Exploring the effects of plastic ingestion on the energy budget Effects of plastic ingestion on the life cycle of an endangered sea turtle Exploring the effects of plastic ingestion on the energy budget Nina Marn, Marko Jusup, Tarzan Legović, ‘Bas’ Kooijman, Tin Klanjšček Ruđer Bošković Institute, Zagreb, Croatia nina.marn@gmail.com Tromsø, 01st June 2017

Motivation yearly production of plastic: 230 mil.tons yearly consumption: 100kg/capita – > 140kg/c (2015) growth in plastic production 1950-2009 source: P. Kershaw, S. Katsuhiko, S. Lee, J. Samseth, D. Woodring. UNEP year book 2011, Maarten Vanden Eynde

Motivation 100 milions tons of plastics in the ocean around 80% marine debris is plastic

almost 300 marine species affected Motivation ? almost 300 marine species affected

Loggerhead sea turtles long lived, migratory hard to study; vulnerable to environmental and anthropogenic pressures endangered

Loggerhead sea turtles long lived, migratory hard to study; vulnerable to environmental and anthropogenic pressures endangered www.5gyres.org

Loggerhead sea turtles long lived, migratory hard to study; vulnerable to environmental and anthropogenic pressures endangered www.5gyres.org

Dynamic Energy Budget (DEB) theory Making best use of existing data knowledge about the species (data) knowledge about processes (theory) pars estimat. Parameter estimates Model predictions Marn et al., (2017) Mar. Environ. Res.

Plastic ingestion Synthesizing units (SUs)  Assimilation units (AUs) Kooijman (1998), Biophys. Chem.

Plastic ingestion Synthesizing units (SUs)  Assimilation units (AUs) Busy or free

Plastic ingestion Synthesizing units (SUs)  Assimilation units (AUs) Busy or free

Plastic ingestion

Plastic lowers the scaled functional response Plastic ingestion Plastic lowers the scaled functional response

Plastic dilutes the food

More plastic, or plastic staying longer f =0.81 f =0.81 f =0.75 f =0.61 f =0.61 f =0.75

Same pattern as lower food availability slower maturation and lower reproduction quantified slower growth and smaller size of adults quantified

How much plastic? Depends on the amount and residence time at 14 % reproduction not likely

How much plastic? Depends on the amount and residence time at 14 % reproduction not likely Longer residence time = more plastic at 3 % puberty not reached

Conclusions mechanistic models plastic waste lower food availability could lead to population decline both residence time and amount of plastics in the gut need to be taken into account education and better waste management necessary Hawaii photo by: Rick Loomis

Thank you! Questions?