Lecture 20 Flashcards
(38 cards)
1
Q
where is climate change occurring most quickly and what impacts is it having?
A
- occurring fastest in the polar regions (~4x faster than the global average)
- leading to accelerating declines in average annual sea ice concentration, extent, and thickness
- increased air temperatures and reduced sea ice are influencing other environmental factors, including sea surface temperature and primary productivity
2
Q
how is climate change altering contaminant pathways in arctic food webs?
A
- changes in sea surface temperature and primary productivity are leading to alterations in arctic marine food webs
- northward expansion of southern species is changing energetic pathways in food webs
- altered food web structure is affecting the trophic transfer of contaminants
3
Q
what processes does climate change impact?
A
- global climate change affects physical, biological, and ecological processes
- therefore, climate change has the potential to influence the uptake and fate of POPs and contaminants of emerging arctic concern in biota and food webs through multiple mechanisms
4
Q
what are 5 physical processes being altered by climate change?
A
1) temperature
2) sea ice extent, thickness, age
3) length of the ice season
4) presence of glaciers
5) permafrost
5
Q
how are biological and ecological processes shifting with climate change?
A
- increased primary production
- reduced population sizes of some ice-dependent species
- northward range shifts of sub-arctic and temperate marine and terrestrial species
- altered trophic structuring can influence POP dynamics in arctic food webs
6
Q
what interacting factors are affecting arctic ecosystems and how are they affecting them?
A
the bioavailability, uptake, bioaccumulation, and fate of POPs are affected by:
- environmental conditions (temperature, precipitation, presence of sea ice)
- POP physicochemical properties (hydrophobicity, recalcitrance)
- biological factors (energy allocation, lipid dynamics, reproductive strategy, body size, age, etc)
7
Q
what is climate change projected to do to the impacted processes?
A
- projected to concurrently alter many of these processes and factors, potentially resulting in decreased or increased contaminant exposure at the base of the food web and changes to food web accumulation
- future state stays the same as current state at lower trophic levels but increases or decreases at higher trophic levels: no changes in abiotic exposure, changes in food web properties and interactions
- future state higher or lower than current state for all trophic levels: changes in abiotic exposure, no changes in food web properties and interactions
- future state starts lower or higher at lower trophic levels and then switches at higher trophic levels (looks like an x): changes in both abiotic exposure and food web properties and interactions
8
Q
what is temperature in terms of climate change?
A
- main abiotic driver in the environment that regulates and limits biological processes
- plays a key role in contaminant dynamics and biological and physiological processes
9
Q
what is the association with temperature and contaminant uptake and elimination?
A
- air and ocean temperatures are increasing due to climate change and are expected to continue to increase
- research on the relationship between temperature and POP uptake and elimination rates in arctic biota is limited
- contaminant uptake and elimination rates are expected to increase due to increases in metabolism
- these changes may be limited by species-specific biotransformation capacities related to physiological differences and variations in life history strategies
10
Q
what is the association of temperature and bioavailability?
A
- warmer air temperatures can increase mobilization and long-range transport of POPs from primary emissions
- increased temperature increases remobilization from secondary sources - soil, melting permafrost, seawater, glacial ice, and sea ice
- this remobilization would result in a change from contaminant sinks to contaminant sources
- Ex. long term PCB air trends show an increase of PCBs in air measured across the arctic after year 2000 which may be linked to the re-emission of PCBs from secondary sources in response to higher temperatures
11
Q
what’s the relationship between contaminants and climate patterns?
A
- large scale climate patterns (atmospheric circulation, oceanic currents, wind and precipitation patterns), along with local and regional weather, influence the long range transport of POPs
- associations have been found between the arctic oscillation and north atlantic oscillation indices and changes in contaminants in arctic studies
- modeling and correlative studies suggest that climate change affects the uptake and accumulation of POPs in arctic wildlife through altered wind and precipitation impacts on contaminant transport or wet deposition
12
Q
what were the correlations documented between the AO or NAO and contaminant trends in glaucous gulls in the norwegian arctic and ringed seals in the greenlandic and canadian arctic?
A
- findings indicate the POP levels were higher in gulls and seals following years with greater transport of air masses from north america and europe toward the arctic
- negative relationships between POPs and AO in the winter were also found in gulls and were related to changes in diet or overwintering areas
- the cold winters associated with a negative AO phase may decrease the availability of high trophic level prey during the following summer; and/or
- cold winters may force glaucous gulls to migrate further south, exposing them to higher levels of POPs
13
Q
what are the predicted impacts of climate-related increases in precipitation?
A
- climate related increases in precipitation were predicted to increase the deposition of POPs through scavenging
- years of higher rainfall were followed by years with thick-billed murre eggs having higher concentrations of OCPs and PCBs
14
Q
what is the association of contaminants and the movement of water masses?
A
- changes in the movement of water masses (eg. oceanic currents) can also influence contaminant transport to and within the arctic, and affect exposure to biota
- increased influx of warm, saline atlantic water into the european arctic will likely increase oceanic contaminant transport into the high arctic
- passive samplers deployed at different depths in the Fram Strait showed a net influx of PCBs each year from the atlantic to the arctic, and a net export of HCB and HCH from the arctic into the atlantic ocean
15
Q
what is the association between contaminants and sea ice?
A
- several studies have shown relationships between sea ice parameters and POP concentrations in marine mammals
- studies on ringed seals from several areas of the canadian arctic have reported relationships between PCBs and/or OCPs and sea ice coverage
- results mostly suggest that these POPs accumulate in ringed seals to a higher extent in years with greater total sea ice coverage
- this could be related to the ability of sea ice to deliver organic contaminants to arctic marine food webs, as sea ice, along with snowpack and glaciers, are reservoirs for organic contaminants
- re-mobilization of contaminants from sea ice and water reservoirs is increasing due to increasing temperatures and decline of sea ice
- higher levels of POPs have also been associated with shorter sea ice seasons in certain populations of ringed seals, possibly due to variations in feeding opportunities
16
Q
how does climate change impact terrestrial runoff to surface waters?
A
- Climate change is expected to increase the amount of precipitation received in the form of rain. This change will increase the runoff of terrestrial-derived organic material from land to surface waters
- Darkened coastal waters due to terrestrial input might further alter predator-prey relationships by decreasing the hunting efficiency of optical predators, such as fish, in favour of tactile predators, such as jelly fish
- Snow melt releases contaminants recently deposited from the atmosphere, whereas glacial melt transfers contaminants stored over the long-term to the terrestrial system, coastal waters, and lake sediments
17
Q
what are the impacts of the thawing of permafrost?
A
- Industrial developments in the Arctic assumed that permafrost would serve as a permanent and stable platform and that perennially frozen ground would function as long-term containment for solid and liquid industrial waste due to its properties as a hydrological barrier
- These widespread practices across the Arctic led to the accumulation of various toxic substances on or in permafrost
- Known industrial waste types include drilling and mining wastes, toxic substances like drilling muds and fluids, mine waste heaps, metals, spilled fuels, and radioactive waste have the potential to be mobilized with permafrost thawing
18
Q
how does climate change impact primary productivity and benthos?
A
- Climate change is expected to affect both the seasonal timing of primary productivity and the amount (i.e., biomass) of primary production
- This in turn can affect the bioavailability of POPs entering the base of the food web
- Increased primary production leads to more particulate matter and particle bound POPs
- POPs subjected to sedimentation into the benthic systems could increase, which all else being equal, would result in higher POP exposure in benthic ecosystems through benthopelagic coupling
19
Q
how are species interactions impacted by climate change?
A
- species are undergoing a global redistribution towards cooler regions, including the Arctic and Antarctic, higher altitudes, and increased water depths
- These movements are occurring to 1) maintain thermal tolerances and 2) in response to other species for example predators following their prey
- These changes are predicted to be greatest in polar regions
- Northern boundary is shifting – borealization
- Leading to a shift in community composition and predator-prey interactions
20
Q
how do contaminant concentrations and distributions differ in native and non-native species?
A
- Capelin and sand lance had relatively higher concentrations that were attributed to these fish acquiring temperate contaminants during their
seasonal migrations - These species may have the potential to act as vectors of contaminants into the Arctic
21
Q
how do contaminant concentrations differ in transient vs. resident species?
A
- Transient marine fish and mammals showed higher POP concentrations than similar trophic-position Arctic resident species
22
Q
how has climate change impacted the diet of polar bears?
A
- Polar bears have shifted towards feeding on more sub-Arctic prey species
- Changes in contaminant trends in polar bears in the Canadian Arctic were attributed to changes in the proportion of bearded seal, sub-Arctic harbour seal, and harp seal in their diet
23
Q
how have the diets of East Greenland polar bears shifted?
A
polar bears shifted towards feeding on subArctic hooded seal and harp seal, which was associated with
NAO conditions – an increase in POPs was been found and could be due to hooded and harp seals 1) occupying a higher trophic level than ringed seals; and / or 2) act as biovectors transporting contaminants from southern regions
24
Q
how have the diets of Southern Beaufort Sea polar bears shifted?
A
some polar bears spend extended periods of time onshore during the reduced ice season and consume onshore foods, namely the remains of subsistence harvested bowhead whale which occupy a lower trophic level than their preferred prey ringed seals. These polar bears had lower concentrations of certain OCPs.
25
what are the lipid dynamics and energy allocation at the base of the arctic food web?
the lipid mass is predicted to decrease with an
increase of southern copepod species, and reduced
influence of the larger, lipid-rich Arctic species
26
what are the lipid dynamics and energy allocation at the top of the arctic food web?
- undergo seasonal changes in body fatness due to fasting periods, these periods may change in response to a changing climate
- in seasons and areas with reduced sea ice extent, polar bears have been found to be thinner and consequently had higher tissue concentrations of POPs
27
what are the lipid dynamics and energy allocation at the ecosystem level?
the overall lipid mass is expected to increase due to a more rapid turnover of copepods and a higher general biomass of zooplankton
28
what are the projected effects of borealization on Arctic marine zooplankton?
decreased body size, decreased lipid per individual, increased biovectors, many outcomes unknown
29
what are the behavioural changes related to sea ice cover?
- Climate change alters the behavior of Arctic marine mammals reliant on ice, which is connected to their diet, physiology, endocrine function, and ultimately exposures to, and effects of, contaminants
- Changes in the sea ice habitat of polar bears have forced them to spend longer portions of the year in lower quality habitats with reduced access to high-quality prey or to move longer distances with greater energy expenditure
- Polar bears in the Barents Sea, showed that offshore polar bears were exposed to higher concentrations of POPs than coastal bears and that this was related to
differences in feeding habits, energy expenditure, and geographical distribution
- offshore bears were however fatter than coastal ones therefore plasma concentrations of lipophilic POPs did not differ
- proteinophilic PFASs were higher in pelagic bears as this contaminant is less affected by changes in lipid
30
Climate change and contaminants are likely to interact with other environmental and health stressors –
lessen, enhance or produce unexpected impacts:
- environmental stressors: ocean acidification, presence of plastics, harmful algal blooms, habitat destruction
- social, economic, and political factors: human migration, resource exploration and extraction, increased ship traffic
31
how does climate change impact disease and immunity?
- New infectious diseases, changes in pathogen distribution, and an increasing presence of zoonotic pathogens are likely to occur with climate change
- Physiological stress induced by increased temperature might impair the immune system in cold blooded organisms such as fish, rendering them more susceptible to infection and disease
- POPs are known to suppress immunity
32
how might climate change affect an individual’s
sensitivity to contaminants?
- Altering the toxicokinetics (i.e., uptake, distribution, metabolism, and elimination of toxicants)
- Altering toxicodynamics (i.e., how contaminants affect biological systems over time, toxicant interactions with biological receptors and enzymes)
33
what research tools are used to assess ecosystem health?
- Risk quotient analyses, which assess links between contaminant exposures and various endocrine, reproductive or immune system effects could be used
- Omics approaches, steroid hormones, vitamin levels, immunotoxicity endpoints
- Lipid measurements – classes
- Controlled laboratory studies – cell line assays
34
why were arctic char and ringed seals used in a study to identify contaminant and climate change related effects?
- Widespread, circumpolar distribution
- Sensitive to environment change
- Important role in marine food webs
- Dietary and cultural importance to Inuit
35
what were the results of a study used to identify contaminant and climate change related effects?
- Stable isotopic ratios of nitrogen and sulfur suggest that Arctic char shifted to feeding at higher trophic levels and on more marine resources
- Changes in diet for Arctic char and a decline in their condition was linked to a change sea ice conditions and Chl A
- Arctic char trophic position was higher in years with low chlorophyll concentrations and when it takes longer for sea ice to break up
- Feeding at higher trophic levels and on more marine resources may explain increasing Hg trends
- Arctic char Hg was higher in years where sea ice was unstable during the spring and when primary productivity was low
- Ringed seals have shifted to feeding at higher trophic levels and more pelagically
36
what was the optimal tissue to characterize the effects of contaminant and climate-related stresstors?
- Metabolite profiles in plasma and liver were more suitable for studying changes in diet
- Liver and blubber were more suitable for studying the impacts of contaminants
37
what are the preliminary findings for studies in Nunasiavut?
- Changing environmental conditions have altered the feeding ecology of Arctic char and ringed seals
- Changing environmental conditions have contributed to higher mercury concentrations in Arctic char
- PCBs and environmental variables are altering gene transcripts and metabolites in Nunatsiavut ringed seals
38
what are the knowledge gaps and future needs related to climate change and contaminants?
- a broad range of habitats/regions, species/trophic levels, and processes must be considered for a comprehensive understanding and interpretation of the consequences to the distribution, accumulation, and effects of contaminants
- long-term pan-Arctic monitoring that includes environmental variables / climate related parameters, ecology, physiology, behaviour, and contaminant data
