Ecological studies ofGracilaria asiatica andGracilaria lemaneiformis in Zhanshan Bay,Qingdao

Natural populations ofG. asiatica Zhang & Xia andG. lemaneiformis (Bory) Weber van Bosse were studied during 1984 and 1986 in Zhanshan Bay, Qingdao (36°4'N, 120° 21'E). Rapid growth (length, weight) of these plants occurred between mid-May and late June (water temperatures, 15–20°C). The major epiphyte ofG. asiatica wasEnteromorpha linza, whilePunctaria latifolia was the major epiphyte ofG. lemaneiformis. Epiphytism declined throughout early summer, and epiphytes were rare after mid-July (1984); they did not reappear in late summer, although macrophyte growth declined abruptly after early July. Populations ofG. asiatica varied during late spring-early summer between adjacent sandy and rocky portions of the intertidal zone; plants at the sandy site were larger and epiphyte-free. Amphipod densities were low on both species ofGracilaria, but the most abundant species wereAmpithoe lacertosa, Caprella equilibra, C. krøyeri, C. scauraandPontogeneia rostrata. Additional information on general community structure is provided for theG. asiatica zone.     

SPATIAL PATTERNS OF SUPPORT FOR A NUCLEAR WEAPONS FREEZE*

Support for a Freeze on nuclear weapons is greatest in the East with pockets of support in the Middle West and Pacific Coast States. Factors influencing the spatial pattern are Walker's innovativeness rankings, the number of peace/Freeze activist groups and the pattern of defense employment.     

A novel charge-transfer polymer for separating hydrocarbon fractions of crude oils

Hydrocarbon fractions in crude oil were separated by a new charge-transfer polymer in place of silver ions in Argentation TLC. The charge-transfer plates are cheaper than their silver nitrate equivalents, do not discolour, and store well. The polymer/silica gel mix can be re-used.     

Correspondence analysis of water quality data: Implications for fauna deaths at Stillwater Lakes, Nevada

Over the last 2 years, more than seven million fish and 16,000 birds have died from drought-induced disease and suspected poisoning at Stillwater Lakes, Nevada. Correspondence analysis of water samples taken in June and September 1986, from lakes and reservoirs near Stillwater Lakes and four background lakes/reservoirs (not associated with fauna disease and death), is attempted to investigate the correlation among sites associated with fauna deaths. This analysis identifies high correlation between some Stillwater Lakes sites and boron. A correlation between boron and arsenic is also identified. Leaching and transport of toxins to the Stillwater Lakes system is one hypothesis to explain the wildlife deaths. Other hypotheses include the direct introduction of toxins by groundwater associated with geothermal activity. A natural cause for the wildlife deaths is also suggested, a cause not associated with the introduction of toxins.     

Numerical simulation of the circulation within the Perth Submarine Canyon,Western Australia

Surface and sub-surface currents along the ocean boundary of Western Australia were simulated using Regional Ocean Modelling System (ROMS) to examine the circulation within the Perth Canyon. Two major current systems influenced the circulation within the canyon: (1) The Leeuwin current interacted weakly with the canyon as the majority of the canyon was below the depth of the Leeuwin current and (2) Leeuwin undercurrent interacted strongly with the canyon, forming eddies within the canyon at depths of 400–800 m. The results indicated that within the canyon, the current patterns changed continuously although there were some repeated patterns. Recurrent eddies produced regions where upwelling or downwelling dominated during the model runs. Deep upwelling was stronger within the canyon than elsewhere on the shelf, but vertical transport in the upper ocean was strong everywhere when wind forcing was applied. Upwelling alone appeared to be insufficient to transport nutrients to the euphotic zone because the canyon rims were deep. Increased upwelling, combined with entrapment within eddies and strong upwelling-favourable winds, which could assist mixing, may account for the high productivity attributed to the canyon. The Leeuwin current is otherwise a strong barrier to the upwelling of nutrients.     

Climatic Trends and Temporal Patterns of Phytoplankton Composition, Abundance, and Succession in the Indian River Lagoon, Florida, USA

This paper describes the results of 10 years of water quality monitoring in the Indian River Lagoon Florida, with special emphasis on the relationships between trends in climatic conditions and the distribution, composition, and abundance of the phytoplankton community. The Indian River Lagoon, which spans 220 km of Florida’s east coast, is a region of particular concern because of the rapid rate of human development throughout the region and the hydrologically restricted character of the lagoon, which heightens the potential for algal bloom. Water sampling was carried out on a monthly to twice-monthly basis at six sites located in the northern and central lagoon. The 10-year study included both extended periods of below and above average rainfall. A number of ecologically distinct regions exist within the lagoon, which differ considerably in water exchange properties and watershed inputs. The northern lagoon is characterized by longer water residence times, lower phosphorus concentrations, higher nitrogen concentrations, and more stable salinity conditions than the central lagoon. Mean phytoplankton biovolumes were substantially higher at the sites in the northern lagoon than at the sites in the central lagoon, and algal blooms were more common and intense in the former region. Inter-annual patterns of phytoplankton biovolume were also different in the northern and central lagoon. In the northern lagoon, phytoplankton biovolumes were lowest during the drought period, from the autumn of 1998 to the spring of 2001. By contrast, algal bloom events in the central lagoon were not only less frequent but were not tied to periods of high rainfall. The most widespread and common bloom formers were the potentially toxic dinoflagellate Pyrodinium bahamense var. bahamense and two centric diatoms, Dactyliosolen fragilissimus and Cerataulina pelagica. Many of the biovolume peaks observed over the study period were attributable to these three species. The results of time series modeling of phytoplankton dynamics further highlighted the disparities between the two regions of the lagoon in terms of the suite of parameters that best predict the observed trends in the biomass of phytoplankton. Overall, the outcome of this initial modeling effort in the Indian River Lagoon suggests that time series approaches can help define the factors that influence phytoplankton dynamics.