The effects that ultraviolet radiation (UVR, 280 to 400 nm) and photosynthetically active radiation (PAR, 400 to 700 nm) had on early life stages of Mastocarpus stellatus and Chondrus crispus were studied to determine if differences in UVR tolerance could influence their recruitment success on the upper eulittoral shores of Helgoland (North Sea). Photosynthesis, germination capacity, DNA damage...

We present a new dynamic model that uses a small number of prescribed parameters to predict the chlorophyll a:carbon ratio and growth rate of phytoplankton in both constant and varying irradiance. The model provides a self-contained description of energy and mass fluxes and regulation of partitioning of photosynthate during phytoplankton adaptation to irradiance. The kinetics and steady-state o...

Deposition rates were measured by means of sediment traps at five stations in hypertrophic Takahamairi Bay of Lake Kasumigaura for the selected periods of 1981-1986. Separation of deposited fluxes into autochthonous and sediment resuspension components was attempted on the basis of chlorophyll a concentration for the tracer. Even at the central station of the bay, the average daily flux of auto...

A long-term record of Asian dust storms showed seven high-occurrence-frequency centers in China. The intrusion of Asian dust into the downwind seas, including the China seas, the Sea of Japan, the subarctic North Pacific, the North Pacific subtropical gyre, and the western and eastern Equatorial Pacific, has been shown to add nutrients to ocean ecosystems and enhance their biological activities...

Ferredoxin (Fd) is surface active; both its area/molecule, A, and surface potential, AV, (at an air-water interface) vary with the pH of the subphase. From the surface isotherms (at pH 7.7) A and AV are 167 Ä2 and 170 + 20mV, respectively, when the surface tension is 10 dyne/cm. Fd and chlorophyll a (Chi) appear to form a mixed monomolecular film. At pH 7.7 a maximum interaction between Fd and ...

Pigment-based chemotaxonomy and CHEMTAX software have proven to be a valuable phytoplankton monitoring tool in marine environments, but are yet underdeveloped to determine algal assemblages in freshwater ecosystems. The main objectives of this study were (1) to compare the results of direct microscopy and CHEMTAX in describing phytoplankton community composition dynamics in a large, shallow and...

Seasonal and inter-annual variability in satellite-derived estimates of near-surface chlorophyll a concentration and primary production were examined in three regimes (shelf, slope and deep oceanic waters) off Washington and Vancouver Island from 1998 to 2002. Wind-induced upwelling predominates in late spring and summer, coinciding with the maximum in solar radiation, leading to increased accu...

Although species commonly modify habitats and thereby influence ecosystem structure and function, the factors governing the ecological importance of these modifications are not well understood. Pacific salmon have repeatedly been shown to positively influence the abundance of benthic biota by annually transferring large quantities of nutrients from marine systems to the nutrient-poor freshwater...

In the photosynthetic membrane, there is a particular aggregated state for the chlorophyll a (Chl a) molecules with a specific arrangement responsible for the high efficiency of energy conversion. Chl a monolayers, transferred onto solid substrates, are systems that potentially can mimic the packing of the in vivo system. The association of Chl a in the monolayer results in the formation of dim...

The detection and prediction of changes in coastal ecosystems require a better understanding of the complex physical, chemical and biological interactions, which involves that observations should be performed continuously. For this reason, there is an increasing demand for small, simple and cost-effective in situ sensors to analyze complex coastal waters at a broad range of scales. In this cont...