Direct and indirect effects of Gracilaria vermiculophylla on native Fucus vesiculosus

The perennial red macroalga Gracilaria vermiculophylla (Ohmi) Papenfuss has recently been introduced to the Baltic Sea and is a potential competitor to Fucus vesiculosus, the most common native perennial alga in large parts of the Baltic Sea. Gracilaria might interfere with Fucus through direct competition for resources. In addition, Gracilaria is a favoured refuge for mesograzers, which prefer to feed on Fucus. Mesocosm-experiments were conducted over one year in the Kiel Fjord in order to test the direct and indirect effects of Gracilaria on Fucus. Fucus was incubated with Gracilaria at three different densities and grazers in high or low abundances. High densities of Gracilaria inhibited the growth of Fucus adults and also reduced the half-life-time of Fucus germlings. Associated grazers also had a negative effect on Fucus adults. Our results suggest that Gracilaria is able to influence Fucus in the Baltic Sea through direct competition for resources and by exposing it to higher grazer pressur

Tracking environmental trends in the Great Bay Estuarine System through comparisons of historical and present-day green and red algal community structure and nutrient content

Monitoring macroalgae populations is an effective means of detecting long term water quality changes in estuarine systems. To investigate the environmental status of New Hampshire’s Great Bay National Estuarine Research Reserve, this study assessed the abundance/distribution of macrophytes, particularly Gracilaria and Ulva species, relative to eutrophication patterns; compared historical (1970s-1990s) and current algal biomass/cover at several sites; and compared Ulva and Gracilaria tissue N/P content to ambient and historical levels. Ulva and Gracilaria biomass/cover have increased significantly at several sites. Cover by Ulva species, at seasonal maxima, was over 90 times the value recorded in the 1970s at Lubberland Creek, and exceeded 50% at all sites in the upper estuary. Gracilaria cover was greater than 25% at Depot Road in the upper estuary, whereas the historical measure was 1%. Sequencing of ITS2, rbcL and CO1 revealed the presence of previously undetected Ulva and Gracilaria species, including Gracilaria vermiculophylla (Ohmi) Papenfuss, an invasive species of Asian origin. Gracilaria vermiculophylla has exceeded G. tikvahiae as the dominant Gracilaria species in Great Bay. Historical voucher specimen screening suggests G. vermiculophylla was introduced as recently as 2003. Nitrogen and phosphorus levels are elevated in the estuary. We should expect continued seasonal nuisance algal blooms

Eelgrass Distribution in the Great Bay Estuary and Piscataqua River for 2017

Eelgrass distribution in Great Bay, Little Bay, and the Piscataqua River Estuary was mapped from aerial photography acquired on August 24, 2017. The total area of eelgrass beds with 10% or greater cover and a polygon area equal to or greater than 100 square meters was 625.9 hectares or 1546.7 acres. Eelgrass polygons were coded for Assessment Zone location and the results reported for each zone. The largest concentration of eelgrass was found in Great Bay with lesser amounts in the vicinity of Portsmouth Harbor. The total area of eelgrass beds with 10% or greater cover and a polygon area equal to or greater than 100 square meters has decreased by 142 acres which is approximately an 8.5% decrease from the previous year

Results of 2013 Macroalgal Monitoring and Recommendations for Future Monitoring in Great Bay Estuary, New Hampshire

The recently designated nitrogen impairment and reports of elevated macroalgal growth in Great Bay Estuary indicate ecological imbalance. However, reversing the Estuary’s ecological decline will require commitment of considerable resources and is complicated by the variety of sources that deliver nitrogen to the Estuary and the intermittent nature of historic macroalgal monitoring. To advance our understanding of the macroalgal and nitrogen dynamics of the Estuary, data were collected via three approaches: 1) assessing plant cover and biomass along transects; 2) assessing plant cover at randomly selected points; and 3) comparing the nitrogen isotope ratios of macroalgae collected from different habitats. The results offer insight into changes in macroalgal abundance and species composition and the relative importance of various nitrogen sources to macroalgae in Great Bay. Overall, our results corroborate the findings of increasing macroalgal blooms in previous studies and suggests plausible directions for a long-term macroalgal monitoring program

Ethnobotany Study of Seaweed Diversity and Its Utilization in Warambadi, Panguhalodo Areas of East Sumba District

This paper reports the ethnobotany study of seaweed diversity in Warambadi –Panguhalodo areas of East Sumba District, the island of Sumba. The study recorded19 genera of 54 species of seaweed, which were utilized as food or edible seaweed.The group consisted of 17 species of green algae, 17 species of red algae, and 20species of brown algae. The study also reported that 18 genera of 38 species weretraditionally utilized for medicinal purposes as herbal medicine. The herbal speciesconsisted of 7 species of green algae, 13 species of red algae, and 18 species ofbrown algae.Seaweed is traditionally consumed as food in various forms: raw as salad and vegetable,as pickle with sauce of allspice or with vinegar, as relish or sweetened jellies and alsocooked for vegetable soup. As herbal medicine seaweed is usually used for traditionalcosmetics, as antipyretic and antiseptic, as vermifuges, and treatments for cough andasthma, hemorrhoid, nosebleed and boils, goiter and scrofula, stomach ailments andurinary diseases.Indigenous knowledge on seaweed still exist and are continually employed bypeople living in particular areas such as the Sumba and Sabu ethnic groups. Yet,the knowledge is gradually decreasing due to localities, socio-economic change andcultural development

Eficiencia de absorción de nutrientes de Gracilaria chilensis y Ulva lactuca en un sistema multitrófico integrado con el abalón rojo Haliotis rufescens

Indexación: Web of Science; Scielo.ABSTRACT. The current study examined the nutrient uptake efficiency of Ulva lactuca and Gracilaria chilensis cultivated in tanks associated with the wastewater of a land-based abalone culture. The experiments evaluated different seaweed stocking densities (1200, 1900, 2600, and 3200 g m-2) and water exchange rates (60, 80, 125, and 250 L h-1). The results show that both U. lactuca and G. chilensis were efficient in capturing and removing all of the inorganic nutrients originating from the abalone cultivation for all of the tested conditions. Furthermore, an annual experiment was performed with U. lactuca, cultivated at a stocking density of 1900 g m-2 and at a water exchanged rate of 125 L h-1, in order to evaluate seasonal changes in the nutrient uptake efficiency, productivity, and growth rate associated with the wastewater of a land-based abalone culture. The results confirmed high uptake efficiency during the entire year, equivalent to a 100% removal of the NH4, NO3, and PO4 produced by the land-based abalone culture. The growth rate and productivity of U. lactuca presented a marked seasonality, increasing from fall until summer and varying from 0.5 ± 0.2% to 2.6 ± 0.2% d-1 and 10 ± 6.1% to 73.6 ± 8.4% g m-2 d-1 for sustainable growth rate and productivity, respectively. We conclude that there is sufficient evidence that demonstrates the high possibility of changing the traditional monoculture system of abalone in Chile, to a sustainable integrated multi-trophic aquaculture system, generating positive environmental externalities, including the use of U. lactuca as a biofiltration unit.Resumen: Se analizó la eficiencia de captación de nutrientes de Ulva lactuca y Gracilaria chilensis, cultivadas en estanques asociados a aguas de desecho proveniente de un cultivo del abalón rojo Haliotis rufescens. Los experimentos consideraron evaluar diferentes densidades de cultivo de algas (1200, 1900, 2600 and 3200 g m-2) y tasas de recambio de agua (60, 80, 125 y 250 L h-1). Los resultados mostraron que tanto U. lactuca como G. chilensis fueron eficientes en la captación de nutrientes inorgánicos provenientes del cultivo de abalón, en todas las condiciones probadas, con remoción total de los nutrientes aportados por el cultivo. De la misma forma se realizó un experimento anual con U. lactuca, siendo cultivada con densidad de 1900 g m-2 y tasa de recambio de agua de 125 L h-1 para evaluar cambios estacionales en la eficiencia de captación de nutrientes, así como en la productividad y tasa de crecimiento de U. lactuca. Los resultados confirmaron una alta eficiencia de captación de U. lactuca durante todo el año, equivalente a la remoción del 100% del NH4, NO3 y PO4 aportado por el cultivo de abalón. La tasa de crecimiento y la productividad de U. lactuca presentó una marcada estacionalidad, incrementando de otoño al verano, variando de 0,5 ± 0,2 a 2,6 ± 0,2% d-1 y 10 ± 6,1 a 73,6 ± 8,4 g m-2 d-1, respectivamente. Se concluye que existen antecedentes suficientes que demuestran que es altamente posible cambiar la actividad tradicional de cultivo de abalón por un sistema integrado multitrófico, alcanzando externalidades ambientales positivas que incluyen U. lactuca como unidad de biofiltración.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X201400030001

Dietary supplementation of heat-treated Gracilaria and Ulva seaweeds enhanced acute hypoxia tolerance in gilthead sea bream (Sparus aurata)

Intensive aquaculture practices involve rearing fish at high densities. In these conditions, fish may be exposed to suboptimal dissolved O2 levels with an increased formation of reactive O2 species (ROS) in tissues. Seaweeds (SW) contain biologically active substances with efficient antioxidant capacities. This study evaluated the effects of dietary supplementation of heat-treated SW (5% Gracilaria vermiculophylla or 5% Ulva lactuca) on stress bioindicators in sea bream subjected to a hypoxic challenge. 168 fish (104.5 g average weight) were distributed in 24 tanks, in which eight tanks were fed one of three experimental diets for 34 days: (i) a control diet without SW supplementation, (ii) a control diet supplemented with Ulva, or (iii) a control diet with Gracilaria. Thereafter, fish from 12 tanks (n=4 tanks/dietary treatment) were subjected to 24 h hypoxia (1.3 mg O2 l-1) and subsequent recovery normoxia (8.6 mg O2 l-1). Hypoxic fish showed an increase in hematocrit values regardless of dietary treatment. Dietary modulation of the O2-carrying capacity was conspicuous during recovery, as fish fed SW supplemented diets displayed significantly higher haemoglobin concentration than fish fed the control diet. After the challenge, survival rates in both groups of fish fed SW were higher, which was consistent with a decrease in hepatic lipid peroxidation in these groups. Furthermore, the hepatic antioxidant enzyme activities were modulated differently by changes in environmental O2 condition, particularly in sea bream fed the Gracilaria diet. After being subjected to hypoxia, the gene expression of antioxidant enzymes and molecular chaperones in liver and heart were down regulated in sea bream fed SW diets. This study suggests that the antioxidant properties of heat-treated SW may have a protective role against oxidative stress. The nature of these compounds and possible mechanisms implied are currently being investigated.Fil: Magnoni, Leonardo Julián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina. Universidad de Porto; PortugalFil: Martos Sitcha, Juan Antonio. Consejo Superior de Investigaciones Científicas; EspañaFil: Queiroz, Augusto. Universidad de Porto; PortugalFil: Calduch Giner, Josep Alvar. Consejo Superior de Investigaciones Científicas; EspañaFil: Magalhaes Gonçalves, Jose Fernando. Universidad de Porto; PortugalFil: Rocha, Cristina M.R.. Universidad de Porto; PortugalFil: Abreu, Helena T.. ALGAplus; PortugalFil: Schrama, Johan W.. Wageningen University; Países BajosFil: Ozorio, Rodrigo O.A.. Universidad de Porto; PortugalFil: Perez Sanchez, Jaume. Consejo Superior de Investigaciones Científicas; Españ

Utilization of seaweeds in Thailand

Different seaweeds harvested from natural stocks are utilized in Thailand as human food and animal feed and for medicinal purpose and extraction of crude agar. Gracilaria and Porphyra are the most exploited commercially. Commercial cultivation through seaweed farming is recommended

CAROTENOIDS CONTENT OF COMMERCIAL SEAWEED IN BALI

In Bali there are several types of seaweed that has long been used as a source of food by people. These seaweed local name are Bulung Boni (Caulerpa spp.) and Bulung Sangu (Gracilaria spp.). However the study of total carotenoids content and types of carotenoids of these seaweed are very limited, therefore need to be further sudy. The types of carotenoids in this study identified based on the retention of value (Rf) on thin layer chromatography. This research concluded that total carotenoids of Bulung Boni (Caulerpa spp.) higher than Bulung Sangu (Gracilaria spp.). Total carotenoids were 57.734 mg / 100 g in Bulung Boni, and 1.776 mg /100 g in Bulung Sangu. The separation of carotenoids Bulung Boni and Bulung Sangu on thin layer chromatography obtained several types of carotenoids. Based on the calculation Rf values on Bulung Boni found as many as nine types of carotenoids such as neoxanthin, astaxanthin free, antheraxanthin ,canthaxanthin ,astaxanthin monoester, fucoxanthin, chlorophyll b, astaxanthin diester, and beta carotene In Bulung Sangu found eight types of carotenoids, such as neoxanthin, violaxanthin, astaxanthin free, antheraxanthin, lutein, chlorophyll b, chlorophyll a, and beta caroten