Colonization of novel algal habitats by juveniles of a marine tube-dwelling amphipod

Background Dispersal is an important process affecting population dynamics and connectivity. For marine direct developers, both adults and juveniles may disperse. Although the distribution of juveniles can be initially constrained by their mothers’ choice, they may be able to leave the parental habitat and colonize other habitats. We investigated the effect of habitat quality, patch size and presence of conspecific adults on the colonization of novel habitats by juveniles of the tube-dwelling amphipod Cymadusa filosa associated with the macroalgal host Sargassum filipendula. Methods We tested the factors listed above on the colonization of juveniles by manipulating natural and artificial plants in both the field and laboratory. Results In the laboratory, juveniles selected high-quality habitats (i.e., natural alga), where both food and shelter are provided, when low-quality resources (i.e., artificial alga) were also available. In contrast, habitat quality and algal patch size did not affect the colonization by juveniles in the field. Finally, the presence of conspecific adults did not affect the colonization of juveniles under laboratory condition but had a weak effect in the field experiment. Our results suggest that C. filosa juveniles can select and colonize novel habitats, and that such process can be partially affected by habitat quality, but not by patch size. Also, the presence of conspecifics may affect the colonization by juveniles. Successful colonization by this specific developmental stage under different scenarios indicates that juveniles may act as a dispersal agent in this species.

Physiological performance by growth rate, pigment and protein content of the brown seaweed Sargassum filipendula (Ochrophyta: Fucales) induced by moderate UV radiation exposure in the laboratory

UV radiation is a factor affecting the distribution and physiology of photosynthetic organisms in an aquatic ecosystem. Studies with macroalgae indicate diverse biological disturbances in response to UV radiation. This work aimed to study sensitivity of the brown macroalga Sargassum filipendula exposed to UV radiation: PAR (control), PAR+UVA+UVB(++) and PAR+UVA(++)+UVB. Changes in the physiological parameters growth rate, total soluble proteins, photosynthetic pigments and the UV-vis absorbing compounds were analysed after T0, T4, T7 and T10 (days) of UV exposure. Physiological parameters showed little variation between treatments and over time, suggesting that moderate UV radiation doses could regulate resistance responses to re-establish the cellular homoeostasis condition through activation of an antioxidant defence system, such as an overproduction of phenolic compounds. Responses recorded in S. filipendula would be related to acclimation mechanisms against acute UV radiation stress, triggering resistance responses to avoid serious damage to the metabolic machinery, activating control systems to maintain hormesis, and homoeostasis of deleterious actions of reactive species, similar to the phenomenon known as preparation for oxidative stress. Finally, UV-visible absorption spectra showed absorption bands evidencing the presence of mainly UV-absorbing compounds with photoprotective function, such as phlorotannins, flavonoids and carotenoids, which could provide adaptive advantages for organisms exposed to UV radiation.

Extração de alginato da Sargassum filipendula para remoção de metais tóxicos e preparação de micropartículas de blenda de sericina/alginato comercial para aplicação farmacêutica

O intuito desse projeto foi a preparação e utilização do resíduo da extração de alginato da alga Sargassum filipendula para remoção de metais tóxicos, como o cromo, de sistemas aquosos através da bioadsorção. O projeto também envolveu a preparação de partículas farmacêuticas, formadas pelo método de gelificação, a partir da blenda de sericina e alginato comercial para incorporação de cetoprofeno e reticulada com proantocianidina, a fim de obter uma liberação controlada do fármaco, evitando picos de liberação e, consequentemente, a ocorrência de efeitos colaterais.

PENGARUH KOMPOSISI JENIS PAKAN YANG BERBEDA TERHADAP PERTUMBUHAN TUKIK PENYU SISIK (Eretmochelys imbricata) DI PENETASAN SEMI-ALAMI PENYU TAMAN NASIONAL KARIMUNJAWA (The Effect of Different Feeding Composition on Growth of Baby Hawksbills Turtle (Eretmochelys imbricata) in Semi-Natural Hatching Den in Karimunjawa National Park)

Populasi alamiah penyu di Indonesia terus menurun 20 - 30% per tahun terutama lebih disebabkan oleh faktor manusia dibandingkan dengan faktor alam dan predator. Beberapa di antara teknik penyelamatan untuk pelestarian penyu antara lain melalui penetasan di sarang semi-alami, perlindungan translokasi habitat (konservasi in-situ), penegakan hukum, penyuluhan dan pemberdayaan masyarakat sekitar. Di sarang semi-alami jenis pakan yang tepat pada saat pemeliharaan awal tukik sebelum dilepas ke laut akan mempengaruhi kelulus-hidupan mereka. Padahal, sampai saat ini jenis pakan yang tepat untuk tukik belum banyak diketahui. Penelitian ini menggunakan tiga 3 perlakuan pakan (Sardinella lemuru 100%; Sargassum filipendula 100%; campuran S. lemuru dan S. filipendula 50:50%), analisis data enggunakan Rancangan Acak Lengkap (RAL) dengan 3 pengulangan. Secara statistik, diketahui bahwa tiap perlakuan pakan menghasilkan perbedaan pada variabel panjang, lebar karapas dan bobot tukik. Berdasarkan analisis alometri tukik E.imbricata selama penelitian, dihasilkan konstanta b < b antar perlakuan yang menunjukkan bahwa pertumbuhan bersifat alometri negatif pada variabel panjang karapas dan bobot tubuh serta panjang dan lebar karapas; kecuali pada hubungan panjang dan lebar karapas tukik dengan pakan S. lemuru. The population of sea turtles in Indonesia continued to decrease by 20-30% each year. The decline in natural turtle populations is caused mainly by human factors rather than natural factors and predator. Among others, rescue and preservation of turtles can be accomplished through rearing in a semi-natural den, protection of the habitat translocation (in-situ conservation), law enforcement, education and empowerment of local communities. The proper type of feed for the hatchlings to provide information on required nutrient in optimizing the growth has not been known until now. The methods used in this study was an experimental method apllying Complete Randomised Design with three feeding treatments (100% S. lemuru; 100% Sargassum filipendula; 50:50% mixed of S. lemuru and S. filipendula). The results showed that carapace length, carapace width and body weight differed statistically (P<0.05) in every feed treatment. Hatchlings showed negative allometric (b < ) in carapace length to weight as also carapace length to its width. Isometry in carapace length and width is only shown by hatchlings fed with S. lemuru

Remoção de íons cobre em sistema adsortivo de leito fixo utilizando resíduo da extração do alginato a partir da alga Sargassum filipendula

A bioadsorção tem apresentado destaque como método alternativo direcionado para remoção de metais tóxicos de efleuntes diluídos. Neste estudo foram realizados ensaios de remoção de cobre em colunas de leito fixo em que foi avaliado o efeito da vazão na remoção de cobre pelo resíduo da extração do alginato acidificado. A vazão de 0,5 mL/min foi definida como promissora para estudos posteriores, devido aos seus resultados satisfatórios em relação à altura da Zona de Transferência de Massa (ZTM) e porcentagem de remoção total. Modelos de curva de ruptura, como Bohart-Adams e Thomas, apresentaram ajustes adequados aos valores experimentais.