Effects of carbamazepine in aquatic biota

Carbamazepine (CBZ) is one of the most common pharmaceuticals found in the aquatic environment. Here, we reviewed studies in aquatic animals highlighting that CBZ affected ROS homeostasis but also the...

River Reorganization Affects Populations of Dwarf Cichlid Species (Apistogramma Genus) in the Lower Negro River, Brazil

Alterations, such as drainage network reorganization, in the landscape in the Amazon basin influence the distribution range and connectivity of aquatic biota and, therefore, their evolution. River capture is a geomorphic mechanism of network reorganization by which a basin captures large portions of the network of a neighboring basin, thus creating a barrier against species dispersal. In this study, the influence of river capture on the genetic differentiation and structuring of two dwarf cichlids species (Apistogramma pertensis and Apistogramma gephyra) is investigated in two tributaries of the lower Negro River. The analysis of 11 loci microsatellite and three mitochondrial DNA genes (Cytochrome b, Citochrome c Oxidase subunit I and 16S ribosomal RNA) confirmed the populational isolation of two dwarf cichlids species, suggesting that they represent evolutionary significant units (ESU) that have been isolated—probably due to the river capture event. The paleovalley that resulted from the river capture is therefore an important physical barrier that separates the populations of the Cuieiras and Tarumã-Mirim Rivers. The findings herein provide evidence of a mechanistic link between the isolation and differentiation of fish populations and the drainage evolution of the Amazon basin, and indicate that the dynamic geological history of the region has promoted species diversification. The process described here partially explains the high diversity in the genus Apistogramma and the information obtained is beneficial to conservation programs.

Optimizing efforts to restore aquatic ecosystem connectivity requires thinking beyond large dams

Infrastructure-induced fragmentation of riverine ecosystems has prompted the need for more effective aquatic restoration efforts globally. Fragmentation assessments have been extensively undertaken to inform connectivity restoration efforts for fish and other aquatic biota, but they have potentially underestimated the extent of fragmentation by fixating on large dams and overlooking the contribution of other barriers like road crossings and small irrigation structures. The current study addresses this limitation in Mekong region countries (MReCs) of Southeast Asia, by assessing the fragmentation impacts of road crossings and small irrigation structures together with large dams. Our analysis indicates that the basin-scale fragmentation impact of road crossings is similar to that of large dams in MReCs, while small irrigation structures have a far greater impact. These findings raise concerns about the real global extent of aquatic fragmentation, and highlight the need for decision-makers to think beyond dams when attempting to restore connectivity for aquatic biota.

Pesticides Burden in Neotropical Rivers: Costa Rica as a Case Study

Neotropical ecosystems are highly biodiverse; however, the excessive use of pesticides has polluted freshwaters, with deleterious effects on aquatic biota. This study aims to analyze concentrations of active ingredients (a.i) of pesticides and the risks posed to freshwater Neotropical ecosystems. We compiled information from 1036 superficial water samples taken in Costa Rica between 2009 and 2019. We calculated the detection frequency for 85 a.i. and compared the concentrations with international regulations. The most frequently detected pesticides were diuron, ametryn, pyrimethanil, flutolanil, diazinon, azoxystrobin, buprofezin, and epoxiconazole, with presence in >20% of the samples. We observed 32 pesticides with concentrations that exceeded international regulations, and the ecological risk to aquatic biota (assessed using the multi-substance potentially affected fraction model (msPAF)) revealed that 5% and 13% of the samples from Costa Rica pose a high or moderate acute risk, especially to primary producers and arthropods. Other Neotropical countries are experiencing the same trend with high loads of pesticides and consequent high risk to aquatic ecosystems. This information is highly valuable for authorities dealing with prospective and retrospective risk assessments for regulatory decisions in tropical countries. At the same time, this study highlights the need for systematic pesticide residue monitoring of fresh waters in the Neotropical region.

Analysis of Pb and Cd Heavy Metal Contents in Green Mussel (Pernaviridis L.) in Alue Naga Waters, Banda Aceh

Alue Naga waters are a coastal area in Banda Aceh city which is thought to have been exploited due to various human activities. The existence human settlements, tourist spots, fishponds, ports, and places for catching marine biota such as oysters, green mussels and fish are some instances to name a few.This research was conducted in July 2020 using simple random sampling method. Samples of green mussels were taken from a container for cultivation and from the bottom of the stream. Sample analysis was done using Atomic Absorption Spectrophotometer (AAS) at the laboratory of Office for Research and Standardization of Aceh Industries. The heavy metals that were analyzed are Lead (Pb) and Cadmium (Cd). The results showed that the content of Pb found in the cultivated green mussels was <0.0001 mg/Kg and Cd with <0.0002 mg/Kg. The metal content of green mussels found at the bottom of the stream was <0.0004 mg/Kg for cadmium and <0.0001 mg/Kg for lead. The intensity of heavy metal content in the seawater atcultivation locations also did not exceed the quality standard for the stream and aquatic biota with <0.0001 mg/L (Pb) and <0.0004 mg/L (Cd). Therefore, it is safe for human consumption.

Effects of Polymetallic Ore Occurrences on Mercury Accumulation by Aquatic Biota in River Ecosystems

The study represents the data on metal content in the body of stoneflies Perla pallida Guerin-Meneville, 1838 (Plecoptera, Perlidae) and in muscles of the fish family Cyprinidae from the small tributaries of the Belaya River (Republic of Adygea, Northwest Caucasus) with ore mineralization of various metals including mercury. It was found that mercury (Hg) concentrations in stoneflies are corresponds to from the water basins without local Hg sources. Mercury content in stoneflies depends on season and is more intensive in early ontogenesis in winter than in the warm season. Mercury concentration in 0.01–0.72 mg/kg dry weight can cause the pathomorphological changes in the structure of organs and decrease the adaptive potential in competitive population of stoneflies, in general. The Hg concentration reached 0.09–0.69 mg/kg in the studied fish species (bleak, gudgeons, and barbels) and was similar to concentrations in stonefly larvae. This can be related with low size-weight parameters of fishes in samples as wells as with similar feeding patterns of hydrobionts.

Assessment of Corbicula moltkiana Growth by Different Methods on Variation of Substrates in Lake Maninjau, West Sumatera, Indonesia

Corbicula moltkiana is a mussel species in Lake Maninjau and one of the targeted fisheries resources in the lake. This study aimed to determine the feasibility of a controlled growth experiment of mollusk biota in describing their natural growth. The assessment was carried out in areas with different habitats in shore lake, namely sand and gravel-stone substrates. A consecutive 12 month- sampling was carried out from June 2013 to May 2104 using a Surber sampler at a 1-3 m depth were used to assess the wild population growth. Moreover, the growth of the controlled population was observed by rearing various sizes of mussels in artificial substrate namely three small baskets which installed in the shore area with 1-3 m depth at each station for four months. Monthly sampling was carried out to measure the shell length. The growth of C. moltkiana on wild population by VBGF methods show that at the gravel-stone substrate was higher, but the growth a controlled population in artificial substrate seemed in the sand substrate was higher than that in the gravel-stone substrate. The growth of aquatic biota in a controlled system (especially C. moltkiana) does not always reflect similar conditions to their wild growth.