Making sense of nickel accumulation and sub-lethal toxic effects in saline waters: Fate and effects of nickel in the green crab, Carcinus maenas.
In freshwater, invertebrates nickel (Ni) is considered an ionoregulatory toxicant, but its mechanism of toxicity in marine settings, and how this varies with salinity, is poorly understood. This study investigated Ni accumulation and physiological mechanisms of sub-lethal Ni toxicity in the euryhaline green crab Carcinus maenas. Male crabs were exposed to 8.2μg/L (the US EPA chronic criterion concentration for salt waters) of waterborne Ni (radiolabelled with (63)Ni) at three different salinities, 20%, 60% and 100% SW for 24h. Whole body Ni accumulation in 20% SW was 3-5 fold greater than in 60% or 100% SW, and >80% of accumulated Ni was in the carapace at all salinities. Ni also accumulated in posterior gill 8, which showed a higher accumulation in 20% SW than in other salinities, a pattern also seen at higher exposure concentrations of Ni (500 and 3000μg/L). Gill perfusion experiments revealed that Ni was taken up by both anterior and posterior gills, but in 20% SW the posterior gill 8, which performs ionoregulatory functions, accumulated more Ni than the anterior gill 5, which primarily has a respiratory function. The sub-lethal consequences of Ni exposure were investigated by placing crabs in Ni concentrations of 8.2, 500, and 3000μg/L at 20, 60 or 100% SW for 24h. In 20% SW, haemolymph Ca levels were significantly decreased by exposure to Ni concentrations of 8.2μg/L or higher, whereas Na concentrations were depressed only at 3000μg/L. Na(+)/K(+)-ATPase activity was inhibited at both 500 and 3000μg/L in gill 8, but only in 20% SW. Haemolymph K, Mg, and osmolality were unaffected throughout, though all varied with salinity in the expected fashion. These data suggest that Ni impacts ionoregulatory function in the green crab, in a gill- and salinity-dependent manner.
Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada; Bamfield Marine Sciences Center, Bamfield, BC V0R 1B0, Canada. Electronic address: blewetta@mcmaster.ca.
Tamzin A
TA
Blewett
Bamfield Marine Sciences Center, Bamfield, BC V0R 1B0, Canada; School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
Chris N
CN
Glover
Bamfield Marine Sciences Center, Bamfield, BC V0R 1B0, Canada; Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
Sandra
S
Fehsenfeld
Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada; Bamfield Marine Sciences Center, Bamfield, BC V0R 1B0, Canada.
Michael J
MJ
Lawrence
Bamfield Marine Sciences Center, Bamfield, BC V0R 1B0, Canada; Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada.
Som
S
Niyogi
Bamfield Marine Sciences Center, Bamfield, BC V0R 1B0, Canada; Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2R2, Canada.
Greg G
GG
Goss
Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada; Bamfield Marine Sciences Center, Bamfield, BC V0R 1B0, Canada; Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
Chris M
CM
Wood
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D003386:Brachyura / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D002118:Calcium / Q000032:analysis; D004789:Enzyme Activation / Q000187:drug effects; D005880:Gills / Q000187:drug effects / Q000378:metabolism; D006458:Hemolymph / Q000737:chemistry; D008297:Male; D009532:Nickel / Q000378:metabolism* / Q000633:toxicity*; D000068357:Saline Waters / Q000737:chemistry; D054712:Salinity; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity
D014874:Water Pollutants, Chemical; D009532:Nickel; D000251:Adenosine Triphosphatases; D002118:Calcium
Crustacean; Invertebrate; Metal; Nickel; Osmoregulation; Salinity