Hydrobiologia最新文献

Solar photovoltaic (PV) generation is burgeoning as global economies pursue decarbonization goals. To meet the surge in solar energy demand, deployment of PV panels on water surfaces has emerged as an attractive option. Despite the potential advantages associated with floating PV (FPV) systems, current understanding of their impact on aquatic life remains scarce. Here, we use the Preferred Reporting Items for Systematic Review and Meta-analysis methodology to provide a systematic review of FPV effects on aquatic organisms. Our search yielded 24 studies selected for qualitative analysis—most of which were performed in small-scale artificial ecosystems. We identified 39 variables across 12 artificial taxonomic groups. The most commonly reported effect was the reduction of chlorophyll-a in the water. Additionally, there is growing evidence that FPV has indirect effects on various groups of aquatic organisms. Enhancing current understanding of ecological consequences of FPV systems on aquatic biodiversity is urgent given the industry’s rapid expansion, and developing strategies for monitoring, controlling and predicting water quality impacts is necessary. This review provides a foundation for future studies and can assist in the development of strategies for balancing impacts and benefits of FPV systems.

The World Register of Marine Species (WoRMS) started in 2007 with the question “how many species live in our oceans?”. Now, a little over 15 years later, WoRMS is able to answer several questions related to marine species discovery rates and provides a dynamic number of existing marine species, based on the information provided by hundreds of taxonomic experts worldwide, who have proven to be diverse and dynamic. We present basic statistics on marine species discovery rates based on the currently available content of WoRMS, as well as insights in the day-to-day activities and dynamics of our editorial board and the progress made so far on the content priorities as defined by the WoRMS Steering Committee. As for all dynamic systems, WoRMS is not complete and faces challenges. As an endorsed project of the UN Ocean Decade, WoRMS aims to tackle a number of these challenges and knowledge-gaps by 2030, including detailed documentation of authorships and original descriptions, and will provide continuous support to all marine initiatives, programs and projects that rely on WoRMS as an authoritative classification and catalogue of marine names.

This study pioneers the evaluation of toxicity in the Coromandel stream, located in the southeastern region of Brazil, highlighting the essential role of ecotoxicology in informing environmental management decisions. We employed bioindicators to assess the water quality across multiple collection points along the stream, focusing on its physical, chemical, and ecotoxicological characteristics. The investigation utilized Allium cepa seeds and Dendrocephalus brasiliensis nauplii to conduct acute ecotoxicological tests, examining cytotoxic and genotoxic effects, including the mitotic index and micronuclei frequency for A. cepa and immobility rates for D. brasiliensis. Our findings reveal significant pollution impacts, particularly in areas affected by residential and industrial activities, where increased immobility in D. brasiliensis and heightened genotoxic potential were observed. These outcomes indicate deteriorating water quality and underscore the urgency for targeted environmental interventions. Real-time monitoring further identified critical alterations in water parameters, underscoring the stream sections with significant anthropogenic influence as hotspots for pollution and toxic risk. This research underscores the importance of integrated ecotoxicological assessments in detecting and addressing environmental threats in freshwater ecosystems.

La Plata Basin, the fifth-largest basin in the world, includes areas of Argentina, Bolivia, Brazil, Paraguay, and Uruguay and is subjected to intensive human activities such as agriculture, mining, and global trade. The basin hosts 83 native bivalves (Hyriidae, Mycetopodidae, Cyrenoididae, and Sphaeriidae), including 29 endemic and at least 3 non-native species (Cyrenidae and Mytilidae). For their role as filter feeders and their dominance in biomass in benthic freshwater ecosystems, freshwater bivalves play a key role in the resilience of aquatic ecosystems. In this review, we discuss the six major global change threats to freshwater ecosystems in the Anthropocene (climate change, flow regulation, pollution, land-use change, invasive species, and overexploitation) using freshwater bivalves of La Plata Basin as a model in South America. Future directions to properly understand the effects of global change and suggestions for the conservation of the freshwater bivalves in the basin are stated.

Exploring the seasonal dynamics of different components of biodiversity (alpha, beta, and zeta) and identifying the factors driving these patterns can help to reveal the health conditions and changes of ecosystems across different seasons. Seasonal differences in coastal fish biodiversity components were determined based on data of species abundance, traits, and mitochondrial genes. We then used multiple models to assess the relative importance of environmental and geographic variables in shaping the spatial patterns of different components of diversity. The results showed that the variation patterns of alpha diversity indices among seasons were inconsistent. All beta diversity indices showed significant seasonal variations. The rate of zeta diversity decline was highest in winter, and the compositional turnover showed no significant variations among the other three seasons. In spring, longitude was the most important factor influencing variations in alpha and beta diversity, while sea surface temperature and distance from mainland were important drivers for fish zeta diversity. Distance from mainland, sea surface temperature, and salinity were the most critical factors shaping the spatial pattern of diversity in summer, autumn, and winter, respectively. Our results suggest that environmental and geographic factors play an important role in shaping the patterns of coastal fish diversity.

Diatoms have been extensively used as paleolimnological indicators because they acutely respond to changes in their environment. Diatom assemblages recovered from sediment cores are a mixture of benthic and planktic assemblages that may have been transported away from their source environment or deposited near their habitat. Thus, there is an inherent variability in the diatom deposition across the sediments of a lake. With the aim of characterizing this variability and identifying how it may affect palaeoecological reconstructions, we identified diatom communities and assemblages from a series of sediment cores, surface sediment samples, and samples from different lake microenvironments (submerged macrophytes, sediments, marsh, meadow and attached algae). Comparing the sediment cores, we found differences in the timing of diatom assemblage shifts, which we attribute to differences in the diatom distribution in the sediments. Additionally, we identified gradients of diatom deposition where benthic and tychoplanktic diatoms dominate assemblages near shorelines and planktic assemblages dominate toward the lake center. We attribute benthic and tychoplanktic distribution to distance to the source and recognize that diatoms associated with modern microenvironments are underrepresented in the sediments because of their attachment to a substrate.

Functional traits are promising features for biomonitoring in freshwater ecosystems. Here, we focused on 23 floodplain lakes to evaluate the responses of taxonomic and functional traits of freshwater mollusks to the loss of lateral hydrological connectivity (LHC). Our results revealed that the disconnected lakes (DLs) had significantly lower species richness of most functional trait categories of mollusks compared to the connected lakes (CLs). For percentages of species richness, only percentages of burrowers and thick-shelled species were significantly lower in DLs than CLs, while percentages of thin-shelled and small-sized species were higher in DLs. Therefore, there has been a shift toward assemblages with thin-shelled and small mollusks following LHC loss. We also found that key environmental variables affecting taxonomic and functional composition were connectivity, lake area, aquatic vegetable coverage, and water quality. Moreover, the functional composition of all Mollusca, Gastropoda, and Bivalvia were all better explained (explained variation ranged from 0.462 to 0.684) by environmental factors compacted with taxonomic composition (0.213–0.401). Connectivity was the most important factor affecting functional trait composition, whereas area was the most important variable for taxonomic composition. Thus, the trait-based approach based on mollusks was more sensitive in assessing the impacts of disconnection than the taxonomy-based approach.

Understanding the trophic interactions and coexistence processes among waterbirds in floodplain ecosystems is of fundamental ecological importance. In the upper Paraná River floodplain, we assessed the diet of five sympatric waterbird species (Ardea alba, Ardea cocoi, Egretta thula, Nannopterum brasilianum, and Nycticorax nycticorax) and tested their differences in the diet, in addition to food overlap, differences in trophic niche breadths and stratum in the water column where they forage. The waterbirds’ stomachs were collected quarterly on the upper Paraná River floodplain, analyzed under a stereomicroscope, and the food items were identified. Only Egretta thula was classified as omnivorous, consuming various food resources, including insects, decapods, and fish. The other species were piscivorous, but differed in the types of prey. Food overlap was higher in the piscivorous species, but they exhibited high trophic niche breadth. The piscivorous waterbirds employ different strategies for exploiting food resources that allow species coexistence in the floodplain, avoiding direct competition. Our results highlight the importance of waterbirds as connectors across diverse environments, especially aquatic-terrestrial ecosystems. Since these waterbirds’ diet relies on fish, effective conservation and management strategies targeting fish communities are fundamental to maintaining biodiversity and functionality within the upper Paraná River floodplain.