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Arctic marine environments & their environments - Coggle Diagram
Arctic marine environments & their environments
Stratification
Brines
MIxed layer
Halocline (cold and stable due to salinity gradient)
Warm water (less saline)
Environmental Constraints in Arctic Marince Ecosystems
hydrographic complexity:
Sea ice is not really ice
Types of water based on salinity
Freshwater
Brakish water
Saline water
Brine
Frazil form
thin sheets of ice (nilas)
Pancake ice
These pancakes will merge together (congelation growth)
Heat gradient is from the bottom of the sea to the surface/air
Multi year life
Oldest layers are on the top of the ice sheets. THe ice grows underneath
Arctic sea ice extent
The last ice area (LIA): Oldest and thickest ice
Melt ponds cause the arctic sea ice to melt more rapidly
Feedback loop
Landfast ice
Ice ridges
Extent: Landfast ice covers 1.8 km2 annually, with over one-third in the kara, laptev and east Siberian Seas, extending up to 300 km offshore
Landfast ice grows throughout the season, meeting sea ice around november
Slow freezing process: Freezing point in the ocean is -1,8 C.
In contrast to fresh water, the sal in ocean water causes the density of the water to increase as it nears the freezing point, sinking away from the surface as it cools
Arctic sea ice drift --> Caused by atmospheric circulation patterns: HIgh pressure system, transpolar stream, and overall the arctic oscillation
Drifting ice
Polynyans
During the growth season: Landfast ice goes northward, Ice sheets go southward
Areas of open water, or low ice concentrations, that occur in locations and/or at times when a thick layer of sea ice would otherwise be expected. Stable area of open water within the ice
Convective forcing: Oceanig heat flux
Biodiversity and primary production
3 realms of biodiversity.
Sea ice, water column (pelagic), benthos
Pelagic realm = most dynamic of the arctic marine realms
Primary producer
Zooplankton and predators
Threaths
Biodiversity in the benthic realm
Strong spatio-temporal variation in biodiversity
Seasonal biodiversity patterns
Influence of Environemental factors
Species Co-occurence
Arctic marine fauna is younger and less diverse than other oceans. Historical context: Species loss during glaciations.
Potential impacts of climate change on primary production
Earlier ice melt: phenological mismatches
Dynamics of primary production
Diatoms dominate arctic primary production, both within sea ice and in the water column
Spatial variations in productivity
Trends in primary productivity
Primarly due to shorther duration of sea ice and higher temperatures
Permafrost underlies Arctic watersheds.
much more rainfall in the permafrost areas in the future
Current trends in permafrost thawing can affect marine dynamics in various ways
LIght input in the arctic marine areas.
PAR: Photosynthetic active radiation
The range of wavelenghts in the visible specturm used by photosynthetic organisms
Solar Zenith in the arctic is after 50 degrees. Incoming light decreases almost linearly with solar zenith angle above 50 degrees.
Light is a critical driver of Arctic marine ecosystems, enabling primary production by sea ice algae and phytoplankton. These organisms form the foundation of the arctic food web.
Incoming light
Increased soot deposition
Light propagation through seawater
CDOM
SPM
Environmental protection: the arctic has the lowest level of protection of all marine areas in the world.
Arctic nations have established marine protected areas
(MPAs
) within their jurisdictions, these efforts often lack coordination, leading to gaps in protection
ArcNet: a network design framework to help achieve ocean-scale area based marine conservation in the arctic.
Non-indigenous views on sea ice
The last ice area (LIA): oldest and thickest ice
Melt ponds cause the Arctic sea ice to melt more rapidly