Articles | Volume 19, issue 8
25 Apr 2022
Research article | 25 Apr 2022
Modelling submerged biofouled microplastics and their vertical trajectories
Reint Fischer et al.
No articles found.
Stefanie Leonore Ypma, Quinten Bohte, Alexander Forryan, Alberto C. Naveira Garabato, Andy Donnelly, and Erik van Sebille
In this research we aim to improve cleanup efforts on the Galapagos Islands of marine plastic debris when resources are limited and the distribution of the plastic on shorelines is unknown. Using a network that describes the flow of macroplastic between the islands we have identified the most efficient cleanup locations, quantified the impact of targeting these locations and showed that shorelines where the plastic is unlikely to leave are likely efficient cleanup locations.
Pradeebane Vaittinada Ayar, Jerry Tjiputra, Laurent Bopp, Jim R. Christian, Tatiana Ilyina, John P. Krasting, Roland Séférian, Hiroyuki Tsujino, Michio Watanabe, and Andrew Yool
Earth Syst. Dynam. Discuss.,
Revised manuscript under review for ESDShort summary
The El Niño Southern Oscillation is the main driver for the natural variability of global atmospheric CO2. It modulates the CO2 fluxes in the tropical Pacific with anomalously CO2 influx during El Niño and outflux during La Niña. Climate projections under the business-as-usual scenario show a reversal of this behaviour is projected by half of Earth System Models. Changes in Revelle factor and subsurface distribution of dissolved Inorganic carbon are the two leading factors for this reversal.
Stephanie Woodward, Alistair Sellar, Yongming Tang, Marc Stringer, Andrew Yool, Eddy Robertson, and Andy Wiltshire
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
We describe the dust scheme in the UKESM1 earth system model and show generally good agreement with observations. Comparing with the closely related HadGEM3-GC3.1 model, we show that dust differences are not only due to inter-model differences, but also to the dust size distribution. Under climate change HadGEM3-GC3.1 dust hardly changes but UKESM1 dust decreases because that model includes the vegetation response, which in our models has a bigger impact on dust than does climate change itself.
Victor Onink, Erik van Sebille, and Charlotte Laufkötter
Geosci. Model Dev., 15, 1995–2012,Short summary
Turbulent mixing is a vital process in 3D modeling of particle transport in the ocean. However, since turbulence occurs on very short spatial scales and timescales, large-scale ocean models generally have highly simplified turbulence representations. We have developed parametrizations for the vertical turbulent transport of buoyant particles that can be easily applied in a large-scale particle tracking model. The predicted vertical concentration profiles match microplastic observations well.
Mikael L. A. Kaandorp, Stefanie L. Ypma, Marijke Boonstra, Henk A. Dijkstra, and Erik van Sebille
Ocean Sci., 18, 269–293,Short summary
A large amount of marine litter, such as plastics, is located on or around beaches. Both the total amount of this litter and its transport are poorly understood. We investigate this by training a machine learning model with data of cleanup efforts on Dutch beaches between 2014 and 2019, obtained by about 14 000 volunteers. We find that Dutch beaches contain up to 30 000 kg of litter, largely depending on tides, oceanic transport, and how exposed the beaches are.
Peter D. Nooteboom, Peter K. Bijl, Christian Kehl, Erik van Sebille, Martin Ziegler, Anna S. von der Heydt, and Henk A. Dijkstra
Earth Syst. Dynam., 13, 357–371,Short summary
Having descended through the water column, microplankton in ocean sediments represents the ocean surface environment and is used as an archive of past and present surface oceanographic conditions. However, this microplankton is advected by turbulent ocean currents during its sinking journey. We use simulations of sinking particles to define ocean bottom provinces and detect these provinces in datasets of sedimentary microplankton, which has implications for palaeoclimate reconstructions.
Josué Bock, Martine Michou, Pierre Nabat, Manabu Abe, Jane P. Mulcahy, Dirk J. L. Olivié, Jörg Schwinger, Parvadha Suntharalingam, Jerry Tjiputra, Marco van Hulten, Michio Watanabe, Andrew Yool, and Roland Séférian
Biogeosciences, 18, 3823–3860,Short summary
In this study we analyse surface ocean dimethylsulfide (DMS) concentration and flux to the atmosphere from four CMIP6 Earth system models over the historical and ssp585 simulations. Our analysis of contemporary (1980–2009) climatologies shows that models better reproduce observations in mid to high latitudes. The models disagree on the sign of the trend of the global DMS flux from 1980 onwards. The models agree on a positive trend of DMS over polar latitudes following sea-ice retreat dynamics.
C. Kehl, R. P. B. Fischer, and E. van Sebille
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., V-4-2021, 217–224,
Andrew Yool, Julien Palmiéri, Colin G. Jones, Lee de Mora, Till Kuhlbrodt, Ekatarina E. Popova, A. J. George Nurser, Joel Hirschi, Adam T. Blaker, Andrew C. Coward, Edward W. Blockley, and Alistair A. Sellar
Geosci. Model Dev., 14, 3437–3472,Short summary
The ocean plays a key role in modulating the Earth’s climate. Understanding this role is critical when using models to project future climate change. Consequently, it is necessary to evaluate their realism against the ocean's observed state. Here we validate UKESM1, a new Earth system model, focusing on the realism of its ocean physics and circulation, as well as its biological cycles and productivity. While we identify biases, generally the model performs well over a wide range of properties.
Rebeca de la Fuente, Gábor Drótos, Emilio Hernández-García, Cristóbal López, and Erik van Sebille
Ocean Sci., 17, 431–453,Short summary
Plastic pollution is a major environmental issue affecting the oceans. The number of floating and sedimented pieces has been quantified by several studies. But their abundance in the water column remains mostly unknown. To fill this gap we model the dynamics of a particular type of particle, rigid microplastics sinking rapidly in open sea in the Mediterranean. We find they represent a small but appreciable fraction of the total sea plastic and discuss characteristics of their sinking motion.
David Wichmann, Christian Kehl, Henk A. Dijkstra, and Erik van Sebille
Nonlin. Processes Geophys., 28, 43–59,Short summary
Fluid parcels transported in complicated flows often contain subsets of particles that stay close over finite time intervals. We propose a new method for detecting finite-time coherent sets based on the density-based clustering technique of ordering points to identify the clustering structure (OPTICS). Unlike previous methods, our method has an intrinsic notion of coherent sets at different spatial scales. OPTICS is readily implemented in the SciPy sklearn package, making it easy to use.
Jane P. Mulcahy, Colin Johnson, Colin G. Jones, Adam C. Povey, Catherine E. Scott, Alistair Sellar, Steven T. Turnock, Matthew T. Woodhouse, Nathan Luke Abraham, Martin B. Andrews, Nicolas Bellouin, Jo Browse, Ken S. Carslaw, Mohit Dalvi, Gerd A. Folberth, Matthew Glover, Daniel P. Grosvenor, Catherine Hardacre, Richard Hill, Ben Johnson, Andy Jones, Zak Kipling, Graham Mann, James Mollard, Fiona M. O'Connor, Julien Palmiéri, Carly Reddington, Steven T. Rumbold, Mark Richardson, Nick A. J. Schutgens, Philip Stier, Marc Stringer, Yongming Tang, Jeremy Walton, Stephanie Woodward, and Andrew Yool
Geosci. Model Dev., 13, 6383–6423,Short summary
Aerosols are an important component of the Earth system. Here, we comprehensively document and evaluate the aerosol schemes as implemented in the physical and Earth system models, HadGEM3-GC3.1 and UKESM1. This study provides a useful characterisation of the aerosol climatology in both models, facilitating the understanding of the numerous aerosol–climate interaction studies that will be conducted for CMIP6 and beyond.
Chris S. M. Turney, Richard T. Jones, Nicholas P. McKay, Erik van Sebille, Zoë A. Thomas, Claus-Dieter Hillenbrand, and Christopher J. Fogwill
Earth Syst. Sci. Data, 12, 3341–3356,Short summary
The Last Interglacial (129–116 ka) experienced global temperatures and sea levels higher than today. The direct contribution of warmer conditions to global sea level (thermosteric) are uncertain. We report a global network of sea surface temperatures. We find mean global annual temperature anomalies of 0.2 ± 0.1˚C and an early maximum peak of 0.9 ± 0.1˚C. Our reconstruction suggests warmer waters contributed on average 0.08 ± 0.1 m and a peak contribution of 0.39 ± 0.1 m to global sea level.
Linda K. Dämmer, Lennart de Nooijer, Erik van Sebille, Jan G. Haak, and Gert-Jan Reichart
Clim. Past, 16, 2401–2414,Short summary
The compositions of foraminifera shells often vary with environmental parameters such as temperature or salinity; thus, they can be used as proxies for these environmental variables. Often a single proxy is influenced by more than one parameter. Here, we show that while salinity impacts shell Na / Ca, temperature has no effect. We also show that the combination of different proxies (Mg / Ca and δ18O) to reconstruct salinity does not seem to work as previously thought.
David Wichmann, Christian Kehl, Henk A. Dijkstra, and Erik van Sebille
Nonlin. Processes Geophys., 27, 501–518,Short summary
The surface transport of heat, nutrients and plastic in the North Atlantic Ocean is organized into large-scale flow structures. We propose a new and simple method to detect such features in ocean drifter data sets by identifying groups of trajectories with similar dynamical behaviour using network theory. We successfully detect well-known regions such as the Subpolar and Subtropical gyres, the Western Boundary Current region and the Caribbean Sea.
Mirjam van der Mheen, Erik van Sebille, and Charitha Pattiaratchi
Ocean Sci., 16, 1317–1336,Short summary
A large percentage of global ocean plastic enters the Indian Ocean through rivers, but the fate of these plastics is generally unknown. In this paper, we use computer simulations to show that floating plastics
beachand end up on coastlines throughout the Indian Ocean. Coastlines where a lot of plastic enters the ocean are heavily affected by beaching plastic, but plastics can also beach far from the source on remote islands and countries that contribute little plastic pollution of their own.
Lee de Mora, Alistair A. Sellar, Andrew Yool, Julien Palmieri, Robin S. Smith, Till Kuhlbrodt, Robert J. Parker, Jeremy Walton, Jeremy C. Blackford, and Colin G. Jones
Geosci. Commun., 3, 263–278,Short summary
We use time series data from the first United Kingdom Earth System Model (UKESM1) to create six procedurally generated musical pieces for piano. Each of the six pieces help to explain either a scientific principle or a practical aspect of Earth system modelling. We describe the methods that were used to create these pieces, discuss the limitations of this pilot study and list several approaches to extend and expand upon this work.
Lester Kwiatkowski, Olivier Torres, Laurent Bopp, Olivier Aumont, Matthew Chamberlain, James R. Christian, John P. Dunne, Marion Gehlen, Tatiana Ilyina, Jasmin G. John, Andrew Lenton, Hongmei Li, Nicole S. Lovenduski, James C. Orr, Julien Palmieri, Yeray Santana-Falcón, Jörg Schwinger, Roland Séférian, Charles A. Stock, Alessandro Tagliabue, Yohei Takano, Jerry Tjiputra, Katsuya Toyama, Hiroyuki Tsujino, Michio Watanabe, Akitomo Yamamoto, Andrew Yool, and Tilo Ziehn
Biogeosciences, 17, 3439–3470,Short summary
We assess 21st century projections of marine biogeochemistry in the CMIP6 Earth system models. These models represent the most up-to-date understanding of climate change. The models generally project greater surface ocean warming, acidification, subsurface deoxygenation, and euphotic nitrate reductions but lesser primary production declines than the previous generation of models. This has major implications for the impact of anthropogenic climate change on marine ecosystems.
Erik van Sebille, Philippe Delandmeter, John Schofield, Britta Denise Hardesty, Jen Jones, and Andy Donnelly
Ocean Sci., 15, 1341–1349,Short summary
The Galápagos Archipelago and Galápagos Marine Reserve are among the world's most iconic wildlife refuges. Yet, plastic litter is now found even in this remote archipelago. It is unclear where this plastic originates from. In this study, we show that remote coastal sources of plastic pollution are fairly localized and limited to South American and Central American coastlines. Identifying how plastic ends up in the Galápagos aids integrated management opportunities to reduce plastic pollution.
Philippe Delandmeter and Erik van Sebille
Geosci. Model Dev., 12, 3571–3584,Short summary
Parcels is a framework to compute how ocean currents transport
stuffsuch as plankton and plastic around. In the latest version 2.0 of Parcels, we focus on more accurate interpolation schemes and implement methods to seamlessly combine data from different sources (such as winds and currents, possibly in different regions). We show that this framework is very efficient for tracking how microplastic is transported through the North Sea into the Arctic.
Matthew P. Couldrey, Kevin I. C. Oliver, Andrew Yool, Paul R. Halloran, and Eric P. Achterberg
Revised manuscript not acceptedShort summary
Determining how much carbon dioxide (CO2) the oceans absorb is key to predicting human-caused climate change. A computer model of the ocean shows how the North Atlantic will change up to the end of the century. Year-to-year variations are mostly caused by changes in ocean temperature and seawater chemistry, altering CO2 solubility. By 2100, human emissions cause the biggest changes. The near term changes are physically driven, which may be more predictable than biological changes.
Ben A. Ward, Jamie D. Wilson, Ros M. Death, Fanny M. Monteiro, Andrew Yool, and Andy Ridgwell
Geosci. Model Dev., 11, 4241–4267,Short summary
A novel configuration of an Earth system model includes a diverse plankton community. The model – EcoGEnIE – is sufficiently complex to reproduce a realistic, size-structured plankton community, while at the same time retaining the efficiency to run to a global steady state (~ 10k years). The increased capabilities of EcoGEnIE will allow future exploration of ecological communities on much longer timescales than have so far been examined in global ocean models and particularly for past climate.
Lee de Mora, Andrew Yool, Julien Palmieri, Alistair Sellar, Till Kuhlbrodt, Ekaterina Popova, Colin Jones, and J. Icarus Allen
Geosci. Model Dev., 11, 4215–4240,Short summary
Climate change is expected to have a significant impact on the Earth's weather, ice caps, land surface, and ocean. Computer models of the Earth system are the only tools available to make predictions about how the climate may change in the future. However, in order to trust the model predictions, we must first demonstrate that the models have a realistic description of the past. The BGC-val toolkit was built to rapidly and simply evaluate the behaviour of models of the Earth's oceans.
Fabrice Ardhuin, Yevgueny Aksenov, Alvise Benetazzo, Laurent Bertino, Peter Brandt, Eric Caubet, Bertrand Chapron, Fabrice Collard, Sophie Cravatte, Jean-Marc Delouis, Frederic Dias, Gérald Dibarboure, Lucile Gaultier, Johnny Johannessen, Anton Korosov, Georgy Manucharyan, Dimitris Menemenlis, Melisa Menendez, Goulven Monnier, Alexis Mouche, Frédéric Nouguier, George Nurser, Pierre Rampal, Ad Reniers, Ernesto Rodriguez, Justin Stopa, Céline Tison, Clément Ubelmann, Erik van Sebille, and Jiping Xie
Ocean Sci., 14, 337–354,Short summary
The Sea surface KInematics Multiscale (SKIM) monitoring mission is a proposal for a future satellite that is designed to measure ocean currents and waves. Using a Doppler radar, the accurate measurement of currents requires the removal of the mean velocity due to ocean wave motions. This paper describes the main processing steps needed to produce currents and wave data from the radar measurements. With this technique, SKIM can provide unprecedented coverage and resolution, over the global ocean.
Michael Lange and Erik van Sebille
Geosci. Model Dev., 10, 4175–4186,Short summary
Here, we present version 0.9 of Parcels (Probably A Really Computationally Efficient Lagrangian Simulator). Parcels is an experimental prototype code aimed at exploring novel approaches for Lagrangian tracking of virtual ocean particles in the petascale age. The modularity, flexibility and scalability will allow the code to be used to track water, nutrients, microbes, plankton, plastic and even fish.
Chris S. M. Turney, Christopher J. Fogwill, Jonathan G. Palmer, Erik van Sebille, Zoë Thomas, Matt McGlone, Sarah Richardson, Janet M. Wilmshurst, Pavla Fenwick, Violette Zunz, Hugues Goosse, Kerry-Jayne Wilson, Lionel Carter, Mathew Lipson, Richard T. Jones, Melanie Harsch, Graeme Clark, Ezequiel Marzinelli, Tracey Rogers, Eleanor Rainsley, Laura Ciasto, Stephanie Waterman, Elizabeth R. Thomas, and Martin Visbeck
Clim. Past, 13, 231–248,Short summary
The Southern Ocean plays a fundamental role in global climate but suffers from a dearth of observational data. As the Australasian Antarctic Expedition 2013–2014 we have developed the first annually resolved temperature record using trees from subantarctic southwest Pacific (52–54˚S) to extend the climate record back to 1870. With modelling we show today's high climate variability became established in the ~1940s and likely driven by a Rossby wave response originating from the tropical Pacific.
Christopher J. Fogwill, Erik van Sebille, Eva A. Cougnon, Chris S. M. Turney, Steve R. Rintoul, Benjamin K. Galton-Fenzi, Graeme F. Clark, E. M. Marzinelli, Eleanor B. Rainsley, and Lionel Carter
The Cryosphere, 10, 2603–2609,Short summary
Here we report new data from in situ oceanographic surveys and high-resolution ocean modelling experiments in the Commonwealth Bay region of East Antarctica, where in 2010 there was a major reconfiguration of the regional icescape due to the collision of the 97 km long iceberg B09B with the Mertz Glacier tongue. Here we compare post-calving observations with high-resolution ocean modelling which suggest that this reconfiguration has led to the development of a new polynya off Commonwealth Bay.
Claudie Beaulieu, Harriet Cole, Stephanie Henson, Andrew Yool, Thomas R. Anderson, Lee de Mora, Erik T. Buitenhuis, Momme Butenschön, Ian J. Totterdell, and J. Icarus Allen
Biogeosciences, 13, 4533–4553,Short summary
Regime shifts have been suggested in the late 1970s and late 1980s in the Gulf of Alaska with important consequences for fisheries. Here we investigate the ability of a suite of ocean biogeochemical models of varying complexity to simulate these regime shifts. Our results demonstrate that ocean models can successfully simulate regime shifts in the Gulf of Alaska region, thereby improving our understanding of how changes in physical conditions are propagated from lower to upper trophic levels.
Paulina Cetina-Heredia, Erik van Sebille, Richard Matear, and Moninya Roughan
Revised manuscript not acceptedShort summary
Characterizing phytoplankton growth influences fisheries and climate. We use a lagrangian approach to identify phytoplankton blooms in the Great Australian Bight (GAB), and associate them with nitrate sources. We find that 88 % of the nitrate utilized in blooms is originated between the GAB and the SubAntarctic Front. Large nitrate concentrations are supplied at depth but do not reach the euphotic zone often. As a result, 55 % of blooms utilize nitrate supplied in the top 100 m.
T. R. Anderson, W. C. Gentleman, and A. Yool
Geosci. Model Dev., 8, 2231–2262,Short summary
Ecosystem models provide a powerful tool for simulating ocean biology. Care must be exercised when selecting appropriate equations and parameter values to represent chosen marine ecosystems. Here, we present an efficient plankton model testbed, using simplified physics and coded in the freely available language R. Multiple runs can be undertaken for different ocean sites, permitting thorough evaluation of ecosystem model performance. The testbed also serves as an excellent resource for teaching.
J. C. P. Hemmings, P. G. Challenor, and A. Yool
Geosci. Model Dev., 8, 697–731,Short summary
Effective calibration of global models is inhibited by the computational demands of 3-D simulations. As a solution for the NEMO-MEDUSA model, we present an efficient emulator of surface chlorophyll as a function of MEDUSA’s biogeochemical parameters. The emulator comprises an array of site-based 1-D simulators and a quantification of uncertainty in their predictions. It is able to produce robust probabilistic estimates of 3-D model output rapidly for comparison with satellite chlorophyll.
L. Kwiatkowski, A. Yool, J. I. Allen, T. R. Anderson, R. Barciela, E. T. Buitenhuis, M. Butenschön, C. Enright, P. R. Halloran, C. Le Quéré, L. de Mora, M.-F. Racault, B. Sinha, I. J. Totterdell, and P. M. Cox
Biogeosciences, 11, 7291–7304,
B. A. Kelly-Gerreyn, A. P. Martin, B. J. Bett, T. R. Anderson, J. I. Kaariainen, C. E. Main, C. J. Marcinko, and A. Yool
Biogeosciences, 11, 6401–6416,
E. E. Popova, A. Yool, Y. Aksenov, A. C. Coward, and T. R. Anderson
Biogeosciences, 11, 293–308,
A. Yool, E. E. Popova, and T. R. Anderson
Geosci. Model Dev., 6, 1767–1811,
A. Yool, E. E. Popova, A. C. Coward, D. Bernie, and T. R. Anderson
Biogeosciences, 10, 5831–5854,
S. Henson, H. Cole, C. Beaulieu, and A. Yool
Biogeosciences, 10, 4357–4369,
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Michelle Viswanathan, Tobias K. D. Weber, Sebastian Gayler, Juliane Mai, and Thilo Streck
Biogeosciences, 19, 2187–2209,Short summary
We analysed the evolution of model parameter uncertainty and prediction error as we updated parameters of a maize phenology model based on yearly observations, by sequentially applying Bayesian calibration. Although parameter uncertainty was reduced, prediction quality deteriorated when calibration and prediction data were from different maize ripening groups or temperature conditions. The study highlights that Bayesian methods should account for model limitations and inherent data structures.
Jessica Kolbusz, Tim Langlois, Charitha Pattiaratchi, and Simon de Lestang
Biogeosciences, 19, 517–539,Short summary
Western rock lobster larvae spend up to 11 months in offshore waters before ocean currents and their ability to swim transport them back to the coast. In 2008, there was a reduction in the number of puerulus (larvae) settling into the fishery. We use an oceanographic model to see how the environment may have contributed to the reduction. Our results show that a combination of effects from local currents and a widespread quiet period in the ocean off WA likely led to less puerulus settlement.
Rémy Asselot, Frank Lunkeit, Philip B. Holden, and Inga Hense
Biogeosciences, 19, 223–239,Short summary
Previous studies show that phytoplankton light absorption can warm the atmosphere, but how this warming occurs is still unknown. We compare the importance of air–sea heat versus CO2 flux in the phytoplankton-induced atmospheric warming and determine the main driver. To shed light on this research question, we conduct simulations with a climate model of intermediate complexity. We show that phytoplankton mainly warms the atmosphere by increasing the air–sea CO2 flux.
Roxane Tzortzis, Andrea M. Doglioli, Stéphanie Barrillon, Anne A. Petrenko, Francesco d'Ovidio, Lloyd Izard, Melilotus Thyssen, Ananda Pascual, Bàrbara Barceló-Llull, Frédéric Cyr, Marc Tedetti, Nagib Bhairy, Pierre Garreau, Franck Dumas, and Gérald Gregori
Biogeosciences, 18, 6455–6477,Short summary
This work analyzes an original high-resolution data set collected in the Mediterranean Sea. The major result is the impact of a fine-scale frontal structure on the distribution of phytoplankton groups, in an area of moderate energy with oligotrophic conditions. Our results provide an in situ confirmation of the findings obtained by previous modeling studies and remote sensing about the structuring effect of the fine-scale ocean dynamics on the structure of the phytoplankton community.
Johannes Vogel, Eva Paton, and Valentin Aich
Biogeosciences, 18, 5903–5927,Short summary
This study investigates extreme ecosystem impacts evoked by temperature and soil moisture in the Mediterranean Basin for the time span 1999–2019 with a specific focus on seasonal variations. The analysis showed that ecosystem vulnerability is caused by several varying combinations of both drivers during the yearly cycle. The approach presented here helps to provide insights on the specific phenological stage of the year in which ecosystem vulnerability to a certain climatic condition occurs.
Mara Freilich, Alexandre Mignot, Glenn Flierl, and Raffaele Ferrari
Biogeosciences, 18, 5595–5607,Short summary
Observations reveal that in some regions phytoplankton biomass increases during the wintertime when growth conditions are sub-optimal, which has been attributed to a release from grazing during mixed layer deepening. Measurements of grazer populations to support this theory are lacking. We demonstrate that a release from grazing when the winter mixed layer is deepening holds only for certain grazing models, extending the use of phytoplankton observations to make inferences about grazer dynamics.
Shuangling Chen, Mark L. Wells, Rui Xin Huang, Huijie Xue, Jingyuan Xi, and Fei Chai
Biogeosciences, 18, 5539–5554,Short summary
Subduction transports surface waters to the oceanic interior, which can supply significant amounts of carbon and oxygen to the twilight zone. Using a novel BGC-Argo dataset covering the western North Pacific, we successfully identified the imprints of episodic shallow subduction patches. These subduction patches were observed mainly in spring and summer (70.6 %), and roughly half of them extended below ~ 450 m, injecting carbon- and oxygen-enriched waters into the ocean interior.
Pierre Damien, Julio Sheinbaum, Orens Pasqueron de Fommervault, Julien Jouanno, Lorena Linacre, and Olaf Duteil
Biogeosciences, 18, 4281–4303,Short summary
The Gulf of Mexico deep waters are relatively poor in phytoplankton biomass due to low levels of nutrients in the upper layers. Using modeling techniques, we find that the long-living anticyclonic Loop Current eddies that are shed episodically from the Yucatan Channel strongly shape the distribution of phytoplankton and, more importantly, stimulate their growth. This results from the contribution of multiple mechanisms of physical–biogeochemical interactions discussed in this study.
Sergey V. Stanichny, Elena A. Kubryakova, and Arseny A. Kubryakov
Biogeosciences, 18, 3173–3188,Short summary
In this paper, we show that the short-term impact of tropical cyclones can trigger the intense, long-term bloom of coccolithophores, which are major marine calcifiers playing an important role in the balance and fluxes of inorganic carbon in the ocean. In our paper, we describe the evolution of and physical reasons for such an unusual bloom observed in autumn 2005 in the Black Sea on the basis of satellite data.
Fengshan Liu, Ying Chen, Nini Bai, Dengpan Xiao, Huizi Bai, Fulu Tao, and Quansheng Ge
Biogeosciences, 18, 2275–2287,Short summary
The sowing date is key to the surface biophysical processes in the winter dormancy period. The climate effect of the sowing date shift is therefore very interesting and may contribute to the mitigation of climate change. An earlier sowing date always had a higher LAI but a higher temperature in the dormancy period and a lower temperature in the growth period. The main reason was the relative contributions of the surface albedo and energy partitioning processes.
Peter Aartsma, Johan Asplund, Arvid Odland, Stefanie Reinhardt, and Hans Renssen
Biogeosciences, 18, 1577–1599,Short summary
In the literature, it is generally assumed that alpine lichen heaths keep their direct environment cool due to their relatively high albedo. However, we reveal that the soil temperature and soil heat flux are higher below lichens than below shrubs during the growing season, despite a lower net radiation for lichens. We also show that the differences in microclimatic conditions between these two vegetation types are more pronounced during warm and sunny days than during cold and cloudy days.
Oleg Sizov, Ekaterina Ezhova, Petr Tsymbarovich, Andrey Soromotin, Nikolay Prihod'ko, Tuukka Petäjä, Sergej Zilitinkevich, Markku Kulmala, Jaana Bäck, and Kajar Köster
Biogeosciences, 18, 207–228,Short summary
In changing climate, tundra is expected to turn into shrubs and trees, diminishing reindeer pasture and increasing risks of tick-borne diseases. However, this transition may require a disturbance. Fires in Siberia are increasingly widespread. We studied wildfire dynamics and tundra–forest transition over 60 years in northwest Siberia near the Arctic Circle. Based on satellite data analysis, we found that transition occurs in 40 %–85 % of burned tundra compared to 5 %–15 % in non-disturbed areas.
Kaveh Purkiani, André Paul, Annemiek Vink, Maren Walter, Michael Schulz, and Matthias Haeckel
Biogeosciences, 17, 6527–6544,Short summary
There has been a steady increase in interest in mining of deep-sea minerals in the eastern Pacific Ocean recently. The ocean state in this region is known to be highly influenced by rotating bodies of water (eddies), some of which can travel long distances in the ocean and impact the deeper layers of the ocean. Better insight into the variability of eddy activity in this region is of great help to mitigate the impact of the benthic ecosystem from future potential deep-sea mining activity.
Jing Yan, Nathaniel A. Bogie, and Teamrat A. Ghezzehei
Biogeosciences, 17, 6377–6392,Short summary
An uneven supply of water and nutrients in soils often drives how plants behave. We observed that plants extract all their required nutrients from dry soil patches in sufficient quantity, provided adequate water is available elsewhere in the root zone. Roots in nutrient-rich dry patches facilitate the nutrient acquisition by extensive growth, water release, and modifying water retention in their immediate environment. The findings are valuable in managing nutrient losses in agricultural systems.
Onur Kerimoglu, Yoana G. Voynova, Fatemeh Chegini, Holger Brix, Ulrich Callies, Richard Hofmeister, Knut Klingbeil, Corinna Schrum, and Justus E. E. van Beusekom
Biogeosciences, 17, 5097–5127,Short summary
In this study, using extensive field observations and a numerical model, we analyzed the physical and biogeochemical structure of a coastal system following an extreme flood event. Our results suggest that a number of anomalous observations were driven by a co-occurrence of peculiar meteorological conditions and increased riverine discharges. Our results call for attention to the combined effects of hydrological and meteorological extremes that are anticipated to increase in frequency.
Amandine Erktan, Matthias C. Rillig, Andrea Carminati, Alexandre Jousset, and Stefan Scheu
Biogeosciences, 17, 4961–4980,Short summary
Soil aggregation is crucial for soil functioning. While the role of bacteria and fungi in soil aggregation is well established, how predators feeding on microbes modify soil aggregation has hardly been investigated. We showed for the first time that protists modify soil aggregation, presumably through changes in the production of bacterial mucilage, and that collembolans reduce soil aggregation, presumably by reducing the abundance of saprotrophic fungi.
Wei Hu, Kotaro Murata, Chunlan Fan, Shu Huang, Hiromi Matsusaki, Pingqing Fu, and Daizhou Zhang
Biogeosciences, 17, 4477–4487,Short summary
This paper reports the first estimate of the status of bacteria in long-distance-transported Asian dust, demonstrating that airborne dust, which can carry viable and nonviable bacteria on particle surfaces, is an efficient medium for constantly spreading bacteria at regional and even global scales. Such data are essential to better model and understand the roles and activities of bioaerosols in environmental evolution and climate change and the potential risks of bioaerosols to human health.
Inge Grünberg, Evan J. Wilcox, Simon Zwieback, Philip Marsh, and Julia Boike
Biogeosciences, 17, 4261–4279,Short summary
Based on topsoil temperature data for different vegetation types at a low Arctic tundra site, we found large small-scale variability. Winter temperatures were strongly influenced by vegetation through its effects on snow. Summer temperatures were similar below most vegetation types and not consistently related to late summer permafrost thaw depth. Given that vegetation type defines the relationship between winter and summer soil temperature and thaw depth, it controls permafrost vulnerability.
Long Jiang, Theo Gerkema, Jacco C. Kromkamp, Daphne van der Wal, Pedro Manuel Carrasco De La Cruz, and Karline Soetaert
Biogeosciences, 17, 4135–4152,Short summary
A seaward increasing chlorophyll-a gradient is observed during the spring bloom in a Dutch tidal bay. Biophysical model runs indicate the roles of bivalve grazing and tidal import in shaping the gradient. Five common spatial phytoplankton patterns are summarized in global estuarine–coastal ecosystems: seaward increasing, seaward decreasing, concave with a chlorophyll maximum, weak spatial gradients, and irregular patterns.
Emil De Borger, Justin Tiano, Ulrike Braeckman, Tom Ysebaert, and Karline Soetaert
Biogeosciences, 17, 1701–1715,Short summary
By applying a novel technique to quantify organism-induced sediment–water column fluid exchange (bioirrigation), we show that organisms in subtidal (permanently submerged) areas have similar bioirrigation rates as those that inhabit intertidal areas (not permanently submerged), but organisms in the latter irrigate deeper burrows in this study. Our results expand on traditional methods to quantify bioirrigation rates and broaden the pool of field measurements of bioirrigation rates.
Sheila N. Estrada-Allis, Julio Sheinbaum Pardo, Joao M. Azevedo Correia de Souza, Cecilia Elizabeth Enríquez Ortiz, Ismael Mariño Tapia, and Jorge A. Herrera-Silveira
Biogeosciences, 17, 1087–1111,Short summary
Continental shelves are the most productive areas in the ocean and can have an important impact on the nutrient cycle as well as the climate system. The one in Yucatán is the largest shelf in the Gulf of Mexico. However, its nutrient budget remains unidentifiable. Here we propose not only a general nutrient budget for the Yucatán Shelf but also the physical processes responsible for its pathway modulation through a physical–biogeochemical coupled model of the whole Gulf of Mexico.
Ashley Dubnick, Martin Sharp, Brad Danielson, Alireza Saidi-Mehrabad, and Joel Barker
Biogeosciences, 17, 963–977,Short summary
We found that glaciers with basal temperatures near the melting point mobilize more solutes, nutrients, and microbes from the underlying substrate and are more likely to promote in situ biogeochemical activity than glaciers with basal temperatures well below the melting point. The temperature at the base of glaciers is therefore an important control on the biogeochemistry of ice near glacier beds, and, ultimately, the potential solutes, nutrients, and microbes exported from glaciated watersheds.
Audrey Delpech, Anna Conchon, Olivier Titaud, and Patrick Lehodey
Biogeosciences, 17, 833–850,Short summary
Micronekton is an important, yet poorly known, component of the trophic chain, which partly contributes to the storage of CO2 in the deep ocean thanks to biomass vertical migrations. In this study, we characterize the ideal sampling regions to estimate the amount of biomass that undergoes theses migrations. We find that observations made in warm, nondynamic and productive waters reduce the error of the estimation by 20 %. This result should likely serve for future in situ network deployment.
Filippos Tagklis, Takamitsu Ito, and Annalisa Bracco
Biogeosciences, 17, 231–244,Short summary
Deoxygenation of the oceans is potentially one of the most severe ecosystem stressors resulting from global warming given the high sensitivity of dissolved oxygen to ocean temperatures. Climate models suggest that despite the thermodynamic tendency of the oceans to lose oxygen, certain regions experience significant changes in the biologically driven O2 consumption, resulting in a resistance against deoxygenation. Overturning circulation changes are responsible for such a behavior.
Mohammad Abdul Halim, Han Y. H. Chen, and Sean C. Thomas
Biogeosciences, 16, 4357–4375,Short summary
Using field data collected over 4 years across a range of stand ages, we investigated how seasonal surface albedo in boreal forest varies with stand age, stand structure, and composition. Our results indicate that successional change in species composition is a key driver of age–related patterns in albedo, with hardwood species associated with higher albedo. The patterns described have important implications for both climate modeling and
climate–smartboreal forest management.
Paul A. Moore, Maxwell C. Lukenbach, Dan K. Thompson, Nick Kettridge, Gustaf Granath, and James M. Waddington
Biogeosciences, 16, 3491–3506,Short summary
Using very-high-resolution digital elevation models (DEMs), we assessed the basic structure and microtopographic variability of hummock–hollow plots at boreal and hemi-boreal sites primarily in North America. Using a simple model of peatland biogeochemical function, our results suggest that both surface heating and moss productivity may not be adequately resolved in models which only consider idealized hummock–hollow units.
Renee K. Gruber, Ryan J. Lowe, and James L. Falter
Biogeosciences, 16, 1921–1935,Short summary
Researchers from the University of Western Australia's Oceans Institute are studying large tides (up to 12 m range) that occur in the Kimberley region of Australia. These tides flush coral reefs with water rich in nutrients, which supports the growth of reef organisms. In this paper, we show how tidal cycles and seasons control nutrient availability on reefs. This study is among the first published accounts of reefs and water quality data in the remote and pristine Kimberley region.
Sergey A. Marakushev and Ol'ga V. Belonogova
Biogeosciences, 16, 1817–1828,Short summary
Among the existing theories of the autotrophic origin of life, CO2 is usually considered to be the carbon source for nascent autotrophic metabolism. However, ancestral carbon used in metabolism may have been derived from CH4 if the outflow of magma fluid to the surface of the Earth consisted mainly of methane. The hydrothermal system model is considered in the form of a phase diagram, which demonstrates the area of redox and P and T conditions favorable to development of primary methanotroph.
Venugopal Thushara, Puthenveettil Narayana Menon Vinayachandran, Adrian J. Matthews, Benjamin G. M. Webber, and Bastien Y. Queste
Biogeosciences, 16, 1447–1468,Short summary
Chlorophyll distribution in the ocean remains to be explored in detail, despite its climatic significance. Here, we document the vertical structure of chlorophyll in the Bay of Bengal using observations and a model. The shape of chlorophyll profiles, characterized by prominent deep chlorophyll maxima, varies in dynamically different regions, controlled by the monsoonal forcings. The present study provides new insights into the vertical distribution of chlorophyll, rarely observed by satellites.
Soeren Thomsen, Johannes Karstensen, Rainer Kiko, Gerd Krahmann, Marcus Dengler, and Anja Engel
Biogeosciences, 16, 979–998,Short summary
Physical and biogeochemical observations from an autonomous underwater vehicle in combination with ship-based measurements are used to investigate remote and local drivers of the oxygen and nutrient variability off Mauritania. Beside the transport of oxygen and nutrients characteristics from remote areas towards Mauritania also local remineralization of organic material close to the seabed seems to be important for the distribution of oxygen and nutrients.
Pascale Bouruet-Aubertot, Yannis Cuypers, Andrea Doglioli, Mathieu Caffin, Christophe Yohia, Alain de Verneil, Anne Petrenko, Dominique Lefèvre, Hervé Le Goff, Gilles Rougier, Marc Picheral, and Thierry Moutin
Biogeosciences, 15, 7485–7504,Short summary
The OUTPACE cruise took place between New Caledonia and French Polynesia. The main purpose was to understand how micro-organisms can survive in a very poor environment. One main source of nutrients is at depth, below the euphotic layer where micro-organisms live. The purpose of the turbulence measurements was to determine to which extent turbulence may
upliftnutrients into the euphotic layer. The origin of the turbulence that was found contrasted along the transect was also determined.
Daniel D. Richter, Sharon A. Billings, Peter M. Groffman, Eugene F. Kelly, Kathleen A. Lohse, William H. McDowell, Timothy S. White, Suzanne Anderson, Dennis D. Baldocchi, Steve Banwart, Susan Brantley, Jean J. Braun, Zachary S. Brecheisen, Charles W. Cook, Hilairy E. Hartnett, Sarah E. Hobbie, Jerome Gaillardet, Esteban Jobbagy, Hermann F. Jungkunst, Clare E. Kazanski, Jagdish Krishnaswamy, Daniel Markewitz, Katherine O'Neill, Clifford S. Riebe, Paul Schroeder, Christina Siebe, Whendee L. Silver, Aaron Thompson, Anne Verhoef, and Ganlin Zhang
Biogeosciences, 15, 4815–4832,Short summary
As knowledge in biology and geology explodes, science becomes increasingly specialized. Given the overlap of the environmental sciences, however, the explosion in knowledge inevitably creates opportunities for interconnecting the biogeosciences. Here, 30 scientists emphasize the opportunities for biogeoscience collaborations across the world’s remarkable long-term environmental research networks that can advance science and engage larger scientific and public audiences.
Ivy Frenger, Matthias Münnich, and Nicolas Gruber
Biogeosciences, 15, 4781–4798,Short summary
Although mesoscale ocean eddies are ubiquitous in the Southern Ocean (SO), their regional and seasonal association with phytoplankton has not been quantified. We identify over 100 000 eddies and determine the associated phytoplankton biomass anomalies using satellite-based chlorophyll (Chl) as a proxy. The emerging Chl anomalies can be explained largely by lateral advection of Chl by eddies. This impact of eddies on phytoplankton may implicate downstream effects on SO biogeochemical properties.
Yi Sun, Xiong Z. He, Fujiang Hou, Zhaofeng Wang, and Shenghua Chang
Biogeosciences, 15, 4233–4243,Short summary
To investigate how grazing alters litter composition, quality and decomposition, we collected litter from grazing (GP) and grazing exclusion paddocks (GEP) and incubated them in situ and across sites. Grazing increased litter N and grazing exclusion increased litter mass of palatable species and promoted SOC. Litter decomposed faster in GP and N was opposite. Site environment had more impact on litter decomposition. Results may be helpful in developing strategies to restore degraded grasslands.
Louise Rousselet, Alain de Verneil, Andrea M. Doglioli, Anne A. Petrenko, Solange Duhamel, Christophe Maes, and Bruno Blanke
Biogeosciences, 15, 2411–2431,Short summary
The patterns of the large- and fine-scale surface circulation on biogeochemical and biological distributions are examined in the western tropical South Pacific (WTSP) in the context of the OUTPACE oceanographic cruise. The combined use of in situ and satellite data allows for the identification of water mass transport pathways and fine-scale structures, such as fronts, that drive surface distribution of tracers and microbial community structures.
Alain de Verneil, Louise Rousselet, Andrea M. Doglioli, Anne A. Petrenko, Christophe Maes, Pascale Bouruet-Aubertot, and Thierry Moutin
Biogeosciences, 15, 2125–2147,Short summary
Oceanographic campaigns to measure biogeochemical processes popularly deploy drifters with onboard incubations to stay in a single body of water. Here, we aggregate physical data taken during such a cruise, OUTPACE, to independently test in a new approach whether the drifter really stayed in what can be considered a single biological or chemical environment. This study concludes that future campaigns would benefit from similar data collection and analysis to validate their sampling strategy.
Susan L. Brantley, David M. Eissenstat, Jill A. Marshall, Sarah E. Godsey, Zsuzsanna Balogh-Brunstad, Diana L. Karwan, Shirley A. Papuga, Joshua Roering, Todd E. Dawson, Jaivime Evaristo, Oliver Chadwick, Jeffrey J. McDonnell, and Kathleen C. Weathers
Biogeosciences, 14, 5115–5142,Short summary
This review represents the outcome from an invigorating workshop discussion that involved tree physiologists, geomorphologists, ecologists, geochemists, and hydrologists and developed nine hypotheses that could be tested. We argue these hypotheses point to the essence of issues we must explore if we are to understand how the natural system of the earth surface evolves, and how humans will affect its evolution. This paper will create discussion and interest both before and after publication.
Johanne H. Rydsaa, Frode Stordal, Anders Bryn, and Lena M. Tallaksen
Biogeosciences, 14, 4209–4227,Short summary
We investigate the atmospheric sensitivity to an expansion in shrub and tree cover in the northern Fennoscandia region. We applied a regional weather and climate model in evaluating biophysical effects of increased shrub cover at a fine resolution. We find that shrub cover increase causes a warming that is sensitive to the shrub and tree heights. Cooling effects include increased snow cover, cloud cover, and precipitation. We show that the net warming will likely increase in the future.
Qian Cai, Yulong Zhang, Zhanxiang Sun, Jiaming Zheng, Wei Bai, Yue Zhang, Yang Liu, Liangshan Feng, Chen Feng, Zhe Zhang, Ning Yang, Jochem B. Evers, and Lizhen Zhang
Biogeosciences, 14, 3851–3858,Short summary
Large yield gaps exist in rain-fed maize in semi-arid regions caused by frequent droughts halfway through the growing period due to uneven distribution of rainfall. It can be questioned whether irrigation systems are economically and ecologically required. Maize yield was not affected by mild water stress due to the morphological plasticity in root growth. Our results help to mitigate drought risk in dry-land agriculture.
Jörg Schwinger, Jerry Tjiputra, Nadine Goris, Katharina D. Six, Alf Kirkevåg, Øyvind Seland, Christoph Heinze, and Tatiana Ilyina
Biogeosciences, 14, 3633–3648,Short summary
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.
Madhavan Girijakumari Keerthi, Matthieu Lengaigne, Marina Levy, Jerome Vialard, Vallivattathillam Parvathi, Clément de Boyer Montégut, Christian Ethé, Olivier Aumont, Iyyappan Suresh, Valiya Parambil Akhil, and Pillathu Moolayil Muraleedharan
Biogeosciences, 14, 3615–3632,Short summary
The northern Arabian Sea hosts a winter chlorophyll bloom, which exhibits strong interannual variability. The processes responsible for this interannual variation of the bloom are investigated using observations and a model. The interannual fluctuations of the winter bloom are largely related to the interannual mixed-layer depth (MLD) anomalies, which are driven by net heat flux anomalies. MLD controls the bloom amplitude through a modulation of nutrient turbulent fluxes into the mixed layer.
Lixin Lyu, Susanne Suvanto, Pekka Nöjd, Helena M. Henttonen, Harri Mäkinen, and Qi-Bin Zhang
Biogeosciences, 14, 3083–3095,Short summary
Our results reveal that the change in the tree growth–climate relationship is similar along latitudinal and altitudinal gradients, especially during growing seasons. Moreover, the critical periods for climatic effects on tree radial growth occurred earlier at lower latitudes and altitudes than at the cold ends of the gradients. We further demonstrate the use of daily climate data, as they may disclose more precise gradient patterns that could not be detected if monthly climate data were used.
Sophie Clayton, Stephanie Dutkiewicz, Oliver Jahn, Christopher Hill, Patrick Heimbach, and Michael J. Follows
Biogeosciences, 14, 2877–2889,
Xiang Gong, Wensheng Jiang, Linhui Wang, Huiwang Gao, Emmanuel Boss, Xiaohong Yao, Shuh-Ji Kao, and Jie Shi
Biogeosciences, 14, 2371–2386,Short summary
The subsurface chlorophyll maximum layer (SCML) forms near the nitracline. By incorporating a piecewise function for the approximate Gaussian vertical profile of chlorophyll, we derive analytical solutions of a specified nutrient–phytoplankton model. Nitracline depth is deeper than SCML depth, and a thinner SCML corresponds to a steeper nitracline. A higher light attenuation coefficient leads to a shallower but steeper nitracline. Nitracline steepness is independent of surface light intensity.
Johannes Karstensen, Florian Schütte, Alice Pietri, Gerd Krahmann, Björn Fiedler, Damian Grundle, Helena Hauss, Arne Körtzinger, Carolin R. Löscher, Pierre Testor, Nuno Vieira, and Martin Visbeck
Biogeosciences, 14, 2167–2181,Short summary
High-resolution observational data from underwater gliders and ships are used to investigate drivers and pathways of nutrient upwelling in high-productive whirling ecosystems (eddies). The data suggest that the upwelling is created by the interaction of wind-induced internal waves with the local rotation of the eddy. Because of differences in nutrient and oxygen pathways, a low-oxygen core is established at shallow depth in the high-productive eddies.
Parvathi Vallivattathillam, Suresh Iyyappan, Matthieu Lengaigne, Christian Ethé, Jérôme Vialard, Marina Levy, Neetu Suresh, Olivier Aumont, Laure Resplandy, Hema Naik, and Wajih Naqvi
Biogeosciences, 14, 1541–1559,Short summary
During late boreal summer and fall, the west coast of India (WCI) experiences hypoxia, which turns into anoxia during some years. We analyze a coupled physical–biogeochemical simulation over the 1960–2012 period to investigate the physical processes influencing oxycline interannual variability off the WCI. We show that fall WCI oxycline fluctuations are strongly related to Indian Ocean Dipole (IOD), with positive IODs preventing anoxia, while negative IODs do not necessarily result in anoxia.
Yonss Saranga José, Heiner Dietze, and Andreas Oschlies
Biogeosciences, 14, 1349–1364,Short summary
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.
Gerardo Arturo Sánchez-Azofeifa, J. Antonio Guzmán-Quesada, Mauricio Vega-Araya, Carlos Campos-Vargas, Sandra Milena Durán, Nikhil D'Souza, Thomas Gianoli, Carlos Portillo-Quintero, and Iain Sharp
Biogeosciences, 14, 977–988,Short summary
Lianas (woody vines) tend to respond positively to disturbance and show high densities in secondary forests. Lianas are a key component of tropical forests because they may reduce carbon potential. Identifying tools for liana detection is therefore essential for monitoring changes in tropical forests. In this study, we describe how terrestrial laser scanning can be used to detect the presence of lianas in forest stands of different ages in secondary tropical dry forests at a regional scale.
Maximilian Weigand and Andreas Kemna
Biogeosciences, 14, 921–939,Short summary
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.
Florent Domine, Mathieu Barrere, and Samuel Morin
Biogeosciences, 13, 6471–6486,Short summary
Warming-induced shrub growth in the Arctic traps snow and modifies snow properties, hence the permafrost thermal regime. In the Canadian high Arctic, we measured snow physical properties in the presence and absence of willow shrubs (Salix richardsonii). Shrubs dramatically reduce snow density and thermal conductivity, seriously limiting soil winter cooling. Simulations taking into account only winter changes show that shrub growth leads to a ground winter warming of up to 13 °C.
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Since current estimates show that only about 1 % of the all plastic that enters the ocean is floating at the surface, we look at subsurface processes that can cause vertical movement of (micro)plastic. We investigate how modelled algal attachment and the ocean's vertical movement can cause particles to sink and oscillate in the open ocean. Particles can sink to depths of > 5000 m in regions with high wind intensity and mainly remain close to the surface with low winds and biological activity.
Since current estimates show that only about 1 % of the all plastic that enters the ocean is...