Migrating is not enough for modern planktonic foraminifera in a changing ocean

Abstract

Planktonic foraminifera are single-celled organisms that form a crucial part of the marine food chain. However, little is known about how these organisms' geographical ranges will shift and cope with projected future climate conditions.

Introduction

Foraminifera are microscopic, single-celled organisms that live in the ocean. Their hard outer shells, or tests, are abundant in marine sediments and make them excellent indicators of past environmental conditions, including temperature and salinity. With a long evolutionary history and excellent fossil record, foraminifera have been indispensable in reconstructing paleoenvironmental conditions and studying paleoclimate changes.

In recent decades, the increasing availability of computational power and advanced statistical approaches in analyzing species distribution has facilitated modeling species' geographical ranges for better understanding their responses to environmental changes. Species distribution modeling (SDM) forms the backbone of ecological niche modeling and has become a powerful tool for predicting the potential geographic distribution of a species under current and future climate conditions.

Changing ocean conditions

The increasing greenhouse gas emissions in the atmosphere lead to various consequences in the ocean. Rising levels of atmospheric CO2 cause the "ocean acidification," a reduction in seawater pH, that has been a major concern for marine organisms.

Another outcome of increasing greenhouse gases in the atmosphere is global warming. The warming climate leads to melting of polar ice caps and glaciers, resulting in a potential rise in sea level.

Impacts on Foraminifera

Studies on foraminifera have shown that acidification negatively impacts their physiology and reproduction. Reduced ocean pH impairs the ability of foraminifera to build their tests. Acidic conditions weaken the structure of their tests, making them more vulnerable to physical impacts and increasing their susceptibility to predators.

Rising temperatures, on the other hand, have different effects on different species. Some species may expand their geographical ranges toward the poles, while others may see a reduction in their distribution area. The warming temperature can also affect food availability for foraminifera, such as phytoplankton and zooplankton.

How foraminifera respond to climate change remains an area of active research. However, it is evident that these organisms face a significant challenge in the changing ocean conditions.

Conclusion

Climate change is a significant concern for all living organisms, including planktonic foraminifera. The changing ocean conditions, including acidification, warming, and sea-level rise, pose challenges to foraminifera's survival and distribution. Understanding the impacts of climate change on these organisms is critical for predicting future changes in marine ecosystems

Foraminifera's role in the marine food chain and their sensitivity to climate change make them crucial for understanding the broader implications of climate change on marine ecosystems.