the grass is always greener: seagrass ecology in south floridaseagrass.fiu.edu › resources ›...
TRANSCRIPT
![Page 1: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/1.jpg)
The Grass is Always Greener: Seagrass Ecology in South Florida
R.P
. van D
am
James W. Fourqurean Biological Sciences and Southeast Environmental Research Center, Florida International University
Ocean Life Lecture Series, Florida Keys Cultural Center, Ley Largo February 17, 2012
![Page 2: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/2.jpg)
Outline
• What are seagrasses?
• What is the global status of seagrass ecosystems?
– Seagrass services
– Seagrass history
– Seagrass pressures
– Seagrass response
– Human response
• What is the local status of the seagrasses in south Florida? – signs of trouble in paradise
![Page 3: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/3.jpg)
Seagrasses are flowering plants that live submerged in the sea
![Page 4: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/4.jpg)
The seagrasses are an ecological group, NOT a taxonomical unit
A plant is called a seagrass if it: 1. Grows when fully submerged 2. Is securely anchored by a root system 3. Is adapted to live in salt water 4. Has flowers that are pollinated under water 5. Can compete with other organisms in the sea
![Page 5: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/5.jpg)
Seagrass or seaweed?
300 BC: Seagrasses are a type of “seaweed”
- Theophrastus (300 BC), Enquiry into Plants
![Page 6: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/6.jpg)
No. Species Seagrasses •50-60 spp. Flowering plants •235,000 spp. Marine plants •60,000 spp. Phytoplankton • 50,000 spp. Macroalgae - seaweeds • 10,000 spp. Seagrasses (No. Genera) •7 tropical (Halodule, Cymodocea, Syringodium, Thalassodendron, Enhalus, Thalassia, Halophila), •5 temperate (Zostera, Phyllospadix, Heterozostera, Posidonia, Amphibolis) •1 cosmopolitan (Ruppia)
Evolution
![Page 7: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/7.jpg)
![Page 8: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/8.jpg)
![Page 9: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/9.jpg)
![Page 10: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/10.jpg)
![Page 11: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/11.jpg)
![Page 12: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/12.jpg)
Seed
Male flower
Female flower Juvenile
Juvenile
Fruit
LIFE CYCLE of
Thalassia testudinum
Male clone
Female clone
![Page 13: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/13.jpg)
Seagrasses are abundant in tropical and temperate regions
Halophila:
Bocas del Toro, Panama
Thalassia:
Kuna Yala, Panama
Ruppia:
Morro Bay, USA
Zostera:
Ria Formosa, Portugal
![Page 14: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/14.jpg)
Seagrass provides critical food source in tropical regions
R.P
. van D
am
J. K
enw
ort
hy
Manatee (Trichechus)
In Thalassia meadow,
Puerto Rico
Green Sea Turtle (Chelonia)
In Thalassia and
Syringodium meadow,
Yucatan, Mexico
![Page 15: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/15.jpg)
Seagrass provides critical habitat in temperate regions
G. K
endrick
G. P
erg
ent
Seahorse (Hippocampus)
In Cymodocea meadow,
Mediterranian Sea
Zebra fish (Girella)
In Posidonia meadow,
Perth, Western Australia
![Page 16: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/16.jpg)
Seagrass provides valuable fisheries resources
![Page 17: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/17.jpg)
Nutrient processors: Seagrass beds absorb and transform nutrients in the marine environment
![Page 18: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/18.jpg)
Sediment stabilizers: seagrasses efficiently hold
sediments in place, preventing resuspension and
movement of sediment deposits-
They reduce shoreline erosion and keep the water
clear!
![Page 19: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/19.jpg)
Seagrasses need:
• Clear water!
• Sandy or muddy bottom
• Stable salinity
• Moderate waves and currents
![Page 20: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/20.jpg)
Seagrasses are valuable and threatened compared to other major marine habitats
![Page 21: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/21.jpg)
Seagrasses evolved in a very different marine environment from today
Hydorcharitaceae
Cymodoceacea
Posidoniaceae
Zosteraceae
![Page 22: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/22.jpg)
Seagrasses evolved in a very different marine environment from today
Hydorcharitaceae
Cymodoceacea
Posidoniaceae
Zosteraceae
“An inconvenient truth” timeline
![Page 23: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/23.jpg)
Seagrasses evolved in a very different marine environment from today
Hydorcharitaceae
Cymodoceacea
Posidoniaceae
Zosteraceae
![Page 24: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/24.jpg)
Pressures to seagrass: human population
Egypt ca. 10 000 years ago
Pacific northwest, seagrass use
Washington DC, 2006
![Page 25: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/25.jpg)
Pressures to seagrass: human population
Egypt ca. 10 000 years ago
Pacific northwest, seagrass use
Washington DC, 2006
![Page 26: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/26.jpg)
Pressures to seagrass: human population
Egypt ca. 10 000 years ago
Pacific northwest, seagrass use
Washington DC, 2006
![Page 27: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/27.jpg)
Pressures to seagrass: increased invasive species
Panama Canal, 1907 Ballast pumping
Caulerpa
taxifolia
![Page 28: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/28.jpg)
Pressures to seagrass: increased invasive species
Panama Canal, 1907 Ballast pumping
Caulerpa
taxifolia
![Page 29: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/29.jpg)
Pressures to seagrass: increased nutrient input (Fertilizer and sewage)
Fertilizer applied in agriculture Fertilizer applied to lawns Wastewater Treatment Plant
![Page 30: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/30.jpg)
Fishing practices may also be changing seagrass meadows around the world
![Page 31: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/31.jpg)
Reports of seagrass losses and the rates of decline are increasing dramatically
Waycott et al. 2009 PNAS
![Page 32: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/32.jpg)
Drivers of seagrass loss
1. Water quality degradation from poor land use practices
3. Invasive species
2. Dredging and filling
![Page 33: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/33.jpg)
Research effort on seagrasses increasing, but lagging behind other coastal habitats.
![Page 34: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/34.jpg)
Within widely accessed media, reports of seagrass are lacking
![Page 35: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/35.jpg)
Bottom line: less seagrass research done AND it isn’t broadly publicized
![Page 36: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/36.jpg)
Seagrasses on a global scale
• Extensive seagrass losses have occurred in
temperate and tropical regions
• Nutrients and sediment inputs are the primary
pressures
• Research and understanding of seagrass
communities is increasing…
• BUT – despite a lot of effort, the importance
and issues of seagrass habitats are still
lagging behind other coastal communities in
effective communication to the public and
ultimately policy makers
![Page 37: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/37.jpg)
![Page 38: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/38.jpg)
A broad variety of seagrass habitats in south Florida
![Page 39: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/39.jpg)
Thalassia testudinum Turtle grass
Many (most) seagrasses are dioecious
![Page 40: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/40.jpg)
Syringodium filiforme Manatee grass
![Page 41: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/41.jpg)
Halodule wrightii Shoal grass
![Page 42: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/42.jpg)
Halophila decipiens
A monoecious seagrass
![Page 43: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/43.jpg)
Halophila engelmanni
![Page 44: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/44.jpg)
Halophila johnsonni
![Page 45: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/45.jpg)
Ruppia maritima Widgeon grass
![Page 46: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/46.jpg)
Synoptic Benthic Habitat Surveys
![Page 47: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/47.jpg)
Synoptic Surveys: Species distributions
Thalassia testudinum
Halodule wrightii Syringodium filiforme
Halophila decipiens
![Page 48: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/48.jpg)
As nutrient inputs to seagrass beds increase, species shifts occur and seagrasses get displaced by seaweeds, then by phytoplankton
![Page 49: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/49.jpg)
![Page 50: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/50.jpg)
Long-term changes in seagrass bed composition suggest nutrients are becoming more plentiful
1996 1998 2000 2002 2004 2006 2008 2010
Bra
un
Bla
nq
uet
Den
sit
y
0.0
1.0
2.0
3.0
4.0
5.0Site 273 Thalassia
SyringodiumHaloduleCalcareous Green*
1996 1998 2000 2002 2004 2006 2008 2010
Bra
un
Bla
nq
uet
Den
sit
y
0
1
2
3
4
5 Site 260
![Page 51: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/51.jpg)
Changes in relative abundance of primary producers At 19 of 30 sites, species composition has shifted in a manner
consistent with increased nutrient availability
Green: Thalassia getting denser
Red: Thalassia decreasing in relative
importance
![Page 52: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/52.jpg)
Progressive eutrophication or light reduction
Sea
gra
ss L
eaf
N:P
20
30
40
50
60
0.05 0.10 0.15 0.20 0.25
0.5
1.0
1.5
2.0
2.5
3.0
Nutr
ient-
reple
te
Oligotrophic
P-limited
Oligotrophic
N-limited
Eutrophication
Eutrophication
N:P
= 3
0:1
Leaf tissue P content (% of dry weight)
Lea
f ti
ssu
e N
con
ten
t (%
of
dry
wei
gh
t)
As nutrient inputs increase, the amounts of important plant nutrients in the seagrass leaves
changes – providing a sentinel for nutrient addition
![Page 53: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/53.jpg)
N:P of leaves
Thalassia testudinum
10 20 30 40 50 60 70 80 90 100
P-limitedN-limited
The relative importance of the two important plant nutrients nitrogen and phosphorus change across the
landscape in south Florida
![Page 54: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/54.jpg)
Some seagrass meadows in south Florida are changing in ways that indicate nutrient pollution
1996 1998 2000 2002 2004 2006 2008 2010
N:P
of T
ha
lassia
20
25
30
35
40
45
50
Site 267 Y=1032.6-0.5x
r2=0.171, p=0.002
![Page 55: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/55.jpg)
Long-term changes in N:P consistent with increases in nutrients
![Page 56: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/56.jpg)
Changes in water management in south Florida will cause a change in the distribution of seagrass species – and the animals that live in the seagrass beds
0 1 2 3 4 5
Kilometers
![Page 57: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/57.jpg)
Organic C content (% of dry wt)
0 1 2 3 4 5 6
Dep
th (
cm
)
0
50
100
150
200
250
Organic C content (% of dry wt)
0 1 2 3 4 5 6
Dep
th (
cm
)
0
50
100
150
200
250
Trout Cove
Russel Bank
Organic C content (% of dry wt)
0 1 2 3 4 5 6D
ep
th (
cm
)
0
50
100
150
200
250
Organic C content (% of dry wt)
0 1 2 3 4 5 6
Dep
th (
cm
)0
50
100
150
200
250
Nine Mile Bank
Bob Allen Keys
Corg generally
decreases
downcore in
Florida Bay
seagrass soils.
Buried peats
have high Corg
Deep, C-rich soils underlay seagrass meadows
![Page 58: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/58.jpg)
Ec
os
ys
tem
C s
tora
ge
(Mg
Co
rg h
a-1
)
0
200
400
600
800
1000
1200
**
*
**
*******
**
***
*
*
*
*
*
*
*
*
*
**
*
*
*
*
*
**
**
**
*
*
**
****
*
*
*
**********************
************
***
**
Boreal
Temepra
te
Tropic
al
Upland
Oceanic
Mangro
ve
Seagrass
Living Biomass
Soil Corg
Seagrasses store about as much C as forested ecosystems
![Page 59: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/59.jpg)
There are about 18,000 km2 of seagrass beds in south Florida
![Page 60: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/60.jpg)
A very rough estimate of carbon stored in the top meter of seagrass soils in south Florida: 18,000 km2 of seagrasses 594 tons CO2e ha-1
1 x 109 tons CO2e stored in the soils!
Anthropogenic CO2e flux is about 29 x 109 tons y-1
![Page 61: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/61.jpg)
Summary points – Seagrasses in south Florida •The Keys are home to some of the most expansive and important seagrass beds on earth
•Rapid population increases adjacent to oligotrophic marine ecosystems in south Florida may have deleterious effects on those ecosystems, as in so many other places in the world •Changes are occurring in south Florida seagrass beds that are consistent with increased nutrient availability in the system. •These changes are relatively subtle, we have not witnessed large-scale permanent loss of seagrass beds in the Keys. There is time to act!
![Page 62: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/62.jpg)
![Page 63: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/63.jpg)
Are we describing locally-
induced changes, responses to
larger-scale processes, or
natural cycles?
![Page 64: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/64.jpg)
• Sister taxa in Atlantic and Indopacific
![Page 65: The Grass is Always Greener: Seagrass Ecology in South Floridaseagrass.fiu.edu › resources › Florida Keys Cultural... · Summary points – Seagrasses in south Florida •The](https://reader033.vdocuments.us/reader033/viewer/2022060402/5f0e80737e708231d43f8dd1/html5/thumbnails/65.jpg)