Mallomonadacean (Chrysophyceae) assemblages and their relationships with limnological characteristics in 38 Adirondack (New York) lakes

1984 ◽  
Vol 62 (5) ◽  
pp. 911-923 ◽  
Author(s):  
John P. Smol ◽  
Donald F. Charles ◽  
Donald R. Whitehead

The siliceous scales of 30 mallomonadacean taxa were identified and counted from the surficial sediments of 38 Adirondack lakes. The scales were usually abundant and were always well preserved. The Adirondack flora is typical of acidic to circumneutral oligotrophic lakes. Common taxa include Mallomonas acaroides, M. caudata, M. crassisquama, M. hamata, M. pseudocoronata, M. punctifera, Synura echinulata, S. petersenii, S. sphagnicola, S. spinosa, and Chrysosphaerella longispina. The abundance of certain species (e.g., Mallomonas hindonii, M. hamata) appears to be a reliable indication of acidic waters. Reciprocal averaging (RA) ordination was used to determine if distribution of the mallomonadacean assemblages corresponded with major environmental gradients. Correlations between the first RA axis scores and lakewater pH (r2 = 0.63) and related factors (log10 alkalinity, r2 = 0.66; pCa, r2 = 0.39; pMg, r2 = 0.43) were strongest. Relationships were weaker with average depth, summer epilimnion temperature, elevation, NO3, and total Al, and were not statistically significant with conductivity, color, Secchi disc transparency, total P, chlorophyll a, SO4, and Si. Cluster analysis grouped both lakes and taxa into categories best explained by their pH-related characteristics. Analysis of surficial sediment from lakes with known limnological characteristics is a useful approach for the study of the ecology and taxonomy of the Mallomonadaceae. Our data demonstrate that mallomonadacean distributions reflect lake conditions and, therefore, are potentially useful indicators in limnological and paleolimnological studies.


1988 ◽  
Vol 66 (7) ◽  
pp. 1449-1460 ◽  
Author(s):  
Stephen T. Jackson ◽  
Donald F. Charles

A study of aquatic vegetation of 31 small, dilute, and unproductive lakes in the Adirondack Mountains of New York shows that macrophyte species composition is primarily related to variation in pH and associated factors. Among the lakes, surface water pH ranged from 4.5 to 7.8; conductivity ranged from 11.9 to 58.7 μS/cm. Relationships between aquatic vegetation and environmental factors were studied using detrended correspondence analysis (DCA). Submersed and floating-leaved taxa were analyzed separately from emergent taxa. Correlations between DCA axis 1 and pH-related factors (pH, alkalinity, Ca, Mg, Na, Al, conductivity, elevation) were strong for both submersed plus floating-leaved and emergent taxa. No significant correlations were found with water color, transparency, or trophic status indicators (total P and chlorophyll a). Between-lake variation in composition of aquatic vegetation in Adirondack lakes follows a pH "complex-gradient." Influences of elevation, morphometry, and substrate are secondary. Our results indicate that acidification of softwater lakes could be accompanied by significant changes in aquatic macrophyte assemblages.



1988 ◽  
Vol 66 (7) ◽  
pp. 1391-1403 ◽  
Author(s):  
Peter A. Siver

Thirty-four scaled chrysophyte taxa are described from 17 Adirondack lakes located in either Hamilton or Franklin counties. Ten taxa, Synura sphagnicola, Syn. echinulata, Syn. petersenii, Mallomonas acaroides var. muskokana, M. hamata, M. caudata, M. crassisquama, M. galeiformis, Spiniferomonas trioralis, and Chrysosphaerella longispina, were found in more than 40% of the study lakes. Mallomonas acaroides var. muskokana, M. hamata, Syn. sphagnicola, Syn. echinulata, and Spiniferomonas coronacircumspina were common and important components of the phytoplankton floras in lakes with a pH < 5.4; however, M. hamata and Sp. coronacircumspina were noticeably absent from bog lakes. Synura sphagnicola and Syn. echinulata were as common in samples with a pH between 5.4 and 7 as they were below pH 5.4. Mallomonas crassisquama, M. caudata, M. pseudocoronata, and Synura spinosa were found in a significantly greater percentage of samples from circumneutral lakes and were lacking from waters with a pH < 5.4. Differences in species distributions between Hamilton County (higher mean pH) and Franklin County lakes further supported the observed pH ranges of the common taxa. Similarities and differences are made with a study of Smol et al. (Can. J. Bot. 62: 911–923), who described the distribution of scaled chrysophytes from the surface sediments of Adirondack lakes.



1984 ◽  
Vol 22 (1) ◽  
pp. 72-76 ◽  
Author(s):  
Kenton M. Stewart ◽  
Bruce E. Brockett
Keyword(s):  
New York ◽  


1988 ◽  
Vol 66 (4) ◽  
pp. 804-810 ◽  
Author(s):  
Karl E. Parker

The effects of lake acidification on common loon reproduction were studied on a total of 24 Adirondack lakes from May through August in 1983 and 1984. The lakes ranged in size from 10.5 to 179 ha; pH ranged from 4.65 to 6.77 and alkalinity from −66 to 111 μequiv./L. Although loons nesting on small, low-pH lakes had a high fledging rate, possibly because of reduced disturbance or predation, no significant relationship (P > 0.10) was found between lake acidity status and loon reproductive success. No chick mortality could be attributed to lake acidification, but chicks on low-pH lakes were generally fed prey much smaller or much larger than those normally preferred. A pair nesting on a fishless lake fed aquatic insects to their constantly begging chick, spending two to four times longer feeding the chick compared with loons on lakes with fish. This pair, alternating absences, flew to another lake to feed, and on three occasions returned to the nesting lake carrying a fish. Loons on the low-pH study lakes apparently adapted, at least in the short term, to food resource depletion associated with acidification. Despite this, acidification creates potentially severe feeding problems for chicks by reducing prey diversity and quantity.



2011 ◽  
Vol 12 (6_suppl_1) ◽  
pp. 63S-72S ◽  
Author(s):  
Marielena Lara ◽  
Tyra Bryant-Stephens ◽  
Maureen Damitz ◽  
Sally Findley ◽  
Jesús González Gavillán ◽  
...  

The Merck Childhood Asthma Network (MCAN) initiative selected five sites (New York City, Puerto Rico, Chicago, Los Angeles, and Philadelphia) to engage in translational research to adapt evidence-based interventions (EBIs) to improve childhood asthma outcomes. The authors summarize the sites’ experience by describing criteria defining the fidelity of translation, community contextual factors serving as barriers or enablers to fidelity, types of adaptation conducted, and strategies used to balance contextual factors and fidelity in developing a “best fit” for EBIs in the community. A conceptual model captures important structural and process-related factors and helps frame lessons learned. Site implementers and intervention developers reached consensus on qualitative rankings of the levels of fidelity of implementation for each of the EBI core components: low fidelity, adaptation (major vs. minor), or high fidelity. MCAN sites were successful in adapting core EBI components based on their understanding of structural and other contextual barriers and enhancers in their communities. Although the sites varied regarding both the EBI components they implemented and their respective levels of fidelity, all sites observed improvement in asthma outcomes. Our collective experiences of adapting and implementing asthma EBIs highlight many of the factors affecting translation of evidenced-based approaches to chronic disease management in real community settings.



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