Editorial

3 pages, 176 KiB

Open AccessEditorial

Advances in Mountain and Mediterranean Wetlands Conservation

by Francisco Guerrero

Water 2021, 13(14), 1953; https://doi.org/10.3390/w13141953 - 16 Jul 2021

Cited by 1 | Viewed by 1681

It is well known that wetlands are one of the most threatened ecosystems in the world, being also considered as environments with great natural, economic, and socio-cultural values [...] Full article

(This article belongs to the Special Issue Advances in Mountain and Mediterranean Wetlands Conservation)

Research

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15 pages, 3112 KiB

Open AccessFeature PaperArticle

Zooplankton Community Dynamics in Temporary Mediterranean Wetlands: Which Drivers Are Controlling the Seasonal Species Replacement?

by Juan Diego Gilbert, Inmaculada de Vicente, Fernando Ortega and Francisco Guerrero

Water 2021, 13(11), 1447; https://doi.org/10.3390/w13111447 - 21 May 2021

Cited by 8 | Viewed by 1853

Abstract

Temporary Mediterranean wetlands are characterized by both intra and interannual variations in their environmental conditions. These inherent fluctuations in limnological features affect the seasonal variation in the structure and dynamics of the aquatic communities. In this study, we hypothesized that zooplankton community is [...] Read more.

Temporary Mediterranean wetlands are characterized by both intra and interannual variations in their environmental conditions. These inherent fluctuations in limnological features affect the seasonal variation in the structure and dynamics of the aquatic communities. In this study, we hypothesized that zooplankton community is coupled to seasonal changes of the environmental variables along the hydroperiod. To get this purpose, the study was focused in monitoring, by collecting monthly samples during an annual period, seven temporary Mediterranean ponds located in the south-eastern region of the Iberian Peninsula (Alto Guadalquivir region, Andalusia). The relationships between zooplankton community and the different limnological variables were analyzed based on two approaches: a Spearman correlation analysis and a correspondence canonical analysis (CCA). The results have shown that chlorophyll-a concentration, Secchi depth, total nitrogen concentration, wetland area and depth were the variables with a greater influence on the zooplankton community, explaining the zooplankton species replacement. Moreover, optima and tolerance of the zooplankton species were obtained from the position of species within CCA diagram, allowing the separation of different groups of zooplankton along the hydroperiod. We finally highlight that the monitoring of zooplankton community and environmental conditions are necessary to evaluate how theses singular and endangered aquatic ecosystems will be affected by anthropogenic activities in the future. Full article

(This article belongs to the Special Issue Advances in Mountain and Mediterranean Wetlands Conservation)

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17 pages, 2938 KiB

Open AccessArticle

Promotion of the Development of Sentinel Species in the Water Column: Example Using Body Size and Fecundity of the Egg-Bearing Calanoid Copepod Eurytemora affinis

by Sami Souissi and Anissa Souissi

Water 2021, 13(11), 1442; https://doi.org/10.3390/w13111442 - 21 May 2021

Cited by 6 | Viewed by 2144

Abstract

The development of sentinel species in aquatic ecosystems is mostly based on benthic organisms; however, organisms living in water column such as zooplankton have received less attention, except for some cladocerans. In this paper, a new ecological indicator based on simple measurements of [...] Read more.

The development of sentinel species in aquatic ecosystems is mostly based on benthic organisms; however, organisms living in water column such as zooplankton have received less attention, except for some cladocerans. In this paper, a new ecological indicator based on simple measurements of the size and fecundity of egg-bearing calanoid copepods is developed. The well-studied estuarine copepod Eurytemora affinis is used to illustrate this new framework. A large database obtained from laboratory experiments developed under different conditions is used to define a reference regression line between clutch size (CS) and prosome length (PL). The same database allowed one to confirm that the coefficient of variation (CV) of CS is an adequate estimator of the accumulated stress at population level. The CV of PL shows very little variability in all experimental and field conditions. The values of CS and PL obtained from the Seine, Loire, Gironde, Scheldt and Elbe estuaries in Europe are compared to the reference regression line. A quality index (QI) is calculated as a percentage of difference between the observed and the predicted CS. The QI classified 19 samples collected in the Seine estuary between 2004 and 2010 into four classes according to the physiological condition of the copepod female. A single sampling from June 2004 (5.26%) showed a very good condition, whereas 57.9% of the sampling dates confirmed good conditions. On the other hand, four sampling dates were associated to very bad conditions and three sampling dates indicated bad conditions. Seven additional samples obtained from other European estuaries between 2006 and 2009 were also used. Females showing poor conditions were observed in the early spring of 2005 and 2008 as well as during the month of November. These years were characterized by very strong climatic anomalies with a very cold late winter in 2005 and a warm winter in 2008. Therefore, it seems that the QI perfectly reflected the strong stress caused by the sudden change in hydro-climatic conditions that have certainly affected the physiology of copepod females and probably the availability of food. The new indicator is very simple to calculate and can be generalised to several aquatic ecosystems (fresh water and brackish water) by targeting the dominating egg-bearing calanoid copepods. As in the case of E. affinis, the development of sentinel species based on copepods or cladocerans can enrich ecological and ecotoxicological studies given their capacity to integrate the variability of their habitats’ quality at the individual and population levels. Full article

(This article belongs to the Special Issue Advances in Mountain and Mediterranean Wetlands Conservation)

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14 pages, 13235 KiB

Open AccessFeature PaperArticle

Epiphytic Diatom-Based Biomonitoring in Mediterranean Ponds: Traditional Microscopy versus Metabarcoding Approaches

by María Borrego-Ramos, Eloy Bécares, Pedro García, Alejandro Nistal and Saúl Blanco

Water 2021, 13(10), 1351; https://doi.org/10.3390/w13101351 - 13 May 2021

Cited by 13 | Viewed by 2744

Abstract

Benthic diatoms have traditionally been used as bioindicators of aquatic ecosystems. Because diatom-based monitoring of water quality is required by European legislation, molecular-based methods had emerged as useful alternatives to classical methods based on morphological identification using light microscopy. The aim of this [...] Read more.

Benthic diatoms have traditionally been used as bioindicators of aquatic ecosystems. Because diatom-based monitoring of water quality is required by European legislation, molecular-based methods had emerged as useful alternatives to classical methods based on morphological identification using light microscopy. The aim of this study was to test the reliability of DNA metabarcoding combined with High-Throughput Sequencing (HTS) techniques in the bioassessment of the trophic status of 22 Mediterranean shallow ponds in NW Spain. For each pond, the Trophic Diatom Index (TDI) was calculated from inventories obtained by identification using light microscopy (LM) followed by high-throughput sequencing (HTS) at the molecular level. Ponds were subsequently classified into five water quality classes. The results showed a good correspondence between both methods, especially after applying a correction factor that depended on the biovolume of the cells. This correspondence led to the assignment to the same quality class in 59% of the ponds. The determination and quantification of valves or DNA sequences was one of the main pitfalls, which mainly included those related to the variability in the relative abundances of some species. Accordingly, ponds with similar relative abundances for the dominant species were assigned to the same quality class. Moreover, other difficulties leading the discrepancies were the misidentification of some species due to the presence of semi-cryptic taxa, the incompleteness of the reference database and the bioinformatic protocol. Thus, the validation of DNA-based methods for the identification of freshwater diatoms represents an important goal, as an alternative to using traditional methods in Mediterranean shallow ponds. Full article

(This article belongs to the Special Issue Advances in Mountain and Mediterranean Wetlands Conservation)

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16 pages, 1739 KiB

Open AccessFeature PaperArticle

On the Occurrence of Metadiaptomus chevreuxi (Calanoida, Diaptomidae, Paradiaptominae) in the Iberian Peninsula, With Notes on the Ecology and Distribution of its European Populations

by Federico Marrone, Fernando Ortega, Francesc Mesquita-Joanes and Francisco Guerrero

Water 2020, 12(7), 1989; https://doi.org/10.3390/w12071989 - 14 Jul 2020

Cited by 11 | Viewed by 2380

Abstract

Temporary ponds are one of the most peculiar ecosystems in the world, being characterized by an extraordinarily rich crustacean fauna, with a high degree of endemism. Among them, diaptomid copepods are among the most biogeographically interesting taxa. However, the present knowledge on diaptomid [...] Read more.

Temporary ponds are one of the most peculiar ecosystems in the world, being characterized by an extraordinarily rich crustacean fauna, with a high degree of endemism. Among them, diaptomid copepods are among the most biogeographically interesting taxa. However, the present knowledge on diaptomid distribution is still far from being exhaustive, even in the relatively well-studied western European countries. In this study, we report the first record of the diaptomid calanoid copepod Metadiaptomus chevreuxi for the Iberian Peninsula, where it was collected in five temporary ponds in Andalusia (Spain). The characteristics of the new sites are described, the literature dealing with the European localities of the species is reviewed, and a molecular phylogenetic tree has been built, based on new and previously available mitochondrial DNA sequences, thus expanding the knowledge on the ecology and phylogeography of this rare species. The species mainly occupies small isolated temporary ponds in (semi-)arid regions, suggesting adaptations to unpredictable aquatic habitats. The existence of two molecular clades separating the Iberian from the Sicilian and Tunisian populations supports the existence of a longitudinal long-term disjunction, whereas the north-south flow is probably facilitated by migrating birds. Further research on the biota of the small water bodies of the western Mediterranean area may help to expand our knowledge on rare aquatic species, such as M. chevreuxi, and to better interpret their natural history. Full article

(This article belongs to the Special Issue Advances in Mountain and Mediterranean Wetlands Conservation)

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13 pages, 2513 KiB

Open AccessArticle

What Triggers the Annual Cycle of Cyanobacterium Oscillatoria sp. in an Extreme Environmental Sulfide-Rich Spa?

by Andreas Reul, Elena Martín-Clemente, Ignacio J. Melero-Jiménez, Elena Bañares-España, Antonio Flores-Moya and María J. García-Sánchez

Water 2020, 12(3), 883; https://doi.org/10.3390/w12030883 - 21 Mar 2020

Cited by 5 | Viewed by 3409

Abstract

A seasonal cycle of sulfide, nitrate, phosphate, ammonium, chlorophyll a (Chl a) and Oscillatoria sp. abundance (<100 μm), as well as the relative contribution of taxonomic phytoplanktonic groups (cyanobacteria, green algae, cryptomonads, diatoms and dinoflagellates) to total Chl a were measured by [...] Read more.

A seasonal cycle of sulfide, nitrate, phosphate, ammonium, chlorophyll a (Chl a) and Oscillatoria sp. abundance (<100 μm), as well as the relative contribution of taxonomic phytoplanktonic groups (cyanobacteria, green algae, cryptomonads, diatoms and dinoflagellates) to total Chl a were measured by fluorometric measurements at La Hedionda sulfide-rich spa (southern Spain). Fluorometry determined that cyanobacteria Chl a concentration correlated positively with the abundance of Oscillatoria sp. Aggregates at 45–100 μm equivalent spherical diameter (ESD) and was used as an indicator of Oscillatoria sp. Abundance, including for aggregates <45 and >100μm (ESD). In addition, air temperature, radiation and precipitation were downloaded from meteorological databases. In agreement with the meteorological annual cycle observed in air temperature, radiation and precipitation, sulfide concentration at La Hedionda Spa shows an annual cycle with concentrations around 40 μM in winter and up to 200 μM in the dry summer period. Phytoplankton composition was dominated by cyanobacteria (mainly Oscillatoria sp.), but other groups were also represented (green algae, cryptomonads, diatoms and dinoflagellates), although they remained constant throughout the year (median Chl a < 0.2 μg L⁻¹). Cyanobacteria, in contrast, showed an annual cycle with a significantly higher median in summer (Chl a = 1.6 μg L⁻¹) than in winter (Chl a = 0.4 μg L⁻¹). No linear relationship between nutrients and cyanobacteria concentration was observed, but an optimum curve of cyanobacteria concentration to sulfide concentration was fitted through a general additive model (GAM). The four-fold increase of cyanobacteria concentration under exposition of an elevated sulfide concentration can be due to higher growth rates at elevated sulfide concentrations reported for an Oscillatoria sp. strain isolated during the same annual cycle at La Hedionda and we suggest that the selective agent, sulfide, positively triggers Oscillatoria sp. proliferation in summer. According to our findings, the Oscillatoria sp. population of La Hedionda not only is sulfide-resistant, but requires sulfide in its optimal niche. Full article

(This article belongs to the Special Issue Advances in Mountain and Mediterranean Wetlands Conservation)

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14 pages, 1424 KiB

Open AccessArticle

Assessment of Biological and Sanitary Condition of Alien Fish from a High-Mountain Lake (Cottian Alps)

by Paolo Pastorino, Marino Prearo, Marco Bertoli, Vasco Menconi, Giuseppe Esposito, Marzia Righetti, Davide Mugetti, Sabina Pederiva, Maria Cesarina Abete and Elisabetta Pizzul

Water 2020, 12(2), 559; https://doi.org/10.3390/w12020559 - 18 Feb 2020

Cited by 13 | Viewed by 3187

Abstract

This study aimed to assess the biological and sanitary conditions of alien fish in a high-mountain lake (Balma Lake) located in the Cottian Alps. A single fish sampling session (August 2018) using gillnets collected 90 specimens of brook trout (Salvelinus fontinalis). [...] Read more.

This study aimed to assess the biological and sanitary conditions of alien fish in a high-mountain lake (Balma Lake) located in the Cottian Alps. A single fish sampling session (August 2018) using gillnets collected 90 specimens of brook trout (Salvelinus fontinalis). Sex and age were determined (59 females and 31 males, age class 0+ to 4+). Regression analysis showed no difference in total weight and total length between males and females (ANCOVA: F = 0.453; p = 0.954). The mean condition factor (K_mean) decreased with increasing age for males and females. Terrestrial insects were the main prey found in the fish stomachs. The parasitological exam was negative, and the bacteriological exam was positive for Carnobacterium maltaromaticum and C. divergens in 33% of specimens. The total mercury, cadmium, and lead concentration in muscle tissue was within the maximum limit established by the European Commission for human consumption. The brook trout population was found to be well structured; these findings may help local administrations in the implementation of eradication measures. Full article

(This article belongs to the Special Issue Advances in Mountain and Mediterranean Wetlands Conservation)

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Review

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20 pages, 1042 KiB

Open AccessFeature PaperReview

Biogeochemistry of Mediterranean Wetlands: A Review about the Effects of Water-Level Fluctuations on Phosphorus Cycling and Greenhouse Gas Emissions

by Inmaculada de Vicente

Water 2021, 13(11), 1510; https://doi.org/10.3390/w13111510 - 27 May 2021

Cited by 15 | Viewed by 4031

Abstract

Although Mediterranean wetlands are characterized by extreme natural water level fluctuations in response to irregular precipitation patterns, global climate change is expected to amplify this pattern by shortening precipitation seasons and increasing the incidence of summer droughts in this area. As a consequence, [...] Read more.

Although Mediterranean wetlands are characterized by extreme natural water level fluctuations in response to irregular precipitation patterns, global climate change is expected to amplify this pattern by shortening precipitation seasons and increasing the incidence of summer droughts in this area. As a consequence, a part of the lake sediment will be exposed to air-drying in dry years when the water table becomes low. This periodic sediment exposure to dry/wet cycles will likely affect biogeochemical processes. Unexpectedly, to date, few studies are focused on assessing the effects of water level fluctuations on the biogeochemistry of these ecosystems. In this review, we investigate the potential impacts of water level fluctuations on phosphorus dynamics and on greenhouse gases emissions in Mediterranean wetlands. Major drivers of global change, and specially water level fluctuations, will lead to the degradation of water quality in Mediterranean wetlands by increasing the availability of phosphorus concentration in the water column upon rewetting of dry sediment. CO₂ fluxes are likely to be enhanced during desiccation, while inundation is likely to decrease cumulative CO₂ emissions, as well as N₂O emissions, although increasing CH₄ emissions. However, there exists a complete gap of knowledge about the net effect of water level fluctuations induced by global change on greenhouse gases emission. Accordingly, further research is needed to assess whether the periodic exposure to dry–wet cycles, considering the extent and frequency of the cycles, will amplify the role of these especial ecosystems as a source of these gases and thereby act as a feedback mechanism for global warming. To conclude, it is pertinent to consider that a better understanding about the effect of water level fluctuations on the biogeochemistry of Mediterranean wetlands will help to predict how other freshwater ecosystems will respond. Full article

(This article belongs to the Special Issue Advances in Mountain and Mediterranean Wetlands Conservation)

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