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Climate Change Impacts on Marine Ecosystems (Doney et al) - Coggle Diagram
Climate Change Impacts on Marine Ecosystems (Doney et al)
CLIMATE AND GLOBAL CHANGE
"Humans influence climate primarily through fossil-fuel, industrial, agricultural, and other land-use emissions that alter atmospheric composition."
"Upper-ocean heat content has grown substantially since the 1950's, with mean global sea-surface temperature (SST) increasing by approximately 0.4C"
"upper ocean salinity trending fresher in low-salinity regions and saltier in high-salinity regions, patterns consistent with a warmer atmosphere and SSTs driving elevated evaporation and precitipation rates"
"Sea-ice extent has declined dramatically in the Arctic and along the western Antarctic Peninsula," and this is leading to sea level rise
"Climate warming affects regional wind patterns and thus ocean circulation in multiple dimensions"
frequency and strength of tropical cyclones
local increases in upwelling, leading to regional cooling
projected declines in ocean oxygen levels (hypoxia) caused by low oxygen solubility at higher temps and reduced ventilation from stratification and circulation changes
ocean acidifiation as a result of increased oceanic CO2 uptake
BIOLOGICAL PROCESSES AND STRUCTURE
Physiological Response
the "principal determinant of a species' tolerance to environmental variability and change"
"as climate or other conditions shift, organisms initially respond based on physiological and behavioral adaptations molded through their evolutionary history" and either take actions such as acclimatization, adaptation, migration, or death
may benefit some species or populations
"winning" species and "losing" species
metabolic rate in ectothermic organisms rises exponentially in higher temperature
this can be assumed to hold true in warmer oceans
environmental resources like DO remain limiting factors
increases respiratory demand in heterotrophs, leaving less energy for growth
expansion and intensification of hypoxis regions along productive ocean margins has led to mass mortalities of organisms in several areas
Ocean acidification thought to increase energetic cost of calcification
Population and Community Responses
documented shifts in population range and distributions
ex: exchange of organisms between North Atlantic and North Pacific as sea ice melts
species align their distributions to match their physiological tolerances under changing environmental conditions
Climate-related shifts contribute to observed alterations in community composition and biodiversity for many systems and organism groups
alterations in trophic interactions as a result of unevenly-affected phenologies across levels
Ecosystem Structure and Function
ecosystems integrate the responses of organism physiologies and ecological interactions to changes in climate and CO2, leading to diverse mechanisms that link such changes
warmer temperatures lead to vertical stratification leads to decreases in phytoplankton and primary production
impacts of climate change on keystone and foundational species such as oysters and corals impacts entire ecosystems
altered ocean circulation may change organism dispersal, disrupting species and community dynamics
ECOSYSTEM CASE STUDIES
Ice-Dominated Polar Systems
climate of poles changing faster than anywhere on earth, making them a good bellwether and illustration of ecosystem-level consequences
sea ice deeply important
provides habitat
reduction may result in increased open water phytoplankton primary production
early ice-edge bloom supports underlying benthic communities, often intitiating reproductive processes in spring
seasonally ice covred northern bering shelf ecosystem already experiencing changes
loss of ice in Antarctica have possible led to major regime shift changes in pelagic, specifically decreased krill populations
Coral Reef Systems
Called the "canary in the coal mine" for ocean warming and acidificatoin
warming of as little as 1C causes bleaching
acidification makes it harder for corals to secrete and maintain their skeletons
Upwelling Systems: The California Current