scholarly journals Using Remote Sensing and in situ Measurements for Efficient Mapping and Optimal Sampling of Coral Reefs

2021 ◽  
Vol 8 ◽  
Author(s):  
Alberto Candela ◽  
Kevin Edelson ◽  
Michelle M. Gierach ◽  
David R. Thompson ◽  
Gail Woodward ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Coral Reef ◽  
Coral Reefs ◽  
Decision Theory ◽  
Sample Selection ◽  
Global Scale ◽  
Global Mapping ◽  
And Performance ◽  
Reef Condition

Coral reefs are of undeniable importance to the environment, yet little is known of them on a global scale. Assessments rely on laborious, local in-water surveys. In recent years remote sensing has been useful on larger scales for certain aspects of reef science such as benthic functional type discrimination. However, remote sensing only gives indirect information about reef condition. Only through combination of remote sensing and in situ data can we achieve coverage to understand reef condition and monitor worldwide condition. This work presents an approach to global mapping of coral reef condition that intelligently selects local, in situ measurements that refine the accuracy and resolution of global remote sensing. To this end, we apply new techniques in remote sensing analysis, probabilistic modeling for coral reef mapping, and decision theory for sample selection. Our strategy represents a fundamental change in how we study coral reefs and assess their condition on a global scale. We demonstrate feasibility and performance of our approach in a proof of concept using spaceborne remote sensing together with high-quality airborne data from the NASA Earth Venture Suborbital-2 (EVS-2) Coral Reef Airborne Laboratory (CORAL) mission as a proxy for in situ samples. Results indicate that our method is capable of extrapolating in situ features and refining information from remote sensing with increasing accuracy. Furthermore, the results confirm that decision theory is a powerful tool for sample selection.

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 KONDISI IKAN KARANG FAMILI CHAETODONTIDAE DI DAERAH PERLINDUNGAN LAUT DESA BAHOI KECAMATAN LIKUPANG BARAT KABUPATEN MINAHASA UTARA

2015 ◽  
Vol 2 (3) ◽  
pp. 92
Author(s):  
Jacqline Laikun ◽  
Ari B Rondonuwu ◽  
Unstain N.W.J. Rembet
Keyword(s):  
Spatial Distribution ◽  
Coral Reef ◽  
Coral Reefs ◽  
Protected Areas ◽  
Reef Fish ◽  
Marine Protected Areas ◽  
Visual Census ◽  
Fish Family ◽  
Marine Life ◽  
Reef Condition

The coral reefs are a sundry of marine life. Which one is reef fish in family Chaetodontidae. This fish is  indicator of the coral reef condition. The aim from the research is : discover of spatial distribution of the reef fish family Chaetodontidae and find out of the intercourse of reef fish family Chaetodontidae with the coral reef presence based on growth of coral form. The research was do in the coral reef at Marine Protected Areas in Bahoi Village District of West Likupang North Minahasa Regency, on Tuesday, December 23rd, 2014. The research is using to do the surveying method. The data is collecting distribution of the fish Chaetodontidae (amount from species and individuals to using by technic visual census). The total of reef fish family Chaetodontidae those found in Marina Protected Areas in Bahoi Village is about 20 species, with total of the individuals at a depth of 3 meters and 10 meters is (56,66 and 57,33 individuals/150m2). Keywords : Coral reefs, Chaetodontidae, Bahoi   ABSTRAK Terumbu karang merupakan tempat berbagai macam biota laut. Salah satu Ikan karang adalah ikan famili Chaetodontidae. Ikan ini merupakan ikan indikator terumbu karang. Tujuan dari penelitian ini : mengetahui kelimpahan dari ikan karang famili Chaetodontidae. Penelitian ini dilakukan di Daerah Perlindungan Laut Desa Bahoi Kecamatan Likupang Barat Kabupaten Minahasa Utara, pada hari selasa, tanggal 23 Desember 2014. Penelitian ini menggunakan metode survey. Data yang dikumpulkan adalah kelimpahan ikan Chaetodontidae (Jumlah spesies dan individu dengan menggunakan teknik sensus visual). Jumlah ikan karang famili Chaetodontidae yang di temukan di Daerah Perlindungan Laut Desa Bahoi berjumlah 20 spesies, dengan jumlah individu pada kedalaman 3 meter dan 10 meter berjumlah (56,66 individu/150m2 dan 57,33/150m2 individu). Kata kunci : Terumbu karang, Chaetodontidae, Bahoi 1Bagian dari skripsi 2Mahasiswa Program Studi Manajemen Sumberdaya Perairan FPIK-UNSRAT 3Staf pengajar Fakultas Perikanan dan Ilmu Kelautan Universitas Sam Ratulangi

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 Global scale variability of the mineral dust long-wave refractive index: a new dataset of in situ measurements for climate modeling and remote sensing

2017 ◽  
Vol 17 (3) ◽  
pp. 1901-1929 ◽  
Author(s):  
Claudia Di Biagio ◽  
Paola Formenti ◽  
Yves Balkanski ◽  
Lorenzo Caponi ◽  
Mathieu Cazaunau ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Refractive Index ◽  
Size Distribution ◽  
Climate Models ◽  
Mineral Dust ◽  
Complex Refractive Index ◽  
Mineralogical Composition ◽  
Global Scale ◽  
Long Wave

Abstract. Modeling the interaction of dust with long-wave (LW) radiation is still a challenge because of the scarcity of information on the complex refractive index of dust from different source regions. In particular, little is known about the variability of the refractive index as a function of the dust mineralogical composition, which depends on the specific emission source, and its size distribution, which is modified during transport. As a consequence, to date, climate models and remote sensing retrievals generally use a spatially invariant and time-constant value for the dust LW refractive index. In this paper, the variability of the mineral dust LW refractive index as a function of its mineralogical composition and size distribution is explored by in situ measurements in a large smog chamber. Mineral dust aerosols were generated from 19 natural soils from 8 regions: northern Africa, the Sahel, eastern Africa and the Middle East, eastern Asia, North and South America, southern Africa, and Australia. Soil samples were selected from a total of 137 available samples in order to represent the diversity of sources from arid and semi-arid areas worldwide and to account for the heterogeneity of the soil composition at the global scale. Aerosol samples generated from soils were re-suspended in the chamber, where their LW extinction spectra (3–15 µm), size distribution, and mineralogical composition were measured. The generated aerosol exhibits a realistic size distribution and mineralogy, including both the sub- and super-micron fractions, and represents in typical atmospheric proportions the main LW-active minerals, such as clays, quartz, and calcite. The complex refractive index of the aerosol is obtained by an optical inversion based upon the measured extinction spectrum and size distribution. Results from the present study show that the imaginary LW refractive index (k) of dust varies greatly both in magnitude and spectral shape from sample to sample, reflecting the differences in particle composition. In the 3–15 µm spectral range, k is between ∼ 0.001 and 0.92. The strength of the dust absorption at ∼ 7 and 11.4 µm depends on the amount of calcite within the samples, while the absorption between 8 and 14 µm is determined by the relative abundance of quartz and clays. The imaginary part (k) is observed to vary both from region to region and for varying sources within the same region. Conversely, for the real part (n), which is in the range 0.84–1.94, values are observed to agree for all dust samples across most of the spectrum within the error bars. This implies that while a constant n can be probably assumed for dust from different sources, a varying k should be used both at the global and the regional scale. A linear relationship between the magnitude of the imaginary refractive index at 7.0, 9.2, and 11.4 µm and the mass concentration of calcite and quartz absorbing at these wavelengths was found. We suggest that this may lead to predictive rules to estimate the LW refractive index of dust in specific bands based on an assumed or predicted mineralogical composition, or conversely, to estimate the dust composition from measurements of the LW extinction at specific wavebands. Based on the results of the present study, we recommend that climate models and remote sensing instruments operating at infrared wavelengths, such as IASI (infrared atmospheric sounder interferometer), use regionally dependent refractive indices rather than generic values. Our observations also suggest that the refractive index of dust in the LW does not change as a result of the loss of coarse particles by gravitational settling, so that constant values of n and k could be assumed close to sources and following transport. The whole dataset of the dust complex refractive indices presented in this paper is made available to the scientific community in the Supplement.

scholarly journals Confidence Levels, Sensitivity, and the Role of Bathymetry in Coral Reef Remote Sensing

2020 ◽  
Vol 12 (3) ◽  
pp. 496 ◽  
Author(s):  
James A. Goodman ◽  
Mui Lay ◽  
Luis Ramirez ◽  
Susan L. Ustin ◽  
Paul J. Haverkamp
Keyword(s):  
Remote Sensing ◽  
Coral Reef ◽  
Coral Reefs ◽  
Water Depth ◽  
Data Availability ◽  
Sensor Technology ◽  
Internal Quality ◽  
Benthic Habitat ◽  
Model Output ◽  
Confidence Levels

Remote sensing is playing an increasingly important role in the monitoring and management of coastal regions, coral reefs, inland lakes, waterways, and other shallow aquatic environments. Ongoing advances in algorithm development, sensor technology, computing capabilities, and data availability are continuing to improve our ability to accurately derive information on water properties, water depth, benthic habitat composition, and ecosystem health. However, given the physical complexity and inherent variability of the aquatic environment, most of the remote sensing models used to address these challenges require localized input parameters to be effective and are thereby limited in geographic scope. Additionally, since the parameters in these models are interconnected, particularly with respect to bathymetry, errors in deriving one parameter can significantly impact the accuracy of other derived parameters and products. This study utilizes hyperspectral data acquired in Hawaii in 2000–2001 and 2017–2018 using NASA’s Classic Airborne Visible/Infrared Imaging Spectrometer to evaluate performance and sensitivity of a well-established semi-analytical inversion model used in the assessment of coral reefs. Analysis is performed at several modeled spatial resolutions to emulate characteristics of different feasible moderate resolution hyperspectral satellites, and data processing is approached with the objective of developing a generalized, scalable, automated workflow. Accuracy of derived water depth is evaluated using bathymetric lidar data, which serves to both validate model performance and underscore the importance of image quality on achieving optimal model output. Data are then used to perform a sensitivity analysis and develop confidence levels for model validity and accuracy. Analysis indicates that derived benthic reflectance is most sensitive to errors in bathymetry at shallower depths, yet remains significant at all depths. The confidence levels provide a first-order method for internal quality assessment to determine the physical extent of where and to what degree model output is considered valid. Consistent results were found across different study sites and different spatial resolutions, confirming the suitability of the model for deriving water depth in complex coral reef environments, and expanding our ability to achieve automated widespread mapping and monitoring of global coral reefs.

scholarly journals Abundance of Herbivorous Fish at Fish Apartment in Tangah Island Coastal Waters of Pariaman City, West Sumatera

2019 ◽  
Vol 6 (1) ◽  
pp. 97
Author(s):  
Suci Frimanozi ◽  
Indra Junaidi Zakaria ◽  
Jabang Nurdin
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Habitat Quality ◽  
Coastal Waters ◽  
Herbivorous Fish ◽  
Coral Recruitment ◽  
Visual Census ◽  
West Sumatra ◽  
And Control ◽  
Reef Condition

Herbivorous fish have an influence on habitat quality and a major factor in determining coral reef community. This herbivorous fish used as indicator of  monitoring refers to reef resilience since of its ability to retain and restore the coral reef condition after disturbance. The presence of herbivores is important in influencing succession of algae, it can reduce and control algae on coral reefs. It’s causes in the availability of space or substrate for corals to recruit. So the research conducted that aims to know the abundance of herbivorous fish in fish apartment as one indicator of monitoring based on endurance. This study had conducted after six months of fish apartment placed in the coastal waters of Tangah Island, Pariaman City, West Sumatra. Then, the observation had done every month for six months in July 2015 - January 2016 at the location of the fish apartment. Observation abundance of herbivorous fish had done by visual census method at fish apartment location. From the results of observations for six months found 10 species of herbivorous fish with total as many as 289 individuals. Zebrasoma scopas is a species with the most individuals than 97 individu. However, to see the effect of herbivorous fish on coral recruitment in fish apartment needs to do further research. Keywords: abundance, herbivorous fish, fish apartment

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 Accomplishments of the MUSICA project to provide accurate, long-term, global and high-resolution observations of tropospheric {H<sub>2</sub>O,<i>δ</i>D} pairs – a review

2016 ◽  
Vol 9 (7) ◽  
pp. 2845-2875 ◽  
Author(s):  
Matthias Schneider ◽  
Andreas Wiegele ◽  
Sabine Barthlott ◽  
Yenny González ◽  
Emanuel Christner ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Measurement Techniques ◽  
Remote Sensing Data ◽  
Global Scale ◽  
Horizontal Resolution ◽  
Atmospheric Composition ◽  
Remote Sensing Techniques ◽  
Middle Infrared

Abstract. In the lower/middle troposphere, {H2O,δD} pairs are good proxies for moisture pathways; however, their observation, in particular when using remote sensing techniques, is challenging. The project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) addresses this challenge by integrating the remote sensing with in situ measurement techniques. The aim is to retrieve calibrated tropospheric {H2O,δD} pairs from the middle infrared spectra measured from ground by FTIR (Fourier transform infrared) spectrometers of the NDACC (Network for the Detection of Atmospheric Composition Change) and the thermal nadir spectra measured by IASI (Infrared Atmospheric Sounding Interferometer) aboard the MetOp satellites. In this paper, we present the final MUSICA products, and discuss the characteristics and potential of the NDACC/FTIR and MetOp/IASI {H2O,δD} data pairs. First, we briefly resume the particularities of an {H2O,δD} pair retrieval. Second, we show that the remote sensing data of the final product version are absolutely calibrated with respect to H2O and δD in situ profile references measured in the subtropics, between 0 and 7 km. Third, we reveal that the {H2O,δD} pair distributions obtained from the different remote sensors are consistent and allow distinct lower/middle tropospheric moisture pathways to be identified in agreement with multi-year in situ references. Fourth, we document the possibilities of the NDACC/FTIR instruments for climatological studies (due to long-term monitoring) and of the MetOp/IASI sensors for observing diurnal signals on a quasi-global scale and with high horizontal resolution. Fifth, we discuss the risk of misinterpreting {H2O,δD} pair distributions due to incomplete processing of the remote sensing products.

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