scholarly journals UTILIZING UNDERWATER THREE-DIMENSIONAL MODELING TO ENHANCE ECOLOGICAL AND BIOLOGICAL STUDIES OF CORAL REEFS

2015 ◽  
Vol XL-5/W5 ◽  
pp. 61-66 ◽  
Author(s):  
J. H. R. Burns ◽  
D. Delparte ◽  
R. D. Gates ◽  
M. Takabayashi
Keyword(s):  
Coral Reefs ◽  
Structural Characteristics ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Ecological Processes ◽  
3 Dimensional ◽  
Three Dimensional Modeling ◽  
Digital Elevation ◽  
Biological Studies ◽  
Coral Reef Ecosystems

The structural complexity of coral reefs profoundly affects the biodiversity, productivity, and overall functionality of reef ecosystems. Conventional survey techniques utilize 2-dimensional metrics that are inadequate for accurately capturing and quantifying the intricate structural complexity of scleractinian corals. A 3-dimensional (3D) approach improves the capacity to accurately measure architectural complexity, topography, rugosity, volume, and other structural characteristics that play a significant role in habitat facilitation and ecosystem processes. This study utilized Structure-from-Motion (SfM) photogrammetry techniques to create 3D mesh models for several Hawaiian corals that represent distinct morphological phenotypes. The orthophotos and digital elevation models generated from the SfM process were imported into geospatial analysis software in order to quantify several metrics pertaining to 3D complexity that are known to affect ecosystem biodiversity and productivity. The 3D structural properties of the reconstructed coral colonies were statistically analyzed to determine if the each species represents a unique morpho-functional group. The SfM reconstruction techniques described in this paper can be utilized for an array of research purposes to improve our understanding of how changes in coral composition affect habitat structure and ecological processes in coral reef ecosystems.

scholarly journals COMPARISON OF COMMERCIAL STRUCTURE-FROM-MOTION PHOTOGRAMMETY SOFTWARE USED FOR UNDERWATER THREE-DIMENSIONAL MODELING OF CORAL REEF ENVIRONMENTS

2017 ◽  
Vol XLII-2/W3 ◽  
pp. 127-131 ◽  
Author(s):  
J. H. R. Burns ◽  
D. Delparte
Keyword(s):  
Coral Reef ◽  
Structural Characteristics ◽  
Spatial Scales ◽  
3D Structure ◽  
Light Availability ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Physical Structure ◽  
Natural Environments ◽  
Ecological Processes

Structural complexity in ecosystems creates an assortment of microhabitat types and has been shown to support greater diversity and abundance of associated organisms. The 3D structure of an environment also directly affects important ecological parameters such as habitat provisioning and light availability and can therefore strongly influence ecosystem function. Coral reefs are architecturally complex 3D habitats, whose structure is intrinsically linked to the ecosystem biodiversity, productivity, and function. The field of coral ecology has, however, been primarily limited to using 2-dimensional (2D) planar survey techniques for studying the physical structure of reefs. This conventional approach fails to capture or quantify the intricate structural complexity of corals that influences habitat facilitation and biodiversity. A 3-dimensional (3D) approach can obtain accurate measurements of architectural complexity, topography, rugosity, volume, and other structural characteristics that affect biodiversity and abundance of reef organisms. Structurefrom- Motion (SfM) photogrammetry is an emerging computer vision technology that provides a simple and cost-effective method for 3D reconstruction of natural environments. SfM has been used in several studies to investigate the relationship between habitat complexity and ecological processes in coral reef ecosystems. This study compared two commercial SfM software packages, Agisoft Photoscan Pro and Pix4Dmapper Pro 3.1, in order to assess the cpaability and spatial accuracy of these programs for conducting 3D modeling of coral reef habitats at three spatial scales.

Benthic community composition influences within-habitat variation in macroalgal browsing on the Great Barrier Reef

2010 ◽  
Vol 61 (9) ◽  
pp. 999 ◽  
Author(s):  
C. Cvitanovic ◽  
A. S. Hoey
Keyword(s):  
Coral Reefs ◽  
Great Barrier Reef ◽  
Benthic Community ◽  
Spatial Scales ◽  
Structural Complexity ◽  
Barrier Reef ◽  
Removal Rates ◽  
Ecological Processes ◽  
Habitat Variation ◽  
Benthic Composition

The removal of macroalgae by herbivores is fundamental to the long-term persistence of coral reefs. Variation in macroalgal browsing has been documented across a range of spatial scales on coral reefs; however, few studies have examined the factors that influence within-habitat rates of herbivory. The aim of the present study was to quantify herbivory on two species of Sargassum across three bays on an inshore island in the central Great Barrier Reef (GBR), and to determine whether these removal rates were related to the benthic composition or herbivorous fish communities. Removal rates of Sargassum differed significantly among bays, with removal rates in the southern bay (66.9–83.0% per 3 h) being approximately double that of the two other bays (29.2–38.5% per 3 h). The removal rates displayed a direct relationship with the benthic community structure, in particular the cover of macroalgae and live plate corals. Although it is difficult to determine whether these relationships are related to the availability of food resources or the structural complexity of the substratum, they highlight the potential influence of benthic composition on ecological processes. Quantifying and understanding the drivers of herbivory across a range of spatial scales is essential to the future management of coral reefs.

scholarly journals Associations between Benthic Cover and Habitat Complexity Metrics Obtained from 3D Reconstruction of Coral Reefs at Different Resolutions

2020 ◽  
Vol 12 (6) ◽  
pp. 1011 ◽  
Author(s):  
Atsuko Fukunaga ◽  
John H. R. Burns ◽  
Kailey H. Pascoe ◽  
Randall K. Kosaki
Keyword(s):  
Fractal Dimension ◽  
Coral Reefs ◽  
Habitat Structure ◽  
Coral Cover ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Coralline Algae ◽  
Crustose Coralline Algae ◽  
Surface Areas ◽  
Abundance And Diversity

Quantifying the three-dimensional (3D) habitat structure of coral reefs is an important aspect of coral reef monitoring, as habitat architecture affects the abundance and diversity of reef organisms. Here, we used photogrammetric techniques to generate 3D reconstructions of coral reefs and examined relationships between benthic cover and various habitat metrics obtained at six different resolutions of raster cells, ranging from 1 to 32 cm. For metrics of 3D structural complexity, fractal dimension, which utilizes information on 3D surface areas obtained at different resolutions, and vector ruggedness measure (VRM) obtained at 1-, 2- or 4-cm resolution correlated well with benthic cover, with a relatively large amount of variability in these metrics being explained by the proportions of corals and crustose coralline algae. Curvature measures were, on the other hand, correlated with branching and mounding coral cover when obtained at 1-cm resolution, but the amount of variability explained by benthic cover was generally very low when obtained at all other resolutions. These results show that either fractal dimension or VRM obtained at 1-, 2- or 4-cm resolution, along with curvature obtained at 1-cm resolution, can effectively capture the 3D habitat structure provided by specific benthic organisms.

Modal Analysis of the Gantry Milling and Boring Machine Tool Beam Based on FEM

2012 ◽  
Vol 151 ◽  
pp. 424-428
Author(s):  
Zhong Liang Cao ◽  
Yan Ding ◽  
Qing Ming Hu ◽  
Qiang Guo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Modal Analysis ◽  
Structural Characteristics ◽  
Three Dimensional ◽  
Relative Deformation ◽  
Milling Machine ◽  
Element Analysis ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling

Fixed beam gantry for large CNC boring and milling machine to bear the beams on the rail side apron, and other parts ram weight under weight and size of deformation produced a result of the assembly accuracy of less than standard, use three-dimensional modeling software UG and finite element analysis software ANSYS for dynamic beam gantry milling machine CNC beam three-dimensional modeling and modal analysis, based on weight and apron beams, the weight of ram and other components in relative deformation amplitude, and the gantry milling machine processing characteristics and overall design of the structural characteristics of machine tools, assembly of the beam is proposed to note some issues and some ways to solve the assembly size requirements, through finite element analysis of the deformation and comparing the actual measured value, the experiment proved data on-site assembly solution with a good theoretical support.

scholarly journals Tutupan makroalga pada terumbu karang di kawasan konservasi perairan (KKP) Nusa Penida, Bali

DEPIK ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 69-75
Author(s):  
Muhammad Akhyar Maududi ◽  
Oktiyas Muzaky Luthfi
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Regional Planning ◽  
Water Mass ◽  
Initial Study ◽  
Food Sources ◽  
Marine Resources ◽  
Ecological Processes ◽  
Algae Growth ◽  
Coral Reef Ecosystems

The interaction between algae and coral is one of the most important of ecological processes in coral reef ecosystems. They are one of the main food sources in a large number of herbivorous animals in coral reef ecosystems. Makroalgae is also a major competitor in degrading coral reefs at a time when macroalgae gains dominate the coral reefs. Algae growth is relatively very fast, so it can be used as an indicator in the initial study to determine the processes that affect populations and coral reef communities. The purpose of this study is to determine the distribution of macroalgae cover on coral reefs in the Nusa Penida, Bali using the transect quadrant (1x1m2)x 100m method. This study shows that the lowest macroalgae cover at Crystal Bay and the highest in Buyuk can be concluded that the high macroalgae cover is made possible by the large supply of nutrients from the land which becomes the supplier of organic materials that increases the fertility of waters, meanwhile in the waters close to the high seas obtain additional nutrients derived from the lifting of the water mass (upwelling). Data and information are needed for the interest of regional planning towards the future related to the management and utilization of marine resources potential in the coastal area in Nusa Penida, Bali.Interaksi antara alga dan karang merupakan hal terpenting dari proses ekologi pada ekosistem terumbu karang. Mereka merupakan salah satu sumber produsen primer pada sejumlah besar hewan herbivora pada ekosistem terumbu karang. Makroalga juga menjadi pesaing utama dalam mendegradasi terumbu karang pada saat kelimpahaan makroalga mendominasi terhadap terumbu karang. Pertumbuhan alga tergolong sangat cepat, sehingga dapat digunakan sebagai indikator dalam studi awal untuk mengetahui proses yang mempengaruhi populasi dan komunitas terumbu karang. Tujuan dari penelitian ini adalah mengetahui sebaran tutupan makroalga pada terumbu karang di daerah utama wisata penyelaman Nusa Penida, Bali dengan menggunakan metode transek kuadran dengan ukuran (1x1m2) x 100 m. Penelitian ini menunjukan bahwa tutupan makroalga terendah pada Crystal Bay dan tertinggi di Buyuk dapat ditarik kesimpulan jika tingginya tutupan makroalga dimungkinkan oleh besarnya suplai nutrien daratan yang menjadi pensuplai bahan organik yang meningkatkan kesuburan perairan. Sedangkan pada  perairan yang dekat dengan laut lepas mendapat tambahan nutrien yang berasal dari pengangkatan massa air (upwelling). Data dan informasi ini diperlukan untuk kepentingan perencanaan pengembangan wilayah ke depannya yang terkait dengan pengelolaan dan pemanfaatan potensi sumberdaya laut di wilayah pesisir di Nusa Penida, Bali.

The Kinematics Modeling and Simulation of a Mechanical Arm in Nuclear Industry with Postpositional Drive

2014 ◽  
Vol 496-500 ◽  
pp. 754-759
Author(s):  
Rui Feng Zhao ◽  
Zhen Zhang ◽  
Jiu Qiang Cui
Keyword(s):  
Structural Characteristics ◽  
Three Dimensional ◽  
Inverse Kinematic ◽  
Nuclear Industry ◽  
Kinematic Constraints ◽  
Kinematics Model ◽  
Three Dimensional Modeling ◽  
Data Processing Software ◽  
Dimensional Modeling ◽  
Kinematics Modeling

For the particularity of the environment in nuclear industry, this paper puts forward a modularized mechanical arm with postpositional drive. On the basis of structural characteristics and kinematic constraints, the kinematics of robotic arm is analyzed. The D-H method is used for describing the workspace, based on considering the kinematic constraints, the forward kinematics model is achieved. Using an improved search method, the inverse kinematics solution is obtained. Through the simulation on data processing software, the validity of positive kinematics model and inverse kinematic solutions are verified. Finally, the trajectory planning is completed on the three-dimensional modeling platform.

Modeling and Simulation of Gait Analysis of Hexapod Robot

2013 ◽  
Vol 457-458 ◽  
pp. 639-642 ◽  
Author(s):  
Bing Bing Yan ◽  
Yang Li ◽  
Wen Bo Ren ◽  
Bao Lin Yin
Keyword(s):  
Simulation Model ◽  
Structural Characteristics ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Dynamic Contact ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Global Dynamics ◽  
Hexapod Robot ◽  
Three Dimensional Modeling

In order to solve the key issues such as the improvement of the movement smoothness of the center of mass and the movement coordination of each joint of the legs in the process the movement of the bionic hexapod robot, etc., establish bionic hexapod robot simulation model jointly by observing the movement characteristics and structural characteristics of the hexapod beetle and using three-dimensional modeling software SOLIDWORKS and mechanical system dynamics simulation software ADAMS and build the legs dynamic contact and collision model with the ground through the applied force constraint of ADAMS. Ultimately, form the global dynamics simulation model of the robot. Using the model the triangle gait of bionic hexapod robot is analyze, especially the straight and turning gait, which proves that the movement of robot is stable. The results lay the foundation for the further study and optimization of the bionic hexapod robot.

scholarly journals The role of geomorphic zonation in long-term changes in coral-community structure on a Caribbean fringing reef

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10103
Author(s):  
Alexis Enrique Medina-Valmaseda ◽  
Rosa E. Rodríguez-Martínez ◽  
Lorenzo Alvarez-Filip ◽  
Eric Jordan-Dahlgren ◽  
Paul Blanchon
Keyword(s):  
Coral Reefs ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Coastal Protection ◽  
Benthic Habitat ◽  
Ecological Indices ◽  
Ecological Processes ◽  
Spatial And Temporal Scales ◽  
The Impact

Ecological processes on coral reefs commonly have limited spatial and temporal scales and may not be recorded in their long-term geological history. The widespread degradation of Caribbean coral reefs over the last 40 years therefore provides an opportunity to assess the impact of more significant ecological changes on the geological and geomorphic structure of reefs. Here, we document the changing ecology of communities in a coral reef seascape within the context of its geomorphic zonation. By comparing basic ecological indices between historical and modern data we show that in 35 years the reef-front zone was transformed from a complex coral assemblage with a three-dimensional structure, to a size-homogenized and flattened one that is quasi indistinguishable from the adjacent non-accretional coral-ground zone. Today coral assemblages at Punta Maroma are characterized by the dominance of opportunistic species which are either tolerant to adverse environmental conditions, including sedimentation, or are known to be the first scleractinian species to recruit on disturbed reefs, implying they reflect a post-hurricane stage of adjustment. Despite an increase in similarity in ecological indices, the reef-front and coral-ground geomorphic zones still retain significant differences in coral assemblages and benthic habitat and are not homogeneous. The partial convergence of coral assemblages certainly has important consequences for the ecology and geological viability of the reef and its role in coastal protection, but environmental physical drivers continue to exert a fundamental role in the character and zonation of benthic communities of this reef seascape.

scholarly journals Needs and Gaps in Optical Underwater Technologies and Methods for the Investigation of Marine Animal Forest 3D-Structural Complexity

2021 ◽  
Vol 8 ◽  
Author(s):  
Paolo Rossi ◽  
Massimo Ponti ◽  
Sara Righi ◽  
Cristina Castagnetti ◽  
Roberto Simonini ◽  
...  
Keyword(s):  
Benthic Communities ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Marine Animal ◽  
Growth Data ◽  
Ecological Processes ◽  
Spatial And Temporal Scales ◽  
Technological Advances ◽  
Data Collection And Analysis ◽  
Data Acquisition And Processing

Marine animal forests are benthic communities dominated by sessile suspension feeders (such as sponges, corals, and bivalves) able to generate three-dimensional (3D) frameworks with high structural complexity. The biodiversity and functioning of marine animal forests are strictly related to their 3D complexity. The present paper aims at providing new perspectives in underwater optical surveys. Starting from the current gaps in data collection and analysis that critically limit the study and conservation of marine animal forests, we discuss the main technological and methodological needs for the investigation of their 3D structural complexity at different spatial and temporal scales. Despite recent technological advances, it seems that several issues in data acquisition and processing need to be solved, to properly map the different benthic habitats in which marine animal forests are present, their health status and to measure structural complexity. Proper precision and accuracy should be chosen and assured in relation to the biological and ecological processes investigated. Besides, standardized methods and protocols are strictly necessary to meet the FAIR (findability, accessibility, interoperability, and reusability) data principles for the stewardship of habitat mapping and biodiversity, biomass, and growth data.

scholarly journals Characterizing Geomorphology of Mesophotic Coral Reef Ecosystems in the Southwestern Gulf of Mexico: Implications for Conservation and Management

2021 ◽  
Vol 8 ◽  
Author(s):  
Melissa Mayorga-Martínez ◽  
Javier Bello-Pineda ◽  
Héctor Perales-Valdivia ◽  
Horacio Pérez-España ◽  
William D. Heyman
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Gulf Of Mexico ◽  
Structural Complexity ◽  
Windward Side ◽  
Slope Aspect ◽  
Depth Range ◽  
Core Zone ◽  
Reef Complex ◽  
Coral Reef Ecosystems

Coral reefs are the most biodiverse ecosystems on earth and are presently experiencing severe declines globally. Shallow coral reef ecosystems (<30 m) have been studied extensively while mesophotic coral ecosystems (MCE) are poorly studied. As a result, MCE are rarely included in marine reserve design and management, despite their ecological importance and connectivity to shallow reefs. In this study, we assessed the fine-scale topographic complexity, a proxy for structural complexity, for a group of coastal coral reefs in a marine park in the southwestern Gulf of Mexico, in depths between 2 and 49 m. We conducted hydrographic surveys using a semi-portable multibeam echosounder system to produce 3D bathymetry digital terrain models (DTM) with a 2.5 m spatial resolution for three submerged bank reefs and two emerging reefs. From these models, descriptive terrain parameters were calculated for each reef, including slope, aspect, curvature, rugosity and ruggedness. Results show that all reefs are predominantly northeast-southwest oriented, with well-defined leeward and windward sides. For the three submerged bank reefs, structural complexity increased with depth. Estimated mean ruggedness and rugosity were highest at 20–40 m depth range on windward side slopes. Emerging reefs showed high structural complexity, particularly at the 25–40 m depth range. We identified a spur and groove zone with maximum ruggedness (0.26) and rugosity (3.17) values, and four channels with steep slopes (68°) and dispersed mounds. We found that at mesophotic depths (>30 m), southern reefs basements from two distinct reefs merge to form a continuous complex. This has important management implications since presently, only 28.7% of this reef complex (mostly shallow areas) are within the existing limits of the marine park’s core zone. Considering the newly recognized importance of MCE, we propose expanding and reshaping the core zone to include the entire reef complex which mostly encompasses MCE with high structural complexity. Our study illustrates the value of semi-portable MBES for marine planning in developing countries and remote poorly studied areas.

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