Aquatic community structure as sentinel of recent environmental changes unraveled from lake sedimentary records from the Atacama Desert, Chile

<p>Espiritu Santo is one of the 82 islands of the archipelago of Vanuatu and is the largest, highest, and most biodiverse of the insular country. Climatic changes linked to El Ni&#241;o and extreme events such as cyclones and volcanic eruptions are a daily challenge in this remote area. These events can be recorded in sedimentary archives. Here we present a multi-proxy investigation of sediment cores retrieved from two small lakes located on the West coast of Espiritu Santo. Although the records span the last millennium, high-resolution radiocarbon dating of macrofossils reveals a rapid accumulation of sediment in the past 100 years. The high accumulation rate coupled with the high-resolution dating of freshwater sediments allows us to compare the <sup>14</sup>C bomb curve with the biogeochemical proxies of the sedimentary records. The results can then be validated against written and oral historical records linked with the societal perception of recent environmental changes in this vulnerable ecosystem.</p><div> <div title="Translate selected text"></div> <div title="Play"></div> <div title="Copy text to Clipboard"></div> </div>

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Prokaryotic Community Structure and Metabolisms in Shallow Subsurface of Atacama Desert Playas and Alluvial Fans After Heavy Rains: Repairing and Preparing for Next Dry Period

Frontiers in Microbiology ◽

10.3389/fmicb.2019.01641 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 7

Author(s):

Miguel Ángel Fernández-Martínez ◽

Rita dos Santos Severino ◽

Mercedes Moreno-Paz ◽

Ignacio Gallardo-Carreño ◽

Yolanda Blanco ◽

...

Keyword(s):

Community Structure ◽

Atacama Desert ◽

Alluvial Fans ◽

Prokaryotic Community ◽

Dry Period ◽

Shallow Subsurface ◽

Heavy Rains

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Climate change negatively impacts dominant microbes in the sediments of a High Arctic lake

10.1101/705178 ◽

2019 ◽

Cited By ~ 1

Author(s):

Graham A. Colby ◽

Matti O. Ruuskanen ◽

Kyra A. St. Pierre ◽

Vincent L. St. Louis ◽

Alexandre J. Poulain ◽

...

Keyword(s):

Climate Change ◽

Community Structure ◽

Environmental Changes ◽

High Arctic ◽

The Arctic ◽

Large Lake ◽

Spatial Gradients ◽

Functional Potential ◽

High Runoff ◽

Sediment Microbes

AbstractTemperatures in the Arctic are expected to increase dramatically over the next century, yet little is known about how microbial communities and their underlying metabolic processes will be affected by these environmental changes in freshwater sedimentary systems. To address this knowledge gap, we analyzed sediments from Lake Hazen, NU Canada. Here, we exploit the spatial heterogeneity created by varying runoff regimes across the watershed of this uniquely large lake at these latitudes to test how a transition from low to high runoff, used as one proxy for climate change, affects the community structure and functional potential of dominant microbes. Based on metagenomic analyses of lake sediments along these spatial gradients, we show that increasing runoff leads to a decrease in taxonomic and functional diversity of sediment microbes. Our findings are likely to apply to other, smaller, glacierized watersheds typical of polar or high latitude / high altitudes ecosystems; we can predict that such changes will have far reaching consequences on these ecosystems by affecting nutrient biogeochemical cycling, the direction and magnitude of which are yet to be determined.

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Effects of Elevation and Distance from Highway on the Abundance and Community Structure of Bacteria in Soil along Qinghai-Tibet Highway

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph182413137 ◽

2021 ◽

Vol 18 (24) ◽

pp. 13137

Author(s):

Zhuocheng Liu ◽

Yangang Yang ◽

Shuangxuan Ji ◽

Di Dong ◽

Yinruizhi Li ◽

...

Keyword(s):

Community Structure ◽

Soil Bacteria ◽

Environmental Changes ◽

Chemical Properties ◽

Soil Nutrient ◽

Nutrient Content ◽

Tibet Plateau ◽

Nitrifying Bacteria ◽

Ecological Environment ◽

The Impact

In recent years, highway construction in the Qinghai-Tibet Plateau (QTP) has developed rapidly. When the highway passes through grassland, the soil, vegetation, and ecological environment along the line are disturbed. However, the impact on soil bacteria is still unclear. Soil bacteria play an important role in the ecological environment. The Qinghai-Tibet Highway (QTH) was selected as the research object to explore the changes in bacterial community structure, vegetation, soil, and other indicators. The results showed that the highway-related activities increased the degradation of vegetation along the road, significantly changed the physical and chemical properties of soil, and caused heavy metal pollution. These environmental factors affected the diversity and community structure of soil bacteria. This kind of disturbance shows a trend of gradually increasing from near to far from the highway. Gemmatimonas, Terrimonas, Nitrospira and Bacillus are more tolerant to environmental changes along the highway, while Barnesiella, and Blastococcus are more sensitive. The content of nitrate decreased and the content of ammonium nitrogen increased in the disturbed area, increasing the abundance of nitrifying bacteria. Therefore, the main factor of the disturbance of the QTH on the grassland is the decline of soil nutrient content, and the supplement of soil nutrients such as carbon and nitrogen should be taken into account in the process of ecological restoration of grassland along the line.

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STUDI KEANEKARAGAMAN DAN STRUKTUR KOMUNITAS PERIFITON DI PERAIRAN SUNGAI COBAN RONDO MALANG

Jurnal Teknologi Terapan: G-Tech ◽

10.33379/gtech.v1i2.275 ◽

2020 ◽

Vol 1 (2) ◽

pp. 93-97

Author(s):

Zainal Abidin

Keyword(s):

Water Quality ◽

Cluster Analysis ◽

Community Structure ◽

Environmental Changes ◽

Aquatic Organisms ◽

Dominance Index ◽

Periphyton Community ◽

Similarity Indices ◽

And Cluster Analysis ◽

Index Value

Periphyton is a community of microorganisms that live attached to or adjacent to a substrate sink. For aquatic organisms, periphyton habitats have a relatively fixed. With it is so, the changes of water quality and substrate greatly affects the composition of his life and abundance. Periphyton composition and abundance depends on the tolerance or sensitivity to environmental changes. This study aims to determine each periphyton community in responding to changes in habitat quality by way of adjustment in community structure. The methodology used in this prektikum involves taking data from four stations along the river Coban Rondo, in each station there are 3 replicates. And take measurements of factors such environments as supportive data turbidity, flow rate, pH, and depth. Analyzed using Simpson's Dominance Index to determine the type of periphyton dominance, as well as morisita similarity indices and cluster analysis. The results showed that the diversity in each station belonging to the category of high (H more than 3.32) because the obtained value of the index H' between 3.2 to 3.48. Species that dominate from the four stations is Pinularia with an average Index Value Important (IVI) 31,5.

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Short Communication: Community structure and diversity of Odonata in Suranadi Natural Park, West Lombok Indonesia

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d210238 ◽

2020 ◽

Vol 21 (2) ◽

Author(s):

MOHAMMAD LIWA ILHAMDI ◽

AGIL AL IDRUS ◽

DIDIK SANTOSO ◽

Gito Hadiprayitno

Keyword(s):

Community Structure ◽

Data Collection ◽

Short Communication ◽

Environmental Changes ◽

Diversity Index ◽

Scientific Information ◽

Ecosystem Change ◽

Survey Method ◽

Transect Line ◽

Natural Park

Abstract. Ilhamdi ML, Al Idrus A, Santoso D, Hadiprayitno G. 2020. Short Communication: Community structure and diversity of Odonata in Suranadi Natural Park, West Lombok Indonesia. Biodiversitas 21: 718-723. Odonata is an order of insects. The life cycle of this order is dependent on freshwater habitat. Sensitivity to environmental changes causes odonates to be important bioindicators of ecosystem change. The importance of the ecological role of odonates is not followed by adequate scientific information on Odonata communities, especially in the Suranadi Natural Park (SNP). The study aimed to monitor the existence and community structure of Odonata in the SNP area every six months in period. The data collection technique was using a survey method by following the transect line, namely the waterway transect line (WTL), plantation border transect (PT) and settlement border transect (ST). Data collection was done 4 times from April to May 2019, once every 2 weeks. The sampling was done twice in the morning from 08.00 to 11.00 AM and in the afternoon from 03.00 to 05.00 PM. Data were analyzed using the relative frequency equation and Diversity Index. The results showed that there were 16 species of odonates consisting of the family Libellulidae (11 species), Platycnemididae (1 species), Chlorocyphidae (1 species), and Coegrinidae (3 species). Orthetrum sabina, Neurothemis ramburii, Diplacodes trivialis, Gynacantha subinterrupta, Copera marginipes, and Pantala flavescens, are species that are present in all of each observation sites. The waterway transect has the highest diversity index (2.027), followed by settlement transect (1.367), and the lowest is plantation transect (1.131).

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Diversity and distribution of heterotrophic flagellates in seawater of the Powell Basin, Antarctic Peninsula

Polar Research ◽

10.33265/polar.v40.5389 ◽

2021 ◽

Vol 40 ◽

Author(s):

Zhiyi Chen ◽

Jianfeng He ◽

Shunan Cao ◽

Zhibo Lu ◽

Musheng Lan ◽

...

Keyword(s):

Community Structure ◽

Environmental Factors ◽

Antarctic Peninsula ◽

Environmental Changes ◽

Bacterial Biomass ◽

Heterotrophic Nanoflagellates ◽

Heterotrophic Flagellates ◽

Polar Regions ◽

Biological Interactions ◽

Essential Components

Heterotrophic flagellates are essential components of the marine microbial food web. However, how the changes in flagellate populations reflect environmental changes in marine ecosystems is still unclear, especially in polar regions. In this study, we used pyrosequencing to examine the community structure of heterotrophic flagellates (HFs) in the Powell Basin’s surface waters of the northern Antarctic Peninsula. OTUs (operational taxonomic units) of different taxa and the correlations between community structure and environmental factors were analysed. Eight taxa of HFs were selected for the principal analysis: Telonemia, Picozoa, Rhizaria, Amoebozoa, Apusomonas, Centrohelida, Choanomonada and marine stramenopiles (MASTs). The HFs were defined as heterotrophic picoflagellates (HPFs; <3 μm) and heterotrophic nanoflagellates (HNFs; >3 μm, <20 μm), which had similar dominant phyla (MASTs and Telonemia). However, their taxonomic composition differed. Environmental factors exerted similar effects on the community structure of both HPFs and HNPs. Compared with the correlation between HPF and environmental factors, the correlation between HNF and environmental factors was stronger. Salinity, bacterial biomass and the biological interactions amongst dominant taxa were the main variables to influence the diversity and community structure of HFs.

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Changes in Heterotrophic Picoplankton Community Structure after Induction of a Phytoplankton Bloom under Different Light Regimes

Diversity ◽

10.3390/d11100195 ◽

2019 ◽

Vol 11 (10) ◽

pp. 195 ◽

Cited By ~ 1

Author(s):

Karayanni ◽

Kormas ◽

Moustaka-Gouni ◽

Sommer

Keyword(s):

Community Structure ◽

Bacterial Community ◽

Relative Abundance ◽

Environmental Changes ◽

Phytoplankton Bloom ◽

Phytoplankton Growth ◽

Light Regimes ◽

Operational Taxonomic Units ◽

Abundant Otus

Bacterial and archaeal diversity and succession were studied during a mesocosm experiment that investigated whether changing light regimes could affect the onset of phytoplankton blooms. For this, 454-pyrosequencing of the bacterial V1-V3 and archaeal V3-V9 16S rRNA regions was performed in samples collected from four mesocosms receiving different light irradiances at the beginning and the end of the experiment and during phytoplankton growth. In total, 46 bacterial operational taxonomic units (OTUs) with ≥1% relative abundance occurred (22–34 OTUs per mesocosm). OTUs were affiliated mainly with Rhodobacteraceae, Flavobacteriaceae and Alteromonadaceae. The four mesocosms shared 11 abundant OTUs. Dominance increased at the beginning of phytoplankton growth in all treatments and decreased thereafter. Maximum dominance was found in the mesocosms with high irradiances. Overall, specific bacterial OTUs had different responses in terms of relative abundance under in situ and high light intensities, and an early phytoplankton bloom resulted in different bacterial community structures both at high (family) and low (OTU) taxonomic levels. Thus, bacterial community structure and succession are affected by light regime, both directly and indirectly, which may have implications for an ecosystem’s response to environmental changes.

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Evaluating environmental drivers of spatial variability in free-living nematode assemblages along the Portuguese margin

Biogeosciences ◽

10.5194/bg-14-651-2017 ◽

2017 ◽

Vol 14 (3) ◽

pp. 651-669 ◽

Cited By ~ 8

Author(s):

Lidia Lins ◽

Frederik Leliaert ◽

Torben Riehl ◽

Sofia Pinto Ramalho ◽

Eliana Alfaro Cordova ◽

...

Keyword(s):

Community Structure ◽

Environmental Factors ◽

Food Availability ◽

Environmental Changes ◽

Shelf Break ◽

Environmental Drivers ◽

Continental Margins ◽

Sediment Heterogeneity ◽

Iberian Margin ◽

Upper Slope

Abstract. Understanding processes responsible for shaping biodiversity patterns on continental margins is an important requirement for comprehending anthropogenic impacts in these environments and further management of biodiversity. Continental margins perform crucial functions linked to key ecological processes which are mainly structured by surface primary productivity and particulate organic matter flux to the seafloor, but also by heterogeneity in seafloor characteristics. However, to what extent these processes control local and regional biodiversity remains unclear. In this study, two isobathic parallel transects located at the shelf break (300–400 m) and upper slope (1000 m) of the western Iberian margin were used to test how food input and sediment heterogeneity affect nematode diversity independently from the spatial factors geographical distance and water depth. We also examined the potential role of connectedness between both depth transects through molecular phylogenetic analyses. Regional generic diversity and turnover were investigated at three levels: within a station, between stations from the same depth transect, and between transects. High variability in food availability and high sediment heterogeneity at the shelf-break transect were directly linked to high diversity within stations and higher variation in community structure across stations compared to the upper slope transect. Contrastingly, environmental factors (food availability and sediment) did not vary significantly between stations located at the upper slope, and this lack of differences were also reflected in a low community turnover between these deeper stations. Finally, differences in nematode communities between both transects were more pronounced than differences within each of the isobathic transects, but these changes were paralleled by the previously mentioned environmental changes. These results suggest that changes in community structure are mainly dictated by environmental factors rather than spatial differences at the western Iberian margin. Furthermore, phylogenetic relationships revealed no evidence for depth-endemic lineages, indicating regular species interchanges across different depths.

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