Optimisation of sand nourishment techniques for restoring ecological valuable tidal flats:Unravelling the importance of bio-physical interactions (outside HZ)

Versie van 7 jun 2016 om 14:24

Sand nourishments are widely used in the coastal environment and have been developed to protect the coast and its ecosystems from erosion and sea level rise. Nowadays mega-nourishments are also being used to restore and maintain valuable ecosystems on tidal flats. The latter requires the nourishment practices to be optimized for being eco-friendly.

It is well-known that the presence / absence of soil animals can have a large effect on the erodibility of sediment. Dumping sediment on an existing tidal flat might directly affect the local communities living in these areas by killing them. Moreover, the sediment used for the nourishment of coastal areas is usually deprived of any living organisms, and thus might alter the bio-physical interactions relative to the originally present sediment or facilitate the establishment of invasive species. There is need to gain a generic mechanistic understanding on (1) how benthic communities may affect the long-term development of sand nourishment, (2) how benthic communities respond to different sand nourishment techniques and (3) how this type of measures may be translated to ecosystem services.

Student opportunities:

A way to examine the effects of soil animals on the erodibility of sediment is to compare the properties of sediment with and without benthos. To do so, a large “defaunation” (soil animals removed) experiment has been implemented in the Schelde estuary and will be monitored monthly over the Summer 2016. This experiment is part of a pilot study relative to the Roggenplaat. Environmental data and benthos samples will be collected and measured to answer the following sub-questions:

1)      Benthic community recovery along an elevation gradient at two sites differing in their hydrodynamic exposure

For this project, the student will investigate the influence of elevation, i.e. a proxy for the height of sand nourishment, on the rate of recovery of benthic communities and on abiotic variables (sediment type and properties, hydrodynamic conditions, primary production, etc.) after defaunation. The student will actively participate in fieldwork and analyse benthos samples in the laboratory.

Research type: Field research, Laboratory research

Research level: bachelor

Prerequisite: interest in morphology, ecology

Period: Semester 1, 2016-2017

Contact: Laura Soissons, laura.soissons@nioz.nl

2)      The facilitative effect of ‘priming’ on benthic community recovery

After defaunation, used to mimic the effect of sand nourishment, some areas will be ‘primed’, by adding a known-density of specific benthos species or directly by dumping fresh sediment on top. This project will investigate the potential facilitative effect of such techniques for benthic community recovery by comparing them. The student will actively participate in fieldwork and analyse benthos samples in the laboratory.

Research type: Field research, Laboratory research

Research level: bachelor

Prerequisite: interest in morphology, ecology

Period: Semester 1, 2016-2017

Contact: Laura Soissons, laura.soissons@nioz.nl

3)      Sand nourishments in coastal systems: an Ecosystem-based approach (Literature research)

Benthic communities are highly important for the stability of coastal environment, for the ecosystem services they provide. This project, through a literature research, aims at understanding the influence of sand nourishments on benthic communities in different coastal systems and how it translates to a lack vs. gain of ecosystem services. The student will investigate the literature for studies on sand nourishment, their effect on benthic communities and bio-physical interactions and to address their potential effect on the ecosystem services provided by benthic communities in coastal ecosystems.

Research type: Literature research

Research level: bachelor to master

Prerequisite: interest in morphology, ecology

Period: Semester 1, 2016-2017

Contact: Laura Soissons, laura.soissons@nioz.nl

4)      The influence of living organisms on sediment erosion

The presence of benthic organisms is highly important for the stability of the coast, which might play an important role for the long-term development of sand nourishments. By means of a flume study, using a newly developed field flume, this project will investigate how benthic organisms in different conditions affect the erodability or stability of tidal flats. The student will actively participate in fieldwork.

Research type: Field research, Flume research

Research level: bachelor or master

Prerequisite: interest in morphology, ecology, hydrodynamics

Period: Semester 1, 2016-2017

Contact: Laura Soissons, laura.soissons@nioz.nl

Project summary

Optimisation of sand nourishment techniques for restoring ecological valuable tidal flats: Unravelling the importance of bio-physical interactions

Project results and process

Results:

• Optimisation of sand nourishment techniques for restoring ecological valuable tidal flats:

Unravelling the importance of bio-physical interactions (outside HZ) - results

Description and evaluation of the process:

• Optimisation of sand nourishment techniques for restoring ecological valuable tidal flats:

Unravelling the importance of bio-physical interactions (outside HZ) - process

Sub projects