The Use of Benthic Filter Feeders to Mitigate Eutrophication in Coastal Systems
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Transcript of The Use of Benthic Filter Feeders to Mitigate Eutrophication in Coastal Systems
Lynn Ficarra
The Use of Benthic Filter Feeders to Mitigate Eutrophication in Coastal
Systems
“an increase in the rate of supply of organic matter to an ecosystem.” (Nixon 1995)
N & Pland clearing, sewage, fertilizer, animals, fossil
fuels, industryPhytoplankton (Paerl 1988, Diaz and Rosenberg 2008)
Block sunDie, sink to bottom, microbial respiration,
hypoxia
Eutrophication
Remove phytoplankton, nutrients, organic materials, bacteria, and much much more!
Filter Feeders!
(Ruesink et al. 2005, Gili and Coma 1998, Levinton 1972).
Filtration rate Depends on species, size, water velocity,
temperatureEfficiency of particle retention
Depends on filtering structure
(Comeau et al. 2008, Rice 2001, Eastern Oyster Biological Review Team 2007)
Particle Capture
Gills (Riisgard 1988)
Parallel filamentsCiliary tracts: create current, capture particles
Particles sorted (Newell 2004)
Rejected: pseudofecesDigested: feces
Mucus-coated aggregates Released to benthos
Bivalves
Filtration Rate (Rank)
Retention of Particles >4-
5µm
Retention of 2µm
Particles
Crassostrea virginica (Eastern oyster)
1 100% 50%
Geukensia demissa (Ribbed mussel)
2 100% 35-75%
Argopecten irradians (Bay scallop)
2 100% 15%
Brachiodontes exustus (Scorched mussel)
3 100% 35-75%
Spisula solidissima (Atlantic surfclam)
3 100% 35-75%
Mercenaria mercenaria (Northern Quahog)
4 100% 35-75%
Riisgard 1988
Mussels and eastern oysters performed well in both studies
Crassostrea virginicus and Mytilus edulisNative to east coast of U.S.
Capture Rate (mgC m-
2d-1)
Aulacomya ater (mussel) 1787
Chlamys islandica (scallop) 3621
Crassostrea virginica (oyster)
573
Geukensia demissa (mussel) 30
Mercenaria mercenaria (quahog)
351
Ostrea edulis (oyster) 9-30
Gili and Coma 1998
Atlantic coast of U.S.0.6-5 m depth20-30°C optimal
Survive freezing and >45°C, feeding rate affectedSurvive at salinities of 5-40 pptFiltration rate up to 30-40 L h-1
Create oyster reefsPromotes biodiversitySubstrate for more suspension feeders
(Ruesink 2005, MacKenzie 1996, Stanley and Sellars 1986, Galtsoff 1964, Shumway 1996, Eastern Oyster Biological Review Team 2007, Pechenik 2005)
Crassostrea virginica (Eastern Oyster)
Coast of Canada to North Carolina1-10 m depth5-20°C optimal
Survive freezing and up to 29°C>18 ppt ideal
Survive low salinities 4-18 ppt, growth slowedFiltration rate 1.34-2.59 L h-1
Mussel bedsIncreases biodiversitySubstrate for more filter feeders
(Zagata et al. 2008, Goulletquer 2012, Bayne and Widdows 1978)
Mytilus edulis (Blue Mussel)
Filtration rates at 9°C (Comeau et al. 2008)
M. edulis: 1.82-2.90 L h-1 C. virginica: 0.05-1.21 L h-1
Optimal conditions: C. virginica faster than M. edulis
Cold conditions: M. edulis fasterUse both for eutrophication control
C. virginica vs. M. edulis
Average filtering rate at optimal conditions for 44 filter feeding species is 7.8 L g-1h-1 dry weight (Pomeroy, D’Elia, and Schaffner 2006)
Sponges (Milanese et al. 2003)
retain up to 80% suspended particlesCapture small particles that others miss
(bacteria)
Other Filter Feeders
Liverpool (Allen and Hawkins 1993)
Mussels introduced to eutrophic water surrounding docks
Two years later water quality and oxygen levels in water column and sediments improved
Chesapeake Bay (Newell 1988)
Pre-1870: oysters filter bay in 3-6 daysNow: 325 days
Case Studies
Competitive exclusion (Ruesink 2005)
Toxic shellfish (MacKenzie et al. 2004)
Invasive species (Ruesink 2005)
HitchhikersPathogens (Moss et al. 2007)
Asian oyster, Chesapeake Bay2 protist parasites not found in U.S. watersViruses, cestodes, other protist parasites
Negative Impacts
Refer to Accompanying Paper
References