Mediterranean springs: Keystone ecosystems and biodiversity refugia threatened by global change

Mediterranean spring ecosystems are unique habitats at the interface between surface water and groundwater. These ecosystems support a remarkable array of biodiversity and provide important ecological functions and ecosystem services. Spring ecosystems are influenced by abiotic, biotic, and anthropogenic factors such as the lithology of their draining aquifers, their climate, and the land use of their recharge area, all of which affect the water chemistry of the aquifer and the spring discharges. One of the most relevant characteristics of spring ecosystems is the temporal stability of environmental conditions, including physicochemical features of the spring water, across seasons and years. This stability allows a wide range of species to benefit from these ecosystems (particularly during dry periods), fostering an unusually high number of endemic species. However, global change poses important threats to these freshwater ecosystems. Changes in temperature, evapotranspiration, and precipitation patterns can alter the water balance and chemistry of spring water. Eutrophication due to agricultural practices and emergent pollutants, such as pharmaceuticals, personal care products, and pesticides, is also a growing concern for the preservation of spring biodiversity. Here, we provide a synthesis of the main characteristics and functioning of Mediterranean spring ecosystems. We then describe their ecological value and biodiversity patterns and highlight the main risks these ecosystems face. Moreover, we identify existing knowledge gaps to guide future research in order to fully uncover the hidden biodiversity within these habitats and understand the main drivers that govern them. Finally, we provide a brief summary of recommended actions that should be taken to effectively manage and preserve Mediterranean spring ecosystems for future generations. Even though studies on Mediterranean spring ecosystems are still scarce, our review shows there are sufficient data to conclude that their future viability as functional ecosystems is under severe threat.Mediterranean spring ecosystems are unique habitats supporting a remarkable array of biodiversity and providing important ecological functions and ecosystem services. However, global change poses important threats to these freshwater ecosystems, such as changes in climate patterns and increasing human pressures like overexploitation and pollution. We provide a synthesis of the main characteristics and functioning of Mediterranean spring ecosystems and their threats due to global change.imag

Mediterranean springs: Keystone ecosystems and biodiversity refugia threatened by global change

Mediterranean spring ecosystems are unique habitats at the interface between surface water and groundwater. These ecosystems support a remarkable array of biodiversity and provide important ecological functions and ecosystem services. Spring ecosystems are influenced by abiotic, biotic, and anthropogenic factors such as the lithology of their draining aquifers, their climate, and the land use of their recharge area, all of which affect the water chemistry of the aquifer and the spring discharges. One of the most relevant characteristics of spring ecosystems is the temporal stability of environmental conditions, including physicochemical features of the spring water, across seasons and years. This stability allows a wide range of species to benefit from these ecosystems (particularly during dry periods), fostering an unusually high number of endemic species. However, global change poses important threats to these freshwater ecosystems. Changes in temperature, evapotranspiration, and precipitation patterns can alter the water balance and chemistry of spring water. Eutrophication due to agricultural practices and emergent pollutants, such as pharmaceuticals, personal care products, and pesticides, is also a growing concern for the preservation of spring biodiversity. Here, we provide a synthesis of the main characteristics and functioning of Mediterranean spring ecosystems. We then describe their ecological value and biodiversity patterns and highlight the main risks these ecosystems face. Moreover, we identify existing knowledge gaps to guide future research in order to fully uncover the hidden biodiversity within these habitats and understand the main drivers that govern them. Finally, we provide a brief summary of recommended actions that should be taken to effectively manage and preserve Mediterranean spring ecosystems for future generations. Even though studies on Mediterranean spring ecosystems are still scarce, our review shows there are sufficient data to conclude that their future viability as functional ecosystems is under severe threat.This review was written thanks to the funding provided by the CREAF's Severo Ochoa CEX2018-000828-S Synthesis actions program. This research was supported by the Catalan government project SGR2021-01333, the European Research Council project ERC-StG-2022-101076740 STOIKOS and the Spanish MCIN project KALORET (PID2021-128778OA-I00). M.F-M. was supported by a Ramón y Cajal fellowship (RYC2021-031511-I) funded by the Spanish Ministry of Science and Innovation, the NextGenerationEU program of the European Union, the Spanish plan of recovery, transformation and resilience, and the Spanish Research Agency. E.R. was supported by the Severo Ochoa Excellence Program (CEX2018-000828-S) of the Spanish Research Agency. J.M.Z-M. was supported by a postdoctoral grant funded by the Spanish Ministry of Science and Innovation and the European Union NextGeneration EU/PRTR (FJC2021-046923-I). We acknowledge the Institució Catalana d'Història Natural (ICHN) and the Secció de Ciències Biològiques de l'Institut d'Estudis Catalans (IEC) for additional funding for studying Mediterranean springs. We thank Jordi Gomis (www.meteomataro.com) for providing publicly available climate data for the region of study. We finally thank the Direcció de Cultura, Ajuntament de Mataró for providing the venue to hold the workshop that promoted this review. We also thank Zeynep Ersoy, Ricardo Figueroa, Verónica Ferreira, Roderick J. Fensham (The Fellowship of the Spring), Manuel Graça, Vincent H. Resh, Boudjéma Samraoui, Farrah Samraoui, and Nikos Skoulikidis for providing invaluable information regarding cultural activities and traditions related to springs.info:eu-repo/semantics/publishedVersio

Diversity and abundance of potentially toxic pseudo-nitzschia peragallo in Aveiro coastal lagoon, Portugal and description of a new variety, p-pungens var. aveirensis var. nov.

The syndrome Amnesic Shellfish Poisoning (ASP) results From ingesting sea food contaminated by a neurotoxin, domoic acid. Diatoms of the genera Pseudo-nitzschia and Nitzschia are responsible for the production of this toxin. A total of eleven species of Pseudo-nitzschia were identified during two plankton surveys at the entrance and in the southern channels of Ria de Aveiro, the largest lagoon on the west coast of Portugal. During the first survey, conducted from February to October 2000, the following species were identified: P. australis, P. cuspidata, P. delicatissima, P. dolorosa, P. fraudulenta, P. pseudodelicatissima, P. subpacifica and a new variety of P. pungens. The second survey took place from September 2003 to April 2004, except for a break between December 2003-January 2004, along with one complementary sample taken in October 2004; it revealed three additional species, P. americana, P. calliantha and P. multistriata. In contrast, P. cuspidata, P. dolorosa and P. subpacifica were not found during the second survey. Five species: P. subpacifica, P. americana, P. calliantha, P. multistriata and P. cuspidata were reported for the First time in Portuguese waters. Overall, P australis, P. pseudodelicatissima and a new variety of P. pungens were the most common species, the latter being present in all samples except October 2000. The highest concentrations of Pseudo-nitzschia cells registered were 90,000 cells L(-1) in August 2000 and 106,000 cells L-1 in March 2004, with P. australis accounting for 65-75% of the cells. Cell concentrations were highest near the entrance of the lagoon and decreased along with salinity in the channels. Cultures of P. australis, P. americana, P. fraudulenta, P. multistriata and a new variety of P. pungens were established and tested for the production of domoic acid, but the results were negative. Morphological differences were found between Our strains of P. pungens and two other previously described varieties of P. pungens regarding valve width, densities of striae, fibulae, poroids and band striae as well as differences in the morphology of the band striae. These differences were supported by phylogenetic analyses of ITS rDNA sequences, existence of a compensatory base change and mating studies indicate the presence of a separate taxon, which was described as a new variety, P. pungens var. aveirensis var. nov

Effects of bacillamide and newly synthesized derivatives on the growth of cyanobacteria and microalgae cultures

The antialgal activity of newly synthesized bacillamides against several cyanobacteria and microalgae isolates was screened using a rapid 96-well microplate bioassay. Cultures were exposed to serial dilutions of each bacillamide derivative (0-160 mu g mL(-1)) in the microplate wells and daily optical measurements were used to estimate growth over a 216 h period. Inhibition values (%) were calculated from the estimated growth curves and inhibitory concentrations (IC(50)-216 h) were obtained from the sigmoidal inhibition curves fitted by regression analysis. The effects of bacillamides on cell morphology and ultrastructure were also analysed by light and transmission electron microscopy. In general, the toxic cyanobacteria Microcystis aeruginosa, Aphanizomenon gracile, Anabaena circinalis and Anabaenopsis circularis were much more sensitive to bacillamides then the chlorophytes Ankistrodesmus falcatus and Scenedesmus obliquus. However, clear signs of morphological and ultrastructural changes induced by bacillamide were observed on both cyanobacteria and chlorophytes. Other cyanobacteria, namely the nostocalean Nodularia spumigena and the oscillatorialeans Leptolyngbya sp. and Planktothrix rubescens, exhibit higher tolerances to bacillamides, similar to that shown by different eukaryotic microalgae. Diatoms, on the other hand, proved to be quite as sensitive to most bacillamides as the most affected cyanobacteria. The properties of 5-iodo-Bacillamide (algicide or algistatic) were further investigated. This compound acted as an algistactic agent against eukaryotic algae and, depending on its concentration, acted as either an algicide or algistactic agent against most of the cyanobacteria tested. Although bacillamides cannot be considered as broad spectrum cyanobacterial algicides, different bacillamides might be of use in selectively controlling the growth of particular species of cyanobacteria.FCT-POCI/AMB/60531/200

Effects of tryptamine on growth, ultrastructure, and oxidative stress of cyanobacteria and microalgae cultures

Tryptamine was screened for selective antialgal activity against different cyanobacteria and eukaryotic microalgae. In a rapid 96-well microplate bioassay cultures were exposed to tryptamine concentrations from 0.625 to 20 lg ml-1 and growth was estimated by daily optical measurements over a 216 h period. Inhibitory concentrations (IC50216h) obtained from the sigmoidal inhibition curves showed that tryptamine prevents the growth of most cyanobacteria and eukaryotic microalgae at similar concentrations. However, most of the eukaryotic algae recovered growth after being transferred to new tryptamine-free culture media, while most cyanobacteria showed no growth recovery. Microscopical examination of exposed cells showed no major effects of tryptamine on eukaryotic ultrastructure but showed major-induced alterations on cyanobacteria (disorganization of thylakoid membranes, intratylakoidal vacuolization, increased cytoplasmatic granules, and cell lysis). Biochemical analyses performed on Aphanizomenon gracile (cyanobacteria) and Ankistrodesmus falcatus (chlorophyceae) showed that tryptamine induces an increase in H2O2 production in both cultures. Although no significant changes in catalase activity were detected, both cultures showed an increase in ascorbate peroxidase activity following tryptamine exposure treatments. Interestingly, lipid peroxidation was found to increase only in A. gracile, suggesting that the cellular defence mechanisms triggered by this cyanobacterium were less efficient than the ones triggered by A. falcatus for the removal of reactive oxygen species (ROS). Strong lipid peroxidation in cyanobacteria might lead to irreversible membrane damages which probably prevent these organisms to recover growth after tryptamine exposure. On the contrary, the eukaryotic alga seems to respond quite effectively to tryptamine induced oxidative stress and this would explain the capacity for this organism to recover growth after being exposed to tryptamine