The **Amazon**, globally recognized as the **green lung of the planet**, not only houses the [greatest terrestrial biodiversity](https://noticiasambientales.com/medio-ambiente/brasil-refuerza-la-defensa-de-la-amazonia-con-un-sistema-satelital-de-monitoreo-diario-para-su-conservacion/), but also **hides an underground ocean**: the **Amazon Large Aquifer System (SAGA)**, a network of **underground freshwater reserves** with an estimated volume of over **160 trillion cubic meters**.
This discovery, presented by researcher **Francisco de Assis Matos de Abreu** (UFPA), surpasses the **[Guaraní Aquifer](https://noticiasambientales.com/medio-ambiente/recursos-hidricos-primer-encuentro-de-argentina-brasil-paraguay-y-uruguay-por-el-acuifero-guarani/)** by **3.5 times**, previously considered one of the largest in the world.
## A continental-scale hydrogeological system
The Acre, Solimões, Amazonas, and Marajó basins make up a **strategic reservoir**.
The SAGA extends over **1.3 million square kilometers**, covering the **sedimentary basins** of the main Amazonian rivers. Its volume represents **over 80% of the water in the regional hydrological cycle**, while rivers and the atmosphere contribute only **8% each**.
This data transforms the understanding of the **Amazonian water balance**, revealing that **the subsoil is the true aquatic engine of the jungle**.
## Alter do Chão: the starting point of a scientific revelation
Research began a decade ago in the **Alter do Chão Aquifer** in Santarém (Pará), where a deposit of **86.4 trillion cubic meters** was identified.
Later, it was confirmed that this aquifer was part of a much larger system, composed of **multiple sedimentary basins**, giving rise to the concept of SAGA.
## Ecological and climatic function of the SAGA
The underground aquifer not only sustains the **Amazon rainforest**, but also annually transfers around **8 trillion cubic meters of water** to other regions of Brazil.
This flow is vital for **agriculture**, **filling hydroelectric reservoirs**, and the **climate stability** of the country. Its role in the **water cycle** makes it a **strategic resource for South America**.
## Technical challenges and environmental risks
Accurate mapping, **water quality**, and international cooperation are key to its management.
Despite its magnitude, the **water quality** in the deeper layers is still unknown. Current wells do not exceed **500 meters**, limiting the assessment of their **potability and suitability for human or industrial use**. Additionally, the **geological complexity** of the system requires detailed **mapping** to understand its flows and dynamics.
“The greatest challenge is not discovering it, but managing it wisely,” warn the researchers.
**Deforestation**, **pollution**, and **uncontrolled exploitation** threaten the balance between the jungle and its water resources. Being a **transboundary system**, the SAGA demands **international cooperation** for its **preservation and sustainable use**.
