By Ángel Borja
Editor’s note: This work is a product of the DEVOTES project (DEVelopment Of innovative Tools for understanding marine biodiversity and assessing good Environmental Status), a project for developing tools for the implementation of marine legislation management, funded by the European Union. Ángel Borja is coordinator of the DEVOTES project as well as head of projects at AZTI Tecnalia and a member of the Scientific Committee of the European Environment Agency. He can be reached at firstname.lastname@example.org.
Traditional methods of monitoring spatial and temporal variations in marine environments are generally time-consuming, costly, and low-resolution. This makes monitoring the 7 million km2 of the European Economic Exclusive Zone (or any large marine area) a daunting task. To help address this situation, the DEVOTES project developed and tested a range of promising new monitoring approaches – including molecular, remote sensing, acoustic, visual, and in situ approaches – for performance, accuracy, and cost.
The DEVOTES project developed and tested approaches and made advances in areas including:
Metabarcoding: Metabarcoding is a biodiversity assessment method that combines DNA-based identification and high-throughput DNA sequencing to infer the species composition of an environmental sample. The DEVOTES project found that metabarcoding:
- Allows faster identification of microbes, plankton, meiofauna, and macroinvertebrates than classical approaches
- Allows early detection of non-indigenous species, including those in ballast water
- Can reveal eukaryotic diversity when used for extracellular DNA (DNA not enclosed in living cells) in seawater
- Can be used to assess the status of marine bacteria
- Can be used to apply a commonly used macroinvertebrate biotic index (AMBI) more quickly and at lower cost, thus a genomic AMBI.
Microarrays: Microarrays are microscope slides printed with thousands of molecules or DNA or protein fragments that are used for biochemical and genetic analysis. DEVOTES found that microarrays can be used to detect a large number of toxic algae species.
Remote sensing: Remote sensing is the use of satellite- or aircraft-based sensors to estimate properties of the Earth’s surface and atmosphere. It can be a cost-effective option for monitoring large marine areas. Monitoring ocean color via remote sensing and estimating the abundance of chlorophyll a from this provides information on the abundance of marine phytoplankton biomass. The DEVOTES project found that ocean color remote sensing in conjunction with bio-optical models (estimations of the optical properties of a water body as a function of biological activity) can be used to detect and track the development of algal blooms (including harmful ones) in marine waters. In addition, remote sensing was shown to help with identifying shelf-sea fronts, estimating pelagic biodiversity, and – in combination with microscopy and bio-optical methods –monitoring phytoplankton community composition such as the ratio between diatoms and flagellates.
Remotely operated vehicle (ROV) video: ROV video was validated against traditional faunal analyses and underwater hyperspectral imagery to demonstrate that it can effectively detect anthropogenic seafloor smothering.
Multibeam echo-sounder: Multibeam echo-sounder refers to sonar systems that emit sound waves in a fan shape beneath a ship’s hull to map the seabed. The DEVOTES project combined multibeam sonar-derived seabed geological information with biological variables to assess seafloor integrity. In addition, the DEVOTES project collected high-resolution multibeam echo-sounder data from existing monitoring programs and extrapolated these properties to large areas.
Visual methods: Visual methods, including image scanning and the ZooImage free software, were used for semi-automated classification of zooplankton samples.
Non-invasive biosensors: The biorhythmic gaping behavior of clams in response to environmental changes can be a high frequency, non-invasive biosensor to provide early warnings of marine contamination.
Artificial structures: The DEVOTES project collaborated with NOAA to extend use of autonomous reef monitoring structures (ARMS) – small, long-term collecting devices designed to mimic the structural complexity of reefs and attract colonizing invertebrates – to European and Red Seas. The project added artificial substrate units (ASUs) – nylon pot scrubbers – to monitor rocky substrata. These have been used in combination with photo analysis and genomic tools and were found to be useful for hard-bottom benthic biodiversity monitoring. These monitoring methods can be standardized and used to compare the status across different seas in an equivalent way.
The DEVOTES project’s development and testing of these new methods will contribute tremendously to more cost-effective marine monitoring in Europe and can be readily applied to other marine areas. Read more about this work.