130 research outputs found

    NeMO-Net The Neural Multi-Modal Observation & Training Network for Global Coral Reef Assessment

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    We present NeMO-Net, the Srst open-source deep convolutional neural network (CNN) and interactive learning and training software aimed at assessing the present and past dynamics of coral reef ecosystems through habitat mapping into 10 biological and physical classes. Shallow marine systems, particularly coral reefs, are under significant pressures due to climate change, ocean acidification, and other anthropogenic pressures, leading to rapid, often devastating changes, in these fragile and diverse ecosystems. Historically, remote sensing of shallow marine habitats has been limited to meter-scale imagery due to the optical effects of ocean wave distortion, refraction, and optical attenuation. NeMO-Net combines 3D cm-scale distortion-free imagery captured using NASA FluidCam and Fluid lensing remote sensing technology with low resolution airborne and spaceborne datasets of varying spatial resolutions, spectral spaces, calibrations, and temporal cadence in a supercomputer-based machine learning framework. NeMO-Net augments and improves the benthic habitat classification accuracy of low-resolution datasets across large geographic ad temporal scales using high-resolution training data from FluidCam.NeMO-Net uses fully convolutional networks based upon ResNet and ReSneNet to perform semantic segmentation of remote sensing imagery of shallow marine systems captured by drones, aircraft, and satellites, including WorldView and Sentinel. Deep Laplacian Pyramid Super-Resolution Networks (LapSRN) alongside Domain Adversarial Neural Networks (DANNs) are used to reconstruct high resolution information from low resolution imagery, and to recognize domain-invariant features across datasets from multiple platforms to achieve high classification accuracies, overcoming inter-sensor spatial, spectral and temporal variations.Finally, we share our online active learning and citizen science platform, which allows users to provide interactive training data for NeMO-Net in 2D and 3D, integrated within a deep learning framework. We present results from the PaciSc Islands including Fiji, Guam and Peros Banhos 1 1 2 1 3 1 where 24-class classification accuracy exceeds 91%

    The mid-Holocene sea-level change in the Arabian Gulf

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    The mid-Holocene sea-level highstand is a well-known phenomenon in sea-level science, yet the knowledge on the highstand’s spatial and temporal distribution remains incomplete. Here we study the southwest coast of the Arabian-Persian Gulf where a mid-Holocene sea-level highstand and subsequent sea-level fall may have occurred due to the Earth crustal response to meltwater load. Sea-level indicators were established using standard facies analysis and error calculations, then constrained through glacio-isostatic adjustment (GIA) modelling and though procedures based on Gaussian Process and exponential decay analysis. This work allowed to identify the highstand at 1.6 ± 0.4 m occurring 6.7–6.0 ka, in excellent agreement with GIA model results. The subsequent shoreline migration followed the geophysical constraint by prograding in line with the sea-level fall until around 3 ka. Then, the strength of the external control weakened and internal processes, in particular sediment binding through microbial activity, started controlling the geometry of the accommodation space. </jats:p

    Tiger reefs: Self‐organized regular patterns in deep‐sea cold‐water coral reefs

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    Complexity theory predicts that self-organized, regularly patterned ecosystems store more biomass and are more resilient than spatially uniform systems. Self-organized ecosystems are well-known from the terrestrial realm, with “tiger bushes” being the archetypical example and mussel beds and tropical coral reefs the marine examples. We here identify regular spatial patterns in cold-water coral reefs (nicknamed “tiger reefs”) from video transects and argue that these are likely the result of self-organization. We used variograms and Lomb–Scargle analysis of seven annotated video transects to analyze spatial patterns in live coral and dead coral (i.e., skeletal remains) cover at the Logachev coral mound province (NE Atlantic Ocean) and found regular spatial patterns with length scales between 62 and 523 m in live and dead coral distribution along these transects that point to self-organization of cold-water coral reefs. Self-organization theory shows that self-organized ecosystems can withstand large environmental changes by adjusting their spatial configuration. We found indications that cold-water corals can similarly adjust their spatial configuration, possibly providing resilience in the face of climate change. Dead coral framework remains in the environment for extended periods of time, providing a template for spatial patterns that facilitates live coral recovery. The notion of regular spatial patterns in cold-water coral reefs is interesting for cold-water coral restoration, as transplantation will be more successful when it follows the patterns that are naturally present. This finding also underlines that anthropogenic effects such as ocean acidification and bottom trawling that destroy the dead coral template undermine cold-water coral resilience. Differences in the pattern periodicities of live and dead coral cover further present an interesting new angle to investigate past and present environmental conditions in cold-water coral reefs

    Tiger reefs: Self-organized regular patterns in deep-sea cold-water coral reefs

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    Abstract Complexity theory predicts that self-organized, regularly patterned ecosystems store more biomass and are more resilient than spatially uniform systems. Self-organized ecosystems are well-known from the terrestrial realm, with “tiger bushes” being the archetypical example and mussel beds and tropical coral reefs the marine examples. We here identify regular spatial patterns in cold-water coral reefs (nicknamed “tiger reefs”) from video transects and argue that these are likely the result of self-organization. We used variograms and Lomb–Scargle analysis of seven annotated video transects to analyze spatial patterns in live coral and dead coral (i.e., skeletal remains) cover at the Logachev coral mound province (NE Atlantic Ocean) and found regular spatial patterns with length scales between 62 and 523 m in live and dead coral distribution along these transects that point to self-organization of cold-water coral reefs. Self-organization theory shows that self-organized ecosystems can withstand large environmental changes by adjusting their spatial configuration. We found indications that cold-water corals can similarly adjust their spatial configuration, possibly providing resilience in the face of climate change. Dead coral framework remains in the environment for extended periods of time, providing a template for spatial patterns that facilitates live coral recovery. The notion of regular spatial patterns in cold-water coral reefs is interesting for cold-water coral restoration, as transplantation will be more successful when it follows the patterns that are naturally present. This finding also underlines that anthropogenic effects such as ocean acidification and bottom trawling that destroy the dead coral template undermine cold-water coral resilience. Differences in the pattern periodicities of live and dead coral cover further present an interesting new angle to investigate past and present environmental conditions in cold-water coral reefs

    Present Limits to Heat-Adaptability in Corals and Population-Level Responses to Climate Extremes

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    Climate change scenarios suggest an increase in tropical ocean temperature by 1–3°C by 2099, potentially killing many coral reefs. But Arabian/Persian Gulf corals already exist in this future thermal environment predicted for most tropical reefs and survived severe bleaching in 2010, one of the hottest years on record. Exposure to 33–35°C was on average twice as long as in non-bleaching years. Gulf corals bleached after exposure to temperatures above 34°C for a total of 8 weeks of which 3 weeks were above 35°C. This is more heat than any other corals can survive, providing an insight into the present limits of holobiont adaptation. We show that average temperatures as well as heat-waves in the Gulf have been increasing, that coral population levels will fluctuate strongly, and reef-building capability will be compromised. This, in combination with ocean acidification and significant local threats posed by rampant coastal development puts even these most heat-adapted corals at risk. WWF considers the Gulf ecoregion as “critically endangered”. We argue here that Gulf corals should be considered for assisted migration to the tropical Indo-Pacific. This would have the double benefit of avoiding local extinction of the world's most heat-adapted holobionts while at the same time introducing their genetic information to populations naĂŻve to such extremes, potentially assisting their survival. Thus, the heat-adaptation acquired by Gulf corals over 6 k, could benefit tropical Indo-Pacific corals who have <100 y until they will experience a similarly harsh climate. Population models suggest that the heat-adapted corals could become dominant on tropical reefs within ∌20 years

    Modeling the Potential Spread of the Recently Identified Non-Native Panther Grouper (Chromileptes altivelis)in the Atlantic Using a Cellular Automaton Approach

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    The Indo-pacific panther grouper (Chromileptes altiveli) is a predatory fish species and popular imported aquarium fish in the United States which has been recently documented residing in western Atlantic waters. To date, the most successful marine invasive species in the Atlantic is the lionfish (Pterois volitans/miles), which, as for the panther grouper, is assumed to have been introduced to the wild through aquarium releases. However, unlike lionfish, the panther grouper is not yet thought to have an established breeding population in the Atlantic. Using a proven modeling technique developed to track the lionfish invasion, presented is the first known estimation of the potential spread of panther grouper in the Atlantic. The employed cellular automaton-based computer model examines the life history of the subject species including fecundity, mortality, and reproductive potential and combines this with habitat preferences and physical oceanic parameters to forecast the distribution and periodicity of spread of this potential new invasive species. Simulations were examined for origination points within one degree of capture locations of panther grouper from the United States Geological Survey Nonindigenous Aquatic Species Database to eliminate introduction location bias, and two detailed case studies were scrutinized. The model indicates three primary locations where settlement is likely given the inputs and limits of the model; Jupiter Florida/Vero Beach, the Cape Hatteras Tropical Limit/Myrtle Beach South Carolina, and Florida Keys/Ten Thousand Islands locations. Of these locations, Jupiter Florida/Vero Beach has the highest settlement rate in the model and is indicated as the area in which the panther grouper is most likely to become established. This insight is valuable if attempts are to be made to halt this potential marine invasive specie

    Oceans across the solar system and the search for extraoceanic life: technologies for remote sensing and in situ exploration

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    Earth’s ocean comprises 99% of the habitable volume of our planet and contains the largest biomass and species diversity in the known universe. Perhaps unsurprisingly, recent advances in the search for life elsewhere in our solar system have increasingly pointed to potentially viable niches for life on other dynamic ocean worlds such as Titan, Europa, and Enceladus, among other moons of the outer gas giants. Indeed, the discovery of extraterrestrial life on these icy water bodies may motivate adopting an altogether new terminology and further non-anthropic perspective on the cosmos. Extraoceanic life, to coin a term, may well prove to be a designation more representative of the abundance and diversity of life in space. Exploration of such ocean worlds across the solar system will undoubtedly be enabled by technological developments in a range of sensing methodologies primarily developed for oceanography on Earth. As we have learned studying our home ocean, where less than 10% of the benthic surface has been optically imaged, the challenge is daunting, yet recent advances give hope. Here, we review some of the state-of-the-art techniques from oceanography and planetary science that may inform sensing of the biological and geophysical properties of ocean worlds, ranging from large-scale synoptic views afforded by active and passive remote sensing to in situ autonomous sampling and methods for detecting biosignatures

    Tiger reefs: Self‐organized regular patterns in deep‐sea cold‐water coral reefs

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    Complexity theory predicts that self‐organized, regularly patterned ecosystems store more biomass and are more resilient than spatially uniform systems. Self‐organized ecosystems are well‐known from the terrestrial realm, with “tiger bushes” being the archetypical example and mussel beds and tropical coral reefs the marine examples. We here identify regular spatial patterns in cold‐water coral reefs (nicknamed “tiger reefs”) from video transects and argue that these are likely the result of self‐organization. We used variograms and Lomb–Scargle analysis of seven annotated video transects to analyze spatial patterns in live coral and dead coral (i.e., skeletal remains) cover at the Logachev coral mound province (NE Atlantic Ocean) and found regular spatial patterns with length scales between 62 and 523 m in live and dead coral distribution along these transects that point to self‐organization of cold‐water coral reefs. Self‐organization theory shows that self‐organized ecosystems can withstand large environmental changes by adjusting their spatial configuration. We found indications that cold‐water corals can similarly adjust their spatial configuration, possibly providing resilience in the face of climate change. Dead coral framework remains in the environment for extended periods of time, providing a template for spatial patterns that facilitates live coral recovery. The notion of regular spatial patterns in cold‐water coral reefs is interesting for cold‐water coral restoration, as transplantation will be more successful when it follows the patterns that are naturally present. This finding also underlines that anthropogenic effects such as ocean acidification and bottom trawling that destroy the dead coral template undermine cold‐water coral resilience. Differences in the pattern periodicities of live and dead coral cover further present an interesting new angle to investigate past and present environmental conditions in cold‐water coral reefs

    Geomorphology and Reef Building in the SE Gulf

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    [Chapter Abstract] The Gulf, a subtropical epicontinental sea, is home to the northernmost coral reefs on the western boundary of the Indo-Pacific. The basin has an area of 250,000 sq. km and is shallow and semi-restricted, which combined with its high-latitude and the presence of mountainous plateaus and deserts nearby, make the Gulf’s climate the most extreme endured by reef-building corals anywhere in the world (Riegl et al. 2011, Chaps. 2, 7, and 9). Despite the hostile conditions, the Gulf is home to about 40 species of scleractinian and 31 species of alcyonacean corals, representing an impoverished but typical segment of that of the Indo-Pacific. The Gulf is unique in many respects, most notably in terms of its water chemistry, inclement climate (hot summers but also cold winters), and the hardiness of the corals that inhabit it. These factors conspire to prevent the development of spectacular reef edifices, like those that exist in the adjacent Red Sea, but nonetheless the expression of coral growth is as varied and interesting as the prevailing climate. The Gulf marks the separation between the stable Arabian foreland, atop which the U.A.E. sits, and the unstable Iranian fold belt. This positioning generates a specific geological set-up which conveys primary control on the geomorphology of the basin and in turn, the opportunities for reef development. Of particular note is the influence that salt tectonics play in the creation of offshore banks and islands, all of which support coral communities. Secondary and more recent modification has been exerted by the flooding of the Gulf during the last transgression, with the majority of the basin having lain sub-aerially exposed for considerable periods in the last 100,000 years. This complex and rich genesis brings the Gulf to a crossroads in the present day; we witness an unprecedented level of coastal development and modification fueled by rising economic prosperity on the back of vast hydrocarbon discoveries. Many areas of spectacular coral growth have been lost to construction, but some remain, for now. This chapter will detail the status of these ecosystems and the factors that have shaped them through time.https://nsuworks.nova.edu/occ_facbooks/1125/thumbnail.jp
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