Submerged aquatic vegetation can dramatically alter the drag, turbulence and diffusivity characteristics of flow in aquatic systems. As a result, the diffusion and advection of contaminants and particulates are greatly influenced. However, modeling efforts generally treat submerged vegetation merely as a source of drag. This study explores the idea that flow through submerged aquatic vegetation...

Callitriche cophocarpa Sendtner is a heterophyllous amphibious macrophyte that produces apical rosettes of floating leaves. The importance of air contact for inorganic carbon and N uptake and for growth was investigated. Plants were grown with the floating rosette in contact with air of various humidities (10, 50, and >90% relative humidity) and with the submerged parts in N-free water at 350 [...

One of the best known crustacean hormones is the crustacean hyperglycemic hormone (CHH). However, the mechanisms involved in hormone release in these animals are poorly understood, and thus constitute the central objective of the present study. Different groups of crustaceans belonging to diverse taxa (Chasmagnathus granulata, a grapsid crab and Orconectes limosus, an astacid) were injected wit...

Submerged aquatic invasive plant species are increasingly being recognised as a major threat to South African water ways. Pet stores, aquarists and the internet-mediated trade were investigated as pathways for submerged invasive macrophyte introductions into South Africa. Online and manually distributed surveys were used to determine the extent of movement of invasive as well as indigenous subm...

The biological effects of inhalable nanoparticles have been widely studied in vitro with pulmonary cells cultured under submerged and air-liquid interface (ALI) conditions. Submerged exposures are experimentally simpler, but ALI exposures are physiologically more realistic and hence potentially biologically more meaningful. In this study, we investigated the cellular response of human alveolar ...

The purpose of the study was to evaluate the load output of a pressure sensor in the presence of liquid saturation in a controlled environment. We hypothesized that a calibrated pressure sensor would provide diminishing load outputs over time in controlled environments of both humidified air and while submerged in saline and the sensors would reach a steady state output once saturated. A consis...

Submerged marine forests of macroalgae known as kelp are one of the key structures for coastal ecosystems worldwide. These communities are responding to climate driven habitat changes and are therefore appropriate indicators of ecosystem status and health. Hyperspectral remote sensing provides a tool for a spatial kelp habitat mapping. The difficulty in optical kelp mapping is the retrieval of ...

Extrapolation of results from empirical studies of natural or anthropogenic perturbations are a useful tool in estimating potential effects of future impacts, For 5 years we studied the direct effects of a major oil spill on fringing red mangroves (Rhizophora mangle) and the organisms that live attached to their submerged prop roots, Based on these data, we here estimate the effects of this oil...

In filamentous fungi, secondary metabolism is often linked with developmental processes such as conidiation. In this study we analyzed the link between secondary metabolism and conidiation in the main industrial producer of the β-lactam antibiotic penicillin, the ascomycete Penicillium chrysogenum. Therefore, we generated mutants defective in two central regulators of conidiation, the transcrip...

Significant numbers of bird species forage on the tubers of the submerged aquatic species. This resource is difficult to map due to the submerged nature of these species. Because the temperature is the primary driving factor of photosynthesis in these vegetation species, it is possible to map the distribution and biomass production of these submerged species indirectly. For the relative short g...