In order to evaluate suitable remediation strategies for Cu-polluted soils, the growth, tolerance, and Cu accumulation of Sarcocornia perennis and Limonium brasiliense were studied in hydroponic culture using different Cu concentrations, with and without Undaria pinnatifida compost. Most measured variables (e.g., water content, aboveground dry weight, malondialdehyde, pigments concentrations, tolerance index) showed a negative effect of high Cu levels in plants without compost but not in plants with compost. Plants accumulated high Cu levels in belowground tissues (bioaccumulation factor > 1) showing low translocation to aboveground parts. Based on the results, we suggest two remediation strategies: a short-term strategy: root absorption of Cu by halophytes, and a long-term strategy: using halophytes and U. pinnatifida compost, involving absorption of Cu by the plants together with metal immobilization in the substrate. This last strategy offers an additional advantage: it provides a use for seaweed waste, considered a problem for several coastal cities.

Triphenyltin chloride (TPTCL) is a well-known marine pollutant that may constitute major environmental threats to seaweed mariculture. In the present study, the toxic effects of TPTCL on physiology and ultrastructure of cultivated sporophytes of Undaria pinnatifida were investigated under different TPTCL concentrations ranging from 0 to 100 μg L⁻¹. Significant negative effects of increased TPTCL concentration were detected in the relative growth rates, survival percentages and chlorophyll a contents of young and adult sporophytes. Low TPTCL concentrations could significantly stimulate the activities of enzymes related to nitrogen metabolism. The chloroplast, mitochondria and nucleus inside cells were greatly damaged by TPTCL. Meanwhile, significant increases of electron dense deposits and physodes were found. Additionally, young sporophytes exhibited greater tolerance to TPTCL stress than adult sporophytes. The results of this study indicate that coastal TPTCL pollution could reduce the productivity and quality of cultivated U. pinnatifida.

After the first report of Undaria pinnatifida in north Portugal (between 1999 and 2007), a rapid spread of this species could be expected due to the presence of a stable population and the favourable environmental conditions proposed by distribution models. However, field surveys showed that U. pinnatifida was not present in most of the rocky shores in north Portugal. It seems that U. pinnatifida cannot outcompete native species outside of marinas in north Portugal. The only population in natural rocky shores was found in Buarcos, where this species was frequent. This study provides density data of U. pinnatifida that will be useful in the future to monitor changes on its abundance and distribution in the centre and south of Portugal.

Understanding population dynamics of established invasive species is important for designing effective management measures and predicting factors such as invasiveness and ecological impact. The kelp Undaria pinnatifida has spread to most temperate regions of the world, however a basic understanding of population dynamics is lacking for many regions. Here, Undaria was monitored for 2 years, at 9 sites, across 3 habitats to investigate habitat-related variation in population structure, reproductive capacity and morphology. Populations on marina pontoons were distinct from those in reef habitats, with extended recruitment periods and higher abundance, biomass, maturation rates and fecundity; potentially driven by lower inter-specific and higher intra-specific competition within marinas. This suggests that artificial habitats are likely to facilitate the spread, proliferation and reproductive fitness of Undaria across its non-native range. More broadly, generalising population dynamics of invasive species across habitat types is problematic, thus adding high complexity to management options.

Besides being food and a refuge to marine species, macroalgae are a powerful and renewable economic resource. However, they may introduce microplastics (MPs) in the trophic chain. We developed a reliable analytical method to characterize and quantify MPs in common and edible macroalgae. Several digestion methods and filters, along with various measurement options, were studied. A new enzymatic-oxidative protocol with a unique final filtration was selected and validated with a mixture of 5 commercial macroalgae (Undaria pinnatifida spp, Porphyra spp, Ulva spp, Laminaria ochroleuca and Himanthalia elongate). Further, it was shown that washing the macroalgae to release MPs is suboptimal and the potential adhesion of MPs to macroalgae was evaluated. A filter subsampling strategy that scans 33.64 % of its surface reduced the time required to characterize <70 μm particles and fibres directly on the 47 mm diameter filter using an IR microscope (1 sample/day).

Angiogenesis, formation of new blood vessels from preexisting one, is a critical step of tumorgenesis of solid tumors. Therefore, antiangiogenic therapy is one of the promising approaches to control tumor growth. In the past 20 years, a lot of compounds have been tested for their antiangiogenic properties. Bevacizumab, Avastin®, the first antiangiogenic drug approved by the US FDA, has been widely used in clinic for treating cancer. Indeed, many synthetic compounds are highly toxic and exert side effects even though they are effective in inhibiting neovessel formation and cancer cell growth. Using natural compounds or their derivatives is one of the ways to solve these problems. Sinomenine and ginsenosides are common antiangiogenic and anticancer compounds that are extracted from herbal medicines. Recent findings suggested that marine algae-derived natural pigments also possess similar activities. It has been reported that fucoxanthin from Undaria pinnatifida, Siphonaxanthin from Codium fragile, can inhibit angiogenesis and cancer growth effectively. In conclusion, natural compounds derived from marine algae could provide a novel and safe source for new drug development in anticancer and antiangiogenic properties in the future.