Population Ecology of the Itertidal Anemone Actinia tenebrosa. III. Dynamics and Environmental Factors

1979 ◽  
Vol 30 (1) ◽  
pp. 41 ◽  
Author(s):  
JR Ottaway
Keyword(s):  
New Zealand ◽  
Mortality Rate ◽  
Environmental Factors ◽  
High Temperatures ◽  
Population Ecology ◽  
Benthic Invertebrates ◽  
Rocky Intertidal ◽  
Column Diameter ◽  
Juvenile Mortality ◽  
Impact Injuries

An isolated subpopulation of A. tenebrosa was studied, for three years, on the rocky intertidal coast at Kaikoura, New Zealand. The number of adults remained very stable: 94% of adults first seen in November 1973 survived until the observations were concluded. Adults died mainly from impact injuries caused by moving rocks and logs during gales. The number of juveniles in the colony fluctuated markedly from season to season, between 81 and 225 % of the number first seen. Most settlement was in the summer months, but some occurred throughout the year. The main causes of juvenile mortality were, in order of decreasing importance, failure to successfully attach leading to probable predation by benthic invertebrates, desiccation at low tides, dislodgement or crushing by grazing molluscs, impact injuries during gales, and exposure to combinations of excessive desiccation and high temperatures at low tides. Adult mortalities appeared to be independent of size. The rate of mortality of juveniles in their first 20 days after release from brooding adults is largely independent of juvenile size. After that, the mortality rate is negatively correlated with size until juveniles exceed about 15 mm column diameter: the smaller juveniles are more susceptible to both desiccation at low tide and to fatal interference from grazing molluscs.

Population ecology of the intertidal anemone Actinia tenebrosa. IV. Growth rates and longevities

1980 ◽  
Vol 31 (3) ◽  
pp. 385 ◽  
Author(s):  
JR Ottaway
Keyword(s):  
New Zealand ◽  
Population Ecology ◽  
Growth Rates ◽  
Mortality Data ◽  
Column Diameter ◽  
Growth Data ◽  
Sea Anemones ◽  
Free Living ◽  
Growth Increments ◽  
Rocky Coast

In all, 82 adults and about 600 juvenile A tenebrosa were tracked for up to 3 years These intertidal sea anemones were free-living on the rocky coast at Kaikoura, New Zealand Regular measurements of column diameters were taken for 2 years Annual growth increments were small for all sizes of A. tenebrosa observed most increments were in the range -2 to 4 mm of column diameter per year, with the smallest anemones havmg the fastest relative mean growth rates From the growth data, A tenebrosa reaches a column diameter of 40 mm in 8-66 years after settlement From mortality data, the observed adults have a predicted mean longevity of at least 50 years and a predicted maximum longevity of at least 210 years.

Population Ecology of the Intertidal Anemone Actinia tenebrosa I. Pedal Locomotion and Intraspecific Aggression

1978 ◽  
Vol 29 (6) ◽  
pp. 787 ◽  
Author(s):  
JR Ottaway
Keyword(s):  
Natural Population ◽  
Population Ecology ◽  
External Factors ◽  
Intraspecific Aggression ◽  
Column Diameter ◽  
Rock Substratum ◽  
Impact Injuries

Some 80 adult and over 250 juvenile A. tenebrosa, the total natural population on 2.5 m² of a stable rock substratum, were tracked for up to 738 days. In this period 24% of adults and 10% of juveniles moved > 250 mm, Some adults and many juveniles showed no discernible locomotion at all, although most juveniles survived less than 20 days. Large, directed movements of up to 1.6 m were sometimes associated with such external factors as impact injuries from moving rocks or logs, physical shocks, repeated desiccation, interference from molluscs, or wounding from intraspecific aggression. Acrorhagi are the nematocyst-bearing structures, present in most A. tenebrosa larger than about 10 mm column diameter, which are used in intraspecific conflicts. Some 44 % of adults were involved in fights with other adults over the 2 years of observations. None of those fights was fatal. Contact of two adult A. tenebrosa did not always result in an aggressive conflict, but after intraspecific aggression, in both field and laboratory situations, the wounded anemone moved directly away from the site of wounding.

MS prevalence in New Zealand, an ethnically and latitudinally diverse country

2010 ◽  
Vol 16 (12) ◽  
pp. 1422-1431 ◽  
Author(s):  
Bruce V Taylor ◽  
John F Pearson ◽  
Glynnis Clarke ◽  
Deborah F Mason ◽  
David A Abernethy ◽  
...  
Keyword(s):  
New Zealand ◽  
Environmental Factors ◽  
Latitudinal Gradient ◽  
Population Level ◽  
Cross Sectional Study ◽  
European Population ◽  
Multiple Sources ◽  
Cross Sectional ◽  
The North ◽  
Mcdonald Criteria

Background: The prevalence of multiple sclerosis (MS) is not uniform, with a latitudinal gradient of prevalence present in most studies. Understanding the drivers of this gradient may allow a better understanding of the environmental factors involved in MS pathogenesis. Method: The New Zealand national MS prevalence study (NZMSPS) is a cross-sectional study of people with definite MS (DMS) (McDonald criteria 2005) resident in New Zealand on census night, 7 March 2006, utilizing multiple sources of notification. Capture—recapture analysis (CRA) was used to estimate missing cases. Results: Of 2917 people with DMS identified, the crude prevalence was 72.4 per 100,000 population, and 73.1 per 100,000 when age-standardized to the European population. CRA estimated that 96.7% of cases were identified. A latitudinal gradient was seen with MS prevalence increasing three-fold from the North (35°S) to the South (48°S). The gradient was non-uniform; females with relapsing—remitting/secondary-progressive (RRMS/SPMS) disease have a gradient 11 times greater than males with primary-progressive MS ( p < 1 × 10-7). DMS was significantly less common among those of Māori ethnicity. Conclusions: This study confirms the presence of a robust latitudinal gradient of MS prevalence in New Zealand. This gradient is largely driven by European females with the RRMS/SPMS phenotype. These results indicate that the environmental factors that underlie the latitudinal gradient act differentially by gender, ethnicity and MS phenotype. A better understanding of these factors may allow more targeted MS therapies aimed at modifiable environmental triggers at the population level.

Accumulation of Mercury by Plankton and Benthic Invertebrates in Riverine Lakes of Northern Manitoba (Canada): Importance of Regionally and Seasonally Varying Environmental Factors

1988 ◽  
Vol 45 (10) ◽  
pp. 1744-1757 ◽  
Author(s):  
Togwell A. Jackson
Keyword(s):  
Organic Matter ◽  
Environmental Factors ◽  
Benthic Invertebrates ◽  
Spring Flood ◽  
Chironomid Larvae ◽  
Decomposition Of Organic Matter ◽  
Preferential Uptake ◽  
Predominant Effect ◽  
Benthic Animals ◽  
Hg Accumulation

Mercury (Hg) concentrations in plankton and benthic invertebrates from riverine lakes of northern Manitoba were generally found to be unrelated, or inversely related, to inorganic and methyl mercury levels and Hg methylation rates in their habitats but were strongly dependent on environmental factors. The relationships suggest that the uptake of Hg by these organisms was controlled largely by suspended and sedimentary Hg-binding substances such as FeOOH, MnOOH, organic matter, sulfides, and clay. The sole exception was midsummer phytoplankton, whose Hg content was a function of Hg levels in local sediments, probably because interference by suspended detritus was minimal; during the spring flood, such interference had a predominant effect. Aeration of lake water by fluvial currents probably enhances the availability of Hg to plankton by promoting decomposition of organic matter and sulfides but decreases the availability of Hg to some benthic animals by causing MnOOH precipitation. FeOOH apparently limits Hg uptake by chironomid larvae but MnOOH limits Hg uptake by oligochaetes, nematodes, and pelecypods, suggesting preferential uptake of certain forms of Hg by particular biological and mineral species. Decreases in temperature may also retard Hg uptake by benthos. Biodilution has no significant effect on Hg accumulation by benthos or plankton.

City Children’s Nature Knowledge and Contact: It Is Not Just About Biodiversity Provision

2017 ◽  
Vol 50 (10) ◽  
pp. 1145-1171 ◽  
Author(s):  
Claire Freeman ◽  
Aviva Stein ◽  
Kathryn Hand ◽  
Yolanda van Heezik
Keyword(s):  
New Zealand ◽  
Environmental Factors ◽  
Ethnic Group ◽  
Social Factors ◽  
Green Spaces ◽  
Social Connections ◽  
Relative Importance ◽  
Linear Modeling ◽  
Generalized Linear Modeling ◽  
Nature Contact

Much attention has been directed at the perceived decline in city children’s contact with nature. We used a child-centric approach to assess neighborhood nature knowledge in 187 children aged 9 to 11 years, from different socioeconomic and ethnic groups in three New Zealand cities. We evaluated the relative importance of social (independence, gender, social connections, deprivation, age) and environmental factors (biodiversity) in explaining variation in knowledge at a scale relevant to each child’s independent movements. Our biodiversity evaluation reflected the natural dimensions of the habitats where children interacted with nature. Generalized linear modeling identified ethnicity as having the strongest association with nature knowledge. Within each ethnic group, social factors were most important (independence, social connections, deprivation) except for Pākehā/NZ European children, where local biodiversity was most important. Enhancing biodiversity values of private green spaces (yards) would be effective in facilitating opportunities to experience nature, which is fundamental to supporting nature contact.

Population ecology of the Intertidal Anemone Actinia tenebrosa II Geographical distribution, synonymy, reproductive cycle and fecundity

1979 ◽  
Vol 27 (2) ◽  
pp. 273 ◽  
Author(s):  
JR Ottaway
Keyword(s):  
New Zealand ◽  
Geographical Distribution ◽  
Breeding Season ◽  
Reproductive Cycle ◽  
Population Ecology ◽  
Adult Population ◽  
Gonad Development ◽  
Reproductive Mode ◽  
The Other

Synonymy and geographical distribution of A. tenebrosa are discussed. Reproductive cycle and fecundity were examined between 1972 and 1975 inclusive at Kaikoura, New Zealand. At any one time, up to 77% of the adult population developed gonads and 20-94% of adults were brooding young. The main periods of gonad development, November-April inclusive, coincided with the warmest annual sea temperatures. Over 99.4% of brooded embryos dissected from 1851 adults were tentaculate young; the rest were planulae. It is suggested that the normal reproductive mode of the observed population is cross-fertilizing labile gonochorism, in which adults change from one sex to the other within each breeding season. Brooding adults would therefore be the maternal parents of their brooded embryos, even though subsequently the brooders would appear to be asexual or could become functional males.

The presence of synaptic and chromosome disjunction mutants in Cenchrus ciliaris (Poaceae: Paniceae)

Bothalia ◽  
1999 ◽  
Vol 29 (2) ◽  
pp. 327-334 ◽  
Author(s):  
N. C. Visser ◽  
J. J. Spies ◽  
H. J. T. Venter
Keyword(s):  
Environmental Factors ◽  
Geographical Distribution ◽  
High Temperatures ◽  
Chromosome Abnormality ◽  
Mutant Gene ◽  
Cenchrus Ciliaris ◽  
High Incidence ◽  
Low Humidity ◽  
Recessive Mutant ◽  
Chromosome Disjunction

Synaptic mutants are present in  Cenchrus ciliaris L This species, due to the presence of linear bivalents and occasion­al trivalents and quadrivalents, is an intermediate desynaptic species. In addition, geographical distribution and environmental factors, such as high temperatures and low humidity, could also have had an influence on the desynapsis observed.The disjunction of chromosomes during anaphase I was mostly abnormal in this desynaptic species. Precocious disjunction of chromosomes into chromatids occurred during anaphase I Due to the high incidence of this chromosome abnormality, a mutant gene,  'pc'  responsible for the disjunction of chromosomes, must be present. The absence of cytokinesis in one specimen indicates a recessive mutant gene,  'va' to be active in this species.

scholarly journals ‘BRCA1’ RESPONSIVENESS TOWARDS BREAST CANCER-A POPULATION-WISE PHARMACOGENOMIC ANALYSIS

2016 ◽  
Vol 8 (9) ◽  
pp. 267 ◽  
Author(s):  
Preethi M. Iyer ◽  
Sanjay Kumar P. ◽  
Karthikeyan S. ◽  
P. K Krishnan Namboori
Keyword(s):  
Breast Cancer ◽  
Risk Factors ◽  
New Zealand ◽  
Environmental Factors ◽  
Chromosome 17 ◽  
Base Pairs ◽  
Single Nucleotide ◽  
Factors Associated ◽  
Variation Database ◽  
Different Populations

<p><strong>Objective: </strong>In the present pharmacogenomic work, the genetic, epigenetic and environmental factors associated with BRCA1 induced breast cancer, cancer proneness and its variants across different populations like Indian, Netherland, Belgium, Denmark, Austrian, New Zealand, Sweden, Malaysian and Norwegian and the ‘mutation and methylation-prone’ region of BRCA1 have been computed.</p><p><strong>Methods: </strong>The global variations associated with the disease have been identified from the ‘Leiden open variation database (LOVD 3.0)’ and ‘Indian genome variation database (IGVDB)’. The variants, ‘single nucleotide polymorphisms (SNPs)’ are then characterized. The epigenetic factors associated with breast cancer have been identified from the clinical reports and further scrutinized using EpiGRAPH tool. The various contributing environmental factors responsible for the variations have been considered.</p><p><strong>Results: </strong>All the variants across different populations such as Indian, Netherland, Belgium, Denmark, Austrian, New Zealand, Sweden, Malaysian and Norwegian are found to be in a specific transcript of BRCA1 that ranges within 41,196,312-41,277,500 (81,189 base pairs) of the chromosome 17. Two ‘single nucleotide variations (SNVs)’ (5266dupC: rs397507246 and 68_69delAG: rs386833395) have been identified as risk factors in hereditary breast and ovarian cancer syndrome in the global population and 39 SNPs have been identified as pathogenic and deleterious. ‘Evolutionary history’ seems to be the most significant attribute in the predictability of methylation of BRCA1. Unhealthy dietary habits, obesity, use of unsafe cosmetics, estrogen exposure, ‘hormone replacement therapy (HRT)’, use of oral contraceptives and smoking are the major environmental risk factors associated with breast cancer incidence.</p><p><strong>Conclusion: </strong>This chromosome location (41,196,312-41,277,500 (81,189 base pairs)) can be considered as the population-specific sensitive region corresponding to BRCA1 mutation. This supports the fact that stabilization within the region can be a promising technique to control the epigenetic variants associated with the global position. The global variation in the proneness of the disease may be due to a cumulative effect of genetic, epigenetic and environmental factors subject to further experimentations with identical variations and populations. </p>

Sign in / Sign up

Export Citation Format

Share Document