Middle Coast Research Articles

Genetic Diversity and Profile of Red Algae Pterocladiella capillacea (Gelidiales, Rhodophyta) along the Coast of China

Red algae Pterocladiella capillacea off the coast of China were investigated for genetic diversity. With 176 samples categorized into six populations based on concatenated rbcL and cox1 sequences, the results rang warning bells for the genetic diversity of Pterocladiella capillacea along the Chinese coastline: (1) a good diversity of haplotype (Hd > 0.5) in Naozhou and Hui’an populations situated along the southern coast of China, but highest in the former; (2) less nucleotide diversity in each of the six populations (Pi < 0.005); (3) genetic differentiation occurred between the north population in Changdao and the two southern grown populations in Nan’ao, and Naozhou. To identify molecular markers, an MP phylogenetic tree was used to illustrate genetic profiles in detail, with 161 concatenated sequences clustered into four branches: Changdao (north), Nan’ao (south), Naozhou (south), and the remaining regions (middle). The Fst value for each of Changdao, Nan’ao, and Naozhou was greater than 0.5, which denotes that these three populations are genetically different to those growing in the middle coast. Moreover, a 30-haplotype-based median-joining network corroborated this genetic differentiation, though variations between all the investigated populations were not very high due to the relatively smaller values of genetic distance between the six (Dxy < 0.01). Overall, red algae P. capillacea in Chinese coastal seawater showed a higher haplotype diversity and lower nucleotide diversity. Such a genetic profile indicates that both natural random genetic drift and interference from human activities have possibly affected the distribution of gene frequencies in red algae P. capillacea along the Chinese coastline.

Assessment of spawning and nursery habitats of hilsa in the Tetulia and Meghna river estuaries

The Meghna River estuary (MRE) and Tetulia River estuary (TRE) are tropical estuaries on the middle coast of Bangladesh. Hilsa shad (Tenualosa ilisha), is one of the most important anadromous fish (ascending rivers from the sea for breeding), migrates into the Meghna and Tetulia River estuarine systems from the Bay of Bengal. This study assessed the spawning and nursery habitats of hilsa in the Tetulia and Meghna River estuaries by examining the environmental parameters of both estuarine ecosystems. Water samples were collected from nineteen selected sampling sites along and across the estuaries from January to December 2021 covering both the dry and wet seasons. Salinity, dissolved inorganic nitrogen (DIN), and dissolved inorganic phosphorus (DIP) concentration varied significantly (p < 0.05) between the MRE and TRE during the dry season. In contrast, no significant variation (p > 0.05) was observed in the salinity, DIN and DIP between the MRE and TRE during the wet season. In addition, no significant variation (p > 0.05) was observed in chlorophyll-a concentration between the MRE and TRE during the dry and wet seasons. The salinity tolerance range is an important driver for the spawning (salinity <0.1 psu) and nursery (salinity <0~2 psu) habitat of hilsa. This study explored that the TRE is suitable for spawning and nursery habitat (salinity <0.09 psu) for hilsa all year round because the TRE acts as a freshwater ecosystem (salinity <0.1 psu) annually. Therefore, the government should focus on protecting and conserving juvenile hilsa (jatka) and brood hilsa in the TRE year round. Ann. Bangladesh Agric. (2023) 27 (1): 57-69

The Evaluation of MII/SDGSAT-1 in Red Tide Detection Along the Guangdong Middle Coast

The Evaluation of MII/SDGSAT-1 in Red Tide Detection Along the Guangdong Middle Coast

Plastic Pellets in the Sandy Sediment of Beaches on the Middle Coast of Rio Grande do Sul, Brazil

Purpose: Pellets are plastic granules used in the industry to manufacture many materials and can be lost to the environment throughout the production chain. This study evaluated the number of pellets on beaches, on the middle coast of the state of Rio Grande do Sul, a region with low urban agglomeration, and few studies on this topic. The quantity found in relation to the distance from the port of Rio Grande was also evaluated. Method: The collection of sandy sediment occurred in three seasons of the year and, for each beach, quadrants were sampled at the mark of the last high tide Results and conclusion: 96.26% of the pellets were collected in spring, 3.74% in autumn, and none in summer. Storm events and large amounts of organic matter may explain the result in spring, while strong winds may have influenced the summer collection. The results found did not show a direct relationship with the distance from the Port, since there was no well-defined distribution pattern. Research implications: It is essential to map the loss of pellets in the environment, including in sparsely urbanized areas. Pellets can be lost during transport at sea, where currents and winds can carry them to different regions. Therefore, control and management measures for losses of these materials are necessary. Originality/value: The work is unprecedented and maps pollution by plastic pellets on beaches with little anthropogenic activity in Rio Grande do Sul. The results indicate that is important an integrate coastal management.

Determining spatiotemporal trends in hatch and metamorphosis timing of young-of-year southern flounder Paralichthys lethostigma) in Texas bays

It is important to monitor spatiotemporal shifts in the timing of key life history events (i.e., hatch and metamorphosis) since these can influence larval survival and juvenile recruitment success. We use otolith microstructure analysis to examine spatiotemporal trends in hatch and metamorphosis timing of a widespread and economically-valuable finfish, southern flounder Paralichthys lethostigma, in Texas. We use linear regressions that predict otolith-based age from length for young-of-year (YOY) individuals caught coastwide from 2019 to 2021 to calculate hatch and metamorphosis dates of YOY individuals caught coastwide across a 39-yr time series from 1980 to 2018. Also, we use YOY hatchery-reared individuals to indirectly validate the association between otolith accessory growth centers and larval metamorphosis. Our analysis reveals that on the middle coast average hatch timing is shifting toward earlier in the year across the 39-yr time series. In contrast, we find that coastwide, and especially on the middle coast, average metamorphosis timing is shifting toward later in the year across the 39-yr time series. On average, YOY individuals show similar hatch and metamorphosis timing coastwide. We find that on the middle coast and across the 39-yr time series, higher maximum water temperature correlates with earlier average hatch timing. In contrast, we find that coastwide, and especially on the lower and middle coast, higher average water temperature (later years in time series) correlates with later average metamorphosis timing across the 39-yr time series. Fishery-independent monitoring shows no concurrent evidence of individuals emigrating earlier in the fall to spawn offshore. We interpret the spatiotemporal trends in average hatch and metamorphosis timing as evidence of a narrowing survival window where (1) individuals caught on the middle coast that hatch earlier experience higher survival during years with higher maximum water temperature and (2) individuals caught coastwide that metamorphose later experience higher survival during years with higher average water temperature (later years in time series). We highlight the ecological and management implications of the impact of water temperature on hatch and metamorphosis timing and in turn, larval survival and juvenile recruitment success.

Intra‐annual variation in activity budgets of a wild Chilean Flamingo (Phoenicopterus chilensis) population in Southern Brazil

AbstractAssessing animal behaviour is essential for understanding their relationship with the environment and assisting in the management and conservation of species in natural habitats, especially those that present large range distribution and occupy very dynamic environments. The Chilean Flamingo (Phoenicopterus chilensis, Aves: Phoenicopteridae) breeds in the temperate regions of South America, going from Ecuador to the south of Argentina, but moves to regions on the southern coast of Brazil and Uruguay during the non‐breeding season. To understand activity patterns and behavioural variations on wild Chilean Flamingos in Brazil, we carried out monthly field trips to the Lagoa do Peixe National Park, on the middle coast of Rio Grande do Sul state, between May and November 2019, totalling 99.8 total hours of observation. Forty‐one different behaviours were detected, divided into six categories: Feeding, Locomotion, Resting, Preening, Social Agonist and Social Non‐Agonist. A significant variation in frequency, total duration and mean duration was detected for the behavioural categories over the months, mainly in the social categories, possibly indicating a strong influence of climatic aspects, such as temperature, rainfall and wind, but also of population aspects, such as flock density and stage of the reproductive cycle, in the behaviours observed in the lagoon. We also detected a variation in behavioural richness and active behaviours among the months, indicating that contranuptial areas like Lagoa do Peixe can be used for more than only feeding and resting.

Factors Influencing Dietary Changes of Walleye Pollock, Gadus chalcogrammus, Inhabiting the East Sea off the Korean Coast

This study examined the dietary patterns of walleye pollock, Gadus chalcogrammus, off the middle eastern coast of Korea between January 2016 and December 2017 to determine the influences of various predictors on dietary changes. Based on stomach content analyses, walleye pollock was found to be a demersal carnivore that mainly consumes carid shrimps, euphausiids, mysids, teleosts, and cephalopods. The main prey species identified in the diets of walleye pollock were Euphausia pacifica (euphausiids), Themisto japonicus (amphipods), Neomysis spp. (mysids), Neocrangon communis, Pandalus borealis (carid shrimps), Watasenia scintillans (cephalopods), and Bothrocara hollandi (teleosts), which are hyper-benthic and bentho-pelagic organisms. Dietary analyses based on the weight contributions of different prey taxa to the diets revealed significant variations in dietary composition in terms of fish size, water depth, and season, implying intraspecific dietary segregation. Euphausiids dominate the diets of smaller individuals (<30 cm TL), whereas the contributions of carid shrimps, teleosts, and cephalopods increase as body size increases. Similarly, the latter three prey items are dominant food resources in deeper habitats. The PERMANOVA results revealed that the size-related spatial and temporal changes in dietary composition are all significant for the species, as well as their two- or three-way interactions among those factors, except for the size-depth interaction. The coupling effect of size and depth is indicative of depth-dependent differences in fish sizes, with the tendency for larger individuals to be distributed in deeper habitats. In addition, seasonal and interannual variations in water column structures are also evident in the diets, which may, in part, account for the diet seasonality observed in the stomach content analysis. The dietary analyses of walleye pollock will improve our understandings to seek functional role of the species in benthic food webs, and to predict the effects of environmental and anthropogenic perturbations.

Mapping an Invasive Plant Spartina alterniflora by Combining an Ensemble One-Class Classification Algorithm with a Phenological NDVI Time-Series Analysis Approach in Middle Coast of Jiangsu, China

Spartina alterniflora (S. alterniflora) is one of the worst plant invaders in the coastal wetlands of China. Accurate and repeatable mapping of S. alterniflora invasion is essential to develop cost-effective management strategies for conserving native biodiversity. Traditional remote-sensing-based mapping methods require a lot of fieldwork for sample collection. Moreover, our ability to detect this invasive species is still limited because of poor spectral separability between S. alterniflora and its co-dominant native plants. Therefore, we proposed a novel scheme that uses an ensemble one-class classifier (EOCC) in combination with phenological Normalized Difference Vegetation Index (NDVI) time-series analysis (TSA) to detect S. alterniflora. We evaluated the performance of the EOCC algorithm in two scenarios, i.e., single-scene analysis (SSA) and NDVI-TSA in the core zones of Yancheng National Natural Reserve (YNNR). Meanwhile, a fully supervised classifier support vector machine (SVM) was tested in the two scenarios for comparison. With these scenarios, the crucial phenological stages and the advantage of phenological NDVI-TSA in S. alterniflora recognition were also investigated. Results indicated the EOCC using only positive training data performed similarly well with the SVM trained on complete training data in the YNNR. Moreover, the EOCC algorithm presented a more robust transferability with notably higher classification accuracy than the SVM when being transferred to a second site, without a second training. Furthermore, when combined with the phenological NDVI-TSA, the EOCC algorithm presented more balanced sensitivity–specificity result, showing slightly better transferability than it performed in the best phenological stage (i.e., senescence stage of November). The achieved results (overall accuracy (OA), Kappa, and true skill statistic (TSS) were 92.92%, 0.843, and 0.834 for the YNNR, and OA, Kappa, and TSS were 90.94%, 0.815, and 0.825 for transferability to the non-training site) suggest that our detection scheme has a high potential for the mapping of S. alterniflora across different areas, and the EOCC algorithm can be a viable alternative to traditional supervised classification method for invasive plant detection.

Heavy metal concentrations in tissues of marine fish and crab collected from the middle coast of Zhejiang Province, China.

Concentrations of the heavy metals As, Cd, Cu, Hg, Pb, and Zn in various tissues of five marine fish species and one crab species collected from the middle coast of Zhejiang Province of China were investigated in this study. The results indicated considerable variation in heavy metal concentrations in different tissues and species. Elevated concentrations of most heavy metals were identified in fish gills and crab gills and hepatopancreas, with some differences by heavy metal type. In addition, carnivorous and benthivorous fish species generally contained relatively high concentrations of heavy metals due to feeding habits and habitats. Geographical variations of heavy metal concentrations in muscle may be attributable to species-dependent differences and terrigenous contamination. The potential health risk assessment suggested that exposure doses of most heavy metals were safe for human consumption, with the exception of As.

Comparison of PAH Mass Concentrations in Aerosols of the Middle Adriatic Coast Area and Central Croatia

Polycyclic aromatic hydrocarbons (PAHs) are considered priority pollutants due to their distribution, persistence, bioaccumulation, and adverse effects on human health. The aim of this study was to obtain the first insight into PAHs mass concentrations bound to airborne particulate matter (PM) in the mid Adriatic coast area of Croatia, and compare them with the PAH levels in Croatia’s urban central area. Relatively low values of PAH mass concentrations were measured in the coastal area, compared to the continental urban region of Croatia impacted by increased emissions due to intensive traffic, industry, and residential heating. A high PM10 contribution of four-ring PAHs (Flu and Pyr) at Martinska site indicated that wood burning heating as well as open fire events, including waste incineration, could be important emission sources of PAHs in the mid Adriatic coast region.

Use of NDVI and Landscape Metrics to Assess Effects of Riverine Inputs on Wetland Productivity and Stability

Alterations to Louisiana’s river systems and local hydrology have resulted in reduced freshwater, sediment, and nutrient inputs to wetland landscapes, causing significant negative impacts on marsh productivity and stability. This study set out to assess regional- and basin-scale impacts of river connectivity and sediment availability on wetland productivity. Satellite data were used in conjunction with river discharge, river sediment concentration, and wetland accretion data to evaluate correlations between river connectivity and wetland productivity and stability. Significant correlations were observed between river connectivity and Normalized Difference Vegetation Index (NDVI) and Aggregation Index (AI) values across a 10 year period of analysis. Moderate correlations (r2 = 0.51) between mean NDVI and AI values were observed for all wetland vegetation in coastal Louisiana. Middle Coast wetlands had the highest river connectivity and significantly higher aboveground productivity, spatial integrity, and wetland area. The Chenier Plain, with moderate sediment and nutrient inputs, consisted primarily of moderate productivity and integrity. The majority of the inactive Deltaic Plain, which is largely sediment deprived, consists of landscapes with the lowest wetland productivity and spatial integrity. This study linked wetland area, configuration, and productivity with river connectivity to provide an enhanced understanding of river and sediment importance for wetland stability and restoration.

Diet composition of the small sandeel (Ammodytes tobianus) in the Polish part of the southern Baltic Sea

The aim of this survey was to determine the diet composition of the small sandeel (Ammodytes tobianus L.) from coastal waters of the middle coast of Poland. The small sandeel is a fish that is only occasionally caught on an industrial scale in the Polish exclusive economic zone, but it does constitute an important food source for predatory fish, seabirds, and mammals. This species throughout the whole life feeds mostly on zooplankton. The fish for the surveys came from manual trawl hauls carried out in various seasons of the year, between November 2014 and September 2015, in the region of the estuary of the river Łupawa to the southern Baltic Sea. The surveys involved both a macroscopic examination of the stomach fullness degree of the small sandeel and a detailed analysis of its diet composition. Studies results indicated that in the course of the year, over 60% of individuals of the small sandeel had their stomachs filled with food in August, while in the early spring and late autumn their stomachs were often empty. When the samples from all analyzed months were taken into account, the diet of the small sandeel varied and consisted of 26 food components. The basis of the diet was mainly made up of Calanoida: Acartia spp. and Temora longicornis. Moreover, freshwater Cyclopoida had a high frequency of occurrence in the diet of the small sandeel throughout the year of surveys, because as organisms typical for the Lake Gardno, through which the river Łupawa flows, they also occurred in the coastal waters. In May, Harpacticoida also appeared in all analyzed individuals of the small sandeel. Only the largest small sandeels fed on fish larvae and Mysidacea. The diet composition of the small sandeel confirmed that these fish are linked with a specific habitat and do not undertake long-distance food migrations.

Evaluation of Nutritional and Mineral-Heavy Metal Contents of Horse Mackerel (Trachurus trachurus) in the Middle Black Sea in terms of Human Health

In this study, the effects of seasonal and sexual differences on the nutritional composition, macro (Na, Mg, P, K, Ca), trace element (Mn, Fe, Co, Cu, Zn, Mo, Ni, Se) and potential toxic metal levels (Cd, Pb, As) of horse mackerel (Trachurus trachurus) caught in the middle Black Sea coast during all seasons were investigated. The metal levels of muscle tissues of the examined specimens were determined using ICP-MS instrument. The results showed that horse mackerel had a high nutritional value in terms of protein and lipid levels. Metal levels were found to be different in terms of sexual and seasonal factors. With regard to macro element levels, horse mackerel muscle was found to be rich. Zn and Cu levels of the trace elements were below the legal limits specified by the codex. It was also observed that the levels of Cd and Pb in horse mackerel muscle tissue were below the FAO (Food Agriculture Organ U N 464:5-10, 1983) limit values and above the TFC (Turkish Food Codex 2011) limit values. In terms of EWI and EDI values, horse mackerel was found to be non-toxic. This study suggests that horse mackerel is beneficial seafood for human health and nutrition.

Temporal dynamics of land use and cover in Paurá Lagoon region, Middle Coast of Rio Grande do Sul (RS), Brazil

Temporal dynamics of land use and cover in Paurá Lagoon region, Middle Coast of Rio Grande do Sul (RS), Brazil

Appling the One-Class Classification Method of Maxent to Detect an Invasive Plant Spartina alterniflora with Time-Series Analysis

Spartina alterniflora has become the main invasive plant along the Chinese coast and now threatens the local ecological environment. Accurately monitoring the distribution of S. alterniflora is urgent and essential for developing cost-effective control strategies. In this study, we applied the One-Class Classification (OCC) methods of Maximum entropy (Maxent) and Biased Support Vector Machine (BSVM) based on Landsat time-series imagery to detect the species on the middle coast of Jiangsu in east China. We conducted four experimental setups (i.e., single-scene analysis, time-series analysis, Normalized Difference Vegetation Index (NDVI) time-series analysis and a compressed time-series analysis), using OCC methods to recognize the species. Then, we tested the performance of a compressed time-series model for S. alterniflora detection and evaluated the expansibility of this approach when it was applied to a larger region. Our principal findings are as follows: (1) Maxent and BSVM performed equally well, and Maxent appeared to have a more balanced performance over the summer months; (2) the Maxent model with the Default Parameter Set (Maxent-DPS) showed a slightly higher accuracy and more overfitting than Maxent with the Akaike Information Criterion corrected for small samples sizes (AICc)-selected parameter set model, but a t-test found no significant difference between these two settings; (3) April and December were deemed to be important periods for the detection of S. alterniflora; (4) a compressed time-series analysis model—including only three variables (December NDVI, March green and the third Principal Component in January, PC3)—yielded higher accuracy than single-scene analyses, which indicated that time-series analysis can better detect S. alterniflora than single-scene analyses; and (5) the Maxent model using the reconstructed optimal variables and 70 training samples over a larger region produced encouraging results with an overall accuracy of 90.88% and a Kappa of 0.78. The one-class classification method combined with a phenology-based detection strategy is therefore promising for the application of the long-term detection of S. alterniflora over extended areas.

Delimitation of permanent preservation areas of Paurá Lagoon (Middle Coast of Rio Grande do Sul, Brazil) using multitemporal satellite image analysis

Permanent Preservation Areas (PPA) are determined by the Brazilian Forest Code (Federal Law nº 12.651/2012) to protect biodiversity, soil, water, and climatic integrity. Around lakes and lagoons in rural areas, the law establishes marginal strips of PPA with a minimum width of 100 m (or 50 m for lakes with less than 20 ha). Some of these water bodies may have their surface dimensions markedly changed due to seasonal variations. PPA demarcated during periods of maximum water level would present ecological advantages. However, such variations were not included as criteria for PPA around lakes and lagoons in the new 2012 Forest Code. Moreover, seasonal variations effects are not yet sufficiently known in water bodies of most regions. In this work, a methodology previously developed was used to delimitate and measure water surface area and PPA of Paurá Lagoon during maximum water overflow - due to rain water excess (WE), and water deficit - due to rain water scarcity (WS). This lagoon is situated in a coastal area ranked as conservation priority in Brazil (31°34’ S, 51°18’ W; 31°34’ S, 51°17’ W; 31°35’ S, 51°18’ W and 31°35’ S, 51°19’ W). Analyses of rainfall records covering the 1992-2012 time series, water balance and remote sensing with freely available GIS application (SPRING) were employed to select satellite images from WS and WE dates. Two Landsat-5 TM images, dated 29/04/2009 (WS) and 06/09/1998 (WE) were selected and geoprocessed to detect differences in areas under WS and WE, respectively. For lagoon surface area and PPA, 66.29 ha and 42.36 ha were calculated during WS, and 92.27 ha and 53.25 ha during WE, respectively. At maximum WE (local winter and spring), lagoon surface area was 25.98 ha larger, while PPA had an addition of 10.89 ha. Although Landsat images have spatial resolution limitations, the methodology allowed the identification of the most suitable annual period to delimitate a larger area around the water body. Following in situ demarcation, the resulting larger PPA may provide superior ecological benefits to priority conservation regions. The methodology tested may be a useful tool to integrated management of lakes and wetlands in coastal zones.

Morfodinâmica da desembocadura da Lagoa do Peixe, litoral sul do Brasil

A morfologia de canais é resultado do ambiente em que se encontram, assim como de todas variáveis físicas atuantes. Se a desembocadura está situada em zonas costeiras, a tendência à instabilidade é amplificada pelo próprio meio. Neste artigo são apresentados os resultados do estudo morfodinâmico do canal de comunicação entre a Lagoa do Peixe e o Oceano Atlântico, localizado no Parque Nacional da Lagoa do Peixe, litoral médio do Rio Grande do Sul, Brasil. Também é medida a variabilidade da linha de praia adjacente ao parque. Com o objetivo de determinar a classifica- ção do canal e sua dinâmica natural, foram utilizados uma série de 47 anos de imagens Landsat (1973 – 2009), dados de precipitação da Agencia Nacional de Águas e equações. A interpretação da série temporal e os cálculos das médias de precipitação permitiram descrever o canal da Lagoa do Peixe como um canal de maré, com mecanismo de assoreamento morfodinâmico influenciado pelo regime de precipitação pluviométrica. Os resultados das equações indicaram como fatores determinantes à sua oclusão o prisma de maré e transporte e deposição sedimentar em frente a desembocadura, associados à deriva litorânea de padrão bidirecional da área de estudo. Sua desembocadura possui caráter intermitente e é instável quanto ao seu posicionamento e geometria. A mobilidade da linha de praia adjacente ao Parque Nacional da Lagoa do Peixe foi verificada pelo método de pontos extremos, pixel a pixel, entre duas imagens Landsat de mesmo mês, uma de 1987 e outra de 2009, sendo constatada erosão ao sul da desembocadura do canal da Lagoa do Peixe e acreção ao norte da mesma.

Seasonal Dynamics and Community Composition of Epilithic Microalgae in Relation with Environmental Factors at Northwest coast of Jeddah, The Red Sea

Intertidal epilithic microalgae play very important role as feed of higher organisms. Taxonomical composition of epilithic algae and their seasonal dynamics in relation with environmental factors were studied at middle coast of Saudi Arabia, namely Yanbu, Ar-Rayis, Mastorah, Rabigh and Thuwal, the Red Sea. Temperature, salinity and pH varied from 22.10-32.02°C, 38.72-39.35 psu, and 8.40-8.63, respectively throughout the study. A total of 87 epilithic microalgal species belonging to 4 families was identified: 79 Bacillariophyceae, 5 Cyanophyceae, 2 Dinophyceae, and 1 Cryptophyceae. The epilithic microalgal abundance varied from 2.32 × 105 cells/L to 7.66 × 105 cells/L during the study with an average of 4.03 × 105 cells/L. The lowest and highest abundance of epilithic microalgae occurred in winter and summer at Mastorah and Rabigh, respectively. Among the microalgae taxa, diatoms were the dominant group which was 91.01%, followed by Cyanophyceae (5.62%), Dinophyceae (2.25%) and Raphidophyceae (1.12%). Among diatom, the centric and pennate diatoms were 74.07% and 25.93%, respectively throughout the study. The occurrence frequency analysis revealed that high frequently observed epilithic microalgae were Licmophora flabellata, L. paradoxa, L. remulus, Navicula vula, N. incerta and N. transitans throughout the study. Therefore, it could be said that diatoms are the major group of epilithic microalgae which show high abundant in summer at the northwest coast of Jeddah, Saudi Arabia, the Red Sea. Second dominant group was Cyanophyceae, and the dominant species was Spirulina subsalsa among epilithic microalgal community.

Saltmarshes Response to Human Activities on a Prograding Coast Revealed by a Dual-Scale Time-Series Strategy

On many prograding coasts, human activities such as alien species introduction and tidal flat reclamation, as countermeasures against land scarcity, are having a major impact on saltmarshes. Despite their capacity for regeneration given ample sediment supply, saltmarshes are likely to disappear if they continue to be impacted by such activities without effective monitoring and protection. However, effective monitoring requires a combination of saltmarsh species mapping and short timespan change analyses, which are difficult to accomplish due to the widespread, rapid, and complex characteristics of saltmarsh replacement in the region. Integrating multi-source remote sensing data with a times-series strategy, this study constructed saltmarsh species maps for the Jiangsu middle coast with 89.4 % overall accuracy (∼16.1 % higher than that achieved by the individual image classification method). Subsequently, we used these maps to explore the interaction between saltmarshes and human activities by a dual-scale analysis: macroscale analysis, aiming at saltmarsh ecosystem wide processes, to reflect the general evolutionary trend for all saltmarsh species, and microscale analysis, focusing on a species-specific process, to reveal the focal response mechanism for Spartina alterniflora. The results show that: (1) In the past 20 years, over 97.6 % (227.72 km2) of the loss of native saltmarshes (Phragmites australis and Suaeda salsa) was caused by tidal flat reclamation, and the invasion of S. alterniflora poses a potential threat to the future well-being of the native saltmarshes. The limited remaining area of the native saltmarshes, together with their long regeneration time, suggests that future land replacement will be dominated by the interaction between S. alterniflora and reclamation. (2) Intertidal reclamation promotes the expansion of S. alterniflora, as revealed by high linear correlations (mainly with R 2 > 0.6) between the lateral expansion rate of S. alterniflora and reclamation. The prerequisite for this correlation was a sufficient width of S. alterniflora (850–1000 m for most of the coasts), and we propose that by maintaining this critical width, S. alterniflora will be capable of relatively rapid invasion after reclamation.

SPATIAL-TEMPORAL DETECTION OF CHANGES ON THE SOUTHERN COAST OF THE BALTIC SEA BASED ON MULTITEMPORAL AERIAL PHOTOGRAPHS

Digital photogrammetry and remote sensing solutions applied under the project and combined with the geographical information system made it possible to utilize data originating from various sources and dating back to different periods. Research works made use of archival and up-to-date aerial images, satellite images, orthophotomaps. Multitemporal data served for mapping and monitoring intermediate conditions of the Baltic Sea shore zone without a need for a direct interference in the environment. The main objective of research was to determine the dynamics and volume of sea shore changes along the selected part of coast in the period of 1951-2004, and to assess the tendencies of shore development in that area. For each of the six annual data sets, the following were determined: front dune base line, water line and the beach width. The location of the dune base line, which reflects the course of the shoreline in a given year was reconstructed based on stereoscopic study of images from each annual set. Unidirectional changes in the period of 1951-2004 occurred only within 10% of the examined shore section length. The examined shore is marked by a high and considerable dynamics of changes. Almost half of the shore, in particular the middle coast shows big changes, in excess of 2 m/year. The limits of shoreline changes ranged from 120 to -90 m, and their velocity from 0 to 11 m/year, save that the middle and west parts of the examined coast section were subjected to definitely more intense shore transformations. Research based on the analysis of multitemporal aerial images made it possible to reconstruct the intermediate conditions of the Baltic Sea shoreline and determine the volume and rate of changes in the location of dune base line in the examined period of 53 years, and to find out tendencies of shore development and dynamics.