‘Iron-breathing’ microbe which eliminate toxic sulfide from Earth discovered by scientists – The Economic Times

Report on the Discovery of MISO Bacteria and Implications for Sustainable Development Goals

Executive Summary

An international research team has identified a novel microbial metabolism, termed Microbial Iron-Sulfide Oxidation (MISO), with significant implications for global biogeochemical cycles and the achievement of several Sustainable Development Goals (SDGs). Published in Nature, the study reveals that specific bacteria utilize iron minerals to neutralize toxic sulfide, a process previously thought to be purely chemical. This discovery directly impacts efforts related to SDG 14 (Life Below Water), SDG 13 (Climate Action), and SDG 6 (Clean Water and Sanitation) by highlighting a natural mechanism for pollution control, carbon sequestration, and water purification.

Key Findings of the Research

A Novel Biological Pathway

The research, led by the University of Vienna, identified that MISO bacteria “breathe” iron(III) oxide minerals to oxidize hydrogen sulfide. This biological process is distinct from and more rapid than the equivalent abiotic chemical reaction.

• The metabolism directly converts toxic sulfide into non-toxic sulfate.
• The genetic capacity for MISO is widespread, found in diverse bacteria and archaea across various natural and engineered environments.
• Laboratory experiments confirmed that the enzymatically catalyzed reaction is significantly faster than the chemical alternative, suggesting microbes are the primary drivers of this process in nature.

Global Biogeochemical Significance

The study repositions microorganisms as central players in linking the global sulfur, iron, and carbon cycles in oxygen-free environments. The MISO process is estimated to be a major contributor to elemental cycling on a planetary scale.

1. In marine sediments, MISO may be responsible for up to 7% of global sulfide oxidation.
2. The process is fueled by reactive iron supplied to oceans from rivers and melting glaciers, connecting it to broader climate-related Earth systems.
3. It reveals a previously unknown biological mechanism that regulates the accumulation of toxic sulfide in environments like marine sediments, wetlands, and aquifers.

Alignment with Sustainable Development Goals (SDGs)

SDG 14: Life Below Water

The discovery of MISO bacteria presents a significant natural mechanism for protecting marine ecosystems, directly contributing to the targets of SDG 14.

• Combating Marine Pollution (Target 14.1): By removing toxic hydrogen sulfide, MISO bacteria actively detoxify marine sediments, mitigating a key source of pollution in coastal environments.
• Protecting Marine Ecosystems (Target 14.2): The bacteria’s activity may help prevent the formation and expansion of oxygen-depleted “dead zones,” which are uninhabitable for most marine life. This function is critical for preserving marine biodiversity and ecosystem health.

SDG 13: Climate Action

The metabolic activity of MISO bacteria includes a vital climate-regulating function, aligning with the objectives of SDG 13.

• Carbon Sequestration: Similar to plants, MISO bacteria fix atmospheric carbon dioxide for growth while carrying out their metabolic functions. This natural carbon sink contributes to the mitigation of greenhouse gas accumulation.

SDG 6: Clean Water and Sanitation & SDG 15: Life on Land

The prevalence of MISO bacteria in various aquatic and terrestrial environments underscores their importance for water quality and ecosystem health.

• Improving Water Quality (Target 6.3): In wetlands and underground aquifers, these microorganisms remove toxic sulfide, naturally purifying water resources and contributing to the health of freshwater ecosystems.
• Protecting Terrestrial Ecosystems (Target 15.1): By regulating biogeochemical cycles in wetlands, MISO bacteria play an indispensable role in maintaining the health and function of these critical habitats.

Conclusion

The identification of the MISO metabolic pathway is a fundamental advance in microbiology and environmental science. It highlights the profound role of microorganisms in maintaining planetary health and provides new insights into natural processes that support the achievement of critical Sustainable Development Goals. This discovery underscores the importance of microbial ecosystems in regulating global element cycles, controlling pollution, and mitigating climate change, reinforcing the need to protect these unseen yet vital components of our planet’s systems.

Which SDGs are addressed or connected to the issues highlighted in the article?

1. SDG 14: Life Below Water

   • The article directly addresses this goal by discussing the health of marine environments. The discovery of MISO bacteria and their role in removing toxic sulfide is presented as a mechanism that “may help prevent the expansion of so-called ‘dead zones’ in aquatic environments, while fixing carbon dioxide for growth.” Dead zones are a major threat to marine life, making this research highly relevant to the conservation and health of oceans and seas.

2. SDG 13: Climate Action

   • The article connects to climate action through the carbon cycle. It states that MISO bacteria contribute to “fixing carbon dioxide for growth – similar to plants.” This process, known as carbon fixation, is crucial for removing CO2, a primary greenhouse gas, from the environment. The article also notes that the interplay of sulfur and iron cycles, driven by microbes, affects the “production or breakdown of greenhouse gases such as carbon dioxide and methane.”

3. SDG 6: Clean Water and Sanitation

   • This goal is relevant because the bacteria’s primary function discussed is detoxification. The article explains that MISO bacteria “remove toxic sulfide” from environments including “marine sediments, wetlands, and underground aquifers.” Hydrogen sulfide is a pollutant, and its removal by these microbes contributes to improving the quality of water in these natural systems.

4. SDG 15: Life on Land

   • The research is applicable to terrestrial ecosystems, specifically wetlands. The article mentions that hydrogen sulfide production and the MISO process occur in “oxygen-free habitats such as marine sediments, wetlands, and underground aquifers.” By detoxifying sulfide in wetlands, these bacteria play a role in maintaining the health and biogeochemical balance of these critical inland ecosystems.

5. SDG 9: Industry, Innovation and Infrastructure

   • The entire article is centered on a scientific discovery made by an “international research team led by microbiologists… at the University of Vienna.” This represents a significant advancement in scientific knowledge and research. The findings, published in a major scientific journal, contribute to the global scientific infrastructure and highlight the importance of funding research, as noted by the support from the “Austrian Science Fund (FWF).”

What specific targets under those SDGs can be identified based on the article’s content?

1. Target 14.1: Reduce marine pollution

   • The article’s focus on preventing “dead zones” directly aligns with this target, which aims to “prevent and significantly reduce marine pollution of all kinds.” The MISO bacteria’s ability to remove “toxic sulfide” from marine sediments is a natural mechanism that mitigates a form of chemical pollution that contributes to the formation of these oxygen-depleted zones.

2. Target 14.a: Increase scientific knowledge and research capacity for ocean health

   • The research itself embodies this target. The article describes a novel discovery that “reveal[s] a previously unknown biological mechanism that links sulfur, iron, and carbon cycling in oxygen-free environments.” This new understanding enhances scientific knowledge and improves our capacity to understand and protect marine ecosystems.

3. Target 6.3: Improve water quality by reducing pollution

   • This target aims to “improve water quality by reducing pollution… and minimizing release of hazardous chemicals.” The article shows how MISO bacteria naturally contribute to this goal by metabolizing and removing toxic hydrogen sulfide from various aquatic environments, including underground aquifers, thereby improving water quality.

4. Target 13.3: Improve education, awareness-raising and human and institutional capacity on climate change mitigation

   • The discovery contributes to the institutional and scientific capacity for climate change mitigation. By identifying a natural process of carbon fixation (“fixing carbon dioxide for growth”), the research adds to our understanding of the global carbon cycle, which is fundamental to developing strategies for climate change mitigation.

5. Target 9.5: Enhance scientific research and innovation

   • The work of the research team, which “identified a previously unknown form of microbial metabolism,” is a direct example of enhancing scientific research. The study, which “demonstrates the metabolic ingenuity of microorganisms,” encourages further innovation and understanding in microbiology and environmental science.

Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

1. Proportion of global sulfide oxidation (Explicit)

   • The article provides a specific, quantifiable indicator: “In marine sediments, MISO could account for up to 7% of global sulfide oxidation to sulfate.” This metric can be used to measure the contribution of this newly discovered biological process to global biogeochemical cycles, directly relating to the reduction of sulfide pollution (Target 14.1 and 6.3).

2. Area of oxygen-depleted “dead zones” (Implied)

   • The article suggests that MISO bacteria “may help prevent the expansion of so-called ‘dead zones’.” An implied indicator for progress would therefore be the measurement of the size and number of these hypoxic zones in global aquatic environments. A reduction or stabilization of these areas could be partly attributed to natural processes like MISO.

3. Rate of microbial carbon fixation (Implied)

   • The statement that MISO bacteria are “fixing carbon dioxide for growth” implies that the rate of this carbon sequestration could be measured. Quantifying the amount of CO2 fixed by these specific microbial populations in various environments would serve as an indicator for their contribution to climate change mitigation (Target 13.3).

4. Number of scientific publications and research projects (Implied)

   • The article itself, being a report on findings “published in Nature,” is an indicator of scientific output. The number of research publications, funded projects (like the one supported by the “Austrian Science Fund”), and international collaborations are measurable indicators of progress towards enhancing scientific research and knowledge (Target 9.5 and 14.a).

Table of SDGs, Targets, and Indicators

Source: m.economictimes.com