Post Midterm COPY Flashcards
whats the formula for toxic units (TU)?
TU = [exposure] / LC50 or EC50
what is the community-conditioning hypothesis?
ecological communities retain information about unique events in their history; akin to the population bottleneck theory; may account for persistence of toxicant effects long after degradation
Differentiate between observational and experimental studies
observational studies use biomonitoring, surveying, epidemiology. Experimental studies are manipulative, they change things.
these ecosystems are typically antagonistic, some synergistic
freshwater
explain the stability hypothesis for increased tropic biodiversity
tropics are more stable/predictable, species can specialize
why are aquatic systems typically more sensitive?
because they have high NPP but low biomass
in the river continuum concept, upstream is ___trophic and downstream is ____trophic
heterotrophic, autotrophic
what is QSAR
quantitative structure-activity relationship: method used to attempt to group chemicals that are structurally related by their mode of action or chemical properties using stats
what is the intermediate disturbance hypothesis?
researchers have found that exposure to intermediate disturbance or stress will maximize species diversity and stability
explain the heterogeneity hypothesis for increased tropic biodiversity
tropics are more physically complex, more habitats for specialization
Define community ecotoxicology
the study of the pollutant effects on species abundance, diversity and interactions in a common environment
What is trophic cascade
Lethal or sublethal pollutant effects on predators, grazers, or scavengers leading to cascading effects at lower trophic levels
What is the “salting out effect”?
increased salinity in water increases persistence of pesticides and POPs
What are the shannon and simpson diversity indices individually sensitive to?
shannon to rare species, simpson to dominance
These types of effects usually decrease organism abundance (indirect or direct)
Direct effects
what is dose-ratio dependent deviation
shift between synergism and antagonism dependent on ratio of mixture constituents
name four major ecosystem process that can be affected by contaminants
(1) decomposition (2) nutrient cycling (3) primary production (4) energy flow
name 5 community characteristics that can influence stability and recovery
community complexity, community maturity, community history, recolonization ability, and life history traits of community members
What is competitive release
When a pollutant resistant species wins or gains advantage. Niche overlap, interspecific competition
describe component based mixture studies
use knowledge of individual toxicities of mixture components to predict/assess combined effect
what are the 5 key features that determine severity of community resistance to disturbance?
(1) magnitude (2) frequency (3) duration (4) scale (5) timing
These types of effects usually increase or decrease abundance (indirect or direct)
Indirect effects
What are some problems associated with acidification in boreal lakes
Declines in DOC and DIC, reduced base cations, elevated dissolved metals, biota increased exposure to DNA-damaging UV-B radiation and metal toxicity, impairs biodiversity and certain processes
what is macroecology
subfield of ecology that studies relationships between organisms and their environment at large spatial and temporal scales to characterize and explain patterns of abundance, distribution and diversity
describe bottom-up mixture studies
identify most hazardous components of mixture to set thresholds; could apply uncertainty factor
Define community ecology
the study of species abundance, diversity and interaction among all populations in a common environment
what is the rivet popper hypothesis?
species are like rivets on airplanes with each species playing a small but critical role in keeping the plane/community airborne
Name 4 global scale anthropogenic contaminants
(1) Organochlorines (2) Brominated flame retardants (3) Mercury (4) Perfluorooctane suflonate (PFOS)
what is PICT?
Pollution induced community tolerance
What are the 6 factors/filters controlling community composition and biodiversity
(1) historical and evolutionary (2) biogeographical (3) dispersal ability, colonization (4) physical environment (5) species interaction (6) anthropogenic
what are the 6 leading hypotheses why amphibians are declining?
1) alien species 2) over-exploitation 3) land use change 4) global change (UV, warming) 5) increased pesticide use 6) emerging infectious disease
What are five projected consequences of the “new climate”
(1) surface temperature rise (2) heat waves more frequent, long, intense (3) extreme precipitation (4) ocean warming and acidification (5) global sea level rise
what are the pros and cons of MIXTOX?
Pro: allows for complex mixture analysis Con: complex and difficult, limited applicability in field settings
What is the most important environmental policy in Canada?
CEPA (1999) Canadian Environmental Protection Act
Define community
Communities are groups of interacting species that occur together at the same place and time and interact either directly or indirectly
what are some major contaminants found in OSPW?
naphthenic acids, PAHs, benzene, phenols, heavy metals
What is Rapaport’s Rule of environmental gradients?
species found in more variable habitats have greater tolerance than those in more benign habitats; Hypothesis that states that plant and animal ranges are generally smaller and richness is higher at lower latitude/elevations than at higher latitude/elevations
what is dose-level dependent deviation
shift between synergism and antagonism dependent on TU of mixture constituents
explain the evolutionary time hypothesis for increase tropic biodiversity
tropics are “older”, not subjected to recent glaciation, thus more time for speciation
multiple stressors in an organism can cause: (3)
1) increased contaminant exposure 2) increased susceptibility 3) reduced adaptive capacity
What are four reported consequences of climates change
(1) rising temperatures (2) increased melting/thawing (3) rising sea levels (4) increased weather severity
explain the productivity hypothesis for increased tropic biodiversity
tropics have more primary productivity, more food, greater food web complexity
Name two mechanisms of indirect pollution impacts on communities
Competitive release and trophic cascade
what is the redundancy hypothesis?
species with similar niche are considered redundant because they could be eliminated or replaced by others with no loss in community function
what are the 6 key features that determine resilience from disturbance?
(1) magnitude (2) frequency (3) duration (4) scale (5) timing (6) physical features of affected habitat
these ecosystems are typically synergistic or additive
marine
give three examples of environmental gradients
pH, elevation, temperature
on a species abundance curve, what do the y-intercept, the length of x, and m represent?
y-intercept indicates dominance, the length of x indicates richness, the m indicates evenness
