Center for Marine Research

On the micro level, Dr. Einat Segev, an interdisciplinary scientist from the Department of Plant and Environmental Sciences, studies coccolithophores, a group of widespread algae that surround their body with tiny platelets made of chalky material. These algae populations grow to enormous numbers and cover thousands of square kilometers in the ocean, and then suddenly die, leaving their chalky shells to sink to the ocean floor. These unique algal relics carry valuable information in their chemistry, environmental information that was ‘recorded’ while the algae were still alive over a time period of millions of years.

Dr. Segev’s group studies these remains, referred to as paleo-proxies, as they serve as indicators for past environmental conditions. Specifically, they look at the bacterial influence on algal paleo-proxies, and how algal-bacterial interactions influence our interpretation of the geological record. By studying how marine bacteria affect the growth, development, and death of these algae, Dr. Segev and her lab are able to read critical clues about ancient climate change – valuable information that can be used to understand the changes our planet is currently undergoing.

Dr. Yael Kiro from the Department of Earth and Planetary Science focuses on historical records to learn about potential effects of climate change. By investigating the geochemistry of terrestrial records, such as lake deposits and accumulations of sediment, her group reconstructs the past climate over the past few hundred thousand years. The insights gained offer an important long-term perspective over a variety of conditions (e.g., atmospheric CO2, radiation, etc.) that can be applied to understanding and ameliorating our current climate crisis.

Dr. Kiro’s research takes her to the Dead Sea region where she is examining thick layers of salt, reflecting extreme aridity in the region, to reconstruct changes in lake levels caused by changes in rainfall. Her group’s findings show the consequences of drying climate and high temperature in the sensitive region of the Middle East, providing important insights into the expected effect of the current warming.

On the macro level, Dr. Rei Chemke, from the Department of Earth and Planetary Sciences, is weaving scientific data and observations into predictive models that can help us prepare for the future. To do so, he combines theoretical understanding of climate mechanisms with observations and state-of-the-art climate models to simulate past, recent, and future climate change. Given that the ocean plays a major part in setting weather patterns, his research also focuses on the ocean’s role in setting the Earth’s past and future climates. To this end, he is working on quantifying and developing a mechanistic understanding of the ocean’s effects on climate during the 20th and 21st centuries.

His work allows him to uncover a new physical understanding of the climate system, which can be used in future studies on past and projected climates. His group has published several papers over the last year showing that the future changes in the climate system are contingent on the response of the ocean to increased greenhouse gasses. In addition, their research has demonstrated that ocean temperature is a key ingredient to warming the Arctic and melting the Arctic sea-ice in recent and coming decades.

Microorganisms are social beings, engaging in a variety of interactions, including competition, cooperation, and communication, which profoundly impact both the microorganisms themselves and their surrounding environment. In marine ecosystems, the interactions between microalgae and heterotrophic bacteria play a crucial role in shaping nutrient fluxes and the long-term burial of biogenic material in the ocean. These interactions have persisted for countless millennia, contributing to the dynamic balance of marine environments.

To gain a deeper understanding of the mechanisms driving algal-bacterial interactions and their environmental implications, Dr. Einat Segev’s research group employs tailored model systems. Through the study of these model systems, we can uncover molecular and genetic aspects of algal-bacterial ecophysiology. These model systems facilitate interdisciplinary research at the intersection of microbiology and Earth sciences. They offer valuable opportunities to investigate both present and past environments, enabling us to gain predictive insights into future scenarios, particularly in the context of climate change.

As members of the Tara Expedition—an international environmental research vessel – Prof. Assaf Vardi from the Department of Plant and Environmental Sciences and Prof. Ilan Koren from the Department of Earth and Planetary Sciences analyze samples gathered during successive voyages to study aerosols, specs of matter contained in the samples. Their in-depth studies have revealed significant amounts of microplastics—fragmentary remains of human-generated plastic pollution. These findings demonstrate how near-ocean emissions facilitate the transport of microplastics from the shoreline to the deep ocean, where they affect marine ecosystems, disrupt food chains, and—eventually—harm human health.

They are also investigating the movement of bacteria and viruses from the ocean to the surrounding atmosphere via wind currents to new ecosystems, where they can infect new hosts. Prof. Koren and Prof. Vardi, together with their research teams, compare the microbiome of the air to that of the sea, specifically during algal blooms, and study the connection between them, in order to understand the impact of climate change on ocean-atmosphere feedback.

A central focus of the Marine Center is creating highly sensitive tools to measure the current state of the Earth in order to form benchmarks for measuring change and finding nature-based solutions. Prof. Ron Milo, a leading researcher in environmental sustainability from the Department of Plant and Environmental Sciences, measures biodiversity on the global scale to gain a holistic picture of how humans are shaping the Earth.

This information is essential for forming a baseline of human impact in order to detect changes and deliver nature-based solutions. For example, he found that the sea contributes a disproportionately large fraction of animal biomass, as well as productivity through the photosynthetic organisms. These organisms, low in mass but characterized by rapid turnover, consume as much greenhouse gases as terrestrial plants, and release as much oxygen into the atmosphere. His quantitative analyses provide insights into the delicate balance that exists between marine life forms and the Earth’s atmosphere and serve as important benchmarks for designing strategies to preserve that balance for future generations.