Watson, P.J., 2019. Updated mean sea-level analysis: South Korea. Journal of Coastal Research, 35(2), 241–250. Coconut Creek (Florida), ISSN 0749-0208.

The threat of sea-level rise to the heavily populated Korean Peninsula has profound and far-reaching implications. This study updates and extends the several previous works undertaken to analyse tide-gauge records and satellite altimetry around South Korea using enhanced time-series analysis techniques to detect coastal vertical land motion and current rates of rise and accelerations in mean sea level to augment planning, design, and risk management activities. Although the longest tide-gauge records available only date back to 1960, every effort has been made to separate the mean sea-level trend from the more dynamic influences with improved precision using state-of-the-art analytical techniques. The analysis identified general trends of subsidence observed around the margins bounded by the East China Sea and East Sea (Sea of Japan) below 36°N, whereas uplift was a more prevalent feature along the margins bounded by the Yellow Sea. All tide-gauge records longer than 50 years exhibited ‘relative’ mean sea-level rise increasing marginally over the length of the record, suggesting the presence of an acceleration; however, the estimated time-varying accelerations (albeit predominantly positive) are small and not statistically different from zero (95% confidence interval). Although the average trend of sea-surface height from satellite altimetry across this region was 3.2 mm/y, key spatial variations were evident, with the highest rates of rise centred in two discrete areas east and west of South Korea around 37.5°N, each exceeding 8 mm/y.

Caudle, T.L.; Paine, J.G.; Andrews, J.R., and Saylam, K., 2019. Beach, dune, and nearshore analysis of southern Texas Gulf Coast using Chiroptera LIDAR and imaging system. Journal of Coastal Research, 35(2), 251–268. Coconut Creek (Florida), ISSN 0749-0208.

LIDAR data and color infrared aerial imagery were acquired for southern Padre Island and Brazos Island, Texas, in 2013 to calculate rates of shoreline change; analyze beach-dune system volume; and test bathymetric LIDAR capabilities along the Texas Gulf of Mexico shoreline. Data were acquired using a Chiroptera airborne system, which simultaneously collects topographic and bathymetric LIDAR and high-resolution imagery. Shoreline position was extracted from LIDAR digital elevation models (DEMs) to compare with historical shoreline positions for shoreline change analyses. Long-term rates (1937–2013) of gulf shoreline change for southern Padre Island and Brazos Island averaged 2.2 m/y of retreat, with 86% of sites retreating. Retreat rates decreased over the last decade (2000–13) to 1.1 m/y (76% of sites retreating). The trend changed between 2010 and 2013: 64% of monitoring sites advanced at an average distance of 4.9 m. Beach and dune volumes above threshold elevations (1 to 6 m above mean sea level) were extracted from DEMs to assess geographic and temporal patterns of sand storage. The undeveloped area of southern Padre Island had 2 to 4 times the volume of sand at lower threshold elevations and 7 times the volume at higher elevation thresholds than did the heavily developed southernmost section of the island. A constant trend across the study area is that volume reduced by approximately half with each 1 m increase in threshold elevation. Beach and dune system volume in the study area increased steadily since 2000, mirroring the decreased retreat rates observed in the shoreline movement analysis. Possible causes of the decreased shoreline retreat rates and increased subaerial sand storage are a lack of tropical cyclone impacts to the study area during the most recent periods, as well as sediment contribution from beach nourishment activities. Bathymetric LIDAR detected the seafloor in low-turbidity areas less than 4 m deep.

Bell, T.; Lander, M.A.; Jenson, J.W.; Randall, R.H.; Partin, J.W., and Prouty, N.G., 2019. A 50-year Sr/Ca time series from an enclosed, shallow-water Guam coral: In situ monitoring and extraction of a temperature trend, annual cycle, and ENSO and PDO signals. Journal of Coastal Research, 35(2), 269–286. Coconut Creek (Florida), ISSN 0749-0208.

Located on the northern edge of the West Pacific Warm Pool and having a developed economy and modern infrastructure, Guam is well positioned and equipped for obtaining natural records of the west Pacific maritime paleoclimate. This study was a proof of concept to explore whether useful climate proxy records might be obtained from coral at readily accessible, even if geochemically nonoptimal, coastal sites. A 50-year Sr/Ca record (1960–2010) was thus obtained from a shallow-water, near-shore Porites lutea colony at a recreational facility inside Guam's Apra Harbor and compared with local and regional meteorological records, including the El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) indices. The accessibility of the site enabled documentation of relevant environmental variables for 16 months (September 2009–December 2010): seawater δ¹⁸O, pH, seawater cations, and nitrate. Time series of seawater δ¹⁸O, pH, and cations show evidence of freshwater input from direct rainfall and stream discharge into the harbor. An anomalously higher mean and variable concentrations of Ba suggest the presence of river-borne, fine-grained terrigenous sediment. Nevertheless, the Sr/Ca time series reproduces a long-term warming trend seen in historical records of local air temperature and regional sea-surface temperature (SST) and closely tracks the ENSO and PDO indices over the entire 50-year record. The consistency of the results with Guam's historical instrumental records, previous coral δ¹⁸O results from Guam obtained by others, and previous Sr/Ca proxy results for SST in similar environments elsewhere demonstrate that accessible near-shore sites—where environmental conditions can be monitored—can produce useful Sr/Ca records of local and regional climate phenomena.

Wang, T. and Yang, Z., 2019. The nonlinear response of storm surge to sea-level rise: A modeling approach. Journal of Coastal Research, 35(2), 287–294. Coconut Creek (Florida), ISSN 0749-0208.

With the use of a simplified prototype model domain and a dynamic modeling approach, this study shows that storm surge responds to sea-level rise (SLR) nonlinearly and the spatial distribution of the nonlinearity can be generalized as three distinct regions across the land-ocean boundary near the hurricane track. In particular for the lower floodplain region, compared with the baseline condition without SLR, the increment in the storm surge height under the SLR condition can be twice the SLR rate as a result of nonlinear amplification. This result highlights the necessity for designing more robust coastal infrastructure to mitigate the effect of storm surge in the context of SLR.

Carassai, J.J.; Lavina, E.L.C; Chemale, F., Jr., and Girelli, T.J., 2019. Provenance of heavy minerals for the Quaternary coastal plain of southernmost Brazil (Rio Grande do Sul State). Journal of Coastal Research, 35(2), 295–304. Coconut Creek (Florida), ISSN 0749-0208.

During the Quaternary, an extensive barrier system was developed in southern Brazil and northern Uruguay. The patterns of variation in the distribution and behavior of heavy minerals present in the aeolian and marine (upper shoreface-foreshore) facies of the four barriers formed in the Rio Grande do Sul costal plain were identified. Minerals were analyzed by scanning electron microscopy, including epidote, tourmaline, zircon, magnetite/ilmenite, polymorphs of aluminum silicates (andalusite, kyanite, and sillimanite), staurolite, rutile, amphibole, pyroxene, corundum, perovskite, chromite, garnet, apatite, monazite, xenotime, spinel, and titanite. In all of the barriers, zircon, magnetite, and ilmenite are the most important, followed by chromite, garnet, rutile, tourmaline, staurolite, and epidote. In total, heavy minerals indicate two primary sources in the coastal plain: (a) direct feeding from the rocks of Uruguay and Rio Grande do Sul Shield and Paraná Basin, drained by Rio Camaquã and Rio Jacuí; and (b) indirect feeding from rocks of the Andean province, drained by Rio Paraná and Rio La Plata estuary in northern Argentina. During low sea level, rivers flowed directly into the continental shelf, and their deposits were reworked during subsequent transgressive stages. Throughout this region, the atmospheric circulation pattern forms a NW oceanic swell, generating a longshore current with dominant northward direction. Thus, several transgressive-recessive pulses associated with Pleistocene glacial events pushed large volumes of sediments northward, giving rise to the present southern Brazil coastal plain.

Piña-García, F.; de Luis-Ruiz, J.M.; Castillo-López, E.; Pereda-García, R., and Pérez-Álvarez, R., 2019. Demarcation of coastal municipalities in Spain. Journal of Coastal Research, 35(2), 305–313. Coconut Creek (Florida), ISSN 0749-0208.

The demarcation of municipalities is essential for an adequate functioning of local administrations and the exercise of other public functions, such as jurisdiction, spatial planning, and urbanism. This research emphasizes the definition of municipalities in coastal areas, understanding that the beaches and the maritime–terrestrial zones are part of them. The limits of the beaches and the maritime–terrestrial zones are hard to determine, and the hydrographic zero is defined as an abstract line that separates terrestrial from marine. This line is difficult to define and even worse to materialize as it is a fractal object (too irregular for a geometric definition) and, in some cases, undergoes great changes through time. By analogy with what is done with normal baselines, which allow straight lines, or with the demarcation of the inner limit of the maritime–terrestrial public domain, it is proposed to identify the border of the municipality as a polygonal line whose vertices are defined by coordinates. A strictly administrative demarcation is thus proposed, which should neither modify the maritime–terrestrial public domain nor affect the inner waters or the territorial sea. As a result of the application of this methodology, the boundaries of a municipality would be defined and, therefore, its area. The proposal is applied to a practical case: the municipality of Ribamontán al Mar (Cantabria, Spain). Both the ambiguity of data and the imprecisions among the several sources of information regarding its boundary with respect to the sea are analyzed. A polygonal line defined by coordinates is proposed. This procedure could be generalized for the boundaries of any coastal municipality.

Lyu, H. and Zhu, J., 2019. Impacts of tidal flat reclamation on saltwater intrusion and freshwater resources in the Changjiang Estuary. Journal of Coastal Research, 35(2), 314–321. Coconut Creek (Florida), ISSN 0749-0208.

A well-validated numerical model, residual water and salt transport, and the water diversion ratio between channels as well as their variations were used to simulate and analyze the impacts of the tidal flat reclamation project in the Eastern Hengsha Shoal (RP-EHS) on saltwater intrusion and freshwater resources. The RP-EHS is the largest tidal flat reclamation project in the Changjiang Estuary and has significantly changed the local topography. The RP-EHS results in a net transection water flux increase in the North Channel and decreases in the South Channel, North Passage, and South Passage, which weaken the saltwater intrusion in the North Channel and enhance the saltwater intrusion in the South Channel, North Passage, and South Passage. The saltwater intrusion in the North Branch and the saltwater spillover from the North Branch into the South Branch were increased after the establishment of the RP-EHS. There are three reservoirs in the Changjiang Estuary, which provide more than 80% of the freshwater to Shanghai. Because the saltwater sources of the reservoirs mainly originate from the saltwater spillover, the salinity at the water intakes of the three reservoirs slightly increased after the project, which means that the project is unfavorable for water resources in the Changjiang Estuary. The reservoirs are important for Shanghai's water supply, and the impacts of the tidal flat reclamation on water resources should receive greater attention to ensure water safety.

Sun, C.; Liu, Y.; Jin, S.; Wang, Y., and Wei, X., 2019. Using time-series HSI mapping to determine ecological processes and driving forces of red-crowned crane (Grus japonensis) habitat in the Yancheng Biosphere Reserve (China). Journal of Coastal Research, 35(2), 322–334. Coconut Creek (Florida), ISSN 0749-0208.

It is generally accepted that biodiversity will be better protected from anthropogenic disturbances after a region has been designated as a protected area. However, this common perception is not true in the case of the Yancheng Biosphere Reserve (YBR), which is widely regarded as the largest wintering habitat in the world for red-crowned cranes. Combining previous information with multisource remote sensing data, this study constructed a highly accurate habitat suitability index (HSI) model and produced a series of HSI hierarchical maps to fill in the blanks of long-term monitoring and regular data acquisition in the YBR. Based on the integrated methods of geographic information system analysis, landscape indices, and redundancy analysis, this study characterized the entire process of shrinkage and deterioration of the habitats of red-crowned cranes and revealed the underlying driving forces. The results can be summarized as follows: (1) The total area of suitable and secondary suitable habitats decreased significantly, from 43.3 to 24.6%, during 1991–2013, and suitable habitats became increasingly concentrated in the core zone. (2) The ecological quality of the habitats was significantly degraded, as reflected by increasing fragmentation, isolation, and scattering of suitable and secondary suitable habitats, as well as by expansion and aggregation of marginal suitable and unsuitable habitats. (3) The extensive transformation of the original natural wetlands to aquafarms is the main reason for habitat shrinkage, with construction of buildings and overall increased intensity of human activity being significantly responsible for the ecological deterioration.

Xiao, K.; Li, H.; Song, D.; Chen, Y.; Wilson, A.M.; Shananan, M.; Li, G., and Huang, Y., 2019. Field measurements for investigating the dynamics of the tidal prism during a spring-neap tidal cycle in Jiaozhou Bay, China. Journal of Coastal Research, 35(2), 335–347. Coconut Creek (Florida), ISSN 0749-0208.

The tidal prism is a crucial environmental index for evaluating the water self-purification capacity in semi-enclosed bay systems, but quantitative studies linking spring-neap tidal variations are few. In this paper, field measurements of the tidal level and tidal flux were conducted in Jiaozhou Bay (JZB) to estimate the hydrodynamic and tidal prism variations during a spring-neap tidal cycle. JZB is located on the south coast of Shandong Peninsula, China, with a narrow inlet of 3.1 km width, which was accessible for continuous shipboard Acoustic Doppler Current Profiler measurements over 15 days. Unfortunately, due to the violent sea induced by typhoon “Chan-hom,” the measurements were suspended for 2 days. However, the fluxes during the temporary suspension were reproduced using the significant linear relationship between the inlet fluxes and the changes in tidal level (r² = 0.94, P < 0.001), without considering the storm surge. The relationship between tidal range and tidal prism was also linearly correlative (r² = 0.69, P < 0.001), indicating that the tidal prism was primarily controlled by the tidal range in JZB. These linear relationships are well verified by historical data in JZB. Compared with previous studies in JZB, the tidal prism has decreased 26% from 1928 to 2008. The decreased intertidal areas, caused by large-scale land reclamations, were likely responsible for the decrease in the tidal prism, which in turn weakened the self-purification capability and triggered the chronic pollutant enrichment. However, the tidal prism increased 4% from 2008 to 2015 as the restoration of water area through protective policies formulated by government. These findings will contribute to designing maintenance strategies for reducing human activity impacts on the health of JZB in the future.

Chen, B. and Li, S.W., 2019. Temporal variation of live-bed pier scour under combined wave-current flow in a large-scale flume. Journal of Coastal Research, 35(2), 348–356. Coconut Creek (Florida), ISSN 0749-0208.

Studies on the temporal variation of live-bed scour under waves alone and combined wave-current flow are not as extensive as those under current-alone conditions. Motivated by this, series of experimental tests were carried out in a large-scale flume (5 m wide, 8 m deep, and 450 m long). The scour processes in different locations of the scour hole were monitored simultaneously during the tests. Measured data indicated that the scour depth versus time can be expressed by an exponential equation for both waves-only and combined wave-current conditions. A piecewise equation for predicting the characteristic timescale under combined wave-current flow is proposed based on the data from the literature and the present experiment. In live-bed scour, the effect of wave-generated ripples on scour depth fluctuation could be ignored under waves alone. For the combined wave-current flow, the fluctuation amplitude of scour depth was approximately equal to the height of bed forms under current-dominated conditions and nearly half of the observed height of the bed forms in wave-dominated conditions.

Bortolin, E.; Weschenfelder, J., and Cooper, A., 2019. Holocene evolution of Patos Lagoon, Brazil: The role of antecedent topography. Journal of Coastal Research, 35(2), 357–368. Coconut Creek (Florida), ISSN 0749-0208.

The Patos Lagoon in Rio Grande do Sul, Brazil, is part of the largest barrier lagoon system in the world. It is enclosed by a 400-km-long composite late Pleistocene/Holocene sandy barrier and has a single tidal inlet. The modern lagoon is shallow (average < 5 m) and is dominated by silt deposition. More than 1000 km of shallow seismic data (3.5 kHz) indicate that the lagoon is underlain by several shore-normal incised valleys separated by interfluves. Each incised valley existed as an individual estuary since its first flooding during the mid-Holocene. The infill of these valleys contains a basal fluvial unit, a central estuarine mud unit, and locally developed tidal sand bodies associated with former tidal inlets. The contemporary lagoonal sediments form a blanketing upper unit. Ultimately, the interfluves were drowned and the contemporary lagoon was formed by the coalescence of the incised valley estuarine systems in the late Holocene. This expansion of accommodation space coincided with a dramatic reduction in vertical sedimentation rates. Seismic profiling reveals the contemporary sandy spits, and their subaqueous extensions coincide with the location of former interfluves, indicating that inherited topography exerts major control over the location and development of lagoon-marginal spits.

Begum, S.; Abele, D., and Brey, T., 2019. Toward the morphometric calibration of the environmental biorecorder Arctica islandica. Journal of Coastal Research, 35(2), 369–375. Coconut Creek (Florida), ISSN 0749-0208.

Owing to its extremely long life span and occurrence in the entire North Atlantic, the Arctic boreal Arctica islandica has become of particular significance for monitoring the environment, because information on past environmental conditions is archived in morphological and biogeochemical properties of the calcareous shell. To evaluate whether such properties are comparable between different localities, shell and soft body morphometry of six A. islandica populations, Norwegian Coast, Kattegat, Kiel Bay (Baltic), White Sea, German Bight (North Sea), and off NE Iceland, were compared. Discriminant analysis indicated distinct differences between populations, albeit not related to geographical distance, but more likely to local hydrography, bottom morphology, and food regime.

Thomas, J.; Velamala, S.N., and Prasad, K.V.S.R., 2019. Numerical simulation of tidal constituents in Thane Creek and the Ulhas estuary, west coast of India. Journal of Coastal Research, 35(2), 376–388. Coconut Creek (Florida), ISSN 0749-0208.

Complex tidal progression in creeks and estuaries attract a large number of researchers around the globe. The main motive of the present work is to study the complex tidal variation of Thane Creek and the Ulhas estuary on the west coast of India. A Delft3D model was applied to simulate its depth-averaged hydrodynamics and tidal propagation along the system, and the calibration and validation of this model revealed its accuracy. The system was classified as hyposynchronous; a gradual decrease in the amplitude was noticed from mouth to upstream in all seasons. The interpretation of the major tidal constituents amplitude and phase, shallow water constituents, form number, and tidal asymmetry showed the dynamic nature of the system. The form number results revealed that the tide in Thane Creek and the Ulhas estuary is mixed semidiurnal. The tidal asymmetry parameter indicated a seasonal variation of ebb and flood current in Thane Creek and the Ulhas estuary, which favors sedimentation processes in the system with consequent erosion and deposition. For the future, these results will help in understanding sediment transport and the corresponding shoreline changes and the biogeochemical processes of this dynamic system and help to establish its sustainability.

Hale, H.; Jacques, R.O., and Tolhurst, T.J., 2019. Determining how functionally diverse intertidal sediment species preserve mudflat ecosystem properties after abrupt biodiversity loss. Journal of Coastal Research, 35(2), 389–396. Coconut Creek (Florida), ISSN 0749-0208.

As a result of anthropogenic climate change, extreme climatic events have increased in frequency, severity, and longevity. The consequences for community structure after a catastrophic event have been well studied. However, changes in ecosystem functioning that occur after such an event, including ecosystem recovery, are still uncertain. A catastrophic event was simulated in an intertidal sedimentary habitat. Postevent sediment replicates were assigned to one of four recovery scenarios: (1) no recovery, (2) migration recovery, and recovery by differential opportunistic colonisation by (3) the polychaete worm Hediste diversicolor and (4) the mud snail Peringia ulvae, two locally dominant infauna species. These are compared with a control scenario not subjected to the event. The simulated extreme event caused a shift in habitat state due to a reduction in mobile macrofauna abundance and an increase in microphytobenthos biomass. Migratory recovery of species and the simulated opportunistic expansion of a single species ameliorated this shift and, for some metrics, functional compensation for the loss of other species and the preservation of certain ecosystem functions was observed. The dominant species identity during postevent habitat recovery can have considerable effects on important ecosystem processes and functions with consequences that may result in functional regime shifts in a habitat and alter coastal stability.

Lindner, B.L., Climatology and variability of tropical cyclones affecting Charleston, South Carolina, from 1670 to 1850. Journal of Coastal Research, 35(2), 397–409. Coconut Creek (Florida), ISSN 0749-0208.

An improved understanding of the climatology of tropical cyclones helps communities plan for their consequences. Many industries and governmental agencies base risk assessment analysis and cost–benefit analysis upon the frequency of tropical cyclones of varying intensity. The inclusion of earlier periods lengthens the baseline of the climatological data and thus improves frequency estimates, but it also increases the uncertainty therein. To reduce this uncertainty, a limited meta-analysis combined seven previous historical studies to infer the properties of the 78 tropical cyclones that affected Charleston, South Carolina, during the period 1670–1850. Return rates for hurricanes are estimated at 5.2 and 3.8 years for the periods 1670–1850 and 1778–1850, respectively (the latter period is better documented), although uncertainties in the historical record result in large uncertainties in the return rates. Key observations for significant tropical cyclones were used to distinguish those that were likely to have been major hurricanes. The estimated return rate of 12 years for major hurricanes is likely inconsistent with prior studies that show an increasing number of major hurricanes in the modern era in the broader Atlantic Ocean, potentially because of climate change. The period 1778–1850 likely had a return rate of 9 to 10 years for major hurricanes in Charleston, which implies this may have been a particularly active period. The seasonality of tropical cyclones for the period 1670–1850 in Charleston is similar to the seasonality of tropical cyclones in the modern era, except that the median date for major hurricanes is likely significantly earlier during the period 1670–1850. Finally, the apparent lack of a change in the length of the tropical cyclone season over the past three centuries may be inconsistent with prior studies that show climate change may be inducing a seasonal broadening in the nearby Atlantic Ocean.

Zhao, Y.; Zou, X.; Liu, Q., and Chen, Y., 2019. Impacts of climate variability and human activities on streamflow in the Wanquan River Basin along the east coast of Hainan Island, southern China. Journal of Coastal Research, 35(2), 410–419. Coconut Creek (Florida), ISSN 0749-0208.

The influences of climate change and human activities on streamflow change have received significant attention recently. In this study, daily data from seven precipitation gauges and one hydrological station are analyzed to assess the impacts of climate variability and human activities on streamflow over the past 54 years in the Wanquan River Basin (WRB). The Mann-Kendall test and Morlet wavelet method were employed to analyze the streamflow series, and the relative effects of climate change and human activities were empirically determined based on a coupled water and energy budget analysis. The results show that annual streamflow exhibited a statistically insignificant decreasing trend throughout the entire basin at an annual rate of –0.015 × 10⁸ m³/y. Meteorological factors, such as temperature, exhibited significant increases throughout the entire basin. A decreasing trend in precipitation and an increasing trend in potential evapotranspiration were identified in the upstream region, whereas the opposite trends were observed in the downstream region. Moreover, an abrupt change in streamflow at Jiaji station occurred in 1974, exhibiting periodicities of 2 to 4 and 8 to 11 years at a 95% confidence level during the periods of 1965–80 and 1970–75, respectively. Regarding the catchment-averaged water balance, a quantitative analysis revealed that climate change resulted in an increase in streamflow from the 1970s to the 2000s throughout the entire basin, and streamflow increased by 146%, 259%, 473%, and 128% in the 1970s, the 1980s, the 1990s, and 2000–13 relative to streamflow in the 1960s. However, human activities may have decreased streamflow (–46%, –159%, –373%, and –28% in the 1970s, the 1980s, the 1990s, and 2000–13, respectively). Therefore, the relative effect of climate change was greater than that of human activities. Further research is needed to clarify the mechanisms associated with the anthropogenic effects on runoff changes.

Lersundi-Kampistegui, A.V.; Bernabeu, A.M.; Rey, D., and Plaza-Morlote, M., 2019. Bottom suspended particulate matter dynamics in a ría environment under fair-weather conditions: Ría de Vigo (NW Spain). Journal of Coastal Research, 35(2), 420–433. Coconut Creek (Florida), ISSN 0749-0208.

The Ría de Vigo (NW Spain) is an economically important coastal system in which increasing demographic pressure over the last four decades has led to the development of conflicting economic activities, such as industry, fisheries, and tourism. The bottom sediment dynamics in the ría were investigated here for the first time as a key element to address effective coastal management in this context. The turbidity, salinity, temperature, and current were measured by two current meters placed at ∼1 m above the bottom (mab) during 14 days from 28 June 2005 to 11 July 2005. Both stations were placed in the marine sector of the ría, one in the central channel and the other in the outer southern margin. Superficial sediment samples in the surroundings of each site were also analyzed. The survey occurred under low-wave (significant wave height [Hs] < 2 m) conditions with little precipitation, typical of the summer season. The oceanographic observations registered the complete development of an East North Atlantic Central Water (ENACW) upwelling event in the ría. The results indicated that the main suspended particulate matter (SPM) fluctuation was produced in the subtidal timescale and correlated well with the upwelling-produced inward current, rather than with the dominant hydrodynamic processes (tide and waves) at the sampling sites. Punctual, but significant input from runoff was also detected in the channel. Under summer conditions, the advection of the shelf SPM by the upwelling bottom current stands out as the main transport process observed in the marine sector of the ría.

Williams, A.K. and Quigg, A., 2019. Spatiotemporal variability in autotrophic and heterotrophic microbial plankton abundances in a subtropical estuary (Galveston Bay, Texas). Journal of Coastal Research, 35(2), 434–444. Coconut Creek (Florida), ISSN 0749-0208.

The subtropical estuary Galveston Bay (Texas) is influenced by frequent riverine pulses from two important rivers in its northern sector and by ocean tides from the Gulf of Mexico in its southern sector. This study examined combinations of abiotic and biotic factors that synergistically influence spatiotemporal variability of autotrophic and heterotrophic microbial plankton abundances (0.2–20 µm). Potential nutrient limitation observed in situ was supported by in vitro enrichment bioassays. Shifts in the relative in situ abundance of autotrophs and heterotrophs, stained with SYBR Green I and enumerated on a flow cytometer, were significantly related to temperature, total nitrogen, dissolved inorganic nitrogen-to-phosphorus ratios, and total organic carbon concentrations along estuarine gradients. Observations reveal a pattern of serial colimitation of the microbial plankton community. Among the variables tested, nitrogen became the principal limiting factor for growth if phosphorous was available and temperatures were warm. In vitro nutrient enrichment bioassays performed with inorganic nitrogen (as nitrate) and P_i revealed variations in the responses between autotrophic and heterotrophic microbes under nutrient-limiting conditions, particularly during co-occurring phytoplankton blooms. The measured dynamics in planktonic relationships will have important impacts on understanding estuarine nutrient processing.

Mohapatra, S.C.; Gadelho, J.F.M., and Guedes Soares, C., 2019. Effect of interfacial tension on internal waves based on Boussinesq equations in two-layer fluids. Journal of Coastal Research, 35(2), 445–462. Coconut Creek (Florida), ISSN 0749-0208.

An analytical model associated with internal waves in the presence of interfacial tension bounded by a rigid floating plate and rigid bottom in a two-layer fluid is presented based on Boussinesq equations. The general governing equations and boundary conditions of internal wave motion under interfacial tension are described. The detail of the Boussinesq equations associated with interfacial tension with two depth parameters that indicate the specific elevations in upper-and lower-layer fluids are obtained based on an expansion of velocity potentials as a power series in the dispersive effect. For simplicity, the one-dimensional linearized Boussinesq equations and dispersion relation with interfacial tension are obtained. The first- and second-order internal wave amplitudes with interfacial tension based on a perturbation technique are derived, and the super- and subharmonic interactions of second-order internal waves are obtained. The accuracy of the analytical result of internal wave displacement is verified by comparing it with computational fluid dynamics model simulations without introducing interfacial tension, and it is observed that the wave profiles and their peak amplitudes agree well. Furthermore, the linearized dispersion relation is compared with one recently obtained. The influences of interfacial tension on internal wave properties are studied by analyzing dispersion relation, fluid particle velocities, first- and second-order harmonic waves on super- and subharmonic transfer functions, and shoaling gradients. It is found that smaller values of interfacial tension and wavenumber ratio result in stronger second-order effect on the internal wave profile. Finally, an application of interfacial tension is demonstrated in the presence of surfactants for partitioning oil–water interface.

Bassi, D.; Iryu, Y.; Humblet, M.; Matsuda, H.; Machiyama, H.; Sasaki, K.; Matsuda, S.; Arai, K., and Inoue, T., 2019. Deep-water macroid beds of the Ryukyu Islands, Japan: Encrusting acervulinids as ecosystem engineers. Journal of Coastal Research, 35(2), 463–466. Coconut Creek (Florida), ISSN 0749-0208.

Encrusting acervulinid foraminifera can produce centimeter-sized, free-living coated grains named macroids. Macroid beds are an interesting feature of subtidal environments and have been recognized as important carbonate producers, habitat-forming structures, and paleoenvironmental indicators. Macroids provide a hard, three-dimensional substrate serving as microhabitat for a wide range of diverse organisms. As yet, the most extensive known occurrence of macroid beds in the western Pacific Ocean is found on the insular shelf of Kikai-jima, a coral reef–related island in the central Ryukyu Islands. The surveyed beds occur at water depth of 61–105 m arrayed on a ca. 6-km² area. Despite their importance for the benthic communities of the Ryukyu Islands, only in the last decade have sampling efforts led to a more comprehensive understanding of the beds' distribution, their structure and associated communities, and the data concerning the influence of environmental factors on macroid beds and their ecological dynamics. In this study, the available information on the biodiversity associated with the recently described Ryukyu macroid beds are reviewed. This review is intended to inform and influence future research and policy planning on this largely unexplored, highly diverse marine ecosystem.

Sutherland, T.F.; Sterling, A.M.; Shaw, K.L.; Blasco, N.N.J., and Bradford, M.J., 2019. Detecting indicator taxa associated with benthic organic enrichment using different video camera orientations. Journal of Coastal Research, 35(2), 467–479. Coconut Creek (Florida), ISSN 0749-0208.

Two video cameras mounted on a remotely operated vehicle (ROV) were used to generate paired forward-facing (FF) and downward-facing (DF) observations of benthic epifauna along 10 single transects at eight marine finfish aquaculture sites in British Columbia, Canada. The abundance of mat-forming primary indicators of organic enrichment, such as sulphide-oxidizing bacteria and opportunistic polychaete complexes (OPC), were quantified through percentage coverage estimates. Coverage estimates for sulphide-oxidizing bacteria were strongly correlated between the FF and DF orientations across all substrate types. The occurrence of OPC was limited to a single mixed-substrate site, which provided the strongest FF vs. DF relationship within this study. In contrast to sulphide-oxidizing bacteria, epifaunal abundance (count data) revealed strong relationships between camera orientations for fine sediments and mixed sediments and a weaker relationship observed for vertical rock wall environments. Similar observations occurred for estimates of both sessile (dominated by plumose anemones) and motile taxa guilds comprising the total epifaunal community. Weaker relationships associated with the rock wall substrate are likely due to alternating blackout periods experienced by each camera orientation as the ROV passes vertical or ledge habitat zones. Overall, a combination of FF and DF video orientations may provide more robust abundance estimates for settings that are characterized by various substrate grades and structural and/or mat-forming taxa.