Tidal Flat Ecosystem Research Articles

Feeding ecology of Liza spp. in a tidal flat: Evidence of the importance of primary production (biofilm) and associated meiofauna

Grey mullets are unique among temperate-region fish species in their ability to feed on mudflat biofilm. In this study, we examined mullet feeding strategies on biofilm and associated meiofauna by using a diet study and stable isotope analysis to explore functional interactions between mullets and tidal flats. A stomach vacuity investigation showed that mullets did not import any materials from subtidal areas into the mudflat but exported mud, biofilm, and associated meiofauna. The results of mullet stomach content and fecal analyses, when compared to the availability of tidal flat resources, showed evidence of mullets' ability to ingest and assimilate biofilm and to concentrate major meiofauna grazers such as nematodes, copepods and, secondarily, foraminifers and ostracods. Isotopic ratios confirmed diet investigations, and as recently shown in salt marsh habitats, mullets exhibited an intermediate trophic position, supporting the hypothesis that they can assimilate both biofilm and major meiofauna grazers. The function of the tidal flat as a feeding habitat for gray mullets and the role of mullets as the main export pathway of biofilm from tidal flat ecosystems are discussed.

Influence of Spartina Colonization on the Supply and Accumulation of Organic Carbon in Tidal Salt Marshes of Northern Jiangsu Province, China

Abstract GAO, J.; BAI, F.; YANG, Y.; GAO S.; LIU, Z., and LI, J., 2012. Influence of Spartina colonization on the supply and accumulation of organic carbon in tidal salt marshes of northern Jiangsu Province, China. Two species of cordgrass (Spartina anglica Hubbard and Spartina alterniflora Loisel.) were artificially introduced to the intertidal zone of Jiangsu Province, China, in 1963 and 1982, respectively. However, as alien species, the impact of Spartina on the tidal flat ecosystem remains largely unknown. Suaeda salsa and Phragmites australis, two native plants in the intertidal zone of northern Jiangsu Province, China, are C3-type plants, whereas the Spartina species are C4-type plants. In this article, we investigate the vertical distribution of total organic carbon, total nitrogen, and organic carbon isotope ratios in different ecosystems associated with the northern Jiangsu tidal flats; analyze changes in the organic carbon sources in the tidal flat sediments after Spartina colonization; compare ...

Spatial and temporal CO<sub>2</sub> exchanges measured by Eddy Covariance over a temperate intertidal flat and their relationships to net ecosystem production

Abstract. Measurements of carbon dioxide fluxes were performed over a temperate intertidal mudflat in southwestern France using the micrometeorological Eddy Covariance (EC) technique. EC measurements were carried out in two contrasting sites of the Arcachon flat during four periods and in three different seasons (autumn 2007, summer 2008, autumn 2008 and spring 2009). In addition, satellite images of the tidal flat at low tide were used to link the net ecosystem CO2 exchange (NEE) with the occupation of the mudflat by primary producers, particularly by Zostera noltii meadows. CO2 fluxes during the four deployments showed important spatial and temporal variations, with the flat rapidly shifting from sink to source with the tide. Absolute CO2 fluxes showed generally small negative (influx) and positive (efflux) values, with larger values up to −13 μmol m−2 s−1 for influxes and 19 μmol m−2 s−1 for effluxes. Low tide during the day was mostly associated with a net uptake of atmospheric CO2. In contrast, during immersion and during low tide at night, CO2 fluxes where positive, negative or close to zero, depending on the season and the site. During the autumn of 2007, at the innermost station with a patchy Zostera noltii bed (cover of 22 ± 14% in the wind direction of measurements), CO2 influx was −1.7 ± 1.7 μmol m−2 s−1 at low tide during the day, and the efflux was 2.7 ± 3.7 μmol m−2 s−1 at low tide during the night. A gross primary production (GPP) of 4.4 ± 4.1 μmol m−2 s−1 during emersion could be attributed to microphytobenthic communities. During the summer and autumn of 2008, at the central station with a dense eelgrass bed (92 ± 10%), CO2 uptakes at low tide during the day were −1.5 ± 1.2 and −0.9 ± 1.7 μmol m−2 s−1, respectively. Night time effluxes of CO2 were 1.0 ± 0.9 and 0.2 ± 1.1 μmol m−2 s−1 in summer and autumn, respectively, resulting in a GPP during emersion of 2.5 ± 1.5 and 1.1 ± 2.0 μmol m−2 s−1, respectively, attributed primarily to the seagrass community. At the same station in April 2009, before Zostera noltii started to grow, the CO2 uptake at low tide during the day was the highest (−2.7 ± 2.0 μmol m−2 s−1). Influxes of CO2 were also observed during immersion at the central station in spring and early autumn and were apparently related to phytoplankton blooms occurring at the mouth of the flat, followed by the advection of CO2-depleted water with the flooding tide. Although winter data as well as water carbon measurements would be necessary to determine a precise CO2 budget for the flat, our results suggest that tidal flat ecosystems are a modest contributor to the CO2 budget of the coastal ocean.

Influence of flushing on the estuarine tidal flat ecosystem developed in the mouth of Ohtagawa flood way

Influence of flushing on the estuarine tidal flat ecosystem developed in the mouth of Ohtagawa flood way

Submarine groundwater discharge (SGD) as a main nutrient source for benthic and water-column primary production in a large intertidal environment of the Yellow Sea

The biogeochemistry and magnitude of submarine groundwater discharge (SGD) was investigated in one of the largest tidal flat ecosystems worldwide, along the Yellow Sea coast. A representative semi-enclosed embayment located in the south eastern Yellow Sea, Hampyeong Bay, was chosen for this purpose. Groundwater and seawater samples were collected in three seasons (May, July, and September) and analyzed for Ra isotopes, nutrients, and photosynthetic pigments. The biogeochemistry of SGD was strongly influenced by tidal oscillations and seasonal precipitation changes and switched from a brackish, nutrient-enriched regime in May and July to an exclusively saline regime, with lower nutrient concentrations, in September. SGD magnitudes, calculated by using a 226Ra mass balance model, were 0.14 m 3 m − 2 d − 1 in May and 0.35 m 3 m − 2 d − 1 in September. A nutrient mass balance was established for the two campaigns, which suggests that SGD causes the flushing of substantial amounts of pore water nutrients into this embayment; because of SGD, the embayment acts as a source of dissolved inorganic silicates (DSi) that are transported to the open ocean. Potential C fixation rates derived from this nutrient mass balance were compared with two different models for water-column phytoplankton productivity based on water-column Chl a and local irradiation levels. The Chl a-based models generally showed lower C fixation rates than the nutrient-based mass balance, indicating removal of up to 70% of the nutrients by other primary producers, such as benthic algae. During monsoon season, when benthic algal biomass is high and nutrient fluxes are substantial due to a terrestrial component, SGD — driven benthic primary production could play a significant role in this large tidal flat ecosystem.

한국 갯벌 생태 등급도의 개발 필요성과 방향

There is a host of habitat assessment systems available to evaluate and grade tidal flat ecosystems in Korea. Nevertheless, we recognize the need to develop a better ecological scheme to improve reliability and accuracy given the importance of using an empirical approach in assigning grades to indicators and the limitation of current systems which evaluate tidal flats on a regional basis. A preferable system would be one that enables habitat mapping within a tidal flat, provides a diagnosis of ecological stress/health, has a high level of ecological relevance, communicability, and statistical robustness, and enables evaluation of diverse habitats within a tidal flat. The following points should be considered in framing such a system. Indicators should discriminate habitat quality into five to seven grades accomodating diverse characteristics and conservation value of a habitat, and the grading should be made from frequency distribution of indicators based on nationwide data.We suggest the following tasks in crafting such a system: ⅰ) The decision on selection of indicators should be made based on accuracy of assessment and practical application; ⅱ) effects of physical habitat conditions on variability of indicators should be reflected; and, ⅲ) further works on stress/health indicators should be addressed for adopting a multiple-indicator approach which reduces misdiagnosis.

Comparison of Organic Matter Dynamics among Tidal Flat Ecosystems of Different Biota with Tidal Flat Experimental Equipment

Comparison of Organic Matter Dynamics among Tidal Flat Ecosystems of Different Biota with Tidal Flat Experimental Equipment

Differences in microphytobenthos and macrofaunal abundances associated with groundwater discharge in the intertidal zone

We investigated the impact of intertidal groundwater seepage on benthic microalgae and macrofauna in 4 study sites located in 2 large tidal flat ecosystems along the western coast of Korea by comparing the chemical, physical, and biological characteristics of 'glossy' seepage sites with those of nearby areas without visually distinct groundwater discharge (dry sediment surface). At 3 of the 4 sites, sediment properties as well as pore water chemistry were similar in groundwater seepage and dry areas. At the 4th study site, the groundwater seepage areas were more coarse- grained compared to the dry areas. Here, the groundwater seepage also had lower salinity and higher nutrient concentrations than the pore water of the dry area and the seawater in a nearby tide pool. Although diatoms were the dominant algal class in seepage and dry areas alike, the seepage areas in 3 of the sites had elevated contributions of other marker pigments such as chlorophyll (chl) b compared to the dry areas. Chl a concentrations were higher in all seepage areas compared to dry areas, and all dry areas had high pheophytin a:chla ratios, indicating a substantial amount of degraded algal material. In the seepage areas of 3 of the sites, we found large numbers of the snail Batillaria cumingi, while crab burrows of Scopimera sp. were only present in the neighboring dry areas. Correlations of sediment chl a concentrations with physicochemical properties of the ambient pore water indicated that microphytobenthos responded specifically to groundwater seepage, which may provide shelter from desiccation and salt stress during emersion of the tidal flat. Our results sug- gest that globally common groundwater seepage significantly impacts the ecosystem structures and microphytobenthos production of the tidal flats.

Assessment of some marine ecosystems using sustainable utilization indicators in Hai Phong—Quang Ninh coastal area, Vietnam

This study is aimed at analyzing key indicators for the evaluation of changes and tendencies of sustainable utilization and management in some marine ecosystems in the coastal waters of Hai Phong - Quang Ninh area. To complete this study, the methods employed consisted of the application of remote sensing data and geographic information systems to extract information on spatial distribution of mangrove and tidal flat ecosystems, as well as on the reclamation area for human development and indicator investigation and analysis, using remote sensing extracted and field survey monitored data with Microsoft Excel (MS Excel). Applying indicators for sustainable utilization and management of marine ecosystems, developed in recent studies for the Hai Phong - Quang Ninh area, demonstrated changes and trends in significant ecosystems, such as coral reefs and mangroves. The outcomes showed that from 1998 to 2003, living coral cover was reduced by 20% on average in the Ha Long Bay area and by 13% in Cat Ba (Hang Trai - Dau Be), and projected that living coral cover would be reduced by a further 10% to 50% by 2010. The number of coral species was much reduced by 15% to 72% in the Ha Long—Cat Ba area. Mangrove area also decreased between 1995 and 2004, particularly after 2000, and is projected to be only 10,000 ha in 2010 in Quang Ninh. Marine ecosystems in the coastal waters of Hai Phong - Quang Ninh area have degraded significantly, particularly coral reefs, mangroves and tidal flats.

Oxygen Production and Consumption Mechanisms in the Tidal Flat Ecosystem - Analysis of Ecological Connectivity Hypoxia Model (ECOHYM) -

ECOHYM (the Ecological Connectivity Hypoxia Model) revealed the daily and annual dynamics of the vertical biochemical-physical oxygen production and consumption rate in the tidal flat quantitatively, based on the validation from two perspectives: (1) the whole estuary, composed of temporal-spatial mutual linkage of the central bay-tidal and benthic-pelagic ecosystems (holistic approach) and (2) each biochemical and physical processes (elemental approach). The benthic oxygen consumption caused by biochemical production during daytime was higher than nighttime due to oxygen production of photosynthesis of benthic algae. This photosynthesis makes the benthic system sometimes an oxygen source for the pelagic system during daytime, although the benthic system is always an oxygen sink during night time.

Cultivable bacteria from bulk water, aggregates, and surface sediments of a tidal flat ecosystem

Most-probable-number (MPN) dilution series were used to enumerate and isolate bacteria from bulk water, suspended aggregates, the oxic layer, and the oxic–anoxic transition zone of the sediment of a tidal flat ecosystem in the southern North Sea. The heterotrophic aerobic bacteria were able to grow on agar-agar, alginate, cellulose, chitin, dried and ground Fucus vesiculosus, Marine Broth 2216, palmitate, and starch. MPN counts of bulk water and aggregate samples ranged between 0.18 × 101 and 1.1 × 106 cells per milliliter and those of the sediment surface and the transition zone between 0.8 × 101 and 5.1 × 107 cells per gram dry weight. Marine Broth and F. vesiculosus yielded the highest values of all substrates tested and corresponded to 2.3–32% of 4,6-diamidinophenyl indole cell counts. Strains of seven phylogenetic classes were obtained: Actinobacteria, Bacilli, α- and γ-Proteobacteria, Sphingobacteria, Flavobacteria, and Planctomycetacia. Only with agar-agar as substrate could organisms of all seven classes be isolated.

Short-term dynamics of bacterial communities in a tidally affected coastal ecosystem

Tidal effects on the composition of free-living (FL) and particle-associated (PA) bacterial communities were studied in a tidal flat ecosystem in the southern North Sea. Denaturing gradient gel electrophoresis targeting the 16S rRNA gene and the 16S rRNA of Bacteria, Bacteroidetes, Alphaproteobacteria and the Roseobacter clade was applied. Despite strong tidal variations in the quantity and, depending on the season, also the quality of suspended matter as well as variations in bacterial activity, the bacterial community composition remained rather stable. FISH showed some variations of the community composition, but these were not related to typical tidal situations. Variations were higher during tidal cycles in May and July compared with November. Bacteroidetes, Alpha- and Gammaproteobacteria constituted the majority of the bacterial communities but relative proportions of the different groups varied considerably. On particles, Betaproteobacteria were also detected to substantial proportions. The Roseobacter clade constituted up to 90% of FL but only 30% of PA Alphaproteobacteria. Banding patterns of the Bacteroidetes-specific amplicons, and in particular those targeting the 16S rRNA, revealed tidally induced effects, as several bands appeared or disappeared at distinct events such as slack water or resuspension. Sequencing of prominent bands revealed predominantly phylotypes reported previously from this ecosystem.

A benthic–pelagic coupled ecosystem model to estimate the hypoxic estuary including tidal flat—Model description and validation of seasonal/daily dynamics

A new ecosystem model – the Ecological Connectivity Hypoxia Model (ECOHYM) – was developed and applied to Tokyo Bay, a hypoxic estuary in Japan. ECOHYM permits study of the dynamics and mechanisms of hypoxia from two perspectives: (1) the whole estuary, composed of temporal-spatial mutual linkage of benthic–pelagic or central bay-tidal flat ecosystems (holistic approach), and (2) each biochemical and physical process, contributing to oxygen production/consumption (elemental approach). ECOHYM evaluates the oxygen–carbon–nitrogen–phosphorus-coupled cycle driven by physical and biochemical processes. The processes mechanically describe the ecosystem network consisting of benthic–pelagic and central bay–tidal flat ecosystem coupling. The model also describes the early diagenetic processes of the benthic ecosystems by setting a micro-scale vertical spatial resolution due to the drastic vertical change of benthic biological metabolism and its high contribution to total oxygen consumption. Model variables were mainly selected based on low trophic level; namely, phytoplankton, zooplankton, detritus, dissolved organic matter, NH 4–N, NO 3–N, PO 4–P, benthic algae, suspension feeders, deposit feeders (benthic faunas), dissolved oxygen (DO) and oxygen demand units (ODU, representing the stoichiometric expression of Mn 2+, Fe 2+ and S 2− oxygen demand). Detritus was divided into fast-labile, slow-labile and refractory parts. Bacterial mineralization processes were divided into oxic, suboxic and anoxic fractions. The model was applied for a time frame of 100 years under seasonal forcing functions to achieve an annual periodical steady state. The model results revealed that the seasonal dynamics were more noticeable than the daily/tidal dynamics in the central bay area. In contrast, the daily/tidal dynamics were determinant in the tidal flat area. Calculated seasonal dynamics in the central bay and daily/tidal dynamics in the tidal flat were in good agreement with the observed data. In particular, the model succeeded in reproducing the following vertical DO profiles during the hypoxic season (summer): (1) high oxygen at the sea-surface and hypoxia at the sea-bottom in the central bay area, (2) the reduced thickness of the benthic oxic layer in the central bay area, and (3) the drastic change of DO micro-profiles between daytime and nighttime of the benthic system in the tidal flat areas. Oxygen fluxes at the sediment–water interface in the model also reproduced the in situ observed values both in the central bay and tidal flat areas.

Role of Waterfront Geoenvironments in the Relationships between Birds, Sediments and Benthos

This paper describes the role of suction and related geophysical environmental conditions in the relationships between birds, sediments and benthos. We performed integrated sets of field observations/surveys and analyses at Roberts Bank and Sidney Bay in Canada and the Banzu flat in Japan. The results indicate that for a wide range of sediment types from fine sands to clay, suction is a performance index controlling the benthos diversity foraged by shorebirds. The suction dynamics was found to be closely linked to the feeding activity of Dunlins. We made clear the working mechanism in view of Ecological Geotechnics. The present finding highlights the importance of waterfront geoenvironments in the tidal flat ecosystems, and will effectively contribute to the conservation and restoration of habitats with diverse ecological activity.

Effects of phytoplankton bloom in a coastal ecosystem on the composition of bacterial communities

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 48:47-60 (2007) - doi:10.3354/ame048047 Effects of phytoplankton bloom in a coastal ecosystem on the composition of bacterial communities Beate Rink1, Susanne Seeberger1, Torben Martens1, Claus-Dieter Duerselen2, Meinhard Simon1, Thorsten Brinkhoff1,* 1Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, PO Box 2503, 26111 Oldenburg, Germany 2AquaEcology, Marie-Curie-Straße 1, 26129 Oldenburg, Germany *Corresponding author. Email: thorsten.brinkhoff@icbm.de ABSTRACT: We studied the composition of free-living and particle-associated bacterial communities during the course of the phytoplankton succession in spring and early summer in the Wadden Sea, a tidal flat ecosystem in the southern North Sea. We applied the denaturing gradient gel electrophoresis (DGGE) approach based on PCR-amplified 16S rRNA gene fragments and, in addition to Bacteria-specific primers, used primer sets targeting Alphaproteobacteria, the Roseobacter-clade and the Bacteroidetes phylum. Even though the application of the primer sets targeting Bacteria and Alphaproteobacteria detected some changes, they were most pronounced with those targeting the Roseobacter-clade and Bacteroidetes. The changes were supported by a correspondence analysis, which showed a statistically significant correlation of the DGGE banding patterns of the Roseobacter-specific PCR with the composition of the phytoplankton (p = 0.03). This indicates that changes in the phytoplankton composition in this habitat are not reflected by changes in the most abundant or most readily amplifiable phylotypes. The findings rather suggest that few, specialized, heterotrophic bacteria are most responsive to the organic matter supplied by distinct phytoplankton communities and that the main part of organic matter in the Wadden Sea is utilized by generalists. Sequence analyses of excised bands revealed a high diversity for the Bacteria- and Bacteroidetes-targeted approaches. The bacterial community detected by the primer set targeting Alphaproteobacteria, however, was mainly composed of bacteria affiliated to the Roseobacter-clade. KEY WORDS: Free-living bacteria · Particle-attached bacteria · Bacteroidetes · Roseobacter · Phytoplankton · Denaturing gradient gel electrophoresis · Wadden Sea Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 48, No. 1. Online publication date: June 20, 2007 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2007 Inter-Research.

Enzymatic evaluation of decomposition in mosaic landscapes of a tidal flat ecosystem

Organic matter decomposition is an important ecological function in tidal flat ecosystems, and extracellular hydrolytic enzyme activities can be used as indices of this process. In this study, the spatial and temporal variations of enzyme activities were determined to establish easily measured variables that could be used to assess wetland functions. Seven sampling sites belonging to the hydrogeomorphic subclasses estuary, foreshore, and lagoon were selected in the intertidal zone of the Obitsu River Delta and the Banzu Tidal Flat in Tokyo Bay, Japan. Ten field surveys were conducted between June 2001 and April 2003. In each survey triplicate sediment samples were collected from each sampling site. For each sample, fluoresceindiacetate hydrolysis (FDH), β-glucosidase (GLU), and β-acetylglucosaminidase (AGA) activities were measured. Among the 210 samples, the means and standard deviations were 0.018 ± 0.011 unit g−1 h−1 for FDH, 0.074 ± 0.043 mmol kg−1 h−1 for GLU, and 0.043 ± 0.041 mmol kg−1 h−1 for AGA. According to analysis of variance, sampling time, site location, and their interaction significantly influenced FDH activity. Both the sampling time and sampling location affected GLU and AGA activities, although no significant interaction was found. GLU and AGA activities were higher in the estuary sites than in the foreshore sites and the lagoon site. GLU and AGA activities differed among the estuary sites, although there were no significant differences in GLU and AGA activities among the foreshore beach sites. We recorded significant temporal changes of GLU and AGA activities, and seasonal changes differed across the three years of the study.

Diversity and abundance of Gram positive bacteria in a tidal flat ecosystem

Gram positive bacteria recently have been identified as important components of freshwater ecosystems and are also present in marine environments. However, their quantitative significance and possible role in the latter systems is still little studied, in particular in coastal regions. Therefore, we investigated the abundance and composition of Gram positive bacteria in the Wadden Sea, a tidal flat ecosystem in the German Bight of the North Sea. Applying fluorescence in situ hybridization we found that Actinobacteria constitute 4-7% of total bacteria in the Wadden Sea and slightly higher proportions in a freshwater drainage channel connected to the sea by a sluice. The application of denaturing gradient gel electrophoresis of 16S rRNA gene fragments after amplification by an Actinobacteria-specific primer set and subsequent sequencing showed that the composition of the actinobacterial community in the Wadden Sea was distinctly different from that in the freshwater system. A bacterial clone library of 111 clones yielded eight Gram positive phylotypes which are related closely to other marine phylotypes including the Marine Actinobacteria Clade but also to freshwater phylotypes. We applied dilution cultures, enriched with various biopolymers, Marine Broth and Fucus vesiculosus extracts, for isolating bacteria from the bulk water, suspended aggregates, the oxic surface and oxic/anoxic transition zone of the sediment. Fifty-three isolates affiliated to seven families of the order Actinomycetales and nine isolates to the family Bacillaceae. The salinity range (1-45 per thousand NaCl) and growth optimum of 14 strains from various families showed that all except one strain exhibited a rather broad range of sustained growth from 1 per thousand to >or= 20 per thousand NaCl and several strains exhibited an optimum of > 10 per thousand NaCl. The results indicate that the Gram positive bacterial community in the Wadden Sea is surprisingly diverse and consists mainly of indigenous species which appear to be well adapted to the environmental conditions of this coastal ecosystem.

大河川河口干潟における平衡底質粒度分布の評価方法

It is very important for an environmental assessment of tidal flat ecosystem such as some benthic animals that clarifying formation mechanism of particle size distribution of sediment. The main aim of this research is the development of a method to evaluate the equilibrium particle size distribution in large river mouth. We considered a river with larger influences of waves than river currents and modeled the formation mechanism of sediment. It was assumed that the sand particles which correspond to the critical shear stress under waves deposit and form a particle size distribution depending on the frequency of disturbance of waves in this model. The particle size distributions which estimated based on a wave statistical data well coincided with field survey data.

Three Years Changes in the Sediment Quality and Benthic Fauna in the Artificial Tidal Flat and Sea Grass Bed Constructed in AGO Bay with Use of Muddy Dredged Sediment.

The technology for constructing artificial tidal flat which is enhancing the biological productivity in relatively oligotrophic tidal flat ecosystem by controlling the sediment nutrient for the benthos by using dredged sediment has been developed in AGO bay. The two types of experimental tidal flat were constructed (Experimental tidal flat 1: 3000m2, Experimental tidal flat 2: 4200m2). And Zostera marina bed was planted in front of the experimental tidal flat 1, 2. Then these sediment qualities and benthos habitat were monitored every season for three years. After construction, It is clear that the abundance andspecies number of benthos in the artificial tidal flat were increased more than 3-4 times before construction. And more in Zostera bed, they were also increasedmore than 10 times without Zostera bed.

Study on the Evaluation Method using the Habitat Suitability Index (HSI) for the Tidal Flat Restoration

A lot of environmental restoration projects at the coastal zone have been implemented, though the evaluate method is still under the developing stage. Therefore it is important to understand theecosystem and establish the evaluation technique for the tidal flat ecosystem. This study applied and examined the Habitat Suitability Index (HSI) model to evaluate benthos habitat suitability on the tidal flat. As a result, to use amethod of “Minimum Function” which selects the minimum Suitability Index (SI) could improve the accuracy of the HSImodel. This does not means improvement of the data obtained, but specification and selection of the dominant factor affecting on the benthos habitats.