Download or read book Terrigenous Sediment Dynamics in a Small Tropical Fringing reef Embayment written by and published by . This book was released on 2016 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic watershed disturbance by industry, agriculture, deforestation, roads, and urbanization alters the timing, composition, and mass of sediment loads to coral reefs, causing enhanced sediment stress on corals near the outlets of impacted watersheds (Syvitski et al., 2005; West and van Woesik, 2001). Few studies have developed an integrated understanding of sediment sources, transport processes, and deposition in small, reef-fringed embayments (Bartley et al., 2014; Draut et al., 2009; Wolanski et al., 2003) and many are outside the scope of local environmental managers in remote islands like at the study site, Tutuila, American Samoa. Ridge-to-Reef studies on sediment dynamics have three general components, which are reflected in the three chapter structure of this dissertation: watershed inputs, hydrodynamic circulation over the reef, and how they interact to govern spatiotemporal distribution of sediment accumulation on the reef. This dissertation provides an example of how a scientific, process-oriented Ridge to Reef study of sediment dynamics can answer critical scientific questions about the source, transport, and fate of sediment in the near-shore environment, and how answers to the scientific questions can support local coral management. Data on suspended sediment yield (SSY) from small, steep, tropical watersheds is limited, and assessments of sediment mitigation projects have been hindered by interannual climatic and sediment source variability. Chapter 1 used an event-wise approach to compare SSY from disturbed and undisturbed subwatersheds from storms of the same size, estimate total SSY to Faga'alu Bay, and estimate annual SSY to compare to other watersheds. It was unknown what the dominant sediment source was in Faga'alu watershed, and what potential management solutions were available. The sediment budget developed in the first chapter of this dissertation showed the quarry was a significant source, compared to natural background, and so local managers focused on reducing sediment discharge from the quarry. Continued monitoring presented in the third dissertation chapter showed SSY to the Bay was significantly reduced following sediment mitigation at the quarry. The fate of suspended sediment once it enters the marine environment is difficult to predict, but is strongly controlled by hydrodynamic conditions and circulation patterns. Computer models of hydrodynamic circulation require detailed forcing data, bathymetric data, and computer resources that are often unavailable to local managers. Chapter 2 of the dissertation used a simple approach combining Lagrangian GPS-logging drifters and Eulerian acoustic current profilers to determine dominant water circulation patterns under the most common conditions that characterize forcing in the Bay: calm, high onshore winds, and high waves. Measuring sediment accumulation on the reef is a contested area of research and the most common method, using tube traps, has some weaknesses. Others argue flat surfaces should be used to show net sediment accumulation. Chapter 3 presents results from both tubular sediment traps and flat-surfaced sediment pods to show gross vs net monthly sediment accumulation over one year. While many studies deploy traps haphazardly, or just below stream outlets, here sediment traps were arranged to observe spatial patterns between the north and south sections of the reef, as a result of prevailing currents and distance from the stream outlet. Integrating SSY and water circulation from Chapters 1 and 2 with observations of sediment accumulation in Chapter 3 showed that the predominant water circulation patterns deflect the storm-supplied terrigenous sediment from the stream over the northern reef where it caused enhanced sediment stress on corals. Temporal patterns of sedimentation were complex, and only the site nearest the stream outlet correlated with monthly SSY from the watershed, whereas nearly all sites showed increased carbonate sedimentation with increased wave energy. Sediment accumulated in traps and on sediment pods was mostly similar to surrounding benthic sediment, and correlated with wave energy, showing most sediment transport over the reef was from wind and wave-forced resuspension of carbonate sediment.
Download or read book Population Dynamics of the Reef Crisis written by and published by Academic Press. This book was released on 2020-11-13 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: Population Dynamics of the Reef Crisis, Volume 87 in the Advances in Marine Biology series, updates on many topics that will appeal to postgraduates and researchers in marine biology, fisheries science, ecology, zoology and biological oceanography. Chapters in this new release cover SCTL disease and coral population dynamics in S-Florida, Spatial dynamics of juvenile corals in the Persian/Arabian Gulf, Surprising stability in sea urchin populations following shifts to algal dominance on heavily bleached reefs, Biophysical model of population connectivity in the Persian Gulf, Population dynamics of 20-year decline in clownfish anemones on coral reefs at Eilat, northern Red Sea, and much more. - Reviews articles on the latest advances in marine biology - Authored by leading figures in their respective fields of study - Presents materials that are widely used by managers, students and academic professionals in the marine sciences
Download or read book Factors Affecting Terrigenous Sedimentation in Coastal Bays with Coral Reefs written by Whitney Taylor Sears and published by . This book was released on 2015 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the Caribbean, sedimentation has been identified as a serious threat to coral reef communities. Although land-based sediment delivery to coastal waters harboring coral reefs occurs under natural conditions, human activities in the watersheds above reefs increases the erosion and delivery of terrigenous sediment to the reefs. Delivery of terrigenous sediment into marine areas below developed watersheds affects sedimentation rates, alters the composition and texture of sediments that are suspended in the water column, and/or sediments that are deposited on the sea floor and on corals. St. John, U.S. Virgin Islands is an ideal location to study the effects of rainfall and human development on sedimentation on coral reefs. From a management perspective, there is a need on St. John for studies that examine how watershed development and watershed restoration activities affect marine sedimentation. The outcomes of this study have shown that sediment traps are an effective way to monitor general temporal and spatial patterns in terrigenous sedimentation. This study is the first marine sediment trap study to capture the natural variability in storms, rainfall, and wave activity over a study period longer than two years that also monitored distinct near shore and offshore areas below both developed and minimally developed watersheds simultaneously. Monitoring simultaneously across distinct areas over a long, 5-year study period made it possible to examine the relationship between terrigenous sedimentation, rainfall and wave activity statistically, and identify areas most likely to be subjected to the greatest sediment-related coral stress. The results of this study have generated potentially useful data related to watershed land management in tropical, coastal areas and will help inform future studies that will assess the effect of watershed restoration efforts on terrigenous sediment delivery to marine areas harboring coral reefs.
Download or read book Circulation Residence Time and Retention in a Tropical Coral Reef written by Liv Muir Meltzner Herdman and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We perform a study of residence time and circulation on the tropical fringing reef on the north shore of Moorea, French Polynesia. This study was motivated by the dependence of many important biological factors on residence time, notably, phytoplankton biomass, nutrient availability and larval recruitment. Three important features that are common to fringing reef systems were identified as important to residence time: 1) the strength of wave-driven flow 2) the dynamics of a jet exiting the reef pass and 3) thermal buoyancy-driven exchange. Through field observations we determine that wave-driven flow is responsible for the majority of the volume flow through the system. Our analysis of the field observations shows that water exiting through the reef passes was often re-entrained by the wave driven flow; this provides an important retention mechanism for reef water. The amount of water retained by a wide reef pass was investigated with field measurements and a simplified numerical model of the field site. We find that alongshore flow, jet strength, jet buoyancy and jet to reef area ratios are all important factors influencing retention. In normal winter field conditions, the amount of water re-entrained ranged from 20- 50 percent of exiting water. Additionally, we find that the exchange in the back bay of the system is primarily determined by variations in depth that create horizontal thermal and therefore buoyancy gradients. The horizontal buoyancy gradients are an important mechanism for exchange in parts of the reef less affected by the wave-driven circulation. The difference in heating between the reef and the ocean also maintains a stratified exchange flow in the pass; the dynamics that determine the interface and mixing at the jet are controlled by this thermal stratification.
Download or read book A Tale of Two Reefs written by Samantha Allysa Maticka and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Coral reefs are some of the most biodiverse ecosystems on the planet and serve as natural breakwaters that protect our coasts from storm impacts. Due to their sessile nature, corals' ability to thrive is at the mercy of their physical environment; flow rates, temperature, and flushing of the water that surround them determine their health. In the past 6 thousand years with relatively stable sea level, coral have adapted to the changing ocean, but anthropogenic influence has led to oceanic changes at accelerated rates, which raises the question `how will reefs fair with the changing climate?' To answer this question, we first need to understand the physics that drive flow in reef systems. We can then apply this fundamental understanding to models that can forecast their future state. This dissertation reports field experiments that were conducted at two different reefs, in both cases with the goal of understanding their fundamental flow dynamics. These were: (1) a fringing reef in Ofu, American Samoa that is notable for being more hydrodynamically rough than are most fringing reefs that have been previously studied and are home to heat resilient corals; and (2) Scott Reef, a reef atoll off the coast of Australia, where previous work has observed corals with remarkable ability to recover from severe bleaching. Ultimately, the Ofu project sought to understand how the high hydrodynamic roughness affected the flow dynamics in a fringing reef lagoon system. The work included: (1) lagoon-scale circulation dynamics; (2) wave-driven flow dynamics on the reef flat; and (3) wave transformations across shore. We observed lagoon-wide wave setup that led to: rip-currents and undertow across the reef flat; along-reef flow on the reef flat; and, a momentum balance on the reef flat that differed from what is commonly observed on reef flats in reef-lagoon systems. The momentum balance on the flat was between an offshore pressure gradient force, an onshore radiation stress gradient, and a depth varying shear stress that led to development of an undertow. Additional observations included: baroclinic flow in the channel generated by heating of the shallow lagoon that led to a cross-shore temperature gradient; a transfer of wave energy from high to low frequencies; examination of the mechanisms leading to energy dissipation of short waves at cross-shore stations; and, identification of a divergent circulation pattern that creates `pools' in the lagoon. These pools were initially observed by biologists to be regions in the lagoon that contain genetically distinct coral ecosystems. The project at South Scott reef was designed to understand the thermodynamics on the atoll rim. Additionally, and unexpectedly, flows across the rim were found to be due to amplification in the lagoon of the local tide. On the shallow rim of the atoll, we found the heat budget to be a balance of advective heating, surface atmospheric heating, and local heating (unsteadiness). The momentum balance was between bottom friction and a pressure gradient force that was set by the difference in free-surface elevation due to tidal amplification in the lagoon. Pulses of cold water were also observed to travel down the forereef slope (oceanside), with a generation mechanism linked to the shallow rim water cooling at night and being pushed off by tidal flow. Lastly, the lagoon amplification generated higher high tides and lower low tides in the lagoon that led to a reversed tidal flow on the rim, where the tide flooded outward (toward ocean) and ebbed inward (toward lagoon). The amplification was associated with the wide deep sill opening at the north end of South Scott reef that allowed tidal flow to enter without attenuation, which is often observed in reef atolls. The amplification in the free-surface was associated with the deceleration of tidal flow as it approached the atoll rim.
Download or read book The Effects of Coral Morphology and Rugosity on Small scale Reef Sediment Dynamics written by Samantha W. Page and published by . This book was released on 2011 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Fringing Reefs of Magnetic Island written by and published by . This book was released on 1992 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coral Reefs of the Eastern Tropical Pacific written by Peter W. Glynn and published by Springer. This book was released on 2016-08-12 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book documents and examines the state of health of coral reefs in the eastern tropical Pacific region. It touches on the occurrence of coral reefs in the waters of surrounding countries, and it explores their biogeography, biodiversity and condition relative to the El Niño southern oscillation and human impacts. Additionally contained within is a field that presents information on many of the species presented in the preceding chapters.
Download or read book Biogeochemical Dynamics at Major River Coastal Interfaces written by Thomas Bianchi and published by Cambridge University Press. This book was released on 2014 with total page 673 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive, state-of-the-art synthesis of biogeochemical dynamics and the impact of human alterations at major river-coastal interfaces for advanced students and researchers.
Download or read book Oceanographic Processes of Coral Reefs written by Eric Wolanski and published by CRC Press. This book was released on 2000-12-20 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: Demonstrating the relevance and need of science in planning the future of the Great Barrier Reef and coral reefs worldwide, Oceanographic Processes of Coral Reefs: Physical and Biological Links in the Great Barrier Reef emphasizes multi-disciplinary processes - physical and biological links - that have emerged as the dominant forces shaping and con
Download or read book Dredging and Port Construction Around Coral Reefs written by and published by PIANC. This book was released on 2010 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book World Atlas of Seagrasses written by Frederick T. Short and published by Univ of California Press. This book was released on 2003 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seagrasses are a vital and widespread but often overlooked coastal marine habitat. This volume provides a global survey of their distribution and conservation status.
Download or read book Catchments and Corals written by Miles Jonathan Furnas and published by . This book was released on 2003 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text provides the first comprehensive description of the state of the Great Barrier Reef catchment, modern levels of runoff to the reef and the influence of runoff on coastal reef ecosystems.
Download or read book Encyclopedia of Modern Coral Reefs written by David Hopley and published by Springer Science & Business Media. This book was released on 2010-11-26 with total page 1226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coral reefs are the largest landforms built by plants and animals. Their study therefore incorporates a wide range of disciplines. This encyclopedia approaches coral reefs from an earth science perspective, concentrating especially on modern reefs. Currently coral reefs are under high stress, most prominently from climate change with changes to water temperature, sea level and ocean acidification particularly damaging. Modern reefs have evolved through the massive environmental changes of the Quaternary with long periods of exposure during glacially lowered sea level periods and short periods of interglacial growth. The entries in this encyclopedia condense the large amount of work carried out since Charles Darwin first attempted to understand reef evolution. Leading authorities from many countries have contributed to the entries covering areas of geology, geography and ecology, providing comprehensive access to the most up-to-date research on the structure, form and processes operating on Quaternary coral reefs.
Download or read book The Spanish Coastal Systems written by Juan A. Morales and published by Springer. This book was released on 2018-09-03 with total page 809 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents the state of art of the geologic knowledge about the Spanish coast obtained through scientific research in the last 30 years.From a general point of view, coasts are the most quickly changing systems of the Earth. This is critical, since many human resources, such as the main part of economic and social activities, are located in the coastal areas. Especially in the case of Spain these coasts include cities, wide industrial areas (including harbor complexes), important ecologic systems, and our main economic resource: tourism. Understanding the dynamic functioning of each element of this coast is vital for correct future coastal management, so as to solve problems derived from bad plans developed in the last decades of the twentieth century. This is a valuable text for advanced graduate students and coastal researchers, which connects the specific dynamic functioning of the main Spanish coastal environments and their relationships with human activities.
Download or read book The Ocean and Cryosphere in a Changing Climate written by Intergovernmental Panel on Climate Change (IPCC) and published by Cambridge University Press. This book was released on 2022-04-30 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.
Download or read book Encyclopedia of Coastal Science written by M. Schwartz and published by Springer Science & Business Media. This book was released on 2006-11-08 with total page 1243 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new Encyclopedia of Coastal Science stands as the latest authoritative source in the field of coastal studies, making it the standard reference work for specialists and the interested lay person. Unique in its interdisciplinary approach. This Encyclopedia features contributions by 245 well-known international specialists in their respective fields and is abundantly illustrated with line-drawings and photographs. Not only does this volume offer an extensive number of entries, it also includes various appendices, an illustrated glossary of coastal morphology and extensive bibliographic listings.
