Spatio‐temporal dynamics and biomass of Cymodocea nodosa in Bekalta (Tunisia, Southern Mediterranean Sea)

Abstract

Leaf growth, biomass and production of Cymodocea nodosa were measured from October 2006 to September 2007 in Monastir Bay (Tunisia). Shoot density showed a clear seasonal pattern, increasing during spring and summer and decreasing during fall and winter. Monthly mean shoot density ranged between 633 ± 48 and 704 ± 48 shoots∙m−2. The monthly average total biomass ranged between 560 ± 37 and 646 ± 32 g dry weight (DW)∙m−2. Total biomass varied significantly among stations and sampling times but did not show seasonal variation. Leaf plastochrone intervals varied seasonally, with an annual average of 28–30 days. Leaf productivity was highest in August (2.61 g DW∙m−2∙day−1) and lowest in February (0.35 g DW∙m−2∙day−1). Annual belowground primary production varied from 263 to 311 g DW∙m−2∙year−1. Annual leaf production was approximately equal for all the stations (from 264 to 289 g DW∙m−2∙year−1). Variability in water temperature, air temperature and salinity explained the annual variability in biological characteristics. Changes in belowground and total biomass were not correlated with seasonal variability in the environmental parameters monitored. Additionally, a literature review was conducted of C. nodosa features at other Mediterranean sites, encompassing 30 studies from 1985 to 2014.

The biomass–density relationship in seagrasses and its use as an ecological indicator

“…obs. Location Latitude Cymodocea nodosa Agostini et al [ 72 ] 12 Urbinu lagoon, Corsica 42.02 Cymodocea nodosa Duarte and Sand-Jensen [ 71 ] 47 Ebro Delta, Spain 40.72 Cymodocea nodosa Sghaier et al [ 75 ] 36 Monastir Bay, Tunisia 35.37 Cymodocea nodosa Peduzzi and Vukovic [ 74 ] 17 Golf of Trieste, Italy 45.7 Cymodocea nodosa Cunha e Duarte [ 73 ] 5 Ria Formosa, Portugal 37.10 Halodule wrightii Hall et al [ 60 ] 12 Florida Bay, USA 25.14 Halodule wrightii Creed (this study) 992 Multiple sites, American continent – Posidonia oceanica Terrados and Pons [ 76 ] 5 Magaluf, Mallorca Island, Spain 39.30 Posidonia oceanica Terrados and Pons [ 76 ] 5 Ses Salines, Mallorca Island, Spain 39.15 Posidonia sinuosa Keulen [ 77 ...…”

Reconstruction of Cymodocea nodosa’s dynamics as a tool to examine the conservation status of a Mediterranean declared marine protected area

“…Freshwater runoff conducted from watersheds during the rainy months may also enhance nutrient enrichment. Concerning clonal growth regulation, previous studies underlined that it exhibits intraspecific variability in response to meadow genetic diversity (Manez-Crespo et al, 2020) and local scale environmental conditions (hydrodynamics, sediment dynamics, light, salinity, temperature, nutrients, and heavy metals, among others; Cunha & Duarte, 2005;Ambo-Rappe 2011;Sghaier et al, 2017;Tuya et al, 2019;Manez-Crespo et al, 2020). Azizi et al (2020) recorded an average monthly salinity of the park water column oscillating between 36 and 40.…”

“…Azizi et al (2020) recorded an average monthly salinity of the park water column oscillating between 36 and 40. The optimum C. nodosa meadows productivity is at around oceanic salinity (33 -37), while extreme or suboptimal values negatively affect their photosynthesis, metabolism, and growth, determining their biomass, productivity and survival (Vermaat et al, 2000;Pagès et al, 2010;Fernandez-Torquemada & Sánchez-Lizaso, 2011;Sghaier et al, 2017;Tsioli et al, 2019). Illegal fishing activities are another severe issue that can threaten the survival of Al Hoceima meadows.…”