ALBERT

Description: We present a workflow to estimate geostatistical aquifer parameters from pumping test data using the Python package welltestpy. The procedure of pumping test analysis is exemplified for two data sets from the Horkheimer Insel site and from the Lauswiesen site, Germany. The analysis is based on a semi‐analytical drawdown solution from the upscaling approach Radial Coarse Graining, which enables to infer log‐transmissivity variance and horizontal correlation length, beside mean transmissivity, and storativity, from pumping test data. We estimate these parameters of aquifer heterogeneity from type‐curve analysis and determine their sensitivity. This procedure, implemented in welltestpy, is a template for analyzing any pumping test. It goes beyond the possibilities of standard methods, for example, based on Theis' equation, which are limited to mean transmissivity and storativity. A sensitivity study showed the impact of observation well positions on the parameter estimation quality. The insights of this study help to optimize future test setups for geostatistical aquifer analysis and provides guidance for investigating pumping tests with regard to aquifer statistics using the open‐source software package welltestpy.

Description: Article impact statement: We present a workflow to infer parameters of subsurface heterogeneity from pumping test data exemplified at two sites using welltestpy.

Description: German Federal Environmental Foundation (DBU) http://dx.doi.org/10.13039/100007636

Description: In designed experiments, different sources of variability and an adequate scale of measurement need to be considered, but not all approaches in common usage are equally valid. In order to elucidate the importance of sources of variability and choice of scale, we conducted an experiment where the effects of biochar and slurry applications on soil properties related to soil fertility were studied for different designs: (a) for a field‐scale sampling design with either a model soil (without natural variability) as an internal control or with composited soils, (b) for a design with a focus on amendment variabilities, and (c) for three individual field‐scale designs with true field replication and a combined analysis representative of the population of loess‐derived soils. Three silty loam sites in Germany were sampled and the soil macroaggregates were crushed. For each design, six treatments (0, 0.15 and 0.30 g slurry‐N kg−1 with and without 30 g biochar kg−1) were applied before incubating the units under constant soil moisture conditions for 78 days. CO2 fluxes were monitored and soils were analysed for macroaggregate yields and associated organic carbon (C). Mixed‐effects models were used to describe the effects. For all soil properties, results for the loess sites differed with respect to significant contributions of fixed effects for at least one site, suggesting the need for a general inclusion of different sites. Analysis using a multilevel model allowed generalizations for loess soils to be made and showed that site:slurry:biochar and site:slurry interactions were not negligible for macroaggregate yields. The use of a model soil as an internal control enabled observation of variabilities other than those related to soils or amendments. Experiments incorporating natural variability in soils or amendments resulted in partially different outcomes, indicating the need to include all important sources of variability. Highlights Effects of biochar and slurry applications were studied for different designs and mixed‐effects models were used to describe the effects. Including an internal control allowed observation of, e.g., methodological and analytical variabilities. The results suggested the need for a general inclusion of different sites. Analysis using a multilevel model allowed generalizations for loess soils. The results indicated the need to include all important sources of variability.

Description: Temperate forest soils are often considered as an important sink for atmospheric carbon (C), thereby buffering anthropogenic CO2 emissions. However, the effect of tree species composition on the magnitude of this sink is unclear. We resampled a tree species common garden experiment (six sites) a decade after initial sampling to evaluate whether forest floor (FF) and topsoil organic carbon (Corg) and total nitrogen (Nt) stocks changed in dependence of tree species (Norway spruce—Picea abies L., European beech—Fagus sylvatica L., pedunculate oak—Quercus robur L., sycamore maple—Acer pseudoplatanus L., European ash—Fraxinus excelsior L. and small‐leaved lime—Tilia cordata L.). Two groups of species were identified in terms of Corg and Nt distribution: (1) Spruce with high Corg and Nt stocks in the FF developed as a mor humus layer which tended to have smaller Corg and Nt stocks and a wider Corg:Nt ratio in the mineral topsoil, and (2) the broadleaved species, of which ash and maple distinguished most clearly from spruce by very low Corg and Nt stocks in the FF developed as mull humus layer, had greater Corg and Nt stocks, and narrow Corg:Nt ratios in the mineral topsoil. Over 11 years, FF Corg and Nt stocks increased most under spruce, while small decreases in bulk mineral soil (esp. in 0–15 cm and 0–30 cm depth) Corg and Nt stocks dominated irrespective of species. Observed decadal changes were associated with site‐related and tree species‐mediated soil properties in a way that hinted towards short‐term accumulation and mineralisation dynamics of easily available organic substances. We found no indication for Corg stabilisation. However, results indicated increasing Nt stabilisation with increasing biomass of burrowing earthworms, which were highest under ash, lime and maple and lowest under spruce. Highlights We studied if tree species differences in topsoil Corg and Nt stocks substantiate after a decade. The study is unique in its repeated soil sampling in a multisite common garden experiment. Forest floors increased under spruce, but topsoil stocks decreased irrespective of species. Changes were of short‐term nature. Nitrogen was most stable under arbuscular mycorrhizal species.

Description: Deutsche Forschungsgemeinschaff (DFG)

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Malige, F., Patris, J., Buchan, S. J., Stafford, K. M., Shabangu, F., Findlay, K., Hucke-Gaete, R., Neira, S., Clark, C. W., & Glotin, H. Inter-annual decrease in pulse rate and peak frequency of Southeast Pacific blue whale song types. Scientific Reports, 10(1), (2020): 8121, doi:10.1038/s41598-020-64613-0.

Description: A decrease in the frequency of two southeast Pacific blue whale song types was examined over decades, using acoustic data from several different sources in the eastern Pacific Ocean ranging between the Equator and Chilean Patagonia. The pulse rate of the song units as well as their peak frequency were measured using two different methods (summed auto-correlation and Fourier transform). The sources of error associated with each measurement were assessed. There was a linear decline in both parameters for the more common song type (southeast Pacific song type n.2) between 1997 to 2017. An abbreviated analysis, also showed a frequency decline in the scarcer southeast Pacific song type n.1 between 1970 to 2014, revealing that both song types are declining at similar rates. We discussed the use of measuring both pulse rate and peak frequency to examine the frequency decline. Finally, a comparison of the rates of frequency decline with other song types reported in the literature and a discussion on the reasons of the frequency shift are presented.

Description: The authors thank the help of Explorasub diving center (Chile), Agrupación turística Chañaral de Aceituno (Chile), ONG Eutropia (Chile), Valparaiso university (Chile), the international institutions and research programs CTBTO, IWC, BRILAM STIC AmSud 17-STIC-01. S.J.B. thanks support from the Center for Oceanographic Research COPAS Sur-Austral, CONICYT PIA PFB31, Biology Department of Woods Hole Oceanographic Institution, the Office of Naval Research Global (awards N62909-16-2214 and N00014-17-2606), and a grant to the Centro de Estudios Avanzados en Zonas Ãridas (CEAZA) “Programa Regional CONICYT R16A10003”. We thank SABIOD MI CNRS, EADM MaDICS CNRS and ANR-18-CE40-0014 SMILES supporting this research. We are grateful to colleagues at DCLDE 2018 and SOLAMAC 2018 conferences for useful comments on the preliminary version of this work. In this work we used only the free and open-source softwares Latex, Audacity and OCTAVE.

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Sadai, S., Condron, A., DeConto, R., & Pollard, D. Future climate response to Antarctic Ice Sheet melt caused by anthropogenic warming. Science Advances, 6(39), (2020): eaaz1169, doi:10.1126/sciadv.aaz1169.

Description: Meltwater and ice discharge from a retreating Antarctic Ice Sheet could have important impacts on future global climate. Here, we report on multi-century (present–2250) climate simulations performed using a coupled numerical model integrated under future greenhouse-gas emission scenarios IPCC RCP4.5 and RCP8.5, with meltwater and ice discharge provided by a dynamic-thermodynamic ice sheet model. Accounting for Antarctic discharge raises subsurface ocean temperatures by 〉1°C at the ice margin relative to simulations ignoring discharge. In contrast, expanded sea ice and 2° to 10°C cooler surface air and surface ocean temperatures in the Southern Ocean delay the increase of projected global mean anthropogenic warming through 2250. In addition, the projected loss of Arctic winter sea ice and weakening of the Atlantic Meridional Overturning Circulation are delayed by several decades. Our results demonstrate a need to accurately account for meltwater input from ice sheets in order to make confident climate predictions.

Description: This research was supported by the NSF Office of Polar Programs through NSF grant 1443347, the Biological and Environmental Research (BER) division of the U.S. Department of Energy through grant DE-SC0019263, the NSF through ICER 1664013, and by a grant to the NASA Sea Level Science Team 80NSSC17K0698.

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ward, N. D., Megonigal, J. P., Bond-Lamberty, B., Bailey, V. L., Butman, D., Canuel, E. A., Diefenderfer, H., Ganju, N. K., Goni, M. A., Graham, E. B., Hopkinson, C. S., Khangaonkar, T., Langley, J. A., McDowell, N. G., Myers-Pigg, A. N., Neumann, R. B., Osburn, C. L., Price, R. M., Rowland, J., Sengupta, A., Simard, M., Thornton, P. E., Tzortziou, M., Vargas, R., Weisenhorn, P. B., & Windham-Myers, L. Representing the function and sensitivity of coastal interfaces in earth system models. Nature Communications, 11(1), (2020): 2458, doi:10.1038/s41467-020-16236-2.

Description: Between the land and ocean, diverse coastal ecosystems transform, store, and transport material. Across these interfaces, the dynamic exchange of energy and matter is driven by hydrological and hydrodynamic processes such as river and groundwater discharge, tides, waves, and storms. These dynamics regulate ecosystem functions and Earth’s climate, yet global models lack representation of coastal processes and related feedbacks, impeding their predictions of coastal and global responses to change. Here, we assess existing coastal monitoring networks and regional models, existing challenges in these efforts, and recommend a path towards development of global models that more robustly reflect the coastal interface.

Description: Funding for this work was provided by Pacific Northwest National Laboratory (PNNL) Laboratory Directed Research & Development (LDRD) as part of the Predicting Ecosystem Resilience through Multiscale Integrative Science (PREMIS) Initiative. PNNL is operated by Battelle for the U.S. Department of Energy under Contract DE-AC05-76RL01830. Additional support to J.P.M. was provided by the NSF-LTREB program (DEB-0950080, DEB-1457100, DEB-1557009), DOE-TES Program (DE-SC0008339), and the Smithsonian Institution. This manuscript was motivated by discussions held by co-authors during a three-day workshop at PNNL in Richland, WA: The System for Terrestrial Aquatic Research (STAR) Workshop: Terrestrial-Aquatic Research in Coastal Systems. The authors thank PNNL artist Nathan Johnson for preparing the figures in this manuscript and Terry Clark, Dr. Charlette Geffen, and Dr. Nancy Hess for their aid in organizing the STAR workshop. The authors thank all workshop participants not listed as authors for their valuable insight: Lihini Aluwihare (contributed to biogeochemistry discussions and development of concept for Fig. 3), Gautam Bisht (contributed to modeling discussion), Emmett Duffy (contributed to observational network discussions), Yilin Fang (contributed to modeling discussion), Jeremy Jones (contributed to biogeochemistry discussions), Roser Matamala (contributed to biogeochemistry discussions), James Morris (contributed to biogeochemistry discussions), Robert Twilley (contributed to biogeochemistry discussions), and Jesse Vance (contributed to observational network discussions). A full report on the workshop discussions can be found at https://www.pnnl.gov/publications/star-workshop-terrestrial-aquatic-research-coastal-systems.

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Liang, Y., Lo, M., Lan, C., Seo, H., Ummenhofer, C. C., Yeager, S., Wu, R., & Steffen, J. D. Amplified seasonal cycle in hydroclimate over the Amazon river basin and its plume region. Nature Communications, 11(1), (2020): 4390, doi:10.1038/s41467-020-18187-0.

Description: The Amazon river basin receives ~2000 mm of precipitation annually and contributes ~17% of global river freshwater input to the oceans; its hydroclimatic variations can exert profound impacts on the marine ecosystem in the Amazon plume region (APR) and have potential far-reaching influences on hydroclimate over the tropical Atlantic. Here, we show that an amplified seasonal cycle of Amazonia precipitation, represented by the annual difference between maximum and minimum values, during the period 1979–2018, leads to enhanced seasonalities in both Amazon river discharge and APR ocean salinity. An atmospheric moisture budget analysis shows that these enhanced seasonal cycles are associated with similar amplifications in the atmospheric vertical and horizontal moisture advections. Hierarchical sensitivity experiments using global climate models quantify the relationships of these enhanced seasonalities. The results suggest that an intensified hydroclimatological cycle may develop in the Amazonia atmosphere-land-ocean coupled system, favouring more extreme terrestrial and marine conditions.

Description: M.-H.L., C.-W.L., and R.-J.W. are supported by the Ministry of Science and Technology in Taiwan under grant 106-2111-M-002-010-MY4. H.S. and J.D.S. are grateful for support from NOAA NA19OAR4310376 and NA17OAR4310255. C.C.U. acknowledges support from the U.S. National Science Foundation under grant OCE-1663704. The National Center for Atmospheric Research (NCAR) is a major facility sponsored by the US National Science Foundation (NSF) under Cooperative Agreement No. 1852977. We thank Dr. Young-Oh Kwon at Woods Hole Oceanographic Institution and Dr. Who Kim at NCAR for discussions about the ocean model experiment design. We thank Dr. Mehnaz Rashid at National Taiwan University and Wen-Yin Wu at the University of Texas at Austin in helping generate the high-resolution Amazon river mask. We also thank Dr. Gael Forget at Massachusetts Institue of Technology for comments on using ECCO and other ocean-state estimate products.

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gravinese, P. M., Page, H. N., Butler, C. B., Spadaro, A. J., Hewett, C., Considine, M., Lankes, D., & Fisher, S. Ocean acidification disrupts the orientation of postlarval Caribbean spiny lobsters. Scientific Reports, 10(1), (2020): 18092, doi:10.1038/s41598-020-75021-9.

Description: Anthropogenic inputs into coastal ecosystems are causing more frequent environmental fluctuations and reducing seawater pH. One such ecosystem is Florida Bay, an important nursery for the Caribbean spiny lobster, Panulirus argus. Although adult crustaceans are often resilient to reduced seawater pH, earlier ontogenetic stages can be physiologically limited in their tolerance to ocean acidification on shorter time scales. We used a Y-maze chamber to test whether reduced-pH seawater altered the orientation of spiny lobster pueruli toward chemical cues produced by Laurencia spp. macroalgae, a known settlement cue for the species. We tested the hypothesis that pueruli conditioned in reduced-pH seawater would be less responsive to Laurencia spp. chemical cues than pueruli in ambient-pH seawater by comparing the proportion of individuals that moved to the cue side of the chamber with the proportion that moved to the side with no cue. We also recorded the amount of time (sec) before a response was observed. Pueruli conditioned in reduced-pH seawater were less responsive and failed to select the Laurencia cue. Our results suggest that episodic acidification of coastal waters might limit the ability of pueruli to locate settlement habitats, increasing postsettlement mortality.

Description: We thank the Steinwachs Family Foundation, which provided funding that supported Gravinese’s postdoctoral fellowship at Mote Marine Laboratory and Aquarium. We also acknowledge the partial support provided by the St. Petersburg College Titan Achievement minigrant program. Page was supported by a Mote Marine Laboratory and Aquarium Postdoctoral Research Fellowship. Postlarval spiny lobsters were collected with a state-issued Special Activity License (SAL-17-1868G-SR). We also thank those who helped with animal collection throughout this work including in-kind support provided by E. Muller and the Mote CAOS facility, as well as E. Bartels and C. Walter of the Coral Reef Monitoring and Assessment Program at Mote Marine Laboratory and Aquarium, as well as other field personnel including: L. Toth, S. Perry, T. Parker, A. Fine, L. Humphrey, and many undergraduate interns. We also thank L. Toth, E. Ross, B. Sharp, C. Crowley, J. Butler, and B. Crowder for editorial comments.

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Huang, J., Pickart, R. S., Huang, R. X., Lin, P., Brakstad, A., & Xu, F. Sources and upstream pathways of the densest overflow water in the Nordic Seas. Nature Communications, 11(1), (2020): 5389, doi:10.1038/s41467-020-19050-y.

Description: Overflow water from the Nordic Seas comprises the deepest limb of the Atlantic Meridional Overturning Circulation, yet questions remain as to where it is ventilated and how it reaches the Greenland-Scotland Ridge. Here we use historical hydrographic data from 2005-2015, together with satellite altimeter data, to elucidate the source regions of the Denmark Strait and Faroe Bank Channel overflows and the pathways feeding these respective sills. A recently-developed metric is used to calculate how similar two water parcels are, based on potential density and potential spicity. This reveals that the interior of the Greenland Sea gyre is the primary wintertime source of the densest portion of both overflows. After subducting, the water progresses southward along several ridge systems towards the Greenland-Scotland Ridge. Kinematic evidence supports the inferred pathways. Extending the calculation back to the 1980s reveals that the ventilation occurred previously along the periphery of the Greenland Sea gyre.

Description: Funding for the study was provided by the US National Science Foundation under grants OCE-1558742 (J.H., R.P.) and OCE-1259618 (P.L.); the Bergen Research Foundation under grant BFS2016REK01 (A.B.); and the National Natural Science Foundation of China No. 41576018 (F.X.) and 41606020 (F.X.).

Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Colin, S. P., Costello, J. H., Sutherland, K. R., Gemmell, B. J., Dabiri, J. O., & Du Clos, K. T. The role of suction thrust in the metachronal paddles of swimming invertebrates. Scientific Reports, 10(1), (2020): 17790, doi:10.1038/s41598-020-74745-y.

Description: An abundance of swimming animals have converged upon a common swimming strategy using multiple propulsors coordinated as metachronal waves. The shared kinematics suggest that even morphologically and systematically diverse animals use similar fluid dynamic relationships to generate swimming thrust. We quantified the kinematics and hydrodynamics of a diverse group of small swimming animals who use multiple propulsors, e.g. limbs or ctenes, which move with antiplectic metachronal waves to generate thrust. Here we show that even at these relatively small scales the bending movements of limbs and ctenes conform to the patterns observed for much larger swimming animals. We show that, like other swimming animals, the propulsors of these metachronal swimmers rely on generating negative pressure along their surfaces to generate forward thrust (i.e., suction thrust). Relying on negative pressure, as opposed to high pushing pressure, facilitates metachronal waves and enables these swimmers to exploit readily produced hydrodynamic structures. Understanding the role of negative pressure fields in metachronal swimmers may provide clues about the hydrodynamic traits shared by swimming and flying animals.

Description: This work was funded by National Science Foundation (NSF OCE 1829913 to SPC), the Alfred P. Sloan Foundation (to BJG) and the Gordon and Betty Moore Foundation (8835 to KRS). The work was also supported by the Roger Williams Foundation to Promote Scholarship and Teaching.