Dolphins may be getting an Alzheimer’s-like disease due to this neurotoxin – Popular Science

Report on the Link Between Algal Blooms, Marine Life, and Human Health in the Context of Sustainable Development Goals

Executive Summary

A recent study reveals a significant link between neurotoxins from harmful algal blooms and Alzheimer’s-like brain disease in dolphins. As sentinel species, the health of these marine mammals provides a critical warning about broader environmental hazards that threaten marine ecosystems and human populations. This directly impacts several Sustainable Development Goals (SDGs), including SDG 3 (Good Health and Well-being), SDG 14 (Life Below Water), and SDG 6 (Clean Water and Sanitation).

Sentinel Species as Indicators for SDG 14: Life Below Water

Marine biologists consider dolphins to be sentinel species, meaning their physiological state serves as an early warning system for the health of marine environments.

• The health of cetacean species like dolphins, whales, and porpoises reflects the overall condition of the ocean.
• Monitoring these species helps identify environmental hazards that can affect entire ecosystems, a key concern for achieving the targets of SDG 14, which aims to conserve and sustainably use the oceans, seas, and marine resources.

Research Findings: Neurotoxin Impact on Marine Mammals

A study published in Communications Biology has established a direct connection between environmental toxins and neurological damage in dolphins in Florida’s Indian River Lagoon.

1. High Toxin Levels: Dolphins stranded during algal bloom seasons exhibited concentrations of the neurotoxin 2,4-diaminobutyric acid (2,4-DAB) that were 2,900 times higher than those found during non-bloom seasons.
2. Neurological Damage: Higher concentrations of 2,4-DAB correlated with severe brain changes characteristic of early-stage Alzheimer’s disease, including the buildup of insoluble proteins and alterations in genes related to brain health and memory.
3. Consistent Threat: These findings were consistent across nearly a decade of dolphin strandings, with the severity of brain changes increasing with each subsequent algal bloom season.

Implications for Global Sustainable Development Goals

The study’s findings have profound implications for several SDGs, highlighting the interconnectedness of environmental and human health.

• SDG 3: Good Health and Well-being: The presence of Alzheimer’s-like pathology in dolphins raises serious concerns for human health. Coastal communities are exposed to the same cyanobacterial toxins, suggesting an increased risk factor for neurodegenerative diseases. This underscores the need to protect human populations from environmental health hazards.
• SDG 14: Life Below Water: The direct harm to dolphins demonstrates the acute threat that harmful algal blooms pose to marine biodiversity and the stability of aquatic ecosystems.
• SDG 6 (Clean Water and Sanitation) and SDG 13 (Climate Action): The report identifies the primary drivers of these toxic blooms as nutrient pollution, sewage, and a warming climate. These factors represent a failure to meet the targets of SDG 6 (reducing water pollution) and SDG 13 (combating climate change and its impacts).

Conclusion and Path Forward

The link between algal bloom neurotoxins and neurological disease in dolphins is a critical indicator of deteriorating environmental conditions that threaten both marine and human life. Addressing this issue requires a multi-faceted approach aligned with the Sustainable Development Goals. Urgent action is needed to mitigate nutrient pollution, improve sanitation infrastructure, and combat climate change to protect our oceans and public health. Further research into the consequences of exposure to these toxins is imperative.

Analysis of SDGs, Targets, and Indicators

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

1. SDG 3: Good Health and Well-being: The article directly connects environmental hazards to health risks. It discusses how neurotoxins from algal blooms cause brain changes in dolphins similar to Alzheimer’s disease and raises concerns about the potential for similar human health issues, as people share the same coastal environments.
2. SDG 14: Life Below Water: The core of the article focuses on the health of marine ecosystems. It uses dolphins as a “sentinel species” to gauge ocean health and highlights the detrimental impact of marine pollution (algal blooms and their toxins) on marine life. The article explicitly mentions the Indian River Lagoon, a coastal ecosystem affected by these blooms.
3. SDG 6: Clean Water and Sanitation: The article identifies some of the root causes of the intensified algal blooms, specifically mentioning “nutrient pollution, and sewage.” This points directly to issues of water quality and the management of wastewater, which are central to SDG 6.
4. SDG 13: Climate Action: The article states that a “warming climate” is a factor that will “continue to intensify such harmful algal blooms.” This links the problem of toxic algal blooms and its subsequent health and ecosystem impacts to the broader issue of climate change.

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

1. Under SDG 3 (Good Health and Well-being):
   • Target 3.9: “By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination.” The article’s focus on neurotoxins (hazardous chemicals) from algal blooms (water pollution) causing Alzheimer’s-like disease in dolphins and posing a risk to humans directly relates to this target.
2. Under SDG 14 (Life Below Water):
   • Target 14.1: “By 2025, prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution.” The article explicitly names “nutrient pollution” and “sewage” from land as causes for the intensification of harmful algal blooms, which constitute a form of marine pollution.
   • Target 14.2: “By 2020, sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts…” The health of the dolphin population and the Indian River Lagoon ecosystem is shown to be adversely impacted by the pollution, aligning with the goal of protecting these environments.
3. Under SDG 6 (Clean Water and Sanitation):
   • Target 6.3: “By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater…” The mention of “sewage” and “nutrient pollution” as drivers of algal blooms connects directly to the need to improve water quality by managing wastewater and pollutants.
4. Under SDG 13 (Climate Action):
   • Target 13.2: “Integrate climate change measures into national policies, strategies and planning.” The article’s statement that a “warming climate” intensifies algal blooms implies that addressing climate change is a necessary part of the solution, which is the focus of this target.

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

1. Concentration of Neurotoxins in Marine Life: The article provides a specific, quantifiable measure. It states that dolphins stranded during bloom season had “2,900 times the concentration of 2,4-DAB than those from non-bloom seasons.” Monitoring the concentration of this neurotoxin in sentinel species like dolphins serves as a direct indicator of water contamination and progress towards Target 3.9 and 14.1.
2. Incidence of Disease in Sentinel Species: The article links higher neurotoxin levels to “more severe changes in their brain chemistry and tissue that are associated with early Alzheimer’s disease.” Tracking the prevalence and severity of these physiological changes in dolphins can act as an indicator of the overall health of the marine ecosystem (Target 14.2) and the level of risk from water pollution (Target 3.9).
3. Frequency and Intensity of Harmful Algal Blooms: The article refers to the “algal bloom season” and notes that the negative effects were “more drastic with each algal bloom season.” Therefore, tracking the frequency, duration, and geographic extent of these blooms is an implied indicator for measuring the scale of marine and water pollution (Targets 14.1 and 6.3).

4. Summary Table of SDGs, Targets, and Indicators

Source: popsci.com