The world’s oceans and coastal areas are vital to human wellbeing. They absorb and store carbon dioxide, regulate the climate, support biodiversity, and provide food resources, jobs, and opportunities for recreation. At the same time, marine ecosystems are among the environments most heavily affected by human activity. Recent research by the Environmental Management Research Laboratory team at Mykolas Romeris University (MRU), led by Prof. Dr. Paulo Pereira, highlights why understanding the condition of marine ecosystems is more important than ever—and why this task is far more complex than it may seem.

Assessing Marine Ecosystems through SEEA-EA

The article examines how countries can assess the condition of marine ecosystems using the United Nations System of Environmental-Economic Accounting – Ecosystem Accounting (SEEA-EA). Adopted in 2021, this global framework helps countries understand and monitor the importance of nature for everyday life and how healthy ecosystems contribute to national economies. While SEEA-EA is increasingly applied to terrestrial ecosystems, its implementation in marine environments remains limited. The MRU research team sought to identify the key obstacles that prevent reliable assessments of marine ecosystem condition.

From Data to Insights

The researchers reviewed marine ecosystem accounting practices from various countries, including France, Norway, Australia, and the United States. They examined which ecological variables are commonly used (such as water quality, biodiversity, and pollution), how reference conditions are defined—serving as a baseline or example of a healthy ecosystem against which current conditions are compared—and how different indicators are combined into an overall condition index. The analysis drew on scientific literature, international initiatives, monitoring data, and policy documents, providing a comprehensive picture of current challenges.

The research highlights three major challenges:

1. Selecting appropriate condition indicators
There is currently no consensus on which ecological measurements best represent the condition of marine ecosystems. Different studies use widely varying numbers of indicators, ranging from just one to several dozen. In addition, marine data remain scarce and unevenly distributed.

2. Defining what constitutes a “good condition”
In many regions, it is nearly impossible to identify or restore natural marine ecosystems that remain largely untouched by human activity. Marine systems change naturally over time, and pollution easily crosses national borders. As a result, finding suitable reference areas or time periods is difficult, and thresholds set in legal or policy documents do not always apply across regions.

3. Combining indicators into a single index without bias
Even when indicators are rescaled, decisions must be made about how to combine them. Different weighting choices can lead to different outcomes, and determining whether all indicators should be considered equally important inevitably involves a degree of subjectivity.

Why This Matters

A reliable assessment of marine ecosystem condition is essential for protecting biodiversity, managing natural resources sustainably, and understanding how environmental degradation affects human wellbeing—from food provision and coastal protection to climate regulation. Inaccurate or incomplete assessments make decision-making more difficult and weaken the link between ecosystem health and societal needs.

Looking Ahead

The MRU team emphasizes the need for clearer international guidelines, shared data platforms, and more consistent methodologies. As more countries adopt the SEEA-EA framework, standardization will be crucial for effectively monitoring changes in marine ecosystems and their impacts on human wellbeing. This study represents an important step toward identifying existing barriers and proposing solutions for the future.

Read more about it here.