Donald J. Klemm

Comparing strengths of geographic and nongeographic classifications of stream benthic macroinvertebrates in the Mid-Atlantic Highlands, USA

The US Environmental Protection Agency’s (USEPA) Environmental Monitoring and Assessment Program (EMAP) sampled ∼500 wadeable streams in the Mid-Atlantic Highlands region of the US during the late spring of 1993 to 1995 for a variety of physical, chemical, and biological indicators of environmental condition. Eighty-eight sites that were minimally affected by human activities were chosen to determine the extent to which geographic and stream-based classifications accounted for variation in the composition of riffle macroinvertebrate assemblages. Bray–Curtis similarities among sites were calculated from the relative abundance of macroinvertebrates to assess the strength of classifications based on geography (ecoregions and catchments), habitat (slope and stream order), and water chemistry (conductivity). For comparison, a taxonomic classification (two-way indicator species analysis, TWINSPAN) and a gradient analysis (correspondence analysis, CA) were performed on the macroinvertebrate data. To assess the effect of taxonomic resolution, all analyses were completed at the family level and to lowest practical taxon. The large overall variation within and among ecoregions resulted in a low average classification strength (CS) of ecoregions, although some ecoregions had high CS. Stream order had the highest CS of the habitat and water chemistry classifications. Ecoregion CS increased, however, when stream sites were 1st stratified by stream order (ecoregions nested within stream order). Nested ecoregion CS did not increase within 1st-order streams, yet increased within 2nd- and 3rd-order streams. CA ordinations and TWINSPAN classification showed a clear gradient of streams along stream size (order), with a clear separation of 1st- and 3rd-order streams based on macroinvertebrate composition. The ordinations did not, however, show a distinct clustering of sites on the basis of ecoregions. Overall, the lowest practical taxon level of identification resulted in a clearer pattern of sites in ordination space than did family-level identification, yet only a slight improvement in the different classifications (geographic, habitat, and water chemistry) based on average similarity.

METHODS DEVELOPMENT AND USE OF MACROINVERTEBRATES AS INDICATORS OF ECOLOGICAL CONDITIONS FOR STREAMS IN THE MID-ATLANTIC HIGHLANDS REGION

The Mid-Atlantic Highlands Assessment (MAHA) included the sampling of macroinvertebrates from 424 wadeable stream sites to determine status and trends, biological conditions, and water quality in first through third order streams in the Mid-Atlantic Highlands Region (MAHR) of the United States in 1993–1995. We identified reference and impaired sites using water chemistry and habitat criteria and evaluated a set of candidate macroinvertebrate metrics using a stepwise process. This process examined several metric characteristics, including ability of metrics to discriminate reference and impaired sites, relative scope of impairment, correlations with chemical and habitat indicators of stream disturbance, redundancy with other metrics, and within-year variability. Metrics that performed well were compared with metrics currently being used by three states in the region: Pennsylvania, Virginia, and West Virginia. Some of the metrics used by these states did not perform well when evaluated using regional data, while other metrics used by all three states in some form, specifically number of taxa, number of EPT taxa, and Hilsenhoff Biotic Index, performed well overall. Reasons for discrepancies between state and regional evaluations of metrics are explored. We also provide a set of metrics that, when used in combination, may provide a useful assessment of stream conditions in the MAHR.

Development and evaluation of the Lake Macroinvertebrate Integrity Index (LMII) for New Jersey lakes and reservoirs.

In response to the recent focus by the U.S. EnvironmentalProtection Agency on bioassessment of lakes, a multimetric index was developed for New Jersey lakes and reservoirs using benthicmacroinvertebrates. Benthic samples were collected fromreference and impaired lakes with muck and intermediate sedimentsin central and northern New Jersey during summer 1997. We used astepwise process to evaluate properties of candidate metrics andselected five for the Lake Macroinvertebrate Integrity Index(LMII): Hilsenhoff Biotic Index (HBI), percent chironomidindividuals, percent collector-gatherer taxa, percentoligochaetes/leeches, and number of Diptera taxa. We scoredmetrics as the fraction of the best expected value (based on allsites) achieved at a site and summed them into the LMII. Evaluation of the LMII showed that it discriminated well betweenreference and impaired lakes and was strongly related to severalpotential stressors. Chemical and physical gradients distinguished between reference and impaired lakes, and the LMIIsummarized these gradients well. The LMII corresponded stronglywith land use, but some lakes with more urban land use stillachieved high scores. Based on a power analysis, the ability ofthe LMII to detect differences in condition was sensitive to thenumber of samples from each lake.

Temporal Dynamics of Periphyton Exposed to Tetracycline in Stream Mesocosms

Significant amounts of antibiotics enter the environment via point and nonpoint sources. We examined the temporal dynamics of tetracycline exposure to stream periphyton and associated organisms across a logarithmically dosed-series of experimental mesocosms, designed to mimic natural conditions. Target in-stream tetracycline exposures were based on environmentally relevant concentrations in aquatic ecosystems throughout the United States (<1-100 μg L(-1)). Significant changes in the stream biotic community were observed within 7 days with in-stream tetracycline concentrations as low as 0.5 μg L(-1), including significant changes in antibiotic resistance, bacteria abundance and productivity, algae biomass, cyanobacteria, organic biomass, and nematodes. These effects were magnified with increased exposure time and dosing concentration. Recovery of the periphyton community after 28 days of exposure was dependent upon the tetracycline dose. At the highest doses, 10 and 100 μg L(-1), bacteria productivity recovered; however, bacteria, algae, and nematode abundance did not recover at the same rate and remained low even after a 28-day recovery period (of nondosing). This study demonstrates that tetracycline exposure under near-natural conditions and at concentrations currently observed in aquatic environments may have important consequences for the structure and function of stream periphyton and, potentially, public health via increasing resistance of naturally occurring bacteria.

PERSPECTIVES ON USE OF A MULTIMETRIC LAKE BIOASSESSMENT INTEGRITY INDEX USING BENTHIC MACROINVERTEBRATES

Abstract A lake bioassessment integrity index (LBII) derived from 12 macroinvertebrate metrics was used to evaluate the biological integrity of 19 lakes in five New England States (Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont). Of the 19 lakes classified according to temperature and size (warm, small; warm, large; cold, small; cold, large), 15 lakes had anthropogenic disturbances (including residential, agricultural, silvercultural, and fish stocking), and one minimally disturbed reference lake was selected from each category. The bioassessment index successfully ranked the biological integrity for 17 of the 19 lakes. Index scores of anthropogenically disturbed lakes were significantly higher (P <0.05) than index scores of reference lakes with little disturbance in each temperature and size category, indicating that the index may be useful in separating impacted from non-impacted lakes in the New England States.

Placobdella cryptobranchii (Rhynchobdellida: Glossiphoniidae) on Cryptobranchus alleganiensis bishopi (Ozark Hellbender) in Arkansas and Missouri

Abstract Placobdella cryptobranchii is a rarely collected leech of the Ozark hellbender (Cryptobranchus alleganiensis bishopi) in northern Arkansas and southern Missouri, U.S.A. Between October 2002 and August 2005, 58 hellbenders were examined from Eleven Point River (Randolph Co., Arkansas and Oregon Co., Missouri), the north fork of the White River (Ozark Co., Missouri), and the Spring River (Fulton Co., Arkansas). Forty-one of the 58 hellbenders (70.7%) were infested with 1–140 leeches with a mean intensity (±SD) of 8.7 (±22.1) and a relative abundance (±SD) of 6.3 (±18.9). Contingency table analysis and t-tests revealed no significant differences in prevalence and mean intensity among various years and localities sampled. Leech size did not substantially change over the time period sampled. The dorsal pigmentation of live specimens of P. cryptobranchii is described for the first time.

Life History and Distribution of the Leech Oligobdella biannulata (Moore, 1900) (Euhirudinea: Glossiphoniidae)

Abstract Oligobdella biannulata is a rare, endemic leech species originally described from a mountain stream near Blowing Rock, North Carolina, U.S.A. Specimens of O. biannulata were collected seasonally (fall 1999–summer 2002), documenting new county records from North Carolina and South Carolina and new state records from Georgia and Tennessee, U.S.A. Fifty-one percent of Desmognathus quadramaculatus and 50% of Desmognathus marmoratus were parasitized with O. biannulata. Between late May and early July, O. biannulata leaves its salamander host to lay 15–30 bright yellow, yolky eggs and brood them on its ventral surface. Eggs hatch in 10–20 d, and in about 50 d both hatchlings and adult search for a blood meal. Oligobdella biannulata reattaches to its host between late August and early October. When a desmognathine salamander host is found the adult leech attaches and hatchlings leave the adult, attaching singly or in clusters on the limbs or axillary and inguinal regions of the salamander, blood feeding, and overwintering on the host.

An electrospray ionization mass spectrometric study of the giant, extracellular, hexagonal bilayer hemoglobin of the leech Haemopis grandis provides a complete enumeration of its subunits

Abstract The complex, multiply charged electrospray ionization mass spectra of the extracellular, ∼3500 kDa, hexagonal bilayer hemoglobin from the leech Haemopis grandis and its carbamidomethylated, reduced and reduced/carbamidomethylated forms were deconvoluted using a maximum entropy approach to provide the corresponding zero-charge spectra. Three groups of peaks were observed: monomeric globin chains a1–a4 at ∼17 kDa (16 634.1, 17 013.4, 17 592.9, and 17 573.3 Da with relative intensities of 16:4:12:1, respectively), linker chains L1–L3 at ∼24 kDa (24 004.2, 24 449.2 and 24 548.3 Da, with relative intensities of 5:1:2.5, respectively) and subunits D1 and D2 at 32 501.1 and 32 629.6 Da, respectively, with equal intensities. Reduction of the native hemoglobin with dithiothreitol resulted in a decrease in the mass of linker L2 by 115.1 Da, indicating cysteinylation, the disappearance of subunits D1 and D2 and the concomitant appearance of globin chains b (16 098.8 Da), c1 (16 403.9 Da), and c2 (16 532.5 Da), suggesting that subunits D1 and D2 are disulfide-bonded dimers b + c1 and b + c2, respectively. All the globin chains appear to have one intrachain disulfide bond, and globins b, c1, and c2 have an additional Cys which forms the interchain disulfide bond in D1 and D2. The linkers L1–L3 contain 10, 9, and 10 Cys residues, respectively, all forming intrachain disulfide bonds, except for the odd residue in L2 which is proposed to be the site of cysteinylation. The relative intensities of the three groups of peaks a1 + a2 + a3 + a4:L1 + L2 + L3:D1 + D2 are 1.65:1.7:0.8 in native hemoglobin. All the subunits in a second sample evinced substantial glycosylation, with up to five hexoses per subunit. A model of the quaternary structure of Haemopis hemoglobin is proposed, consisting of 72 monomeric globins and 36 globin dimers for a total of 144 globin chains and 42 linkers with a calculated total mass of 3506 kDa.

Biology of the Leech Actinobdella inequiannulata Moore, 1901 (Annelida: Hirudinea: Rhynchobdellida: Glossiphoniidae), Parasitic on the White Sucker, Catostomus commersoni Lacepède, 1803, and the Longnose Sucker, Catostomus catostomus Forster, 1773, in Algonquin Provincial Park, Ontario, Canada

Abstract Actinobdella inequiannulata was found on the white sucker, Catostomus commersoni, and less frequently on the longnose sucker, Catostomus catostomus, in Algonquin Provincial Park, Ontario, Canada. Catostomus commersoni parasitized with Act. inequiannulata was collected from July to October 1973 and May to October 1974. In May and October, less than 3% of the fish carried leeches. In July, 80% of the fish were parasitized with an average of 1.5 leeches/fish. Observations on leech weight suggest that young leeches attach to fish from May to September, some mature in July, and a second generation of leeches reparasitize the fish in August and September. The mean size of leeches on suckers increased from May until July, after which the size remained relatively constant. Leeches produced characteristic lesions on the opercula of suckers. Fully developed lesions on fish opercula produced by aggregated leeches had varying amounts of central erosion, extravasation, dermal and epidermal hyperplasia, and necrosis.

Distribution of the Genus Philobdella (Macrobdellidae: Hirudinida), Including New Locality Records from Arkansas and Oklahoma

Abstract Philobdella gracilis Moore, 1901 (Macrobdellidae: Hirudinida) is reported from Arkansas and Oklahoma for the first time. Specimens were collected in creeks and ponds. The Mississippi drainage distribution of P. gracilis and eastern distribution Philobdella floridana were confirmed by reexamination of museum specimens.