ALBERT

Description: Between 14.03.2006 and 25.04.2006, bathymetric data based on the KONGSBERG EM710 system (MBES) was acquired in the Gulf of Mexico during the R/V METEOR cruise M67/2. The main research goal was the investigation of asphalt volcanoes in the Campeche Bay and related sedimentary structures. The leg was split into two parts. During the first sub-leg 2a geophysical and especially hydroacoustic methods were used to explore the distribution of these asphalt volcanoes and to map knolls as well as other structures like mass wasting and asphalt flows. Using reflection seismic, sedimentary structures related to the volcanoes were also investigated. Further mapping but also sampling of vent fluids and asphalt was the research interest of sub-leg 2b. Therefore the Remotely Operating Vehicle (ROV) QUEST (Marum) as well as a TV-MUC were used. Bathymetry mapping was done using the EM120 for deeper and the EM710 for shallower regions. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the M67/2 cruise, the hull-mounted multibeam echosounder (MBES) KONGSBERG EM710 was utilized to perform bathymetric mapping in shallower areas. It allows to conduct surveys in water depths of up to 2,000 m, however it operates best in shallower water depths under 500 m. Two transducer arrays transmit frequency coded acoustic signals (70 to 100 kHz). Data acquisition is based on continuous wave pulses in shallower depths and FM (chirp) pulses in greater depths. The beam footprint has a dimension of 1° by 1°. For further information on the system, consult: https://www.km.kongsberg.com/ Due to the water depth of the research area the EM120 was permanently used, while the EM710 was only used in few parts of the research area. To convert the recorded travel times into water depth, several sound velocity profiles were obtained with the shipboard CTD, providing a correction for ray bending for each beam. Depth is estimated from each beam by using the two-way travel time and the known beam angle known, and taking into account the ray bending due to refraction in the water column by sound speed variations. Responsible person during this cruise / PI: Volkhard Spieß (vspiess uni-bremen.de), Gerhard Bohrmann (gbohrmann@marum.de) Chief Scientist: : Volkhard Spieß (vspiess uni-bremen.de), Gerhard Bohrmann (gbohrmann@marum.de) CR: https://www.tib.eu/de/suchen/id/awi%3Adoi~10.2312%252Fcr_m67/ CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2006/20060077.htm

Description: Here, we present 23 water physical (temperature, dissolved oxygen, pH, conductivity) and chemical (major anions Cl-, SO42-, CO32-, HCO3- and cations Ca2+, K+, Mg2+, Na+), sedimentological (total carbon (TC), total inorganic carbon (TIC), total organic carbon (TOC), total nitrogen (TN)), mineralogical (quartz, carbonate, phyllosilicates and feldspars) and geological (altitude, bedrock type and age of sediments) variables of aquatic systems of the Northern Neotropical region. Sampling was conducted in 76 aquatic systems during July-October 2013, coinciding with the rainy season in the region. Sampling sites are located on the Yucatán Peninsula Mexico (n=28), Guatemala (n=26), El Salvador (n=14), Honduras (n=5) and Nicaragua (n=3). We aim to identify limnological regions based on the measured variables and to infer the influence of geodiversity in observed patterns. Water physical and chemical variables were measured in situ with a WTW Multi Set 350i multiparameter probe at a water depth of 0.5 m. Water samples for analysis of major anions and cations were collected at water depths of 0.5 m below surface. TC and TN in sediments contents were determined by combustion with a LECO TruSpec Macro CHN analyzer. TIC was quantified with a Woesthoff Carmhograph C-16. TOC was calculated by subtracting TIC from TC. Qualitative and semi-quantitative mineralogical compounds were examined by x-ray diffraction with a RIGAKU Miniflex600. ArcGIS software was used to identify geological attributes of sampling sites such as bedrock and age of sediments. Altitude, latitude, and longitude were determined with the navigator Garmin GPSmap 60c.

Description: Biomass accumulation was assessed by subtracting phytoplankton mortality (due to microzooplankton) from phytoplankton growth rates. Rates of phytoplankton growth and microzooplankton grazing were assessed daily with the dilution technique (Landry and Hassett 1982; doi:10.1007/BF00397668), following the two treatment approach (Landry, Haas et al. 1984 doi:10.3354/meps016127), at six depths within the euphotic zone. We implemented this mini-dilution approach to generate vertically resolved growth and grazing rates, but also conducted a full dilution experiment on the last day of each of the cycles (n = 5) to test linearity assumptions of the method. Seawater collected with the Niskin bottles attached to the CTD rosette at 02:00 h was used to fill a pair of 2.2-L polycarbonate bottles (100%, B and C) while a third bottle (A) was filled with 25% whole seawater diluted with 0.2-µm filtered seawater obtained immediately before by gravity filtration using an Acropak filter cartridge (Pall) directly from the same Niskin bottle. Nutrients (final concentrations in 2.2L bottles; nitrate 0.18 μM, ammonium 4.16 μM, phosphate 15.08, silicate 44.2 μM, and vitamins) were added to bottles A and B in order to ensure the assumption that the same phytoplankton intrinsic growth rate was occurring in WSW and FSW bottles despite dilution (Gutiérrez‐Rodríguez, Safi et al. 2020 doi:10.1029/2019JC015550). Bottles were then incubated in situ at the same six depths of collection using a drifting array. Rates were calculated from changes in Chl a concentration and picophytoplankton abundance between the beginning and end of the experiment assuming exponential growth of phytoplankton. Microzooplankton grazing rate was estimated from: µ = (kA – kB)/(1-x) where kA and kB are the observed net rates of change of chl a in bottles A and B, respectively, and x is the fraction of whole seawater in the diluted bottle A (0.25). Phytoplankton growth rate was estimated from µ =m+kB. Photoacclimation effects were corrected from changes in cell chl a fluorescence estimated by flow cytometry during incubations as a proxy of cell chl a content (Gutierrez-Rodriguez, Latasa et al. 2010 doi:10.1016/j.dsr.2009.12.013). These include estimating the photoacclimation index (Phi) from changes in FL3: FSC and calculating an average value from Phi index obtained for pico- and nanoeukaryotic populations weighted by their biomass contribution. Accumulation was calculated by subtracting the C-based estimates of microzooplankton grazing (from the dilution experiments) from the 14C-based NPP.

Description: We reconstructed a high-resolution, alkenone-based sea surface temperature (SST) record spanning the last ca. 150 years, from a sediment core retrieved within the main upwelling zone off Peru. A conspicuous SST decline is evidenced since the 1950s despite interdecadal SST variability. Instrumental SST data and reanalysis of ECMWF ERA 40 winds suggest that the recent coastal cooling corresponds mainly to an intensification of alongshore winds and associated increase of upwelling in spring. Consistently, both proxy and instrumental data evidence increased productivity in phase with the SST cooling. Our data expand on previous reports on recent SST cooling in other Eastern Boundary upwelling systems and support scenarios that relate coastal upwelling intensification to global warming. Yet, further investigations are needed to assess the role of different mechanisms and forcings (enhanced local winds vs. spin-up of the South Pacific High Pressure cell).

Description: Salps were collected using double oblique Bongo tows, with 0.7m diameter frames equipped with 202 µm nets, General Oceanics flow meters, and an RBR temperature depth recorder. Salp specimens (typically 10) from each tow had their guts excised, and chl a and phaeopigments gut contents were measured. A power function was used to fit the size-specific Gpig (chl a + phaeo) contents for each tow, allowing the estimation of Gpig for each size bin per tow, and this was multiplied by the abundance in each size bin. Gut passage time (GPT) was calculated using a modified equation, based on (von Harbou, Dubischar et al. 2011 doi:10.1007/s00227-011-1709-4) where GPT(h) = 2.607*ln(OAL, mm) - 2.6. Grazing was estimated as: G (h-1) = Gpig /GPT, and scaled using a Q10=2. Daily salp grazing rates were obtained by assuming 14 h of day and 10 h of night, coincident with the times and latitudes at which we sampled these communities during the Salp Particle expOrt and Ocean Production (SalpPOOP) campaign. Cycle estimates were calculated by first averaging all day and all night tows separately, and then adding the two estimates. Fecal pellet production was calculated by assuming an egestion efficiency of 0.36 (Huntley, Sykes et al. 1989 doi:10.1007/BF00238291, Pakhomov 2004 doi:10.1016/j.dsr2.2001.03.001, Pakhomov and Froneman 2004 10.1016/j.dsr2.2000.11.002) and converting to carbon values using C:Chl ratios from the phytoplankton growth and grazing experiments combined with NPP, and reported in mg C m-2 d-1. Data is reported by size after binning in 5mm size bins (ranging 1-135mm), and for oozooids and blastozooids separately.

Description: Water collection for nutrient analysis was done using a CTD rosette equipped with 24 10L Niskin bottles, at different depths throughout the water column depending on the cast, spanning the euphotic zone to a maximum depth of 200m. Multiple casts were done during five Lagrangian experimental cycles conducted during Salp Particle expOrt and Ocean Production (SalpPOOP), from October to November 2018 in the vicinity of the Chatham Rise (New Zealand). Water was filtered through 25mm Whatman GF/F filters onto clean polyethylene bottles (250ml) and frozen at -20 °C. Analysis was done at the NIWA Hamilton Water Quality Laboratory (New Zealand), using an Astoria Pacific API 300 microsegmented flow analyzer (Astoria-Pacific, Clackamas, OR, United States) following colorimetric the methods outlined in Law et al. (2011; doi:10.1016/j.dsr2.2010.10.018).

Description: Quantifying soil erosion rates (ERs) in developing countries is necessary to accomplish the Goal 15 of the UN 2030 Agenda for Sustainable Development and is relevant to meet the technical challenges of future hyperresolution models. This study proposes using the RUSLE model on the basis of the Generalized Likelihood Uncertainty Estimation (GLUE) methodology to estimate ERs at country scale for developing countries, which commonly exhibit spatio-temporal limitations/lack of groundbased measurements or field relations potentially inducing high uncertainty in the estimates of the R and C factors. In this context, ERs are calibrated with area-specific sediment yield data and global soil erosion model outputs. The method is successfully applied to Peru, and subsequently 5-km resolution ER maps are obtained for the years 1990, 2000, and 2010 which suggest that the steady increase of soil erosion rates are mainly induced by anthropogenic controls (e.g. changes in land use). In the light of our results, we believe that the method has the potential to be used as a standard method to estimate ERs and provide decision makers for an objective information to better manage soil resources in developing countries.

Description: Our main objectives in this study were: (1) identify areas with high herb-shrub species richness derived from Species Distribution Models (SDMs) and (2) delineate phytogeographic regions for the Cerrado based on floristic similarities in the herb-shrub flora. Using a large dataset of herb-shrub species collection records and inventories data combined with spatial abiotic data through SDMs, we reached conclusions about patterns of species richness, phytogeographic regions and conservation priority areas for the herb-shrub flora of the Cerrado. The zip file contains: 1) Amaral_et_al_2017_richness.tif - Richness pattern of the Cerrado herb-shrub flora based on species distribution models (SDMs). 2) Amaral_et_al_2017_phytoregions.tif - Modelled nine phytogeographic regions for the herb-shrub flora of the Cerrado.

Description: Bedforms Analysis Toolkit for Multiscale Modeling (Bedforms-ATM) is an open source MATLAB software which is aimed to standardize the analysis of variability of bed forms. Bedforms-ATM can be downloaded from the following link: https://sourceforge.net/projects/bedforms-atm/ Two types of data accompany Bedforms-ATM, namely: [1] Bed form data from the Parana River (Argentina), which comprises 150 bed form profiles, and [2] Synthetic bed form fields for both rectangular and curved bed form fields. This contribution comprises the latter data, which includes data from both curved plots and a rectangular plots. The synthetic bed forms fields were built by using the mathematical definitions presented by Gutierrez et al, 2013 and Gutierrez & Abad, 2014. Curved bed form fields comprise stretches having sinuosities of 1.1, 1.5, 2.0, 2.5, 3.5, 4.0, 4.5, 5.0, 5.5. The largest file size (〉 100MB) corresponds to the synthetic rectangular bed form field.