scholarly journals Lake sedimentary DNA to reveal long-term changes in aquatic biodiversity and ecosystem functioning

2021 ◽  
Vol 4 ◽  
Author(s):  
Isabelle Domaizon
Keyword(s):  
Community Dynamics ◽  
Temporal Dynamics ◽  
Critical Research ◽  
Aquatic Biodiversity ◽  
Biological Variables ◽  
Long Term Changes ◽  
Research Questions ◽  
Population And Community Dynamics ◽  
Emerging Topics

The emergence of molecular analyses based on the sequencing of sedimentary DNA has opened up many new areas of inquiry in paleolimnology. DNA preserved in sediments (SedDNA) offers the possibility to consider taxa that were traditionally not accessible because they do not leave distinct morphological fossils. Recent applications that considered a diversity of biological groups (including bacteria, protists, zooplankton, fish) illustrate how efficiently SedDNA-based methods complement both classical paleolimnology proxies and limnological data. The knowledge gained from this approach is very diverse in scope, ranging from quantifying natural variability in population and community dynamics to understanding how these biological variables respond to anthropogenic disturbances and climatic change. The use of lake sedimentary DNA to track long-term changes in aquatic biota is a rapidly advancing field of research. Based on recent applications, this presentation illustrates (i) the potential and challenges associated with the study of SedDNA to address critical research questions in lacustrine ecology (ii) the main methodological precautions to be taken into account for implementing these types of DNA analyses (i.e. best practices) and (iii) the emerging topics that could be addressed using sedimentary DNA, in particular to reconstruct the temporal dynamics of lacustrine biodiversity.

ESTIMATION OF LONG-TERM CHANGES IN QUALITATIVE CHARACTERISTICS OF THE OKA RIVER RUNOFF

2021 ◽  
pp. 98-104
Author(s):  
G. KH. ISMAIYLOV ◽  
◽  
N. V. MURASCHENKOVA ◽  
I. G. ISMAIYLOVA
Keyword(s):  
River Runoff ◽  
Maximum Concentration ◽  
Temporal Dynamics ◽  
Ammonium Nitrogen ◽  
Oil Products ◽  
Copper Compounds ◽  
Long Term Changes ◽  
The City ◽  
Qualitative Characteristics

The results of the analysis and assessment of long-term changes in the qualitative characteristics of the Oka River runoff are presented. To analyze the temporal dynamics of the variability of the average annual and maximum concentrations of pollutants in the runoff of the Oka River, we used long-term observational data on typical pollutants for the period 1984-2019. The assessment of the state of the quality of surface waters of the Oka River was carried out according to the values of the concentrations of pollutants in the upper, middle and lower reaches of the river. The dynamics of the main pollutants of the following indicators is considered: ammonium nitrogen, oil products, copper and zinc compounds and easily oxidized organic substances. It was found that in the upper reaches of the river (according to observations of the Oka – Orel city) the main pollutants are ammonium nitrogen and copper compounds, the average annual concentrations of which respectively increased to 9 values. A similar situation was observed downstream of the river (the Oka River – Kaluga city). As a result of the analysis, it was revealed that more noticeable changes in the concentration of pollutants are observed in the section of the river from the city of Murom to the city of Dzerzhinsk. Near the city of Murom, the content of oil products in the water sharply increases. From the beginning of the study period (1984) and until 1995, the average annual concentration varied from 5 to 30 values, and the maximum concentration in the year in creased to 87 values. After 2000, the content of oil products in water dropped sharply and the average annual value did not exceed 3 values, and the maximum concentration was 4-6 values. The paper analyzes the frequency of cases of exceeding the maximum permissible concentrations of pollutants in the Oka River in the mouth of the river. There was a high repeatability of the content of copper compounds in water, which varied from 70 to 88%. The frequency of cases of excess of easily oxidized organic matter in the mouth of the Oka River varied from 64 to 74%. Relatively low, although stable, the repeatability of the content of oil products in water remained, which ranged from 23 to 42%.

scholarly journals Advancing the long view of ecological change in tundra systems

2013 ◽  
Vol 368 (1624) ◽  
pp. 20120477 ◽  
Author(s):  
Eric Post ◽  
Toke T. Høye
Keyword(s):  
Species Interactions ◽  
Community Dynamics ◽  
Ecological Change ◽  
Special Issue ◽  
Research Personnel ◽  
Ecological Responses ◽  
History Of ◽  
Population And Community Dynamics ◽  
Long Term Studies

Despite uncertainties related to sustained funding, ideological rivalries and the turnover of research personnel, long-term studies and studies espousing a long-term perspective in ecology have a history of contributing landmark insights into fundamental topics, such as population- and community dynamics, species interactions and ecosystem function. They also have the potential to reveal surprises related to unforeseen events and non-stationary dynamics that unfold over the course of ongoing observation and experimentation. The unprecedented rate and magnitude of current and expected abiotic changes in tundra environments calls for a synthetic overview of the scope of ecological responses these changes have elicited. In this special issue, we present a series of contributions that advance the long view of ecological change in tundra systems, either through sustained long-term research, or through retrospective or prospective modelling. Beyond highlighting the value of long-term research in tundra systems, the insights derived herein should also find application to the study of ecological responses to environmental change in other biomes as well.

Intra-annual fluctuations dominating temporal dynamics of benthic diatom assemblages in a Chinese mountainous river

2020 ◽  
Vol 56 ◽  
pp. 22
Author(s):  
Shuhan Guo ◽  
Fengzhi He ◽  
Tao Tang ◽  
Lu Tan ◽  
Qinghua Cai
Keyword(s):  
Community Dynamics ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Multivariate Time Series ◽  
Multiple Scale ◽  
Benthic Diatom ◽  
Diatom Community ◽  
Diatom Communities ◽  
Mountainous River

Understanding temporal dynamics of community may provide insights on biological responses under environmental changes. However, our knowledge on temporal dynamics of river organisms is still limited. In the present study, we employed a multivariate time-series modeling approach with a long-term dataset (i.e. 72 consecutive months) to investigate temporal dynamics of benthic diatom communities in four sites located in a Chinese mountainous river network. We hypothesized that: (1) there are multi-scale temporal dynamics within the diatom community; (2) intra-annual fluctuations dominate the community dynamics; (3) diatom species composing the community respond distinctly to environmental changes. We found that intra-annual fluctuations with periodicities <12 months explained 8.1–16.1% of community variation. In contrast, fluctuations with periodicities of 13–36 months and 37–72 months only accounted for 1.1–5.9% and 2.8–9.7% of variance in diatom community dynamics, respectively. Taxa correlating significantly to each significant RDA axis (namely, RDA taxa group) displayed distinct temporal dynamics. Conductivity, total nitrogen, and pH were important to most RDA taxa groups across the four sites while their effects were group-specific. We concluded that intra-annual dynamics dominated temporal variation in diatom communities due to community responses to local environmental fluctuations. We suggest that long-term monitoring data are valuable for identifying multiple-scale temporal dynamics within biological communities.

scholarly journals Lake Sedimentary DNA Research on Past Terrestrial and Aquatic Biodiversity: Overview and Recommendations

Quaternary ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 6
Author(s):  
Eric Capo ◽  
Charline Giguet-Covex ◽  
Alexandra Rouillard ◽  
Kevin Nota ◽  
Peter D. Heintzman ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Recent Literature ◽  
State Of The Art ◽  
Current Knowledge ◽  
Aquatic Biota ◽  
Aquatic Biodiversity ◽  
Sequencing Technologies ◽  
Long Term Changes ◽  
Original Case

The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original case studies, we synthesize the state-of-the-art analytical procedures for effective sampling, extraction, amplification, quantification and/or generation of DNA inventories from sedimentary ancient DNA (sedaDNA) via high-throughput sequencing technologies. We provide recommendations based on current knowledge and best practises.

Eco-evolutionary Dynamics

2016 ◽  
Author(s):  
Andrew P. Hendry
Keyword(s):  
Community Dynamics ◽  
Evolutionary Dynamics ◽  
Natural Populations ◽  
Evolutionary Change ◽  
Future Research ◽  
Adaptive Divergence ◽  
New Directions ◽  
Research Questions ◽  
Population And Community Dynamics ◽  
Key Aspects

In recent years, scientists have realized that evolution can occur on timescales much shorter than the “long lapse of ages” emphasized by Darwin—in fact, evolutionary change is occurring all around us all the time. This book provides an authoritative and accessible introduction to eco-evolutionary dynamics, a cutting-edge new field that seeks to unify evolution and ecology into a common conceptual framework focusing on rapid and dynamic environmental and evolutionary change. The book covers key aspects of evolution, ecology, and their interactions. Topics range from natural selection, adaptive divergence, ecological speciation, and gene flow to population and community dynamics, ecosystem function, plasticity, and genomics. The book evaluates conceptual and methodological approaches, and draws on empirical data from natural populations—including those in human-disturbed environments—to tackle a number of classic and emerging research questions. It also discusses exciting new directions for future research at the intersection of ecology and evolution. The book reveals how evolution and ecology interact strongly on short timescales to shape the world we see around us.

scholarly journals Biological complexity behind plankton system functioning: Synthesis and perspectives from a marine Long Term Ecological Research

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Domenico D'Alelio
Keyword(s):  
Community Dynamics ◽  
Environmental Changes ◽  
Ecological Research ◽  
Gulf Of Naples ◽  
Long Term Ecological Research ◽  
System Functioning ◽  
Species Evolution ◽  
Population And Community Dynamics ◽  
Different Levels

The functioning of natural communities is the cumulative outcome of multifaceted and intersecting ecological and evolutionary processes occurring at species level. Species are not stable entities but evolve in consequence of contingent factors including the relationships they establish with the environment and other co-occurring species. Studying ecosystems with an eco-evo approach, i.e., by explicitly considering species evolution and interactions, is thus an essential step to envisioning their adaptation to environmental changes. Such approach is particularly suitable for studying plankton, a community of both rapidly evolving and strongly interconnected species. In this context, Long Term Ecological Research studies (LTER) represent a promising approach to explore nature at different levels of complexity, from species to ecosystems. Herein, I examine the most recent results coming from the three-decades plankton LTER ‘MareChiara’ (LTER-MC) in the Gulf of Naples (Mediterranean Sea, Italy) and discuss their suitability in deepening knowledge on: i) evolutionary bases to plankton biodiversity (i.e., the founding property of both species and community adaptive potential); ii) ecological and evolutionary determinants of population and community dynamics; and iii) biological mechanisms behind plankton system functioning.

A 260 000-year reconstruction of diatom community dynamics and photosynthetic pigments in Lake Chala, a tropical crater lake

2020 ◽  
Author(s):  
Heidi Tanttu ◽  
Christine Cocquyt ◽  
Dirk Verschuren ◽  
Elie Verleyen
Keyword(s):  
Crater Lake ◽  
Community Dynamics ◽  
Temporal Dynamics ◽  
Diatom Community ◽  
Phytoplankton Primary Production ◽  
Fossil Pigments ◽  
Last Glacial ◽  
Deep Mixing ◽  
The Last Glacial

&lt;p&gt;Lake Chala is a c. 90 m deep meromictic, oligotrophic crater lake near Mt. Kilimanjaro in equatorial East Africa. This sub-humid tropical region experiences two rainy seasons separated by a long dry season in June-August, when deep mixing fuels the epilimnion with nutrients resulting in increased phytoplankton primary production. Within the ICDP DeepCHALLA project, a 215-m long, continuous sediment sequence was obtained, which provides a unique opportunity to study long-term climate dynamics and aquatic ecosystem response during the past c. 260 000 years. Here we analyzed fossil pigments and diatom assemblages to reconstruct temporal dynamics in the lake&amp;#8217;s phytoplankton community structure with millennial-scale resolution. Fossil pigments were analyzed using high-performance liquid chromatography, and a minimum of 400 valves were counted and identified with best-possible taxonomic discrimination from sediment samples taken at c. 800-yr intervals throughout the last glacial cycle (back to c. 160 kyr BP) and at c. 1600-yr intervals throughout earlier lake history. The most abundant pigments were zeaxanthin and lutein, reflecting the presence of cyanobacteria and green algae. Despite the high diatom content of the sediments, the diatom marker pigment fucoxanthin was almost absent, which we attribute to its labile nature. A small cyclotelloid diatom resembling the tychoplanktonic species &lt;em&gt;Discostella stelligera&lt;/em&gt; at the base of the sequence probably reflects open-water conditions with the proximity of littoral habitats during the early filling stages of lake ontogeny. High proportions (20-50%) of an &lt;em&gt;Encyonema&lt;/em&gt; species at c. 240-230 kyr BP indicate increased availability of benthic habitats, possibly because of a marked low-stand at the time of early sediment infilling when the central ash cone on the basin floor was still exposed. A phase of abundant needle-like &lt;em&gt;Nitzschia&lt;/em&gt; and generally higher, yet fluctuating, pigment concentrations suggest a relatively moist environment with deep water and a stable stratification at c. 220-140 kyr BP. After c. 140 kyr BP, &lt;em&gt;Afrocymbella barkeri&lt;/em&gt; appears for the first time, and from then onwards until the modern times the diatom community is composed of fluctuating abundances of &lt;em&gt;Afrocymbella&lt;/em&gt; and needle-like &lt;em&gt;Nitzschia&lt;/em&gt; taxa. The highest diatom biovolumes yet pronounced low carotenoid concentrations occur during the &lt;em&gt;Afrocymbella&lt;/em&gt;-dominated (up to 100 %) intervals between c. 110 and 90 kyr BP and between c. 22 and 17 kyr BP, which broadly coincide with the MIS5 African megadrought and the Last Glacial Maximum, respectively. This suggests that during those time periods, the lake experienced pronounced dry and windy climate conditions, which triggered relatively deep mixing. This probably enhanced internal nutrient cycling and the injecting of oxygen to the bottom waters, which facilitated diatom growth in the epilimnion and resulted in pigment degradation in the hypolimnion. Superimposed on these long-term patterns, we found many short-term fluctuations in the appearance of different &lt;em&gt;Nitzschia&lt;/em&gt; taxa, which may reflect stochastic colonization and extinction events, rather than actual climate-driven changes in the abiotic environment of Lake Chala.&lt;/p&gt;

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