Do Shapes of Elevational Gradients of Species Richness Depend on the Vertical Range Studied? The Case of the Himalayas

We retrieved shapes of elevational species richness gradients (unimodal, decreasing, increasing) from 64 publications, studying Himalayan elevation patterns. We covered both plants and animals, and tested the hypothesis that unimodal gradients, explicable by the geometric mid-domain effect, prevail in the mountains, whereas decreasing or increasing gradients result from studying only short sections of entire altitudinal ranges. Multivariate canonical correspondence analysis was used to relate gradient shapes to their altitude ranges, geography positions, and taxa studied. Across taxa, most of the Himalayan altitudinal gradient display a unimodal shape, with a peak of diversity situated at ca 2500 m a.s.l. for plants, and 2200 m a.s.l. for animals. The gradient shapes were attributable to three intercorrelated predictors: vertical range, maximum elevation, and mean elevation of the gradients. Studies covering sufficiently broad altitudinal range returned unimodal gradients. Studies from the Earth’s highest mountain range reveal that surveys covering substantial parts of the elevational range of the mountains result in unimodal elevational gradients, whereas declining or increasing species richness gradients result from incomplete elevation range sampling.

Toward a Solution of the “Peruvian Puzzle”: Pelagic Food-Web Structure and Trophic Interactions in the Northern Humboldt Current Upwelling System Off Peru

The northern Humboldt Current upwelling system (HCS) belongs to the most productive marine ecosystems, providing five to eight times higher fisheries landings per unit area than other coastal upwelling systems. To solve this “Peruvian puzzle”, to elucidate the pelagic food-web structure and to better understand trophic interactions in the HCS, a combined stable isotope and fatty acid trophic biomarker approach was adopted for key zooplankton taxa and higher trophic positions with an extensive spatial coverage from 8.5 to 16°S and a vertical range down to 1,000 m depth. A pronounced regional shift by up to ∼5‰ in the δ15N baseline of the food web occurred from North to South. Besides regional shifts, δ15N ratios of particulate organic matter (POM) also tended to increase with depth, with differences of up to 3.8‰ between surface waters and the oxygen minimum zone. In consequence, suspension-feeding zooplankton permanently residing at depth had up to ∼6‰ higher δ15N signals than surface-living species or diel vertical migrants. The comprehensive data set covered over 20 zooplankton taxa and indicated that three crustacean species usually are key in the zooplankton community, i.e., the copepods Calanus chilensis at the surface and Eucalanus inermis in the pronounced OMZ and the krill Euphausia mucronata, resulting in an overall low number of major trophic pathways toward anchovies. In addition, the semi-pelagic squat lobster Pleuroncodes monodon appears to play a key role in the benthic-pelagic coupling, as indicated by highest δ13C’ ratios of −14.7‰. If feeding on benthic resources and by diel vertical migration, they provide a unique pathway for returning carbon and energy from the seafloor to the epipelagic layer, increasing the food supply for pelagic fish. Overall, these mechanisms result in a very efficient food chain, channeling energy toward higher trophic positions and partially explaining the “Peruvian puzzle” of enormous fish production in the HCS.

Quantitative Precipitation Estimation over Antarctica Using Different Ze-SR Relationships Based on Snowfall Classification Combining Ground Observations

Snow plays a crucial role in the hydrological cycle and energy budget of the Earth, and remote sensing instruments with the necessary spatial coverage, resolution, and temporal sampling are essential for snowfall monitoring. Among such instruments, ground-radars have scanning capability and a resolution that make it possible to obtain a 3D structure of precipitating systems or vertical profiles when used in profiling mode. Radars from space have a lower spatial resolution, but they provide a global view. However, radar-based quantitative estimates of solid precipitation are still a challenge due to the variability of the microphysical, geometrical, and electrical features of snow particles. Estimations of snowfall rate are usually accomplished using empirical, long-term relationships between the equivalent radar reflectivity factor (Ze) and the liquid-equivalent snowfall rate (SR). Nevertheless, very few relationships take advantage of the direct estimation of the microphysical characteristics of snowflakes. In this work, we used a K-band vertically pointing radar collocated with a laser disdrometer to develop Ze-SR relationships as a function of snow classification. The two instruments were located at the Italian Antarctic Station Mario Zucchelli. The K-band radar probes the low-level atmospheric layers, recording power spectra at 32 vertical range gates. It was set at a high vertical resolution (35 m), with the first trusted range gate at a height of only 100 m. The disdrometer was able to provide information on the particle size distribution just below the trusted radar gate. Snow particles were classified into six categories (aggregate, dendrite aggregate, plate aggregate, pristine, dendrite pristine, plate pristine). The method was applied to the snowfall events of the Antarctic summer seasons of 2018–2019 and 2019–2020, with a total of 23,566 min of precipitation, 15.3% of which was recognized as showing aggregate features, 33.3% dendrite aggregate, 7.3% plates aggregate, 12.5% pristine, 24% dendrite pristine, and 7.6% plate pristine. Applying the appropriate Ze-SR relationship in each snow category, we calculated a total of 87 mm water equivalent, differing from the total found by applying a unique Ze-SR. Our estimates were also benchmarked against a colocated Alter-shielded weighing gauge, resulting in a difference of 3% in the analyzed periods.

The ESA MIPAS/Envisat level2-v8 dataset: 10 years of measurements retrieved with ORM v8.22

The observations acquired during the full mission of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument, aboard the European Space Agency Environmental Satellite (Envisat), have been analysed with version 8.22 of the Optimised Retrieval Model (ORM), originally developed as the scientific prototype of the ESA level-2 processor for MIPAS observations. The results of the analyses have been included into the MIPAS level-2 version 8 (level2-v8) database containing atmospheric fields of pressure, temperature, and volume mixing ratio (VMR) of MIPAS main targets H2O, O3, HNO3, CH4, N2O, and NO2, along with the minor gases CFC-11, ClONO2, N2O5, CFC-12, COF2, CCl4, CF4, HCFC-22, C2H2, CH3Cl, COCl2, C2H6, OCS, and HDO. The database covers all the measurements acquired by MIPAS in the nominal measurement mode of the full resolution (FR) part of the mission (from July 2002 to March 2004) and all the observation modes of the optimised resolution (OR) part (from January 2005 to April 2012). The number of species included in the MIPAS level2-v8 dataset makes it of particular importance for the studies of stratospheric chemistry. The database is considered by ESA the final release of the MIPAS level-2 products. The ORM algorithm is operated at the vertical grid coincident to the tangent altitudes of the observations or to a subset of them, spanning (in the nominal mode) the altitude range from 6 to 68 km in the FR phase and from 6 to 70 km in the OR period. In the latitude domain, FR profiles are spaced by about 4.7∘, while the OR profiles are spaced by about 3.7∘. For each retrieved species, the auxiliary data and the retrieval choices are described. Each product is characterised in terms of the retrieval error, spatial resolution, and “useful” vertical range in both phases of the MIPAS mission. These depend on the characteristics of the measurements (spectral and vertical resolution of the measurements), the retrieval choices (number of spectral points included in the analyses, number of altitudes included in the vertical retrieval grid), and the information content of the measurements for each trace species. For temperature, water vapour, ozone, and nitric acid, the number of degrees of freedom is significantly larger in the OR phase than in the FR one, mainly due to the finer vertical measurement grid. In the FR phase, some trace species are characterised by a smaller retrieval error with respect to the OR phase, mainly due to the larger number of spectral points used in the analyses, along with the reduced vertical resolution. The way of handling possible caveats (negative VMR, vertical grid representation) is discussed. The quality of the retrieved profiles is assessed through four criteria, two providing information on the successful convergence of the retrieval iterations, one on the capability of the retrieval to reproduce the measurements, and one on the presence of outliers. An easy way to identify and filter the problematic profiles with the information contained in the output files is provided. MIPAS level2-v8 data are available to the scientific community through the ESA portal (https://doi.org/10.5270/EN1-c8hgqx4).

On genesis of massive sulfide polymetallic ore deposits of Rudny Altai

Many geologists assign most of large- and medium-sized massive sulfide polymetallic ore deposits of Eastern Kazakhstan to the VMS type. These ore deposits formed in the Devonian, under conditions of rifting and active basalt-andesite-rhyolite volcanism. Ore bodies of these deposits are noted to be clearly confined to formations of several geochronologic levels (D1e to D3fm). Hydrothermal-sedimentary syngenetic and hydrothermal-metasomatic ores are distinguished. High concentrations of base metals in the ores (above 10 % sum metals) and their rather simple mineral composition (chalcopyrite, pyrite, galena, and sphalerite) are a characteristic feature of all the massive sulfide polymetallic ore deposits of Rudny Altai. The ores are noted to be multicomponental, with elevated contents of the admixtures of precious metals and rare elements (Cd, Se, Bi, Te, Ta, W, etc.). Mineralogical investigations of the ores have demonstrated an intricate relationships of the major ore minerals (chalcopyrite, pyrite, sphalerite, galena) that exhibit several generations and different geochemical specialization. Minerals of Au, Ag, Te, Bi, and other elements are encountered as individual grains or microscopic inclusions and stringers in minerals of Cu, Pb, and Zn. A significant vertical range of the ore mineralization (more than 100 m), the complexity and long duration of the ore-forming processes, the clearly defined confinement of the ore mineralization to certain geochronologic levels, – all these allow us to suppose a possibility of discovery of new ore lodes or individual ore deposits within the already known ore fields of the Kazakhstan segment of Rudny Altai

Scavenging amphipods of the Tonga Trench: an analysis of community assemblage and population structure

<p>The hadal zone is the common name for the deepest section of the ocean (6,000-11,000 m depth). It encompasses 45 % of the ocean’s depth range, and is mostly represented by oceanic trenches. Trench habitats lack sufficient sampling and the communities within are not well understood. Often, samples are derived from a single depth and thus the population dynamics of trench communities have not been analysed comprehensively. Scavenging amphipods are abundant and diverse taxa in the trench environment, and have been found in every trench sampled to date. They rapidly intercept and consume carrion falls at the deepest trench depths, and act as key prey items to predators in the shallower depths of the hadal zone. There appears to be a relationship of increasing abundance and decreasing diversity of scavenging amphipods with depth. However in the Tonga Trench, sampling of hadal amphipods has been limited, and these patterns remain unclear. The QUELLE (Quest for the Limit of Life) project in 2013 was led by The Japan Agency for Marine-Earth Science and Technology (JAMSTEC). As part of this project, the YOK 13-10 voyage examined scavenging amphipods in the Tonga Trench. The voyage used baited traps to sample depths of ˜6,250 m and ˜10,800 m from October 6 – October 21 in 2013. The main objectives of the present study were to: identify scavenging amphipod assemblages within the Tonga Trench and compare them to other trenches of the South Pacific; analyse the population structure of Hirondellea dubia between depths in the Tonga Trench; and identify a suitable total length proxy for H. dubia. Six species of amphipods were identified from depths of ˜6,250 m and ˜10,800 m in the Tonga Trench. At ˜6,250 m Alicella gigantea, Eurythenes gryllus, H. dubia, Bathycallisoma schellenbergi, an alicellid species, and a gammarid species were recovered. In contrast, H. dubia was the only species recovered from ˜10,800 m. The abundance of amphipods was higher at the ˜10,800 m site while the diversity was much lower. The assemblage of scavenging amphipods in the Tonga Trench was similar to those from past sampling efforts in the same trench. There were also similarities to the assemblages in the adjacent Kermadec Trench, and together these observations support the classification of these two trenches as a single biogeographic province. The assemblages in the Peru-Chile Trench in the South East Pacific were more dissimilar sharing only a few species. The present study provides new Tonga Trench records of the vertical ranges of A. gigantea, E. gryllus, and H. dubia. It also extends the maximum known depth of H. dubia to 10,807 m. This thesis expanded our current knowledge of A. gigantea, by reporting the first instance of this large amphipod in the Tonga Trench, and the second known instance of the species at hadal depths. An analysis of Hirondellea dubia population structure revealed ontogenetic vertical structuring in the Tonga Trench. Juveniles dominated the composition in the shallow end of the H. dubia vertical range, while very few juveniles were found at the deepest site. Juveniles were substantially smaller at ˜6,250 m compared to ˜10,800 m, and this may suggest that juveniles migrate down the trench slope with increasing age. The most likely mechanism for distributing juveniles to the shallower depths is the ascending migration of brooding females. However, this is still not certain as no brooding females were captured. The shallower depth provides a higher quality of food source and the reduced hydrostatic pressure allows for a faster metabolic rate. Thus, this distribution is likely driven by the distribution of food sources throughout the trench in combination with hydrostatic pressure. The dimensions of several established proxies for total length were evaluated for H. dubia. Pereonite 2-7 had the strongest correlation to total length, however it was highly distorted by dorsal curvature. Both the pereonite 2-7 and the pleosome were considered inaccurate due to sexual dimorphism making them inappropriate as proxies. Pereonite 1 was proportionately larger in juvenile lifestages. However, overall pereonite 1 was considered the strongest candidate for a proxy, this is because it was the least influenced by dorsal curvature and was a conspicuous segment that was easy to measure.</p>

Scavenging amphipods of the Tonga Trench: an analysis of community assemblage and population structure

<p>The hadal zone is the common name for the deepest section of the ocean (6,000-11,000 m depth). It encompasses 45 % of the ocean’s depth range, and is mostly represented by oceanic trenches. Trench habitats lack sufficient sampling and the communities within are not well understood. Often, samples are derived from a single depth and thus the population dynamics of trench communities have not been analysed comprehensively. Scavenging amphipods are abundant and diverse taxa in the trench environment, and have been found in every trench sampled to date. They rapidly intercept and consume carrion falls at the deepest trench depths, and act as key prey items to predators in the shallower depths of the hadal zone. There appears to be a relationship of increasing abundance and decreasing diversity of scavenging amphipods with depth. However in the Tonga Trench, sampling of hadal amphipods has been limited, and these patterns remain unclear. The QUELLE (Quest for the Limit of Life) project in 2013 was led by The Japan Agency for Marine-Earth Science and Technology (JAMSTEC). As part of this project, the YOK 13-10 voyage examined scavenging amphipods in the Tonga Trench. The voyage used baited traps to sample depths of ˜6,250 m and ˜10,800 m from October 6 – October 21 in 2013. The main objectives of the present study were to: identify scavenging amphipod assemblages within the Tonga Trench and compare them to other trenches of the South Pacific; analyse the population structure of Hirondellea dubia between depths in the Tonga Trench; and identify a suitable total length proxy for H. dubia. Six species of amphipods were identified from depths of ˜6,250 m and ˜10,800 m in the Tonga Trench. At ˜6,250 m Alicella gigantea, Eurythenes gryllus, H. dubia, Bathycallisoma schellenbergi, an alicellid species, and a gammarid species were recovered. In contrast, H. dubia was the only species recovered from ˜10,800 m. The abundance of amphipods was higher at the ˜10,800 m site while the diversity was much lower. The assemblage of scavenging amphipods in the Tonga Trench was similar to those from past sampling efforts in the same trench. There were also similarities to the assemblages in the adjacent Kermadec Trench, and together these observations support the classification of these two trenches as a single biogeographic province. The assemblages in the Peru-Chile Trench in the South East Pacific were more dissimilar sharing only a few species. The present study provides new Tonga Trench records of the vertical ranges of A. gigantea, E. gryllus, and H. dubia. It also extends the maximum known depth of H. dubia to 10,807 m. This thesis expanded our current knowledge of A. gigantea, by reporting the first instance of this large amphipod in the Tonga Trench, and the second known instance of the species at hadal depths. An analysis of Hirondellea dubia population structure revealed ontogenetic vertical structuring in the Tonga Trench. Juveniles dominated the composition in the shallow end of the H. dubia vertical range, while very few juveniles were found at the deepest site. Juveniles were substantially smaller at ˜6,250 m compared to ˜10,800 m, and this may suggest that juveniles migrate down the trench slope with increasing age. The most likely mechanism for distributing juveniles to the shallower depths is the ascending migration of brooding females. However, this is still not certain as no brooding females were captured. The shallower depth provides a higher quality of food source and the reduced hydrostatic pressure allows for a faster metabolic rate. Thus, this distribution is likely driven by the distribution of food sources throughout the trench in combination with hydrostatic pressure. The dimensions of several established proxies for total length were evaluated for H. dubia. Pereonite 2-7 had the strongest correlation to total length, however it was highly distorted by dorsal curvature. Both the pereonite 2-7 and the pleosome were considered inaccurate due to sexual dimorphism making them inappropriate as proxies. Pereonite 1 was proportionately larger in juvenile lifestages. However, overall pereonite 1 was considered the strongest candidate for a proxy, this is because it was the least influenced by dorsal curvature and was a conspicuous segment that was easy to measure.</p>

The ESA MIPAS/ENVISAT Level2-v8 dataset: 10 years of measurements retrieved with ORM v8.22

The observations acquired during the full mission of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument, on board the European Space Agency ENVISAT satellite, have been analysed with version 8.22 of the Optimised Retrieval Model (ORM), originally developed as the scientific prototype of the ESA level 2 processor for MIPAS observations. The results of the analyses have been included into the MIPAS level 2 version 8 (level2-v8) database containing atmospheric fields of pressure, temperature and volume mixing ratio of MIPAS main targets H2O, O3, HNO3, CH4, N2O, and NO2, along with the minor gases CFC-11, ClONO2, N2O5, CFC-12, COF2, CCl4, CF4, HCFC-22, C2H2, CH3Cl, COCl2, C2H6, OCS, HDO. The database covers all the measurements acquired by MIPAS in the nominal measurement mode of the Full Resolution (FR) part of the mission (from July 2002 to March 2004) and all the observation modes of the Optimised Resolution (OR) part (from January 2005 to April 2012). The number of species included in the MIPAS level2-v8 data-set makes it of particular importance for the studies of stratospheric chemistry. The database is considered by ESA the final release of the MIPAS level 2 products. The ORM algorithm is operated at the vertical grid coincident to the tangent altitudes of the observations or to a subset of them, spanning (in the nominal mode) the altitude range from 6 to 68 km in the FR phase and from 6 to 70 km in the OR period. In the latitude domain, FR profiles are spaced by about 4.7 degrees while the OR profiles are spaced by about 3.7 degrees. For each retrieved species the auxiliary data and the retrieval choices are described. Each product is characterised in terms of the retrieval error, spatial resolution, and 'useful' vertical range in both phases of the MIPAS mission. These depend on the characteristics of the measurements (spectral and vertical resolution of the measurements), on the retrieval choices (number of spectral points included in the analyses, number of altitudes included in the vertical retrieval grid), and on the information content of the measurements for each trace species. For temperature, water vapour, ozone and nitric acid the number of degrees of freedom is significantly larger in the OR phase than in the FR one, mainly due to the finer vertical measurement grid. In the FR phase some trace species are characterised by a smaller retrieval error with respect to the OR phase, mainly due to the larger number of spectral points used in the analyses, along with the reduced vertical resolution. The way of handling possible caveats (negative VMR, vertical grid representation) is discussed. The quality of the retrieved profiles is assessed through four criteria, two providing information on the successful convergence of the retrieval iterations, one on the capability of the retrieval to reproduce the measurements, and one on the presence of outliers. An easy way to identify and filter the problematic profiles with the information contained in the output files is provided. MIPAS level2-v8 data are available to the scientific community through the ESA portal https://earth.esa.int/eogateway/.

A Late Pleistocene Wetland Setting in the Arid Jurf ed Darawish Region in Central Jordan

Current conditions in the southern Levant are hyperarid, and local communities rely on fossil subsurface water resources. The timing of more favourable wetter periods and also their spatial characteristics are not yet well constrained. To improve our understanding of past climate and environmental conditions in the deserts of the southern Levant, sedimentary sections including artefact-bearing beds from Jurf ed Darawish on the Central Jordanian Plateau were investigated using sedimentological and micropalaeontological analyses and OSL dating. Grain-size analysis and structures of the clayey-silty sediments show that they mainly represent reworked loess deposits. The OSL ages suggest that these fine-grained sediments were accumulated during Marine Isotope Stages (MIS) 5-3. Recorded ostracod valves (mostly Potamocypris, Ilyocypris and Pseudocandona), remains of aquatic and terrestrial gastropod shells, and charophyte gyrogonites and stem encrustations indicate that an in-stream wetland existed at the location of Jurf ed Darawish during MIS 5-4 which was replaced by a vegetated alluvial plain in MIS 3. The prevailing aggradational setting was replaced by an erosional setting sometime after 30 ka. Abundant artefacts, distributed over a vertical range of up to 40 cm in a bed covered by a sedimentary sequence of 12-m thickness, provide evidence for the presence of humans in the region during a relatively long period from ca. 85 to 65 ka. The reconstruction of an in-stream wetland at Jurf ed Darawish, and the presence of humans at the site and in other desert regions of the Jordanian Plateau, the Wadi Arava/Araba, and the Negev and the Nefud deserts, show that the regional climate in the late MIS 5 and MIS 4 was significantly wetter than today and provided favourable conditions for humans in the Southern Levant and the northwestern Arabian Peninsula.

An Entropy-Weighting Method for Efficient Power-Line Feature Evaluation and Extraction from LiDAR Point Clouds

Power-line inspection is an important means to maintain the safety of power networks. Light detection and ranging (LiDAR) technology can provide high-precision 3D information about power corridors for automated power-line inspection, so there are more and more utility companies relying on LiDAR systems instead of traditional manual operation. However, it is still a challenge to automatically detect power lines with high precision. To achieve efficient and accurate power-line extraction, this paper proposes an algorithm using entropy-weighting feature evaluation (EWFE), which is different from the existing hierarchical-multiple-rule evaluation of many geometric features. Six significant features are selected (Height above Ground Surface (HGS), Vertical Range Ratio (VRR), Horizontal Angle (HA), Surface Variation (SV), Linearity (LI) and Curvature Change (CC)), and then the features are combined to construct a vector for quantitative evaluation. The feature weights are determined by an entropy-weighting method (EWM) to achieve optimal distribution. The point clouds are filtered out by the HGS feature, which possesses the highest entropy value, and a portion of non-power-line points can be removed without loss of power-line points. The power lines are extracted by evaluation of the other five features. To decrease the interference from pylon points, this paper analyzes performance in different pylon situations and performs an adaptive weight transformation. We evaluate the EWFE method using four datasets with different transmission voltage scales captured by a light unmanned aerial vehicle (UAV) LiDAR system and a mobile LiDAR system. Experimental results show that our method demonstrates efficient performance, while algorithm parameters remain consistent for the four datasets. The precision F value ranges from 98.4% to 99.7%, and the efficiency ranges from 0.9 million points/s to 5.2 million points/s.