Mielck, F.; Hass, H.C., and Betzler, C., 2014. High-resolution hydroacoustic seafloor classification of sandy environments in the German Wadden Sea.

The knowledge regarding the distribution of seabed environments in the North Sea is still fragmentary. Hydroacoustic devices can provide rapid and reliable information on the acoustic characteristics of the seafloor. Data of a typical, exclusively sandy and shallow investigation area located in the German Wadden Sea are here presented. The study area includes shallow sublittoral areas and deep channels. The acoustic ground discrimination system RoxAnn was used to measures backscatter intensities, which indicate roughness and hardness parameters of seafloor. Sidescan-sonar data provide acoustic images that are instrumental in seafloor characterization. For ground truthing, surface-sediment samples were collected. The results reveal surficial sediments that range from fine to coarse sand. Finer material is rather restricted to the shallow patches, while coarser sediments characterize the deeper tidal channels. The determined roughness and hardness parameters also strongly increase within these inlets following the change in grain size. The sidescan-sonar imagery shows flow-transverse subaqueous dunes of different sizes. Both ebb- and flood-dominated structures are present. RoxAnn reflects these zones of subaqueous dunes basically through the formation of distinct clusters of data points in hardness vs. roughness scatter plots. Further, the results show that areas characterized by similar grain-size spectra and sonar imagery occasionally reveal completely different roughness and hardness properties. This is caused by varying amounts of shell fragments on the seafloor. Both in situ and hydroacoustic methods are suitable for identifying seafloor properties, but the combination of methods yields more information at higher precision, especially about shell content and grain-size distribution.

Silva, J.B.; Duleba, W.; Sallun, A.M., and Suguio, K., 2014. Benthic foraminifera as evidence of paleoenvironmental changes between 9400 and 8300 cal YBP at the Juréia-Itatins Ecological Station paleolagoon (SP, Brasil).

Many aspects of the Santos Transgression (∼21,227–20,448 to ∼5558–4558 cal YBP) remain controversial, especially before approximately 7800 cal YBP, because of the paucity of data for the Brazilian coast. In this context, benthic foraminiferal assemblages from between 9400 and 8385 cal YBP were analyzed from the S03 core collected at the Juréia-Itatins Ecological Station (JIES) with the aim of clarifying the behavior of the relative sea level along the Brazilian coast during this period. Microfaunal, taphonomical, and morphometric analyses of these microorganisms permitted recognition of eight paleoenvironmental conditions within the lagoon then existing at JIES. There were four phases of conspicuous marine contributions (9400–9338, 9072–8894, 8656–8641, and 8594–8500 cal YBP) with a climax at 8656 cal YBP, when the environment became more favorable to the growth, preservation, or both of benthic foraminifera. They were intercalated with two phases of prominent continental contributions (9338–9072 and 8500–8385 cal YBP), when there was an increase in the local hydrodynamic gradient at the S03 core sampling site. Furthermore, between 8806 and 8672 cal YBP and between 8625 and 8594 cal YBP, the benthic foraminifera are absent, most likely because of the lower pH of the mixohaline/limnetic waters present when the continental contribution was highest. These different phases of marine and continental contributions could be explained by the higher or lower inflow of seawater to the paleolagoon of the JIES and by changes of the regional rainfall.

Muitos aspectos da Transgressão Santos (∼21.227–20.448 a ∼5558–4558 anos cal AP) são ainda controvertidos, especialmente antes de aproximadamente 7800 anos cal AP, devido à diferença de detalhamento de dados na costa brasileira. Nesse contexto, foram analisadas associações de foraminíferos bentônicos no testemunho S03, coletado na Estação Ecológica Juréia-Itatins (EEJI), entre 9400 e 8385 anos cal AP, para colaborar com o conhecimento acerca do nível relativo do mar na costa brasileira sudeste durante esse período. As análises microfaunísticas, tafonômicas, e morfométricas das testas e associações desses microorganismos permitiram a determinação de oito fases distintas nas condições paleoambientais na laguna então existente na EEJI. Houve quatro fases de contribuição oceânica mais conspícua (9400–9338, 9072–8894, 8656–8641, e 8594–8500 anos cal AP) com clímax há 8656 anos cal AP, quando o ambiente se tornou mais favorável ao crescimento, à preservação, ou ambos dos foraminíferos bentônicos. Elas foram entrecortadas por duas fases de contribuição continental proeminente (9338–9072 e 8500–8385 anos cal AP), quando houve aumento do gradiente hidrodinâmico local no local de coleta do testemunho S03. Além disso, entre 8806 e 8672 anos cal AP e entre 8625 e 8594 anos cal AP, os foraminíferos bentônicos estiveram ausentes, muito provavelmente devido ao menor pH das águas oligohalinas/limnéticas presentes quando a contribuição continental à paleolagoa da EEJI foi maior. Essas diferentes contribuições podem estar vinculadas a modificações da pluviosidade regional e a diferenças no comportamento marinho durante sua fase transgressiva.

Tuominen, J. and Lipping, T., 2014. Feasibility of benthic cover-type mapping in turbid waters near estuaries using hyperspectral remote sensing.

In this study the feasibility of benthic cover-type mapping in turbid waters near estuaries using hyperspectral remote sensing is explored. The majority of research papers addressing remote sensing of benthic cover types concentrate on optically clear, shallow coastal and reef waters. In order to study the effects of water depth and water quality on benthic cover-type classification, a synthetic data set was generated. Synthetic spectra were calculated using in situ optical measurements of water quality and spectra of different bottom types. The data set was classified using the spectral correlation mapper (SCM) and the Euclidean distance (ED) classifier. A simple water-column correction method was also tested. The overall mapping accuracy of SCM classification without water-column correction reached 47.8% when the depth range 0.0–3.0 m was studied. The mapping accuracy increased to 66.0% using the ED classifier with water-column correction. When water quality was changed from least turbid to most turbid, the overall accuracy decreased to 50.4%.

Morang, A.; Waters, J.P., and Stauble, D.K., 2014. Performance of submerged prefabricated structures to improve sand retention at beach nourishment projects.

Submerged breakwaters were examined to evaluate their performance in maintaining the natural beach and retaining beach fill. These included sites where prefabricated concrete reefs, sills, and ball-like reef structures had been deployed. Most of these innovative structures have not performed well in exposed, open-coast, settings unless they were mounted on hard bottom. The Cape May Point, New Jersey, Section 227 demonstration site was used to develop a conceptual analysis model. The project monitored the functional, structural, and economic performance of two innovative prefabricated concrete structures placed at the seaward end of a groin compartment to form an enclosed sill. The project was conducted in conjunction with an ecosystem restoration beach fill to assess if a Beachsaver Reef™ and a Double-T sill could help to hold fill sediment in place at the entrance to Delaware Bay, which is influenced by high wave energy and strong tidal currents. The Beachsaver Reef™ units appear to be retaining the fill sand, while the Double-T sill settled completely into the bed and is no longer functioning as intended. Settlement and scour of these prefabricated units present the most problems in project performance. Wave attenuation performance is poor when the units settle, and they are better suited to act as a sill to hold sediment on a beach. Guidance is provided from the conceptual model at Cape May Point on the components that are needed to monitor a successful project. Criteria are given on how to evaluate project performance.

Hippensteel, S.P. and Garcia, W.J., 2014. Micropaleontological evidence of prehistoric hurricane strikes from southeastern North Carolina.

Nine back barrier marshes from Onslow Bay, North Carolina, were cored to a 3-m depth in search of paleohurricane deposits. Only two marshes, Alligator Bay and Tar Landing Bay, contained sand layers enriched with displaced marine foraminifers indicative of storm deposition. Ten discrete storm layers, representing four storms, were recovered at Tar Landing Bay, and 16 storm deposits, representing five storms, were recovered at Alligator Bay. Radiocarbon analysis indicates these storm layers were all deposited during the last 1500 years. Foraminiferal assemblages from the sediments directly below the coarser-grained storm layers indicate that the paleostorms were depositing marine and beach/dune sediment into a variety of marsh subenvironments and that preservation was not necessarily greater in the high marsh (lower bioturbation) subenvironment. Onslow Bay has sustained more than 10 hurricane strikes in the last 200 years. The scarcity of storm deposits detected in the strata from these nine marshes (representing approximately 1500 years of deposition) suggests that sand layers enriched with displaced marine foraminifers may significantly underestimate the frequency of storms in the region and may be limited as a paleotempest proxy. The preserved storm layers probably represent only the largest, most robust storm deposits from intense hurricanes.

Mull, J. and Ruggiero, P., 2014. Estimating storm-induced dune erosion and overtopping along U.S. West Coast beaches.

Coastal foredunes protect lives, infrastructure, and ecosystems during severe storms. A range of approaches, ranging from simple (e.g., geometric) to complex (e.g., process based) predictive models, have been developed to quantify overtopping and foredune retreat during storms. At present, however, there is no widely accepted approach for assessing the vulnerability of coastal foredunes to erosion and overtopping hazards. Because different coastal regions have distinct storm and geomorphic characteristics, models need to be assessed and possibly adapted before they can be successfully applied to each unique region. In this study we apply a total water level (TWL) model and three simple foredune erosion models and assess their suitability for U.S. West Coast vulnerability analyses. The erosion models include a geometric model, an equilibrium profile model, and a wave impact model. We discuss the assumptions required to implement each model and force them with hydrodynamic conditions associated with a large-scale laboratory dune erosion experiment and a major winter storm approximately equivalent to the 30 year return period (TWL) event in the U.S. Pacific Northwest. The models are each applied with beach and foredune characteristics extracted from airborne topographic LiDAR (light detection and ranging) data collected along the coasts of Oregon and Washington. Sensitivity tests reveal distinct differences in model dependence on beach slope, a critical parameter in determining storm water level elevations and ultimately the extent of foredune retreat. Without detailed, reliable field observations of storm-induced dune erosion from the region, the accuracy of each model is determined using results of the dune erosion experiment. Estimates of both overtopping and erosion extent are normalized by foredune dimensions, enabling comparisons of relative vulnerability between different reaches of coast.

Kwon, B.-O.; Koh, C.-H.; Khim. J. S.; Park, J.; Kang, S-G., and Hwang, J.H., 2014. The relationship between primary production of microphytobenthos and tidal cycle on the Hwaseong mudflat, west coast of Korea.

The present study examined variation in sediment temperature and irradiance with respect to microphytobenthos primary production at the Hwaseong mudflat, west coast of Korea, under different tidal cycles. The study was carried out during March and April 2009, which encompassed two spring tides and one neap tide. It was not possible to continuously measure primary production in situ across the tidal cycles; hence, photosynthesis–irradiance (P-I) curves at different temperatures were obtained experimentally in the laboratory. These readings were then used to calculate primary production, by projecting in situ mooring records of irradiance and temperature onto the P-I curves. The sediment temperature and irradiance were measured continuously, and the averages of 10-minute intervals from the mooring records were used. The results show that changes in primary production simulated from the P-I curves were strongly associated with the tidal cycle. During the two spring tides that were recorded, mean daily primary production was 1005 and 1125 mg C m⁻² d⁻¹, respectively. However, primary production was lower during the neap tide (898 mg C m⁻² d⁻¹). Temperature appeared to influence these differences in mean daily production. In situ mean daily temperatures during exposure were 14°C and 20°C during the first and second spring tides, respectively. In contrast, mean daily total irradiance was noticeably higher in the first spring tide compared with the second spring tide. During the neap tide, the site was exposed in the morning and afternoon, when light intensity and temperature were relatively low. In contrast, during the spring tide, the site was exposed at noon, when light intensity and temperature were high. The current study provided new insights about how changes in environmental parameters during tidal cycles affect microphytobenthic primary production, indicating the complexity of this process and the requirement for further fine-scale research.

Barboza, C.D.N.; Paes, E.T.; Jandre, K.A., and Marques, Jr., A.N., 2014. Concentrations and fluxes of nutrients and suspended organic matter in a tropical estuarine system: The Tinharé-Boipeba Islands Archipelago (Baixo Sul Baiano, Brazil).

Variations in the concentrations and fluxes of nutrients and suspended organic matter were examined during tidal cycles in four sectors (Barra dos Carvalhos, Barra de Boipeba, Cairu, and Galeão) of the estuarine system of the Tinharé-Boipeba Islands Archipelago (ESTBIA) on the northeastern Brazilian coast. In this study, we obtained new data by sampling and also used data from the literature (for Galeão) to estimate the exchange of nutrients between the estuary and the adjacent sea and to evaluate the factors that control these fluxes. It was observed that the factors that most influenced the nutrient fluxes in the estuarine system were the variations in the tidal prism and in the fluviometric regime. Moreover, the highest concentrations of dissolved inorganic nutrients occurred during the neap tide cycle, whereas the highest concentrations of particulates were found in the spring cycle. Organic carbon was transported in greater amounts in the dissolved form than in the particulate form, whereas nitrogen occurred predominantly in the organic form. The C : N and C : P ratios of the particulate organic material were typically high, showing a certain degree of seasonality related to the level of flooding of the mangroves. The nutrient fluxes transported in each sector showed the following tendency: Galeão ≥ Cairu >> Barra dos Carvalhos >> Barra de Boipeba. The net budgets for water and nutrients obtained for Galeão always reflected export from the estuary. In the other regions, particulate organic carbon, NO , NO , and NH were also exported from the estuary, whereas the remaining nutrients were exported during the neap tide cycle and imported during the spring cycle.

Mallinger, R., 2014. Dune vegetation and insect communities vary with barrier beach geomorphic setting on Sapelo Island, USA.

Coastal geomorphic processes, including shore disturbance events, shape coastal landforms and sand dune ecosystems. The magnitude and frequency of shore disturbance can affect dune vegetation diversity, community composition, and succession. Furthermore, these processes might impact higher trophic levels, such as insects, either directly or indirectly through changes in dune vegetation. The objective of this study was to characterize differences in vegetation and insect communities along sand dunes varying in geomorphic setting and exposure to shore disturbance. Vegetation and insects were sampled along Nannygoat Beach, Sapelo Island, Georgia, United States, in areas historically documented to differ in erosion rates and in exposure to storm surges and overwash. Dune height and beach berm width were measured to describe geomorphic setting. The north end of Nannygoat Beach had taller sand dunes and a shorter beach berm width, indicating less overwash but greater rates of erosion compared to the south end. Plant diversity was significantly greater on the north end of Nannygoat, while insect richness was significantly greater on the south end of Nannygoat beach. Both plant and insect community composition were significantly different between the north and south ends of the beach. Furthermore, the plant community composition was significantly related to the abiotic variables, while the insect community composition was significantly related to the plant community. These results suggest that vegetation communities of barrier islands are strongly influenced by geomorphic processes, while insect communities are, in turn, shaped by the vegetation communities.

Dai, Z.-j.; Liu, J.T.; Xie H.-l., and Shi, W.-y., 2014. Sedimentation in the outer Hangzhou Bay, China: The influence of Changjiang sediment load.

Most estuaries in the world are facing the risk of subsidence due to insufficient sediment supply and relative sea-level rise. In the case of the world's fourth largest river, the Changjiang (aka Yangtze River), its river sediment load has been decreasing sharply, especially since the construction of the Three Gorges Dam. Due to the complexity in the estuarine dynamics, human activities, and the sediment supply, discerning whether the Changjiang Estuary is facing erosion or subsidence is a controversial issue. Immediately south of the mouth of the Changjiang is Hangzhou Bay. On the centennial time scale, accretion on the southern flank of the Changjiang deltaic plain has caused the seaward extension of the north bank of the Qiantang Estuary, leading to the formation of the macrotidal, funnel-shaped Hangzhou Bay. In this study, we used multiyear geographic information system (GIS)–rectified bathymetric charts of Hangzhou Bay for bathymetry and sediment-capacity change analysis. Our major findings show that the outer Hangzhou Bay has gone through the following stages: relatively steady sedimentation (1931–1997), erosional-depositional transition (1997–2002), and rapid erosion (2002–2008) at the rate of 58.5 × 10⁶ m³/y. Our findings also corroborate measurements of suspended sediment discharge at the Datong station in the lower reaches of the Changjiang. Our findings confirm the dependence of the sedimentation in the outer Hangzhou Bay on the sediment supplied by the Changjiang. The severity of the erosion of the outer Hangzhou Bay and the sediment load decrease of the Changjiang might serve as a warning for the impending erosion of the Changjiang Estuary.

Pan, J. and Marcoval, M.A., 2014. Top-down effects of an exotic serpulid polychaete on natural plankton assemblage of estuarine and brackish systems in the SW Atlantic.

The invasive reef-building polychaete Ficopomatus enigmaticus (Fauvel, 1923) has become well-established in many temperate brackish waters. To analyze preferences for different planktonic food sources, short-term (∼1.5 h), grazing microcosm experiments were performed in situ (n = 3), at two water bodies, a coastal lagoon (Mar Chiquita, MC) and the mixohaline stretches of a coastal creek (La Tigra, LT), Argentina, in January 2007. Relative clearance rates of phytoplankton were assessed for chlorophyll a size-fractions and for different groups of nanoplanktonic and microplanktonic protists. The two locations showed significant differences in plankton community structure. Nanoeukaryotes were the dominant group at both locations; the second most-abundant groups were diatoms at MC and ciliates at LT. There were significant differences in chlorophyll-based clearance rates in relation to phytoplankton size-fraction. Clearance rates for pennate diatoms were significantly higher than for any other planktonic prey (2.3 l h⁻¹ g DW⁻¹). Ficopomatus enigmaticus presented relatively high clearance rates for heterotrophic ciliates (1.5 l h⁻¹ g DW⁻¹). Biomass removal by F. enigmaticus was high (>50% of initial standing stocks for all components), indicating that the serpulid was capable of regulating planktonic biomass. Significant differences in clearance for different components of the community suggest that F. enigmaticus has the potential to promote changes in plankton community structure and, hence, exerts strong top-down controls.

Kakroodi, A.A.; Kroonenberg, S.B., and Naderi Bonab, M. 2014. Short- and long-term development of the Miankaleh Spit, southeast Caspian Sea, Iran.

The development of the 60-km-long Miankaleh Spit in the southeastern corner of the Caspian Sea has been studied in two different timescales. At the start of the twentieth century 3 m sea-level cycle, the spit already existed, but it emerged prominently during the lowstand in the late 1970s, and drowned and fell apart into several islands during the following highstand that culminated in 1995. The analysis of core data and sedimentological analyses (grain size, biofacies, carbonate content, heavy mineral, and magnetic susceptibility) show that the Miankaleh Spit and the Gorgan Bay did not yet exist during the well-known 2600–2300 cal. YBP highstand, and at that time waves and longshore currents deposited barrier systems along the mainland coast. During the lowstand, deltas from rivers draining the eastern Alborz Mountains extended much more westward than at present. It was only during the last major highstand in the Little Ice Age that the present-day Miankaleh Spit was formed by eastward progradation caused by strong longshore currents.

Kakroodi, A.A.; Kroonenberg, S.B.; Goorabi, A., and Yamani, M., 2014. Shoreline response to rapid 20th century sea-level change along the Iranian Caspian Coast.

The Caspian Sea, the largest lake in the world, is characterized by rapid sea-level changes. This provides a real physical model of coastal response to rapid sea-level change in a period of just a few years, which might take a millennium along oceanic coasts. Between 1929 and 1995, the Caspian sea level experienced the last cycle, with a range of ±3 m. This caused disastrous effects along the coast and destroyed many buildings, roads, farms, and other human property. During the preceding 48 years of sea-level fall, a large area of the sea bottom emerged, which was then used for the development of residential zones. That area had to be abandoned when sea level rose by almost 3 m in a period of 18 years. With the use of LANDSAT data, we calculated total shoreline shifts in 22 littoral cells, each cell containing three transects over a 3-km distance. Both landward and seaward shifts occur during rapid sea-level rise between 1977 and 2001.

Hwang, S.W.; Lee, H.G.; Choi, K.H.; Kim, C.K., and Lee, T.W., 2014. Impact of sand extraction on fish assemblages in Gyeonggi Bay, Korea

During 2006 and 2007, 35.0 × 10⁶ m³ of marine sand was extracted by the construction industry from Gyeonggi Bay, which is an area within the coastal waters off the Taean District of Korea. The goal of our study was to compare the catches and assemblage structure of fish in this sand mining area (SMA) with those of two other nonmining areas (NMAs) in the bay. An otter trawl was used to obtain fish samples in each area. Both cluster analysis and nonmetric multidimensional scaling of the species composition in the sampled areas showed a higher similarity between the two NMAs than between the NMAs and the SMA. Furthermore, the SMA had significantly lower species richness (R1), species diversity (H′), and fish abundance compared with the two NMAs. These results could be associated with bottom disturbance related to the mining of seabed sediments. In conclusion, we confirm that sand mining processes directly influence the Gyeonggi Bay sea floor ecosystem and have a continuous effect on the assemblage of fish in this ecosystem.

Kaiser, M.F., 2014. Disturbance of hydrodynamic regime in the Mediterranean coastal zone of Egypt.

Engineering structures induce variations in the physical parameters of incident waves approaching coastlines, affecting the rate of longshore sediment transport and the patterns of shoreline change. Landsat Thematic Mapper images acquired from 1990 to 2005 and field measurements were utilized to perform mathematical modeling along Mediterranean coastal zones in Egypt. The K₁ transport coefficient values used to calibrate the models ranged from 0.05 to 0.9. To accommodate changes in the physical conditions, a second calibration was required. The K₁ transport coefficient values determined by the second calibration ranged from 0.1 to 0.7. These results indicate that the hydrodynamic regime along the Nile Delta coastal zones during 1995–2000 (verification) and 2000–2005 (second calibration) was disturbed by the effect of engineering works. Therefore, the calibration parameters used in simulations before 1995 are not appropriate for use after 1995. These findings demonstrate how the physical parameters of waves and currents are disturbed after some protective structures are modified.

Marujo, N.R.C.S.; Araújo, M.A.V.C., Trigo-Teixeira, A.; Falcão, A.P., and Mazzolari, A., 2014. Storm-surge hindcast at Viana do Castelo: An oceanic and estuarine domain approach.

In the present work a storm-surge event, which occurred in Viana do Castelo (Portugal) on 14–17 October 1987, is modelled using the advanced circulation model (ADCIRC) . The main purpose of the work is to investigate the ability of ADCIRC to model storm-surge events in the region. Modelling this type of phenomena is of the utmost importance to comply with the European Union directive 2007/60/CE, concerning the assessment and risk management of floods, and to create risk charts used in coastal zone management. During this process, a strong emphasis was given to model calibration before storm-surge modelling. Preceding model calibration a field survey, using global navigation satellite system techniques, was carried out in the Lima Estuary to acquire lacking information required to build the corresponding digital terrain model (DTM). While modelling storm surge, two different domains were considered: a large oceanic and a smaller estuarine. For each of these domains, the model was calibrated with astronomy forcing using, respectively, the 6 and 10 most important tidal constituents, which were determined by harmonic analysis of the Viana do Castelo tidal gauge record. The friction coefficient, wave continuity, and lateral viscosity parameters were changed with this aim. Although the friction coefficient proved to be the most important calibration parameter, the other parameters are also important to achieve stable simulations. For the oceanic domain, the obtained results were improved by considering a variable Coriolis factor. Once the model was calibrated, it was forced using astronomy and meteorology jointly and separately. Atmospheric pressure, wind, and, for the estuarine domain, also river flow were considered as meteorological agents. The storm event was satisfactorily reproduced by the model and it was concluded that meteorology and astronomical effects interact nonlinearly. This nonlinearity is more pronounced when considering the river flow due to the tidal wave–current interaction.

Jeong, Y.H.; Yang, J.S., and Park, K., 2014. Changes in water quality after the construction of an estuary dam in the Geum River Estuary Dam system, Korea.

We investigated long-term (1985–2009) changes in water quality due to the construction of an estuary dam in the Geum River Estuary Dam System, Korea. Both the upstream reservoir and downstream estuarine sides of the dam were examined. Water quality conditions for nutrients and chlorophyll a (Chl-a) have deteriorated considerably since the dam construction in 1994, with the reservoir water damaged more severely than the estuarine water. Improved water clarity and an enhanced level of nutrients resulted in an order of magnitude increase in Chl-a, indicating excessive phytoplankton growth in the reservoir after dam construction. The hydrology-related principal component (precipitation and discharge) was the most important and the autochthonous primary production-related principal component (nutrients and Chl-a) was the second most important factors affecting the postdam water quality conditions in both the reservoir and estuary. The cumulative load difference analysis revealed that the reservoir was a sink site for and as well as a source site for Chl-a owing to excessive phytoplankton growth in the reservoir. The discharge from the reservoir dominated the estuarine water quality during wet seasons.

Schiller, R.V. and Kourafalou, V.H., 2014. Loop current impact on the transport of Mississippi river waters.

River plume studies have traditionally focused on coastal and shelf circulation. Here, we examine novel interactions of a large river plume with offshore flows, which introduces additional export pathways for the riverine waters. We show the impact of the Loop Current System (LCS) on the offshore transport and fate of Mississippi River (MR) plume waters. The high-resolution Northern Gulf of Mexico (NGoM) model, nested in a data-assimilative, regional, Gulf of Mexico model, was employed for a 5-year, realistically forced simulation. Model results, in tandem with satellite data, demonstrate that the entrainment of MR waters by the LCS varies interannually and extends pathways of shelf cross-marginal transport to the basin interior and beyond. Plume-to-LCS interactions are determined by episodic northward intrusions of the LCS in the NGoM. If the intrusion is very close to the MR Delta, plume waters can be entrained with little contribution from winds. If the intrusion is farther offshore and lasts for months, LCS entrainment may be modulated by wind forcing because plume transport can change from an along-shelf to an exclusively across-shelf regime. Seasonal changes in river discharge did not have a direct influence on the transport induced by LCS intrusions. However, high-frequency (daily) variability of the river discharge induced by the Mississippi and 16 other major rivers was important and played a role in the overall NGoM freshwater transport. During the 5-year period, plume-to-LCS interactions corresponded on average to ∼11% of the yearly net offshore freshwater transport near the MR Delta. Model results were supported by satellite and in situ observations that demonstrate the far-reaching potential of MR waters as they are traced to the SE Gulf of Mexico and the Florida Keys. This study demonstrates how across-basin, connectivity pathways for riverine waters may be affected by local coastal-to-offshore interactions induced by a large-scale current system.

Xie, Z.; Ma, Z., and Liu, J., 2014. Conflicts in land use in marine protected areas: The case of the Yellow River Delta, China.

Marine protected areas (MPAs) play an important role in ecosystem service and resource management practices. Conflicts in Yellow River Delta protected areas (YRDPA) have arisen as a result of unpredictable natural hazards and unreasonable anthropogenic activities. The study applied remote sensing images and environmental and socioeconomic data to analyze the change of land use and land cover in YRDPA and to identify the driving forces for these changes from 1986 to 2010. The results show that land use has changed significantly over this period. The study analyzed the main conflict types, such as land use conflict, oil field exploration and wetland protection conflict, management conflict, and environmental conflict. The framework of conflict resolution is also presented, and resolution rules of sustainability, effectiveness, and adaptation are provided to mitigate conflicts to achieve coordinated marine management goals. The purpose of the study is to demonstrate the causes and impacts of conflicts and to identify conflict resolution strategies for marine protected areas management.

Kumar, P.K.D.; Gopinath, G.; Murali, R.M., and Muraleedharan, K.R., 2014. Geospatial analysis of long-term morphological changes in Cochin estuary, SW coast of India.

The Cochin estuary along the SW coast of India has undergone tremendous environmental changes due to continuous alterations. Geospatial information available since 1967 has been compiled to evaluate the long-term morphological changes. Quantification of geomorphological changes that occurred over the decades was made to have an integrated profile to ascertain the changes in the extent. Toposheet maps (1967) and satellite imageries for 2004 and 2011 have been interpreted. Quantitative comparison of inner island segments showed significant changes in island widths through time. It was found that the areas covered by the islands within the estuary during 1967, 2004, and 2011 were 81.62, 89.26, and 89.52 km², respectively, and those covered by the water body were 130.68, 121.3, and 118.01 km², respectively. The shrinking rate of the estuarine system was estimated to be 0.288 km²/y. About 11 km² of island area was found to be prograded, and 3 km² was eroded. In effect, the reduction in the aerial extent of the estuarine system was estimated to be 12.67 km². The evolution of the western estuary margin has been characterized by a strong progradation during the past 4 decades. The results obtained conclusively show that the estuary is being inflicted with major geomorphic changes at several segments, resulting in reduction in the extent. Geomorphic differences may lead to factors in modifying estuarine flows, which ultimately affect the dynamic processes within the estuary. Observed trends of morphological changes generate concern in the background that the region may continue to remain vulnerable in the coming decades due to development pressures in the adjoining hinterlands.

Richards, R.; Chaloupka, M.; Strauss, D., and Tomlinson, R., 2014. Using generalized additive modelling to understand the drivers of long-term nutrient dynamics in the Broadwater Estuary (a subtropical estuary), Gold Coast, Australia.

Conclusions drawn from comparing short-term monitoring data with a baseline data set and water-quality guidelines need to be viewed in the context of numerous physical and biogeochemical mechanisms controlling nutrient concentrations within a system over long timescales. This paper highlights the use of generalized additive models (GAMs) to explore the functional relationships between four commonly used water-quality indicators (total nitrogen, total phosphorous, ammonia, nitrate) and a range of drivers including catchment inflow, wind speed, and tidal current. The results of this GAM assessment highlighted that nutrient concentrations within a subtropical estuary (Broadwater, Australia) is most dependent on catchment inflow. In particular, this assessment indicated the apparent importance of the Nerang River as a determinant of the nutrient concentrations observed in the Broadwater compared with the role of other tributaries, even though these other rivers provide the bulk of the freshwater flow into the system. This assessment also highlighted that the potential effects of monitoring location, tides, wind, and monitoring year need to be accounted for when framing the results of short-term data.

Turner, R.E., 2014. Discussion of: Olea, R.A. and Coleman, J.L., Jr., 2014. A synoptic examination of causes of land loss in southern Louisiana as related to the exploitation of subsurface geological resources. Journal of Coastal Research, 30(5), 1025–1044.

I comment on Olea and Coleman's (2014) conclusion that subsidence was the primary cause of the dramatic rise in Louisiana's coastal land losses in the last 100 years. The focus on subsidence combined with the omission of context for factors not related to subsidence (e.g., dredged canals), leaves the reader with the incorrect conclusion that anthropogenic factors observed to date are insignificant, and that coastal wetland losses are only driven by subsidence. I address this omission by discussing two points about anthropogenic influences: (1) dredged canals and (2) changes in sediment load from the watershed and its distribution. They omit quantitative inclusion of two signature symptoms of the cause-and-effect relationships at temporal and spatial scales. To whit, there are: direct relationships between canal density and land loss over decades and shorter intervals for the whole coast and individual estuaries, instances of indirect losses immediately after canal construction, an increase in ponding near dredged canals but not further away, and, evidence of effective hydrologic barriers created by the spoil bank above- and belowground. The view that geological subsidence exerts a top-down control on the net adjustment to changes in vertical space leads to the narrow view of restoration being modeled using the mineral soils for wetland soils comprised mostly of organics. Further, the decline in suspended sediment concentrations since the 1950s (from dam construction) needs to be put within the context of the landscape changes occurring when European colonization resulted in much higher rates of erosion. The restriction of exclusively geological factors driving land loss is, therefore, an incomplete view of what causes land loss in modern times—and a perhaps dangerously naïve basis for management decisions on this coast. I agree with their conclusions that (1) geological subsidence has not changed significantly in the last 100 years, (2) fluid withdrawal is an unlikely and unproven large enough force to cause the patterns in land loss across the deltaic plain, and (3) acceleration in sea level rise will rise to problematic levels in the near future.