Aquatic Ecology最新文献

We identified publication trends and methodological changes in polychaete ecotoxicological studies since the review carried out by Reish and Gerlinger (Bull Mar Sci 60:584–607, 1997) using a classic review approach. We also carried out a meta-analysis to identify the overall effect of the type of pollutants (e.g., hydrocarbons, metals, pesticides) and to test the consistency of their effect at different levels of analysis (e.g., biochemical, physiological, behavioral) using 14 different biological responses (e.g., bioaccumulation, tolerance, enzymatic activity). A total of 136 articles met the selection criteria and were analyzed for the classic review. Main findings include: (1) studies focused on the effects of metals (48%), hydrocarbons (32%), and pesticides (20%); (2) sublethal effects were more frequent; and (3) the nereidid species Hediste diversicolor was the most studied species. For the meta-analysis, 27 articles met the selection criteria and a total of 168 effect sizes were calculated. The results from the generalized linear mixed models (GLMMs) indicated that the hydrocarbons have the strongest effect in polychaetes, while the most sensitive metric is behavior. Enzymatic activity and mortality represented the most sensitive biological responses to estimating the magnitude and direction of the effect. Finally, the tendencies observed in the classic review did not represent the strongest effects in the GLMMs.

Dissolved rare earth elements (REE) can reflect the environmental changes in river systems and trace the mixing processes between rivers and the ocean at the estuary. In this study, the dissolved REE concentrations were measured in the river and estuary of the Jiulong River, which supplies drinking water to about one-third of the population of southern Fujian Province. The results showed the total dissolved REE varied within a wide range, from 19.94 to 2041.58 ng/L. (La/Yb)_N varied between 0.15 and 1.03 in the Jiulong River, and apparent fractionation between LREE (depleted) and HREE (enriched) was noticed, especially at the estuary. The fluctuations of dissolved REE concentrations were mainly related to the riverine pH and the complexation with colloids and ions. Higher dissolved REE concentrations in the Xixi River were attributed to the application of chemical fertilizer. The relatively lower concentrations in the estuary may result from salt-induced flocculation, and the preferential removal of LREE resulted in lower (La/Yb)_N and more pronounced HREE enrichment in the estuary. The Ce anomalies observed in the Jiulong River were associated with redox conditions, while positive Eu anomalies were linked to the dissolution of the rocks within the basin. The distinct Gd anomalies were observed in N4 and W10 flowing through the urban area, suggesting the point source inputs from the wastewater associated with anthropogenic activities. This study highlights the effect of natural processes and human activities on dissolved REE in fluvial-estuarine systems, which should raise concerns regarding anthropogenic inputs of REE to rivers and coastal regions.

The eastern Mediterranean Sea is facing an unprecedented crisis due to the introduction and spread of alien species through the Suez Canal. Early detection and distribution monitoring of these species has been recently facilitated using social media and citizen science. The project “Is it Alien to you? Share it!!!” recorded over 840 observations for about 100 marine species in Cyprus (eastern Mediterranean Sea) primarily via a dedicated social network group. Through the utilization of morphological and molecular approaches on materials posted by a local fisher, this study provides the first records of Ixa monodi and Myra subgranulata in Cyprus and additional records of Macrophthalmus indicus for the island. These sightings confirm the effectiveness of citizen science in monitoring species distribution shifts. The cooperation of scientists with fishers has the potential to enhance surveillance, while concurrently increase awareness and position citizens as conservation leaders.

Monitoring the morphological traits of farmed fish is pivotal in understanding growth, estimating yield, artificial breeding, and population-based investigations. Currently, morphology measurements mostly happen manually and sometimes in conjunction with individual fish imaging, which is a time-consuming and expensive procedure. In addition, extracting useful information such as fish yield and detecting small variations due to growth or deformities, require extra offline processing of the manually collected images and data. Deep learning (DL) and specifically convolutional neural networks (CNNs) have previously demonstrated great promise in estimating fish features such as weight and length from images. However, their use for extracting fish morphological traits through detecting fish keypoints (landmarks) has not been fully explored. In this paper, we developed a novel DL architecture that we call Mobile Fish Landmark Detection network (MFLD-net). We show that MFLD-net can achieve keypoint detection accuracies on par or even better than some of the state-of-the-art CNNs on a fish image dataset. MFLD-net uses convolution operations based on Vision Transformers (i.e. patch embeddings, multi-layer perceptrons). We show that MFLD-net can achieve competitive or better results in low data regimes while being lightweight and therefore suitable for embedded and mobile devices. We also provide quantitative and qualitative results that demonstrate its generalisation capabilities. These features make MFLD-net suitable for future deployment in fish farms and fish harvesting plants.

Desmids are one of the most representative groups of algae in oligo-mesotrophic aquatic environments. They respond to environmental changes and can be used as indicators of water quality. We evaluated changes in the structure of desmid communities on emergent macrophytes in relation to environmental conditions at a spatial scale in two rivers in a tropical urban basin in the State of Bahia, Brazil. Sampling was carried out every two months for one year at five fixed stations. Changes in the desmid community structure were associated with variations in limnological conditions, which differed between the sampling stations. We observed increases in total phosphorus concentration and conductivity from upstream to downstream, which influenced the changes in desmid community structure. Desmid richness and total density were higher in urban, recreational, and more preserved areas. In conclusion, phosphorus availability associated with land use and urbanization influenced desmid community structure variability in coastal plain rivers.

Rushes belong to the group of plants commonly found in water bodies, fulfilling many important functions. However, their presence depends both on features of the immediate surroundings and morphology of the lake. At the same time, rush presence can be an indicator of important features of the surrounding habitats. The aim of this study was to determine the impact of shoreline and buffer zone development on the attributes of rushes. Indications of lake features affected the rushes most strongly. We analysed 65 lakes located in the eastern part of Poland, within the boundaries of the Łęczna-Włodawa Lake District. The multidimensional analyses identified factors that most strongly determined the development of lake rushes in Polesie Lubelskie. The presence of peat bogs, scrubland communities, and wet meadows favoured the development of rushes. Among the morphometric characteristics of lakes, the depth and frequency of water mixing were significant, as well as the trophic level of the lake. Moreover, models describing scenarios for further development of rushes were developed. They predicted that the surface area of the rushes in the lake will increase (average of 0.288 ha) when the peatlands become overgrown 1 ha, and the share of dry (drained) meadows will increase (average of 0.996 ha) in the buffer zone. The increase in the density of rushes will take place if the share of buildings and scrub communities increases both in the buffer zone and shoreline area.

The role of groundwater as a driver of spatial and temporal heterogeneity of ecological conditions in streams is not well understood, particularly at larger spatial scales. To evaluate the association between groundwater and ecological communities and processes, we assessed stream biofilm communities (biomass and diatom assemblage composition) and cellulose decomposition over four seasons in 19 reaches with varying amounts of groundwater input in a headwater stream network in southern Ontario, Canada. Seasonal variation was found to drive diatom assemblage composition and cellulose decomposition among seasons. Moreover, there were clear seasonal patterns in taxa succession in the diatom assemblages where the dominant taxa shifted in accordance with ecological preferences of the taxa. Within season assessments of stream biofilms among individual reaches showed that biomass, diatom assemblage composition, and cellulose decomposition were not associated with amount of groundwater input. The lack of concordance between groundwater influence and stream biofilm condition suggests that the groundwater signal may have been overwhelmed by surface water influences, such as nutrients and thermal effects, at the reach scale. Our findings also demonstrate the importance of assessing stream biofilm communities and cellulose decomposition in multiple seasons to identify and understand discrete shifts in ecosystem conditions of temperate streams.

Urbanization is one of the main causes of fragmentation and loss of habitat under native diversity, being the green areas a key space to shelter and protect species inside the cities. In aquatic ecosystems, subtle changes can lead to a rapid decrease in the species populations. Strengeriana fuhrmanni is a species endemic to west-central Colombia that lives in clear waters, and is sensitive to environmental changes. This work aimed to determine the effects of green areas and the urbanization process in the natural populations of S. fuhrmanni in the mountains of Manizales (Colombia) and whether different types of green areas serve as the refuges for the species. For the occurrence records, collections were carried out through active search in streams, and specimens from the biological collection were analyzed. An analysis of niche modeling and quantification of environmental spaces in the city was carried out, based on the occurrences of the species in the streams. The modeling showed that S. fuhrmanni was widely distributed in the streams of Manizales city; however, the fragmentation of the environment, through urbanization, restricted the population. Regarding the quantification of environmental spaces, this species is occupying less than 50% of its original area. Finally, we emphasize the importance of the green spaces for the remaining populations of S. fuhrmanni, as the streams are still conserved in these areas and provide conditions for their occurrence. Given the rapid urbanization process, it is important to study biodiversity inside these areas to understand how this process affects species, in special endemic ones.