Paula C. Furey

New Algal Species Records for Great Smoky Mountains National Park, with an Annotated Checklist of all Reported Algal Taxa for The Park

Abstract Great Smoky Mountains National Park, which straddles the Tennessee–North Carolina state-line is a biologically diverse region which has recently become the site of an All Taxon Biodiversity Inventory, an effort to chronicle species diversity by documenting all species in all phyla present within park boundaries. As a result of studies within the last two years, we have added 415 new algal taxa records. With records reported in 2004, we now have documented a total of 1000 taxa in the park. This paper summarizes all algal species found to date.

Midges, Cladophora, and epiphytes: shifting interactions through succession

Abstract.  Midge larvae (Pseudochironomus richardsoni Malloch) in the South Fork Eel River, California, weave retreats in mats of Cladophora glomerata (L.) Kütz. and graze on its algal epiphytes. Densities of these midges and their effects on Cladophora vary over time (seasonally, over the course of succession, and interannually) and space (down the drainage network). New Cladophora growth is green, turns yellow with early colonization by a monolayer of Cocconeis, and rusty-red as it becomes heavily epiphytized by a multistory layer of Epithemia spp. (Rhopalodiaceae), diatoms that contain N-fixing endosymbiotic cyanobacteria. To determine how midges influence epiphyte assemblage structure, we incubated Cladophora in early (green [G]), mid (yellow [Y]), and late (rusty-red [R]) stages of succession with and without midges and assessed changes in epiphyte density and composition. Midge effects on epiphyte composition and density (as measured by % cover on Cladophora filaments) varied with stage of succession and proximity to the ends of midge retreats. Local increases in retreat-associated cyanobacteria occurred in Y and R stages. Percent cover of Cocconeis increased on Y filaments >2 cm from midge retreats (ambient) indicating indirect midge effects (e.g., fertilization). Midges were less effective grazers on adnate Cocconeis cells than on loosely attached Epithemia and often ingested Cladophora in the process of grazing or retreat building, especially in G and Y stages. In contrast, midges that grazed on R Cladophora primarily consumed diatoms in the Rhopalodiaceae. Midge survival and retreat quality were lower in G than in Y or R stages, where retreats were longer and denser. Shifts in epiphyte composition and % cover caused by midge–algae interactions at small scales (µm–m) could affect ecologically significant processes, such as N-fixation and foodweb interactions at larger reach and watershed scales.

Diatom Biodiversity and Distribution on Wetwalls in Great Smoky Mountains National Park

Abstract Diatoms and other algae were collected and identified from subaerial habitats (wetwalls) in Great Smoky Mountains National Park as part of a larger biodiversity survey of the Park. Algal collections were made across a range of moisture gradients and bedrock mineralogies with pH ranging from 3.8 to 7.7. None of the communities collected were entirely submerged in water, but were often associated with moist bryophytes, cyanobacterial mats, and dripping groundwater seeps. Some of the collections were from cliff faces wetted only periodically. To date, 41 diatom genera and over 223 species have been identified from these habitats. Several of these genera are widely distributed across aquatic habitats; however, several of the genera are “subaerial specialists” and possess morphological features such as reduced size, reduced external openings in the cell wall, or additional external siliceous membranes that allow them to survive in relatively dry habitats. Widely distributed species with high fidelity to subaerial habitats occur in the genera Achnanthes, Cymbopleura, Decussata, Diadesmis, Luticola, Melosira, Microcostatus, Nupela, Psammothidium, and Orthoseira. Many of the species constitute new Park records, national records, or are new to science.

The perils of unpalatable periphyton: Didymosphenia and other mucilaginous stalked diatoms as food for tadpoles

Proliferations of Didymosphenia geminata are becoming prevalent in rivers around the globe. In the Sierra Nevada of California, Didymosphenia and other taxa that produce mucopolysaccharide stalks (e.g., Gomphoneis, Cymbella) can dominate benthic environments, particularly in the altered hydrologic and thermal regimes downstream of dams. We compared the prevalence of stalked diatoms in paired reaches, one free-flowing and the other regulated, within two Sierran river systems, the American and Feather Rivers. In the regulated reaches, short-term power generation caused daily flow fluctuations and periphyton biovolume was dominated by either Didymosphenia (where hypolimnetic releases created cool summer temperatures) or other stalked diatom taxa (where temperatures were warm). Periphyton assemblages from the unregulated sites were significantly different from the regulated reaches based on biovolume, with Gomphonema being the genus at unregulated sites contributing to the dissimilarities after accounting for the stalked genera from the regulated reaches. We evaluated the consequences of mucopolysaccharides for a large-bodied grazer, tadpoles of the foothill yellow-legged frog (Rana boylii), in a factorial experiment manipulating diet and thermal regime. At 16.6°C mean daily temperature, tadpoles lost weight (72 h relative change of−16.1±7.2%) when grazing on periphyton from a Didymosphenia-dominated site. At 19.9°C (similar to unregulated river conditions), tadpoles grazed Didymosphenia at a rate similar to tadpoles consuming higher protein control periphyton, but the former tadpoles did not grow (relative change of 4.3±5.4% vs 30.7±3.4% for control periphyton). When tadpoles were fed periphyton dominated by mucilaginous stalked diatoms other than Didymosphenia, tadpole weight loss was 21.0±9.2% (cool) and 16.6±5.6% (warm). The results illustrate that hydrologically or thermally mediated shifts in periphyton composition can have significant implications for the energy transferred to grazers.

TERATOLOGY IN EUNOTIA TAXA IN THE GREAT SMOKY MOUNTAINS NATIONAL PARK AND DESCRIPTION OF EUNOTIA MACROGLOSSA SP. NOV.

High altitude springs and headwater streams directly interact with atmospheric deposition and as a result may be useful first response bioindicators of changes in acid precipitation, i.e. from increased acid rain or mitigation efforts. We examined the diatom assemblages associated with bryophytes collected from high elevation springs and streams in the Great Smoky Mountains National Park, U.S.A. in 2005 and 2007. The high elevation areas were dominated by Eunotia taxa, primarily E. subarcuatoides Alles, Nörpel et Lange-Bert., and secondarily by E. exigua (Bréb. ex Kütz.) Rabh., E. muscicola var. tridentula Nörpel et Lange-Bert., and E. macroglossa sp. nov. The presence of valve malformations in four of the high elevation springs and two streams suggest that acid precipitation in the park may be interacting with local bedrock geology to release metals toxic to algal communities, especially under the low pH conditions of these high elevation areas. Sites with the greatest number of deformities showed higher levels of Al, Ba, and Mn relative to other sites. Internal and external diatom morphology of normal and abnormal E. subarcuatoides valves were explored and demonstrated the presence of valve aberrations across all size ranges, including shape distortions and unusual raphe development. No difference in mean valve length or size range was present between normal and abnormal valves. However, more data are necessary before any clear linkages between diatom deformities, metals, geology, and acid precipitation can be unequivocally established.

Frankophila wayqechae sp. nov., a new aerophilic diatom species from the Peruvian Andes, South America

The genus Frankophila Lange-Bertalot is characterized as a small chain-forming diatom with frustules held together by interdigitating marginal spines. Both valves of the species in this genus possess a short raphe at the distal ends. Five species of Frankophila have been recognized to date with most being described from subaerial habitats. Exploration of moist, vertical, rock walls in the Peruvian Andes led to the discovery of a new Frankophila species, F. wayqechae Furey, Mayama, Lowe & Catenazzi, sp. nov., which is described from a high altitude (3506 m above sea level), moist, vertical wet wall located in the transition zone between the grasslands and cloud forests growing on the eastern slope of the Andes in Manu National Park. Light and scanning electron micrographs of internal and external morphology and ultrastructure are presented along with basic ecological information. This new taxon is compared with species in the genus Hygropetra Krammer & Lange-Bertalot, primarily H. gelasina Mayama & Idei, and phylogenetic relationships inferred from valve and chloroplast features are discussed. The triseriate striae and depressions in the valve axial area of F. wayqechae differentiate it from other currently described Frankophila species. The velum at the inner opening of the areolae and triseriate striae of F. wayqechae are similar to the genus Hygropetra which suggests a close relationship between these taxa. Frankophila wayqechae has a single chloroplast per cell that expands in the large area beneath one valve without lobes along a sternum. The nature of the chloroplast, combined with the pattern of areolation in the striae and internal areola occlusion by a hymen also suggests F. wayqechae may be a close relative of Planothidium Round & Bukhtiyarova. Frankophila wayqechae appears to be restricted to high elevation areas in the Peruvian Andes, and is likely an endemic taxon, emphasizing the importance of biodiversity hotspot studies for future species conservation.

Changes in feeding selectivity of freshwater invertebrates across a natural thermal gradient

Abstract Environmental warming places physiological constraints on organisms, which may be mitigated by their feeding behavior. Theory predicts that consumers should increase their feeding selectivity for more energetically valuable resources in warmer environments to offset the disproportionate increase in metabolic demand relative to ingestion rate. This may also result in a change in feeding strategy or a shift towards a more specialist diet. This study used a natural warming experiment to investigate temperature effects on the feeding selectivity of three freshwater invertebrate grazers: the snail Radix balthica, the blackfly larva Simulium aureum, and the midgefly larva Eukiefferiella minor. Chesson’s Selectivity Index was used to compare the proportional abundance of diatom species in the guts of each invertebrate species with corresponding rock biofilms sampled from streams of different temperature. The snails became more selective in warmer streams, choosing high profile epilithic diatoms over other guilds and feeding on a lower diversity of diatom species. The blackfly larvae appeared to switch from active collector gathering of sessile high profile diatoms to more passive filter feeding of motile diatoms in warmer streams. No changes in selectivity were observed for the midgefly larvae, whose diet was representative of resource availability in the environment. These results suggest that key primary consumers in freshwater streams, which constitute a major portion of invertebrate biomass, can change their feeding behavior in warmer waters in a range of different ways. These patterns could potentially lead to fundamental changes in the flow of energy through freshwater food webs.

MICRODISTRIBUTIONAL VARIABILITY OF LARVAL CADDISFLIES IN MEDITERRANEAN-CLIMATE STREAMS IN NORTHERN CALIFORNIA

ABSTRACT. Knowing how physical and biogenic habitat characteristics affect microspatial variability of larval caddisflies is important to understanding potential population distributions and local species assemblages. We show that larval caddisfly densities and assemblages vary between study reaches and streams on the Angelo Coast Range Reserve in northern California and that species abundance patterns are associated with specific habitat variables. Dicosmoecus gilvipes and Psychoglypha spp. were most dense in 4th-order reaches of the south fork of the Eel River (SFE) and rare or absent in shallow 2nd- and 1st-order reaches of the Elder and Fox Creek tributaries, respectively. Multidimensional scaling (MDS) suggested D. gilvipes densities were associated with water depth, as microdistributions were restricted to depths >40 cm. Microdistributions were also associated with Rivularia-dominated algal patches, but it is doubtful grazing D. gilvipes tracked these cyanobacteria. Psychoglypha spp. were typically found between roughness elements (stones) in relatively deep waters, and MDS suggested that densities of Psychoglypha spp. were related to current velocity Lepidostoma sp. was densest in Fox Creek, and densities of this detritivore were associated with benthic organic matter (BOM). Glossosoma spp. densities were similar among streams (∼25 larvae · m-2) and did not configure around any of the habitat variables used in MDS. Neophylax (likely rickeri), Heteroplectron, Ecclisomyia, and Hydatophylax hesperus were uncommon and found only in either Elder or Fox creeks. Our work shows that larval caddisfly assemblages are more diverse in SFE tributaries than in the mainstem and that species traits and microdistributions are related to local-scale habitat variables in these Mediterranean-climate streams.

Morphological variation in Eunotia serra, with a focus on the rimoportula

Several populations of Eunotia serra Ehrenberg were examined from the eastern and central USA, revealing significant morphological differences from the different sites investigated. Populations from some sites have two rimoportulae per valve, as opposed to other sites where populations have one rimoportula per valve. This last observation raises the question about whether the number of rimoportulae is an important characteristic to use for distinguishing species of Eunotia Ehrenberg. It also raises interesting questions about the phylogenetic relationships between species of Eunotia and other taxa in the Eunotiophycidae D.G. Mann, especially with respect to the significance of rimoportulae in the evolution of the raphe.

Substratum-associated microbiota.

This review of literature on substratumassociated microbiota from 2014 highlights topics on benthic algae and bacteria from a range of aquatic environments, but focuses on freshwater habitats. Advances in pollution and toxin detection, assessment methods, and applications of new technologies are highlighted as are updates in taxonomy and systematics. Aspects of general ecology, water quality, nutrient cycling, trophic interactions, land use changes, biofuels, biofouling, and environmental challenges such as climate change, pollutants, tar sands and fracking, oil spills and nuisance blooms are presented.