Effect of shading imposed by the algae Chaeotomorpha linum loads on structure, morphology and physiology of the seagrass Cymodocea nodosa.

In shallow coastal waters, seagrass and macroalgae occur together but under eutrophic conditions, bloom-forming algae can take over seagrasses causing an irreversible regime shift. Understanding the effect of macroalgae loads on seagrass meadows at an early stage can help prevent the loss of these ecosystems and the services they provide. In the present study, in situ experiments were conducted for 90 days in Bekalta (eastern coast of Tunisia) to assess the response of the seagrass Cymodocea nodosa when challenged with shading induced by filamentous macroalgae Chaetomorpha linum.

A comparative study of trace elements in Cymodocea nodosa from three semi-enclosed coastal areas in Tunisia.

The present study quantifies the levels of five trace elements (TEs) Zn, Cu, Ni, Pb, and Cd in the leaves and rhizomes of Cymodocea nodosa as well as the surficial sediments from three semi-enclosed coastal areas in Tunisia, in the south Mediterranean Sea. Samples were taken from the Bizerte and Ghar El Melh lagoons and from marina Cap Monastir. The TE ranking was found to be Zn > Cu > Pb > Ni > Cd in sediments and Zn > Cu = Ni = Pb = Cd in C.

Variation along the year of trace metal levels in the compartments of the seagrass Posidonia oceanica in Port El Kantaoui, Tunisia.

The accumulation of the five trace metals (TMs) cadmium, copper, lead, nickel and zinc was measured in Posidonia oceanica leaves. Shoots were seasonally sampled at 8-10-m depth from four stations located in Port El Kantaoui area, Tunisia, during four campaigns performed in 2012. Levels of the five TMs were analyzed using inductively coupled plasma atomic emission spectrometry (ICP-AES) in three compartments of P.

Abundance and diversity of amphipods (Crustacea: Peracarida) on shallow algae and seagrass in lagoonal ecosystem of the Mediterranean Tunisian coast.

Background: Bizerte lagoon is a semi-enclosed marine ecosystem, where various types of human activities have been developed. To investigate the distribution and temporal variation of amphipod assemblage, monthly sampling was conducted at the Menzel Jemil site from October 2009 to September 2010.

Results: Atotal number of 3,620 specimens were collected from floating algae and seagrass allowing the identification of 10 amphipod species.