Meiobenthos and free-living nematodes as tools for biomonitoring environments affected by riverine impact

Abstract

The effects of the human impact on the coastal environments and relative biota can be different and even greater than those derived by natural fluctuations. The major disturbance causes in the coastal systems are rivers that may be important sources of nutrients and pollutants, particularly in a semi-closed basin such as the Adriatic Sea. In this context, we investigated the distribution of both meiobenthic and nematode assemblages in the Central Adriatic Sea to evaluate whether and how they are influenced by riverine discharges and which faunal descriptors are the most effective in detecting this type of stress. On the basis of our results, the disturbance effects in the studied area might be caused by both local streams and Po plume, and even if the latter might be considered of lesser extent, it is worthy to note its real impact at a short distance from the coastline. Meiobenthic assemblage structure appears as a good tool for detecting short-term responses of the benthic domain, whereas nematode assemblages seem more useful for defining long-term responses. Accordingly, the former highlighted from poor to sufficient ecological quality status (EQS) of this area, whereas the latter from moderate to bad EQS. Life strategy traits prove to be the most informative faunal descriptor due to their high correspondence with the environmental variables and particularly with this type of disturbance.

Nematode biodiversity and benthic trophic state are simple tools for the assessment of the environmental quality in coastal marine ecosystems

“…For example, at Falconara, characterized by the lowest levels of trophic status and of biodiversity, some indicators of ecological quality status (c-p and ITD) give "moderate" or even "good" assessment in few sampling times (Table 8B). Such discrepancies suggest the need of combined simultaneous use of a wide range of ecological indicators, coupled with indicators of trophic status, in order to achieve a reliable environmental assessment (Semprucci et al, 2015a;2015b;Chen et al, 2018).…”

“…Due to these characteristics, they have been utilised as indicators of a plethora of different environmental disturbances (Danovaro and Gambi, 2002;Steyaert et al, 2007;Moreno et al, 2008Moreno et al, , 2011Neher and Darby, 2009;Mirto et al, 2014;Pusceddu et al, 2014a;Hannachi et al, 2016): they, for example, are sensitive to hydrocarbon contamination (Danovaro et al, 1995;Mahmoudi et al, 2005;Losi et al, 6 2013) and organic enrichment (Essink and Keidel, 1998;Fraschetti et al, 2006;Moreno et al, 2008;Gambi et al, 2009), including biodeposition from aquaculture activities (Duplisea and Hargrave, 1996;Mazzola et al, 2000;Mirto et al, 2002;Vezzulli et al, 2008). In particular, previous studies have reported that the amount and the nutritional quality of sedimentary organic matter may affect nematodes biodiversity, and more specifically their taxonomic composition (Moreno et al, 2008;2015a;2015b;Bianchelli et al, 2016b).…”

The early catfish catches the worm: predation of Corydoras aeneus (Siluriformes, Callichthyidae) on freshwater nematodes

“…Nematodes usually dominate in heavily polluted bottoms (e.g. Coull and Chandler, 1992;Heininger et al, 2007), and contrary to chironomids, their life-cycle is fully benthic, which implies that the structure of nematode species assemblages can be a relevant indication of both short-and long-term contaminations (Höss et al, 2011;Semprucci et al, 2015;Haegerbaeumer et al, 2017). Fish-nematode feeding studies can be performed under various specific abiotic and biotic conditions and provide coherent measures of feeding rates (see e.g.…”

Do separated taxa react differently to a long-term salinity increase? The meiobenthos changes in Bay Sivash, largest hypersaline lagoon worldwide

“…There is no doubt that changes in the structure of the meiobenthos affect the functioning of other components of aquatic ecosystems (Mokievsky, 2009;Carugati et al, 2018). Therefore, the meiobenthos can be one of the most effective bioindicators of an aquatic environment state (Gyedu-Ababio and Baird, 2006;Moreno et al, 2008;Riera et al, 2011;Alves et al, 2013;Semprucci et al, 2015;Zeppilli et al, 2018;Carugati et al, 2018). The meiobenthos may supply information of great bioindication interest not only due to its valuable role in marine food chains but also due to its ecological characteristics (small size of animals, high abundance, high generation rates and sensitivity to variations in environmental situation).…”