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1.
Sci Total Environ ; 700: 134392, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31704513

RESUMO

Estuaries worldwide are undergoing changes to patterns of aquatic productivity because of human activities that alter flow, impact sediment delivery and thus the light field, and contribute nutrients and contaminants like pesticides and metals. These changes can influence phytoplankton communities, which in turn can alter estuarine food webs. We used multiple approaches-including high-resolution water quality mapping, synoptic sampling, productivity and nitrogen uptake rates, Lagrangian parcel tracking, enclosure experiments and bottle incubations-over a short time period to take a "spatial snapshot" of conditions in the northern region of the San Francisco Estuary (California, USA) to examine how environmental drivers like light availability, nutrients, water residence time, and contaminants affect phytoplankton abundance and community attributes like size distribution, taxonomic structure, and nutrient uptake rates. Zones characterized by longer residence time (15-60 days) had higher chlorophyll-a concentrations (9 ±â€¯4 µg L-1) and were comprised primarily of small phytoplankton cells (<5 µm, 74 ±â€¯8%), lower ammonium concentrations (1 ±â€¯0.8 µM), higher nitrate uptake rates, and higher rates of potential carbon productivity. Conversely, zones characterized by shorter residence time (1-14 days) had higher ammonium concentration (13 ±â€¯5 µM) and lower chlorophyll-a concentration (5 ±â€¯1 µg L-1) with diatoms making up a larger percent contribution. Longer residence time, however, did not result in the accumulation of large (>5 µm) cells considered important to pelagic food webs. Rather, longer residence time zones had a phytoplankton community comprised primarily of small cells, particularly picocyanobacteria that made up 38 ±â€¯17% of the chlorophyll-a - nearly double the concentration seen in shorter residence time zones (22 ±â€¯7% picocyanobacterial of chlorophyll-a). Our results suggest that water residence time in estuaries may have an effect as large or larger than that experimentally demonstrated for light, contaminants, or nutrients.


Assuntos
Ecossistema , Cadeia Alimentar , Fitoplâncton/crescimento & desenvolvimento , Compostos de Amônio , Clorofila A , Diatomáceas , Monitoramento Ambiental , Estuários , Água Doce , Nitrogênio/análise , São Francisco , Qualidade da Água
2.
J Environ Sci (China) ; 86: 38-49, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31787189

RESUMO

Three fractions of alkaline phosphatase activity (APA), including phytoplankton APA (phyto-APA), bacterial APA (bact-APA), and free-APA, were examined in the sea surface microlayer (SML) and the subsurface water (SSW) from Daya Bay, Guishan Island, and Guanghai Bay of southern China. Relationships between APA and environmental parameters were analyzed. The growth of phytoplankton was significantly limited by dissolved inorganic phosphorus (DIP) in the three sea areas, especially in Daya Bay. Total-APA ranged between 1.41 and 35.26 nmol/L/hr, and the highest value was found in Daya Bay. The increased APA in Daya Bay was the result of the increase of phytoplankton biomass and the response of phytoplankton to P limitation. Phyto-APA was the main contributor in Daya Bay, while phyto- and free-APA co-dominated in Guishan Island and Guanghai Bay. Bact-, phyto-, and total-APA showed a significant inverse power function relationship with DIP, and 0.2 µmol/L was the threshold for DIP on particulates and total-APA. Pearson correlation analysis suggested that DIP limitation together with high N levels enhanced APA. High water temperature and freshwater input accelerated APA as well. Principal component analysis clearly separated samples from the three sea areas, as well as from the SML and the SSW, which indicated the differences in environmental parameters and APA levels. Our results highlight the influence of phosphorus limitation and environmental parameters on APA.


Assuntos
Fosfatase Alcalina/análise , Monitoramento Ambiental , Fósforo/análise , Fitoplâncton/crescimento & desenvolvimento , Biomassa , China
3.
Environ Monit Assess ; 191(11): 688, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31664528

RESUMO

Understanding the relative impact sizes of environmental factors and nutrients on the high annual variation of phytoplankton abundance in eutrophic rivers is important for aquatic ecosystem management efforts. In this study, we used phytoplankton dynamic datasets in the eutrophic Fenhe River to show the variations and drivers of phytoplankton abundance under complex, fluctuating environmental conditions during 2012-2017. The temporal and spatial variations of nutrients in the river depicted that the total phosphorus (TP) concentration was higher in the wet season and in downstream. There were increases in total nitrogen (TN) concentration in the normal season and in upstream. The structural equation model (SEM) showed that the phytoplankton abundance increased during the wet season despite the decrease in the TN:TP ratio and was reduced upstream due to the highest TN:TP ratio. Among the environmental variables, water temperature (WT) was an important predictor and positively correlated temporally and spatially to phytoplankton. The interaction of nutrients with the phytoplankton community at different temperature levels indicated that different phytoplankton groups have different nutrient requirements. We can conclude that enhances in temperature and TP concentration will significantly increase phytoplankton abundance and dominance of cyanobacteria and green algae in the future, whereas there was insignificant effect on diatoms. These data indicated that temperature and TP content were the important abiotic factors influencing the phytoplankton growth of the water body, which could provide a reference for the evaluation of environmental alterations in the future.


Assuntos
Monitoramento Ambiental , Fitoplâncton/crescimento & desenvolvimento , Temperatura Ambiente , Poluentes da Água/análise , China , Clorófitas , Cianobactérias/crescimento & desenvolvimento , Diatomáceas/crescimento & desenvolvimento , Ecossistema , Eutrofização , Nitrogênio/análise , Nutrientes , Fósforo/análise , Rios/química , Estações do Ano
4.
Mar Pollut Bull ; 145: 105-117, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31590766

RESUMO

The Beagle Channel is a remote subantarctic environment where mussel aquaculture initiatives have existed since the early 1990s. Here we analyze phytoplankton biomass and composition, and the occurrence of harmful microalgae species and their toxins at three sites during the period 2015-2016. The occurrence of potentially harmful algae was observed throughout the study period, including toxigenic dinoflagellates such as Alexandrium catenella (Group I of the A. tamarense complex), A. ostenfeldii, Dinophysis acuminata, Gonyaulax spinifera, Azadinium sp., and the diatoms Pseudo-nitzschia australis and P. fraudulenta. Toxic dinoflagellates were detected in low densities whereas a Pseudo-nitzschia bloom was observed in late February. Isolates of A. catenella and P. delicatissima sensu stricto were phylogenetically characterized. The toxin profile of A. catenella was dominated by GTX4, while P. delicatissima sensu stricto showed no production of the neurotoxin domoic acid in culture conditions. The results provide base-line information for the management of harmful algal blooms in this little explored subantarctic area.


Assuntos
Aquicultura , Diatomáceas/química , Dinoflagelados/química , Toxinas Marinhas/análise , Fitoplâncton/química , Animais , Biomassa , Diatomáceas/classificação , Diatomáceas/crescimento & desenvolvimento , Dinoflagelados/classificação , Dinoflagelados/crescimento & desenvolvimento , Proliferação Nociva de Algas , Microalgas/química , Microalgas/classificação , Microalgas/crescimento & desenvolvimento , Fitoplâncton/classificação , Fitoplâncton/crescimento & desenvolvimento , América do Sul
5.
Science ; 365(6457): 1040-1044, 2019 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-31488692

RESUMO

From June to August 2018, the eruption of Kilauea volcano on the island of Hawai'i injected millions of cubic meters of molten lava into the nutrient-poor waters of the North Pacific Subtropical Gyre. The lava-impacted seawater was characterized by high concentrations of metals and nutrients that stimulated phytoplankton growth, resulting in an extensive plume of chlorophyll a that was detectable by satellite. Chemical and molecular evidence revealed that this biological response hinged on unexpectedly high concentrations of nitrate, despite the negligible quantities of nitrogen in basaltic lava. We hypothesize that the high nitrate was caused by buoyant plumes of nutrient-rich deep waters created by the substantial input of lava into the ocean. This large-scale ocean fertilization was therefore a unique perturbation event that revealed how marine ecosystems respond to exogenous inputs of nutrients.


Assuntos
Fitoplâncton/crescimento & desenvolvimento , Água do Mar/química , Erupções Vulcânicas , Clorofila A/análise , Clorofila A/metabolismo , Eutrofização , Hawaii , Metais/análise , Nitratos/análise , Nitrogênio/análise , Oceano Pacífico , Fitoplâncton/metabolismo , Água do Mar/análise
6.
Sci Total Environ ; 694: 133721, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31400686

RESUMO

The use of short-term, fast-acting curative treatments to rapidly suppress the proliferation of upcoming cyanobacterial blooms without negative side effects on overall water quality is important for environmental regulatory agencies. A 15-day in situ mesocosm experiment was conducted to evaluate the effects of algal harvest at different intensities and the effect of hydrogen peroxide on the mitigation of cyanobacterial blooms, subsequent algal growth and phytoplankton community structure. The results indicate that filtration through a 30-µm-pore-size net could remove most of the Microcystis colonies, leading to a decline in algal biomass. However, algal harvest at 30% and 60% intensities tended to promote cyanobacterial growth under nutrient-replete conditions, and the mitigation effect only lasted a few days, since cyanobacteria biomass exhibited no significant difference between the control and those two treatments on Day 6. When the algal harvest intensity was 90%, the cyanobacterial biomass remained at a relatively low level for 15 days. The average Microcystis colony size rapidly returned to the initial level after an initial decline across all the algal harvest intensities, indicating that algal harvest should be repeatedly performed within a short time period to mitigate Microcystis blooms. Furthermore, removing Microcystis colonies by filtration led to increased diversity in the phytoplankton community, as the proportion of non-Microcystis cyanobacteria increased with harvest intensity. This result might pose a challenge for cyanobacterial bloom control over the long term if filamentous cyanobacteria become dominant. The 10.0 mg L-1 H2O2 treatment selectively suppressed cyanobacteria throughout the experimental period, leading to succession from a cyanobacteria-dominated to a Chlorophyta-dominated community after Day 9. Overall, using hydrogen peroxide is more effective than algal harvesting as a one-time quick curative measure.


Assuntos
Cianobactérias/crescimento & desenvolvimento , Recuperação e Remediação Ambiental/métodos , Proliferação Nociva de Algas , Peróxido de Hidrogênio , Monitoramento Ambiental , Microalgas , Microcistinas , Microcystis , Fitoplâncton/crescimento & desenvolvimento
7.
Sci Total Environ ; 694: 133396, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31401512

RESUMO

The Arabian Sea is prone to large-scale algal blooms during winter monsoon annually. However, it is unclear why dinoflagellate, especially Noctiluca scintillans, replaced diatoms as the main bloom species. Based on in situ, remote sensing and numerical-model data off Pakistan, we found a stratified water with less salty, suitable temperature (~24 °C) and low-light conditions at the subsurface, as well as the organic nutrient accumulation and silicate limitation, were crucial for the growth of N. scintillans and outcompeting diatoms. The superposition of cyclonic eddy promoted N. scintillans pumping to surface and forming large-scale bloom. Subsequently, the shading effect of surface bloom caused the disappearance of subsurface chlorophyll maximum layer. This result suggests that the combined effects of nutrient structure and hydrodynamics play an important role in the prevalence of N. scintillans.


Assuntos
Diatomáceas/crescimento & desenvolvimento , Dinoflagelados/crescimento & desenvolvimento , Monitoramento Ambiental , Eutrofização , Paquistão , Fitoplâncton/crescimento & desenvolvimento , Estações do Ano , Água do Mar , Temperatura Ambiente
8.
Mar Pollut Bull ; 148: 30-46, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31422301

RESUMO

Monthly measurements of nitrate, nitrite, ammonium and phosphate at three stations off Kuwait during 2002-2015 revealed considerable inter-annual variability, broadly corresponding to fluctuations in the Shatt-al-Arab River discharge, but a lack of secular increasing trend. Nutrient enrichment experiments during two seasons revealed nitrate uptake, chlorophyll build-up and growth of micro-phytoplankton, even in the presence of ammonium, provided the availability of phosphate. Primary production was mostly nitrogen limited, but anthropogenic nitrogen supply may eventually make it phosphorus limited, especially in summer and in the open Gulf. Anthropogenic nutrient inputs appear to have enhanced biological productivity of the northern Gulf, but heterotrophic consumption, indicated by high respiration rates, probably prevented accumulation of phytoplankton biomass, accounting for the observed lack of chlorophyll increase over the past three decades. Consequently high total organic carbon and emerging hypoxia in the Gulf may lead to expansion/intensification of the oxygen minimum zone of the Arabian Sea.


Assuntos
Nutrientes/análise , Fitoplâncton/metabolismo , Água do Mar/química , Biomassa , Clorofila/metabolismo , Oceano Índico , Kuweit , Oxigênio/análise , Fitoplâncton/crescimento & desenvolvimento , Rios/química , Estações do Ano , Água do Mar/microbiologia
9.
Sensors (Basel) ; 19(15)2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31366087

RESUMO

The baseline of a specific variable defines the average behavior of that variable and it must be built from long data series that represent its spatial and temporal variability. In coastal and marine waters, phytoplankton can produce blooms characterized by a wide range of total cells number or chlorophyll a concentration. Classifying a phytoplankton abundance increase as a bloom depends on the species, the study area and the season. The objective of this study was to define the baseline of satellite absorption coefficients in Todos Santos Bay (Baja California, Mexico) to determine the presence of phytoplankton blooms based on the satellite inherent optical properties index (satellite IOP index). Two field points were selected according to historical bloom reports. To build the baseline, the data of phytoplankton absorption coefficients ( a p h y , G I O P ) and detritus plus colored dissolved organic matter (CDOM) ( a d C D O M , G I O P ) from the generalized inherent optical property (GIOP) satellite model of the NASA moderate resolution imaging spectroradiometer (MODIS-Aqua) sensor was studied for the period 2003 to 2016. Field data taken during a phytoplankton bloom event on June 2017 was used to validate the use of satellite products. The association between field and satellite data had a significant positive correlation. The satellite baseline detected a trend change from high values to low values of the satellite IOP index since 2010. Improved wastewater treatment to waters discharged into the Bay, and increased aquaculture of filter-feeding mollusks could have been the cause. The methodology proposed in this study can be a supplementary tool for permanent in situ monitoring programs. This methodology offers several advantages: A complete spatial coverage of the specific coastal area under study, appropriate temporal resolution and a tool for building an objective baseline to detect deviation from average conditions during phytoplankton bloom events.


Assuntos
Técnicas Biossensoriais , Diatomáceas/crescimento & desenvolvimento , Monitoramento Ambiental/métodos , Fitoplâncton/crescimento & desenvolvimento , Clorofila/análise , Eutrofização , Estações do Ano
10.
Artigo em Inglês | MEDLINE | ID: mdl-31349664

RESUMO

The available observations for the model are usually sparse and uneven. The application of interpolation methods help researchers obtain an approximate form of the original data. A marine nutrient, phytoplankton, zooplankton and detritus (NPZD) type ecosystem model is applied to simulate the distribution of phytoplankton combined with the spline interpolation (SI) and the Cressman interpolation (CI). In the idealized twin experiments, the performance of these two interpolation methods is validated through the analysis of several quantitative metrics, which show the minor error and high efficiency when using the SI. Namely, the given distributions can be better inverted with the SI. The actual distribution of phytoplankton in the Bohai Sea is interpolated in the practical experiment, where a satisfactory simulation result is obtained by the model with the SI. The model experiments and results verify the feasibility and effectiveness of SI.


Assuntos
Biodiversidade , Ecossistema , Fitoplâncton/crescimento & desenvolvimento , Zooplâncton/crescimento & desenvolvimento , Animais , Modelos Teóricos
11.
Environ Sci Pollut Res Int ; 26(25): 25445-25451, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31264150

RESUMO

The effect of polystyrene (PS) particles on the toxicity of triphenyltin (TPT) to the marine diatom Skeletonema costatum was investigated. The 0.1-µm PS particles attached to the cell walls of S. costatum but did not cause adverse effects on the growth of the diatom. The adsorption of TPT to PS particles was negligible in seawater systems, but the presence of 0.1-µm PS significantly reduced the bioavailable concentrations of TPT in f/2-Si medium, indicating a potential three-way interaction between TPT, PS particles, and components of f/2-Si medium. The adsorption of TPT to PS of smaller size (i.e., 0.1 µm) was stronger than that of PS of larger size (i.e., 5 µm), which was probably attributed to larger surface areas of smaller PS particles. The presence of PS could reduce the toxicity of TPT. IC50 values of TPT increased from 0.56 to 0.85 and 0.71 µg/L at the presence of 20 mg/L 0.1-µm PS and 5-µm PS, respectively. The overall results of this study profiled the combined toxic effects of PS and TPT on marine phytoplankton species and highlighted the difference in adsorption of organic pollutants by microplastics in different ambient mediums.


Assuntos
Diatomáceas/efeitos dos fármacos , Compostos Orgânicos de Estanho/química , Fitoplâncton/crescimento & desenvolvimento , Plásticos/metabolismo , Poliestirenos/metabolismo , Adsorção , Tamanho da Partícula , Poliestirenos/química , Água do Mar
12.
Environ Monit Assess ; 191(8): 485, 2019 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-31280379

RESUMO

The limited carrying capacities of shallow tropical lakes render them more vulnerable to ecological problems like eutrophication. Unregulated human activities such as unsustainable aquaculture and urbanization can alter ecosystem dynamics rapidly, and this warrants more comprehensive researches than what has been previously conducted. Here, we presented an integrated assessment of the nutrient dynamics, phytoplankton diversity, and sediment geochemistry in Lake Palakpakin, a shallow tropical lake of volcanic origin, to understand its deteriorating ecological state. Water, phytoplankton, and sediment samples were collected, and in situ water quality measurements were done during wet and dry seasons in four critical areas in the lake, namely, the inlet, center, sanctuary, and outlet. Results revealed that high light extinction coefficient (1.13 m-1), high turbidity (28 NTU), high phosphate concentration (> 2.0.5 mg/L), and the abundance of Microcystis aeruginosa, Anabaena helicoidea, and Lyngbya sp. indicate that from a relatively healthy lake in 2008, Lake Palakpakin has become a eutrophic to hypereutrophic freshwater body. High concentrations of available nutrients such as N and P were detected in the center and sanctuary sediments, which drive the internal nutrient loading in the lake. We recommend that management efforts be directed towards a whole-ecosystem approach in addressing the problem of eutrophication, especially in shallow tropical lakes.


Assuntos
Monitoramento Ambiental , Lagos/química , Fitoplâncton/crescimento & desenvolvimento , Biodiversidade , Conservação dos Recursos Naturais , Cianobactérias , Ecossistema , Eutrofização , Sedimentos Geológicos/química , Microcystis , Filipinas , Fósforo/análise , Estações do Ano , Poluentes da Água/análise , Qualidade da Água
13.
Chemosphere ; 234: 34-42, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31203039

RESUMO

Due to excessive loadings of nitrogen (N) and phosphorus (P), frequent blooms of harmful cyanobacteria and their associated cyanotoxins pose serious threats to recreational usage and human health. However, whether cyanobacteria growth and toxin production are limited by N, P, or both N + P is still not clear. Thus, we conducted a nutrient enrichment bioassay in situ in Spring Lake, a eutrophic lake in west Michigan, USA, to examine the influence of nutrient limitation on the proliferation of algal blooms and the production of microcystins (MC). N or P addition alone resulted in a slight increase in the concentration of chlorophyll-a (Chl-a), suggesting a positive effect on phytoplankton growth, but alone, neither were sufficient to induce algal blooms. In contrast, the combination of N and P had a significant and positive influence on phytoplankton growth and MC production. Compared to controls, the N + P treatment resulted in high concentrations of Chl-a and MC, as well as high pH and dissolved oxygen. In addition, significant increases were observed in different MC analogues for each treatment; the highest concentrations of intracellular MC-LR, -RR, -YR, and TMC (total MC) were found in the N + P treatment with values of 9.16, 6.10, 2.57, and 17.82 µg/L, respectively. This study suggests that at least in this temperate coastal lake, cyanobacterial blooms and associated MC are influenced more by combined N and P enrichment than by N or P alone, indicating that managing both nutrients is important for effectively reducing algal blooms and MC production.


Assuntos
Lagos/microbiologia , Microcistinas/metabolismo , Nitrogênio/farmacologia , Nutrientes/farmacologia , Fósforo/farmacologia , Fitoplâncton/crescimento & desenvolvimento , Carcinógenos/metabolismo , Eutrofização , Lagos/análise , Fitoplâncton/efeitos dos fármacos
14.
Sci Total Environ ; 683: 822-833, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31154160

RESUMO

Fungal communities in the coastal waters have long been known to be dynamic with a significant role in organic matter cycling. However, the effects of environmental gradients on their community structures are poorly described. Here we studied three coastal sites off the South China Sea, namely Pearl River Estuary (PE), Shenzhen Bay (SB), and Daya Bay (DB) with contrasting trophic status and heterogenous local influences. Environmental analysis of these sites suggested higher nutrient and low salinity levels at PE and SB with wide variability compared to DB. Average molecular abundances (18S rRNA gene copy numbers) at sites PE (1.05 ±â€¯0.27 × 107 copies L-1) and SB (1.2 ±â€¯0.69 × 107 copies L-1) were similar and significantly higher (P < 0.05) than that at site DB (5.5 ±â€¯9.5 × 105 copies L-1). Although planktonic fungi were molecularly abundant at the three sites, live fungal biomass based on ergosterol assay was detected only at some stations of PE and SB. Both molecular abundance and live biomass were significantly correlated with chemical oxygen demand, nutrients, and phytoplankton biomass, supporting their role in detritus turnover. The fungal communities were unprecedently diverse with the ubiquitous dominance of Dikarya and the occasional predominance of Glomeromycota, Mucoromycota, Mortierellomycota, and Chytridiomycota. A total of 24 classes, 46 orders, 71 families, 59 genera, and eight species were classified within the eight detected phyla, including the new finding of ascomycetous class Geoglossomycetes in coastal waters. Salinity and nitrate were the significant (r2 = 0.70, P < 0.05) factors that determined the ß-diversity of fungal communities. Overall, this study suggests that although planktonic fungi are ubiquitous in coastal habitats, their molecular abundances and diversities (both α and ß) are significantly determined by environmental gradients, particularly the salinity, COD and nitrate levels of coastal waters.


Assuntos
Ecossistema , Monitoramento Ambiental , Fungos/crescimento & desenvolvimento , Fitoplâncton/crescimento & desenvolvimento , Microbiologia da Água , Biodiversidade , China , Cadeia Alimentar
15.
Mar Pollut Bull ; 142: 119-128, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31232284

RESUMO

To explore the effects of coastal eutrophication and warming on phytoplankton biomass and cell size, we analyzed current and historical data for size-fractionated chlorophyll a (chla) in Xiangshan Bay, China. Results showed that micro- and nanophytoplankton overwhelmingly dominated (>84%) in all seasons. The contribution of micro-chla was significantly lower in warm than in cold seasons, whereas contribution of pico-chla showed the opposite result. Overall, the micro-chla contribution increased with decreasing pico-chla contribution from the stable, clear, eutrophic upper bay to the turbulent, turbid lower bay, indicating that phytoplankton size structure on a spatial scale was largely shaped by water column stability and light rather than by nutrients. Since the 1980s, phytoplankton biomass, primary productivity, and micro-chla contribution in Xiangshan Bay have increased sharply with increasing nutrient amounts and temperature. Additionally, it seems that algal bloom seasonality has shifted forward from spring to winter since the power plant operations in 2006.


Assuntos
Fitoplâncton , Baías , Biomassa , China , Clorofila A/análise , Eutrofização , Fitoplâncton/citologia , Fitoplâncton/crescimento & desenvolvimento , Centrais Elétricas , Estações do Ano , Análise Espaço-Temporal , Temperatura Ambiente
16.
Environ Sci Pollut Res Int ; 26(19): 19575-19587, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31079295

RESUMO

Long-term cyanobacterial blooms and hypereutrophic state have been typical for the shallow, urban Swarzedzkie Lake for many years. Diversion of sewage did not change its trophic status, so restoration began in autumn 2011 using the sustainable approach based on three methods. The aim of the study was to analyse how sustainable restoration affects zooplankton. We hypothesised that bottom-up and top-down methods reconstructed zooplankton composition. Thus, the abundance of large-size cladocerans increased and controlled phytoplankton effectively. The elimination of cyanobacteria bloom, the decrease of rotifer abundance and the twofold increase of filter-feeder effectiveness were observed in summer 2012. However, high phosphorus concentration, lack of regular cyprinid removal and insufficient fish stocking together with high temperature prevented zooplankton from controlling cyanobacteria bloom in summer 2013. Rotifer domination with high trophy species was noted, as before restoration. The number of rotifers decreased in 2014, while crustaceans increased due to the significant decrease of nutrient concentrations and an intensification of biomanipulation treatments. Therefore, summer phytoplankton growth was low, without cyanobacteria dominance. The rebuilding of zooplankton in Swarzedzkie Lake was observed during sustainable restoration. However, the treatments should be intensified when adverse changes were observed to obtain better results for the improvement of water quality.


Assuntos
Recuperação e Remediação Ambiental/métodos , Eutrofização , Lagos/química , Modelos Teóricos , Qualidade da Água , Zooplâncton/crescimento & desenvolvimento , Animais , Cianobactérias/crescimento & desenvolvimento , Peixes , Fósforo/análise , Fitoplâncton/crescimento & desenvolvimento , Polônia , Estações do Ano
17.
Extremophiles ; 23(4): 467-477, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31087168

RESUMO

In April 2014, dual bloom of green algae and purple bacteria occurred in a shallow, alkaline soda pan (Kiskunság National Park, Hungary). The water was only 5 cm deep, in which an upper green layer was clearly separated from a near-sediment purple one. Based on microscopy and DNA-based identification, the upper was inhabited by a dense population of the planktonic green alga, Oocystis submarina Lagerheim, while the deeper layer was formed by purple, bacteriochlorophyll-containing bacteria, predominated by Thiorhodospira and Rhodobaca. Additional bacterial taxa with a presumed capability of anoxygenic phototrophic growth belonged to the genera Loktanella and Porphyrobacter. Comparing the bacterial community of the purple layer with a former blooming event in a nearby soda pan, similar functional but different taxonomic composition was revealed. Members from many dominant bacterial groups were successfully cultivated including potentially new species, which could be the result of the application of newly designed media.


Assuntos
Clorófitas/crescimento & desenvolvimento , Eutrofização , Lagos/microbiologia , Microbiota , Proteobactérias/crescimento & desenvolvimento , Biomassa , Fitoplâncton/crescimento & desenvolvimento
18.
Environ Monit Assess ; 191(6): 382, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31111231

RESUMO

At present, there are few studies on the quantitative analysis of connectivity from the perspective of biocenology. This study aimed to develop a new quantitative assessment method for river connectivity based on the analysis of the effect of river connectivity on the phytoplankton community in the Shaying River, which has multiple gates. The results showed that from the view of the phytoplankton density and biomass, cryptophytes were the dominant phytoplankton group, but the cyanobacteria density was highest in the summer. In the top 10 of degrees of dominance, there were 4 species of cyanobacteria, 3 species of cryptophytes, 2 species of diatoms, and 1 species of chlorophytes. Based on the seasonal compositions and variations of the phytoplankton community, the river barriers had a great effect on the community. The community composition of the Shaying River has been transformed from a river-type community dominated by diatoms to a lake-type community dominated by cyanophytes. PCA (principal component analysis) indicated that there were obvious differences in the community structure among the sections partitioned by various river gates. According to the relative positions of the entire phytoplankton community and the relative sequence of the river gates, a potential gradient representing the river connectivity can be found; thus, the river connectivity can be quantitatively described from the perspective of the phytoplankton community, and hereby, the corresponding quantitative methods can be established. Characterizing the connectivity of rivers based on biota will facilitate assessing the effects of multiple barriers and understanding river connectivity, and provide the support for the effective management of rivers.


Assuntos
Conservação dos Recursos Hídricos/métodos , Monitoramento Ambiental/métodos , Fitoplâncton/crescimento & desenvolvimento , Rios/química , Movimentos da Água , Biomassa , Biota , Cianobactérias/crescimento & desenvolvimento , Diatomáceas/crescimento & desenvolvimento , Lagos/química , Análise de Componente Principal , Estações do Ano
19.
Ecotoxicology ; 28(5): 559-568, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31123966

RESUMO

Previous field investigations implied a potential phosphorus (P)-limitation on the growth of phytoplankton in Daya Bay, a mesotrophic bay in the northern South China Sea. Using a total of 15 mesocosms (3 × 3 × 1.5 m, with ~10.8 m3 natural seawater containing phytoplankton assemblages for each), we found P-enrichment caused no obvious effect on phytoplankton (Chl a) growth across 8-day's cultivation in neither winter nor summer, while nitrogen (N)-enrichment greatly increased Chl a in both seasons. N plus P-enrichment further increased Chl a content. The N- or N plus P-enrichments increased the allocation of nano-Chl a but decreased micro-Chl a in most cases, with no obvious effect by P-alone. Coincided with nutrients effect on Chl a content, N- or N plus P-enrichments significantly enhanced the maximum photochemical quantum yield of Photosystem II (FV/FM) and maximum relative electron transport rate (rETRmax), but declined the non-photochemical quenching (NPQ), as well as the threshold for light saturation of electron transport (EK); again, P-enrichment had no significant effect. Moreover, the absorption cross section for PSII photochemistry (σPSII) and electron transport efficiency (α) increased due to N- or N plus P-enrichments, indicating the increased nutrients enhance the light utilization efficiency through promoting PSII light harvesting ability, and thus to enhance phytoplankton growth. Our findings indicate that N- or N plus P-enrichments rigorously fuel phytoplankton blooms regardless of N:P ratios, making a note of caution on the expected P-deficiency or P-limitation on the basis of Redfield N:P ratios in Daya Bay.


Assuntos
Monitoramento Ambiental , Fósforo/metabolismo , Fitoplâncton/crescimento & desenvolvimento , Poluentes Químicos da Água/metabolismo , Baías , China , Eutrofização , Nutrientes/metabolismo , Fitoplâncton/efeitos dos fármacos
20.
Huan Jing Ke Xue ; 40(5): 2249-2257, 2019 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-31087863

RESUMO

Yilong Lake, a shallow, plateau lake, is the ninth largest water body in the Yunnan Province, China. In order to figure out the characteristics of phytoplankton communities in different regions of this lake, the phytoplankton and environmental factors in the west region, east region, and in a submerged macrophytes restoration demonstration region were monthly investigated and analyzed from August 2013 to July 2014. The results showed that the habitats in different regions were spatially heterogeneous. Total nitrogen (TN), total phosphorus (TP), ammonia nitrogen (NH4+-N), five-day biochemical oxygen demand (BOD5), transparency (SD), turbidity (Turb.), and electrical conductivity (EC) had no significant differences between the demonstration region and the west region, but these two regions showed significant differences in comparison with the east region (P<0.05). The largest phytoplankton density was Cyanophyta and the dominant species in the three regions were different. Mersmopedia tenuissima had the highest dominance in the west region; Cylindrospermopsis raciborskii and Pseudanabaena limntica were the most dominant taxa in the east region; while Merismopedia tenuissima and Anabaenopsis sp. were dominant in the O. uminata restoration demonstration region. PCoA compared the ß diversity of phytoplankton communities in the three different regions based on the entire year investigations. It was found that the community structures of the west region and O. uminata restoration demonstration region were similar (P>0.05), but they were significantly different from the community from the east region (P<0.01). Redundant analysis (RDA) showed that TN, TP, BOD5, and SD were the main environmental factors affecting the distribution of phytoplankton community in Yilong Lake. In addition, NH4+-N, EC, permanganate index, and pH also have a certain effect on the phytoplankton community.


Assuntos
Lagos , Fitoplâncton/classificação , Fitoplâncton/crescimento & desenvolvimento , Análise da Demanda Biológica de Oxigênio , China , Monitoramento Ambiental , Nitrogênio/análise , Fósforo/análise , Qualidade da Água
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