Ingestion of anthropogenic litter has been well documented in marine vertebrates, but comparatively little is known about marine invertebrates. We report macrolitter ingestion by the sandy anemone Bunodactis reynaudi at Muizenberg beach in False Bay, South Africa. Monthly surveys from May 2015 to August 2019 collected 491 ingested litter items (9.4 ± 14.9 items·month⁻¹, 39.8 ± 71.5 g·month⁻¹), of which >99% were plastic. The number of ingested items was correlated with the abundance of stranded items and ingestion peaked in autumn when seasonal rains washed more litter into the bay. Most ingested litter was clear (39%), white (16%) and black/purple (15%). Comparison with environmental litter showed selection for flexible plastics, particularly bags/packets and food packaging. Experimental feeding trials found that B. reynaudi selected for pieces of HDPE bag suspended in seawater for 2–20 days, suggesting that biofilms enhance the palatability of flexible plastics. Studies are needed to assess the possible impacts of plastic ingestion on B. reynaudi. While only a small proportion of the population currently ingest litter, ingestion might become more common if environmental litter loads increase. This might negatively affect the anemone’s ability to respond to other environmental changes such as increasing levels of heavy metal pollution.

The increase of annual organic wastes generated worldwide has become a major problem for many countries since the mismanagement could bring about negative effects on the environment besides, being costly for an innocuous disposal. Recently, insect larvae have been investigated to valorize organic wastes. This entomoremediation approach is rising from the ability of the insect larvae to convert organic wastes into its biomass via assimilation process as catapulted by the natural demand to complete its lifecycle. Among the insect species, black soldier fly or Hermetia illucens is widely researched since the larvae can grow in various environments while being saprophagous in nature. Even though black soldier fly larvae (BSFL) can ingest various decay materials, some organic wastes such as sewage sludge or lignocellulosic wastes such as waste coconut endosperm are destitute of decent nutrients that could retard the BSFL growth. Hence, blending with nutrient-rich low-cost substrates such as palm kernel expeller, soybean curd residue, etc. is employed to fortify the nutritional contents of larval feeding substrates prior to administering to the BSFL. Alternatively, microbial fermentation can be adopted to breakdown the lignocellulosic wastes, exuding essential nutrients for growing BSFL. Upon reaching maturity, the BSFL can be harvested to serve as the protein and lipid feedstock. The larval protein can be made into insect meal for farmed animals, whilst the lipid source could be extracted and transesterified into larval biodiesel to cushion the global energy demands. Henceforth, this review presents the influence of various organic wastes introduced to feed BSFL, targeting to reduce wastes and producing biochemicals from mature larvae through entomoremediation. Modification of recalcitrant organic wastes via fermentation processes is also unveiled to ameliorate the BSFL growth. Lastly, the sustainable applications of harvested BSFL biomass are as well covered together with the immediate shortcomings that entail further researches.

Concepts in microplastics studies are not well established due to the emerging nature of microplastic research, especially in jellyfish. We conducted experiments to test whether ephyrae would ingest more microbeads via trophic transfer than direct ingestion and whether medusae would ingest more aged microbeads than virgin microbeads. We exposed ephyrae of Aurelia coerulea to two treatments, aged microbeads and Artemia nauplii that had ingested microbeads. We found that the ephyrae ingested 35 times more microbeads via trophic transfer than by direct ingestion. In the second experiment, medusae of A. coerulea were exposed to virgin microbeads and microbeads in seawater under a 12/12 light/dark cycle or constant darkness. Ingestion rates of microbeads from the light incubation were greater than those from the dark incubation or virgin microbeads, suggesting the likely presence of photosynthetic organisms in biofilms from the light incubation increased the palatability of the microbeads and promoted their ingestion.

Ocean acidification (OA) can induce changes in marine organisms and species interactions. We examined OA effects on intertidal macroalgal growth, palatability, and consumption by a specialist crab (Pugettia producta) and a generalist snail (Tegula funebralis) herbivore. Moderate increases in pCO₂ increased algal growth in most species, but effects of pCO₂ on C:N and phenolic content varied by species. Elevated pCO₂ had no effect on algal acceptability to herbivores, but did affect their preference ranks. Under elevated pCO₂, electivity for a preferred kelp (Egregia menziesii) and preference rankings among algal species strengthened for both P. producta and T. funebralis, attributable to resilience of E. menziesii in elevated pCO₂ and to changes in palatability among less-preferred species. Preferred algae may therefore grow more under moderate pCO₂ increases in the future, but their appeal to herbivores may be strengthened by associated shifts in nutritional quality and defensive compounds in other species.

Butter clams, blue mussels, and Nuttall's cockle are important traditional food of the Gitga'at First Nation in Canada. Samples were collected and analyzed for polycyclic aromatic hydrocarbon (PAH) from the Gitga'at harvest sites from 2006 to 2015 to: 1) establish baseline conditions; 2) determine the likely source; 3) understand species specific response to spills; and 4) evaluate health risk associated with consumption. Baseline lipid normalized-total PAH in mussels was 2.36 (±2.86, 95%CI) μg/g in mussels, 3.26(±4.14) μg/g in clams and 3.98 (±4.98) μg/g in cockles. PAHs varied according to proximity to point sources and became less petrogenic through time. Concentrations of PAHs were elevated in all three species following diesel spills but returned to baseline levels within 5months. However, Gitga'at harvesters avoided bivalves from spill-affected habitats for several years because of their detection of reduced quality and palatability, highlighting the importance of incorporating local knowledge into future monitoring programs.

Global stressors like ocean acidification (OA) are expected to influence the quality or palatability of primary producers like algae. Such changes can trigger a response on algal consumers' feeding strategies, and this response may not necessarily be the same for the consumers during the ontogeny. We used a mesocosm's system to expose algae to current and projected OA conditions (390 and 1000ppm, respectively) and then compared the feeding behavior and absorption efficiency of juvenile and adult stages of the amphipod Orchestoidea tuberculata. Specifically, we measured consumption rates (with and without a choice) and absorption efficiency on algae exposed and not exposed to OA. Our results show that OA affect the amphipod's consumption and feeding preferences, and that these effects were related with the analyzed ontogenetic stage (juveniles versus adults). These results support the existence of an ontogenetic change in the response of this species and others similar marine invertebrates to OA, which highlight the need to incorporate different life stages in the study of OA or others global stressors.

Algae play an important role in ecological processes of aquatic ecosystems. Understanding the interactive effects of algae with invertebrates in litter decomposition is important for predicting the effects of global change on aquatic ecosystems. We manipulated Typha angustifolia litter to control exposure to shrimp fecal pellets and/or grazing, and the green alga Chlorella vulgaris were added to test their interactive effects on T. angustifolia litter decomposition. Our results showed that algae largely shortened microbial conditioning time and improved litter palatability (increasing litter quality), resulting in greater decomposition and higher fecal pellet production. Fecal pellets enhanced grazing effects on decomposition by increasing litter ash content. The effects of algae and especially fecal pellets on decomposition were dependent on or mediated by grazing. Without grazing, algae slightly promoted decomposition and marginally offset the negative effect of fecal pellets on litter decomposition. Shrimp grazing dramatically decreased microbial activity (extracellular enzyme activity and microbial respiration) at microbial conditioning stage while enhanced microbial activity after 84 days especially with both algae and fecal pellets present. Algae significantly upregulated N- and P-acquiring and slightly downregulated C-acquiring enzyme activity. Fecal pellets significantly depressed recalcitrant C-decomposition enzyme activity. Nevertheless, the three factors synergistically and significantly increased C loss and most enzyme activities, microbial respiration, and N immobilization, resulting in the decrease of litter C:N. Our results reveal the synergistic action of different trophic levels (autotrophs, heterotrophs, and primary consumers) in the complicated nutrient pathways of litter decomposition and provide support for predicting the effects of global changes (e.g., N deposition and CO₂ enrichment), which have dramatically effects on alga dynamics and on ecological processes in aquatic ecosystems.

Microalgae have been used as live food in aquatic species. In recent years, the interest in microalgae has considerably increased, thanks to the evolution of production techniques that have identified them as an ecologically attractive aquafeed ingredient. The present study provides the first data about the effects of dietary inclusion of a microalgae consortium grown in a high-rate algal pond system on zootechnical performance, morphometric indices, and dietary nutrient digestibility as well as morphology and functionality of the digestive system of European sea bass, Dicentrarchus labrax. A dietary treatment including a commercial mono-cultured microalgae (Nannochloropsis sp.) biomass was used for comparison. Six hundred and thirty-six European sea bass juveniles (18 ± 0.28 g) were randomly allotted into 12 experimental groups and fed 4 different diets for 10 weeks: a control diet based on fish meal, fish oil, and plant protein sources; a diet including 10% of Nannochloropsis spp. biomass (100 g/kg diet); and two diets including two levels (10% and 20%) of the microalgal consortium (100 and 200 g/kg diet). Even at the highest dietary inclusion level, the microalgal consortium (200 g/kg diet) did not affect feed palatability and fish growth performance. A significant decrease in the apparent digestibility of dry matter, protein, and energy was observed in diets including 10 and 20% of the microalgal consortium, but all fish exhibited a well-preserved intestinal histomorphology. Moreover, dietary inclusion with the microalgal consortium significantly increased the enzymatic activity of maltase, sucrase-isomaltase, and ɤ-glutamil transpeptidase in the distal intestine of the treated European sea bass. Algal consortium grown using fish farm effluents represents an attempt to enhance the utilization of natural biomasses in aquafeeds when used at 10 % as substitute of vegetable ingredients in diet for European sea bass.

High mixing ratios of ground-level O₃ threaten trophic interactions. In the present study, we conducted laboratory assays, where insect larvae and adults were not directly exposed to O₃, to test the feeding behavior and attraction of the coleopteran leaf beetle Agelastica coerulea to early and late leaves of Japanese white birch (Betula platyphylla var. japonica) treated with ambient or elevated O₃ levels. We found that overwintered adults were not deterred from grazing elevated O₃-treated leaves, but rather preferred them than ambient O₃-treated ones. We also found that the feeding behavior of 2nd instar larvae fed on early or late leaves was not influenced by the O₃ treatment of the leaves when larvae could choose leaves. These observations of the adults and larvae feeding preferences contradict prior observations in the field conditions where the insects avoided leaves in O₃-enriched atmosphere. Since adults preferred elevated O₃-exposed leaves in the present laboratory assays, it is worthy of further investigations whether adults change their grazing preference so as to ensure the leaf palatability as a feeding source for their larvae. Hence, new direction towards detailed ovipositional behavior surveys under field conditions is encouraged.

Historically, subsistence farmers around the Atlantic coast of NW Europe utilized marine algae as a fertilizer in agroecosystems, a practice that continued in small areas and is now considered to have real potential for re-establishing sustainable food production systems on marginal soils. Earthworms form a significant component of soil fauna, and their ecosystem services are well-documented. Therefore, palatability of marine organic amendments to faunal detritivores of terrestrial systems is of interest. This work aimed to assess the potential for growth of Aporrectodea caliginosa, Lumbricus rubellus and Aporrectodea longa fed with two common macroalgae (seaweeds), Laminaria digitata and Fucus serratus. In addition, choice chambers were constructed to permit earthworm selection of these macroalgae with more conventional organic materials, horse manure (HM) and birch leaves (BL). Over a period of 2 months, earthworm species showed significantly greater mass gain with conventional food (p < 0.05). Laminaria outperformed Fucus, which in turn was superior to soil alone. Similarly, when given a choice, a significant preference (p < 0.001) was shown for the more nitrogen-rich HM and BL over the seaweeds. No removal was recorded for A. caliginosa when offered seaweeds only. By contrast, L. rubellus and A. longa showed significant preferences (p < 0.001) for Laminaria over Fucus and fresh material over degraded. These results underline an interest to profit from natural resources (seaweeds) to maintain or improve soil biological quality in marginal coastal areas.