A conceptual framework to help choose appropriate blue nature-based solutions

Biodiversity loss and climate change have severely impacted ecosystems and livelihoods worldwide, compromising access to food and water, increasing disaster risk, and affecting human health globally. Nature-based Solutions (NbS) have gained interest in addressing these global societal challenges. Although much effort has been directed to NbS in urban and terrestrial environments, the implementation of NbS in marine and coastal environments (blue NbS) lags. The lack of a framework to guide decision-makers and practitioners through the initial planning stages appears to be one of the main obstacles to the slow implementation of blue NbS. To address this, we propose an integrated conceptual framework, built from expert knowledge, to inform the selection of the most appropriate blue NbS based on desired intervention objectives and social-ecological context. Our conceptual framework follows a four incremental steps structure: Step 1 aims to identify the societal challenge(s) to address; Step 2 highlights ecosystem services and the underlying biodiversity and ecological functions that could contribute to confronting the societal challenge(s); Step 3 identify the specific environmental context the intervention needs to be set within (e.g. the spatial scale the intervention will operate within, the ecosystem's vulnerability to stressors, and its ecological condition); and Step 4 provides a selection of potential blue NbS interventions that would help address the targeted societal challenge(s) considering the context defined through Step 3. Designed to maintain, enhance, recover, rehabilitate, or create ecosystem services by supporting biodiversity, the blue NbS intervention portfolio includes marine protection (i.e., fully, highly, lightly, and minimally protected areas), restorative activities (i.e., active, passive, and partial restoration; rehabilitation of ecological function and ecosystem creation), and other management measures (i.e., implementation and enforcement of regulation). Ultimately, our conceptual framework guides decision-makers toward a versatile portfolio of interventions that cater to the specific needs of each ecosystem rather than imposing a rigid, one-size-fits-all model. In the future, this framework needs to integrate socio-economic considerations more comprehensively and be kept up-to-date by including the latest scientific information.

A comparison of Landsat 8, RapidEye and Pleiades products for improving empirical predictions of satellite-derived bathymetry

Satellite derived bathymetry (SDB) enables rapid mapping of large coastal areas through measurement of optical penetration of the water column. The resolution of bathymetric mapping and achievable horizontal and vertical accuracies vary but generally, all SDB outputs are constrained by sensor type, water quality and other environmental conditions. Efforts to improve accuracy include physics-based methods (similar to radiative transfer models e.g. for atmospheric/vegetation studies) or detailed in-situ sampling of the seabed and water column, but the spatial component of SDB measurements is often under-utilised in SDB workflows despite promising results suggesting potential to improve accuracy significantly. In this study, a selection of satellite datasets (Landsat 8, RapidEye and Pleiades) at different spatial and spectral resolutions were tested using a log ratio transform to derive bathymetry in an Atlantic coastal embayment. A series of non-spatial and spatial linear analyses were then conducted and their influence on SDB prediction accuracy was assessed in addition to the significance of each model's parameters. Landsat 8 (30 m pixel size) performed relatively weak with the non-spatial model, but showed the best results with the spatial model. However, the highest spatial resolution imagery used - Pleiades (2 m pixel size) showed good results across both non-spatial and spatial models which suggests a suitability for SDB prediction at a higher spatial resolution than the others. In all cases, the spatial models were able to constrain the prediction differences at increased water depths.

Life cycle inference and phylogeny of Ortholinea labracis n. sp. (Myxosporea: Ortholineidae), a parasite of the European seabass Dicentrarchus labrax (Teleostei: Moronidae), in a Portuguese fish farm

Ortholinea labracis n. sp. is described and its life cycle is inferred from a Southern Portuguese fish farm, with basis on microscopic and molecular procedures. This myxosporean parasite infects the urinary bladder of the European seabass Dicentrarchus labrax and the intestinal epithelium of a marine oligochaete of the genus Tectidrilus. Myxospores subspherical in valvular view and ellipsoidal in sutural view measuring 7.6 ± 0.3 (6.8-8.7) μm in length, 7.2 ± 0.2 (6.7-7.7) μm in width and 6.5 ± 0.4 (5.8-7.7) μm in thickness. Two polar capsules, 3.0 ± 0.2 (2.6-3.4) μm long and 2.4 ± 0.1 (2.0-2.9) μm wide, located at the same level, but with divergent orientation and opening to opposite sides of the suture line. Sequencing of the SSU rRNA gene revealed a similarity of 100% between the analysed myxospores and triactinomyxon actinospores. The phylogenetic setting of O. labracis n. sp. shows subgrouping in correlation with tissue tropism, but identifies this parasite as another exception to the main division of Myxosporea into the main freshwater and marine lineages.

Ultrastructure and phylogeny of the parasite Henneguya carolina sp. nov. (Myxozoa), from the marine fish Trachinotus carolinus in Brazil

Microscopic and molecular procedures are used to describe a new myxosporean species, Henneguya carolina sp. nov., found infecting the intestine of the marine teleost fish Trachinotus carolinus on the southern Atlantic coast of Brazil. Spherical to ellipsoid cysts, measuring up to ~750 µm, display synchronous development. Mature myxospores are ellipsoidal with a bifurcated caudal process. Myxospore body length, width, and thickness are 12.7 ± 0.8 (12.0-13.4) µm, 8.8 ± 0.6 (7.5-9.6) µm, and 5.8 ± 0.4 (5.0-6.4) µm, respectively; 2 equal caudal processes are 16.8 ± 1.1 (15.9-18.0) µm long, and the total myxospore length is 29.4 ± 0.8 (28.4-30.4) µm. Two pyriform polar capsules measure 5.0 ± 0.5 (4.6-5.6) × 2.4 ± 0.4 (1.9-2.9) µm, and each contains a polar filament forming 3 to 4 coils. Sporoplasm is binucleated and presents a spherical vacuole surrounded by numerous globular sporoplasmosomes. Molecular analysis of the small subunit rRNA gene by maximum parsimony, neighbor joining, and maximum likelihood reveals the parasite clustering together with other myxobolids that are histozoic in marine fish of the order Perciformes, thereby strengthening the contention that the host phylogenetic relationships and aquatic environment are the strongest evolutionary signal for myxosporeans of the family Myxobolidae.

Ultrastructure of novel thrombocytes in the dog snapper Lutjanus jocu

Myxosporean cysts containing spores of Henneguya sp. were observed in the gills of the dog snapper Lutjanus jocu. Adjacent to the cysts were capillaries, allowing observation of peripheral blood cells. Numerous white blood cells displaying uncommon cytoplasmic projections were observed amongst the erythrocytes. Their morphology allowed them to be identified as thrombocytes (TCs). Each TC displayed 18-26 cytoplasmic projections, most of which were in close proximity to erythrocytes. At their apical end, each cytoplasmic projection presented an ellipsoidal vacuole (c. 0·6 µm × 0·3 µm) from which a secretory tubule, 0·3-0·4 µm long and c. 120 nm in total diameter, extended towards the periphery of the TC plasmalemma and fused with the cellular membrane. From this opening, contents of vacuoles were apparently released into the lumen of the capillaries. Other vacuoles with similar features, and containing an electron-lucent matrix, were observed in the cytoplasm of the TC. This is the first description of fish TC with these ultrastructural features and organization, which suggest that they perform a secretory function.

Morphological and molecular characterization of a new myxozoan species (Myxosporea) infecting the gall bladder of Raja clavata (Chondrichthyes), from the Portuguese Atlantic Coast

Microscopic and molecular procedures are used to describe a new myxosporean species, Chloromyxum clavatum n. sp., infecting the cartilaginous fish Raja clavata Linnaeus, 1758 (Chondrichthyes: Rajidae), collected from the northwest Atlantic coast of Portugal. Young plasmodia and mature spores were found floating free in the gall bladder of R. clavata . Spores were spherical to subspherical with a pointed anterior end, measuring14.4 ± 0.5 μm (n = 25) in length, 11.9 ± 0.5 μm (n = 25) in width, and 9.4 ± 0.5 μm (n = 15) in thickness. The spore's wall was composed of 2 equally sized valves, each displaying 6-8 elevated surface ridges and a bundle of several tapering caudal filaments attached to the basal portion. Spores contained 4 pyriform equally sized polar capsules (5.5 ± 0.4 μm × 2.9 ± 0.5 μm) (n = 25), each possessing an obliquely arranged isofilar polar filament coiled in 7-8 coils. Morphological data, host specificity, tissue tropism, and molecular analysis of the SSU rDNA gene identify this parasite as a new species of Chloromyxum. Neighbor-joining and maximum likelihood further reveal the parasite clustering with other species of Chloromyxum infecting the gall bladder of marine cartilaginous fish to form a clade positioned at the base of the freshwater clade, therefore constituting an exception to the major division of the class Myxosporea into the freshwater and marine clades, while supporting the existence of a correlation between tissue tropism and myxosporean phylogeny.

Ultrastructural and molecular characterization of a new microsporidium parasite from the Amazonian fish, Gymnorhamphichthys rondoni (Rhamphichthyidae)

A new species of a microsporidium found in the freshwater teleost Gymnorhamphichthys rondoni, collected on the lower Amazon River, is described based on light, ultrastructural, and phylogenetic studies. This parasite develops in the skeletal muscle of the abdominal cavity, forming whitish cyst-like structures containing numerous spores. Mature spores, lightly pyriform to ellipsoidal with rounded ends and measuring 4.25 ± 0.38 × 2.37 ± 0.42 µm (n  =  30), were observed. The spore wall, which measured about 102 nm, was composed of 2 layers with approximately the same thickness. The isofilar polar filament was coiled, with 9-10 (rarely 8) turns. The posterior vacuole appeared as a pale area, occupying about 1/3 of the spore length, and contained a spherical posterosome composed of granular material that was denser at the periphery. The myofibrils located near the spores appeared to be in advanced degradation. Molecular analysis of the rRNA genes, including the ITS region, and phylogenetic analyses using maximum parsimony, maximum likelihood, and Baysesian inference were performed. The ultrastructural characteristics of the spores and the phylogenetic data strongly suggested that it is a new species related to Kabatana, Microgemma, Potaspora, Spraguea, and Tetramicra. We named this new microsporidian from Amazonian fauna as Kabatana rondoni n. sp.

Light and electron microscopic study of the myxosporean, Henneguya friderici n. sp. from the Amazonian teleostean fish, Leporinus friderici

A new histozoic species of myxosporean was found to infect the gill filaments, gut, kidney and liver of the freshwater teleost Leporinus friderici, collected from the estuarine region of the Amazon, near the city of Belém, Brazil. The plasmodia show asynchronous development, at any one time composed of mature spores and all sporogonic stages. The ellipsoidal spore body, measuring 10.4 microm long and 5.7 microm wide, consists of 2 equal shell valves adhering together along the straight suture line. Each valve has a caudal process measuring 23.3 microm in length. There are 2 symmetric polar capsules, without intercapsular appendix, measuring 5.0 microm x 2.1 microm, and each has a polar filament with 7-8 coils. In general, ultrastructural details of sporoblast and spore development are in agreement with previously described myxosporeans. Some ultrastructural aspects such as cellular alterations of the pericyte in the different organs infected and characterization of the sporoplasmosomes during the sporoplasm maturation are described. This parasite was studied under light and electron microscope and compared with others species of the genus Henneguya, considering also host specificity. From our observations we propose the creation of a new species, Henneguya friderici n. sp.

Ultrastructural data on the spore of Myxobolus maculatus n. sp. (phylum Myxozoa), parasite from the Amazonian fish Metynnis maculatus (Teleostei)

Light and electron microscopy studies of a myxosporean, parasitic in the intertubular interstitial tissue of the kidney of the freshwater teleost fish Metynnis maculatus Kner, 1860 (Characidae) from the lower Amazon River (Brazil), are described. We observed polysporic histozoic plasmodia delimited by a double membrane and with several pinocytic channels and containing several life cycle stages, including mature spores. The spore body was of pyriform shape and was 21.0 microm long, 8.9 microm wide and 7.5 microm thick. Elongated-pyriform polar capsules were of equal size (12.7 x 3.2 microm) and contained a polar filament with 14 or 15 coils. The spore features fit those of the genus Myxobolus. Densification of the capsular primordium matrix, which increased in density from the inner core outwards, differentiating at the periphery into small microfilaments measuring 45 nm each, and tubuli arranged in aggregates and dispersed within the capsular matrix of the mature spores, are described. Based on the morphological differences and specificity of the host, we propose the creation of a new species named Myxobolus maculatus n. sp.

Apathetic thyrotoxicosis

Apathetic thyrotoxicosis is an atypical though not rare manifestation of hyperthyroidism. The cardinal features are apathy and depression, as opposed to hyperkinesis and mental alertness in the usual thyrotoxic patient, and are unassociated with the usual signs and symptoms of hyperthyroidism, making the diagnosis difficult. We report three cases of apathetic thyrotoxicosis seen during one year.