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

Population dynamics of Cymodocea nodosa under future ocean scenarios.

10.1101/484634 ◽

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.

Download Full-text

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

10.20944/preprints202007.0574.v1 ◽

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.

Download Full-text

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

Applied and Environmental Microbiology ◽

10.1128/aem.01386-19 ◽

2019 ◽

Vol 85 (23) ◽

Cited By ~ 3

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.

Download Full-text

Long-Term Effects of Acute Low-Level X-rays on the Population Dynamics of the Yellow Fever Mosquito, Aedes Aegypti

Health Physics ◽

10.1097/00004032-196512000-00035 ◽

1965 ◽

Vol 11 (12) ◽

pp. 1577-1583 ◽

Cited By ~ 3

Author(s):

William K. Willard

Keyword(s):

Population Dynamics ◽

Aedes Aegypti ◽

Yellow Fever ◽

X Rays ◽

Yellow Fever Mosquito ◽

Long Term Effects ◽

Low Level

Download Full-text

Plant responses to volcanically elevated CO<sub>2</sub> in two Costa Rican forests

Biogeosciences ◽

10.5194/bg-16-1343-2019 ◽

2019 ◽

Vol 16 (6) ◽

pp. 1343-1360 ◽

Cited By ~ 1

Author(s):

Robert R. Bogue ◽

Florian M. Schwandner ◽

Joshua B. Fisher ◽

Ryan Pavlick ◽

Troy S. Magney ◽

...

Keyword(s):

Elevated Co2 ◽

Chlorophyll Concentration ◽

Carbon Isotopic Composition ◽

Tropical Trees ◽

Ecological Impacts ◽

Atmospheric Co2 ◽

Natural Experiments ◽

Long Term Effects ◽

Active Volcanoes

Abstract. We explore the use of active volcanoes to determine the short- and long-term effects of elevated CO2 on tropical trees. Active volcanoes continuously but variably emit CO2 through diffuse emissions on their flanks, exposing the overlying ecosystems to elevated levels of atmospheric CO2. We found tight correlations (r2=0.86 and r2=0.74) between wood stable carbon isotopic composition and co-located volcanogenic CO2 emissions for two of three investigated species (Oreopanax xalapensis and Buddleja nitida), which documents the long-term photosynthetic incorporation of isotopically heavy volcanogenic carbon into wood biomass. Measurements of leaf fluorescence and chlorophyll concentration suggest that volcanic CO2 also has measurable short-term functional impacts on select species of tropical trees. Our findings indicate significant potential for future studies to utilize ecosystems located on active volcanoes as natural experiments to examine the ecological impacts of elevated atmospheric CO2 in the tropics and elsewhere. Results also point the way toward a possible future utilization of ecosystems exposed to volcanically elevated CO2 to detect changes in deep volcanic degassing by using selected species of trees as sensors.

Download Full-text