Diatom distribution in surface sediments from Chinese inshore waters and the relationship to modern environmental variables

AbstractThe epifaunal assemblage was evaluated at three different depths (5, 15 and 25 m) in the inshore waters of Pazhayar, Parangipettai and Cuddalore apart from 5 m depth near SIPCOT covering totally 10 stations (11°21′ N to 11°42′ N; 79°46′49″ E to 79°52′34″ E) in the southeast coast of India, Bay of Bengal. The occurrence of as many as 112 species belonging to 6 groups was recorded. Among these, gastropods constituted the largest component (42.85%) with 48 species. Bivalves came next with the percentage contribution of 24.10% with 27 species. Crustaceans and polychaetes contributed with 16.96% (19 species) and 6.25% (7 species), respectively. Others contributed with 9.82% (11 species). The maximum number of species was recorded in Cuddalore transect (65 species) and the minimum in SIPCOT (20 species). The maximum abundance was recorded in SIPCOT (1363 ind./haul) but the diversity was found to be lower here than in the other stations. The bivalve, Scapharca inaequivalvis was abundant only in this station whereas the large sized polychaetes, Epidiopatra hupferiana monroi and Sternaspis scutata were found only in the Pazhayar transect during all the seasons. Multivariate analyses were done to define assemblages. The total number of species estimated by various extrapolators varied from 112 species to 169.73 species. The cluster analysis revealed the gradual change in species composition with increase in depth. In the principal coordinate analysis (PCO) the first two axes explained 49.8% of the total variability in the case of biota and 98.3% of the total variability in the case of environmental variables. The distance based linear model (DISTLM) was used to find out the relationship between the abundance of epifauna and environmental variables. Depth explained about 23.7% of the variability while temperature and pH explained 17.5 and 10.6%, respectively. The best solution suggested all the nine environmental variables to combinedly explain about 92.49% of the total variability

Download Full-text

A new diatom training set for the reconstruction of past water pH in the Tatra Mountain lakes

Journal of Paleolimnology ◽

10.1007/s10933-021-00182-0 ◽

2021 ◽

Author(s):

Elwira Sienkiewicz ◽

Michał Gąsiorowski ◽

Ladislav Hamerlík ◽

Peter Bitušík ◽

Joanna Stańczak

Keyword(s):

Surface Sediments ◽

Tatra Mountains ◽

Training Set ◽

Statistical Parameters ◽

The Past ◽

Water Ph ◽

Inferred Ph ◽

The 1960S ◽

The Tatra Mountains ◽

The Relationship

AbstractLakes located in the Polish and Slovak parts of the Tatra Mountains were included in the Tatra diatom database (POL_SLOV training set). The relationship between the diatoms and the water chemistry in the surface sediments of 33 lakes was the basis for the statistical and numerical techniques for quantitative pH reconstruction. The reconstruction of the past water pH was performed using the alpine (AL:PE) and POL_SLOV training sets to compare the reliability of the databases for the Tatra lakes. The results showed that the POL_SLOV training set had better statistical parameters (R2 higher by 0.16, RMSE and max. bias lower by 0.2 and 0.36, respectively) compared to the AL:PE training set. The better performance of the POL_SLOV training set is particularly visible in the case of Przedni Staw Polski where the curve of the inferred water pH shows an opposite trend for the period from the 1960s to 1990 compared to that based on the AL:PE dataset. The reliability of the inferred pH was confirmed by the comparison with current instrumental measurements.

Download Full-text

A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production

ICES Journal of Marine Science ◽

10.1093/icesjms/fsr002 ◽

2011 ◽

Vol 68 (3) ◽

pp. 528-536 ◽

Cited By ~ 12

Author(s):

Miguel Bernal ◽

Yorgos Stratoudakis ◽

Simon Wood ◽

Leire Ibaibarriaga ◽

Luis Valdés ◽

...

Keyword(s):

Temporal Variability ◽

Environmental Variables ◽

Egg Production ◽

Stock Assessment ◽

Production Model ◽

Estimation Methods ◽

Statistical Framework ◽

Spatio Temporal ◽

The Relationship ◽

Made In

Abstract Bernal, M., Stratoudakis, Y., Wood, S., Ibaibarriaga, L., Uriarte, A., Valdés, L., and Borchers, D. 2011. A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production. – ICES Journal of Marine Science, 68: . A spatially and environmentally explicit egg production model is developed to accommodate a number of assumptions about the relationship between egg production and mortality and associated environmental variables. The general model was tested under different assumptions for Atlanto-Iberian sardine. It provides a flexible estimator of egg production, in which a range of assumptions and hypotheses can be tested in a structured manner within a well-defined statistical framework. Application of the model to Atlanto-Iberian sardine increased the precision of the egg production time-series, and allowed improvements to be made in understanding the spatio-temporal variability in egg production, as well as implications for ecology and stock assessment.

Download Full-text

Consistency of patterns between laboratory experiments and field collected fish in otolith chemistry: an example and applications for salinity reconstructions

Marine and Freshwater Research ◽

10.1071/mf04146 ◽

2005 ◽

Vol 56 (5) ◽

pp. 609 ◽

Cited By ~ 71

Author(s):

T. S. Elsdon ◽

B. M. Gillanders

Keyword(s):

Environmental Variables ◽

Laboratory Experiments ◽

Juvenile Fish ◽

Otolith Chemistry ◽

Ambient Water ◽

Elemental Concentrations ◽

Adequate Knowledge ◽

Black Bream ◽

Environmental Histories ◽

The Relationship

Elemental concentrations within fish otoliths can track movements and migrations of fish through gradients of environmental variables. Tracking the movements of fish relies on establishing links between environmental variables and otolith chemistry, with links commonly made using laboratory experiments that rear juvenile fish. However, laboratory experiments done on juvenile fish may not accurately reflect changes in wild fish, particularly adults. We tested the hypotheses that: (1) the relationship between ambient (water) and otolith chemistry is similar between laboratory-reared black bream (Acanthopagrus butcheri) and wild black bream; and (2) ontogeny does not influence otolith chemistry. Field-collected and laboratory-reared fish showed similar effects of ambient strontium : calcium (Sr : Ca) on otolith Sr : Ca concentrations. However, ambient and otolith barium : calcium concentrations (Ba : Ca) differed slightly between laboratory-reared and field-collected fish. Importantly, fish reared in stable environmental variables showed no influence of ontogeny on Sr : Ca or Ba : Ca concentrations. Natural distributions of ambient Sr : Ca showed no clear relationship to salinity, yet, ambient Ba : Ca was inversely related to salinity. The distribution of ambient Sr : Ca and Ba : Ca in estuaries inhabited by black bream, suggest that these elements can answer different questions regarding environmental histories of fish. Reconstructing salinity histories of black bream using otolith Ba : Ca concentrations seems plausible, if adequate knowledge of Ba : Ca gradients within estuaries is obtained.

Download Full-text

Monitoring studies should consider temporal variability to reveal relations between cyanobacterial abundance and environmental variables

Anais da Academia Brasileira de Ciências ◽

10.1590/0001-3765201520140416 ◽

2015 ◽

Vol 87 (3) ◽

pp. 1717-1726 ◽

Cited By ~ 3

Author(s):

JULIANA WOJCIECHOWSKI ◽

ANDRÉ A. PADIAL

Keyword(s):

Temporal Variability ◽

Environmental Variables ◽

Environmental Changes ◽

Environmental Variability ◽

Time Lag ◽

Cyanobacteria Blooms ◽

Environment Variables ◽

Sampling Points ◽

The Relationship

One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs, and data from an intensive monitoring in one of these reservoirs. Poor correlations were obtained when correlating data simultaneously sampled. In fact, the 'highly recurrent' role of phosphorus in cyanobacteria blooms is not properly observed in all sampling periods. On the other hand, the strongest correlation values for the total phosphorus x cyanobacteria relationship were observed when we used the variation of sampling points. We have also shown that environment variables better explain cyanobacteria when a time lag is considered. We conclude that, in cyanobacteria monitoring, the best approach to reveal determinants of cyanobacteria blooms is to consider environmental variability.

Download Full-text