Water drop with copepod and micro plastics in Arctic landscape. Photo and graphics: Rocio Rodrigues Torres

PhD defence about ingestion and effects of microplastics on marine planktonic food webs

Wednesday 30 Mar 22


Torkel Gissel Nielsen
DTU Aqua
+45 35 88 34 94

On 6 April 2022, Rocío Rodríguez Torres from DTU Aqua will defend her PhD thesis. It is possible to attend the defence at DTU in Lyngby and online.

Microplastics (plastic particles less than 5 mm) are ubiquitous in the marine environment and their bioavailability make them a potential risk for the marine ecosystems. 

Sampling of microplastics in the Arctic is scarce, but Rocío Rodríguez Torres contributes with new knowledge on the topic through her PhD study at DTU Aqua. On 6 April 2022 she will defend her thesis “Ingestion and effects of microplastics on marine planktonic food webs” at DTU. 

Rocío Rodríguez Torres has quantified the concentrations of microplastics in surface waters in the Arctic and has evaluated the ingestion and effects of microplastics on arctic key copepod species. Furthermore, Rocío Rodríguez Torres has studied how copepods respond to different microplastic types and how micro plastics influence the copepod’s foraging behavior. 

Her laboratory studies using virgin microplastics particles showed that artic copepods’ microplastic ingestion varied with food concentration, but when ingested the copepods were not affected by microplastics even at concentrations far above the concentrations found in the arctic environment.

She has also showed that planktonic copepods had the ability to select their prey and that 80 percent of the captured microplastics independently on the microplastic type were rejected. In addition, the presence of microplastics did not affect the copepods’ behavioral responses, and the ingestion of microplastics was similarly low for all studied foraging behaviors.

Rocío Rodíguez Torres concludes that given the low microplastic concentration found in surface waters and the ability of copepods to reject microplastics, the risk of ingestion of microplastics by planktonic copepods in nature is very low and therefore planktonic copepods are not relevant vectors of microplastics in marine food webs.

About the PhD defence

Rocío Rodríguez Torres will defend her PhD thesis "Ingestion and effects of microplastics on marine planktonic food webs" on Wednesday 6 April 2022 at 13:00 on Zoom (find link below) and at DTU, Produktionstorvet, 2800 Lyngby in building 421, auditorium 74.


  • Principal supervisor: Professor Torkel Gissel Nielsen, DTU Aqua
  • Co-supervisor: Senior Researcher Rodrigo Almeda, University of Las Palmas de Gran Canaria, Spain
  • Co-supervisor: Senior Researcher Nanna B. Hartmann, DTU Environment


  • Associate Professor Marja Koski, DTU Aqua (chair)
  • Professor Penelope Lindeque, Plymouth Marine Laboratory, UK
  • Professor Ketil Hylland, University of Oslo, Norway 

Chair at defence

  • Senior Researcher Sigrun Jonasdottir, DTU Aqua
Learn more

A popular science summary of the thesis can be downloaded here

A copy of the thesis is available by e-mail on request. Please contact Karin Stubgaard, stub@aqua.dtu.dk.

Link to Zoom and guidelines for online attendance

It is possible to attend Rocío Rodríguez Torres’ defence on Zoom using this link: https://dtudk.zoom.us/j/62512580002

Please, enter the meeting 10 minutes prior to the defence proceedings are scheduled to start. All participants are muted per default, but we ask you to double check that your microphone is turned off at all times.