Plastic’s Silent Assault on Marine Life

Dear reader, last week, we saw how microplastics enter the aquatic food chain and eventually reach giants such as whales. This week, let us move a little further through the marine world and understand how plastic pollution is harming other ocean creatures as well, including sea turtles, seabirds and many other marine species.

Like many other animals, sea turtles have been around for 100 million years. They have survived periodical mass extinctions and they have survived through the “Golden Age of Reptiles”, outliving the dinosaurs who once ruled the Earth. But now their survival is at stake, and they are struggling to withstand the impacts of plastics on them and their environments.

There are seven different species of sea turtles living in the oceans, and all of them are at high risk from plastic. Depending upon the species, their natural food includes sea animals and plants such as jellyfish, crabs, shrimps, corals, algae and seagrass. But plastic has never been part of their diet. How could it be? However, when a turtle comes across a light, translucent polythene bag floating on the surface of water and moving along with the current, it gets delighted, thinking that the bag is a jellyfish. Yes, that floating bag looks exactly like a jellyfish, and so it immediately grabs the bag in its mouth and gulps it down.

Such ingested plastic bags and other plastic items keep accumulating in the poor turtle’s stomach, giving it a sense of fullness. However, in the long run, this leads to starvation and, ultimately, death. In addition to this, plastic articles thus swallowed can also damage the delicate lining of the gut wall. Many a time, plastic straws — used by us to sip a cold drink, lassi or similar beverages and later discarded in the dustbin — are found stuck in a turtle’s nose, injuring its delicate inner tissue lining. Scientists have also found that plastic debris settling on algae or seagrass is easily consumed by turtles while eating their natural food.

Another major hazard turtles have to face is entanglement in worn-out and discarded fishing gear, often labelled as 'ghost nets'. Most of the time, fisherfolk do not bother about repairing torn and worn-out nets and simply discard them in the oceans. Turtles get trapped in such nets and find it impossible to swim around. With restricted movements or no movement at all, turtles rarely survive. Additionally, microplastic consumption is also taking a heavy toll on the survival of turtles.

Seabirds at Risk

Seabirds are especially vulnerable to plastic pollution because of their surface-feeding habits. Often, they mistake floating plastic debris for food, which can lead to internal blockages, tears, starvation and toxic accumulation in their bodies. Alarmingly, some seabirds have even been observed feeding plastic to their chicks, putting entire populations at risk. (See the accompanying cartoon as an eye-opener!)

The threat is so severe that a new disease — plasticosis (plastic-induced fibrosis) — has emerged exclusively in seabirds. In this condition, tiny pieces of plastic irritate the digestive tract and cause scar tissue formation, which disrupts their growth, digestion and overall health.

According to the Ocean Blue Project, plastic waste kills an estimated one million seabirds every year through ingestion, entanglement and toxicity, while nearly 90 per cent of seabirds have already ingested plastic by mistake. By 2050, it is projected that 99 per cent of seabird species will be affected by plastic ingestion. And now comes an important question: what about us humans? Let us explore that next Saturday. Till then, have a great weekend!

(The writer is an environmentalist. Views personal.)