The researchers focused on four organisms: a stony coral, a soft coral, a fire coral and a single ascidian. These organisms play an important role in the ecology of tropical coral reefs, and damage to their reproduction and development can affect reef community structure.

In addition, the researchers examined four chemical additives commonly used in plastics and found in seawater in tropical areas where coral reefs live. Two of these were phthalate chemicals, which are used to soften and increase the flexibility of various types of plastics and can be found in a wide range of consumer products, including food packaging, toys, medical devices and adhesives.

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Others include the stabilizer 4-nonylphenol, used as an additive in plastic packaging and cleaning agents, and food and beverage packaging, baby bottles, cans, etc. was bisphenol A in polycarbonate plastic used for

Dive deep into plastic additives

Gal Vered explains: “Plastic additives are chemical additives added to plastic products during the manufacturing process. These substances reach the marine environment through plastic waste and sewage. Some of them are known to activate or suppress hormonal processes and therefore can disrupt biological systems. But their effects on organisms in coral reefs are almost unstudied. Coral reef population structure depends on the success of reproduction, development and settlement of corals and other reef organisms. Interfering with their hormonal systems can affect their chances of development. The success of these processes and the unequal impact on different species, can lead to a change in the structure of society and damage to the whole system.”

The researchers conducted a series of exposure experiments in which the effects of plastic additives were tested in seawater at ambient concentrations and at higher laboratory concentrations. The parameters measured were fertilization, larval development, larval survival, and larval settlement and metamorphosis.

Ambient concentrations of 4-nonylphenol were found to inhibit larval settlement in soft corals, while high concentrations of the same compound were found to impair fertilization, development, and settlement of all organisms tested. Higher laboratory concentrations of one of the phthalate chemicals studied harmed the settlement of stony coral larvae only, but not the reproductive products of other organisms. These findings add to the accumulating evidence that plastic pollution has selective effects on different species.

Prof. Shenkar: “Our findings demonstrate a negative and selective effect of plastic additives on the development and reproduction of coral reef organisms. The environmentally relevant concentrations used in our experiments were those found in seawater; alarmingly, some had harmful effects on the reproduction of the organisms. However, the concentration in the tissues of the organisms was higher can reach high levels because these compounds can potentially bioaccumulate. To better understand the impact of plastic additives on this endangered ecosystem, we suggest that better methods be developed to measure the actual concentrations in the tissues of organisms. Appropriate risk assessments.”

Gal Vered: “Climate change, ocean acidification, and ongoing anthropogenic stresses put coral reefs at existential risk. Most of the world’s coral reefs are found in developing countries where human populations are rapidly expanding and waste is not managed. Steps toward prevention include reducing the amount of plastic waste that reaches the environment. including proper local waste management that reduces transport and sustainable consumption of regulated products for supplements.”

The researchers conclude: “We emphasize the importance of proper waste management, which will reduce the entry of plastic waste into the marine environment, as well as the need for methods to measure the concentration of chemicals in organisms to assess their possible risk to their reproductive and developmental processes.”

Source: Eurekalert

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