An evaluation of ocean color model estimates of marine primary productivity in coastal and pelagic regions across the globe

Nearly half of the earth's photosynthetically fixed carbon derives from the oceans. To determine global and region specific rates, we rely on models that estimate marine net primary productivity (NPP) thus it is essential that these models are evaluated to determine their accuracy. Here we assessed the skill of 21 ocean color models by comparing their estimates of depth-integrated NPP to 1156 in situ C-14 measurements encompassing ten marine regions including the Sargasso Sea, pelagic North Atlantic, coastal Northeast Atlantic, Black Sea, Mediterranean Sea, Arabian Sea, subtropical North Pacific, Ross Sea, West Antarctic Peninsula, and the Antarctic Polar Frontal Zone. Average model skill, as determined by root-mean square difference calculations, was lowest in the Black and Mediterranean Seas, highest in the pelagic North Atlantic and the Antarctic Polar Frontal Zone, and intermediate in the other six regions. The maximum fraction of model skill that may be attributable to uncertainties in both the input variables and in situ NPP measurements was nearly 72%. on average, the simplest depth/wavelength integrated models performed no worse than the more complex depth/wavelength resolved models. Ocean color models were not highly challenged in extreme conditions of surface chlorophyll-a and sea surface temperature, nor in high-nitrate low-chlorophyll waters. Water column depth was the primary influence on ocean color model performance such that average skill was significantly higher at depths greater than 250 m, suggesting that ocean color models are more challenged in Case-2 waters (coastal) than in Case-1 (pelagic) waters. Given that in situ chlorophyll-a data was used as input data, algorithm improvement is required to eliminate the poor performance of ocean color NPP models in Case-2 waters that are close to coastlines. Finally, ocean color chlorophyll-a algorithms are challenged by optically complex Case-2 waters, thus using satellite-derived chlorophyll-a to estimate NPP in coastal areas would likely further reduce the skill of ocean color models.

Cranial morphology and karyotypic analysis of Ceratophrys joazeirensis (Anura: Ceratophryidae, Ceratophrynae): Taxonomic considerations

The frog species Ceratophrys joazeirensis Mercadal, 1986 is only known from the Caatinga (semi-arid savanna) and, until recently, from the type locality of Juazeiro, State of Bahia, Brazil. It has now also been found in the States of Paraíba and Rio Grande do Norte, in environments of hypoxerophylic Caatinga. Cytogenetic and comparative analysis of the cranial morphology of C. joazeirensis and C. aurita (Raddi, 1823) were undertaken. The karyotype of the species is also shown for the first time. The results show important differences in the cranial morphology between C. joazeirensis (8n) and C. aurita (8n), species whose areas of distribution (Caatinga and Northeast Atlantic forest, respectively) are contiguous. The chromosomes of C. joazeirensis show similar size and morphology to the ones of C. aurita (C. dorsata), C. ornata Bell, 1843 (8n) and C. cranwelli Barrio, 1980 (2n). Such data would be in agreement with the opinion of some authors who consider these species to constitute a monophyletic group. Copyright © 2006 Magnolia Press.