Morpho-functional Groups Research Articles

Effects of the Floc & Sink technique on the biomass and composition of phytoplankton morpho-functional groups using natural ballasts

Effects of the Floc & Sink technique on the biomass and composition of phytoplankton morpho-functional groups using natural ballasts

Do longsnout seahorses Hippocampus reidi (Syngnathiformes: Syngnathidae) have a holdfast preference?

Abstract Coastal systems encompass a range of ecotones that are important for fish species, providing diverse micro-habitats and grounds for foraging, protection from predation, reproduction and areas for recruitment. However, most of these systems face major threats from human activities. Considering the increasing levels of human disturbance in coastal ecosystems, understanding fish-habitat associations may provide important insights into patterns of species occurrence and distribution in human-impacted systems, which can support the development of effective conservation and management measures. In this context, we investigated the relationship between seahorses (Hippocampus reidi) and both habitat complexity and different holdfast species, to determine possible variation between locations and among seasons. Data were obtained from the rocky reefs of Guanabara (Urca Beach) and Sepetiba (Duas Irmãs Island) bays, in southeastern Brazil. Seahorses were counted, and the holdfast being used by each individual was recorded and identified to species or assigned to a morphofunctional group. The beaches differed in holdfast composition and morphofunctional groups, yet sharing some morphofunctional groups. Seahorses were more frequently associated with branching holdfasts at both sites, and also with foliaceous and massive. Association with algae were particularly found in Urca, while the coral Carijoa riisei in Duas Irmãs Island.

Assessment of macroalgal communities on shallow rocky reefs in the Aegean Sea indicates an impoverished ecological status

Mediterranean rocky reefs are undergoing regime shifts, from a structurally complex and diverse state dominated by canopy- forming macroalgae to a degraded one characterised by low-lying turf or encrusting macroalgal species, due to increased anthropogenic pressure and climate change. Using data gathered from 89 sites across the entire Aegean Sea, this study aims to provide the most comprehensive health status assessment of shallow rocky reefs in the area, based on macroalgal community structure. Overall, 2520 benthic images were collected through photoquadrat sampling at 0, 5 and, 15 m depth. Five macroalgal and seven invertebrate morphofunctional groups, along with four substrate categories, were considered for community structure description. Health status was assessed using the reef-EBQI and EEI-c indices. Results indicate turf as the most widespread macroalgal group (36.8% average area cover), followed by encrusting calcareous (16.6%), shrubby (12.7%), articulated calcareous (8.9%), and canopy-forming algae (3.7%). Bare rock also occupied a substantial surface area (9.0%) with highest cover (13.8%) at 5 m. The area cover of canopy-forming algae was particularly low, ranging from 10% at 0 m to 0.1% at 15 m depth, on average. All depths pooled, according to the reef-EBQI index, the ecological status of the Aegean Sea was estimated to be ‘Bad’, mainly due to the bad ecological status of the 5 and 15 m stations. At 0 m depth, the status of the Aegean Sea was ranked ‘Moderate’ according to the reef-EBQI index and ‘Good’ according to the EEI-c index. The results underline the importance of considering a wide depth range when assessing the health status of rocky reef communities.

Spatial distribution of phytoplankton in the Serezha River (Nizhny Novgorod Region)

The investigation presents the results of studies of plankton in the area of the middle course of the riverSerezha in 2019. The floristic diversity of phytoplankton was characterized, its abundance and biomass were estimated, and the change in the morpho-functional groups of phytoplankton along the river was shown. The influence of some physical factors on the development of planktonic algae is considered. The water quality of this section of the watercourse was assessed by phytoplankton biomass, as well as using the community index and the Pantle-Bucksaprobity index.

Determinantes locais e regionais da comunidade fitoplanctônica em barragens de água do bioma Cerrado

Abstract Aim Based on a study comprising water reservoirs within the Brazilian Cerrado biome, we seek to answer the following question: how does phytoplankton communities respond to environmental, landscape, and spatial predictors? We expected local predictors to be the main factors structuring the communities. Since phytoplankton has high dispersal capacity, the geographical distance would be of minor importance. Methods: We collected phytoplankton samples from 40 water reservoirs in the rainy season and 37 reservoirs in the dry season. We performed a partial Redundancy Analysis (pRDA) to evaluate the factors influencing the variation in the composition of phytoplankton communities. Results We found that spatially structured environmental factors were controlling phytoplankton communities at the rainy season, whereas landscape was the main predictor in the dry season. On the other hand, phytoplankton morphofunctional groups were influenced only by local predictors. Conclusions We demonstrated that phytoplankton dynamics differs between rainy and dry seasons, and that distinct predictors affect phytoplankton communities over seasons.

Algal epibiont species on Chiton articulatus (Mollusca: Polyplacophora) from a rocky intertidal coast from the Mexican Tropical Pacific

Chiton articulatus, a mollusk endemic to the Mexican Pacific, is a species whose ecological associations with the algae that colonize it are not well known. This work describes the epibionts observed on the shells of this species. We collected chitons in the rocky intertidal of 2 localities in the state of Guerrero, Mexico. Sixty-two chitons were collected that had 50 species of algae. The best represented family was Cladophoraceae with 10 species. Of the total number of specimens, 26 had epibionts whose distribution on the shell was different: 11 species on the valves, 17 on the suture, 1 on the belt, and 22 species shared in the first 2 zones. Five morphofunctional groups of algae were recognized: microscopic, filamentous, crustose, foliose and corticated filaments, with a predominance of filaments. A relationship was found between the size of the chitons and the percentage of algal cover. Studies like the present one are important due to the interaction between both organisms, since chitons offer surfaces of easy colonization for algae. Furthermore, records of species that do not commonly appear in floristic inventories can be found on these.

Bi- and three-dimensional fractal analysis of the brown seaweed Gongolaria montagnei and their relationship with gastropod molluscs assemblage

Habitat complexity is one of the main influences on biodiversity in marine environments, particularly in coastal areas where foundation seaweeds provide substrate for highly diverse communities. We studied the 2D and 3D fractal dimensions of Gongolaria montagnei (Fucales) over the vegetative season and examine their relationship with the abundance, species richness and morpho-functional groups of the gastropod associated. Overall, the 3D fractal analysis method used here better describes seaweeds structural complexity compared to the traditional 2D fractal analysis, as highlighted by the higher relationship with gastropod assemblage associated to the alga in terms of abundance, number of species and morpho-functional groups. We propose this new method as a valuable tool for understanding the relationship between seaweeds and associated fauna, which is critical for gaining a better understanding of the role that algal species play in a specific habitat and the consequences of their loss.

Using null models and species traits to optimize phytoplankton monitoring: An application across oceans and ecosystems

Phytoplankton assemblages are privileged descriptors of the ecological status of marine ecosystems regularly included in routine monitoring programmes. The high spatial and temporal variability of phytoplankton and the intrinsic difficulties of species identifications, however, combine in making reiterate assessments of this component of marine biota particularly demanding. Coarse levels of taxonomic resolution (e.g., genus, family) or morpho-functional categories have been proposed to reduce identification efforts or to ease the analysis of phytoplankton assemblages for monitoring purposes, although with contrasting outcomes. A major issue is that, in the absence of control for the loss of information associated to these alternative approaches, their application may lead to poor representations of genuine spatial and/or temporal patterns of assemblages in relation to natural and anthropogenic sources of variation. We provided a new approach to reduce the efforts required to analyse phytoplankton assemblages that integrate morpho-functional classification of phytoplankton with the use of null models to estimate the consequent loss of information on species-level community patterns. Null models for information loss were built by randomly grouping the original species variables into a progressively decreasing number of groups, in order to identify the minimum number of aggregate variables needed to detect community patters as at species level. Aggregate variables were then defined as morpho-functional groups, by grouping species on the basis of a combination of morpho-functional traits, including general taxonomy, cell size, shape, elongation and complexity. We applied the approach to six case studies investigating the response of phytoplankton assemblages from marine and transitional water ecosystems under different environmental settings in areas spanning the world’s ocean, including coral atolls, mangroves, estuaries, coastal lagoons and inlets. The approach allowed obtaining parsimonious sets of morpho-functional groups, which were suitable to detect changes in phytoplankton assemblage structure as at species level in all case studies. Trait-based approaches to phytoplankton research and monitoring are crucial to shed light on processes underlying phytoplankton community assembly and dynamics in the face of global change. In this perspective, our framework incorporates cost-effectiveness, instances from traditional monitoring programmes aiming at the detection of community patterns, and the current need for a deeper understanding of functional responses of phytoplankton to environmental drivers.

Comparison of three functional classification approaches to characterize phytoplankton response to environmental heterogeneity: a case study in NE China wetlands

Functional classification is widely recognized as an important approach for characterizing phytoplankton community response to environmental change in freshwater ecosystems. However, there are few studies of that type examining the northeast (NE) China wetlands. The study aimed to evaluate the capacities of phytoplankton functional groups (FGs), morpho-functional groups (MFGs), and morphology-based functional groups (MBFGs), to characterize phytoplankton response to environmental heterogeneity in two wetlands with different nutrient levels. Water quality variables and phytoplankton were examined in the Longfeng and Hulanhe wetlands located on the Songnen Plain, NE China, in 2013. Multivariate analyses (RDA) were performed to compare three functional classification approaches to environmental heterogeneity. Our results revealed that all three functional classification approaches (FGs, MFGs, and MBFG) could characterize the phytoplankton community response to environmental heterogeneity. MBFG had the highest cumulative percentage variance of species composition. We suggest using MBFG as a routine tool to characterize environmental heterogeneity in wetlands NE China. Furthermore, total nitrogen (TN), total phosphorus (TP), electrical conductivity (EC), and pH were key predictors for regulating the ecological distribution of the phytoplankton community pattern in the study area. This study further highlights that MBFG is a relevant tool in assessing ecological health in wetland ecosystems.

Geniculate vs. nongeniculate coralline algae: different responses to stress are also related to morphology

The response of algae to stressors that affect their survival and growth appears to be strictly related to their dimension and shape. Coralline algae (Corallinophycidae, Rhodophyta) show a variety of morphological types that may play a role in their tolerance to stressful conditions. Nevertheless, only a few studies have investigated their response to multiple stressors when grouped by morphology. The aim of this work was to investigate the performance of the 2 main morpho-functional groups of coralline algae (nongeniculate and geniculate) in response to different stressors acting simultaneously (presence of fleshy macroalgae and/or benthic mucilage and sediment deposition). For this purpose, a manipulative field experiment was conducted on superficial rocky substrata (subtidal, 0.5 m depth) in the Tavolara Punta Coda Cavallo Marine Protected Area, Sardinia, in 2016-2018. The effect of each stressor, alone and in combination, was tested on the 2 groups of algae (4 treatments applied in triplicate), with the percent substratum covered by living coralline algae and the net primary production as response variables. Results showed that although some common trends were evident, different effects were observed for each morpho-functional group in relation to the considered response variable. These results highlight the importance of considering morpho-functional classification when predicting the response of coralline algae to disturbance and identifying their main threats.

A day in the life of winter plankton: under-ice community dynamics during 24 h in a eutrophic lake

Abstract Although diel vertical migration (DVM) in aquatic systems may account for the largest daily migration of biomass globally, our understanding of this process under ice cover is limited, particularly in fresh water. The date of lake ice onset and duration of ice cover is declining globally, therefore determining the extent of plankton migrations under ice is imperative to inform our baseline understanding of seasonal differences in community structure and function, and how conditions may change over time. We investigated whether plankton exhibit DVM under ice and explored interactions between phytoplankton and zooplankton at highly resolved space–time scales across 24 h in a eutrophic system. Despite the dominance of motile taxa, phytoplankton remained vertically segregated based on morpho-functional groups throughout the sampling period. Daphnia mendotae exhibited size-structured DVM with an upward migration at sunset and sunrise, and midnight sinking, presumably to avoid the rise of predatory Chaoborus. We hypothesize that because overwintering daphnids require rich lipid stores, D. mendotae migrated to access small, lipid-rich phytoplankton that were limited to surface waters. Given our study took place during an unusually warm winter in a eutrophic system, our results may represent future under-ice dynamics under increasing eutrophication pressure and climate warming in shallow lakes.

Macroalgae morpho-functional groups in Southern marine ecosystems: rocky intertidal in the Southwestern Atlantic (33°–35° S)

Macroalgae morpho-functional groups in Southern marine ecosystems: rocky intertidal in the Southwestern Atlantic (33°–35° S)

Impacts of a changing environment on marginal coral reefs in the Tropical Southwestern Atlantic

The peculiar shallow-water reefs of the Tropical Southwestern Atlantic Ocean have thrived in conditions considered suboptimal (e.g., moderate turbidity, higher level of nutrients, and resuspension of sediments) under the optics of classical coral reefs. Recently, these marginal reefs have been hypothesized to provide climate-change refugia from natural and anthropogenic impacts; yet with little empirical evidence. Therefore, in this article we discuss the known effects of multiple pressures on the Brazilian reefs. A wide evaluation of the peer reviewed literature reported that bleaching events affected 26 species of scleractinians, hydrocorals, octocorals, and zoanthids in turbid-zone reefs over the last 26 years (1994–2020) in the Tropical SW Atlantic Brazil. Between 1994 and 2018 no species suffered post-bleaching mass mortality. However, the recent and intense heatwaves of 2019 and 2020 caused higher mortality rates in several key foundation corals (e.g., Millepora alcicornis, Millepora braziliensis, and Mussismilia harttii) showing that the SW Atlantic reefs are not long-term protected and universal refuges. Moreover, other direct and indirect human pressures threaten these tropical reefs. Local and regional (e.g., pollution and fisheries) and large-scale pressures (e.g., global warming and marine heatwaves) act simultaneously on the health of these reefs, which intensifies negative species-specific impacts. We outline the occurrence of pressures that have been important factors responsible for the reduction in species richness and reef fish biomass, changing geo-ecological functions, altered reef composition and dominant morpho-functional groups, as well as phase shifts. Along with large-scale climatic changes, such as heatwaves, fisheries, urbanization, mining disasters, oil spills, increased sedimentation, increased warming, marine debris, contamination by domestic, agricultural, and industrial effluents, and introduction of invasive species are likely the most severe pressures on Brazilian reefs. We discuss that the “Brazilian reef refuge hypothesis” could be partially applied for some stress-tolerant massive corals during acute disturbances (short-term refuge); yet should not be assumed as a reef ecosystem-wide feature under ongoing environmental change. Therefore, we argue that it is essential to alleviate the main local and regional human impacts and to adopt resilient-based management strategies at local and global scales to protect the low-functional redundancy and higher endemism of these unique marginal coral reefs.

REDE ECOLÓGICA DOS GASTRÓPODES ASSOCIADOS AO BANCO DE ALGAS DA PRAIA DA RIBANCEIRA, SANTA CATARINA, BRASIL

Among the rocky shores’ biota, the networks of interaction between macroalgae and associated organisms, especially gastropods, stand out. In order to contribute to the understanding of the ecology of rocky shores, this study aims to evaluate the relation between macroalgae and associated gastropods in Ribanceira Beach, Imbituba, Santa Catarina, Brazil. The survey of algae samples took place in a wet season, using 20 cm x 20 cm quadrants, allocated in 18 transects distributed equally in the infra and mesolittoral zones, with five points each. In the laboratory, algae were screened and associated gastropods identified. Concepts of network theory were applied for a better understanding of interactions among organisms, where connectance descriptors, niche overlap and centrality index for each species were calculated. Multivariate techniques were used to assess the significance of intertidal zones, morphofunctional group and other variables in the composition of the associated gastropods. The sampling resulted in a total of 1.466 gastropods, distributed in 14 species and nine families. In relation to the macroalgae, 14 species were identified, with seven presenting associated gastropods. The ecological network showed low connectance and niche overlap for both levels (gastropods and macroalgae), suggesting the existence of many specific interactions. The centrality values highlighted Eulithidium affine (C.B. Adams, 1850) and Sargassum cymosum C. Agardh as key species in the studied network. The mass and morphofunctional group of the macroalgae sampled showed influence in the composition of the associated community. Cortical algae, especially S. cymosum, stood out with high levels of species richness and species density of associated gastropods, suggesting importance in the structural complexity of macroalgae for gastropods. The non-significant effect of the tidal zone for the gastropod composition was highlighted, suggesting that the nesting and foraging stability provided by the macroalgae allows the same gastropod species to occur in both infralittoral and mesolittoral zones.

Effect of land use on the phytoplankton community of Pampean shallow lakes of the Salado River basin (Buenos Aires Province, Argentina)

The Salado River basin, Buenos Aires, Argentina, contains numerous permanent shallow lakes under anthropic pressure due to different land uses/land covers (LULC) in their catchments. Here, we explored the relation of LULC in the surrounding areas and the physical and chemical variables of six shallow lakes of the aforementioned basin with phytoplankton structure and morpho-functional groups (MFGs) along one year and evaluated whether LULC or physical and chemical variables were more relevant in shaping phytoplankton structure. We hypothesized that: (1) shallow lakes with higher proportion of land committed to agriculture exhibit more eutrophic characteristics; (2) the phytoplankton structure and MFGs differ in shallow lakes with different LULC in their surrounding areas; and (3) LULC effects decrease with increase in buffer width. Landsat satellite images were used to extract LULC composition in three buffer zones surrounding each lake: 1, 2.5 and 5 km. In all the lakes studied, LULC had greater influence on phytoplankton MFGs than physical and chemical variables. This influence was highest for the 2.5 km buffer. The phytoplankton structure and some physical and chemical characteristics were also different between the shallow lakes studied. Cyanobacteria were widely detected, probably related to the high proportion of land dedicated to agriculture in the region. Chlorococcales, typical of these eutrophic systems, were also well represented. Our study evidenced the influence of LULC on the shallow lakes studied, particularly on the phytoplankton structure. The response of the planktonic microalgal communities to human activities in catchments evidences their value as sentinels of aquatic ecosystems.

基于功能类群分析呼兰河口湿地浮游植物群落结构特征

PDF HTML阅读 XML下载 导出引用 引用提醒 基于功能类群分析呼兰河口湿地浮游植物群落结构特征 DOI: 10.5846/stxb201911152444 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（31870187）；哈尔滨师范大学科研启动金项目（XKB201912）；哈尔滨师范大学高等教育教学改革研究项目，哈尔滨师范大学研究生教育教学改革项目 Analysis of phytoplankton structure based on different functional groups in Hulanhe Wetland Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:浮游植物对水环境条件变化敏感，其群落演替特征被广泛应用于指示水环境变化。基于3种浮游植物功能类群方法，对呼兰河口湿地浮游植物群落结构进行研究。于2018年春季（4、5月）、夏季（6、7、8月）和秋季（9、10月）三季，在呼兰河口湿地共设置11个采样点，通过ASNOSIM和SIMPER分析探索FG、MFG和MBFG功能类群的演替特征，基于RDA分析阐述功能类群对环境因子的响应模式。研究期间共鉴定浮游植物243个分类单位，隶属于7门9纲18目32科75属；其种类组成主要以绿藻门（46.09%）、裸藻门（19.34%）和硅藻门（18.52%）为主。共划分FG功能类群25个，MFG功能类群20个，MBFG功能类群6个；ANOSIM分析表明不同季节之间FG和MFG功能类群结构差异显著；SIMPER分析表明S1/Lo/W1/P/J/Y、9b/5a/11b/6a/2c/2d/1c和Ⅲ/Ⅰ类群是影响不同季节之间功能类群变化的主要类群；RDA分析表明，FG、MFG和MBFG功能类群的演替受多种环境因素共同影响，其中pH、BOD5、Tur.和CODMn与功能类群演替关系密切。相较于MBFG功能类群，FG和MFG功能类群能更好的响应呼兰河口湿地水环境的空间异质性。 Abstract:The Hulanhe Wetland is located in northeastern of China, and plays an important role in maintaining the biodiversity and regulating the microclimate in Harbin city. Although phytoplankton functional group studies on wetlands in northern China have increased recently, studies of the phytoplankton functional group in the Hulanhe Wetland are limited. To better understand processes of phytoplankton community succession in relation to environmental parameters, the functional mechanisms of biological communities may be better understood if species are pooled into groups with similar characteristics. Therefore, a detailed survey of three phytoplankton functional groups in spring, summer, and autumn are necessary. In this study, three different phytoplankton functional group methods were used to study phytoplankton community structure. Phytoplankton was qualitatively and quantitatively collected from 11 sampling sites in four typical habitats. The samples were collected in spring (April, May), summer (June, July, August), and autumn (September, October). A total of eleven sample sites were selected. We explored the succession characteristics of FG (Functional Group), MFG (Morpho-Functional Group) and MBFG (Morphology-Based Functional Group) functional groups by applying ASNOSIM and SIMPER analysis. A total of 243 phytoplankton species were identified, belonging to 7 phyla, 9 classes, 18 orders, 32 families and 75 genera. The phytoplankton species composition was dominated by and Chlorophyta (46.09%), followed by Euglenophyta (19.34%), Bacillariophyta (18.52%) and Cyanophyta (11.11%). During the study, the results showed that the average abundance of phytoplankton in the Hulanhe Wetland was significantly different (P<0.05). According to the abundance of phytoplankton, B (Cyclotella Kützing), J (Scenedesmus Meyen, Tetrastrum Chodat), D (Nitzschia Hassall), S1 (Pseudanabaena limnetica (Lemmermann) Komárek), Y (Cryptomonas erosa Hering, Cryptomonas ovata Hering) and W1 (Euglena Ehrenberg, Phacus Dujardin) were dominant in the functional groups. 25 functional groups, 20 Morpho-Functional Groups and 6 Morphology-based Functional Groups were identified during the study. The ANOSIM analysis showed significant differences in FG and MFG functional group structures between seasons. The SIMPER analysis indicated that the primary contributing phytoplankton functional groups were S1/Lo (Merismopedia Meyen)/W1/P (Melosira granulata (Ehrenberg) Ralfs)/J/Y, 9b (small unicells-Chlorococcales)/5a (thin fifilaments Oscillatoriales)/11b (Chlorococcales-Gelatinous colonies)/6a (large Centrics)/2c (small Euglenophytes)/2d (Cryptophytes)/1c (large Euglenophytes) and Ⅲ (large fifilaments)/Ⅰ (small organisms with high S/V). Redundancy Analysis (RDA) based on FG, MFG and MBFG and eleven environmental variables revealed that CODMn was the key factor driving the phytoplankton functional group succession, and Turbidity (Tur.), BOD5 and pH were closely related to phytoplankton functional group patterns. We found that MBFG approach was not as sensitive as FG and MFG approach in describing the variability of phytoplankton groups in the environment. We suggested that MBFG approach was not suitable for indicating the temperate wetland water environment condition. 参考文献 相似文献 引证文献

Dynamics of Morphofuncitonal Groups of Phytoplankton in the Rybinsk Resrevoir and Assessment of the Resevoir Water Quality by the Community Index

The changes in the ratio of species representing different morpho-functional groups, identified by physiological, morphological and ecological parameters [29] were analyzed based on the study on phytoplankton in different reaches of the Rybinsk Reservoir in 2000–2005. Water quality was assessed by the Q index of communities, developed taking into account the proportions of these groups. This assessment was compared with the evaluation using the values of Pantle–Buck saprobity index and phytoplankton biomass.

Semantic segmentation of major macroalgae in coastal environments using high-resolution ground imagery and deep learning

ABSTRACT Macroalgae are a fundamental component of coastal ecosystems and play a key role in shaping community structure and functioning. Macroalgae are currently threatened by diverse stressors, particularly climate change and invasive species, but they do not all respond in the same way to the stressors. Effective methods of collecting qualitative and quantitative information are essential to enable better, more efficient management of macroalgae. Acquisition of high-resolution images, in which macroalgae can be distinguished on the basis of their texture and colour, and the automated processing of these images are thus essential. Although ground images are useful, labelling is tedious. This study focuses on the semantic segmentation of five macroalgal species in high-resolution ground images taken in 0.5 × 0.5 m quadrats placed along an intertidal rocky shore at low tide. The target species, Bifurcaria bifurcata, Cystoseira tamariscifolia, Sargassum muticum, Sacchoriza polyschides and Codium spp., which predominate on intertidal shores, belong to different morpho-functional groups. An explanation of how to convert vector-labelled data to raster-labelled data for adaptation to Convolutional Neural Network (CNN) input is provided. Three CNNs (MobileNetV2, Resnet18, Xception) were compared, and ResNet18 yielded the highest accuracy (91.9%). The macroalgae were correctly segmented, and the main confusion occurred at the borders between different macroalgal species, a problem derived from labelling errors. In addition, the interior and exterior of the quadrats were correctly delimited by the CNNs. The results were obtained from only one hundred labelled images and the method can be performed on personal computers, without the need to use external servers. The proposed method helps automation of the labelling process.

Environmental risk analysis of pharmaceuticals on freshwater phytoplankton assemblage: effects on alpha, beta, and taxonomic diversity.

Antibiotics and nonsteroidal anti-inflammatory drugs (NSAIDs) have a wide range of bioactivities and are released into the ecosystem in large amounts. Heretofore, little information is available regarding their potential risk to the phytoplankton assemblage. Different alpha, taxonomic, and beta diversity measures were investigated and linked to the spatial variation of nine drugs. Distance-based redundancy analysis (dbRDA) indicated that pharmaceutical pollution had adverse effects on both phytoplankton diversity and taxonomic structure leading to the existence of congeneric taxa. However, different phytoplankton groups respond differently to different pharmaceuticals and Cyanoprokaryotes was suggested as the most sensitive group. According to the EC50 value and the detected concentration for each drug, a hazard index (Hq) was calculated for each polluted site to investigate environmental risk analysis. Increasing Hq values exhibited negative effects on phytoplankton diversity. Phytoplankton community was characterized by high beta diversity values, which suggested that microalgae were able to disperse and select suitable environmental conditions. High beta diversity values were driven by species difference rather than species replacement due to the disappearance of most sensitive taxa from highly polluted sites. Additionally, microalgae were classified into different morpho-functional groups (FGs), and principal component analysis (PCA) indicated that different FGs had different responses to pharmaceutical pollution. A laboratory toxicity experiment was also conducted to identify the negative effects of short-term exposure to low doses of paracetamol and ciprofloxacin.

Biodiversidad de algas epizoicas en el Pacífico tropical mexicano

Antecedentes y Objetivos: El conocimiento ficológico para la región del Pacífico mexicano es amplio, la mayoría de los estudios han estado orientados a conocer la flora adherida a sustratos rocosos. Sin embargo, es reducido el número de trabajos acerca de macroalgas que crecen sobre organismos vivos, como las algas epizoicas. El presente trabajo tiene como finalidad contribuir al conocimiento de la flora algal epizoica en el Pacífico tropical mexicano. Métodos: Se llevaron a cabo cuatro muestreos del molusco Chiton articulatus en dos localidades de Guerrero, México, durante 2014, para conocer las algas que crecen sobre él. Además, se realizó una revisión bibliográfica de estudios en el Pacífico tropical mexicano para obtener los registros de las algas que crecen sobre animales. Finalmente, se determinaron las algas en los moluscos mediante observaciones de talos completos y cortes. Resultados clave: En total se reportaron 124 especies, 81 géneros, 51 familias y 27 órdenes, distribuidos en cuatro divisiones de algas. Los órdenes con mayor riqueza específica fueron Ceramiales (23) y Corallinales (20) y las familias con mayor número de especies fueron Rhodomelaceae (13), Cladophoraceae (11) y Lithophyllaceae (10). Los géneros más diversos fueron Amphiroa y Cladophora (7). Se presentan, para Guerrero, 12 nuevos registros de especies, de los cuales tres son además nuevos registros para el Pacífico tropical mexicano y tres para el Pacífico de México. El estado con mayor número de especies registradas fue Guerrero (58). El sustrato más común fueron los moluscos. El grupo morfofuncional algal predominante fue los filamentos.Conclusiones: Los resultados de este trabajo demuestran que la biodiversidad de algas presente en los sustratos animales es alta, y contribuye notablemente a la riqueza específica registrada para Guerrero y para el Pacífico de México. Se hace patente la importancia de desarrollar más estudios que se enfoquen al conocimiento de la epibiosis algal.