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Rapid shoreline changes at Stromboli Island have been documented from maps and aerial photographs dating from 1938 to 2003. Shorelines digitized from aerial photographs, taken at decadal intervals on average, show that while cliffed tracts were relatively stable, beaches on the N and NE side of the island experienced alternating accretion and erosional stages linked, respectively, with the contemporary eruptions and with sediment redistribution and/or the washing out and loss of sediment to deeper waters. Sciara del Fuoco, on the central-western side of the island, is where most of the volcanic products have accumulated during the practically continuous activity of the last two thousands years; from there, sands and gravel drift alongshore and are added to beaches on the N and NE side of the island. A simple model of clockwise longshore drift along the W, N, and NE coasts of the island is presented, taking into account the influences of manmade structures on shoreline changes.
Five asymmetrical, discontinuous, stratigraphically successive Pleistocene reef tracts rim the windward platform margin off the Florida Keys. Built of large head corals, the reefs are imposing in relief (∼30 m high by 1 km wide), as measured from seismic profiles. Well dated to marine oxygen isotope substages 5c, 5b, and 5a, corals at depth are inferred to date to the Stage 6/5 transition. The size of these reefs attests to late Pleistocene conditions that repeatedly induced vigorous and sustained coral growth. In contrast, the setting today, linked to Florida Bay and the Gulf of Mexico, is generally deemed marginal for reef accretion. Incursion onto the reef tract of waters that contain seasonally inconsistent temperature, salinity, turbidity, and nutrient content impedes coral growth.
Fluctuating sea level and consequent settings controlled deposition. The primary dynamic was position of eustatic zeniths relative to regional topographic elevations. Sea level during the past 150 ka reached a maximum of ∼10.6 m higher than at present ∼125 ka, which gave rise to an inland coral reef (Key Largo Limestone) and ooid complex (Miami Limestone) during isotope substage 5e. These formations now form the Florida Keys and a bedrock ridge beneath The Quicksands (Gulf of Mexico). High-precision radiometric ages and depths of dated corals indicate subsequent apices remained ∼15 to 9 m, respectively, below present sea level. Those peaks provided accommodation space sufficient for vertical reef growth yet exposed a broad landmass landward of the reefs for >100 ka. With time, space, lack of bay waters, and protection from the Gulf of Mexico, corals thrived in clear oceanic waters of the Gulf Stream, the only waters to reach them.
Each year, approximately 4 × 108 tons of sediment from multiple river sources is discharged to the Gulf of Papua. This large supply enters a system where physical energetics vary seasonally and accumulation of mud and sand occurs on the inner shelf. Sediment supplied by the largest of these fluvial sources, the Fly River, is advected northeastward by the prevailing currents, where it joins with sediment supplied from other rivers. Three sedimentary deposits are identified along the 20-meter isobath: (1) slowly accumulating (∼0.6 cm y−1) massive sandy mud in the west; (2) interbedded mud and sand with higher accumulation rates (1.9–2.7 cm y−1) in the central region; and (3) slowly accumulating (∼0.7 cm y−1) bioturbated muds in the east.
Trends in the preserved strata reflect the interaction of fluvial, tidal, and wave processes. In the tidally energetic western region, massive sandy units dominate, whereas interbeds of mud and sand are observed in the central region. The interbeds (centimeters thick) are hypothesized to be related to seasonal changes in the hydrodynamics of the Gulf: deposition and erosion of sediment associated with changes between monsoon and trade-wind conditions. On finer scales (millimeters), the sedimentary structures observed in the Gulf are typical of those found in tide-dominated deltaic settings. Bioturbated sedimentary structures characterize the eastern Gulf, as a result of slow accumulation by fine material and less energetic physical processes.
Several important relationships are recognized for the Gulf of Papua: (1) the large supply of fine-grained sediment allows it to accumulate at significant rates on the inner shelf; (2) quiescent monsoon conditions probably aid sediment retention on the inner shelf; and (3) coalescence of supply from multiple river sources causes maximum accumulation rates to occur in the central Gulf of Papua.
Coastal land loss in the Mississippi River delta region, related to degradation of wetlands and erosion of barrier islands, contributes to loss of valuable habitat, endangerment of infrastructure and socioeconomic systems, and coastal flooding hazards. Restoration of these ecosystems is thus a primary activity that requires large volumes of sand to rebuild beach–dune systems and restore wetland habitats. Sand sources have traditionally been sought offshore in the marine environment, but there are problems associated with setbacks from oil and gas infrastructure, presence of muddy overburden, and limited reserves of beach-quality sediments. Fluvial sand sources in channel and point-bar deposits become an attractive alternative for barrier island restoration because of large volumes of relict deposits and because active sand waves are renewable. Results of preliminary geophysical and geotechnical investigations in the lower Mississippi River (south of New Orleans) along a 32-km stretch of the river indicate the presence of at least 23 million cubic meters of usable sediments in seven potential borrow sites. Caveats to assessment and exploitation of river sands include interpretation of vibracores and seismic reflection profiles that include evidence of lateral translation-type bank failures along bendways, lateral slumps, and postdepositional disturbance of strata above −30 m. Reliable extraction of good quality sediment should occur down current from bendways.
Many researchers assume a proportional relationship among the atmospheric CO2 concentration, temperature, and sea level. Thus, the rate of sea-level rise should increase in concert with the documented exponential increase in CO2. Although sea surface temperature has increased in places over the past century and short-term sea level rose abruptly during the 1990s, it is difficult to demonstrate a proportional relationship using existing geologic or historic records. Tide gauge records in the United States cover too short a time interval to verify acceleration in the rate of sea-level rise, although multicentury tide gauge and staff records from the Netherlands and Sweden suggest a mid-19th-century acceleration in sea-level rise. Reconstructions of sea-level changes for the past 1000 years derived using benthic foraminifer data from salt marshes along the East Coast of the United States suggest an increased rate of relative sea-level rise beginning in the 1600s. Geologic records of relative sea-level rise for the past 6000 years are available for several sites along the US East Coast from 14C-dated basal peat below salt marshes and estuarine sediments. When these three scales of sea-level variation are integrated, adjusted for postglacial isostatic movement, and replotted, the range of variation in sea level suggested by basal peat ages is within ±1 meter of the long-term trend. The reconstruction from Long Island Sound data shows a linear rise in sea level beginning in the mid-1600s at a rate consistent with the historic record of mean high water. Long-term tide gauge records from Europe and North America show similar trends since the mid–19th century. There is no clear proportional exponential increase in the rate of sea-level rise. If proportionality exists among sea level, atmospheric CO2, and temperature, there may be a significant time lag before an anthropogenic increase in the rate of sea-level rise occurs.
A detailed study and mapping of the Neogene volcanosedimentary rocks cropping at the Bahía San Nicolás, Baja California Sur, was carried out, allowing reconnaissance and formal description of the San Nicolás Formation (a lithostratigraphic unit constituted from older to younger by the lower Toba San Antonio, Los Volcanes, Arroyo Amarillo, and the upper El Saucito members). These units reflect syn-to-postextensional episodes associated to the Gulf of California Province that show initial high subsidence onto dry land associated with low rates of sedimentation followed by shallow marine water deposition dominated by storm and macro tidal processes. The maximum age assigned to the units is 3.3 ± 0.5 Ma.
This study assesses patterns of biogenic carbonate sediment production associated with three different reef and reef-related settings at Danjugan Island in the Philippines. Sediments were collected along transects on windward and leeward sides of the island (1–28-m depth) and from a semirestricted lagoon (1.5–2.5-m depth). Sediment assemblages from all sites are dominated (in decreasing order of abundance) by coral (29.1%), Halimeda (28.8%), mollusks (13.5%), and benthic foraminifera (10.2%). Sediments from windward sites are dominated by fragments of corals (15.0–42.5%), Halimeda (14.0–32.1%), mollusks (8.5–21.6%), and benthic foraminifera (7.8–32.9%). Bryozoans represent a significant secondary component (2.77–14.6%). Leeward sediments primarily comprise coral, Halimeda, and molluscan grains, although are characterized by a higher abundance of Halimeda (29.7–49.2%) than the windward transect. Lagoon sediments comprise primarily coral (1.3–42.7%) and Halimeda (13.8–37.2%) in the outer lagoon, but a high proportion (29.8–61.8%) of fine-grained unidentified detrital (probably terrestrially derived) material at inner lagoon areas. Across each transect, sediment compositional and textural characteristics exhibit marked bathymetric variations. Coral, Halimeda, benthic foraminifera, and mollusks dominate windward and leeward reef flats, whereas coral and Halimeda dominate deeper reef-slope settings. Mean grain size generally decreases with depth and sorting increases with depth. Multivariate analysis of percentage similarity delineate the following facies groupings; windward and leeward reef slopes, windward and leeward reef flats, and inner and outer lagoon. These assemblages are likely to reflect not only rates of production by individual sediment contributors but also subsequent physical reworking of grains and the preferential transport of more buoyant sediment particles.
The population dynamics and secondary production of the cirolanid isopod Excirolana braziliensis are compared between two distinct sandy beaches. Monthly sampling from June 1998 through July 2000 was carried out at Grumari (a reflective beach with coarse sand and steeper slope) and Restinga da Marambaia (an intermediate beach with fine sand and moderate slope), both located in Rio de Janeiro State (23° S), southeastern Brazil. Sampling was conducted according to a systematic design in which two transects (fixed 500 meters apart) were established, each with 10 equally spaced sampling strata. From each stratum, five replicates (0.04 square meters) were taken. Highest population abundances were observed in spring and summer on both beaches. The beaches differed significantly in physical parameters and the characteristics of their inhabitant populations: (1) Grumari Beach had a steeper slope, coarse sands, and a short swash period; (2) the abundance of total population, fecundity at length, and egg production potential were higher at Restinga da Marambaia; and (3) individual growth of males was higher at Grumari. Mean length at sexual maturity (L50%), mortality, growth of females, secondary production, and mean annual biomass did not show significant differences between beaches. Variations in population parameters of E. braziliensis might be regulated by phenotypic adjustment to local conditions, optimizing fitness, and especially enabling species to adapt to different physical conditions.
Foraminiferal and sedimentary data, supplemented with geochemical dating and ground-penetrating radar transects, show that the barrier island at Pea Island National Wildlife Refuge just north of Rodanthe, North Carolina, has been dominated by a combination of inlet and overwash processes for at least 1000 years. The stratigraphic record of several vibracores does not preserve every, or even many, overwash events but, instead, is characterized by three to four fining-upward sequences. The last three commence with overwash sand or gravel that is overlain by a variety of finer-grained estuarine, inlet, and marsh deposits. The dynamic nature of this segment of the Outer Banks was muted in the late 1930s by construction of artificial barrier dune ridges, extensive planting of grass and shrubs, and construction of Highway 12 in 1953. Subsequently, the road and barrier dune ridge were rebuilt and relocated several times following storm events.
Historical sources indicate that, in the late 19th century, the portion of the southern California coastline between Palos Verdes Peninsula and San Mateo Point was composed of a series of barrier spits backed by estuaries, beaches backed by cliffs, and occasional rocky headlands. Nearly natural conditions, a reflection of minimal human impact, prevailed during this relatively stormy interval. US Coast [and Geodetic] Survey materials, early scientific work, newspaper articles, and the accounts of travelers provide much of the information utilized to reconstruct the shoreline. Serving as a major roadway, the beach that extended between San Juan Creek and San Mateo Creek was especially well known. The barrier spits were capped by low dunes and were separated by migrating inlets connecting the ocean with the backing estuaries. Rivers discharged into the estuaries at times, decreasing salinities and depositing sediments. Rocky coastlines are believed to have experienced substantial erosion as high levels of bioerosion and vigorous attack by storm waves is inferred, giving rise to notched cliffs, sea caves, and other erosional forms. Forming part of the seaward fringe of the greater Los Angeles region, today this shoreline is completely developed, serving the commercial and recreational needs of millions of residents and visitors.
The construction and economic aspects of two demonstration in-home hurricane resistant retrofit rooms are presented in this paper. The retrofit rooms are a stepped down economic alternative to the U.S. Federal Emergency Management Agency (FEMA) Torando Safe Room, with reasonable hurricane protection. The retrofitting is achieved through reinforcing existing walls and roofs of typical small interior rooms with plywood sheets, steel plates, anchor bolts, and hurricane straps. The in-house shelter offers significant occupant protection and reduces the demand on public shelters in the event of a Category 5 hurricane or F2 level tornado. The smaller size of the Hurricane Rooms makes them well suited to typical small interior spaces in existing homes. The relative construction aspects of plywood versus steel plate wall and ceiling retrofitting are discussed. The average material and labor cost of the two hurricane Retrofit Rooms was about $3100, almost half of the typical cost for a FEMA Tornado Safe Room.
Demographic and life-history attributes of the yellow clam, Mesodesma mactroides, were analyzed along exposed sandy beaches of the Atlantic coast of South America, from Brazil (32°S) to Argentina (41°S), covering most of its geographical range (24–41°S). Population features varied markedly within this range and exhibited systematic geographical patterns of variation. Abundance and growth/mortality rates significantly decreased from northern (Brazil and Uruguay) to southern (Argentina) populations. Snapshot information at the edge of its northern geographical range suggests a large-scale unimodal distribution pattern. Northern populations also had an extended or quasi-continuous recruitment season, whereas Argentinean populations had seasonal recruitment that became negligible at the southernmost edge of the range (41°S). Maximum individual sizes increased nonlinearly with latitude. This result, when considered together with density patterns, provided the second large-scale evidence of scaling of population density to body size in a sandy-beach population. Lifespan increased with latitude, ranging between 3 and >7 years. Length frequency-distribution analysis revealed marked intra-annual growth patterns for two populations located 7° latitude apart. Variations in water temperature explained large-scale differences in the demography and population dynamics of the yellow clam, and the high plasticity over latitudinal gradients leads to an adjustment of the phenotype–environment relationship. Long-term studies in Uruguayan beaches suggest that wide population fluctuations are the result of intertwined forces of environmental, density-dependent, and human-induced factors operating together at different spatiotemporal scales. As this species with planktonic larvae is structured as a metapopulation, future studies should incorporate a number of hierarchical scales to better understand macroscale variations in demographic patterns and life-history traits.
More than one type of shoreline indicator can be used in shoreline change analyses, and quantifying the effects of this practice on the resulting shoreline change rates is important. Comparison of three high water line (proxy-based) shorelines and a mean high water intercept (datum-based) shoreline collected from simultaneous aerial photographic and lidar surveys of a relatively steep reflective beach (tan β = 0.07), which experiences a moderately energetic wave climate (annual average Hs = 1.2 m), reveals an average horizontal offset of 18.8 m between the two types of shoreline indicators. Vertical offsets are also substantial and are correlated with foreshore beach slope and corresponding variations in wave runup. Incorporating the average horizontal offset into both a short-term, endpoint shoreline change analysis and a long-term, linear regression analysis causes rates to be shifted an average of −0.5 m/y and −0.1 m/y, respectively. The rate shift increases with increasing horizontal offset and decreasing measurement intervals and, depending on the rapidity of shoreline change rates, is responsible for varying degrees of analysis error. Our results demonstrate that under many circumstances, the error attributable to proxy-datum offsets is small relative to shoreline change rates and thus not important. Furthermore, we find that when the error associated with proxy-datum offsets is large enough to be important, the shoreline change rates themselves are not likely to be significant.
A total water level model reveals that the high water line digitized by three independent coastal labs for this study was generated by a combination of large waves and a high tide several days before the collection of aerial photography. This illustrates the complexity of the high water line as a shoreline indicator and calls into question traditional definitions, which consider the high water line a wetted bound or “marks left by the previous high tide.”
The modern Huanghe Delta was formed by a huge amount of sediment from the Loess Plateau accumulating in the shallow shelf of the Bohai since 1855. In 1976, the terminal channel of the Huanghe River shifted southeastward from the Diaokou course to the Qingshuigou course, and significant deltaic erosion has emerged on the abandoned Diaokou delta lobe since then. This article presents a wave climate modeling over the modern Huanghe delta based on the mild-slope equation. The calculated wave characteristics and wave-induced bottom shear stress show good agreement with the coastal erosion of the abandoned Diaokou delta lobe. The cross-shore bathymetric and hydrologic data, suspended sediment distribution, and satellite image were analyzed comprehensively to illustrate the deltaic erosion and its hydrodynamics mechanism. The protuberant topography of the abandoned Diaokou delta leads to a convergence of wave energy in the shallow coastal region, with a water depth ranging from 4 to 10 meters, which results in resuspension of the bottom sediment due to high bottom shear stress. The wave processes reshape the subaqueous delta slope into an equilibrium profile with gentle steepness to match the dynamic regime. The high-turbidity zone revealed by the field investigation and satellite image indicates that the suspended sediment in the high-turbidity zone was resuspended from the bottom but not dispersed from the river effluent. The resuspended sediment was transported by the interaction of waves and strong tidal currents in this area, some of which moved down-slope and accumulated in the lower slope as a result of the reshaping process.
Hydrological statistical data, remote sensing images, and bathymetric charts were used to study the recent evolution of the Huanghe (Yellow) River delta under human-induced interventions. It was clear that water and sediment discharge from the Huanghe River had dropped rapidly since 1970, particularly after 1986. The water and sediment discharges for the period of 1986–2000 were found to have been reduced to only 29.2% and 31.2% of those in the period of 1950–69. This was caused by human factors in the upper and middle reaches of the Huanghe River, including water diversion, damming and reservoir construction, and water and soil conservation. Based on the results from visual interpretation of processed Landsat (MSS or TM/ETM ) images dated from 1976 to 2001 and two digital elevation models generated from bathymetric charts surveyed in 1976 and 1992, we found that human-induced reduction of water and sediment discharge led to coastline retrogradation, with the maximum mean recession rate of −0.51 km yr−1 over the period of 1976–98, and seabed erosion beyond the −20 m isobath between 1976 and 1992. Other impacts of human activities on the recent evolution of the Huanghe River delta, including tidal flats shrinking, artificial coastline increasing, land surface sinking and so on, were also analyzed. We found that: (i) the whole delta, including subaerial and subaqueous, has turned from a highly constructive period to a destructive phase; (ii) channelization and dredging were two of the main causes of delta destruction; (iii) land loss in the Huanghe River delta caused by submersion will be increased in the near future; (iv) the Huanghe River delta was becoming more fragile and susceptible to natural hazards.
Coring in the Lagoon of Venice mudflats along previously collected high-resolution subbottom seismic-reflection survey profile lines has enabled the collection of interlayered radiocarbon-datable terrestrial plant material. Along present and former meander bends, dipping laminated sandy channel-bank deposits rest in sharp lithostratigraphic and chronologic contrast to the adjacent and overlying mudflat deposits. Horizontal channel migration rates of roughly 10 to 20 meters per century are orders of magnitude faster than the minimum estimates of vertical mudflat silt accumulation, which range from 5 to 25 centimeters per century. Given the nearly 6000-year history since the late-Holocene marine transgression that produced the initial lagoon environments of deposition, it is no surprise that channel meander migration has left a prevalence of channel-bank deposits in the subsurface lithostratigraphy. Furthermore, regional subsidence and rising relative sea level continue to enhance the net accumulation of mudflat and salt marsh deposition on top of the older deposits. Tapered variations of tidal-channel width, depth, and flow velocity, as well as wind-driven waves with associated intensities of turbulence along the meandering paths, lead to recognizable sediment grain size trends and lagoon deposit stratigraphy. Human interventions, such as dredging, spoil disposal, and powerboat wakes, introduce other contrasting processes and depositional features. For complete understanding of the depositional environments in the lagoon, the full set of dynamic processes and depositional consequences often need to be considered. Patterns and processes revealed in this case study probably have broad applicability to other coastal lagoon environments experiencing significant tidal flow and sea-level change.
Integrated coastal zone management (ICZM) is widely recognised as a key mechanism for asserting sustainable development objectives within coastal areas. However, despite significant developments in ICZM practice and development, a number of challenges remain. Particular concerns relate to the existence of a limited understanding of the relationship between biophysical and socioeconomic processes and poor mechanisms for institutional coordination. This article explores the contribution that strategic environmental assessment (SEA) can make as a decision-making tool for integration within ICZM. Through the adoption of systematic “tiered” assessment procedures, it is argued that SEA can help identify and mitigate competing development pressures.
Turkey is bordered on three sides by the sea and has a long coastline. Çanakkale is one of the most important cities of Turkey, with its natural, cultural, and historical characteristics. With a 750-kilometer-long coastline and the Dardanelles, one of the most important waterways of the world, this part of the country has historically been an attractive area. The Kordonboyu coastal area, ca. 2 kilometers long, is the most important attraction in the city. Located east of the Dardanelles, the study area has always been a center of interest.
The aim of this investigation was to determine the negative effects of settlement, industry, trade, or similar activities associated with a rapid increase in city population on the coastal structure of Çanakkale and to provide suggestions for rearrangement studies with sustainable planning approaches.
The study was carried out in two stages by collecting and analyzing data. In this study, the factors that affect planning in the city (natural factors, demographic structure of the population, socioeconomic structure) have been inspected. Current land uses in the Kordonboyu coastal area and environs have been analyzed. Also, to determine the inclinations of the people of Çanakkale toward current land use of the research area, a questionnaire was made. Chi square analysis showed that the relationships between age groups and other parameters were significant (p < 0.05).
The data taken from the questionnaires show that the Çanakkale community is concerned with land use and has a desire to live in a modern and well-arranged city. For this reason, the local administrations that are in a position to make decisions on land use policy should conduct studies that will take ecological criteria into account.
Twenty-six parameters have been selected that delineate coastal scenery. These were obtained via consultation between coastal users and experts in the field. The parameters were assessed as to their priorities and weightings given. Application of fuzzy logic techniques enabled a decision parameter (D) to be calculated for any coastal scene. Over 100 worldwide coastal sites were analysed via the technique and a five-class differentiation obtained from D values.
A critical review is presented on the state of knowledge and calculation capability for coastal overwash. Overwash and overwash deposits (washover) accompanying hurricanes and severe storms can devastate coastal communities and habitat, but in many areas these processes are essential for maintaining the integrity of barrier islands while creating new habitat. This review covers general studies of overwash processes, studies from a geological perspective, physical modeling, field studies including measurements of washovers and related hydraulics, and the state of numerical modeling capability to predict overwash. Although significant literature exists describing individual overwash events and locations experiencing frequent overwash, complete hydrodynamic and morphologic documentation of an overwash event is lacking. A limited number of algorithms or models exist to quantify overwash occurrence, deposited sand volume, and upper beach profile evolution. Existing models of overwash occurrence and one-dimensional beach profile evolution have been shown to perform successfully against available data, and areas of improvement are identified. Models must be made capable of simulating the various washover morphologies that have been produced by different hydrodynamics, overwash spreading based on dune topography, friction and percolation, and interaction between swash bores. Comprehensive laboratory and field data sets to achieve these aims are still lacking.
While observing the hydrodynamics and geomorphology of the entrance to Burrill Lake, a small estuary on the south coast of New South Wales, Australia, a striking vortex phenomenon was observed. This vortex is described and interpreted.
Beach profiles provide useful information for coastal monitoring studies and management processes. In 1961, Emery proposed a simple method of beach profiling based on the use of two graduated rods, whose alignment and reading of the intersection with the horizon allow for the determination of differences in level along the profile. In spite of some shortcomings, and because of its simplicity and low cost, researchers and volunteers alike use the “Emery method” in monitoring studies of sand dunes and beaches, mainly in the USA. Modern techniques in current usage are expensive and require specialized technicians.
An alternative method is presented, based on the physical principle of communicating vessels, that consists of the sequential measurement of differential elevation as read on two graduated rods connected by a hose filled with water.
In terms of accuracy, this method compares favorably with standard topographic instruments, having significantly lower costs, higher portability, and greater ease of use and constitutes a valid alternative to the Emery method. It is faster, because the distance between the rods is adjustable to the shape of the beach and to the amount of detail required; does not need a visible horizon, allowing its use in lakes and in situations of limited visibility caused by beach relief or weather conditions; and requires no correction for the Earth's curvature.
The method's simplicity makes it appropriate for use by volunteers in the collection of relevant data for the study and management of coastal zones, contributing to the environmental and scientific education of the participants.
A comparison has been made of sand, silt, and clay percentage of 118 samples from the Ayeyarwady continental shelf, northern Andaman Sea, measured by the sieve–laser diffraction technique and by classical sieve-pipette methods. Clay and silt percentages determined by Malvern Mastersizer 2000 Laser Particle Size Analyzer are 37% and 157% of pipette clay and pipette silt percentages, respectively. Clay particles separated by the settling technique and having an apparent size of less than 2 µm when measured with laser diffraction show that 99% of the particles have an upper size range between 4.8 and 7.7 µm. A calibration relationship between pipette and laser diffraction techniques has been developed for the northern Andaman Sea. A clay particle size of 2 µm defined by the pipette technique corresponds best to a size of 6.2 µm defined by laser diffraction. For the laser data, when 6.2 µm is taken as the boundary between silt and clay, the results are comparable to pipette analysis. Use of the calibration relationship enables one to make use of the rapid laser diffraction size analysis technique for routine sediment texture analysis with high precision.
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