Small-scale spatial distribution of phosphorus fractions in soils from silicate parent material with different degree of podzolization

Marine conservation areas are an important tool for the sustainable management of multispecies, small-scale fisheries. Effective spatial management requires a proper understanding of the spatial distribution of target species and the identification of its environmental drivers. Small-scale fisheries, however, often face scarcity and low-quality of data. In these situations, approaches for the prioritization of conservation areas need to deal with scattered, biased, and short-term information and ideally should quantify data- and model-specific uncertainties for a better understanding of the risks related to management interventions. We used a Bayesian hierarchical species distribution modeling approach on annual landing data of the heavily exploited, small-scale, and data-poor fishery of Chwaka Bay (Zanzibar) in the Western Indian Ocean to understand the distribution of the key target species and identify potential areas for conservation. Few commonalities were found in the set of important habitat and environmental drivers among species, but temperature, depth, and seagrass cover affected the spatial distribution of three of the six analyzed species. A comparison of our results with information from ecological studies suggests that our approach predicts the distribution of the analyzed species reasonably well. Furthermore, the two main common areas of high relative abundance identified in our study have been previously suggested by the local fisher as important areas for spatial conservation. By using short-term, catch per unit of effort data in a Bayesian hierarchical framework, we quantify the associated uncertainties while accounting for spatial dependencies. More importantly, the use of accessible and interpretable tools, such as the here created spatial maps, can frame a better understanding of spatio-temporal management for local fishers. Our approach, thus, supports the operability of spatial management in small-scale fisheries suffering from a general lack of long-term fisheries information and fisheries independent data.

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Spatial distribution of Antarctic shrimps (Crustacea: Decapoda) by underwater photography

Antarctic Science ◽

10.1017/s0954102091000469 ◽

1991 ◽

Vol 3 (4) ◽

pp. 363-369 ◽

Cited By ~ 23

Author(s):

Julian Gutt ◽

M. Gorny ◽

W. Arntz

Keyword(s):

Spatial Distribution ◽

Continental Shelf ◽

Weddell Sea ◽

Small Scale ◽

Frequency Distributions ◽

South Eastern ◽

Direct Observations ◽

Underwater Photography ◽

Dispersion Patterns ◽

Eastern Weddell Sea

Three species of shrimps (Notocrangon antarcticus, Chorismus antarcticus, Nematocarcinus lanceopes) were investigated in the south-eastern Weddell Sea using of underwater photography. Maximum densities of c. 100 specimens per 100 m2 were found for N. antarcticus on the continental shelf (200–600 m) and for N. lanceopes on the slope (800–1200 m). Small-scale dispersion patterns and size-frequency distributions were analyzed within dense concentrations. These direct observations indicate that the behaviour of the three species is adapted to different habitats with Chorismus distribution correlated with that of sponges and Notocrangon with base sediment.

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High-Temperture Structural Analysis on a Small-Scale PHE Prototype Considering Mechanical Properties in the Heat-Affected Zone and in the Weld Zone

Volume 2: Plant Systems, Structures, and Components; Safety and Security; Next Generation Systems; Heat Exchangers and Cooling Systems ◽

10.1115/icone20-power2012-54184 ◽

2012 ◽

Author(s):

Kee-Nam Song ◽

Sung-Deok Hong ◽

Hong-Yoon Park

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Structural Analysis ◽

Performance Test ◽

Weld Zone ◽

Parent Material ◽

Small Scale ◽

Hastelloy X ◽

Production Of Hydrogen ◽

Gas Loop

PHE (Process Heat Exchanger) is a key component in transferring the high temperature heat generated from a VHTR (Very High Temperature Reactor) to the chemical reaction for massive production of hydrogen. A performance test on a small-scale PHE prototype made of Hastelloy-X is currently undergoing in a small-scale gas loop at the Korea Atomic Energy Research Institute. Previous researches on the high-temperature structural analysis of the small-scale PHE prototype had been performed using parent material properties over the whole region. In this study, high-temperature elastic structural analysis considering mechanical properties in the weld zone was performed and the analysis result was compared with previous researches.

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Assessment of the heterogeneity of hydraulic properties in gravelly outwash plains: a regionally scaled sedimentological analysis in the Munich gravel plain, Germany

Hydrogeology Journal ◽

10.1007/s10040-020-02205-y ◽

2020 ◽

Vol 28 (8) ◽

pp. 2657-2674

Author(s):

Markus Theel ◽

Peter Huggenberger ◽

Kai Zosseder

Keyword(s):

Spatial Distribution ◽

Hydraulic Conductivity ◽

Large Scale ◽

Regional Scale ◽

Pumping Test ◽

Small Scale ◽

Significant Heterogeneity ◽

Conductivity Distribution ◽

Braided Rivers ◽

Sedimentary Deposits

AbstractThe favorable overall conditions for the utilization of groundwater in fluvioglacial aquifers are impacted by significant heterogeneity in the hydraulic conductivity, which is related to small-scale facies changes. Knowledge of the spatial distribution of hydraulically relevant hydrofacies types (HF-types), derived by sedimentological analysis, helps to determine the hydraulic conductivity distribution and thus contribute to understanding the hydraulic dynamics in fluvioglacial aquifers. In particular, the HF-type “open framework gravel (OW)”, which occurs with the HF-type “bimodal gravel (BM)” in BM/OW couplings, has an intrinsically high hydraulic conductivity and significantly impacts hydrogeological challenges such as planning excavation-pit drainage or the prognosis of plumes. The present study investigates the properties and spatial occurrence of HF-types in fluvioglacial deposits at regional scale to derive spatial distribution trends of HF-types, by analyzing 12 gravel pits in the Munich gravel plain (southern Germany) as analogues for outwash plains. The results are compared to the reevaluation of 542 pumping tests. Analysis of the HF-types and the pumping test data shows similar small-scale heterogeneities of the hydraulic conductivity, superimposing large-scale trends. High-permeability BM/OW couples and their dependence on recognizable discharge types in the sedimentary deposits explain sharp-bounded small-scale heterogeneities in the hydraulic conductivity distribution from 9.1 × 10−3 to 2.2 × 10−4 m/s. It is also shown that high values of hydraulic conductivity can be interpolated on shorter distance compared to lower values. While the results of the HF-analysis can be transferred to other fluvioglacial settings (e.g. braided rivers), regional trends must be examined with respect to the surrounding topography.

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Variations of the Coronal Radiation in X-ray Related to Coronal Holes, Active Region Loop Systems, Bright Points

International Astronomical Union Colloquium ◽

10.1017/s0252921100024660 ◽

1994 ◽

Vol 143 ◽

pp. 159-171

Author(s):

Ester Antonucci

Keyword(s):

Magnetic Field ◽

Spatial Distribution ◽

Large Scale ◽

Coronal Holes ◽

Active Regions ◽

Coronal Magnetic Field ◽

Small Scale ◽

X Ray ◽

Coronal Structures

The coronal features observed in X-ray emission, varying from the small-scale, short-lived bright points to the large-scale, long-lived coronal holes, are closely associated with the coronal magnetic field and its topology, and their variability depends strongly on the solar cycle. Here we discuss the spatial distribution of the coronal structures, the frequency distribution of the brightness variations in active regions, and the role of magnetic reconnection in determining the variability of the coronal features, on the basis of the new observations of the soft X-ray emission recently obtained with the Yohkoh satellite and the NIXT experiment.

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Small Scale Fluctuations in the Microwave Background Radiation Associated with the Formation of Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900016296 ◽

1977 ◽

Vol 74 ◽

pp. 327-334

Author(s):

R. A. Sunyaev

Keyword(s):

Spatial Distribution ◽

Background Radiation ◽

Gravitational Instability ◽

Thomson Scattering ◽

Small Scale ◽

Clusters Of Galaxies ◽

Microwave Background ◽

Microwave Background Radiation ◽

Expansion Of The Universe ◽

The Universe

According to current ideas, massive extragalactic systems such as galaxies and clusters of galaxies formed as a result of the growth of small fluctuations in density and velocity which were present in the early stages of expansion of the Universe under the influence of gravitational instability. According to the hot model of the Universe at the epoch corresponding to a redshift z ≈ 1500, recombination of primaeval hydrogen took place and as a result the optical depth of the Universe to Thomson scattering decreased abruptly from about 1000 to 1 - the Universe became transparent. Therefore the observed angular distribution of the microwave background radiation (MWBR) contains information about inhomogeneities in its spatial distribution at a redshift z ∼ 1000. Silk (1968) was the first to note that this “photograph” of the Universe at the epoch of recombination must be enscribed with fluctuations associated with perturbations in the space density and velocity of motion of matter which will later lead to the formation of galaxies and clusters of galaxies.

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Spatial Distribution and Environmental Significance of Phosphorus Fractions in River Sediments and Its Influencing Factor from Hongze and Tiaoxi Watersheds, Eastern China

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17165787 ◽

2020 ◽

Vol 17 (16) ◽

pp. 5787

Author(s):

Ja Bawk Marip ◽

Xuyin Yuan ◽

Hai Zhu ◽

Isaac Kwesi Nooni ◽

Solomon O. Y. Amankwah ◽

...

Keyword(s):

Spatial Distribution ◽

Environmental Influence ◽

Rank Order ◽

Influencing Factor ◽

Eastern China ◽

Land Use Changes ◽

River Sediments ◽

Extraction Procedure ◽

Phosphorus Fractions ◽

Ambient Conditions

This study explored the spatial distribution of phosphorus fractions in river sediments and analyzed the relationship between different phosphorus fractions and their environmental influence on the sediments within different watersheds in Eastern China. River sediments from two inflow watersheds (Hongze and Tiaoxi) to Hongze and Taihu Lake in Eastern China were analyzed by the sequential extraction procedure. Five fractions of sedimentary phosphorus, including freely sorbed phosphorus (NH4Cl-P), redox-sensitive phosphorus (BD-P), bound phosphorus metal oxide (NaOH-P), bound phosphorus calcium (HCl-P), and residual phosphorus (Res-P) were all analyzed. The orders of rankings for the P fractions of the rivers Anhe and Suihe were HCl-P > NaOH-P > BD-P > NH4Cl-P and HCl-P > BD-P > NaOH-P > NH4Cl-P, respectively. For the rank order of the Hongze watershed, HCl-P was higher while the NH4Cl-P contents were significantly lower. The rank order for the Dongtiaoxi River was NaOH-P > HCl-P > BD-P > NH4Cl-P, and that of Xitiaoxi River was NaOH-P > BD-P > HCl-P > NH4Cl-P. Compared with the phosphorus forms of the Tiaoxi watershed, NaOH-P contents were significantly higher compared to HCl-P, which was significantly higher in the Hongze watershed. In comparison, NH4Cl-P contents were significantly lower in both. Variations may be attributed to differential discharge of the P form in the watershed due to land-use changes and urban river ambient conditions.

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