geo engineering challenges to marine biodiversity
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Geo-Engineering Challenges to Marine Biodiversity. Richard Norris; SIO-UCSD. Direct human impacts (immediate effects ) Reduce biodiveristy & resilience Both top-down and bottom-up impacts Reduce mobility in face of climate change . Human environments typically : species poor

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major challenges to marine biodiversity
Direct human impacts(immediate effects)
    • Reduce biodiveristy & resilience
    • Both top-down and bottom-up impacts
    • Reduce mobility in face of climate change
  • Human environments typically:
  • species poor
  • short food-chains homogeneous
  • disturbed
  • have imported energy and nutrients
Major challenges to Marine Biodiversity
major challenges to marine biodiversity1
Indirect human impacts(long-range impacts) due to Global change
    • Acidification
    • Stratification
    • Altered PPT patterns
    • Storm and sea-level impacts on coasts
Major challenges to Marine Biodiversity
keeping perspective
Consider the nature of impacts that would exist under a business-as-usual scenario

Partial solutions may be preferable to no solution

…But there are worries that partial solutions will sap political will to act

Keeping Perspective
three types of geo engineering
Albedo enhancement
  • Reflectors, Cloud production and Ground-based albedo enhancement
  • Land-based Carbon Sequestration
  • CO2 into oil wells, saline aquifers, Enhanced weathering
  • Ocean-based Carbon Sequestration
  • Ocean dumping of CO2, Biochar, Nutrient fertilization, Enhanced weathering
Three types of Geo-engineering
can also think about just two categories
Methods that change the chemistry of systems
  • These typically address the acidification issue as well as climate change
  • Those that do not….
  • Usually only deal with temperature
Can also think about just two categories
albedo enhancing geo engineering consequences
Common themes—no reduction of:
  • CO2absorption in ocean
    • acidification
  • environmental loading of other waste products of fossil fuel burning—NOx, SOx, trace metals (many of them heavy metals)
    • NOx already a problem in coastal water ways
  • Carbon-particulates (ash)
Albedo-enhancing Geo-engineering Consequences
reflectors in space
Changes albedo at the top of the atmosphere
  • Because these are in space, the main impacts on ecosystems come from potential changes in weather systems, ppt, land-sea contrasts, and continued acidification
  • Diminished UV may also affect composition of surface ocean phytoplankton
Reflectors in space
reflectors in space1
Impacts from changes in weather
    • Severity related to shifting ‘natural’ processes into new frequency, geographic position, or stable states.
    • Mucking around with the PDO, NAO and other multi-decadal cycles
      • e.g. Mantua et al. 1997, Bull Am, Met. Soc
    • Of course, all these happen anyway with global change.
Reflectors in space
cloud seeding with salt spray
Increasing cloudiness:
  • Changes community structure toward low-light intensity communities with potential impacts on export production;
  • Clouds may affect air-sea temperature contrast
  • Storm intensity& evaporation weakened (Mahmud 2009 Singapore J Trop. Geography)
  • Implications for nutrient exchange between thermocline and surface.
  • Create a permanent, local el-Niño?

Shepard et al. 2009

after Latham et al, 2008

Cloud Seeding with Salt Spray
some other impacts of cloud whitening
Water removal could affect:
  • Larval abundance and viability (like desalination plants)
  • Permanent installations
  • Act as giant open-ocean habitats (Fish Aggregation Devices) for highly-migratory fishes and marine mammals
Some other impacts of cloud ‘whitening’
so 2 addition to atmosphere
Acid rain
  • Sure, but the ocean is big and relatively well mixed
  • More of a problem for poorly buffered terrestrial systems
  • BUT, deposition on snow or ice could create a runoff acid pulse to coastal waters—problematic for Arctic, Antarctic…
SO2 addition to atmosphere

www.swisseduc.ch/glaciers

so 2 addition to atmosphere1
Ozone destruction
  • increases UV influence in surface ocean
    • but ocean absorbs UV efficiently
    • Experiments show some diatoms (Pseudo-nitzschia) do well in high UV waters (Mengelt & Prezelin (2005) Mar-Ecol. Prog Series)
    • UV also reduced overall phytoplankton production (Llabres & Agusti 2010 Aquatic Microb. Bio; Finkel et al. 2010; J. Plank. Res)
    • Could be a problem for seabirds, seal colonies (walrus, fir seals, elephant seals…)
SO2 addition to atmosphere
ground based albedo enhancement
These seem unlikely to have a major impact on marine communities
  • Unless they alter weather
  • Water runoff
  • Sediment and nutrient transport by wind, streams or dissolved ground water flows.
Ground-based albedo enhancement
ocean based c sequestration
Major impacts from land-based enhanced weathering:
  • Could change the flows of dissolved compounds (like bicarbonate ion) and cations into ocean water.
  • Waste streams are likely to be concentrated
    • Have many of the same impacts as saline outfall from desalination plants
  • Could offset ocean acidification
    • But this depends upon where outfall is delivered
  • Local alkalinity spikes might contribute to ‘whitings’
Ocean-based C-Sequestration
trace metals are the problem
Peridotite is not a completely benign substance
      • due to imbalances in Mg/Ca ratios
      • High concentrations of Ni, Co, Cr; low Mo
      • A “serpentine barrens” of the sea?
Trace metals are the problem

US Forest Service

enhanced weathering
Dumping effluent from enhanced weathering like other waste streams
  • Tend to produce reduced biodiversity & short food chains
Enhanced Weathering
ocean based carbon sequestration
Consumption of other bio-limiting nutrients
  • Causes Fe-fertilization to ‘rob’ downstream communities of nutrients
  • Shortening food chains
  • Changes in marine community structure depending upon type of phytoplankton production
    • increased primary production would likely shorten food chains and reduce biodiversity.
Ocean-based Carbon Sequestration
nutrient fertilization
O2consumption
  • Impacts of doubling c-flux to the sea floor on benthic communities
  • Ocean O2(Keeling et al. 2010, Ann Rev Mar. Sci; Shaffer et al. 2009 Nature Geosci)
    • Models already predict up to ~60% volume of ocean affected by ocean hypoxia in coming millennia
    • A return to the Cretaceous?
Nutrient Fertilization
ocean based carbon sequestration1
Biochar storage in the ocean
  • Potential habitat for wood-loving taxa;
    • if stored as wood or biomass has short lifecycle owing to ship worms (>> Century)
Ocean-based Carbon Sequestration

askNature.org

geo engineering final thoughts
CO2 removal either by political will or technology deals with most problems
    • CO2 dumping in ocean could be problematic if not neutralized by carbonate or buried.
  • From a biodiversity perspective, solutions that leave acidification in place are the most dangerous (e.g. albedo enhancement)
  • But, in short-term, direct human impacts are the major threat
Geo-engineering-final thoughts
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