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

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

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

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

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 naïve 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

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

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

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

[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

Dynamics of Gulf Coral Communities: Observations and Models from the World’s Hottest Coral Sea

[Chapter Abstract] Coral reefs are adapted to a relatively narrow band of environmental optima and the harsh Gulf environment tests the physiological and ecological limits of reef corals. The environmental variability (minimal and maximal annual temperatures, salinity extremes, etc.; Chap. 2; Sheppard et al. 1992, 2010) are outside the range of typical tropical reefs. Regular summer temperatures are several degrees above the bleaching and mortality thresholds of some regions in the Great Barrier Reef and the Caribbean (Baker et al. 2008; Chap. 6). Yet, corals thrive in the Gulf. However, they have recently been exposed to severe temperature anomalies at a recurrence faster than in any other coral reef region (Riegl 2002, 2003; Sheppard and Loughland 2002; Riegl and Purkis 2009; Sheppard et al. 2010) and it appears that hot-anomalies are increasing in severity and frequency (Nasrallah et al. 2004). Thus, corals in the Gulf already exist in a thermal environment that is equal to, or even worse than, what is predicted (IPCC 2007) as occurring throughout the tropical oceans by 2099 and recognized as likely causing problems for coral reef persistence. Clearly, important lessons can be learned from Gulf corals about environmental extremes that corals can survive and, given the high frequency of disturbances, maybe even lessons in adaptability. Since the world is getting warmer and extremes are becoming more pronounced, the study of such extreme reef systems gains increased relevance.https://nsuworks.nova.edu/occ_facbooks/1128/thumbnail.jp

Coral Reefs of the Gulf Adaptation to Climatic Extremes

Coral Reefs of the Gulf: Adaptation to Climatic Extremes is a complete review and reference for scientists, engineers and students concerned with the geology, biology or engineering aspects of coral reefs in the Middle East. It provides for the first time a complete review of both the geology and biology of all extant coral areas in the Gulf, the water body between Iran and the Arabian Peninsula. In summer, this area is the hottest sea with abundant coral growth on earth and already today exhibits a temperature that is predicted to occur across the topical ocean in 2100. Thus, by studying the Gulf today, much can be learned about tomorrow’s world and the capability of coral reefs to adapt to climatic extremes. This volume provides the most authoritative and up-to-date review of the coral reefs in the Gulf. It can be used as a volume of general reference or as a textbook treating recent coral reefs. Written by local and international experts, the text is richly illustrated and will remain a standard reference for the region for decades to come. Contributions stretch from climatology through geology, biology, ecological modelling and fisheries science to practical conservation aspects. The book is useful for the technical expert and casual reader alike

Environmental Constraints for Reef Building in the Gulf

[Chapter Abstract] The Gulf is a peripheral basin of the Indian Ocean, at roughly 23°50′–29°52′ degrees northern latitude. It harbors extensive coral growth in one of the highest latitude locations in the world (Table 2.1). Due to its high-latitude position, its shallow nature, and its position within the great desert belt, the Gulf and its corals are exposed to extremes in temperature, salinity and other physical factors (Kinsman 1964a, b; Sheppard et al. 1992). But despite a seemingly hostile climate, corals endure and have been shown to exhibit remarkable resilience and vitality even if faced by some of the most extreme environmental conditions corals have to endure anywhere. This chapter will outline the most important physical constraints on reef building