scholarly journals Assessing Fine-Scale Distribution and Volume of Mediterranean Algal Reefs through Terrain Analysis of Multibeam Bathymetric Data. A Case Study in the Southern Adriatic Continental Shelf

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 157
Author(s):  
Fabio Marchese ◽  
Valentina Alice Bracchi ◽  
Giulia Lisi ◽  
Daniela Basso ◽  
Cesare Corselli ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Ad Hoc ◽  
Anthropogenic Impacts ◽  
Structural Complexity ◽  
Coralline Algae ◽  
Global Changes ◽  
Terrain Analysis ◽  
Crustose Coralline Algae ◽  
Bathymetric Data ◽  
The Mediterranean

In the Mediterranean Sea, crustose coralline algae form endemic algal reefs known as Coralligenous (C) build-ups. The high degree of complexity that C can reach through time creates notable environmental heterogeneity making C a major hotspot of biodiversity for the Mediterranean basin. C build-up can variably modify the submarine environment by affecting the evolution of submerged landforms, although its role is still far from being systematically defined. Our work proposes a new, ad-hoc semi-automated, GIS-based methodology to map the distribution of C build-ups in shallow coastal waters using high-resolution bathymetric data, collected on a sector of the southern Apulian continental shelf (Southern Adriatic Sea, Italy). Our results quantitatively define the 3D distribution of C in terms of area and volume, estimating more than 103,000 build-ups, covering an area of roughly 305,200 m2, for a total volume of 315,700 m3. Our work firstly combines acoustic survey techniques and geomorphometric analysis to develop innovative approaches for eco-geomorphological studies. The obtained results can contribute to a better definition of the ocean carbon budget, and to the monitoring of local anthropogenic impacts (e.g., bottom trawling damage) and global changes, like ocean warming and acidification. These can affect the structural complexity and total volume of carbonate deposits characterizing the Mediterranean benthic environment.

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.

scholarly journals Rapid relative increase of crustose coralline algae following herbivore exclusion in a reef of El Salvador

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10696
Author(s):  
Xochitl E. Elías Ilosvay ◽  
Johanna Segovia ◽  
Sebastian Ferse ◽  
Walter Ernesto Elias ◽  
Christian Wild
Keyword(s):  
El Salvador ◽  
Benthic Community ◽  
Anthropogenic Impacts ◽  
Coral Cover ◽  
Benthic Algae ◽  
Coralline Algae ◽  
Crustose Coralline Algae ◽  
Night Time ◽  
Herbivore Exclusion ◽  
Turf Algae

The Eastern Tropical Pacific (ETP) is one of the most isolated and least studied regions in the world. This particularly applies to the coast of El Salvador, where the only reef between Guatemala and Nicaragua, called Los Cóbanos reef, is located. There is very little published information about the reef’s biodiversity, and to our knowledge, no research on its ecology and responses to anthropogenic impacts, such as overfishing, has been conducted. The present study, therefore, described the benthic community of Los Cóbanos reef, El Salvador, using the Line-Point-Intercept-Transect method and investigated changes in the benthic community following the exclusion of piscine macroherbivores over a period of seven weeks. Results showed high benthic algae cover (up to 98%), dominated by turf and green algae, and low coral cover (0–4%). Porites lobata was the only hermatypic coral species found during the surveys. Surprisingly, crustose coralline algae (CCA) showed a remarkable total cover increase by 58%, while turf algae cover decreased by 82%, in experimental plots after seven weeks of piscine macroherbivore exclusion. These findings apparently contradict the results of most previous similar studies. While it was not possible to ascertain the exact mechanisms leading to these drastic community changes, the most likely explanation is grazing on turf by small grazing macroherbivores that had access to the cages during the experiment and clearing of CCA initially covered by epiphytes and sediments. A higher CCA cover would promote the succesful settlement by corals and prevent further erosion of the reef framework. Therefore it is crucial to better understand algal dynamics, herbivory, and implications of overfishing at Los Cóbanos to avoid further reef deterioration. This could be achieved through video surveys of the fish community, night-time observations of the macroinvertebrate community, exclusion experiments that also keep out herbivorous macroinvertebrates, and/or experimental assessments of turf algae/CCA interactions.

scholarly journals The collapse of marine forests: drastic reduction in populations of the family Sargassaceae in Madeira Island (NE Atlantic)

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Alejandro Bernal-Ibáñez ◽  
Ignacio Gestoso ◽  
Peter Wirtz ◽  
Manfred Kaufmann ◽  
Ester A. Serrão ◽  
...  
Keyword(s):  
Sea Urchins ◽  
Anthropogenic Impacts ◽  
Benthic Communities ◽  
Coralline Algae ◽  
North Coast ◽  
Anthropogenic Pressure ◽  
Historical Records ◽  
Crustose Coralline Algae ◽  
Ne Atlantic ◽  
Madeira Island

AbstractSpecies of the genera Cystoseira, Ericaria, Gongolaria, and Sargassum (family Sargassaceae) are key components of the Mediterranean-Atlantic marine forests, essential for biodiversity and ecosystem functioning. Populations of these foundational species are particularly vulnerable to anthropogenic impacts, likely to be intensified under future scenarios of climate change. The decline and even disappearance of these species have been reported in different areas of the world. At Madeira Island (NE Atlantic), populations of Gongolaria abies-marina, Ericaria selaginoides, Sargassum vulgare, and Sargassum filipendula, the most ecologically relevant species in Macaronesian marine forests, have been suffering a drastic decline during the last decades, especially on the southern coast of the island, where anthropogenic pressure is higher than on the north coast. The lack of sufficient temporal coverage on qualitative and quantitative studies of Sargassaceae communities in Madeira poses a challenge to establish a specific period for this decline. Consulting qualitative studies and historical records, we have set for the first time a timeline that shows an evident decrease in Sargassaceae populations in the last 20 years on Madeira Island. Following this timeline, we pinpoint the start of this decline in the first decade of the 2000s. This can be particularly confirmed for places like Funchal and Reis Magos, with significantly higher historical records. Currently, most benthic communities on shallow subtidal rocky reefs along the south coast are dominated by sea urchins and crustose coralline algae, the so-called sea urchin barrens. However, in some cases, they are entirely covered by a layer of sediment. We discuss the possible factors contributing to these drastic changes, bringing Madeira’s marine forests to a dramatic decline. As many animal species rely on marine forests, the decline of Sargassaceae populations represents an invaluable ecological loss for the coastal ecosystem of the island.

scholarly journals Bioerosion of reef-building crustose coralline algae by endolithic invertebrates in an upwelling-influenced reef

Coral Reefs ◽  
2021 ◽  
Author(s):  
Alexandra Ramírez-Viaña ◽  
Guillermo Diaz-Pulido ◽  
Rocío García-Urueña
Keyword(s):  
Coralline Algae ◽  
Crustose Coralline Algae

scholarly journals How Perceptions of Trust, Risk, Tap Water Quality, and Salience Characterize Drinking Water Choices

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 49
Author(s):  
Madeline A. Grupper ◽  
Madeline E. Schreiber ◽  
Michael G. Sorice
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Risk Perceptions ◽  
Anthropogenic Impacts ◽  
Tap Water ◽  
Water Utilities ◽  
Global Changes ◽  
Water Utility ◽  
The Public ◽  
Water Behavior

Provision of safe drinking water by water utilities is challenged by disturbances to water quality that have become increasingly frequent due to global changes and anthropogenic impacts. Many water utilities are turning to adaptable and flexible strategies to allow for resilient management of drinking water supplies. The success of resilience-based management depends on, and is enabled by, positive relationships with the public. To understand how relationships between managers and communities spill over to in-home drinking water behavior, we examined the role of trust, risk perceptions, salience of drinking water, and water quality evaluations in the choice of in-home drinking water sources for a population in Roanoke Virginia. Using survey data, our study characterized patterns of in-home drinking water behavior and explored related perceptions to determine if residents’ perceptions of their water and the municipal water utility could be intuited from this behavior. We characterized drinking water behavior using a hierarchical cluster analysis and highlighted the importance of studying a range of drinking water patterns. Through analyses of variance, we found that people who drink more tap water have higher trust in their water managers, evaluate water quality more favorably, have lower risk perceptions, and pay less attention to changes in their tap water. Utility managers may gauge information about aspects of their relationships with communities by examining drinking water behavior, which can be used to inform their future interactions with the public, with the goal of increasing resilience and adaptability to external water supply threats.

Quantitative Content Analysis of the United Nations Seabed Debate: Methodology and a Continental Shelf Case Study

1970 ◽  
Vol 24 (3) ◽  
pp. 479-502 ◽  
Author(s):  
R. L. Friedheim ◽  
J. B. Kadane
Keyword(s):  
United Nations ◽  
Continental Shelf ◽  
Ad Hoc ◽  
Mineral Resources ◽  
Outer Edge ◽  
General Assembly ◽  
Wide Range ◽  
The Subject ◽  
The United Nations

International arrangements for the uses of the ocean have been the subject of long debate within the United Nations since a speech made by Ambassador Arvid Pardo of Malta before the General Assembly in 1967. Issues in question include the method of delimiting the outer edge of the legal continental shelf; the spectrum of ocean arms control possibilities; proposals to create a declaration of principles governing the exploration for, and the exploitation of, seabed mineral resources with the promise that exploitation take place only if it “benefits mankind as a whole,” especially the developing states; and consideration of schemes to create international machinery to regulate, license, or own the resources of the seabed and subsoil. The discussions and debates began in the First (Political and Security) Committee of the 22nd General Assembly and proceeded through an ad hoc committee to the 23rd and 24th assembly plenary sessions. The creation of a permanent committee on the seabed as a part of the General Assembly's machinery attests to the importance members of the United Nations attribute to ocean problems. Having established the committee, they will be faced soon with the necessity of reaching decisions. The 24th General Assembly, for example, passed a resolution requesting the Secretary-General to ascertain members' attitudes on the convening of a new international conference to deal with a wide range of law of the sea problems.

scholarly journals Involving fishers in scaling up the restoration of cold-water coral gardens on the Mediterranean continental shelf

2021 ◽  
Vol 262 ◽  
pp. 109301
Author(s):  
Maria Montseny ◽  
Cristina Linares ◽  
Núria Viladrich ◽  
Marina Biel ◽  
Nuno Gracias ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Cold Water ◽  
Scaling Up ◽  
The Mediterranean ◽  
Water Coral

Synergistic effects of diuron and sedimentation on photosynthesis and survival of crustose coralline algae

2005 ◽  
Vol 51 (1-4) ◽  
pp. 415-427 ◽  
Author(s):  
Lindsay Harrington ◽  
Katharina Fabricius ◽  
Geoff Eaglesham ◽  
Andrew Negri
Keyword(s):  
Synergistic Effects ◽  
Coralline Algae ◽  
Crustose Coralline Algae

Effect of 3D printer enabled surface morphology and composition on coral growth in artificial reefs

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ilse Valenzuela Matus ◽  
Jorge Lino Alves ◽  
Joaquim Góis ◽  
Augusto Barata da Rocha ◽  
Rui Neto ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Chemical Composition ◽  
Chemical Elements ◽  
Three Dimensional ◽  
Coral Growth ◽  
Coralline Algae ◽  
Textured Surface ◽  
Crustose Coralline Algae ◽  
Statistical Parameters ◽  
Content Type

Purpose The purpose of this paper is to prove and qualify the influence of textured surface substrates morphology and chemical composition on the growth and propagation of transplanted corals. Use additive manufacturing and silicone moulds for converting three-dimensional samples into limestone mortar with white Portland cement substrates for coral growth. Design/methodology/approach Tiles samples were designed and printed with different geometries and textures inspired by nature marine environment. Commercial coral frag tiles were analysed through scanning electron microscopy (SEM) to identify the main chemical elements. Raw materials and coral species were selected. New base substrates were manufactured and deployed into a closed-circuit aquarium to monitor the coral weekly evolution process and analyse the results obtained. Findings Experimental results provided positive statistical parameters for future implementation tests, concluding that the intensity of textured surface, interfered favourably in the coralline algae biofilm growth. The chemical composition and design of the substrates were determinant factors for successful coral propagation. Recesses and cavities mimic the natural rocks aspect and promoted the presence and interaction of other species that favour the richness of the ecosystem. Originality/value Additive manufacturing provided an innovative method of production for ecology restoration areas, allowing rapid prototyping of substrates with high complexity morphologies, a critical and fundamental attribute to guarantee coral growth and Crustose Coralline Algae. The result of this study showed the feasibility of this approach using three-dimensional printing technologies.

The Agreement between Greece and Italy on the Delimitation of their Respective Maritime Zones: An Italian Perspective

2021 ◽  
Vol 30 (1) ◽  
pp. 283-294
Author(s):  
Marina Mancini
Keyword(s):  
Continental Shelf ◽  
International Law ◽  
The Other ◽  
Boundary Line ◽  
Great Success ◽  
Ionian Sea ◽  
National Interests ◽  
The Mediterranean

In 2020 Greece and Italy concluded a maritime delimitation agreement, extending the already-established boundary line between their respective continental shelf areas to the other maritime areas to which they are entitled under international law. The Greek authorities hailed the agreement as a great success, stressing that it fully reflects their position vis-à-vis maritime delimitation in the Mediterranean and it meets their national interests in the Ionian Sea. This article critically analyzes the agreement, in the light of various recent events, and it finds that it serves Italian interests too. In particular, the 2020 Italo-Greek agreement furthers Italy’s growing interest in delimiting the maritime zones to which it is entitled under international law, so as to prevent its rights and jurisdiction over them being impaired by the proclamation of overlapping zones by its neighbours. It also sets the stage for future proclamation by Italy of an EEZ covering the waters adjacent to its territorial sea in the Ionian Sea.

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