scholarly journals Detecting Environmental Stress of Tropical Lagoon Using Abundance-Biomass Curve of Benthic Macroinvertebrate Assemblages (Ebrié lagoon, Côte d'Ivoire, West Africa)

2020 ◽  
pp. 13-25
Author(s):  
Yao Saki Appiah ◽  
Yao Aristide Konan ◽  
Raphael N’doua Etilé ◽  
Zeré Marius Gogbé ◽  
Essetchi Paul Kouamélan
Keyword(s):  
Environmental Changes ◽  
Graphical Method ◽  
Anthropogenic Activities ◽  
Health Assessment ◽  
Fish Mortality ◽  
Benthic Macroinvertebrate ◽  
Environmental Disturbance ◽  
Macroinvertebrate Assemblages ◽  
Assessment Program ◽  
Tropical Lagoon

Sectors IV and V of the Ebrié lagoon are increasingly experiencing fish mortality. The abundance biomass comparison (ABC) is graphical method use to assess the level of environmental disturbance in this area. The aim of the study were to detect the environmental changes caused by anthropogenic activities using ABC curve of benthic macroinvertebrate assemblages presented in the studied areas. Results of the ABC analyses indicated that stations L, K and M are less stressed with biomass curve above abundance curve. Stations N and A recorded a stressed environment with abundance curve above biomass curve. The ABC plots showed that N and A stations could be classified as moderately disturbed and polluted. The Clarke's W index to the benthic macroinvertebrates data, confirmed this situation; it ranged from -0,129 (N) to 0,224 (L). The results of the present study can be extrapolated to other tropical wetland systems to predict the levels of disturbance and to identify characteristic organisms to predict the environmental conditions in the wetland health assessment program.

scholarly journals Effects of anthropogenic impacts on benthic macroinvertebrates assemblages in subtropical mountain streams

2013 ◽  
Vol 103 (4) ◽  
pp. 342-349 ◽  
Author(s):  
Leticia M. Mesa ◽  
María Celina Reynaga ◽  
Marcela del V. Correa ◽  
Martín G. Sirombra
Keyword(s):  
Environmental Changes ◽  
Functional Organization ◽  
Anthropogenic Impacts ◽  
Anthropogenic Activities ◽  
Benthic Fauna ◽  
Total Density ◽  
Functional Feeding Group ◽  
Macroinvertebrate Assemblages ◽  
Feeding Group ◽  
Surrounding Landscape

The nature of the riparian and surrounding landscape has been modified by anthropogenic activities, which may subsequently alter the composition and functional structure of macroinvertebrate assemblages. The effect of these changes on function of benthic fauna is difficult to assess due to the scarce knowledge on functional structures in tropical streams. In this study we evaluate whether sites impacted and unimpacted by anthropogenic alterations differed in assemblage composition and density, richness and diversity of each functional feeding group. The selection of the sites was related to their distinct riparian characteristics, following the QBRy riparian quality index. Collector-gatherer was the dominant functional feeding group, comprising 91% of total density, whereas the proportion of shredders was very low, representing less of 0.5% of total density. Asemblage composition of macroinvertebrates differed between impacted and unimpacted sites. Predators were dominant in taxa number, representing about 60% of total taxa richness. In addition, the diversity and richness of collector-gatherers differed significantly between degraded and unimpacted sites, reflecting the sensitivity of this group to environmental changes and the utility to be used in the assessment of anthropogenic modifications. The results of this study reinforce the idea that riparian corridor management is critical for the distribution of macroinvertebrate assemblages as well as functional organization of lotic streams.

scholarly journals Multi-domain probiotic consortium as an alternative to chemical remediation of oil spills at coral reefs and adjacent sites

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Denise P. Silva ◽  
Helena D. M. Villela ◽  
Henrique F. Santos ◽  
Gustavo A. S. Duarte ◽  
José Roberto Ribeiro ◽  
...  
Keyword(s):  
Microbial Community ◽  
Coral Reefs ◽  
Environmental Changes ◽  
Oil Spills ◽  
Anthropogenic Activities ◽  
Oil Contamination ◽  
Negative Effects ◽  
Corexit 9500 ◽  
Coral Health ◽  
The Impact

Abstract Background Beginning in the last century, coral reefs have suffered the consequences of anthropogenic activities, including oil contamination. Chemical remediation methods, such as dispersants, can cause substantial harm to corals and reduce their resilience to stressors. To evaluate the impacts of oil contamination and find potential alternative solutions to chemical dispersants, we conducted a mesocosm experiment with the fire coral Millepora alcicornis, which is sensitive to environmental changes. We exposed M. alcicornis to a realistic oil-spill scenario in which we applied an innovative multi-domain bioremediator consortium (bacteria, filamentous fungi, and yeast) and a chemical dispersant (Corexit® 9500, one of the most widely used dispersants), to assess the effects on host health and host-associated microbial communities. Results The selected multi-domain microbial consortium helped to mitigate the impacts of the oil, substantially degrading the polycyclic aromatic and n-alkane fractions and maintaining the physiological integrity of the corals. Exposure to Corexit 9500 negatively impacted the host physiology and altered the coral-associated microbial community. After exposure, the abundances of certain bacterial genera such as Rugeria and Roseovarius increased, as previously reported in stressed or diseased corals. We also identified several bioindicators of Corexit 9500 in the microbiome. The impact of Corexit 9500 on the coral health and microbial community was far greater than oil alone, killing corals after only 4 days of exposure in the flow-through system. In the treatments with Corexit 9500, the action of the bioremediator consortium could not be observed directly because of the extreme toxicity of the dispersant to M. alcicornis and its associated microbiome. Conclusions Our results emphasize the importance of investigating the host-associated microbiome in order to detect and mitigate the effects of oil contamination on corals and the potential role of microbial mitigation and bioindicators as conservation tools. Chemical dispersants were far more damaging to corals and their associated microbiome than oil, and should not be used close to coral reefs. This study can aid in decision-making to minimize the negative effects of oil and dispersants on coral reefs.

Middle-to late Holocene environmental changes based on a multi-proxy lagoonal record, Klisova lagoon, Greece

2021 ◽  
Author(s):  
Alexandros Emmanouilidis ◽  
Konstantinos Panagiotopoulos ◽  
Katerina Kouli ◽  
Pavlos Avramidis
Keyword(s):  
Radiocarbon Dating ◽  
Environmental Changes ◽  
Eastern Mediterranean ◽  
Anthropogenic Activities ◽  
Eastern Mediterranean Region ◽  
Anthropogenic Activity ◽  
Palynological Analysis ◽  
Drilling Site ◽  
Geomorphological Changes ◽  
Shallow Water Depth

<p>Coastal wetlands are dynamic environments prone to climatic and anthropogenic forcing and ideal settings to study past climatic and environmental changes.  In the eastern Mediterranean region and particularly in Greece, the climate presents high spatiotemporal diversity, while human activity is a significant factor in shaping the landscape. This study presents a sediment record from Klisova lagoon, situated in central Greece, at the eastern part of Messolonghi lagoon complex. The area is recorded from antiquity to have great anthropogenic activity. The paleoenvironmental synthesis was based on standard sedimentological analysis (grain size, TOC, magnetic susceptibility), joint micropaleontological and palynological analysis, X-ray Fluorescence scanning, and radiocarbon dating. The Bayesian age-depth model is based on radiocarbon dating and yields an age of 4700 cal BP for the base of the recovered sediment sequence. For the last 4700 years, the freshwater influx, the progradation of the Evinos river delta and related geomorphological changes control the environmental conditions (e.g. depth and salinity) in the lagoon system. Prior to 4000 cal BP, a relatively shallow water depth, significant terrestrial/freshwater input and increased weathering in the lagoon area are inferred. Elemental proxies and increased dinoflagellate and foraminifera abundances, which indicate marine conditions with prominent freshwater influxes, point to the gradual deepening of the lagoon recorded at the drilling site up to 2000 cal BP. The marine and freshwater conditions equilibrium sets at 1300 cal BP, and the lagoonal system seems to reach its present state. Maxima of anthropogenic pollen indicators during the Mycenaean (~3200 cal BP), Hellenistic (~ 2200 cal BP) and Late Byzantine (~ 800 cal BP) periods suggest intervals of increased anthropogenic activities in the study area.  </p>

Late Quaternary vegetation dynamics in a biodiversity hotspot, the Uluguru Mountains of Tanzania

2009 ◽  
Vol 72 (1) ◽  
pp. 111-122 ◽  
Author(s):  
Jemma Finch ◽  
Melanie J. Leng ◽  
Rob Marchant
Keyword(s):  
Environmental Changes ◽  
Vegetation History ◽  
Late Quaternary ◽  
Anthropogenic Activities ◽  
Significant Loss ◽  
Environmental Stability ◽  
Forest Composition ◽  
Eastern Arc ◽  
Uluguru Mountains

AbstractLate Quaternary vegetation history and environmental changes in a biodiverse tropical ecosystem are inferred from pollen, charcoal and carbon isotope evidence derived from a ∼ 48,000-yr sedimentary record from the Uluguru Mountains, a component of the Eastern Arc Mountains of Kenya and Tanzania. Results indicate that Eastern Arc forest composition has remained relatively stable during the past ∼ 48,000 yr. Long-term environmental stability of the Eastern Arc forests has been proposed as a mechanism for the accumulation and persistence of species during glacial periods, thus resulting in the diverse forests observed today. The pollen and isotope data presented here indicate some marked changes in abundance but no significant loss in moist forest taxa through the last glacial maximum, thereby providing support for the long-term environmental stability of the Eastern Arc. Anthropogenic activities, including burning and forest clearance, were found to play a moderate role in shaping the mosaic of forest patches and high-altitude grasslands that characterise the site today; however, this influence was tempered by the inaccessibility of the mountain.

scholarly journals Lake water dissolved inorganic carbon dynamics revealed from monthly measurements of radiocarbon in the Fuji Five Lakes, Japan

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kosuke Ota ◽  
Yusuke Yokoyama ◽  
Yosuke Miyairi ◽  
Shinya Yamamoto ◽  
Toshihiro Miyajima
Keyword(s):  
Lake Water ◽  
Inorganic Carbon ◽  
Environmental Changes ◽  
Dissolved Inorganic Carbon ◽  
Anthropogenic Activities ◽  
Aquatic Organisms ◽  
Human Society ◽  
History Of ◽  
Lake Waters ◽  
Reservoir Age

Lakes are sensitive recorders of anthropogenic activities, as human society often develops in their vicinity. Lake sediments thus have been widely used to reconstruct the history of environmental changes in the past, anthropogenic, or otherwise, and radiocarbon dating provides chronological control of the samples. However, specific values of radiocarbon in different carbon reservoirs due to the different pathways of radiocarbon from the upper atmosphere to the lake, called the radiocarbon reservoir age, is always difficult to evaluate because of dynamic processes in and around lakes. There are few systematic studies on radiocarbon reservoir ages for lakes owing to the complex radiocarbon transfer processes for lakes. Here, we investigate lake waters of the Fuji Five Lakes with monthly monitoring of the radiocarbon reservoir effects. Radiocarbon from dissolved inorganic carbon (DIC) for groundwater and river water is also measured, with resulting concentrations (Δ14C) at their lowest at Lake Kawaguchi in August 2018 (–122.4 ± 3.2‰), and at their highest at Lake Motosu in January 2019 (–22.4 ± 2.5‰), despite a distance of 25 km. However, winter values in both lakes show similar trends of rising Δ14C (about 20‰). Our lake water DIC Δ14C results are compared to previously published records obtained from sediments in Lake Motosu and Lake Kawaguchi. These suggest that total organic carbon and compound-specific radiocarbon found in sediments are heavily influenced by summer blooms of aquatic organisms that fix DIC in water. Thus, future studies to conduct similar analyses at the various lakes would be able to provide further insights into the carbon cycle around inland water, namely understanding the nature of radiocarbon reservoir ages.

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