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This work shows the technical and economical aspects of seaweed farming for the production of phycocolloids or marine gums. Two different cultivation systems were used in four different sites inhabited by Wayúu fisherman communities in the townships of Cabo de La Vela and Carrizal, Guajira Peninsula, Colombia. The productivity and the growth rate of three commercial important macroalgae species, as well as the production costs, investment and returns of 0,5 ha marine farms, taking into consideration the design and construction of cultivation units made with cheap and available materials. The implementation of these farming systems could lead for the technological transfer of the locals. The income obtained through seaweed farming could benefit a large part of the coastal community as an additional and complementary cash crop to their traditional activities, including artisan fishing and goat rising, where the majority thrives in conditions of extreme poverty with the highest unmet basic needs index of the country. 

Marine algal ecology today faces many of the same problems as ecology in general, e.g. lack of generality of experimental results, the difficulty of making long-term predictions, and an apparent lack of agreement as to what constitutes the proper or 'acceptable' way of doing this particular component of science. These problems, if real, affect marine algal ecology everywhere but, in different geographical areas, specific problems also occur; science in parts of Asia has some problems different from those in other parts of the world. Since its inception, research in marine algal ecology has been motivated by many factors, ranging from traditional needs, to curiosity, to survival, to new technology, and economic needs. Each of these has shaped the questions that have been asked by, and the level ofsupportsociety has been willing to supply to, ecology. For example the requisites oftradition pushed marine ecology to ask questions about food and ceremonial biota, and our fears today about loss of biota are pushing for answers to questions about the means of preserving biodiversity. The limitations of many marine ecological studies have been pointed out by different individuals. Their comments have been valuable in forcing us to examine what we are doing as marine ecologists, and how we are doing it. Ecology, and marine algal ecology with it, has been accused of carrying out small-scale studies that have no greater generality than the sites at which the studies were done, and of using statistical procedures that are wrong or inappropriate; also, there is disagreement within the ecological community of how to correct for these 'faults'. Some of the problems arise due to the nature of our particular science, e.g. working with organisms with differing genetic makeup and sensitivity of experimental results to small changes in initial conditions. Other problems are more likely due to the individuals doing the science, e.g. an inability to be an 'expert' on all areas of knowledge required for a modem ecologist (taxonomy, experimental design, data analysis, etc.), and perhaps an unwillingness to recognize that in some instances different methods of data analysis are applicable and valid. As ecologists, we must come to grip with these problems, both for the sake of our science, and for our own sake as practicing ecologists.

The low volume batches of highly-concentrated wastewater discharged from land-based marine recirculating aquaculture systems are ideally suited for treatment by halophyte planted constructed wetlands. To evaluate the role of plants and the effect of planting density on yield and performance in small-scale saline constructed wetlands (CWs), NH4 + + NO3 − + NO2 − = total dissolved inorganic nitrogen (TDIN) and dissolved inorganic phosphorus (DIP) were measured at regular intervals over 24 h periods. CWs were planted with the halophyte Salicornia europaea at high- and low-densities and were compared to the performance of unplanted controls. S. europaea plants were cropped regularly to assess potential commercial yield at the two densities. There was no significant effect of planting density on performance or crop yields and planted beds consistently outperformed the control beds removing 62.0 ± 34.6 mmol N m−2 d−1 (34–73% of influent TDIN) compared to 23.0 ± 26.8 mmol N m−2 d−1 (−1% to 41% of influent TDIN) by control beds. Results for DIP were less clear, significant removal occurred only once, with reduction of 18.3 ± 5.0 mmol P m−2 d−1 by planted beds and 18.1 ± 2.6 mmol P m−2 d−1 by the unplanted controls. The results demonstrate the effectiveness of halophyte-planted CW in treatment of marine aquaculture wastewater

The red alga Gracilaria vermiculophylla, a species native to the waters of Korea and Japan, has invaded marine coastal areas of Europe and the Americas, thriving in conditions that differ from those of its native habitat. In recent years, G. vermiculophylla has been discovered in the Long Island Sound (LIS) estuary growing alongside the native congener Gracilaria tikvahiae. The goal of this study was to determine whether the two strains of G. vermiculophylla from different regions of the world have evolved genetic differences (i.e., ecotypic differentiation) or if the physiological performance of the strains simply reflects phenotypic plasticity. Two strains of G. vermiculophylla (isolated in Korea and LIS) and a strain of the LIS native G. tikvahiae were grown for four weeks under temperatures ranging from 20 to 34°C using a temperature gradient table (all other environmental conditions were kept constant). At the end of each week, wet weight of each sample was recorded, and thalli were reduced to the original stocking density of 1 g L-1 (excess biomass was preserved for tissue carbon and nitrogen analysis). Generally, the growth rates of Korean G. vermiculophylla > LIS G. vermiculophylla > G. tikvahiae. After one week of growth G. tikvahiae grew 9.1, 12.0, 9.4, and 0.2% d-1, at temperatures of 20, 24, 29, and 34°C, respectively, while G. vermiculophylla (LIS) grew 6.6, 6.2, 5.7, and 3.6% d-1. G. vermiculophylla (Korea) grew 15.4, 22.9, 23.2, and 10.1% d-1, much higher than the two strains currently inhabiting the LIS. On average, the LIS G. vermiculophylla strain contained 4-5% DW N, while the Korean strain and G. tikvahiae had more modest levels of 2-3% N DW. However, tissue N content declined as temperature increased in LIS and Korean G. vermiculophylla. The non-native haplotype may have evolved genetic differences resulting in lower growth capacity while concentrating significantly more nitrogen, giving the non-native a competitive advantage.