An integrative identification guide to the Hydrozoa (Cnidaria) of Bocas del Toro, Panama

This work is the first attempt to assess the biodiversity of the Hydrozoa in the Archipiélago de Bocas del Toro (Panamá, Caribbean Sea) using morphology and molecular taxonomy, and to produce field identification tools to help future identification and monitoring efforts in the area. We sampled, identified, vouchered, and barcoded 112 specimens of Hydrozoa from shallow coastal waters (0–22 m depth) in the Archipiélago de Bocas del Toro. The specimens belong to 70 taxa, of which 53 were identified at the species level, and 17 were identified at the genus or family level. We produced 64 sequences of the large ribosomal subunit of the mitochondrial RNA (mt lsu-rRNA, 16S), the genetic marker generally used for barcoding Hydrozoa. We updated the local checklist that now comprises 118 species, and produced 87 detailed taxon identification tables that display species descriptions augmented with pictures, geographic distribution (worldwide and in Bocas del Toro), GenBank accession numbers for the 16S mitochondrial gene, and a synopsis of the families they belong to

Variability in pigment composition and bio-optical characteristics of phytoplankton populations in the Atlantic basin

Understanding sources of variability in the optical properties of phytoplankton and how the properties vary over the global ocean is essential in the development of ocean-colour algorithms to map the distribution of phytoplankton functional groups. Using data from oceanographic cruises covering different biogeochemical biomes and provinces over a broad latitudinal gradient of the Atlantic Basin, this study examined the spatial distribution of phytoplankton diagnostic pigments and absorption coefficients and how they varied with ocean observables (temperature and chlorophyll-a concentration) that can be detected from space. It was found that variation in the chlorophyll a-specific absorption coefficient of phytoplankton at 440 nm, &amp;ast;ℎ(440), was influenced significantly by changes in the proportion of the non-photosynthetic pigment (NPP), whereas pigment indices of cell size showed only a weak correlation with &amp;ast;ℎ(440). There were province- and biome-specific changes in the relationships between both temperature and chlorophyll and &amp;ast;ℎ(440). This suggests that when developing remote-sensing algorithms that use temperature or chlorophyll as a predictor of phytoplankton size structure, the underlying physical oceanographic processes that control the biogeochemistry and ecology of the region should be taken into consideration.</p

Variability in pigment composition and bio-optical characteristics of phytoplankton populations in the Atlantic basin

Understanding sources of variability in the optical properties of phytoplankton and how the properties vary over the global ocean is essential in the development of ocean-colour algorithms to map the distribution of phytoplankton functional groups. Using data from oceanographic cruises covering different biogeochemical biomes and provinces over a broad latitudinal gradient of the Atlantic Basin, this study examined the spatial distribution of phytoplankton diagnostic pigments and absorption coefficients and how they varied with ocean observables (temperature and chlorophyll-a concentration) that can be detected from space. It was found that variation in the chlorophyll a-specific absorption coefficient of phytoplankton at 440 nm, &#119886;&ast;&#119901;&#8462;(440), was influenced significantly by changes in the proportion of the non-photosynthetic pigment (NPP), whereas pigment indices of cell size showed only a weak correlation with &#119886;&ast;&#119901;&#8462;(440). There were province- and biome-specific changes in the relationships between both temperature and chlorophyll &#119886; and &#119886;&ast;&#119901;&#8462;(440). This suggests that when developing remote-sensing algorithms that use temperature or chlorophyll as a predictor of phytoplankton size structure, the underlying physical oceanographic processes that control the biogeochemistry and ecology of the region should be taken into consideration.</p

Shipborne oceanic high-spectral-resolution lidar for accurate estimation of seawater depth-resolved optical properties

International audienceLidar techniques present a distinctive ability to resolve vertical structure of optical properties within the upper water column at both day-and night-time. However, accuracy challenges remain for existing lidar instruments due to the illposed nature of elastic backscatter lidar retrievals and multiple scattering. Here we demonstrate the high performance of, to the best of our knowledge, the first shipborne oceanic high-spectral-resolution lidar (HSRL) and illustrate a multiple scattering correction algorithm to rigorously address the above challenges in estimating the depth-resolved diffuse attenuation coefficient K d and the particulate backscattering coefficient b bp at 532 nm. HSRL data were collected during day-and night-time within the coastal areas of East China Sea and South China Sea, which are connected by the Taiwan Strait. Results include vertical profiles from open ocean waters to moderate turbid waters and first lidar continuous observation of diel vertical distribution of thin layers at a fixed station. The root-mean-square relative differences between the HSRL and coincident in situ measurements are 5.6% and 9.1% for K d and b bp , respectively, corresponding to an improvement of 2.7-13.5 and 4.9-44.1 times, respectively, with respect to elastic backscatter lidar methods. Shipborne oceanic HSRLs with high performance are expected to be of paramount importance for the construction of 3D map of ocean ecosystem