THEME 2
Our fragile coasts
outstanding issues
Wadden systems, either or not as part of deltas, are located at the physical intersection between terrestrial and marine environments. The Netherlands, for example, is in post-glacial times shaped through the interplays of wind, land and sea, rivers, and brackish deltas, the Wadden Sea and North Sea systems, and human activities. Coastal zones face questions regarding climate and anthropogenic influences, sea level rise and resilience to these changes, and how these changes in turn impact the humans inhabiting these areas both in the Netherlands, in other parts of the Kingdom (e.g., the Caribbean), and globally. NIOZ performs scientific research that improves our understanding of the ecology of marine and estuarine systems and that answers the questions about how humans affect these environments. Seen in this light, coasts and deltas represent an active front line and are highly sensitive in the face of changing conditions, heavy exploitation, and marine policies. Researchers at NIOZ build insight and understanding of these fragile ecosystems, with research across a range of connected fields from physics to behavioral ecology.
QUESTION 4
How does the interaction between habitats and species communities affect the stability of coastal ecosystems?
Coastal systems including estuaries and deltas form the link between terrestrial and marine habitats and are highly dynamic marine systems. In the physical realm, tidal changes constantly shape and destroy geological and ecological structures, while in the biological realm species utilize but also build and influence such structures, often in specific life-stages. The productivity of resources or prey species depends on the abiotic conditions present in the system. To understand the dynamics of species (such as the commercially interesting flatfish species or e.g., the widely appreciated birdlife), we need to understand how the individual organisms are impacted by their changing abiotic and biotic environment and vice versa. While surrounding conditions influence how organisms can use their environment, some species are able to shape their habitat themselves (ecosystem engineers). Species such as benthic microalgae, mussels, corals, sponges, and salt marsh grasses can enforce positive feedbacks where their presence in the habitat provides structure, and ensure the stabilization of habitat and persistence under changing physical pressures. Such engineering activities facilitate the persistence and coexistence of other species that rely on the biogenic structures. Research focuses on how these feedbacks can arise and remain, and how changing conditions impact the ability of organisms to fulfil these functions for the ecosystem.
QUESTION 5
How do organisms respond and adapt to a changing coastal environment?
The Wadden Sea is a UNESCO heritage site, the Eastern Scheldt a National park. In spite of many levels of formal protection and management, all Dutch coastal systems, including Caribbean coasts, are intensely exploited and impacted by fishing, sand nourishments, protective engineering structures, pollution, dredging, aquaculture and energy production. All these forms of exploitation interact, their potpourri affecting the natural ecosystem processes. NIOZ builds on a long tradition to understand the resilience of individual organisms, as well as of populations, communities, and ecosystems. Salt marshes and macrofauna, such as oysters, shape the landscape by trapping sediment and changing the topography, or by making the sediment sandier or muddier, and they adapt to changes in sea level and sediment supply. Benthic production capacity supports exploitation of harvested species (fish, shrimps, and mussels, for example), but is also the basis for survival and reproduction of higher trophic levels, such as the migrating shorebirds that biotically connect chains of coastal ecosystems including the Wadden Sea and Delta. We study how environmental changes affect the energy flows and ecological processes within the context of trophic interactions, ranging from biogeochemical to species interactions, and ultimately evolution. This research includes both spatial (ranging in scale from millimeters to hundreds of kilometers), and temporal dynamics (ranging from tidal through seasonal to centennial periods). We develop and use multidisciplinary state-of-the-art techniques and equipment, such as spatial surveys, temporary and permanent measurement stations, and numerical modelling.
With our research we aim at a deeper understanding of species interactions and habitat requirements in coastal systems across different levels of ecological organization. That is: to understand environmental effects on individuals (behavior), populations (abundances and adaptations), species (coexistence and diversity), and communities (structure). We explicitly link the patterns at large scales (species communities) with adaptations at small scales (individual organisms), identifying and studying the feedbacks driving their ecological interactions. We explore the possibilities, as well as limitations, of organisms to adapt to environmental change with its effects on population dynamics and community structures. Using empirical data, both from experiments and from long-term data, we study this interplay in detail, over large spatial and temporal scales. The empirical insights work in tight connection with theoretical approaches, predicting and understanding resilience, state shifts, and evolutionary dynamics, which allows a comprehensive understanding of ecological interactions in a changing coastal system.
QUESTION 6
How are coastal marine ecosystems connected?
Coastal areas are linked all over the world, by the seasonal visitation of the shorebirds which migrate between Western Africa and the Arctic. Similarly, many fish species connect different marine regions and even freshwater and marine habitats. Changes in coastal systems, due to natural processes and anthropogenic impacts, require our understanding of food web structure and dynamics, and how such systems are connected biologically and abiotically. NIOZ research pays attention to the connection between intertidal, shallow regions and deeper marine regions through the utilization of these habitats for nursery areas versus spawning areas in fish, for example. More examples can be found in the exploration of shallow and deep oceanic physical processes and dynamics relevant for coastal and deep-sea futures, as well as the sustainable exploitation of the deep. Movement is crucial to almost any ecological and evolutionary process. Studying the key processes affecting movement at different spatial and temporal scales, will generate understanding of how organisms react to environmental change, such as habitat fragmentation, climate change, biological invasions etc. Movement and migration of animals and plants act as important transport routes of nutrients, energy and information, both within and between ecosystems. Long-distance movements and migrations even connect ecosystems on a global scale. As such, moving organisms can carry over ecological effects obtained in one (part of the) system to another.