Archipelago Research Articles

Spatiotemporal Changes and Utilization Intensity of the Zhoushan Archipelago Coastline over Four Decades

Coastal changes in China, notably in the Zhoushan Islands, have primarily been driven by coastal reclamation since the establishment of New China. This study conducted a comprehensive analysis of the Zhoushan Archipelago shoreline spanning four decades, employing remote sensing, aerial photographs, and shoreline data since 1984, along with GIS (Geographic Information System) technology. We assessed shoreline changes using the shoreline change index and shoreline artificialization index, as well as examined the influence of the Yangtze River’s suspended sediment and impoldering activities on Zhoushan’s shoreline. Furthermore, the correlation between local economic development and shoreline development was explored. The results revealed the following key findings: (1) From 1984 to 2018, the Zhoushan Archipelago shoreline decreased by 7.05 km. Temporally, the shoreline change index was −0.08%, with the most significant reduction occurring between 2008 and 2018. Spatially, differences among island groups were not pronounced. (2) The shoreline diversity index consistently increased, indicating greater diversity and complexity in shoreline use over the four decades. (3) The shoreline artificiality index steadily rose, particularly after 2000. It was highest in the south, followed by the center, and lowest in the north. (4) The intensity index of coastal land use continuously increased, with the southern island group having a higher index compared to the Zhoushan Islands. (5) The Yangtze River contributed significantly to sand inflow, influencing shoreline changes and beach shaping in Zhejiang. However, reclamation projects were identified as the primary and direct factor. (6) A positive correlation existed between Zhoushan City’s economic development and the intensity of coastal land use. This study emphasized the need for improving the control over reclamation projects and the better management of coastal protection and use. These measures could optimize resource allocation and establish a more scientific and rational coastal zone pattern.

Characteristics of divertor heat flux distribution with an island divertor configuration on the J-TEXT tokamak

On J-TEXT, the temporal evolution of heat flux distribution on the high-field side (HFS) divertor plate has been measured by an infrared (IR) camera during the plasma operation with an island divertor configuration. In experiments, the island divertor configuration is an edge magnetic island chain structure surrounded by stochastic layers, which can be induced by resonant magnetic perturbations (RMPs). The experimental results show that the heat flux distribution on the HFS target plate depends significantly on the edge magnetic topology. Furthermore, the impact of hydrogen fueling using supersonic molecular beam injection (SMBI) on the divertor heat flux distributions is studied on J-TEXT with an island divertor configuration. It has been observed that power detachment can be achieved when the radiation front approaches the last closed flux surface (LCFS) after each SMBI pulse. This result may provide a method of access for divertor detachment on a fusion device with a three-dimensional (3D) boundary magnetic structure.

Southeast Asia: A Colonial Oil Producer Fueling Its 21st Century Industrial Revolution With Gas

_ With natural gas destined to replace coal as its fuel of choice, Southeast Asia is unabashedly expanding its oil and gas industry to meet the skyrocketing energy demands of a booming population and unprecedented economic growth. Investments in regional hydrocarbon projects through 2029—particularly those in natural gas production—are forecast to exceed 4% compound annual growth rates with the spotlight on the region’s top two petroleum producers, Indonesia and Malaysia, according to the London-based Energy Council, a global network of senior energy finance executives. Norway’s Rystad Energy predicts that final investment decisions (FIDs) will be made between now and 2028 on $100 billion in new projects in the region, twice the $45 billion in FIDs taken from 2014 to 2023. These will include deepwater projects to develop new discoveries in Indonesia and Malaysia, and projects to create a global hub for carbon capture and storage (CCS) such as the one under study by Malaysian state-owned Petronas and Abu Dhabi’s ADNOC. The Malay Archipelago (also called the East Indies) is the world’s largest island group, and depending on the methodology of the geographer, it encompasses the 17,508 islands of Indonesia—literally the world’s largest country comprised of islands—and the approximately 7,000 islands of the Philippines. Indonesia and the Philippines in turn are among the 11 countries that constitute Southeast Asia after adding in Brunei, Burma (Myanmar), Cambodia, Timor-Leste, Laos, Malaysia, Singapore, Thailand, and Vietnam—all with widely diverse histories, cultures, and religions. But all with one thing in common: a colonial past forged by adventurers from across Europe who in the 19th century arrived on their shores to extract natural resources to feed the Industrial Revolution at home. In the case of the earliest industrial oil production in Dutch Indonesia and British Malaysia, those adventurers, over multiple generations, added Southeast Asia to the US and Azerbaijan as cornerstones of the modern oil industry while also breaking John D. Rockefeller’s monopoly of the Asian oil trade by building the first tanker to traverse the Suez Canal. Shortly after the turn of the 20th century two of these industrialists, one Dutch and one British, merged their companies to create what is today’s energy supermajor known as Shell. First Oil Launches Dutch East Indies Production Boom The history of oil production in Indonesia and Malaysia dates back over centuries with tales of a cottage industry of hand-dug wells to comb petroleum seeps for medicine, to waterproof boats, and to light torches and lamps. As the Industrial Revolution dawned, the Russian czar financed the world’s first mechanically drilled oil well in 1846 in Baku using cable-tool percussion drilling to carve out a 21-m-deep (69-ft) exploration well. In 1859, Edwin Drake added steam-engine power to a mechanical drill to produce the US’ first industrial class oil in Titusville, Pennsylvania.

Distinct management units for the Critically Endangered angelshark (Squatina squatina) revealed in the Canary Islands

AbstractThe angelshark, Squatina squatina, is listed as Critically Endangered on the IUCN Red List of Threatened Species, and remaining populations are highly fragmented throughout its historical distribution. The Canary Islands archipelago in the North East Atlantic has been identified as a uniquely large stronghold for the species. In the present study, we compared the population genetic structure of S. squatina across different islands of the Canary Island archipelago using both microsatellite and single nucleotide polymorphism (SNP) markers. Both markers revealed significant differentiation of angelsharks between islands in the archipelago, with three main genetic units at: (1) Tenerife, (2) Gran Canaria and (3) the island group consisting of La Graciosa, Lanzarote and Fuerteventura. Our results imply a connectivity barrier between some adjacent islands, most likely driven by abyssal depths, and varying geological history and formation of each island and oceanographic patterns (i.e. seasonal coastal upwellings off the African coast). Therefore, we suggest that in the Canary Islands, S. squatina populations should be managed locally, with conservation and research priorities designed and implemented specifically for each of the three genetic units.

A taxonomic re-evaluation of Pittosporum roimata Gemmill & S.N. Carter (Pittosporaceae, Apiales)

Pittosporum roimata Gemmill & S.N. Carter (Pittosporaceae, Apiales) was established in 2018 as an endemic species confined to the Poor Knights Islands group, off the eastern coastline of Northland Aotearoa / New Zealand. The new species was distinguished from P. cornifolium A. Cunn. on the basis of vegetative characters (leaf length, width, petiole length), floral characters (pedicel length, flower colour), and numbers of fruit per stem. The new species was also reported as differing from P. cornifolium by a single substitution within the nrITS cistron, with that data obtained from a paper that did not provide a phylogenetic interpretation of this result, nor specify whether the cultivated plants used were derived from seed obtained from multiple individuals or from cutting grown plants from a limited wild-sourced selection. In this paper the same morphological characters used to separate P. roimata are examined using a much wider sampling of P. cornifolium, and the specimens available for P. roimata. There are very slight differences in leaf width and length, petiole length, and pedicel length in Poor Knights Islands P. roimata specimens seen also in some collections from other northern Aotearoa / New Zealand offshore islands and some mainland stations. Flower colour is not a useful character as this is variable in P. roimata and P. cornifolium, as it is also in many other Aotearoa / New Zealand Pittosporum. On the basis of our morphological assessment we conclude that to maintain the segregation of P. roimata from P. cornifolium at the species rank is impractical, as there is a grading of characters between both species. As plants corresponding to P. roimata occur throughout the range of P. cornifolium, already a variable species, we suggest that, in line with other treatments of Aotearoa / New Zealand Pittosporum, it is better to reduce P. roimata into synonymy of P. cornifolium.

The Price of Prosperity: Annexation, Architecture, and the Late Modernist Development Frenzy in Hawai`i

ABSTRACT Shortly after the former U.S. Territory became the fiftieth state in 1959, the firm of Minoru Yamasaki and Associates (MYA) won a competition to design a new housing project in downtown Honolulu. Queen Emma Gardens, as it came to be known, was an attempt by the Detroit-based firm to assimilate U.S.-based late modernism to a tropical climate. Yamasaki, an avid golfer, enjoyed Hawaiian vacations and pursued commissions on O`ahu, chief among them apartment buildings and an office tower, along with unbuilt proposals for hotels and shopping centres. These opportunities came as a direct result of a westward movement among mainland U.S. citizens, the architect’s Japanese heritage, and a newfound obsession with the island chain, but such developments added to significant pressures facing local housing market, raising issues of race, identity, and the displacement of the urban poor in favor of sleek modernist housing deemed “appropriate” by city officials and funded by federal initiatives. The MYA-designed Hawaiian projects illustrate how one design firm’s formal and technical ambitions change over time, largely in response to shifting desires of clients, an evolving construction industry, and a growing tourist market, all of which come together in the development of a post-war itinerant architecture.

Larval dispersal and physical connectivity of Pheronema carpenteri populations in the Azores

The study of larval dispersal and connectivity between deep-sea populations is essential for the effective conservation and management of deep-sea environments and the design and implementation of Marine Protected Areas. Dense sponge aggregations, known as “sponge grounds”, are a key component of marine benthic ecosystems, by increasing the structural complexity of the sea floor and providing structure and habitat for many other species. These aggregations are characteristic of the Azores deep-sea environment. These sessile organisms rely primarily on larval dispersal for their reproduction. Connectivity between specific Pheronema carpenteri sponge aggregations in the Azores was studied using a 3-D biophysical dispersal model. Different biological trait scenarios were analyzed, considering spawning seasonality and pelagic larval duration. Model results indicate that regional circulation patterns drive larval dispersion, shaping population connectivity of P. carpenteri sponge aggregations in the Azores, particularly among aggregations in the Central Group of Azorean islands. Some areas present high retention rates, receiving larvae from several sponge aggregations while also being important larval source aggregations. In contrast, aggregations from the Eastern Group may be isolated from the others. Larval dispersal and connectivity patterns were analyzed concerning the current configuration of Marine Protected Areas (MPAs) in the Azores. The results underscored the importance of maintaining protection efforts in existing MPAs and identified stepping-stone locations and specific sites where additional measures could enhance species connectivity in the Azores.

Plio‐Pleistocene decline of mesic forest underpins diversification in a clade of Australian Panesthia cockroaches

AbstractThe progressive aridification of the Australian continent, and coincident decline of mesic forest, has been a powerful driver of allopatric and environmental speciation in native species. The relictual mesic forests of the eastern seaboard now harbour a diverse group of endemic fauna, including the wood‐feeding cockroaches of the genus Panesthia, which reached the continent via two separate invasions from Melanesia. The more recent of these colonization events gave rise to a group of five recognized species, occurring in mainland woodlands, sclerophylls and rainforests, as well as the forests and grasslands of the Lord Howe Island Group. Due to limited sampling in molecular studies and doubt regarding the standing taxonomy, there is little certainty about relationships among the species and poor understanding of the effects of ancient climatic change upon their evolution. We undertook a comprehensive phylogenetic analysis of the clade, using complete mitogenomes and nuclear ribosomal markers from nearly all known morphospecies and populations. Our time‐calibrated phylogenetic analyses reveal an additional six unrecognized, highly divergent lineages and suggest that these have arisen primarily through vicariance as rainforests fragmented during Plio‐Pleistocene glacial cycles (2–5 million years ago). Ancestral niche estimations also evidence a tropical rainforest origin for the group, followed by at least three niche transitions into drier forest, including one associated with the singular colonization of the Lord Howe Island Group. Finally, we find evidence of frequent, parallel wing reduction, in potential association with the contraction of forest habitats into small refugia. Our results reiterate the far‐reaching role of ancient aridification in driving speciation, niche expansion and morphological evolution in Australian fauna.

Community Archives as Agency: Intersectionality as a Framework to Document Chinese American Experiences in the United States

The U.S. has a history of anti-immigrant and anti-Asian. Asian Americans strive for agency in defining their identities. Intertwined with their history of exclusion is the absence and misrepresentation of Asian Americans in archives. In this dissertation, I first explore Chinese Americans’ understanding of their identity and its reflection of social inequality. Then, I investigate what they want to preserve to document their history to counter injustice. Lastly, I examine how Chinese Americans want to use community archives to enhance agency and fight against social injustice. I use interviews, workshops, and ethnographic methods to collect conversations with 17 participants who self-identify as Chinese descendants in the U.S. My dissertation finds that participants’ racial and ethnic identities shape their experiences of discrimination, pressure to assimilate to White society, a lack of belonging, and difficulty fitting into the Asian American Pacific Islander group. Furthermore, gender identity influences their experiences. For example, Chinese American women often face social expectations to prioritize family over themselves. Alongside unjust experiences, community members share lived experiences of resilience, joy, and achievements. My dissertation proposes intersectionality as a framework to understand the representational value of community archives. The intersectionality framework asserts, “it is not enough to simply ‘add race and stir’” (Smooth, 2013). My dissertation finds that participants challenge a thing-oriented approach that prioritizes preservation alone. Instead, they prefer an engagement-oriented approach that uses archives to transform counter-stories into agency, specifically into what Yosso (2005) calls cultural wealth, such as aspirational and social capital.

Neonatal mortality among disaggregated Asian American and Native Hawaiian/Pacific Islander populations.

We compared neonatal (<28 days) mortality rates (NMRs) across disaggregated Asian American and Native Hawaiian/Pacific Islander (AANHPI) groups using recent, national data. We used 2015-2019 cohort-linked birth-infant death records from the National Vital Statistics System. Our sample included 61,703 neonatal deaths among 18,709,743 births across all racial and ethnic groups. We compared unadjusted NMRs across disaggregated AANHPI groups, then compared NMRs adjusting for maternal sociodemographic, maternalclinical, and neonatal risk factors. Unadjusted NMRs differed by over 3-fold amongst disaggregated AANHPI groups. Native Hawaiian/Pacific Islander neonates in aggregate had the highest fully-adjusted odds of mortality (OR: 1.08 [95% CI: 0.89, 1.31]) compared to non-Hispanic White neonates. Filipino, Asian Indian, and Other Asian neonates experienced significant decreases in odds ratios after adjusting for neonatal risk factors. Aggregating AANHPI neonates masks large heterogeneity and undermines opportunities to provide targeted care to higher-risk groups.

1118. Dendrocacalia crepidifolia (Nakai) Nakai: Compositae

SummaryThe monotypic genus Dendrocacalia (Nakai) Nakai, with the species Dendrocacalia crepidifolia (Nakai) Nakai, a large shrub or small tree from the Bonin Islands or Ogasawara of Japan, is described and illustrated. Its ecology, pollination, dioecy and conservation are discussed; a detailed description is given. The species is now apparently restricted to the Haha‐jima island group, where the largest number of populations exist on Haji‐jima itself. Threats to its conservation are from two invasive trees, Ficus microcarpa and Psidium littorale.

Racial and Ethnic Disparities in Age-Specific All-Cause Mortality During the COVID-19 Pandemic

The end of the COVID-19 public health emergency (PHE) provides an opportunity to fully describe pandemic-associated racial and ethnic mortality disparities. Age-specific excess mortality differences have important downstream implications, especially in minoritized race and ethnicity populations. To characterize overall and age-specific all-cause excess mortality by race and ethnicity during the COVID-19 PHE and assess whether measured differences reflected changes from prepandemic disparities. This cross-sectional study analyzed data of all US residents and decedents during the COVID-19 PHE, aggregated by observed race and ethnicity (at time of death) and age. Statistical analysis was performed from March 2020 to May 2023. COVID-19 PHE period (March 2020 to May 2023). All-cause excess mortality (incident rates, observed-to-expected ratios) and all-cause mortality relative risks before and during the PHE. For the COVID-19 PHE period, data for 10 643 433 death certificates were available; mean (SD) decedent age was 72.7 (17.9) years; 944 318 (8.9%) were Hispanic; 78 973 (0.7%) were non-Hispanic American Indian or Alaska Native; 288 680 (2.7%) were non-Hispanic Asian, 1 374 228 (12.9%) were non-Hispanic Black or African American, 52 905 (0.5%) were non-Hispanic more than 1 race, 15 135 (0.1%) were non-Hispanic Native Hawaiian or Other Pacific Islander, and 7 877 996 (74.1%) were non-Hispanic White. More than 1.38 million all-cause excess deaths (observed-to-expected ratio, 1.15 [95% CI, 1.12-1.18]) occurred, corresponding to approximately 23 million years of potential life lost (YPLL) during the pandemic. For the total population (all ages), the racial and ethnic groups with the highest observed-to-expected all-cause mortality ratios were the American Indian or Alaska Native (1.34 [95% CI, 1.31-1.37]) and Hispanic (1.31 [95% CI, 1.27-1.34]) populations. However, higher ratios were observed in the US population aged 25 to 64 years (1.20 [95% CI, 1.18-1.22]), greatest among the American Indian or Alaska Native (1.45 [95% CI, 1.42-1.48]), Hispanic (1.40 [95% CI, 1.38-1.42]), and Native Hawaiian or Other Pacific Islander (1.39 [95% CI, 1.34-1.44]) groups. In the total population aged younger than 25 years, the Black population accounted for 51.1% of excess mortality, despite representing 13.8% of the population. Had the rate of excess mortality observed among the White population been observed among the total population, more than 252 000 (18.3%) fewer excess deaths and more than 5.2 million (22.3%) fewer YPLL would have occurred. In this cross-sectional study of the US population during the COVID-19 PHE, excess mortality occurred in all racial and ethnic groups, with disparities affecting several minoritized populations. The greatest relative increases occurred in populations aged 25 to 64 years. Documented differences deviated from prepandemic disparities.

Monitoring water infiltration in multiple layers of sandstone coal mining model with cracks using ERT

Abstract Many engineering disasters are related to water infiltration in cracks. Understanding the water infiltration in multi-layered sandstone cracks is crucial for monitoring and preventing water-related disasters in coal mines. In this study, we utilized the electrical resistivity tomography (ERT) technique to conduct a water infiltration monitoring experiment on the 2d-strata-model with cracks. The electrical resistivity ratio profiles with respect to the background unveiled the existence of three cracks. Model photography demonstrates two cracks of those cracks. The infiltration cracks exhibit distinct shape of a stripe or island chain electrical change ratio anomaly in the resistivity ratio profiles. Electrical resistivity change ratio is associated with the infiltration within the cracks. As the infiltration progresses, the resistivity change ratios relative to the background gradually decreases. This is evident in the reduction in ratios in the original stripe or island chain areas in the electrical resistivity ratio profiles. The diminished range expands, manifesting as an increase in the area of the original stripe or island chain. The infiltration patterns of the cracks can be categorized into three types: a stripe pattern, island chain and stripe pattern, and island chain pattern. The preferential flow paths along the crack are related to both the infiltration time and the volume of infiltration. In the early stages, there are clear preferential flow paths along cracks. However, as infiltration time and volume increase, these preferential flow paths along the cracks become less pronounced and may even disappear. The findings prove that ERT is suitable for monitoring water infiltration along the cracks in multi-layered sandstone in the early infiltration stage. Experiment results monitoring water infiltration cracks on the 2D-model show that the ERT and 2D-model are suitable for studying water infiltration along the cracks. This research can provide valuable reference for preventing engineering disaster.

Indigenous Identity Appropriation in Aotearoa New Zealand: The White Academics Who Claim to Be Indigenous Māori and the Māori Who Claim to Be Indigenous Whites

Unlike in North America, where several “race-shifters”, “Pretendians”, or “self-indigenizers” have been exposed over the last decade, Indigenous identity appropriation has not been publicly exposed or even widely discussed in Aotearoa New Zealand. This study is the first to identify and to describe the methods and motivations of four Pākehā (White) self-indigenizers who are currently working, or were trained, in Aotearoa New Zealand, outlining also the harms they have caused. In addition, this study examines another type of Indigenous identity appropriation taking place in Aotearoa New Zealand, involving a small group of central North Island Māori, whose primary spokesperson is Monica Matāmua. The group claim to be descended from white-skinned Hotu, who they purport had migrated to Aotearoa New Zealand in the 200s B.C., making them the alleged true Indigenous people instead of Māori. Each type of Indigenous identity appropriation provides a range of benefits to those who thereby claim Indigenous status, and this is in part due to the valorization of certain aspects of Indigeneity that occurred from ca. the 1960s to the 1980s. Indigenous identity appropriation has further been encouraged by the backlash against so-called “Māori privilege” that has gathered momentum since ca. the 1980s.

Using virtual fieldwork to support interprofessional and community-based learning: students from four faculties investigate life on a remote island in Japan

IntroductionThe Mishima Islands in Kagoshima Prefecture, Japan, are remote islands designated as medically underserved. Supporting the people living in such remote islands requires a multifaceted examination of the livelihoods of the residents, including their health, work, and living environment.MethodsStudents from the faculties of nursing, veterinary science, agriculture, and engineering participated in a 3-day virtual fieldwork session held synchronously from the campus of Kagoshima University and on a remote island in the Mishima Mura island group in Kagoshima Prefecture, Japan. Coursework and post-course surveys were analyzed to determine student engagement and learning. In particular, the analysis considered learning in relation to interprofessional learning and community-based learning.Results and discussionStudents expressed being able to conduct fieldwork online, collaborate with students from multiple faculties and graduate schools, and apply their expertise. These outcomes were reflected in the five-point Likert scale evaluation responses, highlighting a sense of accomplishment and satisfaction. Virtual fieldwork can contribute to student learning by introducing new concepts and allowing them to consider development issues in remote areas from multiple perspectives.

Taxonomy and Distribution of Benthic Foraminiferans in the Selected Group Islands of Gulf of Mannar Marine Biosphere Reserve

The present work deals with the taxonomy and distribution of benthic foraminifera from Gulf of Mannar Marine Biosphere Reserve (GoMBR), South east Coast of India during 2020 – 2023. Sediment samples were collected from Mandapam, Keezhakarai and Vembar group of Islands through standard methodology, A total of 36 species belonging to 20 genera, 16 families and 4 orders. A holistic approach regarding soil texture and physico-chemical properties of soil and water shed more light on the diversity and distribution of foraminifera in GoMBR.

O potencial da Guiné-Bissau para a economia azul: o caso das Ilhas Bijagós

According to the United Nations Economic Commission for Africa (UNECA, 2014)¹, the importance of ocean and coastal areas is fundamental for the six African states considered by the United Nations to be Small Island Developing States (SIDS): Guinea-Bissau, Cape Verde, São Tomé and Príncipe, Mauritius and the Seychelles.Guinea-Bissau is a country with a total coastline of 28,120 square kilometres and an estimated 80 islands located in its coastal waters, making it a key player in leading the transition to the blue economy on the African continent. Of the six African states considered as SIDS, Guinea-Bissau has the largest population, of around 1.6 million inhabitants, and the largest geographical area.The aim of this paper is to analyse the various sectors of the Blue Economy in Guinea-Bissau, developing a diagnosis of needs and a set of recommendations to promote the optimisation of maritime resources.Firstly, a geographical overview of Guinea-Bissau will be presented. Secondly, an argument will be developed to defend Guinea-Bissau's potential as one of Africa's main players in the area of the Blue Economy. This will be followed by a needs assessment of Guinea-Bissau's various Blue Economy sectors, namely: (1) the state of maritime transport; (2) tourism and Guinea-Bissau's natural capital; (3) fisheries; (4) fossil maritime energy; and (5) renewable energies.Following this diagnosis of the needs of Guinea-Bissau in general, the case of the Bijagós Archipelago, a group of islands in Guinea-Bissau considered a UNESCO World Biosphere Reserve protected area since 1996, will be analysed in greater detail.¹ UNECA, 2014.

Remote Impacts of Cyclonic Eddies on Productivity Around the Main Hawaiian Islands

AbstractThe Hawaiian Island chain lies on the southern limb of the oligotrophic North Pacific Subtropical Gyre, an area characterized by low productivity. In this region, productivity is controlled by several factors, including the island mass effect and mesoscale eddies generated by wind stress curl in the lee of the islands. This study identifies high‐chlorophyll events that occur periodically off the northern coasts of the Main Hawaiian Islands. These events are present in the satellite record and can be reproduced using a regional dynamical model. Model results indicate events are characterized by increases in total phytoplankton and total zooplankton, and a shift in phytoplankton size structure. We show these events are uniquely driven by the presence of cyclonic mesoscale eddies located downstream, on the opposite side of the island chain. While these eddies are known to impact productivity locally, we reveal that nutrients upwelled by these eddies can also be transported around the islands, counter to the mean background flow. These results demonstrate how leeward cyclonic eddies can have far‐reaching, remote impacts on productivity around the Hawaiian Islands.

Predicting Characteristic Length Scales of Barrier Island Segmentation in Microtidal Environments

AbstractSegmented barrier islands can be found in regions with small tidal ranges. In contrast to tidally dominated barriers, where inlet dynamics are thought to control island length scales, the controls on barrier island length scales in wave‐dominated environments have not been quantified. These microtidal barriers typically have a curved shoreline, suggesting the influence of wave‐driven alongshore sediment transport. Microtidal barriers are also typically hydrodynamically isolated from one another, as weak tidal flows limit interactions between adjoining barriers. To better understand the controls on and scales of barrier segmentation in the relative absence of tides, here we develop a theoretical framework to estimate the alongshore length scales at which a barrier will either breach or heal following a disturbance in the barrier morphology. The non‐dimensional framework compares the timescales of overwash (advective) and alongshore sediment transport (diffusive) processes along barrier island chains. We then apply this framework to modern barrier islands in the microtidal Gulf of Mexico using wave hindcast data and the lengths, widths, heights, and lagoon depths measured from remotely sensed geospatial data and topobathymetric data. We find that most of these barriers are currently longer than their critical length scale, often as a result of coastal restoration efforts. Our critical length scale analysis suggests that most of the Gulf of Mexico barriers are vulnerable to segmentation despite coastal restoration efforts intended to protect fisheries and the mainland coasts.

Analytical calculation of the kinetic q factor and resonant response of toroidally confined plasmas

Symmetry-breaking perturbations in axisymmetric toroidal plasma configurations have a drastic impact on particle, energy, and momentum transport in fusion devices, thereby affecting their confinement properties. The perturbative modes strongly affect particles with specific kinetic characteristics through resonant mode–particle interactions. In this work, we present an analytical calculation of the kinetic q factor, enabling the identification of particles with kinetic properties that meet the resonant conditions. This allows us to predict the locations and structures of the corresponding resonant island chains, as well as the existence of transport barriers in the particle phase space. The analytical results, derived for the case of a large aspect ratio configuration, are systematically compared to numerical simulations, and their domain of validity is thoroughly investigated and explained. Our findings demonstrate that calculating the kinetic q factor and its dependence on both particle and magnetic field characteristics provides a valuable tool for understanding and predicting the resonant plasma response to non-axisymmetric perturbations. Moreover, this approach can be semi-analytically applied to generic realistic experimental equilibria, offering a low-computational-cost method for scenario investigations under various multi-scale perturbative modes.