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: 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.

Description: PCM00-78 box (C) and Kasten (KII-IV) cores were taken in the San Lazaro Basin (SLB) (sometimes referred to as the Soledad Basin) at (25° 10'N, 112° 45'W). The SLB is a suboxic fault-bounded basin 50 km offshore of the Baja California peninsula, with a surface area of ~3000 km2 and a water depth of 540 m. Weak-to-absent bioturbation promotes the preservation of laminated sediments, facilitating high-resolution SST reconstruction. Box core PCM00-78C was stratigraphically tied to Kasten core PCM00-KI via natural Pb decay and reconstructed SST measurements are reported here on a composite depth scale covering all sediment cores. Additional age control is provided by 137Cs and radiocarbon measurements (see manuscript for further details).

Description: Coccolithophore productivity and surface water dynamics for the last 25 kyr in the Alboran Sea (Western Mediterranean) are described in a study of high-resolution sedimentary records from two cores, HER-GC-T1 and CEUTA10PC08, whose locations are currently characterized by different hydrographic conditions. Fossil coccolithophore assemblages and oxygen isotopes and alkenone- and planktonic foraminifera-derived sea surface temperature (SST) records allowed a reconstruction of the properties of the inflowing Atlantic Water (AW), which have proved to be a primary control of the variations in productivity in the neighborhood of the Strait of Gibraltar. Other local factors, such as fluvial discharge, wind-induced and eddy-induced upwelling, are proposed to have influenced marine productivity in more distant areas. The entrance of cold and less saline AW during the stadials associated with Heinrich events 2 and 1 prevented primary productivity, which increased along the Last Glacial Maximum, probably due to a greater fluvial discharge. During Terminations 1a and 1b, the upper water column was affected by stratification, although wind-induced upwelling occurred locally. The Bølling–Allerød was characterized by a gradual increase in productivity and the development of the organic-rich layer. Two phases of the Younger Dryas are recognized: a first phase, which was colder, followed by a second phase, which was warmer and wetter. Differences in productivity between both locations during these two phases can be attributed to fluvial discharge and the changing properties of the AW. Local hydrography, such as the dynamics of the western anticyclonic gyre, gained greater importance in determining productivity and its variations during the Holocene, which was the most productive period.

Description: The Humboldt Current System (HCS) has the highest production of forage fish in the world, although it is highly variable and the future of the primary component, anchovy, is uncertain in the context of global warming. Paradigms based on late 20th century observations suggest that large-scale forcing controls decadal-scale fluctuations of anchovy and sardine across different boundary currents of the Pacific. We develop records of anchovy and sardine fluctuations since 1860 AD using fish scales from multiple sites containing laminated sediments and compare them with Pacific basin-scale and regional indices of ocean climate variability. Our records reveal two main anchovy and sardine phases with a timescale that is not consistent with previously proposed periodicities. Rather, the regime shifts in the HCS are related to 3D habitat changes driven by changes in upwelling intensity from both regional and large-scale forcing. Moreover, we show that a long-term increase in coastal upwelling translates via a bottom-up mechanism to top predators suggesting that the warming climate, at least up to the start of the 21st century, was favorable for fishery productivity in the HCS.