Using high resolution multispectral imaging to map Pacific coral reefs in support of UNESCO's World Heritage Central Pacific project

2007 ◽  
Author(s):  
Daria Siciliano ◽  
Richard C. Olsen
Keyword(s):  
High Resolution ◽  
Coral Reefs ◽  
Multispectral Imaging ◽  
World Heritage ◽  
Central Pacific

Contrasting effects of the El Niño 2015–16 event on coral reefs from the central pacific coast of Mexico

2021 ◽  
Vol 42 (2) ◽  
Author(s):  
Héctor Nava ◽  
Norma López ◽  
Pedro Ramírez‐García ◽  
Elizabeth Garibay‐Valladolid
Keyword(s):  
Coral Reefs ◽  
El Niño ◽  
Pacific Coast ◽  
El Nino ◽  
Central Pacific

US Coral Reefs in the Line and Phoenix Islands, Central Pacific Ocean: Status, Threats and Significance

2008 ◽  
pp. 643-654 ◽  
Author(s):  
James Maragos ◽  
Alan M. Friedlander ◽  
Scott Godwin ◽  
Craig Musburger ◽  
Roy Tsuda ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Coral Reefs ◽  
Central Pacific ◽  
Central Pacific Ocean

scholarly journals High-resolution habitat and bathymetry maps for 65,000 sq. km of Earth’s remotest coral reefs

Coral Reefs ◽  
2019 ◽  
Vol 38 (3) ◽  
pp. 467-488 ◽  
Author(s):  
Sam J. Purkis ◽  
Arthur C. R. Gleason ◽  
Charlotte R. Purkis ◽  
Alexandra C. Dempsey ◽  
Philip G. Renaud ◽  
...  
Keyword(s):  
High Resolution ◽  
Coral Reefs

scholarly journals Mapping of complex structures: high resolution 3D renditions of vertical coral reefs

2017 ◽  
Author(s):  
K Robert ◽  
V A I Huvenne ◽  
D O B Jones ◽  
L Marsh ◽  
A Georgiopoulou
Keyword(s):  
High Resolution ◽  
Coral Reefs ◽  
Complex Structures

scholarly journals Thermal stress jeopardizes carbonate production of coral reefs across the western and central Pacific Ocean

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249008
Author(s):  
Robert van Woesik ◽  
Christopher William Cacciapaglia
Keyword(s):  
Thermal Stress ◽  
Pacific Ocean ◽  
Coral Reefs ◽  
Stress Gradient ◽  
Tropical Pacific ◽  
Tropical Pacific Ocean ◽  
Central Pacific ◽  
Carbonate Production ◽  
Building Capacity ◽  
Habitat Differences

Coral reefs protect islands, coastal areas, and their inhabitants from storm waves and provide essential goods and services to millions of people worldwide. Yet contemporary rates of ocean warming and local disturbances are jeopardizing the reef-building capacity of coral reefs to keep up with rapid rates of sea-level rise. This study compared the reef-building capacity of shallow-water habitats at 142 sites across a potential thermal-stress gradient in the tropical Pacific Ocean. We sought to determine the extent to which habitat differences and environmental variables potentially affect rates of net carbonate production. In general, outer-exposed reefs and lagoonal-patch reefs had higher rates of net carbonate production than nearshore reefs. The study found that thermal anomalies, particularly the intensity of thermal-stress events, play a significant role in reducing net carbonate production—evident as a diminishing trend of net carbonate production from the western to the central tropical Pacific Ocean. The results also showed a latent spatial effect along the same gradient, not explained by thermal stress, suggesting that reefs in the western tropical Pacific Ocean are potentially enhanced by the proximity of reefs in the Coral Triangle—an effect that diminishes with increasing distance and isolation.

High-resolution multispectral imaging system for improved color acquisition and reproduction

2000 ◽  
Author(s):  
Juerg Haefliger ◽  
R. Stein ◽  
Heinrich Walt ◽  
Peter F. Niederer
Keyword(s):  
High Resolution ◽  
Multispectral Imaging ◽  
Imaging System

scholarly journals An Improved Jitter Detection Method Based on Parallax Observation of Multispectral Sensors for Gaofen-1 02/03/04 Satellites

2018 ◽  
Vol 11 (1) ◽  
pp. 16 ◽  
Author(s):  
Ying Zhu ◽  
Mi Wang ◽  
Yufeng Cheng ◽  
Luxiao He ◽  
Lin Xue
Keyword(s):  
High Resolution ◽  
Multispectral Imaging ◽  
Detection Method ◽  
Negative Influence ◽  
Detection Accuracy ◽  
Comparison Results ◽  
Geometric Quality ◽  
Along Track ◽  
Internal Error ◽  
Multispectral Sensors

Gaofen-1 02/03/04 satellites, the first civilian high resolution optical operational constellation in China, have Earth observation capabilities with panchromatic/multispectral imaging at 2/8 m resolution. Satellite jitter, the fluctuation of satellite points, has a negative influence on the geometric quality of high-resolution optical satellite imagery. This paper presents an improved jitter detection method based on parallax observation of multispectral sensors for Gaofen-1 02/03/04 satellites, which can eliminate the effect of the relative internal error induced by lens distortion, and accurately estimate the parameters of satellite jitter. The relative internal error is estimated by polynomial modelling and removed from the original parallax image generated by pixel-to-pixel image matching between two bands of images. The accurate relative time-varying error and absolute distortion caused by satellite jitter could be estimated by using the sine function. Three datasets of multispectral images captured by Gaofen-1 02/03/04 satellites were used to conduct the experiments. The results show that the relative system errors in both the across- and along-track directions can be modelled with a quadratic polynomial, and satellite jitter with a frequency of 1.1–1.2 Hz in the across-track direction was detected for the first time. The amplitude of the jitter differed in the three datasets. The largest amplitude, from satellite 04, is 1.3 pixels. The smallest amplitude, from satellite 02, is 0.077 pixels. The reliability and accuracy of the detection results were verified by using two groups of band combinations and ortho-images with a 1 m resolution. The comparison results show that the detection accuracy is improved by approximately 30% using the proposed method.

Factors Affecting Coral Recruitment and Calcium Carbonate Accretion Rates on a Central Pacific Coral Reef

2021 ◽  
Author(s):  
◽  
Franziska Elmer
Keyword(s):  
Coral Reef ◽  
Calcium Carbonate ◽  
Coral Reefs ◽  
Benthic Community ◽  
Coral Cover ◽  
Coralline Algae ◽  
Benthic Organisms ◽  
Coral Recruitment ◽  
Central Pacific ◽  
Accretion Rates

<p>Coral recruitment and calcium carbonate (CaCO₃) accretion are fundamental processes that help maintain coral reefs. Many reefs worldwide have experienced degradation, including a decrease in coral cover and biodiversity. Successful coral recruitment helps degraded reefs to recover, while CaCO₃ accretion by early successional benthic organisms maintains the topographic complexity of a coral reef system. It is therefore important to understand the processes that affect coral recruitment and CaCO₃ accretion rates in order to understand how coral reefs recover from disturbances.  The aim of this thesis was to determine how biophysical forcing factors affect coral recruitment, calcification and bioerosion on a pristine coral reef. I used artificial settlement tiles to measure coral recruitment and CaCO₃ accretion at ten sites (four on the fore reef, four on the Western Reef Terrace and two at the Entrance Channel) at Palmyra Atoll. Fungia skeletons and pieces of dead coral rock were used to measure bioerosion rates, which were combined with the CaCO₃ accretion rates to obtain a net CaCO₃ budget of the reef substratum. Interactions between coral recruits and other benthic organisms on the settlement tiles were recorded to determine the settlement preferences and competitive strength of coral recruits. The settlement preference of Pocillopora damicornis for divots shaped like steephead and bumphead parrotfish bites marks was determined by adding P. damicornis larvae to a container with a settlement tile with the aforementioned divots.  I found that coral recruitment and CaCO₃ accretion are influenced by biophysical forcing factors. Most pocilloporids likely recruit close to their parents while the origin of poritid larvae is much more distant. Pocilloporid recruitment rates were also significantly correlated with the successional stage of the benthic community on the settlement tiles, especially the cover of biofilm and bryozoa. Biofilm and crustose coralline algae (CCA) were preferred as settlement substrata by coral larvae, however both pocilloporids and poritids settled on a large number of different benthic substrata. P. damicornis larvae showed a significant settlement preference for divots shaped like parrotfish bite marks over a flat settlement surface. Coral recruits were good competitors against encrusting algae but were often outcompeted by filamentous and upright algae. Settlement tiles were almost entirely colonised by benthic organisms within three to twelve months of deployment. The mass of CaCO₃ deposited onto the settlement tiles negatively correlated with herbivore grazing pressure on the benthic community. Bioerosion rates within pieces of coral (internal bioerosion) increased over time but overall bioerosion rates (internal and external) rarely exceeded CaCO₃ deposition by CCA.  My results show how variability in biophysical forcing factors leads to natural variation in coral recruitment and CaCO₃ accretion. This thesis highlights the importance of measuring herbivore grazing, CCA and turf algae cover to gain a better understanding of reef resilience. I conclude that models constructed for Caribbean reefs may not be suited to predict resilience in Pacific reefs and that within the Pacific, two different kinds of resilience models need to be constructed, one for human-inhabited coral reefs and one for uninhabited coral reefs.</p>

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