scholarly journals Sensitivity of freshwater species under single and multigenerational exposure to seawater intrusion

2018 ◽  
Vol 374 (1764) ◽  
pp. 20180252 ◽  
Author(s):  
C. Venâncio ◽  
B. B. Castro ◽  
R. Ribeiro ◽  
S. C. Antunes ◽  
N. Abrantes ◽  
...  

Salinization of coastal freshwater ecosystems is already occurring in some regions of the world. This phenomenon raises serious concerns on the protection of coastal freshwater ecosystems, since many of them support and shelter a large number of species and are considered hotspots of biodiversity. This work intended to assess the adverse effects that salinization, caused by the intrusion of seawater (SW), may pose to freshwater organisms. In this study, three specific goals were addressed: (i) to assess if sodium chloride (NaCl) may be used as a surrogate of natural SW at early-stages of risk assessment; (ii) to identify the most sensitive freshwater species to salinity NaCl; and (iii) to determine if increased tolerance to salinity may be acquired after multigenerational exposure to low levels of salinization (induced with NaCl). A total of 12 standard monospecific bioassays were carried out by exposing organisms from different taxonomic groups (Cyanobacteria: one species, Tracheophyta: two species, Rotifera: one species, Arthropoda: two species and Mollusca: one species) to a series of concentrations of NaCl (ranging from 0.95 to 22.8 mS cm –1 ) or dilutions of SW (ranging from 1.70 to 52.3 mS cm −1 ). In general, NaCl exerted similar or higher toxicity than SW, both at lethal and sublethal levels, suggesting that it may be proposed as a protective surrogate of SW for first tiers of salinization risk assessment. Among all tested species, the cyanobacterium Cylindrospermopsis raciborskii , the daphnid Daphnia longispina and the rotifer Brachionus plicatilis were the most sensitive taxa to salinization (EC 50 ≤ 4.38 mS cm −1 ). Given their position at the basis of the food web, it is suggested that small increments of salinity may be enough to induce structural changes in freshwater communities or induce changes in trophic relations. No clear evidences of increased tolerance after multigenerational exposure to low levels of salinity were found. This article is part of the theme issue ‘Salt in freshwaters: causes, ecological consequences and future prospects’.

2007 ◽  
Vol 64 (3) ◽  
pp. 530-538 ◽  
Author(s):  
John M Drake ◽  
David M Lodge

We report results from a study of species in ballast tanks of ships entering the Great Lakes between 2000 and 2002. We collected 1349 individuals from at least 93 unique taxonomic groups, of which approximately half were identified to species. We estimated that the zooplankton assemblage in ballast water destined for the Great Lakes comprised from 200 to 1000 unique taxa consisting of both freshwater and marine species. Between 14 and 39 of these taxa have not yet been recorded from the Great Lakes. Further, 13.9% of individual specimens identified to the species level were from species not previously collected from the Great Lakes. We collected seven nonindigenous freshwater species not currently found in the Great Lakes: Brachionus plicatilis, Cyclocypria kinkaidia, Maraenobiotus insignipes, Microcyclops rubellus, Microcyclops varicans, Neomysis awatchensis, and Paracyclops chiltoni. We found no evidence that ship age, seasonal timing, or age of ballast water affected the abundance of individuals or species in the ballast tanks. To our knowledge, these are the first extrapolations of data from ballast water collections to estimate the rate of species introduction to any ecosystem.


Author(s):  
Astrid Schmidt-Kloiber ◽  
Daniel Hering

Species’ biological traits and ecological preferences are important components to better understand distribution patterns, to help assessing and evaluating the status of freshwater ecosystems and to support biodiversity conservation. In Europe, the Water Framework Directive has been the main driver for the development of ecological assessment systems in recent years, which often use biological traits and ecological preferences of species as source for bioindication. Comprehensive databases compiling such species traits have a longer tradition in the terrestrial realm, but for freshwater organisms, such a database was missing until the establishment of freshwaterecology.info (Schmidt-Kloiber and Hering 2015). The freshwaterecology.info online tool integrates various data sources into a comprehensive database of large-scale distribution patterns, biological traits and ecological preferences of freshwater species, including phytoplankton, diatoms, macrophytes, macro-invertebrates and fishes. The database hosts more than 21,000 European freshwater species/species-groups and information about their specific ecology, and it has more than 1,700 registered users. Based on the availability of funding, the database is constantly being expanded and amended, through experts' contributions, evaluation of recent publications or data analyses. Here we present the database development, its main components as well as some usage examples.


2021 ◽  
Vol 9 ◽  
Author(s):  
Ana C. Costa ◽  
Ana Balibrea ◽  
Pedro M. Raposeiro ◽  
Sofia Santos ◽  
Martin Souto ◽  
...  

Freshwater systems on remote oceanic islands are particularly vulnerable to biological invasions. The case of freshwater ecosystems in the Azores Archipelago is especially relevant considering the islands’ youth and remoteness, and low natural connectivity. This study presents a review of the introduction and presence of non-indigenous freshwater species in the Azores, retrieved from various historical records, paleoenvironmental reconstructions, published records, and field data from two decades of the Water Framework Directive (WFD) monitoring programs. At least 132 non-indigenous freshwater species have successfully established in the Azores, belonging to several taxonomic groups: cyanobacteria (10), synurophytes (1), desmids (1), diatoms (20), plants (41), invertebrates (45), amphibia (2), and fishes (12). Intentional and accidental introductions have been occurring since the establishment of the first human settlers on the archipelago, impacting freshwater ecosystems. The first reported introductions in the Azores were intentional fish stocking in some lakes. Non-deliberate introductions have recently increased through transport-contaminants (51%) associated with the aquarium trade or agricultural products. In the Azores, the highest number of non-indigenous species occur on the largest and most populated island, São Miguel Island (116), followed by Flores (68). Plants constitute the most representative group of introduced species on all islands, but invertebrates, diatoms, and fishes are also well established on most islands. Among invertebrates, non-indigenous arthropods are the most well-established group on all islands except on the smallest Corvo Island. Many non-indigenous species will likely benefit from climate change and magnified by globalization that increases the probability of the movement of tropical and subtropical species to the Azores. Present trends in international trade, importations, and enhanced connectivity of the archipelago by increasing flights and shipping will probably promote the arrival of new species. Augmented connectivity among islands is likely to improve non-indigenous species dispersal within the archipelago as accidental transportation seems to be an essential pathway for non-indigenous freshwater species already present in the Azores.


2021 ◽  
Vol 4 ◽  
Author(s):  
Álvaro Fueyo ◽  
Javier Granero-Castro ◽  
Beatriz Villazán Peñalosa ◽  
Yaisell Borrell Pichs

The Water Framework Directive (WFD) monitoring requires the use of stressor-specific Multimetric Indices, intercalibrated and validated at river basin level, such as the IBMWP, which is one of the most widely used indices for the biomonitoring of rivers in the Iberian Peninsula. This qualitative index is based on the identification mainly at family level of 125 groups of macroinvertebrates. Currently, molecular biomonitoring systems (biomonitoring 2.0) is widely considered as a good alternative to conduct water quality assessments. The problem comes with the requirement of having complete DNA sequences databases for the targeted species within the indicator groups. In order to know the percentage of sequence coverage of the different taxonomic groups, is needed to know the number of freshwater species in each group. The fact that currently it is only necessary to identify them morphologically at family level to calculate the index means that there are no exhaustive lists of lower taxonomic ranges. In this study, we have studied the available taxonomic databases at species level for river macroinvertebrates in the Iberian Peninsula. For this purpose, species geographically referred to the Iberian Peninsula were extracted from three sources: two European (Freshwaterecology.info database and Weigand et al. (2019)) and one Iberian database/list (Múrria et al. 2020). The resultant species list was compared with GBIF (Global Biodiversity Information Facility) using its tool “Species Matching” to find synonyms and fuzzy names. The similarities and differences between databases were studied (considering the synonyms but not the fuzzy names) and a new list of 3586 species was constructed. Our analysis revealed that from 125 taxonomic groups covered by the IBMWP, there are no species collected for 11 of them (9%) and for another 34 groups (27%) there are less than 5 species collected in the databases. Then, using the BAGS software, all sequences of the mitochondrial gene COX1 were mined from BOLD database. From the 3586 species in the list, only 1900 (53%) have at least one sequence in BOLD. Therefore, conducting biomonitoring 2.0 in Iberian freshwater ecosystems is far from effective today. We need to overcome two big obstacles to reach the goal of using molecular biomonitoring in the Iberian Peninsula: a complete taxonomic list of quality indicators species by groups, and to sequence DNA barcodes from all relevant species.


2003 ◽  
Vol 154 (7) ◽  
pp. 254-257
Author(s):  
Ernst Steiner

In recent years public forest owners in the canton of Argovia have carried out considerable structural changes. The positive consequences to the accounts arising from these changes can be confirmed and documented using a number of various measurements from the forest accounts. Until 1999 the results of structural changes compensated for the decrease in wood revenues, even managing in some cases to move from loss to profit. The falls in profit following the catastrophic damage caused by the hurricane Lothar in December 1999 also meant falling accounts. Even in internationally comparable enterprise structures, the survival of forest enterprises is not assured at these low levels. Against a background of, above all, falling subventions without corresponding compensation, further structural changes are unavoidable. Such changes, however, can only lead to success if value is added along the entire production chain and the branch of forest and wood management is able to compete internationally.


Parasitology ◽  
1999 ◽  
Vol 117 (7) ◽  
pp. 205-212 ◽  
Author(s):  
C. J. GIBSON ◽  
C. N. HAAS ◽  
J. B. ROSE

Throughout the past decade much research has been directed towards identifying the occurrence, epidemiology, and risks associated with waterborne protozoa. While outbreaks are continually documented, sporadic cases of disease associated with exposure to low levels of waterborne protozoa are of increasing concern. Current methodologies may not be sensitive enough to define these low levels of disease. However, risk assessment methods may be utilised to address these low level contamination events. The purpose of this article is to provide an introduction to microbial risk assessment for waterborne protozoa. Risk assessment is a useful tool for evaluating relative risks and can be used for development of policies to decrease risks. Numerous studies have been published on risk assessment methods for pathogenic protozoa including Cryptosporidium and Giardia. One common notion prevails: microbial risk assessment presents interesting complications to the traditional chemical risk assessment paradigm. Single microbial exposures (non-threshold) are capable of causing symptomatic illness unlike traditional chemical exposures, which require a threshold to be reached. Due to the lack of efficient recovery and detection methods for protozoa, we may be underestimating the occurrence, concentration and distribution of these pathogenic micro-organisms. To better utilize the tool of microbial risk assessment for risk management practices, future research should focus in the area of exposure assessment.


2018 ◽  
Vol 69 (7) ◽  
pp. 1159 ◽  
Author(s):  
P. Bayliss ◽  
C. M. Finlayson ◽  
J. Innes ◽  
A. Norman-López ◽  
R. Bartolo ◽  
...  

The internationally important river–floodplains of the Kakadu Region in northern Australia are at risk from invasive species and future sea-level rise–saltwater inundation (SLR–SWI), requiring assessments of multiple cumulative risks over different time frames. An integrated risk-assessment framework was developed to assess threats from feral animals and aquatic weeds at three SLR-scenario time frames (present-day, 2070 and 2100) to natural (magpie goose habitats), cultural (indigenous hunting–fishing sites) and economic (tourism revenue less invasive species control costs) values. Probability density functions (pdfs) were fitted to spatial data to characterise values and threats, and combined with Monte Carlo simulation and sensitivity analyses to account for uncertainties. All risks were integrated in a Bayesian belief network to undertake ‘what if’ management-scenario analyses, and incorporated known ecological interactions and uncertainties. Coastal landscapes and socio-ecological systems in the region will be very different by 2100 as a result of SLR; freshwater ecosystems will transform to marine-dominated ecosystems and cannot be managed back to analogue conditions. In this context, future invasive-species risks will decrease, reflecting substantial loss of freshwater habitats previously at risk and a reduction in the extent of invasive species, highlighting the importance of freshwater refugia for the survival of iconic species.


2021 ◽  
Vol 18 (1) ◽  
pp. 52-56
Author(s):  
S.O. Ajagbe ◽  
R.O. Ajagbe ◽  
O.S. Ariwoola ◽  
F.I. Abdulazeez ◽  
O.O. Oyewole ◽  
...  

Cichlids are highly abundant and commercially important fish in freshwater ecosystems in Nigeria. This study examined the diversity and abundance of cichlids in Ikere Gorge Reservoir. Four fishing villages were randomly selected from 12 fishing villages in Ikere Gorge Reservoir as sampling sites. Cichlids were sampled randomly and examined from fishermen catch in each selected fishing village; were identified with appropriate keys; the weight and abundance of the catches were recorded. The data obtained was subjected to descriptive statistical analysis using SPSS (Version 20.0) software to determine the abundance of fish species. Fish species diversity was carried out by using Palaeontological Statistics (PAST). Eight species of cichlids were sampled in Ikere Gorge but Sarotherodon galilaeus was the most abundant species while the least abundant species was Pelmatolapia mariae. It was observed that, cichlids were  abundant in rainy season than in the dry season. Likewise, cichlids were abundant in Ikere-gorge reservoir but they have low diversity. This may be as a result of unsustainable fishing pressure and deforestation of riparian forest and sedimentation in Ikere-gorge reservoir. Therefore, to maintain sustainable fishing activities and improve cichlids population in Ikeregorge reservoir, unsustainable activities in and around Ikere Gorge reservoir should be put under control. Keywords: Cichlidae; freshwater species; dominant; Sarotherodon galilaeus; Pelmatolapia mariae.


2008 ◽  
Vol 51 (4) ◽  
pp. 633-641 ◽  
Author(s):  
Naithirithi Tiruvenkatachary Chellappa ◽  
Sarah Laxhmi Chellappa ◽  
Sathyabama Chellappa

The aim of this work was to study the eutrophication in the tropical freshwater ecosystems and the consequent cyanobacterial bloom formation and economical damage to fisheries and harmful effects to public health. Mass fish mortality due to toxin producing cyanobacterial blooms was registered during December 2003 in Marechal Dutra Reservoir, Acari/RN, Northeast Brazil. Phytoplankton and fish samplings were carried out on alternate days during the episode of fish mortality and monthly during January to June 2004. The cyanobacterial toxin was identified and quantified from the seston samples and liver of the dead fishes using the standard HPLC method. The results indicated that the toxic blooms of Cylindrospermopsis raciborskii and Microcystis aeruginosa were persistent for two weeks and represented 90% of the phytoplankton species assemblages. The lethally affected fishes were Oreochromis niloticus, Plagioscion squamosissimus, Cichla monoculus, Prochilodus brevis, Hoplias malabaricus and Leporinus friderici. The microcystin levels varied from 0.07 to 8.73µg L-1 the seston samples and from 0.01 to 2.59µg g-1in the liver samples of the fishes during the bloom period.


Sign in / Sign up

Export Citation Format

Share Document