DR ANJANI GANASE
Every new technology and sustainable intention will affect the ocean. Dr Anjani Ganase, marine biologist, laments the idea that the ocean seems still ripe for exploitation.
Currently, there are three long-standing drivers of change impacting ocean biodiversity - over exploitation, pollution and climate change. Expanding human appetites continue to chip away at natural resources, with no regard for other life and without proper management of waste. In addition to these chronic conditions, a recent study produced a global checklist of emerging issues that are likely to become substantial in the next five to ten years. Several marine scientists, practitioners, policy makers around the world surveyed the likely issues affecting our ocean. The major issues emerge under the themes of ecosystem impacts, resource exploitation and the consequences of new technology and shifting standards. Here we review some of the major impacts on the ocean in the near future.
Ecosystem changes
Climate change is impacting the ocean in ways we could never have imagined. This year, wildfires have ravaged most of continental areas, including USA, Brazil, Europe and Australia. While there is obvious loss of natural habitat and wildlife, wildfires release significant amounts of stored carbon, aerosols and particulates, such as nutrients (nitrogen, phosphorus) and metals (lead and iron) into the atmosphere that get carried away by winds and rivers to the ocean. Such high injections of nutrients and metals lead to algae blooms in rivers, estuaries and nearshore marine areas that lead to plankton blooms and result in fish kill.
The accumulation of discharge from land also results in a general darkening of coastal waters from pollutants, sediment resuspension and algae blooms that block sunlight essential for shallow habitats like coral reefs and seagrass meadows. This is likely to be exacerbated in the next few years.
Our seafood is becoming more polluted and less nutritious with climate change. The toxicity of metal pollutants constantly recirculated (from trawling and dredging) and added via industrial and urban discharges will worsen with ocean acidification. More acidic conditions increase absorption of metals into organisms with potential toxic effects. This can be a concern for commercial species such as bivalves - oysters and clams that filter feed.
Our seafood is also becoming less nutritious as essential fatty acids found in seafood and consumed by billions of people around the world become degraded. Essential fatty acids are generated in phytoplankton which is then consumed and built up in the bodies of fish, especially slow-growing species in temperate regions. Warming conditions means that the production of fatty acids in phytoplankton will be impaired and scientists expect a decline in the fatty acids present in fish by ten to sixty per cent by 2100.
One of the biggest ecosystem impacts to be expected is the redistribution of marine life polewards as ocean temperatures soar. This polewa
