WO2011135122A1 - Benthic cage for polychaete annelids - Google Patents

Abstract

The invention relates to a benthic cage for polychaete annelids, designed to allow the use of these organisms in in situ studies of the quality of marine and estuarine sediments and dredged material exposed to different sources of contamination, including both chronic (inter alia maritime traffic, urban and industrial waste water effluents, surface run-off and infiltration water from agricultural and livestock operations) and acute contamination. The invention consists of a structure formed by a horizontally positioned container, the ends of which are sealed with two stacked permeable meshes that allow the free circulation of water and sediment through the device, while preventing the organisms from leaving the receptacle and being preyed upon by other species. The stiffness and strength of the PVC allow the sediment or dredged material being studied to be introduced into, and retained inside the cage, thereby allowing the organisms to be directly exposed to same.

Description

 BENTONIC CAGE FOR ANÉLIDOS POLYQUETOS SECTOR DE LA TÉCNICA. The benthic cage for polychaete annelids is aimed at the study of quality

(Ecotoxicology; Development of quality guides) of contaminated sediments and dredged material, using in situ bioassays with polychaete species.

Its design allows direct exposure of organisms to contaminated material and prevents them from escaping or being preyed upon by other species in the environment.

This type of on-site exposure design allows the evaluation of the toxicity of contaminated sediments under natural conditions where the physical, chemical and biological variables can affect the bioavailability of pollutants, assuming a significant advantage over the toxicity tests that are develop in the laboratory under controlled conditions.

STATE OF THE TECHNIQUE.

Sediments play a fundamental role in the marine system. They are the habitat of more than 90% of the species found in the ocean and constitute the food base of many organisms. They also have the ability to retain pollutants from the continents and the water column. The ecological relevance of sediments along with their role as a contaminant store make studies of sediment quality a good tool for assessing the quality of marine ecosystems. These types of studies are equally applicable to dredged materials, being a crucial part in their management {Ramos-Gómez J, Martín-Díaz ML, DelValls TA. 2009. Acute toxicity measured in the amphipod Ampelisca brevicornis after exposure to contaminated sediments from Spanish littoral. Ecotoxicology 18 (8): 1068-76). Toxicity bioassays in which benthic biota is exposed to contaminated sediments and dredged material are considered an appropriate tool to assess their quality (DelValls TA. 2007. Design of integrated pollution assessment models and their effects on marine and coastal systems and human health .: Ministry of the Presidency Center for the Prevention and Fight against Maritime and Coastal Pollution (CEPRECO) -Serie Investigación, Madrid) and the state of environmental health of marine ecosystems.

The different toxicity bioassays and the different variables that are analyzed at the individual, cellular or / and molecular level allow not only to determine if the pollutants are in the abiotic section of the ecosystem, but also to assess their bioavailability and reversible adverse effects. or irreversible that they can produce in biota. Ultimately, toxicity bioassays constitute a primary tool in the evaluation of the environmental quality of sediment / dredging material, as well as an important source of information regarding the risk to the ecosystem and human health that can be assumed by contaminants present in these matrices.

The bioassays that have been most profusely used for the evaluation of the quality of sediments and dredged material have been of two types: laboratory tests and tests focused on the study of organisms native to the study area. However, these methodologies have a number of drawbacks. On the one hand, laboratory tests are carried out under strictly controlled physical-chemical conditions, so the results they offer do not allow reliable predictions of the potential effects that may occur in the field, where the variability is very high. On the other hand, studies focused on the analysis of native organisms can lead to erroneous conclusions if these organisms have developed adaptations to the environment or if dredging operations have altered the system so much that they have prevented the development of native populations. Avoiding these disadvantages, in the last years a new methodology has begun to be developed: the use of non-established native organisms. These bioassays also act as a way of integrating the results that can be obtained through laboratory tests and field tests (Martín-Díaz ML, Blasco J, Sales D, DelValls A. 2004. Biomarkers as tools to assess sediment quality. Laboratory andfields surveys. Trends Analyt Chem 23 (10-11): 807-818).

Polychaetes are a key group within the benthic communities of coastal and estuarine sediments and represent a significant proportion of the total biomass of invertebrates in these systems (Casado-Martínez MC, Smith BD, DelValls TA, Luoma SN, Rainbow PS (2009 Biodynamic modeling and the prediction of accumulated trace metal concentrations in the polychaete Arenicola marina. Environ Pollut 157 (10): 2743-2750). They are the food source of many predators, so they act as a gateway for contaminants in the food chain. In addition, polychaetes have a high tolerance to a wide variety of toxins, which makes them the most abundant invertebrates in contaminated areas (Sandrini JZ, Lima JV, Regoli F, Fattorini D, Notti A, Marins LF, Monserrat JM. 2008 Antioxidant responses in the nereid Laeonereis acuta (Annelida, Polychaeta) alter cadmium exppsure Ecotoxicol Environ Saf 70 (1): 115-120). These characteristics make this taxonomic group a good indicator of the quality of benthic systems and its use in pollution monitoring is widespread (Sandrini JZ, Lima JV, Regoli F, Fattorini D, Notti A, Marins LF, Monserrat JM (2008) Antioxidant responses in the nereidid Laeonereis acuta (Annelida, Polychaeta) after cadmium exposure Ecotoxicol Environ Saf 70 (1): 115-120).

However, the use of polychaetes in situ is a tool still to be explored. Given the importance and the proven validity of these organisms as indicators as well as the advantages of such tests, the use of benthic cages for polychaetes can provide new information a new approach in the risk assessment that contaminated sediments and dredged material can have about biota.

EXPLANATION OF THE INVENTION The benthic cage that is presented is designed for the exclusive use of polychaete annelid species as bioindicators of the quality of marine sediments and dredging material in bioassays in situ, allowing direct exposure of organisms to study material and the natural conditions of the environment. This type of bioassay will make possible a better understanding of the toxicity processes that the contaminated material triggers in the polychaetes under natural conditions and will allow more accurate predictions of the potential effects that sediment and dredging material pollution causes in the biota of the coastal systems, from polychaetes to higher levels of the food chain.

The use of polychaete organisms in toxicity studies is a widely used practice due to the advantages that these organisms present: they are easy to identify, abundant, have a relatively long life, are available for much of the year, are resistant to handling during bioassays, tolerate variations of physical-chemical parameters such as salinity and are sensitive to contamination, to which they respond, for example, by accumulating potentially toxic substances (metals and organic compounds) and activating antioxidant and detoxification metabolism (biomarkers).

However, the application of these organisms in bioassays in situ is a field that has not been explored to date, and that, however, can provide new and valuable information about the responses of polychaetes to sediment contamination and dredging material under natural conditions, significantly improving the knowledge and relevance of these organisms as environmental bioindicators.

Although there are currently benthic devices for monitoring the quality of aquatic systems, these are aimed at the study of water pollution, not sediment, and its design does not contemplate the possibility of the use of polychaetes, but is focused on swimming species and of greater size or of little flexibility, since it does not take into account the ability of some polychaetes to extend their body, thereby reducing their diameter, which allows them to escape through holes much narrower than their body in normal state. The cage we present has a specific purpose and its design covers the specific requirements that the use of polychaete species demands. It allows the direct exposure of organisms to sediment and / or dredged material under natural conditions while they remain confined without the possibility of escape, so that continued exposure is ensured and tracked individuals can be monitored throughout the bioassay. and periodic sampling.

The cage structure makes it resistant to sediment weight, its size allows easy handling as well as its use in diverse coastal systems, from deep areas to shallow estuaries.

Its simplicity, on the other hand, converts the benthic cage for polychaete annelids into an easily reproducible device.

DESCRIPTION OF THE ILLUSTRATIONS.

For a better understanding of the invention, illustrations of it and its constituent elements are presented below. Figure 1. Perspective view of the benthic cage for polychaete annelids.

 10.- Cylindrical tube, which constitutes the rigid structure of the cage.

 13. - Metal upper clamps to hold permeable meshes.

 14. - Metal bottom clamps to hold permeable meshes.

 16 and 17.- Screw and nut for clamping upper and lower clamps.

 18.- Threaded hole in the lower clamp.

 19. - Threaded bar to hold the cage on the sediment.

 20. - Entrance hole to the cage.

 21. - Mesh that surrounds the entrance of the cage.

22. - Mesh joint (21) with outer mesh (11). Figure 2. Elements that make up the benthic cage and its assembly.

 10. - Cylindrical tube, which constitutes the rigid structure of the cage.

 11. - External mesh that exerts a protective function with respect to the mesh (12).

12. - Internal mesh that prevents organisms from escaping

 13.- Metal upper clamps to hold permeable meshes.

 14. - Metal bottom clamps to hold permeable meshes.

 15. - Crafts in the clamps for joining the upper and lower clamps

 16 and 17.- Screw and nut for clamping upper and lower clamps.

 18.- Threaded hole in the lower clamp.

 19.- Threaded bar to hold the cage on the sediment.

Figure 3. Access of the benthic cage and closing device.

 13.- Metal upper clamps to hold permeable meshes.

 16 and 17.- Screw and nut for clamping upper and lower clamps.

 20. - Entrance hole to the cage.

 21. - Mesh that surrounds the entrance of the cage.

 22. - Mesh joint (21) with outer mesh (11).

 23. - Flange for blocking the exit of the cage.

MODE OF EMBODIMENT OF THE INVENTION.

The assembly of the benthic cage for polychaete annelids (Figure 1) can be seen in Figure 2. The cage consists of a container, which can be of cylindrical type of PVC (10) of 30 cm in diameter and a height that can vary between 30 and 40 cm for greater functionality. Each cylinder base is sealed with two overlapping permeable meshes. The outer mesh (11), which exerts a protective function with respect to the other mesh, is 5 mm in light. The inner mesh (12), which prevents organisms from escaping, has 1 mm of light. Both meshes are attached to the bases of the PVC pipe by means of 2 metal clamps (13, 14), which are joined together through the holes they present at each end (15) by inserting a screw (16) secured with a nut (17). The lower clamp (14) has a nut hole (18) of 5 mm in diameter to which a thread bar (19) of 20 cm length is screwed. These bars are stuck in the sediment as an anchor, securing the cage in position while the bioassay lasts in situ.

The cage opening device can be seen in Figure 3. The cage door is established by practicing a hole (20) of approximately 10x10 cm in the meshes of one of the bases of the cylinder, through which the sediment will be introduced and the organisms and the biological samples will be extracted during the bioassay. The perimeter of the hole is surrounded with a mesh (21) of 1 mm of light, which joins the previous ones either with tanza wire or with plastic flanges (22). The mesh (21) blocks the exit once it is knotted with the help of one or more flanges (23). This closure system facilitates and speeds up the sampling during the course of the bioassay.

Claims

Bentonic cage for polychaete annelids, comprising a structure formed by a container, whose ends are sealed with two superimposed permeable meshes that allow the free circulation of water and sediment through the device, while preventing organisms from leaving the receptacle and that are predated by other species, attached to the ends of the container by means of clamps, divided into two parts, upper and lower joined by thyme and nut, the lower clamps containing an inner thread in which two threaded stems are screwed vertically, whose mission is keep the cage fixed horizontally on the seabed. Bentonic cage for polychaete annelids, according to claim 1, characterized in that the outer mesh of the ends of the cylinder exerts a protective function with respect to the inner mesh, whose mission is to prevent organisms from escaping. Bentonic cage for polychaete annelids, according to claims 1 and 2, characterized in that the introduction of the organisms in the cage is carried out through a hole made in the two meshes of one of the bases of the cylinder, whose perimeter is surrounded with another mesh, which joins them forming a cylindrical sleeve, said seam or any other type of union being able to be used, and the closure of which can be practiced by means of one or more flanges. Use of the bentonic cage for polychaete annelids, for the on-site evaluation of the toxicity of contaminated sediments, allowing the direct and prolonged exposure of organisms to contaminated material under natural conditions where physical, chemical and biological variables can affect the bioavailability of pollutants