Artificial soft sediment resuspension and high density opportunistic macroalgal mat fragmentation as method for increasing sediment zoobenthic assemblage diversity in a eutrophic lagoon

Long-Term Dynamic in Nutrients, Chlorophyll a, and Water Quality Parameters in a Coastal Lagoon During a Process of Eutrophication for Decades, a Sudden Break and a Relatively Rapid Recovery

“…This makes eutrophication and dystrophic crises common threats in coastal lagoons, as widely described in literature (Amanieu et al, 1975;Boutiere et al, 1982;Reyes and Merino, 1991;Ferrari et al, 1993;Sfriso et al, 1995;Boynton et al, 1996;Viaroli et al, 1996Viaroli et al, , 2008Viaroli et al, , 2015Giordani et al, 1997Giordani et al, , 2009Guyoneaud et al, 1998;Taylor et al, 1999;Bachelet et al, 2000;Lenzi et al, 2003Lenzi et al, , 2010Newton et al, 2003;Sakka Hlaili et al, 2007;Specchiulli et al, 2009;Giusti et al, 2010;Solidoro et al, 2010;Facca et al, 2014;Kralj et al, 2016;Leruste et al, 2016;Martelloni et al, 2016;Rodríguez-Gallego et al, 2017;Vybernaite-Lubiene et al, 2017;Ménesguen and Lacroix, 2018).…”

Growth and physiological features of Chaetomorpha linum (Müller) Kütz. in high density mats

“…Such threshold must be determined carefully, yet it will represent a significant proportion of the primary production and this may seriously restrict the feasibility of these operations, without mentioning the cost of disposal, that must be borne when the harvested biomass are not suitable for industrial processing. Sediment resuspension and mat stirring, which eventually will cause also the fragmentation of the thalli, may be effective in containing the overgrowth of macroalgae, as shown by Lenzi et al ( , 2015Lenzi et al ( , 2017 and Martelloni et al (2016). As suggested by the results of the present work and of Lenzi et al (2017), if these practices are not adequately commisurate to the dynamics of growth, they may be beneficial for the mats, through the enhancement of their survival under unfavorable environmental conditions and of their subsequent growth.…”

“…Moreover, the fragmentation of thalli caused by the boat transit on a dense mat may enhance the decay or the growth of the mat itself, probably depending on the frequency of disturbance that has been imposed. Lenzi et al (2015) and Martelloni et al (2016) observed the decay of C. linum mats following fragmentation, when the disturbance frequency was 31.58% (12 interventions over a period of 38 days) and 22.22% (60 interventions on a period of 270 days), respectively. In the present study the disturbance frequency was only 16.49% on average, achieving the minimum during the period of LOM increase; such low disturbance frequency may have favored, through the fragmentation of the thalli, the subsequent growth, as suggested by Peckol and Rivers (1995) for Cladophora vagabunda.…”

“…A feasible solution to mitigate the consequences of eutrophication is focusing efforts on a downstream management. Whatever the choices made in this regard, like macroalgal harvesting (Lenzi, 1992;Runca et al, 1996;Guyoneaud et al, 1998) or their fragmentation in situ and the artificial oxidation of sediments (Lenzi et al, 2015(Lenzi et al, , 2017Martelloni et al, 2016), it is important to achieve a detailed knowledge of the conditions occurring in high density mats and their specific characteristics. Particularly, it is necessary to study the growth and physiology of the dominant macroalgae in relation to the trend of the main environmental factors.…”

Artificial Top Layer Sediment Resuspension To Counteract Chaetomorpha Linum (Muller) Kutz Blooms In A Eutrophic Lagoon. Three Years Full-Scale Experience

“…This reduction of the mat might have been affected by the fragmentation of the algae by the propellers of the boats [56], but this action was likely proportionally present in both periods, as the algal mat continued to decrease in its biomass and standing crop until it reached its lowest value, estimated in February 2016, when the action of the boats was sensibly reduced (Table 1; Figure 2). …”