scholarly journals A quantitative comparison of towed-camera and diver-camera transects for monitoring coral reefs

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11090
Author(s):  
Anna K. Cresswell ◽  
Nicole M. Ryan ◽  
Andrew J. Heyward ◽  
Adam N. H. Smith ◽  
Jamie Colquhoun ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Shallow Water ◽  
Repeated Measures ◽  
Low Cost ◽  
Autonomous Underwater Vehicles ◽  
Structural Complexity ◽  
Percent Cover ◽  
Benthic Assemblages ◽  
Focal Distance ◽  
Water Coral

Novel tools and methods for monitoring marine environments can improve efficiency but must not compromise long-term data records. Quantitative comparisons between new and existing methods are therefore required to assess their compatibility for monitoring. Monitoring of shallow water coral reefs is typically conducted using diver-based collection of benthic images along transects. Diverless systems for obtaining underwater images (e.g. towed-cameras, remotely operated vehicles, autonomous underwater vehicles) are increasingly used for mapping coral reefs. Of these imaging platforms, towed-cameras offer a practical, low cost and efficient method for surveys but their utility for repeated measures in monitoring studies has not been tested. We quantitatively compare a towed-camera approach to repeated surveys of shallow water coral reef benthic assemblages on fixed transects, relative to benchmark data from diver photo-transects. Differences in the percent cover detected by the two methods was partly explained by differences in the morphology of benthic groups. The reef habitat and physical descriptors of the site—slope, depth and structural complexity—also influenced the comparability of data, with differences between the tow-camera and the diver data increasing with structural complexity and slope. Differences between the methods decreased when a greater number of images were collected per tow-camera transect. We attribute lower image quality (variable perspective, exposure and focal distance) and lower spatial accuracy and precision of the towed-camera transects as the key reasons for differences in the data from the two methods and suggest changes to the sampling design to improve the application of tow-cameras to monitoring.

scholarly journals A Characterization of the Shallow-Water Coral Reefs and Associated Habitats of Puerto Rico

2004 ◽  
Vol 16 ◽  
Author(s):  
Matthew S. Kendall ◽  
Curtis R. Kruer ◽  
Ken R. Buja ◽  
John D. Christensen ◽  
Ernesto Diaz ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Coral Reefs ◽  
Shallow Water ◽  
Water Coral

scholarly journals Zooxanthellate, Sclerite-Free, and Pseudopinnuled Octocoral Hadaka nudidomus gen. nov. et sp. nov. (Anthozoa, Octocorallia) from Mesophotic Reefs of the Southern Ryukyus Islands

Diversity ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 176
Author(s):  
Yee Lau ◽  
James Reimer
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Shallow Water ◽  
Genetic Relationships ◽  
Marine Ecosystems ◽  
Marine Biota ◽  
Clade C ◽  
Coral Reef Ecosystems ◽  
Symbiodinium Clade ◽  
Water Coral

Shallow water coral reefs are the most diverse marine ecosystems, but there is an immense gap in knowledge when it comes to understanding the diversity of the vast majority of marine biota in these ecosystems. This is especially true when it comes to understudied small and cryptic coral reef taxa in understudied ecosystems, such as mesophotic coral reef ecosystems (MCEs). MCEs were reported in Japan almost fifty years ago, although only in recent years has there been an increase in research concerning the diversity of these reefs. In this study we describe the first stoloniferous octocoral from MCEs, Hadaka nudidomus gen. nov. et sp. nov., from Iriomote and Okinawa Islands in the southern Ryukyus Islands. The species is zooxanthellate; both specimens host Cladocopium LaJeunesse & H.J.Jeong, 2018 (formerly Symbiodinium ‘Clade C’) and were collected from depths of ~33 to 40 m. Additionally, H. nudidomus gen. nov. et sp. nov. is both sclerite-free and lacks free pinnules, and both of these characteristics are typically diagnostic for octocorals. The discovery and morphology of H. nudidomus gen. nov. et sp. nov. indicate that we still know very little about stoloniferous octocoral diversity in MCEs, their genetic relationships with shallower reef species, and octocoral–symbiont associations. Continued research on these subjects will improve our understanding of octocoral diversity in both shallow and deeper reefs.

Cirolanidae (Isopoda) From French Polynesian Coral Reefs: Description of Three New Species

Crustaceana ◽  
1993 ◽  
Vol 64 (2) ◽  
pp. 197-220 ◽  
Author(s):  
H.-G. Muller ◽  
B. Salvat
Keyword(s):  
New Species ◽  
Coral Reef ◽  
Coral Reefs ◽  
Shallow Water ◽  
Habitat Preference ◽  
French Polynesia ◽  
Three New Species ◽  
Water Coral

AbstractThis first contribution on cirolanid isopods from shallow water coral reef locations in French Polynesia (Bora Bora, Moorea) reports on three new species of the genera Cirolana and Metacirolana. They are described in detail, with remarks on their intergeneric affinities, habitat preference and biogeography.

scholarly journals Environmental controls on the global distribution of shallow-water coral reefs

2012 ◽  
Vol 39 (8) ◽  
pp. 1508-1523 ◽  
Author(s):  
Elena Couce ◽  
Andy Ridgwell ◽  
Erica J. Hendy
Keyword(s):  
Coral Reefs ◽  
Shallow Water ◽  
Global Distribution ◽  
Environmental Controls ◽  
Water Coral

scholarly journals Diversity and abundance of conspicuous macrocrustaceans on coral reefs differing in level of degradation

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4922 ◽  
Author(s):  
Roberto González-Gómez ◽  
Patricia Briones-Fourzán ◽  
Lorenzo Álvarez-Filip ◽  
Enrique Lozano-Álvarez
Keyword(s):  
Coral Reefs ◽  
Habitat Degradation ◽  
Coral Cover ◽  
Structural Complexity ◽  
Live Coral ◽  
Percent Cover ◽  
Acropora Palmata ◽  
Coral Rubble ◽  
Local Diversity ◽  
Census Techniques

Coral reefs sustain abundant and diverse macrocrustaceans that perform multiple ecological roles, but coral reefs are undergoing massive degradation that may be driving changes in the species composition and abundance of reef-associated macrocrustaceans. To provide insight into this issue, we used non-destructive visual census techniques to compare the diversity and abundance of conspicuous macrocrustaceans (i.e., those >1 cm and visible without disturbance) between two shallow Caribbean coral reefs similar in size (∼1.5 km in length) and close to each other, but one (“Limones”) characterized by extensive stands of the branching coral Acropora palmata, and the other (“Bonanza”) dominated by macroalgae and relic coral skeletons and rubble (i.e., degraded). We also assessed the structural complexity of each reef and the percent cover of various benthic community components. Given the type of growth of A. palmata, we expected to find a greater structural complexity, a higher cover of live coral, and a lower cover of macroalgae on Limones, and hence a more diverse and abundant macrocrustacean community on this reef compared with Bonanza. Overall, we identified 63 macrocrustacean species (61 Decapoda and two Stomatopoda). Contrary to our expectations, structural complexity did not differ significantly between the back-reef zones of these reefs but varied more broadly on Limones, and the diversity and abundance of macrocrustaceans were higher on Bonanza than on Limones despite live coral cover being higher on Limones and macroalgal cover higher on Bonanza. However, the use of various types of microhabitats by macrocrustaceans differed substantially between reefs. On both reefs, the dominant species were the clinging crab Mithraculus coryphe and the hermit crab Calcinus tibicen, but the former was more abundant on Bonanza and the latter on Limones. M. coryphe occupied a diverse array of microhabitats but mostly coral rubble and relic skeletons, whereas C. tibicen was often, but not always, found associated with colonies of Millepora spp. A small commensal crab of A. palmata, Domecia acanthophora, was far more abundant on Limones, emerging as the main discriminant species between reefs. Our results suggest that local diversity and abundance of reef-associated macrocrustaceans are partially modulated by habitat degradation, the diversity of microhabitat types, and the establishment of different commensal associations rather than by structural complexity alone.

scholarly journals Computational Complexity Reduction of Neural Networks of Brain Tumor Image Segmentation by Introducing Fermi–Dirac Correction Functions

Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 223
Author(s):  
Yen-Ling Tai ◽  
Shin-Jhe Huang ◽  
Chien-Chang Chen ◽  
Henry Horng-Shing Lu
Keyword(s):  
Neural Networks ◽  
Deep Learning ◽  
Computational Complexity ◽  
High Performance ◽  
Low Cost ◽  
Structural Complexity ◽  
Correction Function ◽  
Computational Time ◽  
Learning Methods ◽  
Band Theory

Nowadays, deep learning methods with high structural complexity and flexibility inevitably lean on the computational capability of the hardware. A platform with high-performance GPUs and large amounts of memory could support neural networks having large numbers of layers and kernels. However, naively pursuing high-cost hardware would probably drag the technical development of deep learning methods. In the article, we thus establish a new preprocessing method to reduce the computational complexity of the neural networks. Inspired by the band theory of solids in physics, we map the image space into a noninteraction physical system isomorphically and then treat image voxels as particle-like clusters. Then, we reconstruct the Fermi–Dirac distribution to be a correction function for the normalization of the voxel intensity and as a filter of insignificant cluster components. The filtered clusters at the circumstance can delineate the morphological heterogeneity of the image voxels. We used the BraTS 2019 datasets and the dimensional fusion U-net for the algorithmic validation, and the proposed Fermi–Dirac correction function exhibited comparable performance to other employed preprocessing methods. By comparing to the conventional z-score normalization function and the Gamma correction function, the proposed algorithm can save at least 38% of computational time cost under a low-cost hardware architecture. Even though the correction function of global histogram equalization has the lowest computational time among the employed correction functions, the proposed Fermi–Dirac correction function exhibits better capabilities of image augmentation and segmentation.

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