scholarly journals Seasonal variations in environmental conditions of fresh-water ostracode habitats, San Francisco Peninsula, California

1992 ◽  
Author(s):  
Claire Carter
Keyword(s):  
Fresh Water ◽  
San Francisco ◽  
Environmental Conditions ◽  
Seasonal Variations

scholarly journals The Clever Strategies That Fishes Use to Survive in San Francisco’s Dynamic Estuary

2021 ◽  
Vol 9 ◽  
Author(s):  
Rachel A. Fichman ◽  
Adi Khen ◽  
Malte Willmes ◽  
Jonathon Kuntz ◽  
Alexander R. Scott ◽  
...  
Keyword(s):  
Fresh Water ◽  
San Francisco ◽  
Environmental Conditions ◽  
San Francisco Estuary ◽  
Salty Water ◽  
Different Parts

Estuaries are places where fresh water from rivers mixes with salty water from the ocean. Why does this matter? This mixing creates dynamic, ever-changing conditions that fishes must navigate in order to survive. Environmental conditions can change yearly, seasonally, daily, and even hourly. Fishes use many different strategies to adjust to this wild variation. Some are picky and only use certain habitats. Others use many different kinds of habitats and move between them at different times of the year. Adults and juveniles might even live away from each other in different parts of the estuary. In this article, we describe some of the clever strategies that fishes use to survive in estuaries. We also consider how scientists uncover these clever strategies and what each of us can do to help protect the fishes of the San Francisco Estuary and elsewhere.

scholarly journals Spatial and Seasonal Variations of Standardized Photosynthetic Parameters under Different Environmental Conditions for Young Planted Larix olgensis Henry Trees

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 522 ◽  
Author(s):  
Qiang Liu ◽  
Fengri Li
Keyword(s):  
Environmental Conditions ◽  
Seasonal Variations ◽  
Seasonal Pattern ◽  
Repeated Measurements ◽  
Seasonal Patterns ◽  
Photosynthetic Parameters ◽  
Relative Depth ◽  
Larix Olgensis ◽  
Vertical Variations ◽  
Larix Olgensis Henry

Understanding the spatial and seasonal variations in leaf physiology is critical for accurately modeling the carbon uptake, physiological processes and growth of entire canopies and stands. For a 17-year-old Larix olgensis Henry plantation, vertical whorl-by-whorl sampling and analyses of seasonally repeated measurements of major photosynthetic parameters were conducted, and the correlations between photosynthetic parameters and environmental conditions, leaf morphological traits and spatial position within the crown were analyzed. According to the correlations, the photosynthetic parameters were standardized based on the environmental conditions to avoid the influence of the changing environment on the patterns of spatial and seasonal variations of photosynthetic parameters. The results showed that the standardized light-saturated net photosynthetic rate (SPmax), standardized dark respiration (SRd) and standardized stomatal conductance under saturated light (Sgs-sat) were all negatively related to the relative depth into the crown (RDINC) throughout the growing season. However, their vertical patterns were different during the development of the phenological phase. In addition, different gradients of environmental conditions also influenced the values and the range of the vertical variation in photosynthesis. High temperature and low humidity usually resulted in smaller values and weaker vertical variations of SPmax and Sgs-sat, but larger values and more obvious vertical variations in SRd. SPmax and Sgs-sat usually exhibited a parabolic seasonal pattern in different vertical positions within the crown; however, SRd generally followed a concave pattern. These seasonal patterns were all weaker with increasing RDINC. Different environments also exhibited a significant influence on the seasonal patterns of photosynthesis. We suggested that standardization is necessary before analyzing spatial and seasonal variations. A single environmental condition could not represent the spatial and seasonal patterns under all gradients of the environment. Spatial and seasonal variations should be simultaneously analyzed because they are related to each other.

scholarly journals Pleistocene Branchiopods (Cladocera, Anostraca) from Transbaikalian Siberia Demonstrate Morphological and Ecological Stasis

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3063
Author(s):  
Anton A. Zharov ◽  
Anna N. Neretina ◽  
D. Christopher Rogers ◽  
Svetlana A. Reshetova ◽  
Sofia M. Sinitsa ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Seasonal Variations ◽  
Environmental Changes ◽  
Daphnia Pulex ◽  
Steppe Zone ◽  
Water Bodies ◽  
Large Branchiopods ◽  
Community Types ◽  
High Diversity

Pleistocene water bodies have been studied using the paleolimnological approach, which traces environmental changes using particular subfossils as ecological proxies, rather than analysis of the paleocommunities themselves. Within a given taphocoenosis, the presence and quantity of animals are related to environmental conditions rather than to community types where relationships between taxa are stabilized during their long-term co-occurrence and are (at least partially) more important than the particular environmental conditions at the time of deposition, which may have experienced significant seasonal and inter-seasonal variations. Here, we analyze Branchiopoda (Crustacea) of two paleolocalities in the Transbaikalian Region of Russia: Urtuy (MIS3) and Nozhiy (older than 1.5 million years). Cladocerans Daphnia (Ctenodaphnia) magna, D. (C.) similis, D. (Daphnia) pulex, Ceriodaphnia pulchella-reticulata, C. laticaudata, Simocephalus sp., Moina cf. brachiata, M. macropopa clade, Chydorus cf. sphaericus, Capmtocercus sp. and anostracans Branchinecta cf. paludosa, and Streptocephalus (Streptocephalus) sp. are found in two localities. With the exception of the last taxon, which now occurs in the southern Holarctic, all other taxa inhabit the Transbaikalian Region. Within Eurasia, the steppe zone has the greatest diversity of large branchiopods and a high diversity of some cladocerans, such as subgenus Daphnia (Ctenodaphnia) and Moina sp. Here we demonstrated that the branchiopod community in shallow steppe water bodies has been unchanged since at least the Pleistocene, demonstrating long-term morphological and ecological stasis.

Reproductive pattern of the clams, Ruditapes decussatus and R. philippinarum on intertidal flats in Brittany

1994 ◽  
Vol 74 (2) ◽  
pp. 351-366 ◽  
Author(s):  
F. Laruelle ◽  
J. Guillou ◽  
Y.M. Paulet
Keyword(s):  
Environmental Conditions ◽  
Seasonal Variations ◽  
Reproductive Activity ◽  
Condition Index ◽  
Ruditapes Philippinarum ◽  
Breeding Period ◽  
Reproductive Pattern ◽  
Ruditapes Decussatus ◽  
Oocyte Size ◽  
Maturation Stages

Since the introduction of the Manila clam Ruditapes philippinarum (Mollusca: Bivalvia) to aquaculture clam beds, this species has spread to several sites. As a result, an extensive fishery has developed around this species. Its reproductive cycle and that of a native clam species, Ruditapes decussatus (Mollusca: Bivalvia) from two Brittany sites are examined here and the seasonal variations in the condition index, the scale of maturation stages, the histology and the oocyte size-frequencies of both species are compared. The differences observed between the species and between sites were attributed to environmental conditions. Ruditapes philippinarum showed a more extended breeding period and a greater number of spawning events than R. decussatus. In the Morbihan Gulf, the reproductive activity of R. philippinarum appeared particularly great in terms of number of spawning events, and speed of maturation. For both species, synchronism was more apparent during the first maturation, while spawning, and particularly partial spawning, tended to decrease the level of synchronization.

scholarly journals Gut microbiome, enteric infections and child growth across a rural–urban gradient: protocol for the ECoMiD prospective cohort study

BMJ Open ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. e046241
Author(s):  
Gwenyth O Lee ◽  
Joseph N S Eisenberg ◽  
Jessica Uruchima ◽  
Gabriela Vasco ◽  
Shanon M Smith ◽  
...  
Keyword(s):  
Cohort Study ◽  
San Francisco ◽  
Environmental Conditions ◽  
Gut Microbiome ◽  
Child Growth ◽  
Birth Cohort Study ◽  
Institutional Review Boards ◽  
Healthy Children ◽  
Urban Gradient ◽  
Enteric Infections

IntroductionThe functional consequences of the bacterial gut microbiome for child health are not well understood. Characteristics of the early child gut microbiome may influence the course of enteric infections, and enteric infections may change the composition of the gut microbiome, all of which may have long-term implications for child growth and development.Methods and analysisWe are conducting a community-based birth cohort study to examine interactions between gut microbiome conditions and enteric infections, and how environmental conditions affect the development of the gut microbiome. We will follow 360 newborns from 3 sites along a rural–urban gradient in northern coastal Ecuador, characterising enteric infections and gut microbial communities in the children every 3 to 6 months over their first 2 years of life. We will use longitudinal regression models to assess the correlation between environmental conditions and gut microbiome diversity and presence of specific taxa, controlling for factors that are known to be associated with the gut microbiome, such as diet. From 6 to 12 months of age, we will collect weekly stool samples to compare microbiome conditions in diarrhoea stools versus stools from healthy children prior to, during and after acute enteric infections, using principal-coordinate analysis and other multivariate statistical methods.Ethics and disseminationEthics approvals have been obtained from Emory University and the Universidad San Francisco de Quito institutional review boards. The findings will be disseminated through conference presentations and peer-reviewed journals.

scholarly journals Seasonal Variations in Sedimentological Characteristics of Uppanar River Estuary, South East Coast of India

2016 ◽  
Vol 4 (1) ◽  
Author(s):  
S. Jasmine Sheeba ◽  
G. Ramesh ◽  
G. Gnanachandrasamy ◽  
T. Ramkumar ◽  
Magdalina Monica Rozaria ◽  
...  
Keyword(s):  
Fresh Water ◽  
Seasonal Variations ◽  
East Coast ◽  
River Estuary ◽  
Chemical Characteristic ◽  
Sediment Distribution ◽  
East Coast Of India ◽  
Mean Size ◽  
Depositional Systems ◽  
Physical And Chemical

<div><p><em>The estuaine environment are dynamic and they are  the intermediate zone between the marine and fresh water regions.  This makes the estuarine  region  more dynamic  in physical and chemical characteristic. These regions serves as a passage for  the continental  materials reach the marine environment.  Because of the influence of fresh water and marine water this regions the depositional systems are dynamic and complex in nature. Despite the complexity of the of the environment, the textural analsysis and interpretation of the same provides insight into the prevailing deposition environment.  The present study are carried out in the Uppar Estuary which joins with Bay of Bengal on the east coast of India. The Sedimentological analysis indicates that sediments  most of the locations the sediments are very poorly to well sorted  with mean size ranging from 1.03 to 5.97φ. The skewness value  ranged from  -0.09 to 0.48. The kurtosis varies form 0.94 to 1.54 The seasonal variations  within the station are conspicuous. This indicates the sediment distribution pattern in controlled by the  marine  as well monsoon rainfall  in this region.</em></p></div>

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