Nitrogen Cycling Processes Across an Oyster Aquaculture Chronosequence

Robinson W. Fulweiler • Boston University • Department of Earth and Environment • Department of Biology

40% increase since ~1900s

~50% of the Global Population – Alive today – because of this process.

Erisman et al., Nature Geoscience, 2008

N Loading and Aquatic ecosystem response

• Increased algal productivity

• Harmful algal blooms

• Formation of nuisance algal mats

• Low oxygen conditions

• Fish kills - fin and shell

• Loss of biodiversity

• Loss of submerged aquatic vegetation

Sybil Seitzinger, 2003

Denitrification: NO3- N2 Removes nitrogen from the system

Atmosphere(km)

Water Column

(m)

Sediment(cm)

Detrital Organic matter

Organic matter

NH4+

NH4+

NO2-

NO3-

N2

N2O

N2O

N2N2O

Photosynthesis

Bacterial degradation

Bacterial degradation

Nitrification

N2

Denitrification

Aerobic conditions

Anaerobic conditions

Nitrifi

catio

n

“…the old oysterman knew, there’s no betterplace to grow oysters than in Rhode Island.”

-Photo & Quote from Michael A. Rice, 2006

Beutel 2012

Millions of Oyster Aquaculture Pieces Sold Over the Last Sixteen Years

0

10

20

30

40

50

60

70

80

90

Aquaculture Oyster Cultch Control

SOD

(m

mol

O2-

O m

-2hr

-1)

Sediment Oxygen Demand

Spring

Summer

Fall

-1500

-1000

-500

0

500

1000

1500

2000

Aquaculture Oyster Cultch Control

N2

flux

(um

ol N

2-N

m-2

hr-1

)Net N2 Fluxes

Spring

Summer

Fall

Carey et al. 2014 ASLO Poster, Manuscript In Prep,

Acknowledgements:

• RI Sea Grant

• Dave Beutel, CRMC

• Jim Arnoux, East Beach Oysters (http://eastbeachblondes.com/)

• Suzy Ayvazian, EPA

• Boze Hancock, TNC

• Joanna Carey, MBL

• Boston University

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