Effects of Sediment Fertilization and Burial on Cymodocea nodosa Transplants; Implications for Seagrass Restoration Under a Changing Climate

Sediment fertilization is recommended for improving seagrass restoration efforts, but few studies have evaluated the efficacy of such practice. Increasing storm frequency due to global change could lead to greater sediment mobilization. Understanding how this alteration will interact with fertilization to affect transplants is essential for future restoration planning. We examined the individual and combined effects of nutrients (ambient vs. repeated addition) and burial (control vs. increased frequency and intensity) on the performance and biomass partitioning of transplants of the seagrass Cymodocea nodosa at two sites within a north‐western Mediterranean meadow. Fertilization stimulated the production of shoots, total biomass, and branching. Burial increased leaf sheath length in one site while reduced shoot number, leaf number, leaf sheath length, total biomass, net shoot gain, and root‐to‐shoot ratio in the other site. Regardless of the site, fertilization and burial interaction reduced the length of vertical internodes and horizontal rhizomes, and the net shoot gain. Our research demonstrates that sediment fertilization ensures rapid colonization of restoration sites, providing C. nodosa plants up to eight times larger than controls in one growing season. However, it also indicates that interaction of increased burial and nutrients reduced the gain in terms of vegetative expansion and depressed vertical growth, making plants more vulnerable to subsequent disturbances. Therefore, seagrass restoration practitioners should account for changes in sediment elevation at transplanting sites when planning restoration programs and carefully evaluate the opportunity of applying fertilizers in sites subjected to greater sediment accumulation to avoid failure.     

Population parameters and conservation implications for one of the world's rarest marine fishes,the red handfish (Thymichthys politus)

Population estimates are required for effective conservation of many rare marine species, but can be difficult to obtain. The critically endangered red handfish (Thymichthys politus) is a coastal anglerfish known only from two fragmented populations in southeast Tasmania, Australia. It is at a high risk of extinction due to low numbers, loss of habitat, and the impacts of climate change. To aid conservation efforts, we provide the first empirical population size estimates of red handfish and investigate other important aspects of the species' life history, such as growth, habitat association, and movement. We surveyed both red handfish local populations via underwater visual census on scuba over 3 years and used photographic mark-recapture techniques to estimate biological parameters. In 2020, the local adult population size was estimated to be 94 (95% confidence interval [CI] 40–231) adults at one site, and 7 (95% CI 5–10) at the other site, suggesting an estimated global population of 101 adults. Movement of individuals was extremely limited at 48.5 m (± 77.7 S.D. ) per year. We also found evidence of declining fish density, a declining proportion of juveniles, and increasing average fish size during the study. These results provide a serious warning that red handfish are likely sliding toward extinction, and highlight the urgent need to expand efforts for ex situ captive breeding to bolster numbers in the wild and maintain captive insurance populations, and to protect vital habitat to safeguard the species' ongoing survival in the wild.     

Mussel beds on different types of structures support different macroinvertebrate assemblages

Abstract Artificial structures, such as seawalls, pilings and pontoons, are common features of urban estuaries. They replace natural structures or add to the amount of hard substratum in an area and provide habitats for many fish and invertebrates. Previous work has concentrated on fish or on the invertebrates that occupy the primary substratum of artificial structures. Mussels often grow on different types of structures (pontoons, pilings, seawalls and natural reefs) and provide a secondary substratum for other organisms to inhabit. Counting and identifying organisms associated with mussel beds is traditionally done to species level, which is very time‐consuming. To save time, organisms in this study were identified to coarse levels of taxonomic resolution (a mix of taxa, such as class, order, family and genus), which showed similar patterns to those when particularly speciose and abundant groups were identified to species. This study tests hypotheses that the distribution and abundance of mobile and sessile organisms that inhabit mussel beds will differ among natural and various types of artificial structures. When the associated assemblages of mussel beds from different types of structures and from different locations were examined, assemblages varied according to the type of structure they inhabited and its location. Assemblages associated with mussels on pontoons differed consistently from those on other types of structures. Patterns in the assemblages were also consistent through time. These data show that the types and amounts of artificial structures added to an environment can affect the types, distribution and abundances of organisms living in biogenic habitats.     

Hydrolysis of Galacto-oligosaccharides in Soymilk by κ-carrageenan-entrapped α-galactosidase from Aspergillus Oryzae

Summary α-Galactosidase was immobilized in κ-carrageenan. The optimum pH of the soluble enzyme and immobilized enzyme was 4.8. The optimum temperature of the soluble enzyme was 50 °C and that of the immobilized enzyme was increased to 53 °C. The immobilized enzyme was used in batch, repeated batch, and in the continuous mode to degrade the raffinose family sugars present in soymilk. Two hours incubation with free and immobilized α-galactosidase resulted in 88 and 75% reduction in raffinose family oligosaccharides in soymilk respectively. In the repeated batch, 61% reduction was obtained in the fourth cycle. A fluidized bed reactor was designed to treat soymilk continuously. The performance of immobilized α-galactosidase was also tested in a fluidized bed reactor at different flow rates and 92% reduction of raffinose family oligosaccharides in soymilk was obtained at 25 ml h⁻¹ flow rate. The study revealed that immobilized α-galactosidase in continuous mode is efficient in reducing the oligosaccharides present in the soymilk.     

混合床离子交换法对蛋白质溶液去离子

目的:探索一种能够在蛋白质不变性的前提下迅速而大量除去含蛋白质的溶液中无机离子的方法。方法:将001×7和201×7混合树脂应用于家兔全血细胞裂解液的去除无机离子过程,测定裂解液中无机离子被清除的程度,以及红细胞中乙酰胆碱酯酶的活性改变。结果:混合床离子交换法既能彻底清除裂解液中的无机离子,又能保留其中乙酰胆碱酯酶的活性。结论:在某些领域,混合床离子交换法是一种优越的去除蛋白质溶液中无机离子的方法。     

Innovative Techniques for Large‐scale Seagrass Restoration Using Zostera marina (eelgrass) Seeds

The use of Zostera marina (eelgrass) seeds for seagrass restoration is increasingly recognized as an alternative to transplanting shoots as losses of seagrass habitat generate interest in large‐scale restoration. We explored new techniques for efficient large‐scale restoration of Z. marina using seeds by addressing the factors limiting seed collection, processing, survival, and distribution. We tested an existing mechanical harvesting system for expanding the scale of seed collections, and developed and evaluated two new experimental systems. A seeding technique using buoys holding reproductive shoots at restoration sites to eliminate seed storage was tested along with new techniques for reducing seed‐processing labor. A series of experiments evaluated storage conditions that maintain viability of seeds during summer storage for fall planting. Finally, a new mechanical seed‐planting technique appropriate for large scales was developed and tested. Mechanical harvesting was an effective approach for collecting seeds, and impacts on donor beds were low. Deploying seed‐bearing shoots in buoys produced fewer seedlings and required more effort than isolating, storing, and hand‐broadcasting seeds in the fall. We show that viable seeds can be separated from grass wrack based on seed fall velocity and that seed survival during storage can be high (92–95% survival over 3 months). Mechanical seed‐planting did not enhance seedling establishment at our sites, but may be a useful tool for evaluating restoration sites. Our work demonstrates the potential for expanding the scale of seed‐based Z. marina restoration but the limiting factor remains the low rate of initial seedling establishment from broadcast seeds.     

Toxicants inhibiting anaerobic digestion: A review

Anaerobic digestion is increasingly being used to treat wastes from many sources because of its manifold advantages over aerobic treatment, e.g. low sludge production and low energy requirements. However, anaerobic digestion is sensitive to toxicants, and a wide range of compounds can inhibit the process and cause upset or failure. Substantial research has been carried out over the years to identify specific inhibitors/toxicants, and their mechanism of toxicity in anaerobic digestion. In this review we present a detailed and critical summary of research on the inhibition of anaerobic processes by specific organic toxicants (e.g., chlorophenols, halogenated aliphatics and long chain fatty acids), inorganic toxicants (e.g., ammonia, sulfide and heavy metals) and in particular, nanomaterials, focusing on the mechanism of their inhibition/toxicity. A better understanding of the fundamental mechanisms behind inhibition/toxicity will enhance the wider application of anaerobic digestion.