheat straw biochar ( B w ) and swine manure biochar ( B m ) decreased GNI with Bw mitigated gaseous Nr, whereas Bm improved yield.

Description: Climate engineering and the ocean: effects on biogeochemistry and primary production Siv K. Lauvset, Jerry Tjiputra, and Helene Muri Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-235,2017 Manuscript under review for BG (discussion: open, 0 comments) Solar radiation management (SRM) is suggested as a method to offset global warming and to buy time to reduce emissions. Here we use an Earth System Model to project the impact of SRM on future ocean biogeochemistry. This work underscores the complexity of climate impacts on ocean primary production, and highlights that changes are driven by an integrated effect of many environmental drivers, which all change in different ways.

Description: Ammonium and nitrate additions differentially affect soil microbial biomass of different communities and enzyme activities in slash pine plantation in subtropical China Chuang Zhang, Xin-Yu Zhang, Hong-Tao Zou, Liang Kou, Yang Yang, Xue-Fa Wen, Sheng-Gong Li, Hui-Min Wang, and Xiao-Min Sun Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-179,2017 Manuscript under review for BG (discussion: open, 0 comments) Ammonium additions had a stronger inhibition effects on soil microbial biomass of different community than nitrate addition. However, the inhibition effects of nitrate additions on P-hydrolase were stronger than ammonium additions, but not on C,N-hydrolase and oxidase. Ammonium additions decreased N-acquisition specific enzyme activities normalized by total microbial biomass, but increased P-acquisition specific enzyme activities. Different effects on soil pH may explained the different effects.

Description: Effects of warming on a Mediterranean phytoplankton community Silvia Pulina, Andreas Brutemark, Sanna Suikkanen, Bachisio M. Padedda, Lorena M. Grubisic, Cecilia T. Satta, Tiziana Caddeo, Pasqualina Farina, Nicola Sechi, and Antonella Lugliè Web Ecol., 16, 89-92, https://doi.org/10.5194/we-16-89-2016, 2016 In this work the effects of warming on phytoplankton communities was investigated. An indoor experiment was performed in which water from a Mediterranean lagoon was incubated at different temperatures. A shift towards smaller taxa resulted in a higher total biomass but lower chlorophyll a concentrations at the highest temperature. This study contributes to the knowledge on the responses of phytoplankton to warming, which is still scarce in Mediterranean marine and brackish environments.

Description: Overview of the translocation of rupestrian ferruginous fields of Capão Xavier mine to the Serra do Rola Moça State Park, Minas Gerais – Brazil Alessandra F. Fernandes, Ana C. Maia, Juan F. S. Monteiro, João N. Condé, and Mauro Martins Web Ecol., 16, 93-96, https://doi.org/10.5194/we-16-93-2016, 2016 The Serra do Rola Moça State Park is located in Brazil and is home to Canga vegetation. The objective of the study was to conserve biodiversity. The species present mainly belong to the Asteraceae, Rubiaceae, Myrtaceae, Velloziaceae, Bromeliaceae, and Orchidaceae families. Approximately 15 000 individuals of Canga species were translocated and planted. This study indicates the possibility of nursery breeding of some of the native species and their use in the recovery of areas in mining regions.

Description: Incorporating natural and human factors in habitat modelling and spatial prioritisation for the Lynx lynx martinoi K. Laze and A. Gordon Web Ecol., 16, 17-31, https://doi.org/10.5194/we-16-17-2016, 2016 We show areas for extending current protected areas and creating new ones for endangered sub-species of the Lynx lynx martinoi in the Albania–Macedonia–Kosovo and Montenegro–Albania–Kosovo cross-border areas. Our results highlight the importance international cooperation can have for lynx conservation. We used local knowledge on forests in the study area, our analytical skills, and our full interest in the lynx conservation. We did this study working remotely.

Description: Relations between environmental gradients and diversity indices of benthic invertebrates in lotic systems of northern Italy V. G. Aschonitis, G. Castaldelli, and E. A. Fano Web Ecol., 16, 13-15, https://doi.org/10.5194/we-16-13-2016, 2016 The relations between environmental gradients and traditional diversity indices (taxonomic richness, diversity and evenness) of benthic macroinvertebrate communities in the lotic systems of northern Italy were analyzed. Redundancy analysis (RDA) was used to describe the response of taxa to environmental gradients. Diversity indices were analyzed using generalized linear models (GLMs) with explanatory variables the first two major RDA axes.

Description: Peat decomposability in managed organic soils in relation to land-use, organic matter composition and temperature Cédric Bader, Moritz Müller, Rainer Schulin, and Jens Leifeld Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-187,2017 Manuscript under review for BG (discussion: open, 0 comments) Organic soils comprise a large yet fragile carbon (C) store in the global C cycle. Drainage, necessary for agriculture and forestry, triggers rapid decomposition of soil organic matter (SOM), typically increasing in the order forest 

Description: Coccolithophore fluxes in the open tropical North Atlantic: influence of the Amazon river and of Saharan dust deposition Catarina V. Guerreiro, Karl-Heinz Baumann, Geert-Jan A. Brummer, Gerhard Fischer, Laura F. Korte, Ute Merkel, Carolina Sá, Henko de Stigter, and Jan-Berend W. Stuut Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-216,2017 Manuscript under review for BG (discussion: open, 0 comments) Our study provides insights into the factors governing the spatiotemporal variability of coccolithophores in the equatorial North Atlantic, and illustrates how this supposedly oligotrophic and stable open-ocean region actually reveals significant ecological variability. We provide evidence for Saharan dust and the Amazon River acting as fertilizers for phytoplankton, and highlight the importance of coccolithophore productivity in the lower photic zone for the global oceanic carbonate budget.

Description: Modelling potential production and environmental effects of macroalgae farms in UK and Dutch coastal waters Johan van der Molen, Piet Ruardij, Karen Mooney, Philip Kerrison, Nessa E. O'Connor, Emma Gorman, Klaas Timmermans, Serena Wright, Maeve Kelly, Adam D. Hughes, and Elisa Capuzzo Biogeosciences Discuss., https//doi.org/10.5194/bg-2017-195,2017 Manuscript under review for BG (discussion: open, 0 comments) Macroalgae farming may provide biofuel. Modelled macroalgae production is given for four sites in UK and Dutch waters. No environmental effects were detected. Macroalgae growth depended on nutrient concentrations and light levels. Macroalgae carbohydrate content, important for biofuel use, was lower for high nutrient concentrations. The hypothetical large-scale farm off the UK north Norfolk coast gave high, stable yields of macroalgae from year to year with substantial carbohydrate content.