Brackish Coastal Lagoon Research Articles

Screening for White Spot Syndrome Virus (WSSV) in pink shrimp (Penaeus paulensis) from Rocha Lagoon, Uruguay

Penaeus paulensis (pink shrimp) is an important resource for small-scale fisheries in the brackish coastal lagoons of Uruguay. No viral diseases have been detected in shrimp populations in the Uruguayan territory. The presence of viral pathogens, such as White Spot Syndrome Virus (WSSV) and Infectious Hypodermal Haematopoietic Necrosis Virus (IHHNV) in wild shrimp populations has been previously reported in Brazil and Argentina.We investigated the presence of WSSV in wild populations of penaeid shrimp from Rocha Lagoon, Uruguay. We sampled 70 specimens of juvenile P. paulensis and assessed the presence of these viral pathogens using nested PCR and histology. Gill tissue from the 70 samples was divided into 14 pools of 5 individuals for DNA extraction and PCR analysis. We also retested each pooled sample individually. The nested PCR procedure described in the WOAH aquatic animal manual was used. A subset of 20 individual specimens were also processed using standard histological techniques.The results showed that WSSV was not detected in the pooled or individually tested samples. We found no evidence of the presence of the viral genome or gill lesions in the samples analysed. This indicates that the fishery is still likely to be free of WSSV infection. The procedures and information generated can be used as a baseline study for future implementation of surveillance programmes in the country.

Cyanobacterial Genomes from a Brackish Coastal Lagoon Reveal Potential for Novel Biogeochemical Functions and Their Evolution.

Cyanobacteria are recognised for their pivotal roles in aquatic ecosystems, serving as primary producers and major agents in diazotrophic processes. Currently, the primary focus of cyanobacterial research lies in gaining a more detailed understanding of these well-established ecosystem functions. However, their involvement and impact on other crucial biogeochemical cycles remain understudied. This knowledge gap is partially attributed to the challenges associated with culturing cyanobacteria in controlled laboratory conditions and the limited understanding of their specific growth requirements. This can be circumvented partially by the culture-independent methods which can shed light on the genomic potential of cyanobacterial species and answer more profound questions about the evolution of other key biogeochemical functions. In this study, we assembled 83 cyanobacterial genomes from metagenomic data generated from environmental DNA extracted from a brackish water lagoon (Chilika Lake, India). We taxonomically classified these metagenome-assembled genomes (MAGs) and found that about 92.77% of them are novel genomes at the species level. We then annotated these cyanobacterial MAGs for all the encoded functions using KEGG Orthology. Interestingly, we found two previously unreported functions in Cyanobacteria, namely, DNRA (Dissimilatory Nitrate Reduction to Ammonium) and DMSP (Dimethylsulfoniopropionate) synthesis in multiple MAGs using nirBD and dsyB genes as markers. We validated their presence in several publicly available cyanobacterial isolate genomes. Further, we identified incongruities between the evolutionary patterns of species and the marker genes and elucidated the underlying reasons for these discrepancies. This study expands our overall comprehension of the contribution of cyanobacteria to the biogeochemical cycling in coastal brackish ecosystems.

Ciliate diversity in rodrigo de freitas lagoon (Rio de Janeiro, Brazil) from an integrative standpoint.

The Rodrigo de Freitas Lagoon is a highly eutrophic lacustrine system and has one of the longest histories of exploration and anthropic alteration in Brazil. Despite its relevance, limited studies explored the diversity of micro-eukaryotes in the lagoon. Ciliates (Alveolata, Ciliophora) are overlooked in environmental microbiology, especially in tropical and subtropical ecosystems, resulting in limited knowledge about their diversity and functional relevance in South American habitats, particularly in coastal lagoons. To fill this gap, here we investigated the diversity of ciliates in a brackish coastal lagoon in an urban area of Rio de Janeiro, Brazil, applying and comparing the performance of morphological and metabarcoding approaches. The metabarcoding analysis, based on high-throughput sequencing of the hipervariable region V4 of the 18S rRNA genes detected 37 molecular operational taxonomic units (MOTUs) assigned to Ciliophora, representing only about a half (56.9%) of the diversity detected by microscopy, which counted 65 ciliate morphotypes. The most representative classes in both approaches were Spirotrichea and Oligohymenophorea. The metabarcoding analysis revealed that 35.3% of the ciliate MOTUs had less than 97% similarity to available sequences in the NCBI database, indicating that more than one-third of these MOTUs potentially represents still not represented or undescribed ciliate species in current databases. Our findings indicate that metabarcoding techniques can significantly enhance the comprehension of ciliate diversity in tropical environments, but the scarcity of reference sequences of brackish ciliates in molecular databases represents a challenge to the taxonomic assignment of the MOTUs. This study provides new insights into the diversity of ciliates in a threatened coastal lagoon, revealing a vast array of still unknown and rare ciliate taxonomic units in tropical environments.

Vulnerability assessment of the pink shrimp small-scale fishery to climate change in southwestern Atlantic brackish coastal lagoons (Uruguay)

Assessing vulnerability using semi-quantitative approaches provide an opportunity to analyze conditions of exposure, sensitivity and adaptive capacity of socio-ecological systems concerning climate change drivers and anthropogenic factors. We assessed the vulnerability of the small-scale pink shrimp fishery of Castillos and Rocha lagoons, two coastal Uruguayan ecosystems of the southwest Atlantic, considering social factors and climate change drivers which affect atmospheric-oceanographic conditions regionally and locally. Using a risk approach, we evaluated the ecological system's exposure to environmental drivers. Then we estimated the sensitivity and adaptive capacity of fishers and the local community (social system). High vulnerability found for this fishery results from a combination of large-scale environmental drivers impacting the ecological system, and social factors causing high sensitivity and low adaptive capacity of the social system. High risk level with adverse ecosystem effects triggered by climate change drivers acting on the distribution of this migratory crustacean in the southwest Atlantic region could promote adverse consequences on harvest duration and shrimp catch levels in the Uruguayan coastal lagoons. Fishers and their communities showed high sensitivity to a set of (demographic, economic, governance, cultural and technological) factors. The social system of both lagoons showed a low adaptive capacity to prevent social impacts or to mitigate climate change hazards. A broad set of social indicators was identified in Rocha lagoon to enhance fishers and community resilience, while the indicator set was narrower in Castillos lagoon. Lastly, weak governance, dormant fisheries laws, non-compliance of fisheries regulations and lack of climate early warning monitoring hamper the adaptability of these small-scale fisher communities under global change scenarios. Comparative evaluation of spatial, environmental and social settings between lagoons can offer lessons for upscaling the assessment and adaptation measures to other small-scale fisheries regionally and globally.

Protist taxonomic and functional diversity in aquatic ecosystems of the Brazilian Atlantic Forest.

The Brazilian Atlantic Forest and its associated ecosystems are highly biodiverse but still understudied, especially with respect to eukaryotic microbes. Protists represent the largest proportion of eukaryotic diversity and play important roles in nutrient cycling and maintenance of the ecosystems in which they occur. However, much of protist diversity remains unknown, particularly in the Neotropics. Understanding the taxonomic and functional diversity of these organisms is urgently needed, not only to fill this gap in our knowledge, but also to enable the development of public policies for biological conservation. This is the first study to investigate the taxonomic and trophic diversity of the major protist groups in freshwater systems and brackish coastal lagoons located in fragments of the Brazilian Atlantic Forest by DNA metabarcoding, using high-throughput sequencing of the gene coding for the V4 region of the 18S rRNA gene. We compared α and β diversity for all protist communities and assessed the relative abundance of phototrophic, consumer, and parasitic taxa. We found that the protist communities of coastal lagoons are as diverse as the freshwater systems studied in terms of α diversity, although differed significantly in terms of taxonomic composition. Our results still showed a notable functional homogeneity between the trophic groups in freshwater environments. Beta diversity was higher among freshwater samples, suggesting a greater level of heterogeneity within this group of samples concerning the composition and abundance of OTUs.Ciliophora was the most represented group in freshwater, while Diatomea dominated diversity in coastal lagoons.

Distinct community assembly processes and habitat specialization driving the biogeographic patterns of abundant and rare bacterioplankton in a brackish coastal lagoon

The ecological diversity patterns and community assembly processes along spatio-temporal scales are least studied in the bacterioplankton sub-communities of brackish coastal lagoons. We examined the biogeographic patterns and relative influences of different assembly processes in structuring the abundant and rare bacterioplankton sub-communities of Chilika, the largest brackish water coastal lagoon of India. Rare taxa demonstrated significantly higher α- and β-diversity and biogeochemical functions than abundant taxa in the high-throughput 16S rRNA gene sequence dataset. The majority of the abundant taxa (91.4 %) were habitat generalists with a wider niche breadth (niche breadth index, B = 11.5), whereas most of the rare taxa (95.2 %) were habitat specialists with a narrow niche breadth (B = 8.9). Abundant taxa exhibited a stronger distance-decay relationship and higher spatial turnover rate than rare taxa. β-diversity partitioning revealed that the contribution of species turnover (72.2–97.8 %) was greater than nestedness (2.2–27.8 %) in causing the spatial variation in both abundant and rare taxa. Null model analyses revealed that the distribution of abundant taxa was mostly structured by stochastic processes (62.8 %), whereas deterministic processes (54.1 %) played a greater role in the rare taxa. However, the balance of these two processes varied across spatio-temporal scales in the lagoon. Salinity was the key deterministic factor controlling the variation of both abundant and rare taxa. Potential interaction networks showed a higher influence of negative interactions, indicating that species exclusion and top-down processes played a greater role in the community assembly. Notably, abundant taxa emerged as keystone taxa across spatio-temporal scales, suggesting their greater influences on other bacterial co-occurrences and network stability. Overall, this study provided detailed mechanistic insights into biogeographic patterns and underlying community assembly processes of the abundant and rare bacterioplankton over spatio-temporal scales in a brackish lagoon.

Flooding of a carbonate platform: The Sian Kaʼan Wetlands, Yucatán, Mexico—A model for the formation and evolution of palustrine carbonate factories around the modern Caribbean Sea and in the depositional record

AbstractThe dynamic inter‐relationships between marine and freshwater carbonate depositional environments are illustrated in the Sian Ka'an Wetlands, a 5 280 km2 complex of groundwater‐fed freshwater marshes, lakes and brackish coastal lagoons in the South‐East Yucatán Peninsula (Mexico). The Yucatán Platform was subaerially emergent and extensively karstified during the last glacial maximum at 18, 000 yr bp. The Late Holocene transgression has caused progressive reflooding of the continental margin, backstepping of the MesoAmerican Reef and encroachment of coastal environments into the platform interior as rising groundwaters flood an interconnected cave and sinkhole system and feed seasonal marshes above. The Sian Ka'an Wetlands form a vast palustrine carbonate factory which is directly juxtaposed and dynamically linked with the marine carbonate factory to seaward. Continuing sea‐level rise has caused synchronous landward migration of marginal marine and freshwater environments as beach barriers were breached and palustrine sloughs flooded to form marginal marine seagrass lagoons. The Rio Hondo Fault conditions fluid inflow while the sub‐environments of the Sian Ka'an Wetlands reflect tectonic controls on microtopography and hydroperiod. Modern analogues for the Sian Ka'an Wetlands include the Florida Everglades, formed during transgression of the Florida Platform, and relict marsh environments preserved on leeward shores of Andros, Abaco and other Bahama islands. A wide range of ancient examples deposited in coastal and continental interior settings similarly reflect seasonal aquifer rise in response to marine transgression and/or onlap of late‐stage basin fill onto a karstified pediment. Freshwater palustrine carbonate factories on carbonate platforms are transient deposystems, controlled by subtle water depth, climate, vegetation and hydrological factors while being critically sensitive to sea‐level changes and tectonics. The preservation potential of palustrine carbonates may be relatively low in coastal settings due to erosion or shallow marine overprinting, while greater further inland where marine flooding is rarer and in tectonically subsident continental interior basins where accommodation space is continuously created.

Unravelling Stock Spatial Structure of Silverside Odontesthes argentinensis (Valenciennes, 1835) from the North Argentinian Coast by Otoliths Shape Analysis

The marine silverside (Odontesthes argentinensis) is an euryhaline species, distributed along the southwest coast of the Atlantic Ocean, present in estuaries, brackish coastal lagoons and shallow marine waters. It is a significant economic resource for local fisheries in southern Brazil, Uruguay and Argentina. The aim of this work was to contribute to knowledge on the stock spatial structure of the silverside, using otolith shape analysis, based on samples from nine locations in the Argentinian Sea, covering a large distribution range of the species. A combination of elliptic Fourier descriptors, Wavelet coefficients and otolith Shape indices were explored by multivariate statistical methods. The application of wavelet and combined wavelet, Fourier and Shape Indices were the most effective variables to discriminate between sampling sites (7.42 total error). PERMANOVA analysis of otolith shape revealed multivariate significant differences between north versus south locations (p < 0.0001). The results obtained show that the spatial structure of O. argentinensis presents a North–South gradient with marked differences between the extreme localities of the north (Mar del Plata, Quequén) with more elliptical shapes than those in the south (San Blas, San Antonio Este) and an isolated group conformed by Puerto Lobos.

Morphometric study of Balkan Terrapin, Mauremys rivulata (Testudines: Geoemydidae) in Çanakkale (Turkey)

Mauremys rivulata (Family Geoemydidae) is a medium-sized freshwater turtle inhabiting various natural and manmade habitats, including rivers, seasonal ponds, lakes, brackish coastal lagoons, irrigation canals, and reservoirs. In this study, the morphology of four different Mauremys rivulata populations in Çanakkale was evaluated between populations and sexes. The straight carapace length (SCL), carapace width (CW), plastron length (PL), plastron width (PW), body weight (W) measurements were obtained from a total of 114 adult specimens from four populations. The body sizes were examined comparatively in four Mauremys rivulata populations from Kavak Delta located in the Thrace region, City Center located in Anatolia, and two islands (Gökçeada and Bozcaada) which are the districts of Çanakkale. Significant differences were found between males and females in all populations, with females being larger than males. When the four populations were compared, it was determined that Gökçeada population is the largest specimens (Female SCL 197,23±7,545; Male SCL 187,47±13,757) and City Center population is the smallest specimens (Female SCL 152,02±23,391; Male SCL 129,67±20,466).

Presence of the Pink shrimp Farfantepenaeus brasiliensis (Latreille, 1817) in the coastal lagoons of Uruguay (Crustacea: Decapoda: Penaeoidea)

Farfantepenaeus brasiliensis (Latreille, 1817) and Farfantepenaeus paulensis (Pérez Farfante, 1967), commonly known as pink shrimps, are two commercially important penaeid species caught by artisanal and industrial fisheries in the Southwestern Atlantic Ocean. The currently known southern distribution for F. brasiliensis extends to Rio Grande do Sul (Brazil), while F. paulensis reaches the coastal waters of Buenos Aires (Argentina), although Uruguay represents the southern limit of commercial captures for the latter. In the shrimp season of 2019 (February-May) the presence of F. brasiliensis was recorded together with F. paulensis in the brackish coastal lagoons of Uruguay (34º30’ to 34º50’S). A total of 143 specimens of F. brasiliensis and 152 of F. paulensis were analyzed evaluating morphological, morphometric and genetic differences. The presence of both species was validated based on morphological differences and sequencing the Cytochrome Oxidase I (COI) mitochondrial gene. Significant morphometric differences were found between both species, particularly, the larger rostral length in relation to the carapace and cephalothorax length in F. paulensis compared to F. brasiliensis. To our knowledge, this is the first confirmed record and commercial catch of F. brasiliensis in Uruguayan waters. This southwards expansion could be explained by extending climatic variability events associated with prolonged periods of positive sea surface temperature anomalies in the region. Given the potential commercial relevance of the species, a better understanding of the southward expansion of F. brasiliensis into Uruguayan waters would be helpful in developing efficient management and conservation strategies under a scenario of increasing water temperatures.

Responses of phytoplankton community structure and association to variability in environmental drivers in a tropical coastal lagoon

Spatial and seasonal heterogeneity in phytoplankton communities are governed by many biotic and abiotic drivers. However, the identification of long-term spatial and temporal trends in abiotic drivers, and their interdependencies with the phytoplankton communities' structure is understudied in tropical brackish coastal lagoons. We examined phytoplankton communities' spatiotemporal dynamics from a 5-year dataset (n = 780) collected from 13 sampling stations in Chilika Lagoon, India, where the salinity gradient defined the spatial patterns in environmental variables. Generalized additive models showed a declining trend in phytoplankton biomass, pH, and dissolved PO4 in the lagoon. Hierarchical modelling of species communities revealed that salinity (44.48 ± 28.19%), water temperature (4.37 ± 5.65%), and season (4.27 ± 0.96%) accounted for maximum variation in the phytoplankton composition. Bacillariophyta (Indicator Value (IV): 0.74) and Dinophyta (IV: 0.72) emerged as top indicators for polyhaline regime whereas, Cyanophyta (IV: 0.81), Euglenophyta (IV: 0.79), and Chlorophyta (IV: 0.75) were strong indicators for oligohaline regime. The responses of Dinophyta and Chrysophyta to environmental drivers were much more complex as random effects accounted for ~70–75% variation in their abundances. Prorocentrum minimum (IV: 0.52), Gonyaulax sp. (IV: 0.52), and Alexandrium sp. (IV: 0.51) were potential indicators of P-limitation. Diploneis weissflogii (IV: 0.43), a marine diatom, emerged as a potential indicator of N-limitation. Hierarchical modelling revealed the positive association between Cyanophyta, Chlorophyta, and Euglenophyta whereas, Dinophyta and Chrysophyta showed a negative association with Cyanophyta, Chlorophyta, and Euglenophyta. Landsat 8-Operational Land Imager satellite models predicted the highest and lowest Cyanophyta abundances in northern and southern sectors, respectively, which were in accordance with the near-coincident field-based measurements from the lagoon. This study highlighted the dynamics of phytoplankton communities and their relationships with environmental drivers by separating the signals of habitat filtering and biotic interactions in a monsoon-regulated tropical coastal lagoon.

Spatiotemporal patterns and impact of a cyclone on the zooplankton community structure in a brackish coastal lagoon

Zooplankton communities in response to hydrological (salinity, turbidity, water temperature, nitrate, phosphate, silicate) and biological (phytoplankton density) variables were studied in the Asia’s largest brackish water lagoon, Chilika (India). Water samples were collected from 13 stations on a monthly frequency between July 2014–June 2015. A total of 141 species of holoplankton including Ciliophora, Foraminifera, Rotifera, Rhizopoda, Gastropoda, Cladocera, Copepoda, Ostracoda, Malacostraca, Chaetognatha, Chordata, Nematoda, and 18 types of planktonic larvae were identified. Copepods were the most dominant and diverse zooplankton in terms of their species richness, numerical abundance, and widespread distribution in the lagoon. The major holoplanktonic taxa were Acartia sp., Acrocalanus gibber, Acrocalanus gracilis, Acrocalanus longicornis, Euterpina acutifrons, Lecane sp., Oithona sp., Pseudodiaptomus serricaudatus, and Tintinnopsis tubulosa. The dominant planktonic larvae were bivalve veliger, copepod nauplii, cyphonautes larvae, gastropod veliger, and protozoea of lucifer. Canonical correspondence analysis showed that distribution of zooplankton assemblages was influenced by salinity, turbidity, and phytoplankton density. Indicator analysis demarcated 26 indicator zooplankton taxa. Of these, the most prominent indicator zooplankton such as Belzebub hanseni, Mesopodopsis orientalis, Chydorus sphaericus, and Corycaeus catus were characteristic to salinity gradient in southern sector, sediment resuspension in central sector, eutrophic conditions in northern sector, and tide-induced intrusion of marine forms in outer channel, respectively. Hudhud, a category 4 cyclone resulted decline in the abundances of zooplankton population. Copepod nauplii and copepodites were dominant during post-Hudhud and their succession was linked to the increased phytoplankton density due to an upsurge in the nutrient level in the northern sector of the lagoon. The present study provided a comprehensive detail on the zooplankton composition and their environmental drivers including the impact of a tropical cyclone from a tropical coastal lagoon system.

A GIS-based assessment combined with local ecological knowledge to support the management of Juncus acutus L. spreading in the floodplain of a protected coastal lagoon

The floodplains of brackish coastal lagoons are subject to a highly dynamic hydrological regimen mainly due to their intermittent connection with the ocean. Coastal lagoons generally support fisheries, while livestock ranching and human settlements are found in the floodplain. Therefore, it is common practice to artificially open the sand barrier to avoid floods and manage fish stocks. Saltmarsh species are subject to grazing pressure and to changes in flooding and salinity regimens, affecting plants’ community structure. In the Laguna de Rocha Protected Landscape, a shallow brackish coastal lagoon located in Uruguay (South America), livestock ranchers complain about the spreading of the native cyperacea Juncus acutus L. The plant forms dense mats in the outermost zones of the floodplain, apparently displacing natural grasslands where the cattle graze. Also, stakeholders have encouraged the park authorities to artificially open the lagoon to obtain short-term benefits for fisheries and cattle raising. The study evaluated the increase in the surface area occupied by J. acutus and analyzed the possible causes of this increase as a basis for suggesting management actions. Historical and current aerial and satellite images, historical hydrological and climatic data and local ecological knowledge about the biology of the species and its spatial distribution over time were analyzed. The results indicate that J. acutus expanded in the floodplain of Laguna de Rocha, possibly starting ca. 2000, to cover less than 100 ha of the study area at low and high density. The results confirm most of the information obtained from the local stakeholders, whose local ecological knowledge was highly useful in understanding some local processes and providing information regarding periods for which data were not available. The expansion of J. acutus can be explained by a multiplicity of causes that acted synergistically to favor the species through a series of changes in the management of the sand barrier, livestock management and climate variability. However, a quantification of the economic effects of J. acutus on cattle feeding and fisheries is needed. Possible actions to control J. acutus expansion involve management of the grazing pressure using sheep, burning with fire, mechanical removal and avoiding artificial opening of the lagoon to allow larger and longer floods to occur and permit recovery of the previous, more natural hydrological regime. Our results suggest that it is important to be cautious before taking management actions to avoid costly solutions that are only short-term palliatives that could trigger other unforeseen environmental impacts.

Salinization Increase due to Climate Change Will Have Substantial Negative Effects on Inland Waters: A Call for Multifaceted Research at the Local and Global Scale

Salinization Increase due to Climate Change Will Have Substantial Negative Effects on Inland Waters: A Call for Multifaceted Research at the Local and Global Scale

The resilience of macrozoobenthos of boreal coastal lagoons to non-indigenous species invasion: A case study of Taman Bay (the Sea of Azov)

The aim of the present study is to reveal the consequences of the blood ark (Anadara kagoshimensis) invasion of Taman Bay (the Sea of Azov), one of the biggest boreal brackish coastal lagoon. Anadara kagoshimensis was found there for the first time in 2003. During our work from 2003 to 2013, the blood arks were found at eleven of 83 stations in the bay. The invader was observed at 0.5–6 m depths in two habitat types: unvegetated muddy bottom and sparse Phragmithes sp. vegetation. The occurrence of both A. kagoshimensis and indigenous dominant species in the same localities varied from year to year. The ES100 index and taxonomic composition did not significantly differ between stations with and without the arks. The variation in the macrozoobenthos species abundance did not depend on whether the alien or indigenous species were dominant. The arks have integrated into the local communities with dominating native macrozoobenthos organisms. This scenario contrasts with the blood arks’ invasion into the Adriatic, Black and Azov Seas, and the adjacent Kerch Strait. There, distinct ark communities have replaced disturbed communities with native dominant species. The main factors that determine the resilience of macrozoobenthos in Taman Bay are: no pressure from the Rapa whelk (Rapana venosa); no persistent disturbances and the eurybiontic type fauna of the bay.

Biochemical and genotoxic biomarkers in Atherina boyeri to evaluate the status of aquatic ecosystems

Transitional water ecosystems, like brackish coastal lagoons, provide important services but are subjected to several anthropogenic impacts that can initially lead to biodiversity modifications and then to critical alterations of ecosystem processes. Assessment and monitoring of the health status of these ecosystems is extremely important. This study reports the case study of “Capo Peloro” lakes (southern Italy), where ecotoxicological biomarkers in the key fish species Atherina boyeri have been used to reveal potential contamination in a transitional water ecosystem. The goal was to detect changes that occurred after the summer season, when the surrounding human population significantly increases, with the consequent enhancement of anthropic pressures. Lake Trasimeno, a reference protected site, was also selected. This study is the follow-up of a previous one carried out in the same environment reporting biomarkers employed on the copepod species Paracartia latisetosa, on which Atherina boyeri feeds. The main aim of the present study was to test the responses given by the same type of contamination in a planktivorous fish species, which occupies a higher trophic level. Several biochemical and genotoxic biomarkers were evaluated: Acetylcholinesterase (AChE), Benzo(a)pyrene-monooxygenase (BPMO), Polycyclic Aromatic Hydrocarbons (PAH) metabolites in bile, Erythrocytic Nuclear Abnormalities (ENA) assay. This study confirms the contamination already shown in P. latisetosa from pesticides and carbamates, and/or polycyclic and polyhalogenated aromatic hydrocarbons, heavy metals, surfactants in both “Capo Peloro” lakes. A higher concentration of contaminants was demonstrated in early autumn with respect to the summer season, due to enhanced anthropogenic activities around and on the lakes. This study highlights that, although “Capo Peloro” lakes and Lake Trasimeno are protected areas, they are affected by environmental degradation. This study also confirms the benefits gained with a biomarker approach in monitoring transitional water ecosystems.

Returning of Hippocampus hippocampus (Linnaeus, 1758) (Syngnathidae) in the Faro Lake – oriented Natural Reserve of Capo Peloro, Italy

This study reports the returning of the seahorse in the Faro Lake and the most recent finding in a brackish coastal Mediterranean lagoon. After about 50 years from the first documented occurrence of Hippocampus hippocampus (Linnaeus, 1758) within the “Capo Peloro Lagoons”, North East Sicily, two adult specimens were observed alive in 2015. During that time, until the present rediscovery, the species was not recorded in biological studies and censuses for the area. This paper increases the knowledge about both the threatened seahorse species and the Natural Oriented Reserve of Capo Peloro.

Spatio-temporal influence of physicochemical parameters on phytoplankton assemblage in coastal brackish lagoon: Gomishan Lagoon, Caspian Sea, Iran

Jabbari M, Salahi M, Ghorbani R. 2018. Spatio-temporal influence of physicochemical parameters on phytoplankton assemblage in coastal brackish lagoon: Gomishan Lagoon, Caspian Sea, Iran. Biodiversitas 19: 2020-2027. The objective of this study was to determine the spatiotemporal distribution pattern of phytoplankton assemblage due to physico-chemical heterogeneity in coastal brackish lagoon of Gomishan. An inter-annual cycle of sampling period (April 2014-March 2015) and spatially stratified random sampling were established to examine 24 spatiotemporal scenarios. Water samples were preserved in 1 and 0.5 liter dark Polythene bottles from each station for assessing plankton community and chlorophyll a, respectively. The applied multivariate approach including hierarchical cluster analysis for (dis)similarity test of environmental factors, principle component analysis (PCA) and canonical correspondence analysis (CCA) was used to illustrate the pattern of phytoplankton variability in relation to environmental characteristics. The results showed that mean salinity, temperature, pH, total nitrogen, phosphorus, silica, turbidity, and electrical conductivity (EC) were 22.8±5.9 (ppt), 23.4° C, 8.18, 2.49 (mg.l-1), 0.258 (mg.l-1), 3.39 (mg.l-1), 42.12 (NTU), and 3.78 (dS/m3), respectively. Scenarios S5AT, S5W, S6W, S6AT were distinguished from other scenarios with more than 90% similarity, subsequently S1SU and S5SU with about 80% similarity. Inter-annual mean density of total phytoplankton (cell.l-1) was 2.45×106, whereas in northern sector it was constant with only a peak in June, but in southern sector it was more tolerant, so in April it tended to increase with a peak (7.2×106) in July which was the maximum density over the year. The phytoplankton assemblage of the lagoon comprised 47 species from 5 different classes including Bacillariophyta, Pyrrophyta, Chlorophyta, Cyanophyta, and Euglenophyta.

A conceptual model for groundwater discharge to a coastal brackish lagoon based on seepage measurements (Ringkøbing Fjord, Denmark)

AbstractGroundwater discharge to a brackish lagoon (Ringkøbing Fjord) was quantified with seepage meters along four transects perpendicular to the shore during four seasons in 1 year. The objectives were to develop a conceptual model of the spatiotemporal variability of seepage and how landscape characteristics and saltwater intrusion affect seepage fluxes. The electrical conductivity of the groundwater was measured in vertical sediment profiles up to 3 m below the lagoon bed to assess the effects of the freshwater–saltwater interface location on flux distribution. The main differences compared with existing theoretical models are a lower discharge near the shore line (0–5 m) and two discharge peaks more offshore (15–20 and >25 m), which allowed the development of a conceptual model that is different from the classical concepts introduced for marine or lake environments and which can be representative of other similar areas. These differences are explained by the vegetation and organic material deposition in the near‐shore environment reducing discharge, the presence of the saline wedge leading to upward flow, and the increase of recirculation of brackish water due to wave pumping in areas offshore most exposed to the wind. The seasonal variability in discharge is smaller than the spatial variability between and within transects along the shoreline. Based on the conceptual model, fresh water discharge in a 20‐m‐wide fringe was calculated to be between 66 and 388 L·day−1·m−1 shore line, corresponding to a difference of a factor of six due to the variations in coast morphology and local characteristics of the area. The seasonal changes were responsible for changes of only 8% to 75% depending on the location.

Efficacy of Coagulants and Ballast Compounds in Removal of Cyanobacteria (Microcystis) from Water of the Tropical Lagoon Jacarepaguá (Rio de Janeiro, Brazil)

Eutrophication is considered the most important water quality problem in freshwaters and coastal waters worldwide promoting frequent occurrence of blooms of potentially toxic cyanobacteria. Removal of cyanobacteria from the water column using a combination of coagulant and ballast is a promising technique for mitigation and an alternative to the use of algaecides. In laboratory, we tested experimentally the efficiency of two coagulants, polyaluminium chloride (PAC) and chitosan (made of shrimp shells), alone and combined with two ballasts: red soil (RS) and the own lagoon sediment, to remove natural populations of cyanobacteria, from an urban brackish coastal lagoon. PAC was a very effective coagulant when applied at low doses (≤8 mg Al L−1) and settled the cyanobacteria, while at high doses (≥16 mg Al L−1) large flocks aggregated in the top of test tubes. In contrast, chitosan was not able to form flocks, even in high doses (>16 mg L−1) and did not efficiently settle down cyanobacteria when combined with ballast. The RS itself removed 33–47 % of the cyanobacteria. This removal was strongly enhanced when combined with PAC in a dose-dependent matter; 8 mg Al L−1 was considered the best dose to be applied. The lagoon sediment alone did not promote any settling of cyanobacteria but removal was high when combined with PAC. Combined coagulant and ballast seems a very efficient, cheap, fast and safe curative measure to lessen the harmful cyanobacteria bloom nuisance in periods when particularly needed, such as around the 2016 Olympics in Jacarepagua Lagoon.