scholarly journals Snow algae blooms are beneficial for microinvertebrates assemblages (Tardigrada and Rotifera) on seasonal snow patches in Japan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masato Ono ◽  
Nozomu Takeuchi ◽  
Krzysztof Zawierucha
Keyword(s):  
Low Temperature ◽  
Algal Blooms ◽  
Sampling Site ◽  
High Biomass ◽  
Population Densities ◽  
Snow Algae ◽  
Seasonal Snow ◽  
Algae Blooms ◽  
Surface Snow ◽  
Northern Japan

AbstractAlthough studies on snow algae and macroinvertebrates have been frequently conducted on snow patches, only few surveys have been focused on microinvertebrates which reach high biomass and play various trophic roles in other cold habitats. The aims of this study were (1) to search for microinvertebrates in seasonal surface snow patches located on the slope of Mt. Gassan, in northern Japan, and (2) to identify factors determining their distribution associated with snow algal blooms of various colorations (orange, green, and golden-brown) collected from the same sampling site over two seasons (2018, 2019). Microscopic observation revealed presence of two major groups of microinvertebrates: Tardigrada and Rotifera. They were concentrated in green snow colored by blooms of Chloromonas sp. in comparison to orange or golden-brown snow and only a few were found in white snow. Mean body length of tardigrades increased throughout the melt season, their intestine content was green and they laid eggs on colored snow. These results suggest that tardigrades preferentially grew and reproduced on green snow patches. Population densities of tardigrades, rotifers and concentration of chlorophyll a were significantly correlated. Our study indicates that green snow patches in temperate mountainous forests constitute important and unique low-temperature ecosystems for microinvertebrates. Snow covered by algae is an unrecognized novel habitats for tardigrades and rotifers.

scholarly journals Snow Algae Blooming Are Benefitable for Microinvertebrates Assemblages (Tardigrada and Rotifera) on the Seasonal Snow Patches in Japan

2020 ◽  
Author(s):  
Masato Ono ◽  
Nozomu Takeuchi ◽  
Krzysztof Zawierucha
Keyword(s):  
Low Temperature ◽  
Body Length ◽  
Microscopic Observation ◽  
Forest Area ◽  
High Biomass ◽  
Snow Algae ◽  
Seasonal Snow ◽  
Novel Habitat ◽  
Melting Season ◽  
Northern Japan

Abstract Although studies on snow algae and macroinvertebrates have been frequently conducted on snow patches, no attention have been paid to ubiquitous microinvertebrates which in other cold habitats reach high biomass and play various trophic roles. The aim of this study was to search microinvertebrates in seasonal snow patches in Mt. Gassan, in northern Japan, and identify factors determining their distribution associated with snow algal blooming of various coloration (red, green, and yellow). Microscopic observation revealed presence of two major groups of microinvertebrates Tardigrada and Rotifera. Tardigrades and rotifers were the most abundant and frequent in green snow formed by blooming of Chloromonas sp., but few in red or yellow snow. Body length of tardigrades increased through the melting season and animals laid eggs on colored snow. These results suggest tardigrades successfully grew and reproduced on snow patches. Taking into account the presence of tardigrades and rotifers mostly in green snow (only few found in red and yellow) with high densities, we may assume green snow patches constitute important and unique low-temperature ecosystems for microinvertebrates in a temperate mountainous forest. Area of snow algae blooming worldwide are unrecognized novel habitat for tardigrades and rotifers.

scholarly journals Probing the Energetic Metabolism of Resting Cysts under Different Conditions from Molecular and Physiological Perspectives in the Harmful Algal Blooms-Forming Dinoflagellate Scrippsiella trochoidea

2021 ◽  
Vol 22 (14) ◽  
pp. 7325
Author(s):  
Fengting Li ◽  
Aoao Yang ◽  
Zhangxi Hu ◽  
Siheng Lin ◽  
Yunyan Deng ◽  
...  
Keyword(s):  
Low Temperature ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Atp Content ◽  
Energetic Metabolism ◽  
Scrippsiella Trochoidea ◽  
Vegetative Cells ◽  
F1 Atpase ◽  
Atpase Gene ◽  
Resting Cysts

Energetic metabolism is essential in maintaining the viability of all organisms. Resting cysts play important roles in the ecology of dinoflagellates, particularly for harmful algal blooms (HABs)-causative species. However, the energetic metabolism underlying the germination potency maintenance of resting cysts of dinoflagellate have been extremely scarce in studies from physiological and, particularly, molecular perspectives. Therefore, we used the cosmopolitan Scrippsiella trochoidea as a representative of HABs-forming and cyst-producing dinoflagellates in this work to obtain novel insights into the molecular mechanisms, regulating the energetic metabolism in dinoflagellate resting cysts, under different physical condition. As the starting step, we established a cDNA subtractive library via suppression subtractive hybridization (SSH) technology, from which we screened an incomplete sequence for the β subunit of ATP synthase gene (β-F1-ATPase), a key indicator for the status of cell’s energetic metabolism. The full-length cDNA of β-F1-ATPase gene from S.trochoidea (Stβ-F1-ATPase) was then obtained via rapid amplification of cDNA ends (RACE) (Accession: MZ343333). Our real-time qPCR detections, in vegetative cells and resting cysts treated with different physical conditions, revealed that (1) the expression of Stβ-F1-ATPase in resting cysts was generally much lower than that in vegetative cells, and (2) the Stβ-F1-ATPase expressions in the resting cysts under darkness, lowered temperature, and anoxia, and during an extended duration of dormancy, were significantly lower than that in cysts under the condition normally used for culture-maintaining (a 12 h light:12 h dark cycle, 21 °C, aerobic, and newly harvested). Our detections of the viability (via Neutral Red staining) and cellular ATP content of resting cysts, at the conditions corresponding to the abovementioned treatments, showed that both the viability and ATP content decreased rapidly within 12 h and then maintained at low levels within the 4-day experimentation under all the three conditions applied (4 °C, darkness, and anoxia), which are well in accordance with the measurements of the transcription of Stβ-F1-ATPase. These results demonstrated that the energy consumption of resting cysts reaches a low, but somehow stable, level within a short time period and is lower at low temperature, darkness, and anoxia than that at ambient temperature. Our work provides an important basis for explaining that resting cysts survive long-term darkness and low temperature in marine sediments from molecular and physiological levels.

scholarly journals Hindcast and Near Real-Time Monitoring of Green Macroalgae Blooms in Shallow Coral Reef Lagoons Using Sentinel-2: A New-Caledonia Case Study

2021 ◽  
Vol 13 (2) ◽  
pp. 211
Author(s):  
Maële Brisset ◽  
Simon Van Wynsberge ◽  
Serge Andréfouët ◽  
Claude Payri ◽  
Benoît Soulard ◽  
...  
Keyword(s):  
Green Algae ◽  
Algal Blooms ◽  
New Caledonia ◽  
Spectral Indices ◽  
Green Macroalgae ◽  
Spectral Bands ◽  
Algae Blooms ◽  
Trade Offs ◽  
Sentinel 2

Despite the necessary trade-offs between spatial and temporal resolution, remote sensing is an effective approach to monitor macroalgae blooms, understand their origins and anticipate their developments. Monitoring of small tropical lagoons is challenging because they require high resolutions. Since 2017, the Sentinel-2 satellites has provided new perspectives, and the feasibility of monitoring green algae blooms was investigated in this study. In the Poé-Gouaro-Déva lagoon, New Caledonia, recent Ulva blooms are the cause of significant nuisances when beaching. Spectral indices using the blue and green spectral bands were confronted with field observations of algal abundances using images concurrent with fieldwork. Depending on seabed compositions and types of correction applied to reflectance data, the spectral indices explained between 1 and 64.9% of variance. The models providing the best statistical fit were used to revisit the algal dynamics using Sentinel-2 data from January 2017 to December 2019, through two image segmentation approaches: unsupervised and supervised. The latter accurately reproduced the two algal blooms that occurred in the area in 2018. This paper demonstrates that Sentinel-2 data can be an effective source to hindcast and monitor the dynamics of green algae in shallow lagoons.

scholarly journals Detection of Microorganisms in Low-Temperature Water Environments by in situ Generation of Biogenic Nanoparticles

2020 ◽  
Vol 7 ◽  
Author(s):  
Dmitry A. Skladnev ◽  
Lina V. Vasilyeva ◽  
Yulia Yu. Berestovskaya ◽  
Oleg R. Kotsyurbenko ◽  
Sergei V. Kalenov ◽  
...  
Keyword(s):  
Low Temperature ◽  
Water Samples ◽  
Sampling Site ◽  
Ag Nps ◽  
Biological Objects ◽  
In Situ Generation ◽  
The Comparative Study ◽  
Biogenic Nanoparticles ◽  
Temperature Water

A new nanobiotechnological approach for the detection of extraterrestrial Earth-like biological forms is proposed. The approach is based on the ability of microbial cells to reduce artificially added cations with the generation of crystalline nanoparticles (NPs) from zero-valent atoms. The method is named DBNG (Detection of Biogenic Nanoparticles Generation). The subglacial low-temperature oligotrophic Lake Untersee in Antarctica was used as a model of putative extraterrestrial water environments inhabited by Earth-like type microorganisms. The DBNG protocol for the comparative study of microbial communities of low-temperature oligotrophic environments was optimized on the base of experiments with the pure culture of psychroactive bacterium Cryobacterium sp. 1639 isolated earlier from Lake Untersee. The formation of silver nanoparticles (Ag°NPs) has been conducted in natural water samples of three horizons at low temperature (+5°C), which was in the temperature range registered in the Lake Untersee. The generation of biogenic Ag°NPs was detected only at the presence of indigenous microorganisms in all studied samples. No Ag°NPs generation was observed in the lake water samples artificially free of cells or exposed to pasteurization (two types of controls). The miniature microfluidic chip for an automated version of the device, based on using different analytical methods for recording in situ-formed biogenic nanoparticles, is proposed. The device allows the detection of the biological objects directly at the sampling site.

Viewpoints of Dominant Environmental Factors Influencing Algal Blooms

2011 ◽  
Vol 66-68 ◽  
pp. 155-159
Author(s):  
Di Guan ◽  
Da Wen Gao ◽  
Nan Qi Ren ◽  
Yi Fan Li
Keyword(s):  
Environmental Factors ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Meteorological Factors ◽  
Chlorophyll Concentration ◽  
Phytoplankton Growth ◽  
High Biomass ◽  
Coupling Effects ◽  
Factors Influencing

Harmful algal blooms (HABs) are generally known as excessive phytoplankton growth or rapidly concentrate to high biomass. This study summarized the situation of HABs in China, and discussed possible dominant factors stimulating algal blooms by analyzing several actual HABs cases. It was manifested nutrients may affect algae concentration principally, but such impact tended to decease with degradation of background water. Meanwhile the hydrological and meteorological factors expressed greater correlation to chlorophyll concentration under multiple coupling effects of complex environmental factors. For the complex mechanisms, the determination of principle factors which stimulate excessive algal blooms effectively still need further researches, which are suggested to conduct under overall considerations on 3 scales: macro dimension, medium dimension and micro dimension.

scholarly journals Spatial Distribution of Crusts in Antarctic and Greenland Snowpacks and Implications for Snow and Firn Studies

2021 ◽  
Vol 9 ◽  
Author(s):  
Alexander H. Weinhart ◽  
Sepp Kipfstuhl ◽  
Maria Hörhold ◽  
Olaf Eisen ◽  
Johannes Freitag
Keyword(s):  
Spatial Distribution ◽  
Large Scale ◽  
Accumulation Rate ◽  
Sampling Site ◽  
Stable Water Isotopes ◽  
High Accumulation ◽  
Surface Mass ◽  
Antarctic Plateau ◽  
Wide Range ◽  
Surface Snow

The occurrence of snowpack features has been used in the past to classify environmental regimes on the polar ice sheets. Among these features are thin crusts with high density, which contribute to firn stratigraphy and can have significant impact on firn ventilation as well as on remotely inferred properties like accumulation rate or surface mass balance. The importance of crusts in polar snowpack has been acknowledged, but nonetheless little is known about their large-scale distribution. From snow profiles measured by means of microfocus X-ray computer tomography we created a unique dataset showing the spatial distribution of crusts in snow on the East Antarctic Plateau as well as in northern Greenland including a measure for their local variability. With this method, we are able to find also weak and oblique crusts, to count their frequency of occurrence and to measure the high-resolution density. Crusts are local features with a small spatial extent in the range of tens of meters. From several profiles per sampling site we are able to show a decreasing number of crusts in surface snow along a traverse on the East Antarctic Plateau. Combining samples from Antarctica and Greenland with a wide range of annual accumulation rate, we find a positive correlation (R2 = 0.89) between the logarithmic accumulation rate and crusts per annual layer in surface snow. By counting crusts in two Antarctic firn cores, we can show the preservation of crusts with depth and discuss their temporal variability as well as the sensitivity to accumulation rate. In local applications we test the robustness of crusts as a seasonal proxy in comparison to chemical records like impurities or stable water isotopes. While in regions with high accumulation rates the occurrence of crusts shows signs of seasonality, in low accumulation areas dating of the snowpack should be done using a combination of volumetric and stratigraphic elements. Our data can bring new insights for the study of firn permeability, improving of remote sensing signals or the development of new proxies in snow and firn core research.

scholarly journals Remote Sensing Phenology of Antarctic Green and Red Snow Algae Using WorldView Satellites

2021 ◽  
Vol 12 ◽  
Author(s):  
Andrew Gray ◽  
Monika Krolikowski ◽  
Peter Fretwell ◽  
Peter Convey ◽  
Lloyd S. Peck ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Cell Density ◽  
Spatial Resolution ◽  
Satellite Imagery ◽  
Algal Blooms ◽  
Vegetation Index ◽  
Net Primary Productivity ◽  
Snow Algae ◽  
Antarctic Snow ◽  
Sentinel 2

Snow algae are an important group of terrestrial photosynthetic organisms in Antarctica, where they mostly grow in low lying coastal snow fields. Reliable observations of Antarctic snow algae are difficult owing to the transient nature of their blooms and the logistics involved to travel and work there. Previous studies have used Sentinel 2 satellite imagery to detect and monitor snow algal blooms remotely, but were limited by the coarse spatial resolution and difficulties detecting red blooms. Here, for the first time, we use high-resolution WorldView multispectral satellite imagery to study Antarctic snow algal blooms in detail, tracking the growth of red and green blooms throughout the summer. Our remote sensing approach was developed alongside two Antarctic field seasons, where field spectroscopy was used to build a detection model capable of estimating cell density. Global Positioning System (GPS) tagging of blooms and in situ life cycle analysis was used to validate and verify our model output. WorldView imagery was then used successfully to identify red and green snow algae on Anchorage Island (Ryder Bay, 67°S), estimating peak coverage to be 9.48 × 104 and 6.26 × 104 m2, respectively. Combined, this was greater than terrestrial vegetation area coverage for the island, measured using a normalized difference vegetation index. Green snow algae had greater cell density and average layer thickness than red blooms (6.0 × 104 vs. 4.3 × 104 cells ml−1) and so for Anchorage Island we estimated that green algae dry biomass was over three times that of red algae (567 vs. 180 kg, respectively). Because the high spatial resolution of the WorldView imagery and its ability to detect red blooms, calculated snow algal area was 17.5 times greater than estimated with Sentinel 2 imagery. This highlights a scaling problem of using coarse resolution imagery and suggests snow algal contribution to net primary productivity on Antarctica may be far greater than previously recognized.

scholarly journals Combating Algae Blooms

2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Ethan Talley ◽  
Whitney Holden
Keyword(s):  
Algal Blooms ◽  
Genetically Engineered ◽  
Plate Count ◽  
Control Group ◽  
Suitable Candidate ◽  
E Coli ◽  
Development Of Resistance ◽  
Algae Blooms ◽  
Cecropin A ◽  
Successive Generations

Microcystis aeruginosa is a common freshwater cyanobacterium that can form toxic algal blooms that harm other species and the environment. This project studied the effects of the antimicrobial peptide Cecropin A on the growth of M. aeruginosa to assess Cecropin A’s effectiveness as a tool to combat algal blooms and limit their environmental impacts. In this study, different concentrations of Cecropin A were tested on M. aeruginosa, the growth of which was then measured using a plate count. Each concentration of Cecropin A tested resulted in a significant decrease in M. aeruginosa growth compared to the control group, indicating the effectiveness of this peptide at inhibiting M. aeruginosa. Because Cecropin A is a peptide, bacteria can be genetically engineered to produce it for anti-algal applications. This study also analyzed the effects of Cecropin A on the non-pathogenic E. coli K12 in order to study development of antibiotic resistance in this bacterium and determine its feasibility for anti-algal applications such as producing or distributing Cecropin A. The effects of Cecropin A were tested on successive generations to determine if this strain of bacterium can build up a resistance to Cecropin A that would make it a suitable candidate to produce large quantities of this peptide. The results over three 24-hour periods of exposure to Cecropin A seem to indicate a development of resistance to Cecropin A by E. coli K12, suggesting that this bacterium may be suitable for production and/or distribution of Cecropin A for anti-bloom control efforts.

scholarly journals Glacier algae accelerate melt rates on the south-western Greenland Ice Sheet

2020 ◽  
Vol 14 (1) ◽  
pp. 309-330 ◽  
Author(s):  
Joseph M. Cook ◽  
Andrew J. Tedstone ◽  
Christopher Williamson ◽  
Jenine McCutcheon ◽  
Andrew J. Hodson ◽  
...  
Keyword(s):  
Sea Level ◽  
Algal Blooms ◽  
Ice Sheet ◽  
Algal Growth ◽  
Greenland Ice Sheet ◽  
Radiation Absorption ◽  
Transfer Model ◽  
High Biomass ◽  
The South ◽  
Ice Surface

Abstract. Melting of the Greenland Ice Sheet (GrIS) is the largest single contributor to eustatic sea level and is amplified by the growth of pigmented algae on the ice surface, which increases solar radiation absorption. This biological albedo-reducing effect and its impact upon sea level rise has not previously been quantified. Here, we combine field spectroscopy with a radiative-transfer model, supervised classification of unmanned aerial vehicle (UAV) and satellite remote-sensing data, and runoff modelling to calculate biologically driven ice surface ablation. We demonstrate that algal growth led to an additional 4.4–6.0 Gt of runoff from bare ice in the south-western sector of the GrIS in summer 2017, representing 10 %–13 % of the total. In localized patches with high biomass accumulation, algae accelerated melting by up to 26.15±3.77 % (standard error, SE). The year 2017 was a high-albedo year, so we also extended our analysis to the particularly low-albedo 2016 melt season. The runoff from the south-western bare-ice zone attributed to algae was much higher in 2016 at 8.8–12.2 Gt, although the proportion of the total runoff contributed by algae was similar at 9 %–13 %. Across a 10 000 km2 area around our field site, algae covered similar proportions of the exposed bare ice zone in both years (57.99 % in 2016 and 58.89 % in 2017), but more of the algal ice was classed as “high biomass” in 2016 (8.35 %) than 2017 (2.54 %). This interannual comparison demonstrates a positive feedback where more widespread, higher-biomass algal blooms are expected to form in high-melt years where the winter snowpack retreats further and earlier, providing a larger area for bloom development and also enhancing the provision of nutrients and liquid water liberated from melting ice. Our analysis confirms the importance of this biological albedo feedback and that its omission from predictive models leads to the systematic underestimation of Greenland's future sea level contribution, especially because both the bare-ice zones available for algal colonization and the length of the biological growth season are set to expand in the future.

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