benefits and impacts for the marine environment due to the
TRANSCRIPT
Benefits and impacts for the marine environment due to the pH changes
Caterina Lanfredi / Valentina De Santis / Arianna Azzellino
[email protected] / [email protected] /
DESARC - MARESANUS
DEcreasing Seawater Acidification Removing Carbon
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Approximately 1/3 of the atmospheric CO2 is absorbed by the oceans, where it is transformed into carbonic acid, which rapidly dissociates into bicarbonate, carbonate and H+ ions, resulting in an increase of acidity of the sea waters and altering marine ecosystems.
More CO2 into the atmosphere→Higher concentration of H+ ions into the sea→ Lower pH value
ACIDIFICATION PROCESS
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ACIDIFICATION PROCESS
La rimozione di CO2 dall’atmosfera e il progetto Desarc-Maresanus. 4-5 febbraio, 2020
ACIDIFICATION PROCESS
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ACIDIFICATION PROCESS
Laboratory experiments show that calcification rates of many marine calcifyers, like certain corals, foraminifera, coccolithophores and shellfish, reduce under more acidic (high CO2) conditions.
Confidence levels (IPCC)
EFFECTS OF ACIDIFICATION
Turley et al., 2006
Rapid ocean acidification
EFFECTS OF ACIDIFICATION
Jason Hall-Spencer
EFFECTS OF ACIDIFICATION
EFFECTS OF ACIDIFICATION
iStockphoto.com/Eduardo Luzzatti
EFFECTS OF ACIDIFICATION
Coral Reefs
iStockphoto.com/t.light
EFFECTS OF ACIDIFICATION
Changes in marine ecosystems
iStockphoto.com/Richard Carey
EFFECTS OF ACIDIFICATION
Calcifying organisms
Ulf Riebesell; GEOMAR
EFFECTS OF ACIDIFICATION
Marine snails
Steve Ringman
EFFECTS OF ACIDIFICATION
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Species directly affected by acidification
Species indirectly affected by acidification
The marine food web is highly interconnected. While some species like shelled organisms are directly affected by ocean acidification, other species are affected indirectly because they eat shelled organisms or live in habitats they created.
EFFECTS OF ACIDIFICATION
Nitrogen fixation stimulated
NASA's Goddard Space Flight Center/USGS)
EFFECTS OF ACIDIFICATION
Economic losses
iStockphoto.com/Thomas Bradford
EFFECTS OF ACIDIFICATION
Commercially important organismsEFFECTS OF ACIDIFICATION
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pH CHANGES IN THE MARINE ENVIRONMENT
Most of the literature on the biological response to changes in seawatercarbonate chemistry has focused on acidifying condition.
The problem of ocean acidification
affects also the Mediterranean Sea
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pH CHANGES IN THE MARINE ENVIRONMENT
The problem of ocean acidification
affects also the Mediterranean Sea
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pH CHANGES IN THE MARINE ENVIRONMENT
The problem of ocean acidification
affects also the Mediterranean Sea
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pH CHANGES IN THE MARINE ENVIRONMENT
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EFFECTS OF ALKALINIZATION
The potential environmental effects and the magnitude of the ocean limingimpact depend on different factors such as the following:
• the variation in the pH level generated at the deployment site;• the deployment depth (m)• the applied spatial scale: local (localized in the vicinity of the ship; along the
ship route; the volume of water moved by the ship) regional?• the applied temporal scale: short-term (hours to days) long-term (months to
years)• the ecosystems involved (coastal or pelagic)
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EFFECTS OF ALKALINIZATION
The variation of ocean alkalinity influences the saturation state of carbonate minerals that are essentials for marine carbonate-producing organisms, such as reefs populated with benthic species (coral shellfish and green macroalgae) and the pelagic ecosystems (e.g., components of planktonic ecosystem such as coccolithophores, foraminifera, pteropods/heteropods).
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EFFECTS OF ALKALINIZATION: Benthonic species
The marine biota relies on pH to regulate ion transport;
The energy they invest to maintain intra- and extra-cellular pH depends on ambient pH.
Experimental studies reveal that the increase of alkalinity could disrupt the acid-base balance of marine organisms (i.e. Carcinus meanas).
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Ophioderma longicauda Lithophyllum stictaeformePorites porites
EFFECTS OF ALKALINIZATION: Benthonic species
Marine calcifies which mediate calcification by providing nucleation sites on abiological template (e.g. corals, shellfish, crustacean) are most likely toincrease their calcification rate in response to rising alkalinity and saturationstate.
If suitable control of alkalinity were possible, it might benefit such species byprotecting them against the damaging effect of ocean acidification.
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EFFECTS OF ALKALINIZATION: Benthonic species
Experimental studies have been conducted on the capability of some marine species to produce and dissolute carbonate at elevated levels of alkalinity.
These deposit feeders process carbonate sand and rubble through their digestive tract and dissolve CaCO3 as part of their digestive process increasing ambient total alkalinity.
Density of animals: 1 ind/m2
This additional alkalinity could partially buffer changes in seawater pH associated with increasing atmospheric CO2 locally, thus reducing the impact of ocean acidification on coral growth.
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EFFECTS OF ALKALINIZATION: Phytoplankton
Studies have reviewed the pH tolerance of marine phytoplankton, one examining theresults obtained from batch culture experiments, the other from a variety of laboratoryand enclosure experiments.
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Response to variation of carbonateion concentration of seawater
Incomplete growth of coccolithsMalformed coccoliths
EFFECTS OF ALKALINIZATION: Phytoplankton
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Both studies show that changes in growth rate (or substrate uptake) for a given changein pH vary considerably. Some species are rather insensitive to changes in pH. However,there are species relatively sensitive to changes in pH.
pH values outside the range of 7.0 to 8.5 can preclude the growth of some species.
EFFECTS OF ALKALINIZATION: Phytoplankton
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The growth rates of the 3 dinoflagellates weremeasured at different pH within the range of 7.5to 10.
The growth rate was highest at pH 7.5 to 8.0 inall species.
It is evident from the compiled data on pH limitsfor marine phytoplankton growth that the abilityto tolerate high pH is not related to any particularalgal groups, but rather is species-specific.
In such environments, pH changes may drivespecies succession of phytoplankton and limitprimary production, because many species arequite sensitive to high pH.
EFFECTS OF ALKALINIZATION: Phytoplankton
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To avoid the risk of pH shock,
Water Quality Guidelines of both the U.S. EnvironmentalProtection Agency (1976) and the Canadian Council of Ministersof the Environment (1999)
recommend to protect marine biota with narrow pH tolerances,human activities should not result in a change in environmentalpH of more than 0.2 pH units from normally occurring values.
EFFECTS OF ALKALINIZATION: Guidelines
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EFFECTS OF ALKALINIZATION: Zooplankton
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Principaligruppitassonomicierappresentatividellozooplanctonoloplanctonico
PHYLUM SOTTOGRUPPI GENERICOMUNI
Protozoa Dinoflagellata Noctiluca
Zooflagellata Bodo
Foraminifera Globigerina
Radiolaria Aulcantha
Ciliophora Strombidium;Favella
Cnidaria Medusae Aglantha;Cynea
Siphonophora Physalia;Nanomia
Ctenophora Tentaculata Pleurobrachia
Nuda Boroe
Chaetognatha Sagitta
Annelida Polychaeta Tomopteris
Mollusca Heteropoda Atlanta
Thecosomata Limacina;Clio
Gymnosomata Clione
Arthropoda Cladocera Evadne;Podon
Ostracoda Conchoecia
Copepoda Calanus;Oithona
Mysidacea Neomysis
Amphipoda Parathemisto
Euphausiacea Euphausia
Decapoda Sergestes;Lucifer
Urochordata Appendicularia Oikopleura
Thaliacea Salpa;Pyrosoma
Principaligruppitassonomicierappresentatividellozooplanctonoloplanctonico Classiditagliaesuddivisioneincomponentiautotrofeedeterotrofedegliorganismidelplancton
GRUPPO TAGLIA ORGANISMIPRESENTI
Femtoplancton 0.02-0.2µm Viruspresentinellacolonnad'acqua
Picoplancton 0.2-2.0µm Batteri,Archaea,Cianobatteri,Picoeucariotiautotrofi
Nanoplancton 2.0-20µm Eucariotiunicellulari,diatomeebentoniche
Microplancton 20-200µm Microalgheplanctoniche,amebe,tintinnidi,foraminiferi,rotiferi
Mesoplancton 0.2-2.0cm Copepodi
Macroplancton 2.0-20cm Policheti,anfipodi
Megaplancton 20-200cm Meduse,sinofori,ctenofori
EFFECTS OF ALKALINIZATION: Zooplankton
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EFFECTS OF ALKALINIZATION: Zooplankton
Effective pH valuescausing toxic effectsin marine organisms.Copepod T. japonicusLC 50: 11mM DIC
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pH variability of the Mediterranean Sea
During the time-period of 1995-2011, at 10 m-depth:
• The estimated rate of pH decrease is 0.003 ±0.001 per year.
• The magnitude of seasonal pH variation at the Dyfamed site was 0.25 ± 0.03.
• pH fluctuated among years, ranging across 0.03, 0.05, 0.05, and 0.02 pH units in winter, spring, summer and fall, respectively.
pH CHANGES IN THE MARINE ENVIRONMENT
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MAIN ISSUES OF ALKALINIZATION
• Effects of ocean alkalization on ocean biogeochemistry andmarine ecosystems have mainly been explored throughtheoretical and modeling exercises and much less so inlaboratory or in-situ experiments;
• The bioavailability of important trace metals is likely impactedby changes in ocean chemistry;
• Food-web effects are complex and difficult to predict butbiomass and size structure of copepods (zooplanktonicorganisms) for example have seen to be negatively affected;
• Many factors in addition to acidification may influence algalcomposition, growth rates, and productivity (e.g. pollution, UV,sea surface temperature and limiting factors e.g. nitrate,phosphate, and iron) may play crucial role
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CONCLUSIONS
• Alkalinization has the potential to counter-balance the pH increasethat is occurring also in the Mediterranean sea;
• The available knowledge on the alkalinity enhancement is verylimited.
• Research on alkalization effects has focused on specific speciesrather than ecosystem.
• Experimental studies are required to improve the understanding of the responses of marine organisms and ecosystem to localized pH variations.