scholarly journals Population dynamics of Cymodocea nodosa under future ocean scenarios.

2018 ◽  
Author(s):  
Amrit K Mishra
Keyword(s):  
Population Dynamics ◽  
Elevated Co2 ◽  
Marine Ecosystem ◽  
Co2 Enrichment ◽  
Cymodocea Nodosa ◽  
Long Term Effects ◽  
Leaf Production ◽  
Co2 Concentrations ◽  
Carbon Dioxide Co2

Rising carbon dioxide (CO2) concentrations in the atmosphere will increase the average pCO2 level in the world oceans, which will have a knock-on effect on the marine ecosystem. Coastal seagrass communities are predicted to benefit from the increase in CO2 levels, but long-term effects of elevated CO2 on seagrass communities are less understood. Population reconstruction techniques were used to investigate the population dynamics of Cymodocea nodosa meadows, exposed to long term elevated CO2 at volcanic seeps off Greece and Italy. Effect of elevated CO2 was noticed on the growth, morphometry, density, biomass and age structure at CO2 seeps than reference sites. Above to below ground biomass ratio of C. nodosa were higher at CO2 seeps. The shoot age and shoot longevity of plants were lower at seeps. The present recruitment (sampled year) of the seagrass were higher than long-term average recruitment of the communities near the seeps. Carbon to nitrogen ratios (%DW) and annual leaf production of C. nodosa were higher in leaves at seeps. This study suggests under long-term CO2 enrichment C. nodosa production increases, but the plant survival rate decreases because of other co-factors such as nutrient availability and trace metal toxicity. Therefore, along with high CO2 other factors must be taken into consideration while predicting effects of future CO2 concentrations.

scholarly journals Long-term effects of elevated CO2 on the population dynamics of the seagrass Cymodocea nodosa: Evidence from volcanic seeps

2020 ◽  
pp. 111824
Author(s):  
A.K. Mishra ◽  
S. Cabaço ◽  
C.B. de los Santos ◽  
E.T. Apostolaki ◽  
S. Vizzini ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Elevated Co2 ◽  
Cymodocea Nodosa ◽  
Long Term Effects

scholarly journals Long-Term Effects of Elevated Co2 on the Population Dynamics of The Seagrass Cymodocea Nodosa: Evidence from Volcanic Seeps

2020 ◽  
Author(s):  
Amrit Kumar Mishra ◽  
Susana Cabaco ◽  
Carmen de los Santos ◽  
Eugenia Apostolaki ◽  
Salvatrice Vizzini ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Elevated Co2 ◽  
Reproductive Output ◽  
Cymodocea Nodosa ◽  
Long Term Effects ◽  
Production Rates ◽  
Population Reconstruction ◽  
Short And Long Term ◽  
First Time

We used population reconstruction techniques to assess for the first time the population dynamics of a seagrass, Cymodocea nodosa, exposed to long-term elevated CO2 near three volcanic seeps and compare them with reference sites away from the seeps. Under high CO2, the density of shoots and of individuals (apical shoots), and the vertical and horizontal elongation and production rates, were higher. Nitrogen effects on rhizome elongation and production rates and on biomass, were stronger than CO2 as these were highest at the location where the availability of nitrogen was highest. At the seep where the availability of CO2 was highest and nitrogen lowest, density of shoots and individuals were highest, probably due to CO2 effects on shoot differentiation and induced reproductive output, respectively. In all three seeps there was higher short- and long-term recruitment and growth rates around zero, indicating that elevated CO2 increases the turnover of C. nodosa shoots.

scholarly journals Simulating Long-Term Development of Greenhouse Gas Emissions, Plant Biomass, and Soil Moisture of a Temperate Grassland Ecosystem under Elevated Atmospheric CO2

Agronomy ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 50
Author(s):  
Ralf Liebermann ◽  
Lutz Breuer ◽  
Tobias Houska ◽  
David Kraus ◽  
Gerald Moser ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Elevated Co2 ◽  
Biomass Production ◽  
Atmospheric Co2 ◽  
N2o Emissions ◽  
Gas Emissions ◽  
Co2 Concentrations

The rising atmospheric CO2 concentrations have effects on the worldwide ecosystems such as an increase in biomass production as well as changing soil processes and conditions. Since this affects the ecosystem’s net balance of greenhouse gas emissions, reliable projections about the CO2 impact are required. Deterministic models can capture the interrelated biological, hydrological, and biogeochemical processes under changing CO2 concentrations if long-term observations for model testing are provided. We used 13 years of data on above-ground biomass production, soil moisture, and emissions of CO2 and N2O from the Free Air Carbon dioxide Enrichment (FACE) grassland experiment in Giessen, Germany. Then, the LandscapeDNDC ecosystem model was calibrated with data measured under current CO2 concentrations and validated under elevated CO2. Depending on the hydrological conditions, different CO2 effects were observed and captured well for all ecosystem variables but N2O emissions. Confidence intervals of ensemble simulations covered up to 96% of measured biomass and CO2 emission values, while soil water content was well simulated in terms of annual cycle and location-specific CO2 effects. N2O emissions under elevated CO2 could not be reproduced, presumably due to a rarely considered mineralization process of organic nitrogen, which is not yet included in LandscapeDNDC.

scholarly journals Population Dynamics of Salmonella enterica within Beef Cattle Cohorts Followed from Single-Dose Metaphylactic Antibiotic Treatment until Slaughter

2019 ◽  
Vol 85 (23) ◽  
Author(s):  
Gizem Levent ◽  
Ashlynn Schlochtermeier ◽  
Samuel E. Ives ◽  
Keri N. Norman ◽  
Sara D. Lawhon ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Single Dose ◽  
Lymph Node ◽  
Beef Cattle ◽  
Salmonella Enterica ◽  
Antibiotic Use ◽  
Feeding Period ◽  
Long Term Effects ◽  
Content Type

ABSTRACT Antibiotic use in cattle can select for multidrug-resistant Salmonella enterica, which is considered a serious threat by the U.S. Centers for Disease Control and Prevention. A randomized controlled longitudinal field trial was designed to determine the long-term effects of a single dose of ceftiofur or tulathromycin on Salmonella population characteristics in cattle feces and peripheral lymph nodes and on hides. A total of 134 beef cattle from two sources were divided among 12 pens, with cattle in each of the 3-pen blocks receiving a single dose of either ceftiofur or tulathromycin or neither (control) on day 0. Fecal samples were collected before treatment (day 0) and repeatedly following treatment until slaughter (day 99+). Hide and lymph node samples were collected at slaughter age. Salmonella prevalence, phenotypic antimicrobial resistance, serotype, and phylogenetic relationships were examined. Multilevel mixed logistic regression models indicated no significant effects (P ≥ 0.218) of metaphylactic antibiotics on the prevalence of Salmonella across sample types. However, there was a significant time effect observed, with prevalence increasing from spring through the midsummer months (P < 0.0001) in feces. The majority of Salmonella isolates were pansusceptible to a panel of 14 antibiotics both before and after treatment. Highly prevalent Salmonella serotypes were Salmonella enterica serovar Montevideo, Salmonella enterica serovar Anatum, Salmonella enterica serovar Cerro, and Salmonella enterica serovar Lubbock across all sample types. Strong pen and cattle source serotype clustering effects were observed among Salmonella isolates originating from fecal, lymph node, and hide samples; however, the potential role of Salmonella isolates from the pen environment prior to animal placement was not assessed in this study. IMPORTANCE Salmonella is a leading bacterial foodborne pathogen, causing a significant number of human infections and deaths every year in the United States. Macrolides and 3rd-generation cephalosporins play critical roles in the treatment of human salmonellosis. Use of these antibiotics in beef cattle can select for resistant bacteria that may enter the food chain or spread from the farm via manure. There is a lack of longitudinal research concerning the long-term effects of metaphylactic antibiotic administration. Here, we assessed Salmonella population dynamics during the feeding period until slaughter following single-dose antibiotic treatment. We found no long-term effects of antibiotic use early in the cattle-feeding period on Salmonella prevalence and antimicrobial resistance at slaughter. We identified the pens in which cattle were housed as the factor that contributed most to Salmonella serotypes being shared; importantly, the dominant strain in each pen changed repeatedly over the entire feeding period.

Long-term Effects of Free Air CO2 Enrichment (FACE) on Soil Respiration

2006 ◽  
Vol 77 (1) ◽  
pp. 91-116 ◽  
Author(s):  
E. S. Bernhardt ◽  
J. J. Barber ◽  
J. S. Pippen ◽  
L. Taneva ◽  
J. A. Andrews ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Co2 Enrichment ◽  
Long Term Effects ◽  
Free Air Co2 Enrichment ◽  
Free Air

Long-term effects of CO2 enrichment and temperature increase on a temperate grass sward

1996 ◽  
Vol 182 (1) ◽  
pp. 101-114 ◽  
Author(s):  
J. F. Soussana ◽  
E. Casella ◽  
P. Loiseau
Keyword(s):  
Temperature Increase ◽  
Co2 Enrichment ◽  
Long Term Effects ◽  
Grass Sward

scholarly journals Strong and lasting impacts of past global warming on baleen whale and prey abundance

2018 ◽  
Author(s):  
Andrea A. Cabrera ◽  
Elena Schall ◽  
Martine Bérubé ◽  
Lutz Bachmann ◽  
Simon Berrow ◽  
...  
Keyword(s):  
Global Warming ◽  
North Atlantic Ocean ◽  
Marine Ecosystem ◽  
Marine Ecosystems ◽  
Prey Abundance ◽  
Baleen Whale ◽  
Long Term Effects ◽  
Baleen Whales ◽  
Genome Wide

AbstractThe demography of baleen whales and their prey during the past 30 thousand years was assessed to understand the effects of past rapid global warming on marine ecosystems. Mitochondrial and genome-wide DNA sequence variation in eight baleen whale and seven prey species revealed strong, ocean-wide demographic changes that were correlated with changes in global temperatures and regional oceanographic conditions. In the Southern Ocean baleen whale and prey abundance increased exponentially and in apparent synchrony, whereas changes in abundance varied among species in the more heterogeneous North Atlantic Ocean. The estimated changes in whale abundance correlated with increases in the abundance of prey likely driven by reductions in sea-ice cover and an overall increase in primary production. However, the specific regional oceanographic environment, trophic interactions and species ecology also appeared to play an important role. Somewhat surprisingly the abundance of baleen whales and prey continued to increase for several thousand years after global temperatures stabilized. These findings warn of the potential for dramatic, long-term effects of current climate changes on the marine ecosystem.One Sentence SummaryThe effects of past global warming on marine ecosystems were drastic, system-wide and long-lasting.

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