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Problems for the Present and
Future Ocean
A. Ocean acidificationB. Coral BleachingC. ExtinctionsD. Invasive Species E. Phytoplankton Production DownF. Harmful Algal bloomsG. Dead ZonesH. PollutionI. Habitat destructionJ. Sustainable Fisheries
E. Decrease in primary production?
- primary production down over last 20 years
especially in areas where temperature has risen the most between early 1980s and late 1990sPP decrease
9% North Pacific~ 7% in North Atlanticoverall ~ 6 % NOT SURE WHY THIS JUST CORELLATION
F. Harmful Algal Blooms (HABs)
formerly called Red Tides
red tide
HAB -phytoplankton concentrationshigh enough to harm the environmentand organisms.Phytoplankton from different groups(diatoms, dinoflagellates, etc.) mayform HABs.Red or brown tides are HABs causedby phytoplankton that colors thewater.
Estimated costs of HABs in USA Public health (poisoning): $20 mill. year-1Commercial fishery: $20 mill. year-1Tourism: $ 7 mill. year-1Management: 2 mill. year-
How HABs can negatively impact their environment
Produce toxins that can cause paralysis, amnesia, or intestinal problems
- Resulting secondary bacterial blooms can cause anoxia and hypoxia, killing
fish and any other local oxygen requiring organisms.
- Produce such a large biomass that shades the organisms below, depriving
them of heat and light.
Out competes other phytoplankton and thus reduce the availability of algae food
The production of large amounts of mucous, which
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sinks smothering organisms on the benthos
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when accumulating on beaches harms tourism
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clogs fishing nets
There are NO known antidotes for poisoning caused by HAB toxins
!
Types of poisoning: 1) Paralytic Shellfish Poisoning
(PSP)
http://www.whoi.edu/redtide/illness/asp.html
Saxitoxin
Dinoflagellates:Alexandrium sp.
Gymnodinium catenatum
Akashiwo sanguinea
Lingulodium polyedrum Common in the SB channel, producesbioluminescence
Types of poisoning: 2)
Diarrhetic poisoning
Dinophysis acuta fromSB Channel
Domoic Acid
http://www.whoi.edu/redtide/illness/asp.html
Types of Poisons: 3)Amnesic Shellfish Poisoning (ASP)
Pseudo-nitzschia sp.
Diatom- Pseudo-nitzchia australis,^ Another common channel HAB species.
Different species ofpsuedo-nitzcheaProducing domoic acidtoxins during a largebloom along the westcoast in 1998.
HAB species can take advantage of many differentnitrogen sources •^
The nitrogen source (among other factors) can ultimately determine which species will dominate. •^
Psuedo-nitzchea
prefers urea which has become a major
component of commercial fertilizers. Bacteria necessary for Domoic acid (2 to 115 times moredomoic acid in presence of bacteria)
G. Dead Zones
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Anoxic conditions on the ocean bottom covering large areas.
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Caused by eutrophication-enhanced algal blooms
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Chemical fertilizer is the prime cause of dead zones worldwide.
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Where: 405 dead zones worldwide^ Natural
: some fjords, northern Indian Ocean
Human Caused
: Examples
1. Black Sea- Disappeared from 1991-2001when fertilizer use stopped. Largest in world2. Coastal waters of South America, China, Japan, and
southeast Australia.
3. Oregon - Off Cape Perpetua -
1120 square mile
(2900 km²) between June and September every year since 2002.
- Gulf of Mexico Dead Zone -^
22,126 square kilometers (8,543 mi²) near the mouth of theMississippi. Equivalent to the size of New Jersey
Temperature
Oxygen - yellow and red
=anoxic and very low
Size changes seasonally
- Gulf of Mexico Dead Zone
Impacts:
1. Benthos supports only bacteria.2. Massive fish and shrimp kills
72% of U.S. harvested shrimp,66% of harvested oysters, and16% of commercial fish
Solutions
1. Use fewer fertilizers2. Adjusting timing of applications to crops3. Keep animal wastes out of waterways4. Monitor sewage treatment5. Limit industrial sources of nutrients6. Restore wetlands
H. Marine pollution - Oil
Big spills
Routine maintenance
Down the drain
Up in smoke Offshore drilling
Natural seeps
0
50
100
150
200
250
300
350
400
1 2 3 4 5 6
Million of Gallons
Impacts
Lethal for some organisms, oiled animalsAccumulation up food chain- fish develop reproductive and liver problemsReduces diversityLong term, chronic pollution - may last 50 or more years, accumulates in sediments
Marine pollution- other major toxic materials
many accumulate up the food web
•^
Hg - (air pollution, manufacturing) birth defects, nervous sys. damage
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Dioxin (pesticide and paper manufacture), causes genetic aberration,very toxic
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PCB's (hydraulic fluids) developmental problems
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Other heavy metals - Cd, Pb (manufacturing)- toxic
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Tributyl Tin - (antifouling paint on boats) highly toxic
-^
Plastics
-^
Raw Sewage- eutrophication
London Convention - regulates and bans dumpingLaw of the Sea (1994)- governs sea-bed mining,
environmental protection, and exploitation of naturalresources
I. Habitat Destruction
1. Bottom Trawling
http://marinebio.org/Oceans/Conservation/HabitatConservation.asp
2. Estuaries-
shellfish beds, sea grass meadows, salt and fresh
marshes, forested wetlands, beaches, river deltas, and rocky shores.highly productive104 Estuaries in USImportant nursery grounds for fishHigh commercial value - 111 billion $ annually
Wetland Destruction
•^
Puget Sound
- 73% of the original salt marshes have been destroyed;
•^
Narragansett Bay
- 50% of salt marshes filled;
•^
San Francisco Bay
- 95% of its original wetlands destroyed
•^
Galveston Bay
- 85% of seagrass meadows gone
•^
Louisiana estuaries
- continue to lose 25,000 acres annually of coastal
marshes, roughly the size of Washington, DC;
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Hudson-Raritan Estuary
- 75% of the original tidal marshes gone
•^
Chesapeake Bay
- 90% of seagrass meadows were destroyed by 1990; in
30 years (1959-89), oyster harvest fell from 25 million pounds to 1million;
-^
Long Island Sound
- More than 40% of the tidal wetlands destroyed
•^
North Carolina Estuaries
- lost more wetlands than any other state from
1973 to 1983; and
-^
Tampa Bay
- 80% of seagrass meadows destroyed.
the loss in each estuary is an accumulation of small development and other projects
