Manganese :: all ecosystems

Key Concerns

Symptoms of manganese toxicity to terrestrial plants vary widely between species. They include marginal chlorosis, necrotic lesions and distorted development of the leaves (Woolhouse 1983). In plants, manganese tends to accumulate in the shoots, rather than roots, resulting in symptoms occurring in the leaves (Loneragan 1988).

Arable habitats - substantial genetic variation for managanese tolerance exists in crop plants such as common beans (Phaseolus vulgaris) (Foy et al. 1998; Gonzalez and Lynch 1999), mung bean (Vigna radiata) (Rout et al. 2001) and rice (Oryza sativa) (Rout et al. 2001; Lidon 2002). Some members of the Ericaceae family such as blueberry are manganese accumulators, and can contain manganese concentrations in excess of 2000 to 4000 mg/kg without any effects on growth or visual symptoms of toxicity (Korcak 1988).

Bogs, wetland and heath - there is a paucity of data on the effects of manganese on species indicative of bog, wetland or heathland ecosystems. Symptoms of manganese toxicity to terrestrial plants vary widely between species. They include marginal chlorosis, necrotic lesions and distorted development of the leaves (Woolhouse 1983). In plants, manganese tends to accumulate in the shoots, rather than roots, resulting in symptoms occurring in the leaves (Loneragan 1988).

Coastal and rocky habitat – the 5 day-EC50 for growth of the marine diatom Ditylum brightwelliiw was 1.5 mg/l (Canterford and Canterford 1980). A 21 day EC50 (total cell volume) of the alga Chlorella stigmatophora was 50 mg/l (Christensen et al. 1979).

Forty eight hour LC50 values for marine invertebrates include 16 mg/l (American oyster Crassostrea virginica) (Calabrese et al. 1973) and 51.8 mg/l (brine shrimp, Artemia salina) (Gajbhiye and Hirota 1990). A 48 hour EC50 (abnormal larval development) for mussel (Mytilus edulis) was 30 mg/l (Morgan et al. 1986). A reduction in survival and hatching of yellow crab (Cancer anthonyi) embryos was reported following a 7day exposure to manganese concentrations !Y 0.01mg/l (Macdonald et al. 1988).

There is a paucity of data on the effects of manganese on saltwater fish.

Freshwater – the 72h-EC50 for growth of the alga Selenastrum capricornutum was 8.3 mg/l (Reimer 1999). Twelve day EC50 values for effects on growth and chlorophyll in the alga (Scenedesmus quadricauda) were 5 and 1.9 mg/l, respectively (Fargasova et al. 1999).

Forty eight hour EC50 (immobilisation) values for Daphnia magna exposed to manganese ranged from 0.8 to 76.3 mg/l, with increasing toxicity reported with decreasing water hardness (Reimer 1999). Acute LC50 values for other invertebrates include 38.7 mg/l for a rotifer (Brachionus calyciflorus) (Couillard et al. 1989), 333 mg/l for an isopod (Asellus aquaticus) (Martin and Holdich 1986) and 694 mg/l for an amphipod (Crangonyx pseudogracilis) (Martin and Holdich 1986).

Ninety six hour LC50 values for coho salmon (Oncorhynchus kisutch) exposed to manganese ranged from 2.4 to 1704 mg/l, with toxicity increasing with decreasing water hardness (Reimer 1999). Corresponding LC50 values for other species of freshwater fish include 4.8 mg/l (rainbow trout; Oncorhynchus), (Davies and Brinkmand 1994), 3.8 to 49.9 mg/l (brown trout, Salmo trutta) (Davies and Brinkmand 1994; Davies and Brinkmand 1995), 3010 mg/l (channel catfish, Channa punctatus) (Garg et al. 1989a) and 3350 mg/l (fossil catfish, Heteropneustes fossilis) (Garg et al. 1989b).

Grassland – symptoms of manganese toxicity to terrestrial plants vary widely between species. They include marginal chlorosis, necrotic lesions and distorted development of the leaves (Woolhouse 1983). In plants, managanese tends to accumulate in the shoots, rather than roots, resulting in symptoms occurring in the leaves (Loneragan 1988).

Adarve et al (1998) exposed four grassland species to landfill leachate treatments which contained manganese concentrations ranging from 1.50 to 5.30mg/l. The species used were clustered clover (Trifolium glomeratum), cotton clover (Trifolium glomeratum), wall barley (Hordeum murinum L.) and soft brome (Bromus hordaceus). Concentrations of manganese in exposed plants were not correlated with exposure concentration although they were higher than those from the control group. Concentrations in all plants were within the 20 to 300 mg/l range which is normally found in clover and grasses, and below the 300-500 mg/l range which is considered to be toxic (Adarve et al. 1998).

Woodland and hedgerow –  symptoms of manganese toxicity to terrestrial plants vary widely between species. They include marginal chlorosis, necrotic lesions and distorted development of the leaves (Woolhouse 1983). In plants, manganese tends to accumulate in the shoots, rather than roots, resulting in symptoms occurring in the leaves (Loneragan 1988).

Foliar toxicity has been reported in white birch (Betula platyphylla japonica) hydroponically exposed to manganese. Brown speckle at the leaf marginal and interveinal areas was reported in older leaves at exposure concentrations exceeding 1 mg/l. At 50 mg/l, entire chlorosis of younger leaves was also reported (Kitao et al. 2000). Chlorosis and foliar necrosis have also been reported in the seedlings of four species of deciduous trees following exposure to 1mg/l manganese solutions. The species tested were Betula ermanii, Alnus hirsute, Ulmus davidiana japonica and Acer mono. Reduced photosynthesis rate was also reported in these plants. Chlorosis has also been reported in field studies, including Douglas fir (Pseudotsuga menziesii viridis) trees which had high manganese concentrations. (Kaus and Wild 1998).

Manganese concentrations exceeding 600 mg/kg have been reported in needles of Balsam fir (Abies balsamea) growing in rural mountain areas. These high concentrations were due to atmospheric contamination (Lin et al. 1995). Concentrations of manganese in blue spruce (Picea pungens) xylem were similar in trees growing beside roads and those distant from the road, despite a ten fold difference in soil concentrations (Forget et al. 1994). Concentrations of manganese in birch (Betula pubescens tortuosa Ledeb) leaves were 5 to 10 times higher in trees growing near a nickel/copper smelter compared to regional background concentrations (Kozlov et al. 1995).

Manganese concentrations greater than 3mM in agar have been shown to inhibit the growth of the epiphytic lichen Hypogymnia physodes in laboratory studies (Hauck et al. 2002). Similarly, field studies have shown that the cover of H. physodes to be negatively correlated with the manganese concentration in the bark of the Norway spruce (Picea abies) growing in Germany (Hauck et al. 2001).

Additional Comments

Manganese is an essential element for both plants and animals (Underwood 1977; Woolhouse 1983). Nutritional requirement for terrestrial plants range from 10 to 50 mg/kg plant tissue (Hannam and Ohki 1988; Reisenauer 1988). However excess manganese will lead to toxicity. Manganese toxicity is a major limiting factor on acidic, poorly drained or steam sterilized soils. The solubility of manganese increases with increasing acidity. Manganese is generally toxic at soil pH values <5.5. (Foy et al. 1978; Foy et al. 1988).