Sponges associated withSargassumspp. (Phaeophyceae: Fucales) from the south-western Gulf of California

2009 ◽  
Vol 90 (1) ◽  
pp. 193-202 ◽  
Author(s):  
E. Ávila ◽  
N.I. Blancas-Gallangos ◽  
R. Riosmena-Rodríguez ◽  
L. Paul-Chávez
Keyword(s):  
Gulf Of California ◽  
Brown Seaweed ◽  
Growth Period ◽  
Temporal Variations ◽  
Growth Patterns ◽  
Sponge Species ◽  
Preliminary Assessment ◽  
Temporal And Spatial ◽  
Abundance And Diversity ◽  
Seaweed Bed

This study constitutes a preliminary assessment of the abundance and species richness of sponges living on the brown seaweedSargassumspp. from the southern Gulf of California (Mexico). The diversity and abundance of sponges associated withSargassumwas investigated from November 2006 to November 2007. In addition, it was examined whether temporal variations in the abundance of associations were influenced by changes in size and density ofSargassumas well as environmental factors such as water temperature and salinity. Twelve sponge species (4 Haplosclerida, 3 Poecilosclerida, 4 Dictyoceratida and 1 Clathrinida) were found growing epiphytically on the lower portions ofSargassumplants and the most frequent species wereCallyspongia californicaandHaliclona turquoisia(38% and 27%, respectively). The abundance of associations showed significant temporal and spatial variations, being higher from June to November (postSargassumgrowth period), at depths from 0.5–2.5 m. The number of sponge species m−2(both epiphytic and non-epiphytic) inside the seaweed bed was 4.8 species m−2, while outside it, the absence of hard substrate for attachment severely restricted the number of sponges. These results suggest thatSargassumprovide substratum and habitat for the sponge community from this region, and that their seasonal growth patterns may influence the abundance and diversity of the associations.

scholarly journals Eye in the Sky: Using UAV Imagery of Seasonal Riverine Canopy Growth to Model Water Temperature

Hydrology ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 6 ◽  
Author(s):  
Ann Willis ◽  
Eric Holmes
Keyword(s):  
Water Temperature ◽  
Aquatic Macrophyte ◽  
Model Performance ◽  
Growth Period ◽  
Growth Patterns ◽  
Management Decisions ◽  
Temporal And Spatial Variability ◽  
Spatial Configurations ◽  
Aerial Vehicle ◽  
Temporal And Spatial

Until recently, stream temperature processes controlled by aquatic macrophyte shading (i.e., the riverine canopy) was an unrecognized phenomenon. This study aims to address the question of the temporal and spatial scale of monitoring and modeling that is needed to accurately simulate canopy-controlled thermal processes. We do this by using unmanned aerial vehicle (UAV) imagery to quantify the temporal and spatial variability of the riverine canopy and subsequently develop a relationship between its growth and time. Then we apply an existing hydrodynamic and water temperature model to test various time steps of canopy growth interpolation and explore the balance between monitoring and computational efficiencies versus model performance and utility for management decisions. The results show that riverine canopies modeled at a monthly timescale are sufficient to represent water temperature processes at a resolution necessary for reach-scale water management decisions, but not local-scale. As growth patterns were more frequently updated, negligible changes were produced by the model. Spatial configurations of the riverine canopy vary interannually; new data may need to be gathered for each growth season. However, the risks of inclement field conditions during the early growth period are a challenge for monitoring via UAVs at sites with access constraints.

scholarly journals When Density Matters: The Spatial Balance between Early and Latewood

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 818
Author(s):  
Maria Royo-Navascues ◽  
Edurne Martinez del Castillo ◽  
Roberto Serrano-Notivoli ◽  
Ernesto Tejedor ◽  
Klemen Novak ◽  
...  
Keyword(s):  
Species Distribution ◽  
Pinus Halepensis ◽  
Environmental Gradients ◽  
Temporal Variations ◽  
Western Mediterranean ◽  
Climatic Conditions ◽  
Growth Patterns ◽  
Distribution Area ◽  
Mediterranean Forests ◽  
Climatic Influence

Understanding the influence of the current climate on the distribution, composition, and carbon storage capacity of Mediterranean tree species is key to determining future pathways under a warmer and drier climate scenario. Here, we evaluated the influence of biotic and environmental factors on earlywood (EW) and latewood (LW) growth in Aleppo pine (Pinus halepensis Mill.). Our investigation was based on a dense dendrochronological network (71 sites), which covered the entire distribution area of the species in the Iberian Peninsula (around 119.652 km2), and a high-resolution climate dataset of the Western Mediterranean area. We used generalized linear-mixed models to determine the spatial and temporal variations of EW and LW across the species distribution. Our results showed an intense but differentiated climatic influence on both EW and LW growth components. The climatic influence explained significant variations across the environmental gradients in the study area, which suggested an important adaptation through phenotypic plasticity and local adaptation to varying climatic conditions. In addition, we detected a clear spatial trade-off between efficiency and safety strategy in the growth patterns across the species distribution. Additionally, in more productive areas, the trees presented a higher proportion of EW (more efficient to water transport), while, in more xeric conditions, the LW proportion increased (more safety to avoid embolisms), implying an adaptation to more frequent drought episodes and a higher capacity of carbon depletion. We therefore concluded that Mediterranean forests adapted to dryer conditions might be more efficient as carbon reservoirs than forests growing in wetter areas. Finally, we advocated for the need to consider wood density (EW/LW proportion) when modeling current and future forest carbon sequestrations.

scholarly journals Simulating Spatiotemporal Dynamics of Sichuan Grassland Net Primary Productivity Using the CASA Model and In Situ Observations

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Chuanjiang Tang ◽  
Xinyu Fu ◽  
Dong Jiang ◽  
Jingying Fu ◽  
Xinyue Zhang ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Alpine Meadow ◽  
Growth Period ◽  
Temporal Variations ◽  
Light Use Efficiency ◽  
Important Indicator ◽  
Casa Model ◽  
Use Efficiency

Net primary productivity (NPP) is an important indicator for grassland resource management and sustainable development. In this paper, the NPP of Sichuan grasslands was estimated by the Carnegie-Ames-Stanford Approach (CASA) model. The results were validated with in situ data. The overall precision reached 70%; alpine meadow had the highest precision at greater than 75%, among the three types of grasslands validated. The spatial and temporal variations of Sichuan grasslands were analyzed. The absorbed photosynthetic active radiation (APAR), light use efficiency (ε), and NPP of Sichuan grasslands peaked in August, which was a vigorous growth period during 2011. High values of APAR existed in the southwest regions in altitudes from 2000 m to 4000 m. Light use efficiency (ε) varied in the different types of grasslands. The Sichuan grassland NPP was mainly distributed in the region of 3000–5000 m altitude. The NPP of alpine meadow accounted for 50% of the total NPP of Sichuan grasslands.

scholarly journals RECORDS OF Sauromalus ater (DUMÉRIL, 1856) HATCHLINGS AND SUBADULTS ON SAN FRANCISCO ISLAND, GULF OF CALIFORNIA, MÉXICO

2019 ◽  
Vol 2 (2) ◽  
pp. 15
Author(s):  
Adrián Cerdá-Ardura
Keyword(s):  
San Francisco ◽  
Sonoran Desert ◽  
Gulf Of California ◽  
Baja California ◽  
Small Island ◽  
Athene Cunicularia ◽  
Burrowing Owl ◽  
Important Sign ◽  
The Common ◽  
Abundance And Diversity

Six hatchlings of the Common or Sonoran Desert Chuckwalla (Sauromalus ater) ranging from 60 mm to 93 mm (SVL) as well as 10 subadult individuals (mostly ♀) ranging from 110 mm to 146 mm (SVL) were recorded during three casual walks on the small island San Francisco, Baja California Sur, Gulf of California, México, in January and February, 2019. The presence of these hatchlings and subadult females could be an important sign of chuckwallas’ recovery and of continued population’s recruitment following eradication of feral cats and goats from the island in 1999 and 2000 respectively, and despite the intense presence of humans (fishermen and tourists) on the island. The chuckwalla population seems to be growing and becoming conspicuous on San Francisco after almost two decades of rare and infrequent records of individuals. Also, the vegetation shows more abundance and diversity, and more extensive covering than in previous years. Other vertebrate species, like the Baja California Rattlesnake (Crotalus enyo) and the Burrowing Owl (Athene cunicularia) were recorded as well during the walks. All these observations possibly indicate a whole and progressive biota restoration on this tiny island after devastation by invasive fauna, combined with previous good wet years.

scholarly journals Análisis de crecimiento de tres especies de Caesalpinia (Leguminosae) de la selva baja caducifolia de Chamela, Jalisco

2017 ◽  
pp. 5
Author(s):  
Emmanuel Rincón ◽  
Pilar Huante ◽  
Mariana Álvarez-Añorve
Keyword(s):  
Leaf Area ◽  
Biomass Allocation ◽  
Deciduous Forest ◽  
Growth Period ◽  
Growth Patterns ◽  
Tropical Deciduous Forest ◽  
Total Biomass ◽  
Allocation Pattern ◽  
Location Patterns ◽  
Net Assimilation

The objective of this study is to assess the biomass allocation pattern s and growth characteristics of three species of Caesalpinia (Leguminosae) from the highly diverse and seasonal Chamela tropical deciduous forest , where the plant growth period is restricted to the rainy season. The studied species, although they are phylogenetically related, presented different biomass al location patterns and RGR during growth, in order to carry out a differential exploitation of resources and to promote their coexistence. There were differences in relative growth rate (RGR), root to shoot ratio (R/ S), net assimilation rate (E), biomass allocation patterns and total biomass and leaf area attained among the studied species. Caesalpinia eriostachys and C. platyloba showed similar growth patterns between them but contrasting with those of C. sclerocarpa. This suggests a temporal uncuopling of their maximum resource demand. RGR was determined to a greater extent by parameters related with E than by parameters related with the specific leaf area (SLA).

Temporal and Spatial Abundance of Acanthaster cf. Solaris (Echinodermata: Asteroidea) in a National Park in the Gulf of California, Mexico: 2005–2016

2021 ◽  
Vol 74 (3) ◽  
Author(s):  
Jenny Carolina Rodríguez-Villalobos ◽  
Carlos Hernández-Carreón ◽  
Héctor Reyes-Bonilla ◽  
Bárbara Rojas-Montiel ◽  
Amy Hudson Weaver
Keyword(s):  
Gulf Of California ◽  
National Park ◽  
Temporal And Spatial

scholarly journals Temporal and spatial variations in freeze warnings in the conterminous United States: 2005–2018

2019 ◽  
Vol 139 (3-4) ◽  
pp. 1379-1384
Author(s):  
Brandon Lawhorn ◽  
Robert C. Balling
Keyword(s):  
United States ◽  
Temporal Trends ◽  
The United States ◽  
Temporal Variations ◽  
Atmospheric Composition ◽  
Southeastern Us ◽  
The Us ◽  
Temporal And Spatial ◽  
Frost Free Period ◽  
Spatial And Temporal Trends

AbstractIt is well-documented that the United States (US), along with other mid-latitude land locations, has experienced warming in recent decades in response to changes in atmospheric composition. Among other changes, Easterling (2002) reported that the frost-free period is now longer across much of the US with the first frost in fall occurring later and the last freeze in spring occurring earlier. In this investigation, we explore spatial and temporal variations in all freeze warnings issued by the US National Weather Service. Freeze warning counts are highest in the southeastern US peaking overall in the spring and fall months. Freeze warnings tend to occur more toward summer moving northward and westward into more northerly states. Consistent with the warming in recent decades, we find statistically significant northward movements in freeze warning centroids in some months (December, February) across the study period (2005–2018). Detection of spatial and temporal trends in freeze warnings may be of interest to any number of scientists with applied climatological interests.

scholarly journals Analysis of temporal and spatial variability of atmospheric CO<sub>2</sub> concentration within Paris from the GreenLITE™ laser imaging experiment

2019 ◽  
Vol 19 (22) ◽  
pp. 13809-13825 ◽  
Author(s):  
Jinghui Lian ◽  
François-Marie Bréon ◽  
Grégoire Broquet ◽  
T. Scott Zaccheo ◽  
Jeremy Dobler ◽  
...  
Keyword(s):  
Urban Canopy ◽  
Temporal Variations ◽  
Horizontal Resolution ◽  
Atmospheric Co2 ◽  
Laser Imaging ◽  
Near Surface ◽  
Co2 Concentrations ◽  
Temporal And Spatial ◽  
The City

Abstract. In 2015, the Greenhouse gas Laser Imaging Tomography Experiment (GreenLITE™) measurement system was deployed for a long-duration experiment in the center of Paris, France. The system measures near-surface atmospheric CO2 concentrations integrated along 30 horizontal chords ranging in length from 2.3 to 5.2 km and covering an area of 25 km2 over the complex urban environment. In this study, we use this observing system together with six conventional in situ point measurements and the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and two urban canopy schemes (Urban Canopy Model – UCM; Building Effect Parameterization – BEP) at a horizontal resolution of 1 km to analyze the temporal and spatial variations in CO2 concentrations within the city of Paris and its vicinity for the 1-year period spanning December 2015 to November 2016. Such an analysis aims at supporting the development of CO2 atmospheric inversion systems at the city scale. Results show that both urban canopy schemes in the WRF-Chem model are capable of reproducing the seasonal cycle and most of the synoptic variations in the atmospheric CO2 point measurements over the suburban areas as well as the general corresponding spatial differences in CO2 concentration that span the urban area. However, within the city, there are larger discrepancies between the observations and the model results with very distinct features during winter and summer. During winter, the GreenLITE™ measurements clearly demonstrate that one urban canopy scheme (BEP) provides a much better description of temporal variations and horizontal differences in CO2 concentrations than the other (UCM) does. During summer, much larger CO2 horizontal differences are indicated by the GreenLITE™ system than both the in situ measurements and the model results, with systematic east–west variations.

scholarly journals Linking dynamical complexities from activation signals to transcription responses

2019 ◽  
Vol 6 (3) ◽  
pp. 190286
Author(s):  
Genghong Lin ◽  
Feng Jiao ◽  
Qiwen Sun ◽  
Moxun Tang ◽  
Jianshe Yu ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Growth Patterns ◽  
Carcinoma Cells ◽  
Genetic Circuit ◽  
High Frequencies ◽  
The Mean ◽  
Multiple Promoter ◽  
Activation Rates ◽  
Inducible Genes ◽  
State Selection

The transcription of inducible genes involves signalling pathways that induce DNA binding of the downstream transcription factors to form functional promoter states. How the transcription dynamics is linked to the temporal variations of activation signals is far from being fully understood. In this work, we develop a mathematical model with multiple promoter states to address this question. Each promoter state has its own activation and inactivation rates and is selected randomly with a probability that may change in time. Under the activation of constant signals, our analysis shows that if only the activation rates differ among the promoter states, then the mean transcription level m ( t ) displays only a monotone or monophasic growth pattern. In a sharp contrast, if the inactivation rates change with the promoter states, then m ( t ) may display multiphasic growth patterns. Upon the activation of signals that oscillate periodically, m ( t ) also oscillates later, almost periodically at the same frequency, but the magnitude decreases with frequency and is almost completely attenuated at high frequencies. This gives a surprising indication that multiple promoter states could filter out the signal oscillation and the noise in the random promoter state selection, as observed in the transcription of a gene activated by p53 in breast carcinoma cells. Our approach may help develop a theoretical framework to integrate coherently the genetic circuit with the promoter states to elucidate the linkage from the activation signal to the temporal profile of transcription outputs.

scholarly journals Analysis of temporal and spatial variability of atmospheric CO<sub>2</sub> concentration within Paris from the GreenLITE<sup>TM</sup> laser imaging experiment

2019 ◽  
Author(s):  
Jinghui Lian ◽  
François-Marie Bréon ◽  
Grégoire Broquet ◽  
T. Scott Zaccheo ◽  
Jeremy Dobler ◽  
...  
Keyword(s):  
Urban Canopy ◽  
Temporal Variations ◽  
Horizontal Resolution ◽  
Atmospheric Co2 ◽  
Laser Imaging ◽  
Near Surface ◽  
Co2 Concentrations ◽  
Temporal And Spatial ◽  
The City

Abstract. In 2015, the Greenhouse gas Laser Imaging Tomography Experiment (GreenLITETM) measurement system was deployed for a long-duration experiment in the center of Paris, France. The system measures near-surface atmospheric CO2 concentrations integrated along 30 horizontal chords ranging in length from 2.3 km to 5.2 km and covering an area of 25 km2 over the complex urban environment. In this study, we use this observing system together with six conventional in-situ point measurements and the WRF-Chem model coupled with two urban canopy schemes (UCM, BEP) at a horizontal resolution of 1 km to analyze the temporal and spatial variations of CO2 concentrations within the Paris city and its vicinity for the 1-year period spanning December 2015 to November 2016. Such an analysis aims at supporting the development of CO2 atmospheric inversion systems at the city scale. Results show that both urban canopy schemes in the WRF-Chem model are capable of reproducing the seasonal cycle and most of the synoptic variations in the atmospheric CO2 point measurements over the suburban areas, as well as the general corresponding spatial differences in CO2 concentration that span the urban area. However, within the city, there are larger discrepancies between the observations and the model results with very distinct features during winter and summer. During winter, the GreenLITETM measurements clearly demonstrate that one urban canopy scheme (BEP) provides a much better description of temporal variations and horizontal differences in CO2 concentrations than the other (UCM) does. During summer, much larger CO2 horizontal differences are indicated by the GreenLITETM system than both the in-situ measurements and the model results, with systematic east-west variations.

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