79 research outputs found
Spatially integrative metrics reveal hidden vulnerability of microtidal salt marshes
No full textSalt marshes are valued for their ecosystem services, and their vulnerability is typically assessed through biotic and abiotic measurements at individual points on the landscape. However, lateral erosion can lead to rapid marsh loss as marshes build vertically. Marsh sediment budgets represent a spatially integrated measure of competing constructive and destructive forces: a sediment surplus may result in vertical growth and/or lateral expansion, while a sediment deficit may result in drowning and/or lateral contraction. Here we show that sediment budgets of eight microtidal marsh complexes consistently scale with areal unvegetated/vegetated marsh ratios (UVVR) suggesting these metrics are broadly applicable indicators of microtidal marsh vulnerability. All sites are exhibiting a sediment deficit, with half the sites having projected lifespans of less than 350 years at current rates of sea-level rise and sediment availability. These results demonstrate that open-water conversion and sediment deficits are holistic and sensitive indicators of salt marsh vulnerability
Closure to "Broad-Crested weirs with rectangular compound cross sections" by M. Gogus, Z. Defne, and V. Ozkandemir
No full textA series of laboratory experiments was performed in order to investigate the effects of width of the lower weir crest and step height of broad-crested weirs of rectangular compound cross section on the values of the discharge coefficient, the approach velocity coefficient, and the modular limit. For this purpose, nine different broad-crested weir models with rectangular compound cross sections and a model with a rectangular cross section were tested in a horizontal laboratory flume of 11.0 m length, 0.29 m width, and 0.70 m depth for a wide range of discharges. The compound cross sections were formed by a combination of three sets of step heights and three sets of lower weir crest widths. The sill-referenced heads at the approach channel and at the tailwater channel were measured in each experiment. The dependence of the discharge coefficient, approach velocity coefficient, and modular limit values on model parameters was investigated, and these quantities were compared with those of the broad-crested weir models with a rectangular cross section
Identifying salt marsh shorelines from remotely sensed elevation data and imagery
No full text© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Farris, A. S., Defne, Z., & Ganju, N. K. Identifying salt marsh shorelines from remotely sensed elevation data and imagery. Remote Sensing, 11(15), (2019): 1795, doi: 10.3390/rs11151795.Salt marshes are valuable ecosystems that are vulnerable to lateral erosion, submergence, and internal disintegration due to sea level rise, storms, and sediment deficits. Because many salt marshes are losing area in response to these factors, it is important to monitor their lateral extent at high resolution over multiple timescales. In this study we describe two methods to calculate the location of the salt marsh shoreline. The marsh edge from elevation data (MEED) method uses remotely sensed elevation data to calculate an objective proxy for the shoreline of a salt marsh. This proxy is the abrupt change in elevation that usually characterizes the seaward edge of a salt marsh, designated the “marsh scarp.” It is detected as the maximum slope along a cross-shore transect between mean high water and mean tide level. The method was tested using lidar topobathymetric and photogrammetric elevation data from Massachusetts, USA. The other method to calculate the salt marsh shoreline is the marsh edge by image processing (MEIP) method which finds the unvegetated/vegetated line. This method applies image classification techniques to multispectral imagery and elevation datasets for edge detection. The method was tested using aerial imagery and coastal elevation data from the Plum Island Estuary in Massachusetts, USA. Both methods calculate a line that closely follows the edge of vegetation seen in imagery. The two methods were compared to each other using high resolution unmanned aircraft systems (UAS) data, and to a heads-up digitized shoreline. The root-mean-square deviation was 0.6 meters between the two methods, and less than 0.43 meters from the digitized shoreline. The MEIP method was also applied to a lower resolution dataset to investigate the effect of horizontal resolution on the results. Both methods provide an accurate, efficient, and objective way to track salt marsh shorelines with spatially intensive data over large spatial scales, which is necessary to evaluate geomorphic change and wetland vulnerability.This project was supported by the U.S. Geological Survey (USGS) Coastal/Marine Natural Hazards and Resources Program as well as the Massachusetts O ce of Coastal Zone Management under interagency agreement 16ENMALQ006000
Buket Uzuner’in Uyumsuz Defne Kaman’ın Maceraları (su-toprak-hava) serisinde Türk mitolojisi unsurları
No full text06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Buket Uzuner'in kaleme aldığı Uyumsuz Defne Kaman'ın Maceraları serisine ait Su, Toprak, Hava romanları; Türk mitolojisini konu edinmeleri ve Türk mitolojisi ile ilgili birçok bilgiye yer vermeleri bakımından incelemeye değer görülmüştür. Bu çalışma ile amaçlanan, yapılacak inceleme sonucunda serinin romanlarında temas edilen Türk mitolojisine dair unsurları tespit etmektir. Çalışmanın kapsamı; Türk mitolojisi ve Uyumsuz Defne Kaman'ın Maceraları serisine ait Su, Toprak, Hava romanları olarak belirlenmiştir. Çalışma yürütülürken mitoloji ve Türk mitolojisi hakkında akademik kaynaklardan okuma, araştırma ve inceleme yapılmıştır. Türk mitolojisine ait unsurların ayrıntılı dökümü çıkarılmıştır. Yapılan inceleme sonucunda yazarın Türk mitolojisi konulu kaynakları taradığı ve Uyumsuz Defne Kaman'ın Maceraları serisini elde ettiği bilgiler üzerine kurguladığı tespit edilmiştir. Çalışmanın birinci bölümünde mit, mit-edebi eser ilişkisi, mitoloji, Türk mitolojisi ve Türk edebiyatında Türk mitolojisi gibi teze konu olan temel kavramlar hakkında bilgi verilmiştir. İkinci bölümünde romanların yazarı Buket Uzuner'in hayatı, edebi kişiliği ve eserleri ile ilgili açıklama yapılmıştır. Üçüncü bölüm incelenen romanların tanıtımına ayrılmış, romanların içeriğine ve özetine değinilmiştir. Dördüncü bölümde romanlarda yer alan Türk mitolojisine dair unsurların her biri müstakil olarak tespit edilmiştir. Tespit edilen unsurların Türk mitolojisine uygun olarak kullanılıp kullanılmadığı kaynaklardan yapılan alıntılarla belirlenmiştir. Sonuç bölümünde, çalışma boyunca yapılan tespitler hakkında değerlendirmeye yer verilmiştir. Kaynakça bölümünde ise tezin yazımında yararlanılan kaynaklar belirtilmiştir.Uyumsuz Defne Kaman'ın Maceraları, which include Su-Toprak-Hava novels, written by Buket Uzuner, has been deemed worthy of study in terms of having given a lot of information about Turkish mythology. The aim of this study is to determine the elements of the Turkish mythology that were contacted in the novels of the series. The scope of the study was determined as the novels of Turkish mythology and Su-Toprak-Hava novels which belongs to Uyumsuz Defne Kaman'ın Maceraları. While running the investigation research, analysing and reading were conducted from the academic sources about mythology and Turkish mythology. A detailed breakdown of the elements of Turkish mythology has been made. As a result of the study, it was found that the author scanned the sources on Turkish mythology and constructed the series on the information he gained. In the first part of the study, information has been given about the basic terms, which are the topics of the thesis, likemyth, myth-literary work, mythology, Turkish mythology and Turkish mythology in Turkish literature.In the second part, the life of the novelist Buket Uzuner and his literary personality and his works have been explained. The third part is devoted to the introduction of the novels reviewed and the content and summary of the novels are mentioned. In the fourth part, the elements of the Turkish mythology in the novels were identified as individual. Whether or not the identified elements were used in accordance with Turkish mythology is determined by quotations from sources.In the conclusion part, evaluations made during the study are evaluated. In the bibliography part, the sources used in writing the thesis are stated
Development and application of landsat-based wetland vegetation cover and unvegetated-vegetated marsh ratio (UVVR) for the conterminous United States
No full text© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ganju, N. K., Couvillion, B. R., Defne, Z., & Ackerman, K. Development and application of landsat-based wetland vegetation cover and unvegetated-vegetated marsh ratio (UVVR) for the conterminous United States. Estuaries and Coasts, (2022), https://doi.org/10.1007/s12237-022-01081-x.Effective management and restoration of salt marshes and other vegetated intertidal habitats require objective and spatially integrated metrics of geomorphic status and vulnerability. The unvegetated-vegetated marsh ratio (UVVR), a recently developed metric, can be used to establish present-day vegetative cover, identify stability thresholds, and quantify vulnerability to open-water conversion over a range of spatial scales. We developed a Landsat-based approach to quantify the within-pixel vegetated fraction and UVVR for coastal wetlands of the conterminous United States, at 30-m resolution for 2014–2018. Here we present the methodology used to generate the UVVR from spectral indices, along with calibration, validation, and spatial autocorrelation assessments. We then demonstrate multiple applications of the data across varying spatial scales: first, we aggregate the UVVR across individual states and estuaries to quantify total vegetated wetland area for the nation. On the state level, Louisiana and Florida account for over 50% of the nation’s total, while on the estuarine level, the Chesapeake Bay Estuary and selected Louisiana coastal areas each account for over 6% of the nation’s total vegetated wetland area. Second, we present cases where this dataset can be used to track wetland change (e.g., expansion due to restoration and loss due to stressors). Lastly, we propose a classification methodology that delineates areas vulnerable to open-water expansion based on the 5-year mean and standard deviation of the UVVR. Calculating the UVVR for the period-of-record back to 1985, as well as regular updating, will fill a critical gap for tracking national status of salt marshes and other vegetated habitats through time and space.This work was supported by the U.S. Geological Survey’s Coastal and Marine Hazards/Resources Program
Quantifying slopes as a driver of forest to marsh conversion using geospatial techniques: application to Chesapeake Bay coastal-plain, United States
No full text© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Molino, G. D., Defne, Z., Aretxabaleta, A. L., Ganju, N. K., & Carr, J. A. Quantifying slopes as a driver of forest to marsh conversion using geospatial techniques: application to Chesapeake Bay coastal-plain, United States. Frontiers in Environmental Science, 9, (2021): 616319, https://doi.org/10.3389/fenvs.2021.616319.Coastal salt marshes, which provide valuable ecosystem services such as flood mitigation and carbon sequestration, are threatened by rising sea level. In response, these ecosystems migrate landward, converting available upland into salt marsh. In the coastal-plain surrounding Chesapeake Bay, United States, conversion of coastal forest to salt marsh is well-documented and may offset salt marsh loss due to sea level rise, sediment deficits, and wave erosion. Land slope at the marsh-forest boundary is an important factor determining migration likelihood, however, the standard method of using field measurements to assess slope across the marsh-forest boundary is impractical on the scale of an estuary. Therefore, we developed a general slope quantification method that uses high resolution elevation data and a repurposed shoreline analysis tool to determine slope along the marsh-forest boundary for the entire Chesapeake Bay coastal-plain and find that less than 3% of transects have a slope value less than 1%; these low slope environments offer more favorable conditions for forest to marsh conversion. Then, we combine the bay-wide slope and elevation data with inundation modeling from Hurricane Isabel to determine likelihood of coastal forest conversion to salt marsh. This method can be applied to local and estuary-scale research to support management decisions regarding which upland forested areas are more critical to preserve as available space for marsh migration.Funding for this study was provided by the United States Geological Survey’s Coastal/Marine Hazards and Resources Program and Ecosystems Mission Area
Going global: The role of gatekeepers in the transnational reception of defne suman’s the silence of scheherazade
No full textGoing Global: The Role of Gatekeepers in the Transnational Reception of Defne Suman’s The Silence of ScheherazadeOn August 12, 2021, with hashtags, #historicalfiction, #translatedfiction, #greece, #turkey, #armenia, #levant #empire, #Scheherazade, Defne Suman announced the release of her English-language debut novel, The Silence of Scheherazade on social media. The novel centres on the tale of the burning of Smyrna in 1922, told through Levantine, Greek, Turkish and Armenian inhabitants of the city. Her gatekeepers, Head of Zeus Independent Publishing Company, the book’s translator Betsy Göksel and her literary agent Nermin Mollaoğlu were among the first ones to receive tribute for their hard work and support in the process. In the following months, Maureen Freely hosted the book’s launch in an online event, organized by Powell’s Books in Portland, Oregon. Succeeding interviews, book reading events and podcasts concentrated on the writer’s upbringing, other authors who influenced the style of the author, the translation process, the role of history in the book, as well as the motivation behind its title, which was different from its Turkish version, Emanet Zaman (2016).If World Literature is constituted by \"literary works that circulate beyond their culture of origin, either in translation or in their original language,\" as Damrosch (2003: 4) states, then, other actors who are involved in the work’s interaction with the world audience pave the way for its success in the global market, as William Marling claims in Gatekeepers: The Emergence of World Literature in the 1960s (2016:1). Taking its cue from the convergence of these insights, the paper focuses on the multi-layered gatekeeping process of Suman’s Scheherazade and explores the ways in which people and institutions have become integral components of its global dissemination.Works CitedDamrosch, David (2003) What is World Literature? Princeton and Oxford: Princeton University Press.Marling, William (2016) Gatekeepers: The Emergence of World Literature and the 1960s. New York: Oxford University Press
Estimating connectivity of hard clam (Mercenaria mercenaria) and eastern oyster (Crassostrea virginica) larvae in Barnegat Bay
No full text© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Goodwin, J. D., Munroe, D. M., Defne, Z., Ganju, N. K., & Vasslides, J. Estimating connectivity of hard clam (Mercenaria mercenaria) and eastern oyster (Crassostrea virginica) larvae in Barnegat Bay. Journal of Marine Science and Engineering, 7(6), (2019): 167, doi:10.3390/jmse7060167.Many marine organisms have a well-known adult sessile stage. Unfortunately, our lack of knowledge regarding their larval transient stage hinders our understanding of their basic ecology and connectivity. Larvae can have swimming behavior that influences their transport within the marine environment. Understanding the larval stage provides insight into population connectivity that can help strategically identify areas for restoration. Current techniques for understanding the larval stage include modeling that combines particle attributes (e.g., larval behavior) with physical processes of water movement to contribute to our understanding of connectivity trends. This study builds on those methods by using a previously developed retention clock matrix (RCM) to illustrate time dependent connectivity of two species of shellfish between areas and over a range of larval durations. The RCM was previously used on physical parameters but we expand the concept by applying it to biology. A new metric, difference RCM (DRCM), is introduced to quantify changes in connectivity under different scenarios. Broad spatial trends were similar for all behavior types with a general south to north progression of particles. The DRCMs illustrate differences between neutral particles and those with behavior in northern regions where stratification was higher, indicating that larval behavior influenced transport. Based on these findings, particle behavior led to small differences (north to south movement) in transport patterns in areas with higher salinity gradients (the northern part of the system) compared to neutral particles. Overall, the dominant direction for particle movement was from south to north, which at times was enhanced by winds from the south. Clam and oyster restoration in the southern portion of Barnegat Bay could serve as a larval supply for populations in the north. These model results show that coupled hydrodynamic and particle tracking models have implications for fisheries management and restoration activities.This work is supported by the Barnegat Bay Partnership EPA grants CE98212311, CE98212312.
We extend our deep thanks to anonymous reviewers and Lisa Lucas who provided thoughtful input that improved
the manuscript. We thank Matthew Kozak and Ian Mitchell for technical advice and Elizabeth North for LTRANS
guidance. Joe Caracapa and Jennifer Gius provided help running remote simulations. COAST model source code
is available at https://code.usgs.gov/coawstmodel/COAWST [50]. The hydrodynamic model outoput is available
at: http://geoport.whoi.edu/thredds/catalog/clay/usgs/users/zdefne/GRL/catalog.html [21] and particle tracking
model outputs are available from the corresponding author upon request
Are elevation and open-water conversion of salt marshes connected?
No full textAuthor Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 47(3), (2020): e2019GL086703, doi:10.1029/2019GL086703.Salt marsh assessments focus on vertical metrics such as accretion or lateral metrics such as open‐water conversion, without exploration of how the dimensions are related. We exploited a novel geospatial data set to explore how elevation is related to the unvegetated‐vegetated marsh ratio (UVVR), a lateral metric, across individual marsh “units” within four estuarine‐marsh systems. We find that elevation scales consistently with the UVVR across systems, with lower elevation units demonstrating more open‐water conversion and higher UVVRs. A normalized elevation‐UVVR relationship converges across systems near the system‐mean elevation and a UVVR of 0.1, a critical threshold identified by prior studies. This indicates that open‐water conversion becomes a dominant lateral instability process at a relatively conservative elevation threshold. We then integrate the UVVR and elevation to yield lifespan estimates, which demonstrate that higher elevation marshes are more resilient to internal deterioration, with an order‐of‐magnitude longer lifespan than predicted for lower elevation marshes.This study was supported by the USGS through the Coastal Marine Hazards/Resources Program, the National Park Service through the Natural Resource Preservation Program, and the U.S. Fish and Wildlife Service through the Science Support Partnership. Erika Lentz, Elizabeth Pendleton, Meagan Gonneea, Joel Carr, and two anonymous reviewers provided constructive advice on the study. S.F. was partly supported by US National Science Foundation award 1637630 (PIE LTER), 1832221 (VCR LTER). The geospatial data used in this study are published in the Coastal Wetlands Synthesis Products catalog on ScienceBase (https://www.sciencebase.gov/catalog/item/5b73325ee4b0f5d5787c5ff3)
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