Mapping Marine Ecosystems

Mapping Marine Ecosystems

Why do we need to map the ocean?

The ocean is essential for all aspects of human well-being and livelihoods. Marine ecosystems provide food, moderate the climate, protect the coast and provide countless opportunities for recreation and cultural experiences. But the living conditions and resources in the enormous water masses of the ocean remain largely unknown and unmapped. 

It is a well-known fact that we know more about the surface of the moon than we do about the seafloor. For example, we know that on average the ocean is 3 km deep, but this doesn’t account for outliers like the Mariana Trench, which stretches to depths of 11 km. So, if we don’t even know the exact volume of the oceans, how can we manage them fairly and sustainably? There are many issues that must be addressed to fully understand and protect the oceans for future generations and maps are fundamental tools to advance research in this regard.

Although the ocean is vast, marine life is not uniformly distributed within it, and some ecosystems are more biologically rich than others. Coastal ecosystems generally contain more oxygen and nutrients and are warmer and sunlit. Thus, they are more diverse than open ocean ecosystems. Understanding and being able to visually represent these differences using mapping techniques is essential to monitor and properly manage marine ecosystems. Without this information we risk depleting vital resources and causing irreversible damage.

How do we map marine ecosystems?

The traditional and most commonly used sources of information to create maps of marine ecosystems are in-situ measurements, taken directly from the area of interest. Depending on the accessibility of the area, the logistical and equipment requirements can range from a pair of boots to SCUBA diving gear and even include oceanographic vessels, if mapping occurs in open ocean.

Another way of obtaining information that allows us to map marine ecosystems are remote sensing techniques, through satellite observations, for example. These techniques, in combination with traditional methods, have significantly contributed to updating navigational charts with coastline and bathymetric data, to mapping the distribution and types of coastal ecosystems and to monitoring the condition of coral reefs, amongst others.

In some cases, direct detection of ecosystems or species is not feasible with remote sensing techniques, for example due to depth or turbidity. Instead, indirect detection may be possible by observation and modelling of associated sea surface phenomena. For example, changes in ocean colour from blue to green may serve as an indicator of increasing plankton abundance. The green colour is associated with the presence of chlorophyll; the light retaining phytoplankton pigments. Water temperature is another important factor in determining ecosystems and species distribution. Thermal sensors can be used to produce maps of the sea surface temperature, which can be used to identify different water masses and draw boundaries among them.

Credits: Afonso Prestes, 2021

Beyond biophysical techniques

Both in-situ and remote sensing observations are techniques that provide information to map marine ecosystems from a biophysical perspective, i.e., based on biological, physical and chemical features, but they can also be mapped from a social perspective. Highly relevant maps based on human perceptions and socioeconomic knowledge on marine ecosystems can be produced for monitoring and management purposes. As an example, this link gives access to a publication on ecosystem services mapping in the Azores Archipelago, led by our partners from Fundação Gaspar Frutuoso (FGF). Despite not being a MaCoBioS case study area, the FGF team is developing complementary work in this European Union Outermost Region from Portugal, because its natural and social contexts and specificities make it a very interesting hotspot to study and map socio-ecological relationships in the coastal/marine environment.

Furthermore, along with Maynooth University (Ireland), the FGF team is supporting all the MaCoBioS partners in terms of remote sensing data prospecting, processing and analysis, to fill existing gaps in the characterization, assessment and monitoring of the project’s case study areas. The FGF will also set up the MaCoBioS WebGIS platform, an online tool with geospatial capabilities for partners, stakeholders and the general public to visualize and analyse the georeferenced project’s outputs.

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