Question

Practice 1:A medium sized lake supports a small population of bald eagle (bird of prey). An BE, which weighs on average 2.5 kg and has a lifespan of 25 years in the wild, eats 2 striped bass(Morone saxatilis) a week; the bassweigh on average 2 kg each and they live for ~7 yrs in the wild. The bassfeed on caddisfly larvae (on average 2.5 kg of caddisfly larvae eaten in a year), which weigh 0.5 g (which they don’t but let’s just say they do). The caddisfly larvae,in turn,feed on aquatic plant material; they eat onaverage 14 g of plant material in their lifetime. The lake is contaminated with mercury. The aquatic plants in the lake take up the mercury at a concentration of 0.0005 mg DDT/g plant. Assume this is a worst case situation where all of the DDT consumed within this food chain stays within the body of the consumer.What is the concentration of DDT consumed by the Caddisfly Larvae? Show your work.What is the concentration of DDT consumed by the Striped Bass? Show your work.What is the concentration of DDT consumed by the Eagle? Show your work.Practice 2:A medium sized lake supports a small population of osprey (bird of prey; Pandion haliaetus). An osprey, which weighs on average 2 kg and has a lifespan of 20 years in the wild, eats 1 laketrout (Onchorhynchus mykiss) a week; the trout weigh on average 2 kg each and they live for ~10 years in the wild. The trout feed on stonefly larvae (on average 3.5 kg of stonefly eaten in a year). The stonefly larvaeweigh 0.5 g (which they don’t but let’s just say they do), which in turn feed on aquatic plant material and eat,on average,12 g of plant material in their short lifespan. The lake is contaminated with PCBs (polychlorinated biphenols), which resides mainly in the sediment at the bottom of the lake. The aquatic plants in the lake use the sediment as their growing substrate, and thus take up the PCBs. The concentration of PCBs in the plants is 0.0009 mg PCB/g plant. Assume this is a worst case situation where all of the DDT consumed within this food chain stays within the body of the consumer.What is the concentration of DDT consumed by theStonefly Larvae? Show your work.What is the concentration of DDT consumed by the Lake Trout? Show your work.What is the concentration of DDT consumed by the Osprey? Show your work

Answer 1

Bald Eagle (weight: 2.5kg) eats - 2 SB/week Striped Bass (weight= 2 kg). eatr 2.5 kg CF / year Caddis fly laware (neight of the time eat-ing in a lifetime Aquatic Plant Material (Take up 0.0005 mg DDT/g plant). DDT connumed by Caddis fly = Ig of plant = 0.0005 mg DDT lug of plant - 19 x 0.005 mg DOT = 0.007 mg DDT DDT commed by striped Bass : I Caddisfa lawae = 0.5g has 0.007 mg DDT SB consume 2.5kg cf / year - 2500 g CF / year 2-soby of 0.035 mg DDT / year 2500g CF = ~35 mg DDT / year

concentration of DDT consumed by Bald Eagle 1 striped Bers- ekg = Orange, 35 mg DDT / yen 2 Striped Bass - Blokady poryworst - 2270 mg. DDT /week tice 2: POLEN Osprey (weight = 2kg) 0 eats= 1 Lake trout / week Lake Trout (weight = 2kg) eats: 3.5kg SF / year Stonefly lamae (weight = oosg) cats= 12g plant material / lifespan Aquatic Plant Material ( PCB = 0.0009 mg PCB lg plant) Ce of DoT in Stonefly lawal = " Ig of plant material = 0.0009 mg PCB 12 g of of plaut= plantz 0.0009x12 mg =0.0108mg PCB 0 in a life span E Conca of PCB connu of PCB connimed by lake trout = 1 Stonefly laware = o.sg has 0.0108 mg PCB | 3.5 kg Stonefly lawae = ~75- 6 mg PCB / year

conccutiation of your consumed by Oprey = 1 lake trout / week =~75.6 mg PCB / week