Geographic distribution of dinoflagellate cysts in surface sediments

Dinoflagellate cysts are useful for reconstructing upper water conditions. For adequate reconstructions detailed information is required about the relationship between modern day environmental conditions and the geographic distribution of cysts in sediments. This Atlas summarises the modern global distribution of 71 organicwalled dinoflagellate cyst species. The synthesis is based on the integration of literature sources together with data of 2405 globally distributed surface sediment samples that have been preparedwith a comparable methodology and taxonomy. The distribution patterns of individual cyst species are being comparedwith environmental factors that are knownto influence dinoflagellate growth, gamete production, encystment, excystment and preservation of their organic-walled cysts: surface water temperature, salinity, nitrate, phosphate, chlorophyll-a concentrations and bottom water oxygen concentrations. Graphs are provided for every species depicting the relationship between seasonal and annual variations of these parameters and the relative abundance of the species. Results have been compared with previously published records; an overview of the ecological significance as well as information about the seasonal production of each individual species is presented. The relationship between the cyst distribution and variation in the aforementioned environmental parameters was analysed by performing a canonical correspondence analysis. All tested variables showed a positive relationship on the 99% confidence level. Sea-surface temperature represents the parameter corresponding to the largest amount of variance within the dataset (40%) followed by nitrate, salinity, phosphate and bottom-water oxygen concentration, which correspond to 34%, 33%, 25% and 24% of the variance, respectively. Characterisations of selected environments as well as a discussion about how these factors could have influenced the final cyst yield in sediments are included.

(Table 2) Dinoflagellate cysts in surface sediment samples of METEOR cruises M20/2, M23/1, M34/2 and M34/2

The organic walled cyst content of 41 surface sediment samples from the south-eastern South Atlantic Ocean have been studied to create a dataset that can be used for palaeoceanographic reconstructions. In order to obtain insight into which environmental factors influence the distribution of individual cyst species, the cyst associations have been compared with oceanographic characteristics of the overlying water masses, i.e. temperature, salinity, density and stratification gradients. The associations and relationships have been established by visual examination of the dataset and the multivariate ordination techniques, Detrended Correspondence Analysis and Canonical Correspondence Analysis. Special attention has been given to the factors of transport and preservation of the cysts. Five associations have been recognised as being characteristic of (1) areas influenced by coastal upwelling and/or river outflow, (2) open ocean, (3) Agulhas Current and southern Benguela Current, (4) Benguela Current and (5) Walvis Bay, shelf break area. The factors dominant in influencing either directly or indirectly the cyst distributions appear to be the stratification in the upper 50 m of the water column, nutrient concentration and seasonality. Variations in sea surface temperatures and salinities have only minor effect on cyst distribution.

Benthic fauna of an offshore borrow area in Broward County, Florida /

Benthic fauna from two stations within a 5-year-old borrow area and two control stations off Hillsboro Beach (Broward County), Florida, were sampled quarterly from June 1977 to March 1978 to evaluate the long-term impact of offshore dredging. Generally enhanced productivities occurred within the borrow area, although there was much seasonal variation among stations. Species diversities were usually higher at the borrow stations than at the control stations. The single exception was due to a high concentration of the bivalve E. nitens at one of the control stations in June. Although faunal similarity analysis revealed a qualitative change in the fauna of the borrow area, this change is not considered detrimental. Conspicuous patterns of heterogeneous faunal distributions were evident in this study, particularly for the bivalve E. nitens. No lasting detrimental effects, in terms of numbers of species, faunal densities, or species diversity, resulted from the dredging operation. (Author).

Draft environmental impact statement, Fence Lake project.

"BLM-NM-PT-90-010-7122"--P. [2] of cover.

New approaches to the preservation of contaminants in water samples /

Jan. 1979.

Handbook for sampling and sample preservation of water and wastewater.

Mode of access: Internet.

Impact of air pollution on the consumption of medical services : cost of hospitalization in the Portland metropolitan area /

Mode of access: Internet.

Baker resource management plan : draft : environmental impact statement /

"BLM-OR-ES-86-011-1792"--P. [4] of cover.

Transit requirements for achieving large reductions in Los Angeles area automobile travel /

Includes appendices.

BART in the San Francisco Bay Area - the final report of the BART Impact Program.

Transportation Department, Washington, D.C.

Environmental impacts of BART: interpretive summary of the final report.

Transportation Department, Washington, D.C.

Hydrology of the White Tail Butte area, northern Campbell County, Wyoming /

Shipping list no.: 87-323-P.

Cuál es el problema con el aire? : alerta especial para personas con asma y otros problemas respiratorios en el area metropolitana de Chicago, el noroeste de Indiana y el sudeste de Wisconsin.

Mode of access: Internet.

Public health assessment, 150 Fulton Avenue/Garden City Park industrial area, Garden City Park, Nassau County, New York /

"July 8, 2002; CERCLIS No. NYD000110247."

Public health assessment, Old Roosevelt Field Contaminated Groundwater Area, town of Hempstead, Nassau County, New York /

"CERCLIS number NYSFN0204234."