Wood-destroying marine animals

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Various organisms are referred to as wood-destroying marine animals (also maritime or marine wood destroyers ) whose main habitat is the sea ecosystem and which are able to attack or break down the composite of wood cell walls. The animals use the wooden body as a nutrient and / or nest substrate. They are separated from the wood-destroying fungi and insects by the marine habitat. The animals can cause considerable damage to wooden bodies stored or built under water, with the most severe damage being caused by the various types of marine clams or wooden clams (Teredinidae).

Species overview

In the entire sea ​​there are different wood destroyers from the class of bivalves (Bivalvia), in particular from the families wood borer (Teredinidae) and stone borer ( Pholadidae), as well as the class of crustaceans (Crustacea) with the families wood lice (Limnoriidae), ball isopi (Sphaeromatidae) and Borehole shrimp (Cheluridae) common.

Mussels (Bivalvia)

Crustaceans (Crustacea)

Damage potential and importance

With regard to their harmful effects, the representatives of the mussels and crustaceans differ. For example, the enormous damage potential of the ship's drilling mussel is based on a morphological difference to other mussel species - the greatly reduced mussel shells that have been converted into drilling tools. With these tools they pierce the entire wood body, mainly in the direction of the grain, in order to feed the wood substance that has been shredded into your metabolism. In contrast to this, most crustaceans mainly cause damage close to the surface, although it is currently unclear whether other crustaceans besides the wood lice can break down the structural substances of the wood cell wall and use them physiologically.

In today's shipping, damage caused by wood-destroying marine animals no longer plays a role because wood has long been replaced by other materials. Nevertheless, they are structurally, economically and technically important because wood is still primarily used in water engineering and port construction and for coastal protection in many countries. On the German Baltic Sea coast alone, damage from the ship's drilling mussel has cost around 100 million euros since 1993. There is also a risk to cultural goods such as shipwrecks or sunken settlements. For example, wooden and rock drill clams can completely destroy wooden shipwrecks within 10 years.

Protective measures

The ancient Vikings, Greeks, Romans, Egyptians and Chinese tried to protect their ships against wood-destroying marine animals by treating the boat skin with resins, paints and pitch or by equipping them with a layer of wood (sacrificial wood).

Today there are different approaches to wood protection:

Wood preservatives

The chemical wood protection offers a possibility to increase the individual natural resistance of individual woods against wood-destroying marine animals. The use of z. B. Formerly established products based on creosote or copper-chromium-arsenic has been and is being restricted for ecological reasons.

Wood modification

There is currently very little long-term experience of the effectiveness of different wood modifications in terms of resistance to wood-destroying marine animals. Current studies indicate that only methods of direct cell wall modification are suitable for this.

Natural durability

Damage can be avoided or delayed by using types of wood with the appropriate natural durability . The natural resistance to wood-destroying marine organisms is based on the hardness or density as well as on the stored core constituents of the respective types of wood. However, only tropical wood species such as Angelique ( Dicorynia guianensis ) or Greenheart ( Chlorocardium rodiei) meet these requirements, but their use is controversial for ecological and also economic reasons.

Structural measures

Structural measures, such as the application of an additional (environmentally friendly) protective layer on the wood surface, can make access more difficult for organisms. Current research focuses on special geotextiles , for example .

Individual evidence

  1. ↑ a b c Vera H. Haustein and Tilo Haustein: Wood-destroying sea animals . In: wood protection. Wood science - fungi and insects - constructive and chemical measures - technical rules - practical knowledge . Hanser, 2015, ISBN 978-3-446-44240-5 , pp. 162-164 .
  2. ↑ Uwe Noldt: Wood- destroying and wood- dwelling fungi, insects and marine animals . In: Practical manual for wood protection . Edition: 1 (January 1, 2014). Müller, Rudolf ;, ISBN 978-3-481-02990-6 , p. 149-153 .
  3. ↑ a b c L. MS Borges: Biodegradation of wood exposed in the marine environment: Evaluation of the hazard posed by marine wood-borers in fifteen European sites . In: International Biodeterioration & Biodegradation . tape 96 , December 1, 2014, p. 97-104 , doi : 10.1016 / j.ibiod.2014.10.003 ( sciencedirect.com [accessed December 22, 2016]).
  4. ^ A b Guidelines for Protection of Submerged Wooden Cultural Heritage. 2011, accessed December 21, 2016 .
  5. ↑ Coastal protection: Shipworm eats groynes as soft as butter - WELT. In: THE WORLD. Retrieved December 22, 2016 .
  6. ↑ a b Maritime wood destroyer, stake or shipworm (Teredo navalis). In: www.holzfragen.de. Retrieved December 22, 2016 .
  7. ^ André Klüppel, Simon M. Cragg, Holger Militz, Carsten Mai: Resistance of modified wood to marine borers . In: International Biodeterioration & Biodegradation . tape 104 , October 1, 2015, p. 8-14 , doi : 10.1016 / j.ibiod.2015.05.013 ( sciencedirect.com [accessed December 22, 2016]).
  8. ^ Groyne construction in the coastal protection of Mecklenburg-Western Pomerania. In: www.stalu-mv.de. Retrieved December 22, 2016 .
  9. ↑ DBU - Practical studies on the effectiveness of geotextiles against wood pests in seawater | Area: project database. In: www.dbu.de. Retrieved December 22, 2016 .