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

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

Ground-based albedo enhancement

Ocean based c sequestration

  • M communities ajor 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 communities 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

Enhanced Weathering

Ocean based carbon sequestration

  • C streamsonsumption 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

  • O streams2consumption

  • 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 streams 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

Geo engineering final thoughts

  • CO streams2 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