CoBOP Coral Reefs: Optical Closure of a Coral Reef Submarine Light Field

2001 ◽  
Author(s):  
Charles S. Yentsch ◽  
David A. Phinney
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Light Field

Prominence of environmental and anthropogenic agents on the occurrence of coral reef bleaching syndrome and coral diseases

2024 ◽  
Vol 74 (10) ◽  
pp. 6139-2024
Author(s):  
MICHAŁ SCHULZ ◽  
ALEKSANDRA ŁOŚ ◽  
PATRYCJA SKOWRONEK ◽  
ANETA STRACHECKA
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Oil Spills ◽  
Global Scale ◽  
Ecological Processes ◽  
Coral Diseases ◽  
Rapid Changes ◽  
Anthropogenic Threats ◽  
Negative Factors ◽  
Main Relationship

Coral reefs are the most productive ecosystems on Earth. They ensure the conservation of biodiversity and are a live habitat for 25% of all marine organisms. The main relationship on the coral reef is the symbiosis between corals and algae from the genus Symbiodinium (commonly called zooxanthellae). The authors of this publication have characterized and described the factors limiting the occurrence of coral reefs, including: water temperature, salinity, access to sunlight, contamination, physicochemical and hydromechanical parameters of water. Moreover anthropogenic threats to coral reefs have been specified, including diving tourism, ecological disasters (e.g. oil spills) and the development of marine aquaristics. Rapid changes in the basic living conditions are dangerous for corals and their symbionts and may cause the unsuitability of the new environment resulting in diseases such as coral bleaching. Corals bleaching is a disease associated with the break of the coral and algae relationship which results in a coral reef death on a global scale. Awareness of these negative factors, often related to human activity, may allow us to better understand the ecological processes that are the basis of reef functioning and might enable us to prevent and oppose to the changes and ecological recessions of coral reefs.

scholarly journals Turbid Coral Reefs: Past, Present and Future—A Review

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 251
Author(s):  
Adi Zweifler (Zvifler) ◽  
Michael O’Leary ◽  
Kyle Morgan ◽  
Nicola K. Browne
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Coral Reefs ◽  
Environmental Change ◽  
Scientific Literature ◽  
Conservation Status ◽  
Climate Change Impacts ◽  
Geographic Range ◽  
Reef Complex ◽  
Sediment Input

Increasing evidence suggests that coral reefs exposed to elevated turbidity may be more resilient to climate change impacts and serve as an important conservation hotspot. However, logistical difficulties in studying turbid environments have led to poor representation of these reef types within the scientific literature, with studies using different methods and definitions to characterize turbid reefs. Here we review the geological origins and growth histories of turbid reefs from the Holocene (past), their current ecological and environmental states (present), and their potential responses and resilience to increasing local and global pressures (future). We classify turbid reefs using new descriptors based on their turbidity regime (persistent, fluctuating, transitional) and sources of sediment input (natural versus anthropogenic). Further, by comparing the composition, function and resilience of two of the most studied turbid reefs, Paluma Shoals Reef Complex, Australia (natural turbidity) and Singapore reefs (anthropogenic turbidity), we found them to be two distinct types of turbid reefs with different conservation status. As the geographic range of turbid reefs is expected to increase due to local and global stressors, improving our understanding of their responses to environmental change will be central to global coral reef conservation efforts.

scholarly journals Stokes drift through corals

2021 ◽  
Author(s):  
Joseph J. Webber ◽  
Herbert E. Huppert
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Porous Layer ◽  
Large Scale ◽  
Fluid Layer ◽  
Ocean Waves ◽  
Stokes Drift ◽  
Inviscid Fluid ◽  
Porous Bed ◽  
Vertical Drift

AbstractMotivated by shallow ocean waves propagating over coral reefs, we investigate the drift velocities due to surface wave motion in an effectively inviscid fluid that overlies a saturated porous bed of finite depth. Previous work in this area either neglects the large-scale flow between layers (Phillips in Flow and reactions in permeable rocks, Cambridge University Press, Cambridge, 1991) or only considers the drift above the porous layer (Monismith in Ann Rev Fluid Mech 39:37–55, 2007). Overcoming these limitations, we propose a model where flow is described by a velocity potential above the porous layer and by Darcy’s law in the porous bed, with derived matching conditions at the interface between the two layers. Both a horizontal and a novel vertical drift effect arise from the damping of the porous bed, which requires the use of a complex wavenumber k. This is in contrast to the purely horizontal second-order drift first derived by Stokes (Trans Camb Philos Soc 8:441–455, 1847) when working with solely a pure fluid layer. Our work provides a physical model for coral reefs in shallow seas, where fluid drift both above and within the reef is vitally important for maintaining a healthy reef ecosystem (Koehl et al. In: Proceedings of the 8th International Coral Reef Symposium, vol 2, pp 1087–1092, 1997; Monismith in Ann Rev Fluid Mech 39:37–55, 2007). We compare our model with field measurements by Koehl and Hadfield (J Mar Syst 49:75–88, 2004) and also explain the vertical drift effects as documented by Koehl et al. (Mar Ecol Prog Ser 335:1–18, 2007), who measured the exchange between a coral reef layer and the (relatively shallow) sea above.

scholarly journals Can we measure beauty? Computational evaluation of coral reef aesthetics

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1390 ◽  
Author(s):  
Andreas F. Haas ◽  
Marine Guibert ◽  
Anja Foerschner ◽  
Tim Co ◽  
Sandi Calhoun ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Local Population ◽  
Machine Learning Algorithms ◽  
Monitoring Tool ◽  
Photographic Images ◽  
Aesthetic Appearance ◽  
The Aesthetic ◽  
Monitoring Protocols ◽  
Aesthetic Values

The natural beauty of coral reefs attracts millions of tourists worldwide resulting in substantial revenues for the adjoining economies. Although their visual appearance is a pivotal factor attracting humans to coral reefs current monitoring protocols exclusively target biogeochemical parameters, neglecting changes in their aesthetic appearance. Here we introduce a standardized computational approach to assess coral reef environments based on 109 visual features designed to evaluate the aesthetic appearance of art. The main feature groups include color intensity and diversity of the image, relative size, color, and distribution of discernable objects within the image, and texture. Specific coral reef aesthetic values combining all 109 features were calibrated against an established biogeochemical assessment (NCEAS) using machine learning algorithms. These values were generated for ∼2,100 random photographic images collected from 9 coral reef locations exposed to varying levels of anthropogenic influence across 2 ocean systems. Aesthetic values proved accurate predictors of the NCEAS scores (root mean square error < 5 forN≥ 3) and significantly correlated to microbial abundance at each site. This shows that mathematical approaches designed to assess the aesthetic appearance of photographic images can be used as an inexpensive monitoring tool for coral reef ecosystems. It further suggests that human perception of aesthetics is not purely subjective but influenced by inherent reactions towards measurable visual cues. By quantifying aesthetic features of coral reef systems this method provides a cost efficient monitoring tool that targets one of the most important socioeconomic values of coral reefs directly tied to revenue for its local population.

scholarly journals Using virtual reality to estimate aesthetic values of coral reefs

2018 ◽  
Vol 5 (4) ◽  
pp. 172226 ◽  
Author(s):  
Julie Vercelloni ◽  
Sam Clifford ◽  
M. Julian Caley ◽  
Alan R. Pearse ◽  
Ross Brown ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Structural Complexity ◽  
Natural Environments ◽  
Natural Ecosystems ◽  
Aesthetic Value ◽  
Natural Systems ◽  
Holistic Conservation ◽  
Past Experiences ◽  
Aesthetic Values

Aesthetic value, or beauty, is important to the relationship between humans and natural environments and is, therefore, a fundamental socio-economic attribute of conservation alongside other ecosystem services. However, beauty is difficult to quantify and is not estimated well using traditional approaches to monitoring coral-reef aesthetics. To improve the estimation of ecosystem aesthetic values, we developed and implemented a novel framework used to quantify features of coral-reef aesthetics based on people's perceptions of beauty. Three observer groups with different experience to reef environments (Marine Scientist, Experienced Diver and Citizen) were virtually immersed in Australian's Great Barrier Reef (GBR) using 360° images. Perceptions of beauty and observations were used to assess the importance of eight potential attributes of reef-aesthetic value. Among these, heterogeneity, defined by structural complexity and colour diversity, was positively associated with coral-reef-aesthetic values. There were no group-level differences in the way the observer groups perceived reef aesthetics suggesting that past experiences with coral reefs do not necessarily influence the perception of beauty by the observer. The framework developed here provides a generic tool to help identify indicators of aesthetic value applicable to a wide variety of natural systems. The ability to estimate aesthetic values robustly adds an important dimension to the holistic conservation of the GBR, coral reefs worldwide and other natural ecosystems.

scholarly journals Les rivages des Bermudes et les formes littorales de dissolution du calcaire

2005 ◽  
Vol 2 (2) ◽  
pp. 115-137 ◽  
Author(s):  
François Taillefer
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Mechanical Action ◽  
Intermediate Position ◽  
Striking Feature ◽  
Tidal Range ◽  
Intermediate Type ◽  
North East ◽  
The North

The littoral morphology of the Bermudas is an erosional morphology in limestones, the main processes being mechanical action and solution. The temperatures, in January and February, of the waters washing the Bermudas, are low enough to prevent the growing of true coral reefs. Therefore, it is not the morphology of a coral reef. The predominance of wave-cut cliffs is the most striking feature, despite the low and gently rolling topography. There are, however, other types of coasts on the islands, the mangrove being found on many sheltered shores. The writer thus opposes the sheltered shores of the sounds to the ones exposed on the southcoast, while the shores of the north and north-east coasts belong to an intermediate type. The steplike arrangement of the coastal forms of solution of the Bermudas limestones is primarily linked to the amount of the tidal range. These features are similar to those described on the shores of the warm seas, where the tide is negligible or weak. The Bermudas occupy an intermediate position between the regions where reefs are built by corals, and those, to the north, where solution, helped by other processes, occurs without compensation.

scholarly journals Measuring Sound at a Cold-Water Coral Reef to Assess the Impact of COVID-19 on Noise Pollution

2021 ◽  
Vol 8 ◽  
Author(s):  
Laurence H. De Clippele ◽  
Denise Risch
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Sea Level ◽  
Cold Water ◽  
Noise Pollution ◽  
Ecosystem Functions ◽  
Noise Levels ◽  
Level Height ◽  
Water Coral

This study compares the noise levels at the cold-water coral Tisler reef, before and after the closure of the border between Norway and Sweden, which occurred as a direct result of the COVID-19 pandemic. The Tisler reef is a marine protected area located under a ferry “highway” that connects Norway and Sweden. Cold-water coral reefs are recognised as being important hotspots of both biodiversity and biomass, they function as breeding and nursing grounds for commercially important fish and are essential in providing ecosystem functions. Whilst studies have shown that fishery, ocean warming, and acidification threaten them, the effects of noise pollution on cold-water coral reefs remains unstudied. To study the severity of noise pollution at the Tisler reef, a long-term acoustic recorder was deployed from 29 January 2020 until 26 May 2020. From 15 March COVID-19 lockdown measures stopped passenger vessel traffic between Norway and Sweden. This study found that the overall noise levels were significantly lower after border closure, due to reduced ferry traffic, wind speeds, and sea level height. When comparing the median hourly noise levels of before vs. after border closure, this study measured a significant reduction in the 63–125 Hz 1/3 octave band noise levels of 8.94 ± 0.88 (MAD) dB during the day (07:00:00–19:59:59) and 1.94 ± 0.11 (MAD) dB during the night (20:00:00–06:59:59). Since there was no ferry traffic during the night, the drop in noise levels at night was likely driven by seasonal changes, i.e., the reduction in wind speed and sea level height when transitioning from winter to spring. Taking into account this seasonal effect, it can be deduced that the COVID-19 border closure reduced the noise levels in the 63–125 Hz 1/3 octave bands at the Tisler reef by 7.0 ± 0.99 (MAD) dB during the day. While the contribution of, and changes in biological, weather-related and geophysical sound sources remain to be assessed in more detail, understanding the extent of anthropogenic noise pollution at the Tisler cold-water coral reef is critical to guide effective management to ensure the long-term health and conservation of its ecosystem functions.

scholarly journals Experimental reef communities persist under future ocean acidification and warming

2021 ◽  
Author(s):  
Christopher Jury ◽  
Keisha Bahr ◽  
Evan Barba ◽  
Russell Brainard ◽  
Annick Cros ◽  
...  
Keyword(s):  
Experimental Study ◽  
Species Richness ◽  
Coral Reef ◽  
Coral Reefs ◽  
Ocean Acidification ◽  
Community Composition ◽  
Functional State ◽  
Reef Communities ◽  
Paris Climate Agreement

Abstract Coral reefs are among the most sensitive ecosystems affected by ocean acidification and warming, and are predicted to shift from net accreting calcifier-dominated systems to net eroding algal-dominated systems over the coming decades. Here we present a long-term experimental study examining the responses of entire mesocosm coral reef communities to acidification (-0.2 pH units), warming (+ 2°C), and combined future ocean (-0.2 pH, + 2°C) treatments. We show that under future ocean conditions, net calcification rates declined yet remained positive, corals showed reduced abundance yet were not extirpated, and community composition shifted while species richness was maintained. Our results suggest that under Paris Climate Agreement targets, coral reefs could persist in an altered functional state rather than collapse.

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