James F. Haney

Field studies on zooplankton‐cyanobacteria interactions

Abstract Correlative field evidence suggests that large grazers such as Daphnia pulex promote the growth of colonial cyanobacteria by selectively eating competitive phytoplankton. This is supported by experimental evidence that (1) in eutrophic lakes dominated by cyanobacteria grazing by zooplankton on small particles is often > 100% day‐1, and (2) colonial cyanobacteria are generally not grazed as rapidly as smaller phytoplankton. Cyanobacteria generally have deleterious effects on grazing zooplankton. Filamentous cyanobacteria such as Anabaena and Oscillatoria can inhibit filtering by cladocerans, reducing growth and reproduction. Detrimental effects on zooplankton via nutritional deficiencies and toxins of cyanobacteria have been demonstrated in the laboratory but not in the field. Grazing on colonial cyanobacteria by zooplankton appears to be an important trophic link in tropical lakes. Generally, calanoid copepods seem best adapted to utilising large cyanobacteria. The generalisation that, with incre...

A cluster of amyotrophic lateral sclerosis in New Hampshire: A possible role for toxic cyanobacteria blooms

Abstract Cyanobacteria produce many neurotoxins including ß-methylamino-L-alanine (BMAA) that has been liked to amyotrophic lateral sclerosis (ALS) and neurodegenerative disease. A number of ALS cases have been diagnosed among residents of Enfield, NH, a town encompassing a lake with a history of cyanobacteria algal blooms. To investigate an association between toxic cyanobacterial blooms in New Hampshire and development of ALS, we reviewed records from our institution and other community databases to obtain demographic information on patients diagnosed with ALS within New England. We identified nine ALS patients who lived near Lake Mascoma in Enfield, NH, an incidence of sporadic ALS that is 10 to 25 times the expected incidence of 2/100,000/year. We suggest that the high incidence of ALS in this potential cluster could be directly related to chronic exposure to cyanobacterial neurotoxins such as BMAA. Possible routes of toxin exposure include inhalation of aerosolized toxins, consuming fish, or ingestion of lake water. Further investigation, including analysis of brain tissue for cyanobacterial toxins, will be helpful to test for an association between BMAA and ALS.

Activity of cyanobacterial and algal odor compounds found in lake waters on green alga Chlorella pyrenoidosa growth

Volatile organic compounds produced by cyanobacteria and algae in freshwater lakes and contributing to the odour of lakes were tested for their ability to inhibit the growth of the green alga Chlorella pyrenoidosa by the paper disk-agar plate method. Geosmin, β-cyclocitral, α- and β-ionones, and geranylacetone exhibited inhibitory activity by diffusion in the 2-5 mg ml−1 range. α- and β-Ionones and geranylacetone showed inhibition through the vapor phase at 10 mg ml−1. Dimethyl disulfide showed no inhibition at 10 mg ml−1. The norcarotenoids, which are prominent contributors to the odour of lake waters, were not significantly active in inhibiting the growth of Chlorella, with activity in the same range as monoterpene alcohols in general.

Oscillations in the reproductive condition of Diaptomus leptopus (Copepoda: Calanoida) and their relation to rates of egg-clutch production

SummaryIsolated female D. leptopus oscillate between gravid and nongravid reproductive conditions. When gravid, the oviducts are visible as a pair of dark bands lateral to the digestive tract. Periodically the females revert to a nongravid condition by releasing all the unfertilized oocytes into the environment. The oviducts then remain transparent until they refill with ripe gametes.The characteristics of this gametogenic cycle were defined at 18° C using females cultured under controlled conditions. The average period of the cycle was 4.4 days, with a gravid phase (dark oviducts) of 3.4 days and a nongravid phase (clear oviducts) of 0.9 days. Observations made in situ confirmed the oscillatory nature of the changes in reproductive status.The duration of the nongravid phase was shown to represent the minimal time interval between successive clutches of fertilized eggs. Estimates of maximal rates of clutch production based on this measure were more than three times higher than those based on the duration of embryonic development.Since unfertilized oocytes disintegrate upon extrusion, a considerable amount of reproductive material may be wasted regularly. A turnover rate of 5.6% body weight (dry) day-1 was calculated for isolated females at 18° C. A model used to estimate the frequency of mating interactions indicated that the probability of oocyte extrusion in lakes may be high and the impact on nutrient pools could be substantial. Up to 0.12 μg phosphorus mg-1 h-1 may be released in the form of unfertilized oocytes.

Inhibition of Chlorella growth by the lipids of cyanobacterium Microcystis aeruginosa

The total lipids of the cyanobacterium Microcystis aeruginosa have been isolated and fractionated into its components. Of these lipid components, only the fatty acid-containing fraction inhibited the growth of the green alga Chlorella pyrenoidosa. The inhibitory activity appears to be due to linoleic and linolenic acids, which are both present in significants quantities. These acids may be the substances responsible for the reported toxicity of Microcystis aeruginosa to Chlorella.

Detection of cyanotoxins, β-N-methylamino-L-alanine and microcystins, from a lake surrounded by cases of amyotrophic lateral sclerosis.

A cluster of amyotrophic lateral sclerosis (ALS) has been previously described to border Lake Mascoma in Enfield, NH, with an incidence of ALS approximating 25 times expected. We hypothesize a possible association with cyanobacterial blooms that can produce β-N-methylamino-l-alanine (BMAA), a neurotoxic amino acid implicated as a possible cause of ALS/PDC in Guam. Muscle, liver, and brain tissue samples from a Lake Mascoma carp, as well as filtered aerosol samples, were analyzed for microcystins (MC), free and protein-bound BMAA, and the BMAA isomers 2,4-diaminobutyric acid (DAB) and N-(2-aminoethyl)glycine (AEG). In carp brain, BMAA and DAB concentrations were 0.043 μg/g ± 0.02 SD and 0.01 μg/g ± 0.002 SD respectively. In carp liver and muscle, the BMAA concentrations were 1.28 μg/g and 1.27 μg/g respectively, and DAB was not detected. BMAA was detected in the air filters, as were the isomers DAB and AEG. These results demonstrate that a putative cause for ALS, BMAA, exists in an environment that has a documented cluster of ALS. Although cause and effect have not been demonstrated, our observations and measurements strengthen the association.

Inhibition of Chlorella growth by degradation and related products of linoleic and linolenic acids and the possible significance of polyunsaturated fatty acids in phytoplankton ecology

The activity of the degradation products of linoleic and linolenic acids in inhibiting the growth of the green alga Chlorella pyrenoidosa was determined using the paper disk-agar plate method. Although hydroperoxides derived from these acids and aldehyde biodegradation products and other related aldehydes and alcohols showed inhibitory activity, it is concluded from the weakness of the activities that the inhibitory effects of polyunsaturated fatty acids(PUFAs) on Chlorella growth is due mainly to the acids themselves and not their degradation products. The evidence for the possible ecological role of PUFAs as toxic agents against phytoplankton is presented.

Pterins of the cyanobacterium Aphanizomenon flos-aquae

The cyanobacterium Alphanizomenon flos-aquae contains various glycosides of a pterin that had previously been tentatively identified as 6-(threo-1,2-dihydroxypropyl)-pterin. The pterin is now identified as 6-(l-threo-1,2-dihydroxypropyl)pterin(6-l-threo-biopterin) by NMR and mass spectrometry, thinchromatographic comparisons with authentic samples and by optical rotation. The 6-l-threo-biopterin glycoside-1 from toxic strain NH-1 gave rise to xylose and glucose on hydrolysis, whereas its glycoside-2 from Cambridge Collection and nontoxic NH-1 strains gave mannose and glucose. This pterin may be a useful marker for certain species of cyanobacteria.

Direct observation of toxic effects of cyanobacterial extracellular products on Daphnia

The filtrate from a suspension of the cyanobacterium Anabaena minutissima var. attenuata depressed thoracic limb beat frequency of Daphnia carinata by 38–45% in a food-free medium. Repeated exposure to the filtrate produced a similar depression of activity with full or neary full recovery. Response time to the filtrate was 5–8 min and recovery time was 8–12 min. The dose effect on limb beat frequency was continuous, linear, correlated with increased concentration and with no threshold. There was no relationship between body length and limb beat frequency.The interaction between toxicity and food concentration was tested using the diatom Cyclotella suspended in Anabaena filtrate. Daphnia limb beat frequency was depressed by 62%.

Lipids of cyanobacteriumAphanizomenon flos-aquae and inhibition ofChlorella growth.

The inhibition of the growth of the green algaChlorella pyrenoidosa by the lipids of the cyanobacteriumAphanizomenon flos-aquae is associated with the fractions containing long-chain unsaturated fatty acids. A sterol present inAphanizomenon has been identified as poriferasterol.