The scientific issues surrounding remote detection of submerged coral ecosystems

1998 ◽  
Vol 22 (2) ◽  
pp. 190-221 ◽  
Author(s):  
Heather Holden ◽  
Ellsworth LeDrew
Keyword(s):  
Remote Sensing ◽  
Coral Reef ◽  
Coral Reefs ◽  
Large Scale ◽  
Aerial Photographs ◽  
Coastal Zones ◽  
Global Status ◽  
Coral Reef Ecosystems ◽  
Remote Estimation

According to the 1993 colloquium on the ‘Global status of coral reefs', our understanding of the global role of coral reefs is inadequate. To increase our understanding, an accurate large-scale mapping and monitoring programme is necessary. Historically, coastal zones have been mapped using traditional surveying tools such as topographic maps, nautical charts, existing aerial photographs and direct observations. Although less expensive than digital imagery, exclusive use of these traditional tools may not be practical for monitoring large or remote coral reef ecosystems accurately. Researchers are attempting to develop an adequate coral reef mapping system based on digital remote sensing, but are impeded by issues such as effects of the intervening water column and spectral distinction of bottom types. The two variables discussed, which will contribute to our understanding of the global role of coral reefs, are: 1) remote sensing of submerged coral reefs in general; and 2) remote sensing of coral bleaching in particular. A summary of radiative transfer theory is presented and case studies of attempts at mapping remotely the geographic extent and health of submerged ecosystems, as well as a discussion of the remote estimation of water depth and quality. Problems in the translation and delivery of information to the end user are presented, and possible solutions suggested.

scholarly journals Coral reef monitoring in Panjang Island, Central Bangka

2021 ◽  
Vol 926 (1) ◽  
pp. 012099
Author(s):  
W Adi ◽  
I Akhrianti ◽  
M Hudatwi
Keyword(s):  
Remote Sensing ◽  
Coral Reef ◽  
Coral Reefs ◽  
Satellite Imagery ◽  
Good Condition ◽  
Aerial Photographs ◽  
Visual Interpretation ◽  
Composite Band ◽  
Sentinel 2A ◽  
Color Composite

Abstract Bangka Island is the largest tin producer in Indonesia and since the granting of tin mining freedom in 2000, unconventional tin mining (TI) is increasingly prevalent. The existence of mining activities will directly or indirectly damage the environment both on land and at sea. Especially the high biodiversity of coral reef ecosystem. The purpose of this research was to analyze a map of the distribution of coral reef based on Sentinel 2A satellite imagery data. Analyze the extent of the coral reefs in shallow waters of Putri Island, and analyze of the condition coral reefs (percentage cover, mortality index and genus diversity) with using collaboration betwen the coral diving data and remote sensing data. Studies of changes in coral reef ecosystems have been ongoing since several decades ago. The combination of satellite imagery and aerial photographs is capable of making long-term and continuous observations on mapping and change detection. Remote sensing technology has several advantages overconventional sampling to monitor a large area in time almost simultaneously and continuously including the difficult to explore areas. This research was conducted with visual interpretation by using standard true color composite band (483) and false color composite band (843) of Sentinel 2A and also using lyzenga transformation. Estimation of coral reefs area based on result is 475,96 ha (2016) and decreased to 475 ha (2021). The condition of coral reefs at the research location is a good condition.

Altered States: What Will Coral Reefs Look Like in the Future?

2011 ◽  
Vol 17 ◽  
pp. 131-137
Author(s):  
Joanie A. Kleypas
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Coral Reefs ◽  
Ocean Acidification ◽  
Large Scale ◽  
Altered States ◽  
Starting Point ◽  
The Future ◽  
Coral Reef Ecosystems ◽  
Bounce Back

Future environmental conditions for coral reefs are rapidly approaching states outside the ranges reefs have experienced for thousands to millions of years. Coral reef ecosystems, once thought to be robust to climate change because of their ability to bounce back after large scale physical impacts, have proven to be sensitive to both temperature rise and ocean acidification. Predicting what coral reefs will look like in the future is not an easy task, and one that is likely to be proven flawed. The discussion presented here is a starting point for those predictions, mostly from the perspective of reef building and ocean acidification.

scholarly journals PENYEBARAN BULU BABI (Sea Urchins) DI PERAIRAN PULAU MENJANGAN KECIL, KEPULAUAN KARIMUNJAWA, JEPARA

2018 ◽  
Vol 6 (3) ◽  
pp. 230-238
Author(s):  
Fitria Hersiana Afifa ◽  
Supriharyono Supriharyono ◽  
Pujiono Wahyu Purnomo
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Sea Urchins ◽  
Dispersion Index ◽  
Coral Reef Ecosystem ◽  
Dispersal Patterns ◽  
Coral Reef Ecosystems ◽  
Spread Pattern ◽  
Different Depths

ABSTRAK Echinodermata merupakan salah satu phylum yang memiliki peranan penting di perairan terumbu karang, seperti ditemukan di Perairan Pulau Menjangan Kecil. Peranan Bulu Babi di ekosistem terumbu karang berkaitan dengan pengendalian ekspansi algae. Penelitian dilaksanakan pada tanggal 19 dan 20 November 2016, dengan tujuan untuk mengetahui penyebaran Bulu Babi serta kelimpahan Bulu Babi pada kedalaman dan antar lokasi yang berbeda. Metode yang digunakan adalah metode eksplanatif. Stasiun pengukuran terdapat di zona muka dan belakang pulau yang terdapat terumbu karang, masing-masing stasiun dengan kedalaman yang berbeda. Pola penyebaran Bulu Babi dapat diketahui menggunakan formula ID= S2/  , berdasarkan rumus tersebut diketahui nilai ID (indeks dispersion) tiap kedalaman di dua lokasi yang berbeda. Hasil ID pada Lokasi A berbeda pada kedalaman 0-90cm dan 90-140cm ID < 1, sedangkan kedalaman 140-170cm dan >170cm ID > 1. Hasil ID lokasi B pada empat kedalaman yang berbeda yaitu ID>1. Berdasarkan hasil ID tersebut dapat diketahui bagaimana pola penyebaran. Hal ini menunjukkan bahwa Bulu Babi di Pulau Menjangan Kecil sebagian besar hidup mengelompok pada kedalaman yang ekosistem terumbu karang masih cukup baik. Kata Kunci: Pulau Menjangan Kecil; Penyebaran; Kelimpahan; Bulu Babi ABSTRACT Echinoderm is one of the phylum that has an important role in the waters of the coral reefs, as found in the waters of the Menjangan Kecil Island. The role of the sea urchins in the coral reef ecosystem is related to the control of algae expansion. The study was conducted in 19th  and 20th  November 2016, with the objective of knowing the spread abundance of sea urchins at different depths and locations. The method that used was explanative method. The measuring stations are located in the back and forth zones of coral reefs, each with different depths. Spread pattern of sea urchins can be known using the formula ID = S2 / x ̅, based on the formula is known value of ID (dispersion index) each depth at two different location. Result ID at Location A at 0-90 cm and 90-140 cm is ID <1, while at 140-170 cm and > 170 cm is ID> 1. The result of location ID B on four different depths is ID> 1. Based on the ID results can be known how the pattern of dissemination. This indicates that the sea urchins in Menjangan Kecil Island live mostly in groups at the depths of which coral reef ecosystems are still quite good. Keywords: Menjangan Kecil Island; Dispersal patterns; Abundanc;  Sea Urchins

Tropical Climate Variability and Coral Reefs - A Past to Future Perspective on Current Rates of Change at Ultra-High Resolution

2021 ◽  
Author(s):  
Thomas Felis ◽  
Miriam Pfeiffer
Keyword(s):  
Coral Reef ◽  
High Resolution ◽  
Coral Reefs ◽  
Climate Variability ◽  
Large Scale ◽  
Tropical Climate ◽  
Future Perspective ◽  
Rates Of Change ◽  
Coral Reef Ecosystems ◽  
Warming World

&lt;p&gt;Climate change, in particular the rise in tropical sea surface temperatures, is the greatest threat to coral reef ecosystems today and causes climatic extremes affecting the livelihood of tropical societies. The combination of long-term global warming and interannual El Ni&amp;#241;o-related warm events has severely affected corals and coral reefs throughout the tropical ocean basins. Mass coral bleaching, a result of large-scale temperature stress, was first observed during the 1982/83 El Ni&amp;#241;o, and was followed by much more severe, global scale bleaching events during the El Ni&amp;#241;o years of 1997/98 and 2010, culminating in the most wide-spread and most destructive global bleaching episode to date, which lasted from 2014-2017. The interval between recurrent mass coral bleaching events driven by anomalously high sea surface temperatures is becoming too short for a full recovery of mature coral reef assemblages and will have dramatic effects on future coral reef growth. Assessing how future warming will change coral reef ecosystems and tropical climate variability is therefore of extreme urgency.&lt;/p&gt;&lt;p&gt;The recently established Priority Programme &amp;#8222;Tropical Climate Variability and Coral Reefs &amp;#8211; A Past to Future Perspective on Current Rates of Change at Ultra-High Resolution&amp;#8220; (SPP 2299; https://www.spp2299.tropicalclimatecorals.de/) of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) aims to enhance our current understanding of tropical marine climate variability and its impact on coral reef ecosystems in a warming world, by quantifying climatic and environmental changes during both the ongoing warming and past warm periods on timescales relevant for society. Ultra-high resolution coral geochemistry provides a tool to understand the temporal response of corals and coral reefs to ongoing climate and environmental change, to reconstruct past tropical climate and environmental variability and to use these data in conjunction with advanced statistical methods, earth system modelling and observed ecosystem responses for improved projections of future changes in tropical climate and coral reef ecosystems.&lt;/p&gt;&lt;p&gt;The Priority Programme is organised around three major research topics in order to fuel interdisciplinary collaboration among various disciplines: (a) Large-scale ocean, climate &amp; environment reconstructions, (b) Coral &amp; reef-scale response to current environmental stress, and (c) Climate, reef &amp; proxy modelling &amp;#8211; Climate &amp; proxy advanced statistics. The strongly interdisciplinary Priority Programme will bring together expertise in the fields of climate, environmental and ecosytem research in a sustainable manner, and aims to provide an ultra-high resolution past to future perspective on current rates of change to project how tropical marine climate variability and coral reef ecosystems will change in a warming world.&lt;/p&gt;

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 Reconstructing High-Precision Coral Reef Geomorphology from Active Remote Sensing Datasets: A Robust Spatial Variability Modified Ordinary Kriging Method

2022 ◽  
Vol 14 (2) ◽  
pp. 253
Author(s):  
Qi Wang ◽  
Han Xiao ◽  
Wenzhou Wu ◽  
Fenzhen Su ◽  
Xiuling Zuo ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Coral Reef ◽  
Coral Reefs ◽  
Spatial Variability ◽  
High Precision ◽  
Ordinary Kriging ◽  
Surface Model ◽  
Smoothing Effect ◽  
Geomorphological Parameters ◽  
Reef Geomorphology

Active remote sensing technology represented by multi-beam and lidar provides an important approach for the effective acquisition of underwater coral reef geomorphological information. A spatially continuous surface model of coral reef geomorphology reconstructed from active remote sensing datasets can provide important geomorphological parameters for the research of coral reef geomorphological and ecological changes. However, the surface modeling methods commonly used in previous studies, such as ordinary kriging (OK) and natural neighborhood (NN), often represent a “smoothing effect”, which causes the strong spatial variability of coral reefs to be imprecisely reflected by the reconstructed surfaces, thus affecting the accurate calculation of subsequent geomorphological parameters. In this study, a spatial variability modified OK (OK-SVM) method is proposed to reduce the impact of the “smoothing effect” on the high-precision reconstruction of the complex geomorphology of coral reefs. The OK-SVM adopts a collaborative strategy of global parameter transformation, local residual correction, and extremum correction to modify the spatial variability of the reconstructed model, while maintaining high local accuracy. The experimental results show that the OK-SVM has strong robustness to spatial variability modification. This method was applied to the geomorphological reconstruction of the northern area of a coral atoll in the Nansha Islands, South China Sea, and the performance was compared with that of OK and NN. The results show that OK-SVM has higher numerical accuracy and attribute accuracy in detailed morphological fidelity, and is more adaptable in the geomorphological reconstruction of coral reefs with strong spatial variability. This method is relatively reliable for achieving high-precision reconstruction of complex geomorphology of coral reefs from active remote sensing datasets, and has potential to be extended to other geomorphological reconstruction applications.

scholarly journals Representative benthic habitat mapping on Lovina coral reefs in Northern Bali, Indonesia

2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Anggita Kartikasari ◽  
TODHI PRISTIANTO ◽  
RIZKI HANINTYO ◽  
EGHBERT ELVAN AMPOU ◽  
TEJA ARIEF WIBAWA ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Habitat Mapping ◽  
Benthic Habitat ◽  
Coral Rubble ◽  
Spatial Coverage ◽  
Coral Reef Ecosystems ◽  
Optical Imagery ◽  
Sentinel 2

Abstract. Kartikasari A, Pristianto T, Hanintyo R, Ampou EE, Wibawa TA, Borneo BB. 2021. Representative benthic habitat mapping on Lovina coral reefs in Northern Bali, Indonesia. Biodiversitas 22: 4766-4774. Satellite optical imagery datasets integrated with in situ measurements are widely used to derive the spatial distribution of various benthic habitats in coral reef ecosystems. In this study, an approach to estimate spatial coverage of those habitats based on observation derived from Sentinel-2 optical imagery and a field survey, is presented. This study focused on the Lovina coral reef ecosystem of Northern Bali, Indonesia to support deployment of artificial reefs within the Indonesian Coral Reef Garden (ICRG) programme. Three specific locations were explored: Temukus, Tukad Mungga, and Baktiseraga waters. Spatial benthic habitat coverages of these three waters was estimated based on supervised classification techniques using 10m bands of Sentinel-2 imagery and the medium scale approach (MSA) transect method of in situ measurement.The study indicates that total coverage of benthic habitat is 61.34 ha, 25.17 ha, and 27.88 ha for Temukus, Tukad Mungga, and Baktiseraga waters, respectively. The dominant benthic habitat of those three waters consists of sand, seagrass, coral, rubble, reef slope and intertidal zone. The coral reef coverage is 29.48 ha (48%) for Temukus covered by genus Acropora, Isopora, Porites, Montipora, Pocillopora. The coverage for Tukad Mungga is 8.69 ha (35%) covered by genus Acropora, Montipora, Favia, Psammocora, Porites, and the coverage for Baktiseraga is 11.37 ha (41%) covered by genus Montipora sp, Goniastrea, Pavona, Platygyra, Pocillopora, Porites, Acropora, Leptoseris, Acropora, Pocillopora, Fungia. The results are expected to be suitable as supporting data in restoring coral reef ecosystems in the northern part of Bali, especially in Buleleng District.

scholarly journals Divergence of seafloor elevation and sea level rise in coral reef ecosystems

2017 ◽  
Vol 14 (6) ◽  
pp. 1739-1772 ◽  
Author(s):  
Kimberly K. Yates ◽  
David G. Zawada ◽  
Nathan A. Smiley ◽  
Ginger Tiling-Range
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Sea Level Rise ◽  
Sea Level ◽  
Anthropogenic Impacts ◽  
Regional Scale ◽  
Coastal Hazards ◽  
Carbonate Production ◽  
Coral Reef Ecosystems ◽  
Study Sites

Abstract. Coral reefs serve as natural barriers that protect adjacent shorelines from coastal hazards such as storms, waves, and erosion. Projections indicate global degradation of coral reefs due to anthropogenic impacts and climate change will cause a transition to net erosion by mid-century. Here, we provide a comprehensive assessment of the combined effect of all of the processes affecting seafloor accretion and erosion by measuring changes in seafloor elevation and volume for five coral reef ecosystems in the Atlantic, Pacific, and Caribbean over the last several decades. Regional-scale mean elevation and volume losses were observed at all five study sites and in 77 % of the 60 individual habitats that we examined across all study sites. Mean seafloor elevation losses for whole coral reef ecosystems in our study ranged from −0.09 to −0.8 m, corresponding to net volume losses ranging from 3.4  ×  106 to 80.5  ×  106 m3 for all study sites. Erosion of both coral-dominated substrate and non-coral substrate suggests that the current rate of carbonate production is no longer sufficient to support net accretion of coral reefs or adjacent habitats. We show that regional-scale loss of seafloor elevation and volume has accelerated the rate of relative sea level rise in these regions. Current water depths have increased to levels not predicted until near the year 2100, placing these ecosystems and nearby communities at elevated and accelerating risk to coastal hazards. Our results set a new baseline for projecting future impacts to coastal communities resulting from degradation of coral reef systems and associated losses of natural and socioeconomic resources.

The Role of Symbioses in the Adaptation and Stress Responses of Marine Organisms

2020 ◽  
Vol 12 (1) ◽  
pp. 291-314 ◽  
Author(s):  
Amy Apprill
Keyword(s):  
Coral Reef ◽  
Significant Role ◽  
Stress Responses ◽  
Current Knowledge ◽  
Technological Development ◽  
Marine Organisms ◽  
Anthropogenic Change ◽  
Subject Knowledge ◽  
Coral Reef Ecosystems

Ocean ecosystems are experiencing unprecedented rates of climate and anthropogenic change, which can often initiate stress in marine organisms. Symbioses, or associations between different organisms, are plentiful in the ocean and could play a significant role in facilitating organismal adaptations to stressful ocean conditions. This article reviews current knowledge about the role of symbiosis in marine organismal acclimation and adaptation. It discusses stress and adaptations in symbioses from coral reef ecosystems, which are among the most affected environments in the ocean, including the relationships between corals and microalgae, corals and bacteria, anemones and clownfish, and cleaner fish and client fish. Despite the importance of this subject, knowledge of how marine organisms adapt to stress is still limited, and there are vast opportunities for research and technological development in this area. Attention to this subject will enhance our understanding of the capacity of symbioses to alleviate organismal stress in the oceans.

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