It's not just the ocean we need to worry about – plastic is accumulating in the world's rivers, too.
The irukandji jellyfish can be deadly and particularly hard to trace. However, emerging technology offers a solution.
Lake Tana in Ethiopia has been massively affected by the invasive weed, water hyacinth. Control methods are available but there are challenges.
With El Niño ramping up, Australia is in for a long, hot, dry summer - perfect conditions for blue-green algae. And that innocuous-looking pond scum can pack a toxic punch if you're not careful.
Biological control is the best way to combat aquatic weeds in African water.