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The integument of marine mammals provides an ideal substrate for colonization by photosynthetic epizoans. A review of the literature and new data from the harbor seal (Phoca vitulina richardsi) revealed at least eight genera of photosynthetic cyanobacteria and algae colonizing the pelage of six species of pinnipeds. The relationship may be considered a facultative association, beneficial to the photosynthetic epizoans and relatively neutral (but perhaps slightly costly) to their mammalian hosts. We studied the incidence of algal growth on the pelage of harbor seals in central California during 1985–1987 and 2017. The green alga Ulva sp. occurred on adult females throughout the year and rarely occurred on adult males. Algal growth appeared to be most frequent during the breeding season (February to May) and least frequent during the molt and post-molt seasons (June to October). Algal growth occurred more frequently on harbor seals in estuaries than along the coast. Much remains to be learned about the colonization of pinnipeds by photosynthetic epizoans and why some seals are more susceptible to colonization by algae than others. [ABSTRACT FROM AUTHOR]

Cyanobacteria and algae are problematic in California rice fields that are typically shallow and have high nutrient levels, providing ideal growing conditions. Nostoc spongiaefbrme is a problem because extensive floating mats dislodge rice seedlings or smother them when the mats accumulate in windward areas. There is little published information on growth requirements for N. spongiaeforme. We grew N. spongiaeforme in BG-11 medium at 24 combinations of light (22, 87, 162, and 400 µM m-2s-1) and temperatures (10°C, 15°C, 20°C, 25°C, 30°C, and 35°C). Results were summarized as a quadratic equation relating light and temperature to growth and indicate that optimal growth occurred at 26°C and 227 µM m-2)s-1) of light. Thus, N. spongiaeforme grows well at water temperatures and light levels similar to those measured in rice fields during the critical 30 days following initial flooding of the field. [ABSTRACT FROM AUTHOR]

The taxonomic composition and biomass of phytoplankton in the San Joaquin River, California, were examined in relation to water depth, flow regime, and water chemistry. Without substantial tributary inflow, maintenance demands exceeded algal production during summer and autumn in this eutrophic, `lowland type' river due to light-limiting conditions for algal growth. Streamflow from tributaries that drain the Sierra Nevada contributed to a substantial net gain in algal production during the spring and summer by increasing water transparency and the extent of turbulence. Abundances of the major taxa (centric diatoms, pennate diatoms and chlorophytes) indicated differing responses to the longitudinal variation in water depth and flow regime, with the areal extent of pools and other geomorphic features that influence time-for-development being a major contributing factor to the selection of species. Tychoplanktonic species were most abundant upstream and in tributaries that drain the San Joaquin Valley. Seasonally-varying factors such as water temperature that influence algal growth rates also contributed significantly to the selection of species. Nutrient limitation appears not to be a primary constraint on species selection in the phytoplankton of this river. [ABSTRACT FROM AUTHOR]

1. The taxonomic composition and biomass of the phytoplankton and the taxonomic composition of the phytobenthos of the San Joaquin River and its major tributaries were examined in relation to water chemistry, habitat and flow regime. Agricultural drainage and subsurface flow contribute to a complex gradient of salinity and nutrients in this eutrophic, ‘lowland type’ river. 2. Because of light-limiting conditions for growth, maintenance demands of the algae exceed production during summer and autumn in the San Joaquin River where there is no inflow from tributaries. In contrast to substantial gains in concentration of inorganic nitrogen and soluble reactive phosphorus during the summer of normal-flow years, net losses of algal biomass (2–4 μg L-1 day-1 chlorophyll a) occurred in a mid-river segment with no significant tributary inflow. However, downstream of a large tributary draining the Sierra Nevada, a substantial net gain in algal biomass (6–11 μg L-1 day-1) occurred in the summer, but not in the spring (loss of 1–6 μg L-1 day-1) or autumn (loss of 2–5 μg L-1 day-1). 3. The phytoplankton was dominated in summer by ‘r-selected’ centric diatoms (Thalassiosirales), species both tolerant of variable salinity and widely distributed in the San Joaquin River. Pennate diatoms were proportionally more abundant (in biomass) in the winter, spring and autumn. Abundant taxa included the diatoms Cyclotella meneghiniana, Skeletonema cf. potamos, Cyclostephanos invisitatus, Thalassiosira weissflogii, Nitzschia acicularis, N. palea and N. reversa, and the chlorophytes Chlamydomonas sp. and Scenesdesmus quadricauda. Patterns in the abundance of species indicated that assembly of the phytoplankton is limited more by light and flow regime than by nutrient supply. 4. The phytobenthos was dominated by larger, more... [ABSTRACT FROM AUTHOR]

California water-seeded rice is challenged with the rapid growth of nuisance algae at the beginning of the season. Rice seedlings entangled in the algal mat may not be established, causing empty rice patches in the field. Two separate studies were conducted to (1) evaluate the effect of nutrients (nitrogen and phosphorous) on algae growth, and (2) test various chemical options to control algae. Both studies utilized 19 L buckets inoculated with algae collected from a rice field. In the nutrient evaluation study, 36 nutrient treatments obtained from a combination of nitrogen (0, 60, 120, 180, 240 and 300 kg ha−1) and phosphorous (0, 20, 40, 60, 80 and 100 kg ha−1) rates were applied into the buckets, while eight chemicals with potential for algae control (two Protox inhibitor herbicides, four copper-based compounds, hydrogen peroxide, Zinc sulfate) were tested in the second experiment. In addition, a yeast extract-based surfactant (AMP activator) was tested in combination with a chelated copper formulation (Algimycin) and hydrogen peroxide. The studies had a completely randomized design with three replicates and each study was repeated two times. The result from the nutrient evaluation study showed that nitrogen and phosphorus can independently cause change in algae growth as reflected in the fresh and dry biomass. Moreover, low rates of either nitrogen or phosphorus resulted in a rapid increase in algae biomass and water chlorophyll a content, whereas the growth of algae declined at higher rates of applied fertilizer. Among tested chemicals in the second experiment, the chelated formulation of copper (Algimycin PWF) controlled algae (85%) better than the ethanolamine formulations [Cutrine-Ultra (70%) and Cutrine-Plus (52%)] and elemental copper (crystalline copper sulfate) (75%). Protox herbicides (oxyfluorfen and oxadiazon) were able to control algae by up to 70%. Hydrogen peroxide controlled algae by 50% and its efficacy dropped dramatically five days after treatment (DAT). Zinc sulfate was only effective at 1 DAT and algae recovered rapidly after that. Combining fertilizer management practices with chemical options will enable us toward an integrative approach for early algal bloom in the rice cropping system. [ABSTRACT FROM AUTHOR]

A routine sampling technique has been developed using artificial Styrofoam substrate to estimate benthic algal productivity in the littoral zone of lakes. Estimation of maximum carbon fixed in Lake Tahoe ranged from 11.1 mg C·m[SUP-2]·day[SUP-1] at 0.5 m to 17.1 mg C·m[SUP-2]·day[SUP-1] at 1.0 m. Estimates were made for communities composed of both diatom and green algal populations in water between 0.5 and 3.0 m. Maximum productivity occurred between 1-2 m. The technique developed can give comparable estimates of productivity if adequate replication is undertaken to decrease problems associated with periphytic heterogeneity. [ABSTRACT FROM AUTHOR]