scholarly journals Assembly history modulates vertical root distribution in a grassland experiment

2021 ◽  
Author(s):  
Inés M. Alonso-Crespo ◽  
Emanuela W.A. Weidlich ◽  
Vicky M. Temperton ◽  
Benjamin M. Delory
Keyword(s):  
Vertical Distribution ◽  
Functional Groups ◽  
Plant Communities ◽  
Functional Group ◽  
Species Level ◽  
The Other ◽  
Priority Effects ◽  
Rooting Depth ◽  
Distribution Of Roots ◽  
The Vertical Distribution

The order of arrival of plant species during assembly can affect the structure and functioning of grassland communities. These so-called priority effects have been extensively studied aboveground, but we still do not know how they affect the vertical distribution of roots in the soil and the rooting depth of plant communities. To test this hypothesis, we manipulated the order of arrival of three plant functional groups (forbs, grasses and legumes) in a rhizobox experiment. Priority effects were created by sowing one functional group 10 days before the other two. Rhizoboxes in which all functional groups were sown simultaneously were used as controls. During the experiment, the mean rooting depth of plant communities was monitored using image analysis and a new methodological approach using deep learning (RootPainter) for root segmentation. At harvest, we measured aboveground (community and species level) and belowground (community level) biomass, and assessed the vertical distribution of the root biomass in different soil layers. At the community level, all scenarios where one functional group was sown before the other two had similar shoot and root productivity. At the species level, two forbs (Achillea millefolium and Centaurea jacea) benefited from arriving early, and one legume (Trifolium pratense) had a disadvantage when it was sown after the grasses. Priority effect treatments also affected the vertical distribution of roots. When grasses were sown first, plant communities rooted more shallowly than when forbs or legumes were sown first,. In addition, roots moved down the soil profile 24% more slowly in grasses-first communities. Our results highlight that plant functional group order of arrival in grassland communities can affect the vertical distribution of roots in the soil and this may have implications for species coexistence.

scholarly journals Driving forces of the diel distribution of phytoplankton functional groups in a shallow tropical lake (Lake Monte Alegre, Southeast Brazil)

2009 ◽  
Vol 69 (1) ◽  
pp. 75-85 ◽  
Author(s):  
LM. Rangel ◽  
LHS. Silva ◽  
MS. Arcifa ◽  
A. Perticarrari
Keyword(s):  
Vertical Distribution ◽  
Functional Groups ◽  
Rainy Season ◽  
Phytoplankton Biomass ◽  
Driving Forces ◽  
Circulation Pattern ◽  
Dry Period ◽  
Phytoplankton Functional Groups ◽  
The Vertical Distribution ◽  
Cool Dry Season

Phytoplankton vertical and diel dynamics in a small shallow lake (Lake Monte Alegre, Ribeirão Preto, state of São Paulo) were investigated in two climatological periods: July 2001 (cool-dry season) and March 2002 (warm-rainy season). Monte Alegre is a eutrophic reservoir, with a warm polymictic discontinuous circulation pattern. The lake was thermally stratified in both periods, although dissolved oxygen varied less in the cool-dry period. Phytoplankton biomass was higher in the warm-rainy season and the vertical distribution was stratified in both seasons. Flagellate groups (Lm, Y, W1 and W2) and functional groups typical of shallow eutrophic environments (J, X1 and Sn) were important throughout the study period. The lake's thermal pattern strongly influenced the vertical distribution of the phytoplankton community in both periods. Biomass, functional groups and size classes of phytoplankton also were determined by the presence of more efficient herbivores in the lake, especially during the cool-dry period when phytoplankton biomass decreased.

scholarly journals Diel dynamic of phytoplankton functional groups in a tropical water supply, Extremoz Lake, northeastern Brazil

2014 ◽  
Vol 26 (4) ◽  
pp. 356-366 ◽  
Author(s):  
Thársia da Silva Pinto ◽  
Vanessa Becker
Keyword(s):  
Vertical Distribution ◽  
Functional Groups ◽  
Northeastern Brazil ◽  
Severe Drought ◽  
Dry Period ◽  
Drought Period ◽  
Tropical Water ◽  
Phytoplankton Functional Groups ◽  
The Vertical Distribution ◽  
Dry And Rainy Seasons

AIM: This study analyzed - the diel and vertical dynamics of phytoplankton functional groups in a natural tropical lake (Extremoz Lake, northeast Brazil), to investigate and understand the driver factors of the community during a severe drought period. METHODS: Sampling of the abiotic variables and phytoplankton was performed at intervals of 6 hours over 24 hours in vertical profiles, in dry and rainy seasons (according to the historical average). The phytoplankton species were grouped according to the functional groups' approach sensu Reynolds et al. (2002). RESULTS: October/12 was considered as a dry period (18.4 mm), while March/13, due to the historical average, as a rainy season, due to the low rainfall during the study period (15.7 mm), it was called severe drought. The lake showed thermal and chemical destratification in both periods. Phytoplankton biomass was higher in the dry season and their vertical distribution was stratified in both periods. In both samplings there were less algal biomass during the night. Phytoplankton functional groups of mixed and shallow systems (S1, L0 and K) were descriptors throughout the study period with higher biomass always registered in the group S1, represented by Planktolyngbya limnetica (Cyanobacteria). CONCLUSION: The lack of seasonality observed in this study, due to prolonged drought, may have influenced the pattern of homogeneous behavior in both samplings. This pattern strongly influenced the vertical distribution of phytoplankton in the two periods, with a constancy of dominance of functional descriptors groups.

scholarly journals Seasonal variation in the vertical distribution of zone over Oakshin Gangotri, Antarctica

MAUSAM ◽  
2021 ◽  
Vol 42 (3) ◽  
pp. 275-278
Author(s):  
A.L. KOPPAR ◽  
S.C. NAGRATH
Keyword(s):  
Seasonal Variation ◽  
Vertical Distribution ◽  
Early Spring ◽  
The Other ◽  
Late Winter ◽  
Double Peak ◽  
The Vertical Distribution

Ozone soundings made from Dakshin Gangotri, Antarctica during 1987 are presented. The vertical distribution of ozone over Antarctica is characterised by a double peak profile, one around 200-150 hPa and the other around 50 hPa. During late winter-early spring the upper peak is considerably depleted. Tropospheric ozoe remains low and nearly constant throughout the year.  

Vertical distribution of forms of potassium in major soil series of Tamil Nadu

2003 ◽  
Vol 51 (3) ◽  
pp. 339-346 ◽  
Author(s):  
S. Natarajan ◽  
A. Renukadevi
Keyword(s):  
Organic Carbon ◽  
Vertical Distribution ◽  
Tamil Nadu ◽  
Water Soluble ◽  
The Other ◽  
Soil Series ◽  
Exchangeable K ◽  
The Relationship ◽  
The Vertical Distribution ◽  
Total Potassium

Fifteen major soil series at the rate of three for each soil group, namely red non-calcareous, red calcareous, black calcareous, brown calcareous and alluvial soils, were studied for the vertical distribution of different forms of potassium. The total potassium content varied from 515-5513 ppm and generally increased with depth. It was positively related with clay, silt, CaCO3, CEC and total Ca. Non-exchangeable K ranged from 340-1326 ppm and did not exhibit any uniformity in its distribution in soil profiles. The exchangeable K varied from 45-684 ppm and was positively related to organic carbon. NH4OAc-K ranged from 15-298 ppm. Soil properties like clay, silt, CaCO3 and organic matter were positively related to available K. Water-soluble K varied from 2-33 ppm and was found to decrease with the depth of the soil profile. It was positively correlated with organic carbon and negatively related to clay plus silt. Studies on the relationship between the above forms of potassium indicate that, except for total K, the other forms were closely related, indicating the possibility of predicting one from the other.

scholarly journals Seasonal variation of the crustacean fauna in the belowground and aboveground strata in a Halodule wrightii meadow of northeastern Brazil

2017 ◽  
Vol 107 (0) ◽  
Author(s):  
Kcrishna V. S. Barros ◽  
Jesser F. Souza-Filho ◽  
Ricardo J. C. Paiva ◽  
Catarina L. Araújo-Silva ◽  
Alexandre O. Almeida ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Seasonal Variation ◽  
Vertical Distribution ◽  
The Other ◽  
Northeastern Brazil ◽  
Halodule Wrightii ◽  
The Vertical Distribution

ABSTRACT The different microhabitats provided by seagrasses and the habit of the species determinate the vertical distribution of crustaceans. This study verified the influence of the seasonality on the spatial distribution of the crustacean community associated with a Halodule wrightii meadow. From April 2006 to July 2007, we performed fifteen samplings in Goiabeiras Beach, Ceará State, each with five sectioned replicates in belowground and aboveground. Cumaceans and the amphipod Hyale media (Dana, 1853) had a higher frequency, density, and dominance than the other taxa, in both strata. The community exhibited gradual changes along the study, in both the belowground and aboveground strata, but the seagrass structure was not sufficient to explain the vertical distribution of the crustacean fauna along the time.

Has zooplankton 24 hour vertical distribution pattern in Lough Derg (Ireland) been changed over the period of ∼90 years?

2011 ◽  
Vol 40 (3) ◽  
Author(s):  
Agnieszka Pociecha ◽  
Thomas McCarthy
Keyword(s):  
Vertical Distribution ◽  
Zebra Mussel ◽  
Diel Vertical Migration ◽  
Food Concentration ◽  
Species Level ◽  
Total Zooplankton ◽  
Vertical Distribution Pattern ◽  
Cladoceran Species ◽  
Zooplankton Density ◽  
The Vertical Distribution

AbstractThe vertical distribution of zooplankton was examined in Lough Derg, Ireland. Zooplankton was collected at one location every 2 m from the surface to the bottom during 24 hours at four-hour intervals. Zooplankton was identified to the species level and its density was calculated for each taxon, depth and hour. We recorded 9 rotifer, 3 copepod, and 4 cladoceran species. The highest total zooplankton density (rotifers, copepods, cladocerans, mysids and zebra mussel larvae) was recorded at 3 a.m. Rotifers preferred mainly a depth from 0 to 8 m, while copepods and cladocerans were observed within the whole water column during a 24 hour observation. It was a different pattern of diurnal migration than that Southern and Gardiner (1932) received, though they didn’t study rotifers. Probably food concentration and/or predators, or other environmental factors could influence the diel vertical migration of zooplankton from Loug Derg.

The Vertical Distribution of Ciliophora and Nematoda in the Sediments of Loch Leven, Kinross

1974 ◽  
Vol 74 ◽  
pp. 265-273
Author(s):  
Victoria M. T. Bryant ◽  
Johanna E. M. Laybourn
Keyword(s):  
Species Composition ◽  
Vertical Distribution ◽  
Sampling Period ◽  
The Other ◽  
Loch Leven ◽  
Ciliate Species ◽  
The Vertical Distribution

SynopsisThe species composition of ciliates and nematodes in the mud of Loch Leven was investigated: 59 species of Ciliophora and 14 species of Nematoda were recorded. The ciliate species composition varied widely throughout the 11-month sampling period, whereas that of the nematodes was more constant.The vertical distribution of ciliates and nematodes at four sites is described and related to the findings of other workers. Two distinct patterns of vertical distribution occurred, one typical of ciliates, the other of nematodes.

Oxygen transport in soil and the vertical distribution of roots

Soil Research ◽  
2007 ◽  
Vol 45 (2) ◽  
pp. 101 ◽  
Author(s):  
F. J. Cook ◽  
J. H. Knight ◽  
F. M. Kelliher
Keyword(s):  
Vertical Distribution ◽  
Oxygen Transport ◽  
Root Zone ◽  
Root Length Density ◽  
Pore Space ◽  
Deep Roots ◽  
Terrestrial Biomes ◽  
Distribution Of Roots ◽  
The Vertical Distribution ◽  
Different Levels

An analytical solution for steady-state oxygen transport in soils including 2 sink terms, viz roots and microbes with the corresponding vertical distribution scaling lengths forming a ratio p, showed p governed the critical air-filled porosity, θc, needed by most plants. For low temperature and p, θc was <0.1 but at higher temperatures and p = 1, θc was >0.15 m3/m3. When root length density at the surface was 104 m/m3 and p > 3, θc was 0.25 m3/m3, more than half the pore space. Few combinations of soil and climate regularly meet this condition. However, for sandy soils and seasonally warm, arid regions, the theory is consistent with observation, in that plants may have some deep roots. Critical θc values are used to formulate theoretical solutions in a forward mode, so different levels of oxygen uptake by roots may be compared to microbial activity. The proportion of respiration by plant roots increases rapidly with p up to p ≈2. Synthesis of vertical root biomass density, L [= L0 exp(–z/Zr), z is the depth positive down (m)] (m/m3), data using an exponential function to represent the distribution suggested that, on average, 70 ± 10% of fine roots in 10 terrestrial biomes were located in the upper 0.1 m of soil. Integrated over the root-zone, LT is given by the product of the function’s 2 parameters, the surface value of L, L0 (m/m3), and length scale, Zr (m). As postulated, negative correlations were obtained between L0 and Zr. For a maize (Zea mays L.) crop, significantly different distributions were measured during relatively dry and wet seasons and predicted by our model. For woody and herbaceous plants, Zr (the value determines the rate of decrease in L with depth) averaged 0.3 and 0.2 m, respectively, while the corresponding averages for Rm0 [= L0.ρr, ρr is root density (kg/m)] were 2.7 and 1.1 kg/m3.

Sign in / Sign up

Export Citation Format

Share Document