Second Midterm Flashcards
(50 cards)
Paleoecology
Paleoecology (also spelt palaeoecology) uses data from fossils and subfossils to reconstruct the ecosystems of the past. It involves the study of fossil organisms and their associated remains, including their life cycle, living interactions, natural environment, and manner of death and burial to reconstruct the paleoenvironment.
limnology
the study of lakes
Paleolimnological approach
select lake>select coring site and retrieve sediment core>section and date sediment core>sub sample sediments and isolate indicator of interest>collect indicator data>analyze data
Environmental indicator examples from land atmosphere and aquatic systems?
Land: pollen, mineral particles, and insect remains
Water: diatoms, chrysophytes, and chironomids
Atmosphere: carbon particles from combustion, fly ash from coal combustion, metals and other pollutants from industry
Risk Assesment
identification and quantification of the risk resulting from a specific occurence or chemical, considering the harmful effects on individuals as well as society as a whole, of using the chemical in the amount and manner proposed and all the possible routes of exposure.
Quantification ideally needs dose effect and dose response relationships in likely target individuals or groups
Ecological Risk Assesment
application of formal framework or such model to estimate the effects of human actions on a natural resource and to interpret the significance of those effects in light of the uncertainties identified in each component of the assessment process
Analysis includs initial hazard identification, exposure and dose response assessments, and risk characterization
risk assessment vs risk management
risk assessment includes scientific data on:hazard identification, toxicity characterization, and extent of exposure
Risk management includes: information/opinions from: private citizens, industry and manufacturing, and nonprofit interest groups.
add in scientific results and measurement of probability, as wellas social political and ethical considerations, you have a policy
toxicity testing, which is more common?
short term testing at high concentrations (acute)is more common than long term testing at low concentrations(chronic)
Lowest-Observed-Effect concentration
lowest tested concentration that shows a statistically significatn difference from unexposed control group
No observed effect concentration (NOEC)
highest tested concentration not showing a statistically significant difference from an exposed control group
Critical Load
the highest total input rate of a contaminant (from deposition, fertilizers, and other sources) below which harmful effects on human health as well as on ecosystem structure ad function will not occur at the site of interest from a long term perspective, according to present knowledge
Eutrophication
The process of nutrient enrichment, increased production of organic matter, and subsequent ecosystem degradation
Heterocysts in cyanobacteria
can fix nitrogen, during times of low environmental nitrogen, one out of every ten cells or so
Cyanotoxins
diverse group of toxins-neurotoxcity, hepatoxicity, cytotoxicity, and dermatoxicity
hypoxia
oxygen depletion, related to reduced concentration of dissolved oxygen in a water body leading to stress and death in aquatic organisms
why do excess nutrients cause dead zones?
nitrogen input>phytoplankton flourish at top>dead and waste go to bottom, increased food supply for decomposers>more decomposers have increased oxygen demands>insufficient oxygen suffocates fish and shrimp at bottom>dead hypoxic zone forms at the bottom
liebeg’s limiting theory-which areas are more limited by what
Coastal-by nitrogen
freshwater-by phosphorous
how old are polar bears at weaning?
2.5 years
lifespan of polar bears
24-28 years
weight
females-up to 400kg
males-up to 800kg
What 6 things are changing in the arctic?
global warming toxic chemicals harvest patterns industrial development food web disease and parasites (very clean bears)
Sea ice decreasing rate
-13.7% per decade
current population of bears
21,000 to 25,000, but 66% decline in 40 years expected
Mortality rates-days without food
>130 3% 140 6% 150 10% 160 20% 170< 28-48%
