Brackish Lagoon Research Articles

The Lower Jurassic Johansen Formation, northern North Sea – Depositional model and reservoir characterization for CO2 storage

The Lower Jurassic, Johansen Formation sandstone, located in the Northern North Sea, has been proposed as a reservoir candidate for CO2 storage by Norwegian authorities. The objective of this study is to evaluate the reservoir quality of the Johansen Formation, as function of depositional history and architecture.We propose a depositional model comprising an early phase delta progradation, with clinothems building into deep waters, associated with delta front and pro-delta turbidites sourced from river mouths or/and upper delta front collapse. During a subsequent, aggradational stage, thick spit bar deposits developed in the southern, down-current part, sheltering a brackish lagoon, before rapid transgression caused back-stepping and preservation of sandy deposits encased in mud. Considering the depositional model presented, the inferred high porosity spit bar deposits would provide a suitable injection site and reservoir for CO2.Climatic controlling factors, rather than structural, are interpreted to have exerted the major force on the asymmetric sand distributions observed in the Johansen Formation, an architectural style which is repeated in later Jurassic successions on the Horda Platform. On a local scale, accommodation was created by differential compaction above rotated, Permian fault blocks, in addition to regional, post-thermal subsidence and rising sea-level.

Salinity is the major factor influencing the sediment bacterial communities in a Mediterranean lagoonal complex (Amvrakikos Gulf, Ionian Sea)

Lagoons are naturally enriched habitats, with unstable environmental conditions caused by their confinement, shallow depth and state of saprobity. The frequent fluctuations of the abiotic variables cause severe changes in the abundance and distribution of biota. This relationship has been studied extensively for the macrofaunal communities, but not sufficiently so for the bacterial ones.The aim of the present study was to explore the biodiversity patterns of bacterial assemblages and to examine whether these patterns are associated with biogeographic and environmental factors.For this purpose, sediment samples were collected from five lagoons located in the Amvrakikos Gulf (Ionian Sea, Western Greece). DNA was extracted from the sediment and was further processed through 16S rRNA pyrosequencing.The results of this exploratory study imply that salinity is the environmental factor best correlated with the bacterial community pattern, which has also been suggested in similar studies but for macrofaunal community patterns. In addition, the bacterial community of the brackish lagoons is differentiated from that of the brackish-marine lagoons. The findings of this study indicate that the studied lagoons have distinct bacterial communities.

PLANKTONIC PRIMARY PRODUCTION AND COMMUNITY RESPIRATION IN SEVERAL COASTAL LAGOONS OF THE OUTER DELTA OF THE RIO MAGDALENA, COLOMBIA

To understand the responses of the plankton community to the negative large-scale human impacts in a tropical coastal lagoon complex, we carried out a regional survey on primary productivity (PP), community respiration (CR), and contribution of different size fractions of the phytoplankton to overall PP. This comparative study was undertaken in several coastal lagoons within the Outer Delta of the Río Magdalena (Colombia) during the dry season(February/March). PP was measured using the 14C-method with in situ-incubations and CR was determined as oxygen demand, using the Winkler technique. According to their salinities the lagoons were separated into a brackish water group (salinity range 5.9 – 21.8) and a freshwater group, the latter being influenced directly by the Río Magdalena. In all of the lagoons the productive layer did not surpass 1 m in depth due to selfshading by the high density of plankton (brackish lagoons) or due to high amounts of suspended inorganic sediment particles introduced into the freshwater lagoons from the Río Magdalena. The brackish lagoons contained high chl a concentrations (62 – 130 μg/l) and were extremely productive (0.72 – 1.25 mg C/l/h in the most productive depth, usually at 0.1 m). The concentrations of chl a in the freshwater lagoons were much lower (5.5 – 19 μg/l), also the PP (0.073 – 0.32 mg C/l/h). In all of the studied lagoons the photosynthetic active algae were very small, algae >20 μm (microalgae) played only a very insignificant role with respect to PP. The assimilation index (AI) was quite high (11.6 – 18.5 mg C/mg chl a /h). Only in two of the lagoons the relatively low AI (6.9 – 7.4 mg C/mg chl a /h) was probably due to senescent phytoplankton algae. The depth-integrated PP rates in the brackish lagoons ranged from 1.40 – 5.76 g C/m2/d. Especially the enormous rate of 5.76 g C/m2/d which was representative for the central part of Ciénaga Grande de Santa Marta demonstrated that this aquatic system belongs to the most productive ones world-wide. In the freshwater lagoons the daily PP measured 0.24 – 0.80 g C/m2. In the brackish lagoons the highly significant correlation between chl a and CR showed that the phytoplankton dark respiration was the dominant component, whereas the absence of a significant correlation in the freshwater lagoons demonstrated that here the heterotrophic microorganisms contributed more to community respiration. Only in three of the seven studied lagoons (among these Ciénaga Grande) planktonic primary production surpassed pelagic respiration, in the remaining four lagoons the deficit of organic material is probably compensated from allochthonous sources such as the mangrove fringes and/or river input

PHYTOPLANKTON COMPOSITION IN COASTAL LAGOONS OF DIFFERENT TROPHIC STATUS IN NORTHERN COLOMBIA DETERMINED BY MICROSCOPE AND HPLC-PIGMENT ANALYSIS

The regional differences in the composition of the phytoplankton assemblages in several coastal lagoons of the “Outer Delta of the Río Magdalena” (Caribbean coast of Colombia) were determined using microscopic counting and HPLC-pigment measurements. The study sites can be classified as 1) a group of limnic lagoons with relatively low (5.5-19 μg/l) chlorophyll a (chl a) concentrations and high inorganic suspension loading, 2) a group of brackish lagoons with high (62-90 μg/l) chl a concentrations and high amounts of organic seston, (two further lagoons form a transition between group 1 and 2, and 3) a fully marine Caribbean bay with very low (0.3 μg/l) chl a and seston concentrations. The regional variations in salinity of the lagoons are due to inflow of water from the Río Magdalena or to inflow of Caribbean Sea water. All lagoons are very shallow (less than 2 m) with small Secchi depths (20 to 30 cm). With the exception of the eutrophic brackish lagoons, where both methods indicated cyanobacteria to be the prevalent algal group, great discrepancies were encountered in all other study sites between the compositions of the algal communities obtained with both approaches. According to the microscopic analysis the phytoplankton of the marine Caribbean bay and the limnic and transient coastal lagoons consisted mainly (in several cases exclusively) of diatoms. The pigment analysis, on the other hand, indicated that cyanobacteria were the dominant algal group in all coastal lagoons, their percentage increased from the limnic over the transient to the brackish lagoons. Fractionated filtration of 14C-labelled phytoplankton revealed that algae of <5μm size in the coastal lagoons contributed 32-88% of the total radioactivity and that algae of >20μm size played only an insignificant role in primary production. Only in the Caribbean bay 14% of the 14CO2 was taken up by organisms >20μm. We assume that the small forms are greatly underrepresented in microscopic observations due to extreme difficulties in identification and counting caused by detritus and/or sediment loadings of the samples. We therefore believe that these small forms (probably mostly picoplanktonic cyanobacteria) are better represented by pigment analysis.

A Case Study on Aquatic Biodiversity and its Conservation from Chilika Lagoon, Orissa, East Coast of India

A Case Study on Aquatic Biodiversity and its Conservation from Chilika Lagoon, Orissa, East Coast of India Chilika the largest brackish water lagoon of India, a designated Ramsar site, is a wetland of international repute. It is one of the hotspot of biodiversity in the country and some rare, vulnerable and endangered species which have been listed in the IUCN Red list of threatened animals, inhabit in the lagoon.170 species of plankton, 61 species of foraminifera, 136 species of mollusca, 7 species of sponges, 31 species of polychaetes, 61 species of crustaceans, 4 species of sipuncula and 2 species of echinodermata are found in the lagoon. A total of 259 species of fishes, 28 species of prawns/shrimps and 35 species of crabs are recorded from the lagoon. The lagoon serves as a paradise for millions of aquatic birds during winter season. More than 175 species of birds are available in the lagoon. There are about 18 species of mammals and one river dolphin (Irrawady Dolphin) is found in the lagoon. There are 7 species of amphibians and 30 species of reptiles found in the lagoon.

Species composition of macrozoobenthos in lagoons of Sakhalin Island

Species composition of macrozoobenthos in lagoons of Sakhalin Island (in total, 637 species) is described on the base of cited data and results of author’s surveys. Its species composition is formed under influence of wide spectrum of environmental factors, as size of lagoon, water salinity, periodicity of connection with the sea and type of the water exchange, river discharge regime, climatic and geographical isolation, etc. Generally, 6 types of lagoons are determined on the coast of Sakhalin differed by composition of benthic fauna: 1) large semiclosed salty lagoon (Lake Busse in southern Sakhalin); 2) small semiclosed salty lagoons with water stratification and periodic connection with the sea (Lake Izmenchivoe and Lake Ptichye in southern Sakhalin); 3) large shallow semiclosed lagoons (in northern Sakhalin); 4) small isolated brackish lagoon (Kuegda Bay in northern Sakhalin); 5) closed oligosaline lagoons (Lake Tunaicha and Lake Aynskoe in southern Sakhalin); 5) isolated freshwater lagoons (Vavaysko-Chibisanskaya lake system in southern Sakhalin). Salty and freshwater lagoons are distinguished by the highest species diversity.

The Importance of Non-Native Prey, the Zebra Mussel Dreissena polymorpha, for the Declining Greater Scaup Aythya marila: A Case Study at a Key European Staging and Wintering Site.

The European population of Greater Scaup Aythya marila has experienced an alarming, ~60% decline in numbers over the last two decades. The brackish lagoons of the Odra River Estuary (ORE) in the south-western Baltic Sea, represent an important area for the species during the non-breeding season in Europe. The lagoons regularly support over 20 000 Scaup, with peaks exceeding 100 000 (38%–70% of the population wintering in NW Europe and the highest number recorded in April 2011–105 700). In the ORE, Scaup feed almost exclusively on the non-native Zebra Mussel Dreissena polymorpha. This mussel was present in the ORE already in the 19th century and continues to be superabundant. Using the results of 22 Scaup censuses (November to April 2002/2003 to 2013/2014) from the whole ORE (523 km2 of water), we show that Scaup flocks follow areas with the greatest area of occurrence and biomass of the Zebra Mussel, while areas with low mussel densities are ignored. The numbers of Scaup in the ORE are primarily related to the area of Zebra Mussel occurrence on the lagoon’s bottom (km2) in a non-linear fashion. Zebra Mussels were absolutely prevalent (97% of biomass) in the digestive tracts of birds unintentionally by-caught in fishing nets (n = 32). We estimate that Scaup alone consume an average of 5 400 tons of Zebra Mussels annually, which represents 5.6% of the total resources of the mussel in the ORE. Our results provide a clear picture of the strong dependence of the declining, migratory duck species on the non-native mussel, its primary food in the ORE. Our findings are particularly important as they can form the basis for the conservation action plan aimed at saving the north-western European populations of Scaup.

Structure of the parasite infracommunity of Sciades proops from the Japaratuba River Estuary, Sergipe, Brazil.

The catfish species Sciades proops inhabits muddy estuaries and shallow brackish lagoons, as well as freshwater. For these reasons, it is believed that this species may act as an intermediate, definitive and paratenic host in the life cycle of many parasites. From November 2010 to November 2011 and from August 2012 to July 2013, a total of 126 specimens of Sciades proops from the estuarine region of the Japaratuba River in the state of Sergipe, Brazil, were examined for parasites, of which 84.13% were infected by at least one species: Ergasilus sp. (Copepoda) (Prevalence P = 77.78%, Mean of Intensity MI = 10.08 ± 15.48, Mean Abundance MA = 14.27 ± 7.48) in the gills, Contracaecum sp. (P = 23.02%, MI = 20.59 ± 80.58, MA =39.12 ± 4.47) in the general cavity, Procamallanus sp. (P = 0.79%, MI = 1, MA = 0.01 ± 0.09), Raphidascaroides sp. (P = 2.31%, MI = 1.33 ± 0.58, MA = 0.33 ± 0.22) and Cuccullanus sp. (Nematoda) (P = 0.79%, MI = 1, MA = 0.01 ± 0.09) in the intestine, Ancyrocephalinae (Monogenea) (P = 0.79%, MI = 1, MA = 0.01 ± 0.09) in the gills, Pseudoacanthostomumpanamense (P = 1.59%, MI = 9.00 ± 8.49, MA = 0.14 ± 1.36) in the intestine, Clinostomum sp. (P = 1.59%, MI = 17.50 ± 23.33, MA = 0.29 ± 3.03) on the body surface and two unidentified metacercariae, referred to as Metacercaria 1 (P = 0.79%; IM = 1, MA = 0.01 ± 0.09) and Metacercaria 2 (Digenea) (P = 0.79%, MI = 7, MA = 0.06 ± 0.62) in the swim bladder. Ergasilus sp. was the dominant species and thus classified as core, with Contracaecum sp. as the satellite and other species as secondary species. The spatial distribution of infection with Ergasilus sp. and Contracaecum sp. showed a typical pattern of aggregate distribution. The sex of the host did not influence parasitic infections, but infection with Ergasilus sp. showed a positive and significant correlation with biometric and epidemiologic parameters, whereas infection with Contracaecum sp. was correlated only with prevalence and abundance.

A multiproxy record of Holocene environmental changes from the northern Kuril Islands (Russian Far East)

Diatom, rock magnetic, geochemical, and lithological studies of a sediment core from Paramushir Island (northern Kuril Archipelago) trace environmental shifts from bog to salt-water lagoon to freshwater lake over the past 10,000 14C BP. Organic-rich mesic landscapes dominated the southern island until ~8200 14C BP. Transgression of the Sea of Okhotsk onto the island began sometime after 8200 14C BP, resulting in the formation first of a salty (~8200–5700 14C BP) then a brackish (~5700–5200 14C BP) lagoon. With lowering of sea level after 5200 14C BP, a freshwater lake formed, which has remained to the present day. This history parallels regional trends in the Russian Far East, where maximum sea levels occurred between ~8000 and 4600 14C BP, peaking at ~6400 14C BP. Sandy levels within the lake core suggest four intervals of aeolian activity (~4900–4800 14C BP; 4300–3800 14C BP; 3200–3000 14C BP; 1900–900 14C BP), perhaps related to drier than present climates. Palynological data indicate a dominance of Pinus pumila–Duschekia kamtschatica shrub tundra in the lowlands ~8200–5800 14C BP, marking the Holocene thermal maximum. This vegetation contrasts to modern, which established ~5800 14C BP and is a mix of coastal meadow, Betula–Salix low shrub tundra, and scattered Pinus and Duschekia thickets. The palynological record shows little response to mid-to-late Holocene climatic fluctuations except for a decrease in Pinus shrubs perhaps caused by changes in snow cover and/or summer temperature during the Little Ice Age.

Description and phylogenetic position of Corlissina maricaensis gen. nov., sp. nov. (Karyorelictea, Geleiidae), a novel interstitial ciliate from Brazil, with redefinition of the family Geleiidae

Corlissina maricaensis gen. nov., sp. nov. was obtained from samples of sediment collected in a brackish lagoon of Maricá city, Rio de Janeiro state, Brazil. The morphological description was based on live observations, after protargol staining, and scanning electron microscopy. The novel species has a cylindrical body shape that is slightly contractile, 230-550 × 35-65 μm, a cytoplasm with many globular inclusions, one row of irregular cortical granules between each somatic kinety, approximately 40-62 somatic kineties, two globular macronuclei measuring 9-24 μm and one micronucleus of approximately 4-9 μm. A subapical oral cavity was approximately 20-80 × 9-25 μm, with an adoral zone on the left side of the buccal field, which was composed of 32-60 polykineties and a paroral at the right side that was composed of 40-57 short polykineties. The new genus is distinguished from other geleiids by a loop-shaped posterior end of the paroral ciliature, made up of two rows of short polykineties, and the oralization of the central superior kinety (K0i), forming a row of dikinetids that borders the adoral zone internally, followed by several rows of monokinetids. In the phylogenetic analyses, the novel species was recovered as the sister group of Parduczia orbis with full support values based on 18S rRNA gene sequences. This work also indicates some problems in the definitions of the Geleiidae and proposes a new diagnosis for this karyorelictid family.

Impacts of the 2011 Tsunami on Sediment Characteristics and Macrozoobenthic Assemblages in a Shallow Eutrophic Lagoon, Sendai Bay, Japan.

A huge tsunami is one of the greatest disturbance events in coastal benthic communities, although the ecological consequences are not fully understood. Here we examined the tsunami-induced changes in the sediment environment and macrozoobenthic assemblage in a eutrophic brackish lagoon in eastern Japan. The 7.2-m-high tsunami completely replaced muddy sediment with drifting sea sand throughout the lagoon, leading to the drastic changes in quantity and quality of sedimental organic matters, sulfide contents, and sediment redox condition. Intensive physical stress devastated the benthic community, but the disappearance of sulfidic muddy bottoms significantly improved the habitat quality for macrozoobenthos. The re-established macrozoobenthic community after 5 months was characterized by (1) a 2-fold higher total density, but sharp declines in species richness, diversity, and evenness; (2) an increased density of opportunistic taxa (e.g., polychaete Pseudopolydora spp. and amphipod Monocorophium uenoi) in newly created sandy bottoms; and (3) disappearance of several dominant taxa including bivalves and chironomid larvae. These findings indicate that the sensitivity and recovery potential of macrozoobenthos were highly taxa-specific, which was closely related to the taxa’s ecological characteristics, including tolerance to physical disturbance, life-history traits, and life form. Our data revealed the rapid recolonization of opportunistic macrozoobenthos after a huge tsunami, which would contribute to the functional recovery of estuarine soft-bottom habitats shortly after a disturbance event.

Trends in a satellite-derived vegetation index and environmental variables in a restored brackish lagoon

We evaluated relative influence of climatic variables on the plant productivity after lagoon restoration. Chilika Lagoon, the largest brackish lake ecosystem in East Asia, experienced severe problems such as excessive dominance of freshwater exotic plants and rapid debasement of biodiversity associated with decreased hydrologic connectivity between the lagoon and the ocean. To halt the degradation of the lagoon ecosystem, the Chilika Development Authority implemented a restoration project, creating a new channel to penetrate the barrier beach of the lagoon. Using a satellite-derived normalized difference vegetation index (NDVI) dataset, we compared the trend of vegetation changes after the lagoon restoration, from April 1998 to May 2014. The time series of NDVI data were decomposed into trend, seasonal, and random components using a local regression method. The results were visualized to understand the traits of spatial distribution in the lagoon. The NDVI trend, indicative of primary productivity, decreased rapidly during the restoration period, and gradually increased (slope coefficient: 2.1×10−4, p<0.05) after two years of restoration. Level of seawater exchange had more influences on plant productivity than local precipitation in the restored lagoon. Higher El Niño/Southern Oscillation increased sea level pressure, and caused intrusion of seawater into the lagoon, and the subsequently elevated salinity decreased the annual mean NDVI. Our findings suggest that lagoon restoration plans for enhancing interconnectivity with the ocean should consider oceanographic effects due to meteorological forcing, and long-term NDVI results can be used as a valuable index for adaptive management of the restoration site.

Turkey as a crossroad for Greater Flamingos Phoenicopterus roseus: evidence from population trends and ring-resightings (Aves: Phoenicopteridae)

The Greater Flamingo Phoenicopterus roseus is a waterbird commonly found in saline and brackish lagoons throughout the Mediterranean Region. We have gathered existing data on Greater Flamingos in Turkey and carried out field surveys to present the most up to date information on wintering (1999–2014) and breeding (1969– 2014). The wintering population of flamingos shows an increasing trend with 54,947±20,794 individuals mainly concentrated in the Gediz, Büyük Menderes and Çukurova deltas, respectively. Breeding attempts were recorded in at least seven wetlands in Turkey in the past, yet after 1999 most of the colonies were abandoned due to basin scale intensive water management practices in Central Anatolia. Currently, only Tuz Lake and Gediz Delta are used as regular breeding sites, while breeding has been recorded sporadically in Acıgöl and Akşehir Lakes. The breeding colony of Tuz Lake is of prime importance at the Mediterranean scale, with the number of young chicks in 2011, 2012 and 2013 accounting for the highest number of fledglings in the Mediterranean Region and West Africa (18,418, 20,274 and 20,292 respectively). Finally, building upon the previous findings about Turkey and the western Mediterranean metapopulation links, recent resightings of Turkish flamingos (despite the limited numbers) confirm post-fledging and natal dispersal reaching the western Mediterranean Basin and West Africa. Flamingos from Turkey were also found to disperse to Israel and to a region outside the known flyways of the western Mediterranean and West African flamingos (i.e. to Israel and UAE). Thus, Turkey, due to its geographic position, appears to be a crossroad between the western and eastern Mediterranean Region and southwest Asia.

Conodont biofacies of the Taghanic transgressive interval (middle Givetian): Polish record and global comparisons

Abstract Conodont biofacies of the Lublin and Łysogóry–Radom basins in SE Poland have been analysed in five cored borehole sections in a narrow interval of the middle Givetian Polygnathus ansatus Zone, corresponding to the global Taghanic transgression. Assemblages exhibiting various proportions of dominant genera, Icriodus (I) and Polygnathus (P), as well as particular P species and a few accessory taxa, reflect both temporal transgression dynamics and lateral facies changes. The latter comprise transition from a brackish lagoon with intermittent open-marine influence, to a carbonate shoal and offshore marly shelf, generally characterized by P–I biofacies, but with a varying proportion of constituent genera and polygnathid species. Comparison of the Polish record with stratigraphically well-constrained, quantitative biofacies evidence worldwide allowed the construction of a 2D nearshore–offshore model for the Euramerican epicontinental faunas connected with Taghanic transgressive facies. The I/P ratio has a diagnostic value for specific sub-environments (very nearshore/shallow-water and drowned platform) but for other settings the Polygnathus ansatus to Polygnathus linguiformis ratio appears more useful. The Moroccan faunas display specific biofacies patterns tentatively explained by different climatic conditions. The conodont biofacies concept has a limited application for palaeogeographically isolated settings, including pelagic-oceanic areas of microcontinents or submarine rises. In other cases (Eastern Australia), palaeobiogeographical bias precludes direct comparisons with the Euramerican model.

Feeding, Growth, and Dispersal of Hatchery-reared Spotted Halibut Verasper variegatus Released in a Shallow Brackish Lagoon: Matsukawa-ura, Northeastern Fukushima, Japan

Feeding, Growth, and Dispersal of Hatchery-reared Spotted Halibut Verasper variegatus Released in a Shallow Brackish Lagoon: Matsukawa-ura, Northeastern Fukushima, Japan

Estimating the impact of air temperature and relative humidity change on the water quality of Lake Manzala, Egypt

By the late eighties the problem of climate change and its possible impacts had become an issue of global concern. Climate variables play an important role in controlling the water circulation and the water quality of lakes either as freshwater reservoirs, or as brackish lagoons. In Egypt, Lake Manzala is the largest and the most productive lake of the northern coastal lakes. In this study, continuous measurement data from the Real Time Water Quality Monitoring stations in Lake Manzala was statistically analyzed to determine the regional and seasonal variations of the selected water quality parameters in relation to changes in two climate variables: air temperature and relative humidity. Simple formulas are elaborated using the DataFit software to predict the selected water quality parameters of the Lake including Power of Hydrogen (pH), Dissolved Oxygen (DO), Electrical Conductivity (EC), Total Dissolved Solids (TDS), Turbidity, and Chlorophyll as a function of air temperature and relative humidity. It was revealed that there is a measured relation between air temperature and relative humidity and the pH, DO, EC and TDS

Opportunities and constraints for managed retreat on exposed sandy shores: Examples from Emilia-Romagna, Italy

Managed retreat is rarely implemented on exposed sandy coasts because of public interest in beach recreation and the great human-use value of existing beaches and dunes. The feasibility of retreat on the sandy coast of the Adriatic Sea in the Region of Emilia-Romagna was evaluated at a site with a single user facility (a beach concession) backed by public parkland. A conceptual scenario of changes to landforms and habitats was developed for the retreat option. Interviews with key stakeholders revealed perceptions of alternatives for addressing erosion and flooding by managed retreat or by protecting existing features in place.The beach concession occupies a segment of shore between an eroding (−9.3 m yr−1) washover barrier updrift and an accreting beach downdrift. Landward of the concession is a portion of the Po Delta Park, consisting of a brackish lagoon and marsh and an artificially-created freshwater lake. Shore protection projects have maintained the concession and the integrity of a dike protecting the lake. Allowing retreat to occur would cause (1) loss of the concession in its present location; (2) erosion of the dike, converting the lake to brackish habitat; and (3) migration of the shoreline to a pine forest, campground and residences that are now 500 m from the shoreline. Freshwater and pine forest habitat would be lost, but salt water wetland and pioneer coastal species would be restored. The beach and campground could still be used as the shoreline migrates inland, but with less fixed infrastructure. Landward facilities could be protected by a ring dike.At issue is whether normally dynamic and short-term landforms and habitats should be protected as static features in perpetuity and whether human actions should be taken to protect human-created nature (lake, pine forest) against natural evolutionary processes. Stakeholders indicated that managed retreat should occur eventually but existing features should be protected now. The retreat option is compatible with Regional ICZM plans, but differs from the standard engineering designs actually suggested for implementation. The benefits of managed retreat on exposed sandy shores can only be presented in conceptual terms until demonstration projects provide concrete answers, so it is not surprising that the undocumented benefits of a more dynamic shoreline have little appeal relative to maintaining the status quo.

Harpacticoida (Copepoda) fauna and the taxocenes structure of brackish lagoons and estuaries of the Russian far east

On the basis of original data and literature sources, the species composition of Harpacticoida (Copepoda) in the plankton of the brackish waters of four Far Eastern regions was described: Khabarovsk krai, Sakhalin Island, Kamchatka Peninsula, and the Commander Islands. The compiled list includes 32 harpacticoid species of 22 genera and 10 families. The representatives of the typical brackish families Canthocamptidae and Ectinosomatidae account for about one-third of the total. Six of the species are new to science: 4 species of Halectinosoma, Amphiascus sp. 1, and Schizopera sp. 1. Cosmopolitan species constitute the major portion of the fauna (38% of the total number), while a smaller proportion is typical of endemics (25%), as well as species with the arctic (12%), tropical (9%), and North American (9%) types of areas. There are 17 types of harpacticoid taxocenes of the observed water bodies. Also, the influence of the salinity and temperature on these species complexes was characterized. The hypotheses about the cosmopolitanism of the brackish water fauna and the intrazonality of the estuarine harpacticoid taxocenes structure were tested. It is shown that the structure of the genera dominance in the taxocenes allocated for the temperature latitudes of the Far East demonstrates significant similarity with the arctic and tropical regions.

Spatio-temporal pattern of community development in dredged material used for habitat enhancement: A study case in a brackish lagoon

Dredged material is a potential resource for beneficial use for create/improve subtidal habitats. In a northwestern Adriatic lagoon, dredged sand was placed in inner areas with the management objective of improving the characteristics of the muddy areas being recharged. With this study we investigated the recolonization dynamics of benthic communities following the placement of dredged sand in a microtidal lagoon. The disposal of dredged sand had an immediate and negative effect on resident fauna. After an initial reduction, benthic communities followed different recovery pathways. One year after disposal, we recorded an almost complete recovery of the benthic invertebrates in terms of univariate parameters. Despite multivariate analyses still showed significantly different community structures, the trajectories of recovery for disposal areas converged towards the same basin of attraction of control areas. The ecological quality of sites, assessed with benthic indices, did not improve, thus no new beneficial habitat was created for macrobenthos.

Depositional environments, sediment characteristics, palaeoecological analysis and environmental assessment of an internationally protected shallow Mediterranean lagoon, Gialova Lagoon – Navarino Bay, Greece

ABSTRACTThis study presents sedimentological, palaeoecological and geochemical data from a shallow Mediterranean coastal lagoon which has been severely influenced by human intervention over the last 70 years. The Gialova Lagoon is protected by international conventions and is listed in the Natura 2000 European Community Network as Special Protection Area (SPA) and Site of Community Importance (SCI). The spatial variability of sediment characteristics such as grain size, total organic carbon (TOC) and moment measures, mean, sorting, kurtosis and skewness were calculated. Moreover, micro- and macrofossil and sediment geochemical analyses were carried out on six gravity core samples. Study of the above parameters indicates that the anthropogenic impact and intervention are reflected in the micro- (ostracods, foraminifera, charophytes) and macrofossil (molluscs) taxa corresponding to different depositional environmental facies, representing a brackish lagoon with the influence of (a) fresh water inflow, (b) shallow marine environment and (c) hypoxic and dystrophic conditions. The geochemical characteristics and the calculation of the degree of sediment contamination using enrichment factors (EF), contamination factors (Cif) and the index of geo-accumulation (Igeo) indicate a recent relative improvement of the lagoon towards the upper layers of the gravity cores, rendering the lagoon as unpolluted to moderately polluted. This combinatorial study of sediment geochemical characteristics, as well as the downcore micro- and macrofossil assemblages, can be considered as a baseline for future monitoring in accordance with European Union directives, and for any future engineering interventions for the lagoon environmental maintenance and conservation; as this is the first time that geochemical and downcore palaeoecological data have been presented from this lagoon.