Relationship of Trace Elements Concentration and Growth Rate in Alsidium triquetrum (Rhodophyta)

Minerals and trace elements content and concentration in marine algae vary depending on species morphology and physiology;as well as growing environmental conditions. Despite this variability, accumulation of magnesium, and especially iron, seems to be common in Chlorophyta;while Rhodophyta and Heterokontophyta show higher affinity to manganese. The red agarophyte Alsidium triquetrum was used to analyze the relationship between metal concentration, environmental conditions and growth rate. Specimens grown in situ showed a large variability of Fe, Mn, Mg, and Al, in thallus tissue concentrations. Further, a compelling relationship between the growth rate and the thallus concentration of Mg and Mn, Zn, and Al was detecte. Manganese, unlike the other trace elements analyzed showed a positive linear relationship between growth rate and tissue content during the period of greatest vegetative growth.

Influence of the Macronutrients N, P and K on the Agarophyte <i>Alsidium triquetrum</i>(S. G. Gmelin) Trevisan, during Experimental Culture

The knowledge of the nutritional requirements and their relation to the physiology of marine algae growth is key to incorporate new species into aquaculture, whose dynamics tend to be largely unknown. The use of Alsidium triquetrum in the pharmacological industry depends on its availability in the natural environment, occasionally scarce. As macroalgae cultivation gains momentum worldwide, it is important to know how the effects of nutrients are modulated in the thallus during cultivation. The linking of the relative growth rates (RGR) of A. triquetrum and their relation with the macronutrients N (nitrogen), P (phosphorus) and K (potassium) at the tissue level under culture conditions constitutes the main contribution of this article. P levels tend to decrease as the plant completes its development. Both the concentration of N and P are higher in the stipe for the month of July, N (25.31 ± 0.26) vs P (0.846 ± 0.02) period when the highest vegetative development is reached. The N and P modulate the patterns of the species’ development over the annual cycle, unlike K, which is not considered a limiting factor. When the temperature and lighting are not favorable for growth, the plant simply accumulates these compounds. As environmental conditions change, these stored compounds are actively used in their growth. The specimens with an initial weight of 50 g present the best accumulated biomass (RGR) throughout the annual cycle.

Dominant Macroalgae in Bahía de Cochinos, Matanzas, Cuba

Spatial-temporal variations of macroalgae were analyzed in a study conducted in Cueva de Los Peces (CP) and Punta Perdiz (PP), two dive sites located on the eastern coast of Bahía de Cochinos. The most conspicuous species found from 3 to 20 m depths were present in the biotopes of ridges and shallow and deep terraces. Sampling was carried out in September 2014, and March and October 2016 by autonomous diving and direct methods. Qualitative visual censuses and quantitative analyzes were used to estimate the coverage (%) of the genera according to the AGRRA methodology with the use of the 10 m linear transect and quadrats as the sampling unit. The first list of macroalgae for the area is offered that includes 49 taxa of which 10 were Rhodophyta, 10 Ochrophyta (Phaeophyceae), and 29 Chlorophyta. The dominant genera during the study period were Halimeda, Dictyota, Lobophora, and Udotea. Spatial differences were found regarding the specific composition. Temporal variations were evidenced in terms of the relative abundance of the genera present, which reveals temporal changes in the qualitative structure, where some species replace others. The information obtained is pioneering and can serve as a comparative baseline for future monitoring of the area.

Population Dynamics of Colonizing Fauna and Its Effect on Growth Rates of the Farmed Red Alga Alsidium triquetrum (S. G. Gmelin) Trevisan

Herbivores can drastically alter the morphology of macroalgae by directly consuming tissue and by inflicting structural wounds. Macroalgae host abundant and diverse epibiont communities, the dynamics of which tend to be mostly unknown in space and time. As the cultivation of macroalgae gains momentum worldwide, it is key to measure how epibionts could affect algal performance. We examined the epibiont community associated with farmed Alsidium triquetrum, a red macroalga with growing pharmacological interest. Measurements were conducted over two independent 60-day periods, one in summer and one in winter. Epibionts showed different patterns of succession in both seasons. Crustaceans, mainly amphipods, showed the highest overall density, with deleterious effects on daily growth rates of A. triquetrum in winter. Adverse effects as a function of epibionts were not detected in summer. A. triquetrum is a perennial alga. However, its performance as a crop in the nearshore can be significantly affected by the epibiont community structure that persists in winter. Amphipods and ascoglossan molluscs were risk factors in the mariculture of this agarophyte. In winter, they can destroy plants when they reach more than five individuals per gram of fresh biomass. Results highlight that commercial farming of A. triquetrum would be successful if grown throughout the summer.

New Records of Marine Macroalgae on the Caribbean on Coast of Costa Rica

The results obtained in this study highlight that further the macroalgae diversity in this region is even higher than what is reported to date. Here we present eight new records of marine macroalgae collected from the Caribbean coast of Costa Rica between March 2011 and May 2019. The morphological characteristics of Bryocladia cuspidata, Ceratodictyon variabile, Gracilaria hayi, Padina boergesenii, Zonaria tournefortii, Sargassum furcatum, Chaetomorpha aerea, and Bryopsis pennata var. secunda are described. The genera Bryocladia and Zonaria are reported for the first time for this region.

Two New Species of the Genus Dictyota (Phaeophyceae: Dictyotales) from the Mexican Caribbean

During a molecular characterization of the genus Dictyota J. V. Lamouroux (Phaeophyceae, Dictyotales) along the Mexican coasts of the Gulf of Mexico and the Mexican Caribbean, using psbA and cox1 genes, it was found that two particular collections did not match with the sequences published for a total of 39 species of Dictyota. For each gene, both collections diverged in high-uncorrected “p” distance values with respect to other related species. This high genetic divergence was corroborated by morphological analysis. Hence, we proposed Dictyota mayae J. Lozano-Orozco & Sentíes and Dictyota pedrochei J. Lozano-Orozco & Sentíes as new species.

<i>Kappaphycus alvarezii</i>(Rhodophyta): New Record of an Exotic Species for the Caribbean Coast of Costa Rica

Kappaphycus alvarezii, a red macroalgal species native to South-East Asia, has been introduced for commercial purposes to more than 20 tropical countries. In 2000, Panama became the first Central American country to develop its cultivation following a pilot-commercial approach. Twelve years after his introduction to Panama, the species was found to the south Caribbean coast. In the present study, we report the first record of K. alvarezii collected in Costa Rican waters. Genetic identification of the sample was performed with the mitochondrial marker cox2-cox3 intergenic spacer, and phylogenetic analyses showed that the sample collected grouped into a monophyletic clade with GenBank sequences from Vietnam, Indonesia, the Philippines, Brazil and Venezuela. Here we provide further description of its position with respect to other strains of K. alvarezii collected globally. Its possible route of entry to the Caribbean coast of Costa Rica is discussed. To date, it is possible to locate K. alvarezii in different areas away from the production fields which show its dispersion, and that the species is expanding;but more studies are needed to know the phase of colonization in which it is located because it is a combination of natural factors and human exploitation that determines the invasive potential of the species.

Codon Usage of Chloroplast Gene rbcL in Laurencia sensu lato(Rhodophyta)species

Recent advances in molecular biology make it possible to sequence not only genes or genomes,but also to understand codon dynamics.For the organelle genes of these organisms,a small set of preferred codons are used for encoding proteins.For the first time,this paper treats the divergence of synonymous codon usage and its bias in the rbcL gene within the Laurencia complex of red algae.We observed that the synonymous codon preference biases in rbcL are large and differ among species.A clear distinction in codon usage between genera is evident:the genera Dasya and Delesseria use a set that fluctuated between 53 and 58 codons.Whereas,in the genera Ceramium,Chondrophycus,Chlamydomonas,Chlorella,Laurencia s.s,Osmundea,and Palisada codon usage indicates a higher restriction fluctuating between 40 to 51 codons.Laurencia complex genera and other representative algae showed a defined composition pattern,with lower percentage values of NNC/G(7-24.9%).Dasya and Delesseria showed a selective pattern tendency because of high percentage values of NNC/G(54-55%).The estimated codon bias parameters were tested to infer systematic relationships and match suitable codons with the NNC/G codon percentages.Cluster analysis based on Codon Usage supports phylogenetic relationships between Chondrophycus,Palisada,Laurencia,Osmundea,and Yuzurua species.

Isolation and Characterization of 26 Microsatellite Loci for the Shortfin Silverside Fish <i>Chirostoma humboldtianum</i>Valenciennes1835 (Atherinopsidae: Menidiinae) Derived from Next Generation Sequencing and Their Cross-Amplification in Central Mexican Atherinopsids

The endemic silverside fish C. humboldtianum is of great ichtyologycal, economical and cultural relevance in central Mexico and it has been suggested that it is among a group of other “peces blancos”, the most ancestral species. Here we characterized a set of 26 microsatellite loci from the species in order to further assess population and phylogeographic issues that aid in evaluating their highly impacted populations. From 58 primer pairs tested on specimens from Villa Victoria dam (Rio Balsas Basin), 26 loci positively amplified on the species and cross-primed on specimens of the closely related and threatened Poblana alchichica, C. promelas and C. riojai. Loci resolved medium and high genetic variation (mean NA = 14.3, SD = 9.38;mean HO & HE = 0.47, SD = 0.32 and 0.58, SD = 0.32, respectively) and it is expected that these polymorphic loci are also useful in studing threatened atherinopsid species.