SEARCH

SEARCH BY CITATION

‘Marine Ecosystems and global changes’ is a highly topical work, especially coming after last year's long hot summer in Europe. Edited by Manuel Barange, John G. Field, Roger P. Harris, Eileen E. Hofmann, R. Ian Perry, and Francisco E. Werner, this book is a summary of a decade of research involving a large number of scientists who participated in the GLOBEC project (Global Ocean Ecosystem Dynamics project). GLOBEC involved the national programmes of many countries, regional programmes and multinational programmes, and had many sponsors. It sought to fill the gaps in our knowledge regarding the variability of ocean ecosystems, the dynamics of which are still largely unknown. The objective of the book is to explore what has been learned about the fundamental dynamics of marine ecosystems and the response to anthropogenic changes, including climate change and overexploitation, as well as natural variability.

Climate change is affecting the entire planet, causing profound shifts in marine ecosystems. In this context, the human impact has been so intense that since 1950 a new geological era, the Anthropocene, has been recognised: the Earth is now entering its sixth major extinction event. Global changes comprise a range of problems such as climate change, biodiversity loss, and decreasing water resources, which until now have always been considered separately, both from each other and from the human activities that drive them. Obviously, human pressure on marine resources has also increased. Although historically there has always been a tendency to separate natural climate variability from exploitation patterns, there is an emerging awareness that climate and anthropogenic factors interact. Understanding climate variability and its impact on marine ecosystems has become the main goal of current research.

The GLOBEC researchers are guided by a new way of looking at marine ecosystems that considers the ocean from a more holistic standpoint. This approach was facilitated in the 1980s by the development of new technologies. Indeed, whereas in the 1970s most oceanographic research had been conducted from an intradisciplinary perspective, in which studies tended to be descriptive and limited in space and time, the subsequent availability of satellites and computers facilitated integrated studies on the basin scale and enabled the processing of huge amounts of data. This technology also enhanced cooperation, enabling scientists to work in a more coordinated way.

In recent times, anthropogenic forcing has accelerated; causing significant problems, among them increased production of greenhouse gases, which enhance climate change. Many of the questions that have arisen, such as the role of phytoplankton in the carbon cycle, the influence of pollutants on ecosystems, and the variability of fish stocks, cannot be addressed without a better understanding of the dynamics of plankton, which are also heavily affected by anthropogenic forcing. All these issues relate to the causal relationship between forcing variables and the structure and functioning of oceanic ecosystems.

In the introduction, with reference to the role of oceans in the Earth's system, the authors stress the importance of water to our planet, even suggesting that Water would be more a more appropriate name for it than Earth! They point out that marine ecosystems fluctuate on a multitude of time scales due to a combination of climate variables. The complexity of forcing factors and pathways makes it difficult to establish a connection between climate and ecological responses, which include both direct and indirect effects. Changes include both simple ecological responses occurring soon after an extreme climate event and alterations resulting in linear and non-linear responses on decadal, multi-decadal and multi-centennial time scales. Climate change has had and will continue to have profound consequences for marine ecosystems. This is because ocean warming will result in increased vertical stratification, reduced vertical mixing and nutrient supply, and thus lower productivity with large regional differences. These consequences go hand in hand with those already being observed, such as changes in species composition, seasonality and distribution.

The ultimate goal of GLOBEC's research is to support sustainable marine ecosystem management. This is based on the recognition that marine ecosystems are critical for global food security and for sustaining the well-being of many national economies, particularly those of developing countries. The trend in natural resource depletion should be reversed by implementing strategies including targets to protect ecosystems and the integrated management of living resources. These strategies require an adequate understanding of marine ecosystems and their response to climate change and other anthropogenic forcing factors. As a policy requirement, marine management needs to be guided by across-sector, interdisciplinary and science-based approaches, clarifying its local, regional, and global impacts. Any attempts to achieve sustainability require us to learn how to live with and adapt to global change. We must also recognise and live within the biophysical limits of the Earth's system.

The book is divided into four sections. Part one describes climatic forcing and human impact. Part two deals with our current understanding of the structure and functioning of marine ecosystems, as based on observation and experimentation; it describes the ecological processes that determine ecosystem structure. It also discusses the concept of target species, which is a means of developing cross-regional comparative studies via the modelling of population dynamics, coupling biological and physical factors.

Part three tackles the complex relationship between marine ecosystems and human society, referencing the need to incorporate social sciences in our attempts to understand this interaction (the human dimensions of changes in marine ecosystems). An overview of how management needs to be changed is also provided, describing convergence between ecosystem science and ecosystem management concerning the need for an ecosystem-based approach to fisheries management.

Part four discusses the difficulties and the state-of-the-art in predicting ocean ecosystem responses to future global change scenarios, addressing the limitations and uncertainties of these predictions. The final chapter summarises the contributions of the GLOBEC approach to marine ecosystem research. It identifies gaps in our knowledge and future research directions.

The book aims to establish the baseline scientific knowledge for a new generation of researchers and managers and provides good reading material for young scientists. It reflects the state-of-the-art, the arguments are developed in a highly specialised way, and the chapters, despite being written by various scientists, are logically connected and unified.