we rebuild coral reefs

our team

We are a young and innovative organization based in Zürich. As an ETH Spin-off, our work is grounded in science and engineering, and elevated by art and education.
rrreefs association was founded in October 2020 by Marie Griesmar, Ulrike Pfreundt, and Hanna Kuhfuß, joined by Josephine a few months later.
In 2023, rrreefs became a social environmental impact business.

Dr. Ulrike Pfreundt

Co-Founder, Head of Science and Development

Dr. Ulrike Pfreundt

Ulrike is an expert in tropical ocean ecosystems, with a PhD in Microbial Oceanography and Genetics. She has developed and led scientific projects in the lab and in the field for more than 10 years. At rrreefs, Ulrike is responsible for scientific strategy and business development.

Marie Griesmar

Co-Founder, Head of Product & Marketing

Marie Griesmar

Marie is an artist and material specialist, whose artistic research and practice have been focused on aquatic ecology for more than 8 years. She understands the behavior of clay like no other and ensures that the design of our system fits its purpose. At rrreefs, Marie leads product development and design, marketing, and public relations.

Hanna Kuhfuss

Co-Founder, Head of Field Operations and Scientific Partnership

Hanna Kuhfuss

Hanna is a marine scientist who worked for different green and social start-ups and NGOs in the field of ecosystem protection and applied marine sciences. As an advanced scientific diver with over 11 years experience in ecosystem conservation and restoration, Hanna leads our field operations. She is responsible for safety underwater and our scientific field and lab experiments.

Josephine Graf

Co-Founder, Head of Business Development

Josephine Graf

Josephine has a background in International Relations with a focus on climate politics. Having worked both in the private and public sector, she has gained first-hand insights into sustainability consulting and international cooperation. At rrreefs, Josephine is driving partnership engagement and business development opportunities.

Mauro Bischoff

Designer & Field Operator

Mauro Bischoff

Mauro is designer and a dive instructor. He has a passion for new challenges and building tools. At rrreefs, he is responsible for creating solutions for each reef implementations, technically and logistically.

our values


Passion for the ocean unites us as a team, and drives us to be our best every day. We are determined to reach a massive positive impact for the oceans, the planet, and human societies.


At the core of our initiative lie respect and empathy for nature and all living beings. We strive to create a healthy, caring, and appreciative working environment, open to everyone regardless of gender, beliefs, or ethnicity.


Embracing a ‘no-bullshit’ philosophy, we refuse to make false promises. Honesty and transparency are key to our communication.


We are guided by curiosity, critical thinking, and the pursuit of new challenges, while adhering to scientific standards and high quality of work.

our volunteers and students

We are supported by a group of brilliant volunteers and students who are taking a lot of work from our shoulders and contributing to rrreefs in many meaningful ways.

Emilia Lendi


Cassandre Wuarchoz

Scientific visualization illustrator

Daniela Guedes

Newsletter redactor

Olivia Götschi

Communication specialist

Sophie Rhyner

Instagram specialist

Lara Land

Brick monitoring specialist

Salomé Stauffer

rrreefs educator

Leïla Tazi

Underwater photographer

Jonas Ward Van den Bulcke

Brick programmer

Céline Arnould

Graphic designer

Luisa Meiritz

Marine Biogeochemist

Sara Gagliardi

Fish expert

Federico Zanini

Film director

Leony Malthaner

Marine all-rounder

Yannick Krijnen

Film Director

past volunteers and alumni

  • Franziska Trummer, 2022-2023, Fish redactor

  • Sarah Zbinden , 2020-2022, Community manager

  • Mariana Henud, 2021, Instagram specialist

  • Andrin Fontana, 2021, our all-rounder building specialist

  • Lorena Oberlin, 2021, making clay balls like no one

  • Vera Jud, 2021, the clay balls champion

  • Deborah Egger, 2021, studio helper

  • Simon Renfer, 2020, rendering master

  • Vera Kobler, 2020, graphic designer

  • Elia Küenzi, 2020-2021, chef of the clay preparation

Our clients, business partners and employees are thrilled with our collaboration with rrreefs –
a strong, passionate team and an innovative and scalable approach to healthy reefs and oceans.

Dr. Carsten Schildknecht, CEO Zurich Group Germany

our advisory board

We are grateful to be advised by this incredible team of experts.

Dr. Phanor Montoya-Maya

Director of Corales de Paz, Colombia

Prof. Roman Stocker

Professor of Environmental Engineering at Swiss Federal Institute of Technology Zurich, Switzerland

Jasmin Khalifa

Founder and Principal Consultant at guidance4good, Switzerland

Stephan Hillert

Global Head of Distribution, Customer & Growth at Zurich Resilience Solutions, Switzerland

Andreas Feller

Head of Swiss Onshore and Deputy Head of Private Banking at Rothschild & Co, Switzerland

Petra Riga-Müller

Head of Commercial Insurance at Zurich Group, Germany

awards & nominations

Woman for Change by ChangeNOW - Recognition 2023

Extrem Tech Challenge x Katapult Ocean - Finalist 2023

The Earthshot Prize, Revive our Ocean - Nominee 2023

Kultur-Kreativpilot*innen - Winner 2022

Falling Walls Berlin - Finalist 2022

Planet Hero Award 2021 - Winner

Hochparterre ‘Die Besten 2021’ – Design Award Gold

SEIF Tech for Impact – Audience Award 2021

SEIF Tech for Impact – Future Impact Trend Award 2021


Bild der Frau

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Migros Magazine

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Schweizer Familie

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Sonntags Blick

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SRF Gesichter & Geschichten

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SRF Tagesschau

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Drôle d’époque – RTS1

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France 24

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Migros Magazin

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Der Bund

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Government of the Virgin Islands, Press Release

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ARD Tagesthemen

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