Rare charophytes in Scotland's coastal saline lagoons

Summary

Recently collected data comparing the distribution and performance of the rare lagoonal charophyte Lamprothamnium papulosum across a number of UK coastal lagoon sites, including nine sites in the Western Isles, is presented. The surveys revealed that the species occurred over a wide range of salinities but was absent from sites with high phosphorus concentrations. The sites in the Western Isles held the most extensive populations and were least threatened by nutrient pollution. The discovery of two other endangered and vulnerable charophytes of brackish water, Tolypella nidifica and Chara baltica, at two of the Western Isles sites further highlights the importance of Scotland's saline lagoon resource. The use of the autoecological data on salinity and nutrient conditions for supporting Biodiversity Action Plan implementation for Lamprothamnium papulosum and for saline lagoon conservation in general is considered. Status summaries for all the charophyte species of brackish water recorded in Scotland are also provided.     

Methodologies for measuring and modelling change in coastal saline lagoons under historic and accelerated sea-level rise,Suffolk coast,eastern England

Thorough assessment of vulnerable coastal habitats, impacted by sea-level rise and anthropogenic pressures, requires both the accurate establishment of the evidence base for current status and scientifically-informed forward planning of expected future status. Coastal saline lagoons are transitional, ephemeral habitats of considerable conservation interest; under European legislation their status requires on-going maintenance of ‘favourable status’. Over decadal timescales, the seaward barriers that enclose saline lagoons migrate progressively landwards. Geo-referenced and digitised historic maps and aerial photographs are used to create a detailed trajectory of barrier migration and loss of lagoon area for three saline ‘broads’ on the rapidly retreating coastline of Suffolk, eastern England. The SCAPE shoreline response model is then employed to extend this trajectory, under a range of sea-level rise scenarios, to 2050 and 2095 and to predict saline lagoon ‘time to extinction’. Loss rates are likely to accelerate considerably after 2015 and a fundamental revision of UK saline lagoon creation targets is urgently required. The approach is generic and could be used to assess the evolutionary trajectories for other vulnerable coastal habitats, under a range of near-future environmental change scenarios.     

Proposals for macrophyte restoration in eutrophic coastal lagoons

Based on the comparison of environmental requirements forRuppia cirrhosa andPotamogeton pectinatus growth, macrophyteversus phytoplankton biomass and production features, and differences in hydrological and nutrient balances between Tancada lagoon (where macrophytes form dense beds) and Enca?izada lagoon (with no macrophytes at all), several proposals for macrophyte restoration are presented. The highest photosynthetic efficiency ofR. cirrhosa takes place at high irradiance and it grows over a wide range of salinity.P. pectinatus is better adapted to lower light intensity and salinity thanRuppia. R. cirrhosa transplanted from Tancada to Enca?izada was successful in enclosures, where light availability increased (μ=0.013 cm⁻¹), but not in open waters where light extinction coefficient was 0.032 cm⁻¹. Phytoplankton biomass (0.11–2.15 g C m⁻²) is much lower than macrophyte biomass (16–200 g C m⁻²) in Tancada lagoon. However, phytoplankton production (165 g C m⁻² yr⁻¹ in Tancada, 480 g C m⁻² yr⁻¹ in Enca?izada) is the same order of magnitude as macrophyte production (244–467 g C m⁻² yr⁻¹). Turnover rates are 0.3–0.9 day⁻¹ for phytoplankton and 1.2–2.5 yr⁻¹ for macrophytes. Phytoplankton and inorganic particles are responsible for high turbidity of the water in Enca?izada lagoon. Phytoplankton blooms in Enca?izada lagoon are supported by high freshwater inflows from rice field drains from May to November. The Q_s (seawater discharge)/Q_F (Freshwater discharge) ratios are, respectively, 0.24 and 0.48, which denotes a higher seawater influence in Tancada than in Enca?izada lagoon. Decreasing freshwater inputs to Enca?izada lagoon both in May and November thus allowing greater inputs of sea water, is proposed as the most effective way to restore this eutrophic coastal lagoon. The objective being to reduce nutrient loadings to the lagoon and phytoplankton in order to favour macrophyte re-colonization.     

Insights into the harmful algal flora in northwestern Mediterranean coastal lagoons revealed by pyrosequencing metabarcodes of the 28S rRNA gene

This study investigated the genetic diversity of phytoplankton communities in six shallow lagoons located on the French coast of the northwestern Mediterranean Sea that represented a trophic gradient ranging from oligotrophic to hypereutrophic. The phytoplankton communities were sampled once a month from spring (May) to the beginning of autumn (September/early October) in 2012 and fractionated by size. Metabarcodes were generated from cDNAs by targeting the D1-D2 region of the 28S rRNA gene and pyrosequenced using Roche 454 technology. Examination of the annotated barcodes revealed harmful algal species not previously documented in these lagoons. Three ichthyotoxic species belonging to Pfiesteriaceae were detected: Luciella masanensis was relatively widespread and abundant in many samples, whereas Pfiesteria piscicida and Stoeckeria changwonensis were found as single barcode sequences. Furthermore, a phylogenetic analysis of barcodes annotated as belonging to Pfiesteriaceae suggested the existence of two previously undescribed clades. The other toxic or potentially harmful dinoflagellates detected through rare barcodes were Dinophysis acuminata, Vulcanodinium rugosum, Alexandrium andersonii and A. ostenfeldii. The two most abundant dinoflagellate taxa were Gymnodinium litoralis and Akashiwo sanguinea with respect to sequence numbers. Four diatom species from the genus Pseudo-nitzschia that potentially produce domoic acid were identified (P. galaxiae, P. delicatissima, P. brasiliana and P. calliantha). These observations are discussed in terms of the literature and monitoring records related to the identified taxa in this Mediterranean area.     

Regime shifts in vegetation composition of Baltic Sea coastal lagoons

Vegetation communities, morphometric and water quality variables were sampled in 62 undisturbed coastal lagoons along a natural land-uplift gradient in the northern Baltic Sea. The lagoons had a morphological inlet threshold reflecting habitat isolation (i.e. the diminished connectedness of the lagoon to the sea) and located in different parts of the archipelago (corresponding to altering wave exposure). We used indirect multivariate methods to find changes in vegetation composition, and axes derived from the analyses were used in correlation and stepwise multiple regression analyses together with environmental variables. Habitat isolation proved to be the strongest predictor for vegetation composition. To identify significant change-points we used a method, which detects regime shifts by accounting for differences in chronological series and gives a regime shift index. Significant shifts in habitat isolation, average depth and total nitrogen were followed by shifts in species variables (i.e. dominant species, cover and species richness) and salinity, total phosphorus and turbidity. Of the species, especially Chara tomentosa showed a shift of high magnitude. Also a shift in wave exposure mirroring position of lagoons in the archipelago structured the species, but this division was seen only for less isolated lagoons. Our results suggest that lagoons are primarily structured by habitat isolation forming two structurally different regimes: one of less isolated lagoons dominated by a diverse array of vascular plants and marine algae of both outer and inner archipelago characters, and one with isolated lagoons dominated by high vegetation cover and dominance of Chara. In addition, vegetation seemed to stabilize water quality in the isolated regime by reducing turbidity and phosphorus, indicating a potential feed-back mechanism and a shift in structuring disturbances from abiotic to biotic factors with habitat isolation.     

The role of microphytobenthos on shallow coastal lagoons: a modelling approach

Ria Formosa is a Region of Restricted Exchange given its limited connection to coastal water circulation. Furthermore, it is subject to several anthropogenic activities that can lead to an increase in nutrients and potentially to eutrophication. Previous studies have shown the importance of the benthic compartment, specifically the microphytobenthos (MPB) in this shallow coastal lagoon. The dCSTT–MPB model [new version of the dynamic Comprehensive Studies Task Team (dCSTT) model] here described couples the benthic and pelagic compartments. Due to the shallowness of the system, the benthic microalgae are one of the most important primary producers of the system. Preliminary results of the model show a large biomass of benthic microalgae, which strongly influences the pelagic chlorophyll concentration by resuspension. However, algae concentrations in the water column are relatively small due to the high flushing rate of the lagoon. The MPB community is mainly supported by nutrients in the pore water. A sensitivity analysis (SA) has revealed that the factors associated with the benthic compartment were the most important and sensitive to changes. Porosity, benthic chlorophyll recycling, loss of MPB due to grazing and the yield of microphytobenthic chlorophyll from nitrogen were some of the most sensitive parameters, as well as the ones associated with decay of particulate organic nitrogen. The development of our dCSTT–MPB model has itself provided insights into benthic function.     

Characterization of the waterbird communities wintering in Tunisian coastal lagoons

This article aims at studying wintering waterbirds in Tunisian coastal lagoons in order to support effective conservation measures. Species number and abundance of wintering waterbirds were assessed in January, each year from 2002 to 2007, in 10 lagoon sites belonging to four different lagoon systems. We counted 76 species and on average more than 120,000 birds per year, which represented more than 25% of the national population sizes. The most abundant taxonomic groups were waterfowls and waders, which also represented the highest species number. In general, the six most abundant bird species comprised collectively more than 77% of all birds counted. Considering all the studied lagoon systems collectively, for 13 species the lagoon systems should be considered as of international importance according the Ramsar Convention as they support regularly more than 1% of the populations. Only the lagoon system of the North held regularly more than 20,000 birds. The species abundances and species richness varied significantly among year and among lagoon systems. Based on our results we proposed priority conservation measures, these ecosystems being of major importance for wintering birds, at both national and international level.     

Beyond the Mediterranean to global observations of coastal lagoons

The United Nations has begun addressing the detection and prediction of global and large-scale change through the development of observing systems. The three observing systems are the Global Climate Observing System (GCOS); the Global Ocean Observing System (GOOS); and the Global Terrestrial Observing System (GTOS). Each of these is designed to be a ‘8user-driven, end-to-end’ system, providing measurements of selected variables and indicators, management and communication of these, and their analysis and synthesis into products for users. The interface between the land and ocean provides complexities that affect the capabilities of the three global observing systems. Understanding the complex interactions between natural and human systems at various scales is central to successful management of the coast in the face of change. Both GOOS and GTOS have organized initiatives for the coast with the GOOS initiative (CGOOS) being more developed. CGOOS is built upon a global network, which focuses on a limited number of phenomena and their associated variables, and regional programs that contribute to the global network and focus on other phenomena. CGTOS (coastal GTOS) has identified a few key phenomena for the development of the future mature system. These phenomena are linked to a framework that incorporates socio-economic variables into the program. To establish proof of concept and early success by CGTOS, four priority products have been identified that address (1) transport of materials, (2) functional typology, (3) integrated assessments of cultural and conservation sites, and (4) assessment of human populations and land use and land cover. The coastal observing systems are in the stages of developing implementation plans and should be operable in coming years.     

Fish species richness decreases with salinity in tropical coastal lagoons

Aim To analyse the relationship between fish species richness and salinity, and to provide a simple linear model for fish diversity trends across salinity gradients in a tropical coastal lagoon that can be compared with other similar ecosystems and other communities. To reinforce our conclusions, the salinity–fish richness relationship was investigated at different spatial scales (sampling station, set of stations and whole lagoon) and for two different periods, separated by 18 years. Location The Terminos coastal lagoon, a shallow tropical lagoon (mean maximum depths ranging between 3.5 and 4.5 m), is located in the southern Gulf of Mexico (18.5–18.8° N, 91.3–91.9° W). The lagoon is 70 km long and 30 km wide, with a surface area of 1700 km². Methods Fish sampling, individual identification to the species level, and environmental variable measurements were carried out monthly at 17 sampling points. Multiple regression analysis with a backward selection procedure was used to relate fish species richness to environmental variables. Other statistical techniques, including cluster analysis and ancova , were applied to experimental data surveys. Results Among the different environmental variables, salinity was significantly and consistently related to fish species richness, whatever the period and the scale of observation. We found mainly significant negative correlations (P < 0.05) between fish species richness and salinity when sampling stations were analysed individually, and particularly for the river runoff zones with high variation in salinity throughout the year. For the entire lagoon, robust negative linear models were observed when fish species richness was organized into salinity ranges, with salinity explaining c. 8% of the variation in mean fish species richness (in a multiple regression analysis; 63–93% when considered in isolation). Main conclusions In the Terminos lagoon the relationship between fish species richness and salinity is mainly negative on any spatial scale. This result may be due partially to the penetration of freshwater fishes into estuarine areas following freshwater discharges, and partially to the dominance of estuarine taxa more able to tolerate low than high salinity values. Finally, we suggest that the ‘realized’ ecotone, where species from different origins really mix, is situated between 5 and 10‰, corresponding to the highest fish richness.     

Hydrographic,geomorphologic and fish assemblage relationships in coastal lagoons

In this study, 40 Atlanto-Mediterranean coastal lagoons were analyzed in order to evaluate the extent to which their ecological characteristics depend on hydrographic, trophic or geomorphologic features. Fish species richness increases with lagoon volume and the openness parameter, which characterizes the potential influence of the sea on general lagoon hydrology and is related to the total transversal area of the inlets, which connect the lagoon to the sea. On the other hand, the number of species decreases exponentially with the phosphate concentration in water. The fishing yield increases with the chlorophyll a concentration in the water column and exponentially with shoreline development. With respect to the fish assemblage composition, geomorphologic features alone explain 22% of the variance in the canonical analyses and an additional 75% when including the hydrographic and trophic characteristics of the lagoon, the latter on its own explaining only 3% of the observed differences.     

Distribution of lichen flora on South Korea

After an overview on the temporary situation of the lichenology in South Korea, localities of 95 macrolichen taxa are reported for South Korea. In this revised lichen flora of South Korea, 16 species are apparently new to the territory. Voucher specimens have been deposited in the Korean Lichen Research Institute (KoLRI) at Sunchon National University in Korea, and duplicates have also been donated to the National History Museum and Institute, in Chiba, (CBM) Japan.     

Bacterial interactions in the rhizosphere of seagrass communities in shallow coastal lagoons

Rooted phanerogam communities in the shallow intertidal and subtidal coastal zone represent productive and healthy ecosystems. Inorganic nutrients are assimilated into seagrass biomass. Much of the organic matter resulting from moribund seagrass is rapidly mineralized, principally by bacteria. The microbial community of the rhizosphere is also highly active due to the supply of organic matter released during photosynthesis. This active sediment community plays an important role through carbon, nitrogen and phosphorous cycling in maintaining the stability and productivity of seagrass meadows. Over the last two decades, however, seagrass meadows in European coastal areas have declined due to increasing pollution. As eutrophication advances a trasition occurs from rooted phanerogram dominated communities to planktonic algal blooms and/or cyanobacterial blooms. Such changes represent the decline of a stable, high biodiversity habitat to an unstable one dominated by a few species. These changes of community structure can occur rapidly once the internal nutrient and organic matter control cycles are exceeded. A field investigation was undertaken to establish the spatial distribution of bacterial populations of Zostera noltii colonized and uncolonized sediment in the Bassin d'Arcachon, France. Bacteria were enumerated using both plate count and MPN techniques for different functional groups as well as determining the total bacterial populations present. Nitrogen fixation, ammonification, sulphate reduction rates, as well as alkaline phosphatase activity were also determined. Colonization of the Z. noltii roots and rhizomes was studied by light and scanning electron microscopy. Results confirmed that higher bacterial populations were present in the rhizosphere of Z. noltii compared to uncolonized sediments. Furthermore, electron microscopy identified the rhizome as the main site of colonization for a diverse range of morphological groups of bacteria. Sulphate reducing bacteria were identified as the key group of bacteria involved in N-fixation in the rhizosphere of Z. noltii. The data will be discussed in relation to the role played by the rhizosphere microflora in supplying and mobilising nutrients in Z. noltii.     

New materials for lichen flora from Xizang

In the present paper, ten lichen species from Xizang are reported. Three of them are new species and three new infraspecific taxa. One species and one variety are made as new combinations. The apothecium of Lethariella cashmeriana Krog is described for the first time. This paper also deals with nomenclatural problems of certain species. The authors found that the specific epithets of Gyrophora hypococcina Jatta (A. Zahlbruckner, 1927, 1934) and G. hypocrocina Jatta (A. Zahlbruckner, 1930) were either orthographic or typographic errors for G. hypococcinea Jatta (1902) (original spelling). According to the Article 73:1 of the International Co de of Botanical Nomenclature [Leningrad Code (1978)],. the epithet (hypococcinea) must be retained and the name Umbilicaria hypococcinea (Jatta) Llano must, therefore be used substituting for U. hypococcina (Jatta) Llano (1950; Lu, 1959). The authors wish to express their sincere appreciation to Prof. T Ahti and Dr.O. Vitikainen (H) and Dr. Roland Moberg (UPS) for the loan of type specimens.     

Integrated modelling in coastal lagoons: Sacca di Goro case study

A coupled 3D hydrodynamic-biogeochemical model was developed and implemented for the Sacca di Goro coastal lagoon. The model considers nutrient and oxygen dynamics in water column and sediments. Among the biological elements, phytoplankton, zooplankton, bacteria, Ulva sp. and commercial shellfish (Tapes philippinarum) were taken into consideration. Nutrients fluxes from the watershed and open sea, as well as atmospheric inputs, heat flux, light intensity and wind shear stress at the water surface constituted the model forcing functions. The comparison of numerical results with available measurement data indicated that the model was able to capture the essential dynamics of the lagoon. This model has also been used to estimate clam productivity and its impacts on water quality and lagoon properties. Guest editors: A. Razinkovas, Z. R. Gasiūnaitė, J. M. Zaldívar & P. Viaroli European Lagoons and their Watersheds: Function and Biodiversity     

Heterotrophic microbial activity and organic matter degradation in coastal lagoons of Colombia

In this study we measured the community respiration and the bacterial respiration as part of the overall degradation process of organic material. Additionally, the turnover rates of the pools of dissolved free glucose and acetate as representatives of the fraction of easily degradable low molecular organic solutes were determined. The study was performed in several coastal lagoons of the "Outer Delta of the Río Magdalena" in northern Colombia. The lagoons can be separated into two groups: The first group contains highly productive brackish lagoons with chl a concentrations ranging from 62-130 micrograms/l. The second group consists of less productive freshwater lagoons with chl a between 5.5-19 micrograms/l. Turnover rates of glucose and acetate were very fast in the highly productive lagoons resulting in turnover times of less than 20 min for both compounds. In the less productive systems the cycling of glucose and acetate was much slower. Here the mean values of the turnover times were 2 hr for glucose and 1.5 hr for acetate. The rates of bacterial DNA-formation measured as thymidine incorporation differed significantly between both groups of lagoons, being very high (1.86-2.76 nmol/l/hr) in the highly productive and relatively low (0.073-0.55 nmol/l/hr) in the less productive group. Water column community respiration ranged between 122 and 16 micrograms C/l/hr with means of 88 micrograms C/l/hr in the highly and 19 micrograms C/l/hr in the less productive group. In the first group the mean values of the bacterial contribution to community respiration amounted to 37% and in the second group to 18%. The bacterial respiration was determined in an indirect way via bacterial biomass production and assuming a growth efficiency of 50%. It is discussed whether this relatively high growth efficiency allows reasonable results in both groups of lagoons.     

The fate of organic matter sources in coastal environments: a comparison of three Mediterranean lagoons

Trophic processes in coastal lagoons are strongly influenced by freshwater inputs and water exchanges with the sea. In recent years, stable isotope analysis has become a widespread and reliable method for the examination of trophic structure over time and space, also in complex ecosystems such as coastal lagoons. Stable isotopes of carbon and nitrogen were studied in primary producers and consumers to identify organic matter source pools from terrestrial, benthic and pelagic environments and to characterise the trophic structure in three Mediterranean coastal lagoons (Lake Fusaro, the Lake of Sabaudia and Stagnone di Marsala). The results highlighted the negligible importance of terrestrial production to higher trophic levels in all the ecosystems investigated. Consumer dependence on benthic and pelagic organic matter showed high variability: overall macroalgae were at the base of the food web in Lake Fusaro and the Lake of Sabaudia, while mixed sources (seagrass detritus, epiphytes, macroalgae and sedimentary organic matter) appeared to be the major baseline food resource in the Stagnone di Marsala. We have found evidence for significant changes in the trophic structure in these Mediterranean coastal lagoons and such differences may be triggered by differential environmental features (e.g. freshwater inputs and hydrodynamic regime). Guest editors: A. Razinkovas, Z. R. Gasiūnaitė, J. M. Zaldivar & P. Viaroli European Lagoons and their Watersheds: Function and Biodiversity     

Helminth communities in eels Anguilla anguilla from Adriatic coastal lagoons in Italy

The composition and diversity of the total and intestinal component and infra-communities were determined in eels Anguilla anguilla from three shallow lagoons on the Adriatic coast of Italy to determine whether the helminth communities would differ in composition and structure from those in eels from lagoons on the Tyrrhenian coast. The lagoons differed in respect of their management regimes and the extent of freshwater influx. Both freshwater and marine species of helminths were found in the eels in all three lagoons, but the freshwater component was richer in Valle Figheri. A suite of three digenean eel specialist species occurred in all three lagoons, of which any two members dominated each community. This conferred a high degree of similarity between the communities of the three lagoons. The same three species also dominated helminth communities in eels in lagoons along the Tyrrhenian coast of Italy, and compositional similarity levels were similar within and between western and eastern groups. Species richness was higher in the component communities of the eels of the Adriatic lagoons when compared to the Tyrrhenian ones, but diversity and dominance indices were of a similar order of magnitude and range. Intestinal helminth communities were richer and more diverse in two of the Adriatic lagoons because the proportion of eels with zero or one helminth species was, unusually, in the minority. It was nevertheless concluded that infracommunity structure was similar in eels from both western and eastern lagoons and that the hypothesis that it would differ in Adriatic lagoons could not be supported. The findings provide further evidence of the similarity in composition and structure of helminth communities in eels from coastal lagoons throughout Europe.