n, p, and isotopes from the nearshore/offshore lake erie ...€¦ · n, p, and isotopes from the...

N, P, and isotopes from the nearshore/offshore Lake Erie nutrient study (NOLENS).

C.M. Pennuto1,2, A. Pérez-Fuentetaja1,2, A. Karatayev1,2, L. Burlakova1,2, G. Matisoff3, D. Bade4, J. Conroy5, E.A. Marschall5, and J. Kramer6.

1Biology Department, Buffalo State College, Buffalo, NY 2Great Lakes Center, Buffalo State College, Buffalo, NY

3Dept of Geological Sciences, Case Western Reserve University, Cleveland, OH 4Biology Department, Kent State University, Kent, OH

5Biology Department, The Ohio State University, Columbus, OH6National Center for Water Quality Research, Heidelberg University, Tiffin, OH

Sampling approach

• NS-to-OS transects bracketing major tribs to C & E basins…also allowed

coordination with other trib/watershed groups

• NS: R/V J.J. Freidhoff/whalers; OS: R/V Lake Guardian

• fixed stations (2, 5, 10, 20 m), June and late Aug/early Sept sampling

• quantify water column and benthic P pools…bacterial, phytoplankton, 3

zooplankton sizes, Dreissena mussels, dominant infaunal/epifaunal,

Cladophora, sediments (both mussel bed and non-mussel bed)

• estimate fluxes…bacterial and phytoplankton productivity, sedimentation

• link pools and fluxes via stable isotope analyses and hydrodynamic model of

particle transport

[P] in solid fractions[P] in benthic solid fractions

0

20

40

60

80

100

West-central (Sandusky)

Central (Grand) East (Cattaragaus)

Me

an [

P]

(m

g/g

)

Location

Sediment

Dreissena

Benthos

Cladophora

0

25

50

75

100

125

150

175

200

West-central (Sandusky)

Central (Grand) East (Cattaragaus)

Me

an d

ry m

ass

(g

/m2 )

Location

Sediment (*100-1)

Benthos

Dreissena

Cladophora

Benthic matrix quantities

Benthic matrix P amounts

0

25

50

75

100

West-central (Sandusky)

Central (Grand) East (Cattaragaus)

Me

an P

(g

/m2 )

Location

Sediment

Benthos

Dreissena

Cladophora

0

4

8

12

16

East (Catt Creek) Central (Grand) West-central (Sandusky)

[P]

(mg

/g)

20-m depth June

20-m depth September

0

5

10

15

20

West-central (Sandusky) Central (Grand) East (Cattaragaus)

Me

an m

uss

el

P (

mg

/m2 )

Location

2

5

10

20

Dreissena P amountsDepth

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

2 5 10 20 (14)

[TP

] (m

g/L)

Depth (m)

Water column [TP]Sandusky (west-central)Grand (central)Cattaraugus (east)June = black; Sept = white

0

2

4

6

8

10

12

14

2 5 10 20 (14)

Ch

l a(m

g/L)

Depth (m)

Sandusky (west-central)Grand (central)Cattaraugus (east)June = black; Sept = white

Water column [chl a]

0

200

400

600

800

1000

1200

1400

1600

2 5 10 20 (14)

Alg

al P

tu

rno

ver

(min

)

Depth (m)

Sandusky (west-central)Grand (central)Cattaraugus (east)June = black; Sept = white

Water column algal P-limitation

0

2

4

6

8

10

12

West (Sandusky) Central (Grand) East (Cattaragaus)

δN

1520-63 μm

63-210 μm

-30 -25 -20 -15 -10 -5 0

δN

15

δC13

Amphipod

Plankton

Oligochaete

Chironomid

Detritus

Benthos

Dreissena

Sediment

2

4

6

8

10

Results summary

• Distinct NS-to-OS reductions in water column [TP] at all 3 locations, WC & E basinincrease [TP] with season, but C decreased with season

• Algal abundance (chl a) matched [TP] in both seasons and across basins, decliningNS to OS and increasing or decreasing with [TP]; generally declining west to east

• Algal and bacterial communities were P-limited in the C, but not the WC or Ebasins in fall

• WC basin plankton exhibits a slightly higher δN, suggesting either longer chainsor a different basal resource

• The majority of organic particulate P resides in Dreissena tissues, but mussel abundance is very different in the basins and at different depths

• Sediments harbor the largest pool of P in the lake. Although C basin sediments have the highest [P] averaged across all depths, and the highest P pool, WC basin sediments have the highest OS [P]

Acknowledgments

GLNPO grant to CMP et al.

NSF-URM grant to CMP for summer students

Collaborators: G. MatisoffD. Bade

J. KramerS. Karatyev

A Perez-FuentatajaJ. Conroy

L. Burlakova

Students: M. HadjukC. Janik

C. VarascoC. Todd

K. James