Space4SDG14: Life Below Water

Published by- Joy Agrawal on 23/07/2021

Preservation of life all around is quintessential, even a centipede is as important as a lion because all this maintains the ecological balance. Life below water also helps maintain that very balance and more importantly has social and economic benefits for the human civilisation. Life below water serves as food for major proportion of people it serves a source of sustenance for others. Most of our fresh water comes from the oceans and life below it helps ensure the quality of water through various methods. More importantly its a moral duty towards preservation of marine ecosystem because we have been sharing the Earth with them and we have been polluting oceans and hence for continuity of not only humans but also the marine ecosystem. Space technology can aid in a number of ways to contribute towards this goal.

Until now you must have understood one thing that space tech and its contribution towards the SDGs is mainly in form of imagery and analysis of the images. Space imagery can help monitor the activity over protected areas. For instance the great barrier reef a natural wonder visible from space is protected, space imagery can be used to monitor this marvellous creation of nature.

Illegal fishing is on the increase and this does serious damage to the nature. In a way this problem was created by space technology mostly because of the newer technologies that enable monitoring the chlorophyll content which can be used to locate the shoal of fishes. This has led to increased efficiency of fish catchers but has led to over fishing. This damages the marine ecosystem and endangers the species. Imagery can help curb overfishing.

How exactly does this work?

So essentially all fishers need to register with the local authorities in order to receive a license. The local authorities maintain the registry of vessels authorised for fishing and therefore help put a check on illegal fishing. Every authorised vessel is attached with a Global Navigation Satellite System setup to track the live position, functions being many one important is tracking the fishing hotspots and zones and secondly in rescue efforts in case of worsening weather conditions. So the satellite while passing overhead utilising a Synthetic Aperture Radar(SAR) can detect the topography to high accuracy and can be used for the detection of boats and that can be cross referenced against the location of the authorised boats thus help in detecting and curbing illegal fishing. Main advantage of SAR is that it works on the principle of emission, reflection and detection so this method can work at night as well.

One major man made marine disaster that severely affects all life is oil spills. Oil spills have negative health effects on the marine life. Surface marine life faces obvious dangers due to toxic liquid. So how can such oil spills be detected?

Again the answer is SAR that is Synthetic Aperture Radar. The oil slick is so distinctive and black that is absorbs a lot of wavelengths of light and therefore lesser microwaves are reflected back from the Oil slick region to the radar and appears as a black regions on the image and comparing it with the map to identify if it is something known the distinctive black region can be differentiated from the surrounding ocean thus detecting the oil spill and intimating authorities to initiate the damage repair.

Another major application of space tech is sea surface temperature, because this can be used to identify the weather patterns and more importantly the migration pattern of animals and develop models that will help decide the migration of aquatic life using surface temperature, regions found, tolerable temperature and oceanic currents.

Finally one of the most important application is detection of algal blooms. When water runs off agricultural fields containing fertilisers and elements like nitrogen and phosphorus and accumulate in water bodies. Algae groups flourish over the surface of the water body. Its rises exponentially and this process is known as eutrophication, algal bloom slowly covers the whole surface thus limiting sunlight to the ground and slowly aquatic plants die eventually small fishes and finally the large fishes and the water body becomes dead. Detection, tracking and immediately tackling of algal blooms can prevent the loss of the marine ecosystem. The algae responsible for this mainly is detected by detection of chlorophyll and a distinctive marker pigment from satellite imagery.

Finally, plastics are the major pollutants affecting marine life. Ingestion of plastic can cause tremendous problems for the aquatic life. Suffocation due it is the major reason for the ill omen for the marine ecosystem. Majorly physical entanglement leads to a major problem. Imagine we have polluted the ocean so much that all needed to detect plastic from satellites is the colours of the ocean. Our litter is visible from space. Detection can aid in cleaning efforts which is crucial in this stage to preserve our marine ecosystem.

As discussed above, satellite imagery is key to helping keep the marine ecosystem free from the effects of industrialisation.