Carbon sequestration and geochronology in Southern England’s seagrass meadows

The aim of this study was to provide an evaluation of the current methods used to assess carbon sequestration (Cseq) rates from intertidal Zostera spp. meadows in central Southern England. This study evaluated the use of 210Pb dating methods to calculate sediment accretion rates from four intertidal seagrass meadows along the southern central coast of England. Results obtained were then used to determine Cseq rates, following different models. The mean rate of Cseq calculated in this study using the CRS model was 75.12 g m-2 year-1, comparable to other global regions and within the estimated global range. However, results revealed that other, conservative methods, provide much lower Cseq rates, highlighting the need for caution when choosing appropriate methods and reporting results related to seagrass carbon sequestration potential. Moreover, these results highlight the importance of local assessments of Cseq, and the need to create robust models that include the effects of mixing, erosion, and disturbance, to better understand the possible effects of extreme climate events and anthropogenic impacts on seagrass ecosystems' carbon sequestration potential

Feeding strategies and energy to protein ratio on tambaqui performance and physiology

O objetivo deste trabalho foi avaliar o efeito da privação alimentar e da realimentação com dietas contendo diferentes relações entre energia e proteína (E/P) sobre o desempenho e a fisiologia de juvenis de tambaqui (Colossoma macropomum). Utilizou-se arranjo fatorial 4x2 com três repetições, com quatro relações E/P (11,5, 10,5, 9,5 e 8,5 kcal g‑1 de energia digestível por proteína) e dois regimes alimentares (com e sem privação), durante 60 dias. Peixes do grupo com privação alimentar permaneceram em jejum por 14 dias e foram realimentados do décimo quinto ao sexagésimo dia, enquanto os demais foram alimentados por 60 dias. Ao final do período experimental, o peso dos peixes submetidos à privação alimentar foi menor do que o dos alimentados continuamente; entretanto, esta condição não influenciou os parâmetros fisiológicos avaliados. Tambaquis alimentados com 11,5 kcal g‑1 obtiveram menor peso que os alimentados com as demais dietas, em ambos os regimes. Entre os parâmetros fisiológicos, apenas a proteína plasmática apresentou aumento significativo nos peixes alimentados com 8,5 kcal g‑1, em ambos os regimes alimentares, provavelmente em razão da maior concentração de proteína na dieta. Esses resultados mostram que os peixes apresentam crescimento compensatório parcial em todos os tratamentos, e que 10,5 kcal g‑1 pode ser recomendada para a dieta de juvenis de tambaqui.The objective of this work was to evaluate the effect of feed deprivation and refeeding with diets containing different energy to protein ratios (E/P) on the performance and physiology of juvenile tambaqui (Colossoma macropomum). A 4x2 factorial arrangement with three replicates was used, with four E/P ratios (11.5, 10.5, 9.5, and 8.5 kcal g‑1 digestible energy per protein) and two feeding regimens (with and without deprivation), during 60 days. Fish from the food‑deprived group were fasted for 14 days and refed from the fifteenth to the sixtieth day, whereas the remaining fish were fed for 60 days. At the end of the experimental period, weight of fish subjected to food deprivation was lower than that of those continuously fed; however, this condition did not influence the physiological parameters analyzed. Tambaqui fed 11.5 kcal g‑1 achieved lower final weight than those fed with the other diets, in both regimens. Among the physiological parameters, only plasma protein presented significant increase in fish fed 8.5 kcal g‑1, in both feeding regimens, probably due to the higher dietary protein concentration. These results indicate that fish show a partial compensatory growth, and that 10.5 kcal g‑1 can be recommended for the diet of juvenile tambaqui

Feeding strategies and energy to protein ratio on tambaqui performance and physiology

The objective of this work was to evaluate the effect of feed deprivation and refeeding with diets containing different energy to protein ratios (E/P) on the performance and physiology of juvenile tambaqui (Colossoma macropomum). A 4x2 factorial arrangement with three replicates was used, with four E/P ratios (11.5, 10.5, 9.5, and 8.5 kcal g-1 digestible energy per protein) and two feeding regimens (with and without deprivation), during 60 days. Fish from the food-deprived group were fasted for 14 days and refed from the fifteenth to the sixtieth day, whereas the remaining fish were fed for 60 days. At the end of the experimental period, weight of fish subjected to food deprivation was lower than that of those continuously fed; however, this condition did not influence the physiological parameters analyzed. Tambaqui fed 11.5 kcal g-1 achieved lower final weight than those fed with the other diets, in both regimens. Among the physiological parameters, only plasma protein presented significant increase in fish fed 8.5 kcal g-1, in both feeding regimens, probably due to the higher dietary protein concentration. These results indicate that fish show a partial compensatory growth, and that 10.5 kcal g-1 can be recommended for the diet of juvenile tambaqui

Farelo de soja e farelo de castanha da Amazônia como substituto da proteína animal na dieta de juvenis de matrinxã: aspectos zootécnicos, fisiológicos e econômicos

Matrinxã (Brycon amazonicus) is a species native from the Amazon Basin whith omnivorous feeding habit, which has high commercial value. Features such as rapid growth, rusticity and acceptability of artificial food highlight this species for breeding in intensive cropping systems. The food may correspond to up to 70% of production costs, the protein represented by the fish meal the most expensive nutrient. In order to reduce costs of production plants has sought alternative sources to replace fish meal in the formulation of commercial diets. This work verified the feasibility of inclusion of increasing levels of soybean meal (Glicine max) meal and brown of the Amazon (Bertholletia excelsa) in the diet of juvenile matrinxã, evaluating parameters zootechnical, physiological and comparing the costs of each experimental diet . In this experiment 420 fish were distributed in 21 tanks of pvc in a completely randomized design with seven treatments, C0, C15, C30, C45, S15, S30 and S45, corresponding to the control and treatment with replacement of fishmeal by increasing levels (15, 30 and 45%) of replacement of fishmeal by soybean meal and brown respectively. For the variables analyzed, no significant difference between treatments, indicating that it is possible to include up to 45% of the Amazon nut meal in diets for juvenile matrinxã without harming the performance of fish, and no change in their physiological indicators of stress.O Matrinxã (Brycon amazonicus) é uma espécie nativa da Bacia Amazônica de hábito alimentar onívoro, que possui elevado valor comercial. O rápido crescimento, rusticidade e aceitabilidade de alimento artificial destacam esta espécie para criação em sistema intensivo. A alimentação pode corresponder a 70% dos custos de produção, sendo a proteína representada pela farinha de peixe o alimento mais oneroso. Com a finalidade de reduzir os custos da produção tem se buscado fontes vegetais alternativas para substituir a farinha de peixe na formulação de rações comerciais. Neste trabalho verificou-se a viabilidade da inclusão de níveis crescentes de farelo de soja (Glicine max) e farelo de castanha da Amazônia (Bertholletia excelsa) na ração de juvenis de matrinxã, avaliando parâmetros zootécnicos, fisiológicos e comparando os custos de cada ração experimental. Neste experimento 420 peixes foram distribuídos em 21 tanques de PVC, em um delineamento experimental inteiramente casualizado, com sete tratamentos, C0, C15, C30, C45, S15, S30 e S45, correspondendo ao controle e aos tratamentos com substituição da farinha de peixe por níveis crescentes (15, 30 e 45%) de substituição da farinha de peixe pelos farelos de castanha e soja, respectivamente. Para as variáveis analisadas, não houve diferença significativa entre tratamentos, indicando que é possível a inclusão de até 45% do farelo de castanha da Amazônia em rações para juvenis de matrinxã, sem prejudicar a performance dos peixes e sem alteração de seus parâmetros fisiológicos indicadores de estresse

Carbon stocks in southern England's intertidal seagrass meadows

This study analyses total carbon stock (Cstocks) from the Isle of Wight, Solent, and adjacent harbours in southern England, including organic carbon (Corg) stored in the sediment and plant. Results from this study contribute to global blue carbon research by reporting the first direct assessment of sediment Cstocks in the top metre of intertidal seagrass meadows from the Solent region, with significant Cstocks, on average 103.12 ± 71.45 MgC ha−1, comparable to other global regions. This study also compared sediment %Corg and percentage of organic matter (%OM) within seagrass meadows and adjacent, un-vegetated, sampling points, showing that un-vegetated mudflats had higher %Corg and %OM than seagrass for most sites, apart from Hayling Island. This study shows that %OM can be confidently used as a proxy to determine sediment %Corg values in intertidal seagrass meadows. These results support the inclusion of the region's seagrass meadows in conservation and restoration projects, aiming not only to conserve the C stored in their soils, but also increase their future C uptake potential

Composition and abundance of fishes in the interface between open water and macrophyte banks, and the dynamics of this interface during morning and evening twilight, in lake Catalão, Amazonas, Brazil

This work studied the composition and abundance of the fishes that move between macrophyte banks and open water during the morning twilight (CM) and afternoon twilight (CV). The collections were made using gillnets, along banks of Paspalum repens, at Catalão lake, in Amazonas, Brazil. A total of 222 individuals and 37 species were collected. Of these, 130 individuals were collected during the CM and 92 during the CV; 80 individuals were leaving during the CM and 40 individuals were leaving during the CV. Auchenipterus nuchalis, Pellona castelnaeana, Triportheus angulatus and T. albus were the most common and concentrated species collected in the CM and Pimelodus blochii was the most common species collected in the CV

A review of seagrass ecosystem services: providing nature-based solutions for a changing world

Seagrasses are marine flowering plants, which form extensive meadows in intertidal and shallow water marine environments. They provide a wide range of ecosystem services, which directly or indirectly benefit humans and can be grouped into four broad categories: provisioning (e.g. food production); regulating (e.g. carbon sequestration); supporting (e.g. primary production); and cultural (e.g. recreational, and eco-tourism). This study provides a review of publications focusing on seagrass ecosystem services provision to identify knowledge gaps and improve our understanding of the use of these habitats as nature-based solutions to societal challenges, such as climate change. Results showed that some ecosystem services, namely food provision, carbon sequestration, and maintenance of biodiversity/nursery habitats receive a higher level of focus and attention than others, such as regulation of diseases and social relations, which are rarely, if ever, included in studies. It is clear that in order to fully comprehend the nature-based solution potential held by seagrass ecosystems, studies need to consider ecosystem services as a whole, and also combine and share results across global regions, to better understand the potential impacts of degradation and loss of these ecosystems worldwide. Suggestions include applying novel technologies such as remote sensing and ecological niche modelling to address some of the main gaps in seagrass research, like meadow extent and connectivity within landscapes, to better incorporate preservation of seagrass ecosystems in marine management plans

Respostas fisiológicas e desempenho do tambaqui alimentado com dietas suplementadas com castanha da Amazônia

The present study evaluated the effectiveness of Amazonian nut (Bertholletia excelsa) as an alternative source of vegetal protein in tambaqui (Colossoma macropomum) diet. Performance and physiological status of fish fed for 60 days were evaluated. Four experimental isonitrogenous diets with 36% crude protein were formulated with increasing levels of nut meal (0, 10, 20 and 30%). Results showed the same growth performance for fish fed with diet with different levels of Amazonian nut than that without this ingredient (control). Analysis of physiological parameters (hematocrit, erythrocyte number, hemoglobin concentration, hematimetric indexes, total plasma protein and plasma glucose) corroborate these results, with no significant differences among treatments. Therefore, adding up to 30% of Amazonian nut in tambaqui diet there is no negative effect on physiological homeostasis and growth performance, indicating that the Amazonian nut is a promising alternative dietary protein source ingredient for tambaqui