Download Marine Dead Zones:

Marine
Dead
Zones:
Case Study # 2
Presented By: Blair Dudeck, September 24, 2010
Materials
Included
in
the
Reading
Package:
1. World
Resources
institute,
Aqriculture
and
‘dead
zones’”,
http://archive.wri.org/jlash/letters.cfm?ContentID=4283
accessed
Sept
22,
2010
2. NOLA.com,
“Despite
promises
to
fix
it,
the
Gulf's
dead
zone
is
growing”,
http://blog.nola.com/times‐picayune/2007/06/despite_promises_to_fix_it_the.html,
Accessed
10/20/2010
3. National
Ocean
Service,
“What
is
a
Dead
zone?”,
http://oceanservice.noaa.gov/facts/deadzone.html
Accessed
10/15/2010
4. How
Stuff
Works,
“Should
we
be
worried
about
the
dead
zone
in
the
Gulf
of
Mexico?”,
http://science.howstuffworks.com/environmental/earth/oceanography/dead‐
zone1.htm
,
Accessed
10/15/2010.
5. NOAA,
“Hypoxia
in
the
gulf
of
Mexico”,
by
Nancy
N.
Rablais,
Louisiana
Universities
Marine
Consortium,
http://www.csc.noaa.gov/products/gulfmex/html/rabalais.htm
Accessed
10/16/2010
6. Environmental
Chemistry
aglobal
perspective,
“10.2
Two‐Variable
Diagrams‐pE/pH
Diagrams”,
by
Gary
W.vanLoon,
Stephen
J.
Duffy,
2008,
7. Science
News,
“Ocean
'Dead
Zones'
Trigger
Sex
Changes
In
Fish,
Posing
Extinction
Threat”,
http://www.sciencedaily.com/releases/2006/04/060402220803.htm,
Accessed
10/17/2010
8. DAILY
NEWS,
“UBC
professor
wins
award
for
developing
phosphorus
recycling
technology”,
http://www.solidwastemag.com/issues/story.aspx?aid=1000385128,
Accessed
10/15/2010
•
•
Ecosystem
thresholds
with
hypoxia,
affects
on
biochemistry”.
Daniel
J.Conley,
Jacob
Carstensen.
Assessed
sept
15/2010
Answer
Guide
to
Environmental
Chemistry
2nd
edition,
by
Nigel
J
Bunce,
Accessed
sept
21/2010
[1]
Distribution
of
Dead
zones
across
the
globe
[2]
Table
1:
Marine
dead
zone
Definitions
Hypoxia
Anoxic
An
queues
environment
with
dissolved
oxygen
levels
in
the
range
between
1
and
30%
saturation
or
less
than
2‐3
ppm
An
aquatic
system
lacking
dissolved
oxygen
(0%
saturation)
Phosphate,
Nitrate
Major
Nutrients
[3]
What
is
a
Marine
Dead
Zone?
"Dead
zone"
is
a
more
common
term
for
hypoxia,
which
refers
to
a
reduced
level
of
oxygen
in
the
water
(crabs
killed
by
from
lack
of
oxygen
and
toxins
resulting
from
hypoxia.)
In
the
Gulf
of
Mexico
(
as
other
hypoxic
zones
the
world
over)
Less
oxygen
dissolved
in
the
water
is
often
referred
to
as
a
“dead
zone”
because
most
marine
life
either
dies,
or,
if
they
are
mobile
such
as
fish,
leave
the
area.
Habitats
that
would
normally
be
teeming
with
life
become,
essentially,
biological
deserts.
Hypoxic
zones
can
occur
naturally,
but
scientists
are
concerned
about
the
areas
created
or
enhanced
by
human
activity.
There
are
many
physical,
chemical,
and
biological
factors
that
combine
to
create
dead
zones,
but
nutrient
pollution
is
the
primary
cause
of
those
zones
created
by
humans.
Excess
nutrients
that
run
off
land
or
are
piped
as
wastewater
into
rivers
and
coasts
can
stimulate
an
overgrowth
of
algae,
which
then
sinks
and
decomposes
in
the
water.
The
decomposition
process
consumes
oxygen
and
depletes
the
supply
available
to
healthy
marine
life.
Dead
zones
occur
in
many
areas
of
the
country,
particularly
along
the
East
Coast,
the
Gulf
of
Mexico,
and
the
Great
Lakes,
but
there
is
no
part
of
the
country
or
the
world
that
is
immune.
The
second
largest
dead
zone
in
the
world
is
located
in
the
U.S.,
in
the
northern
Gulf
of
Mexico.1
[4]
Hypoxia
occurs
from
late
February
through
early
October,
nearly
continuously
from
mid‐May
through
mid‐September,
and
is
most
widespread,
persistent,
and
severe
in
June,
July,
and
August.
Hypoxic
waters
can
include
20
to
80%
of
the
lower
water
profile
between
5
and
30
m
water
depth,
and
can
extend
as
far
as
130
km
offshore.
Throughout
its
distribution,
the
impact
of
hypoxic
bottom
waters
is
exacerbated
by
the
release
of
toxic
hydrogen
sulfide
from
sediments
(Harper
et
al.,
1981,
1991).2
Basic
Chemical
Reaction:
Removal
of
dissolved
oxygen:
Bio
Mass
‐
{CH2O}
+
O2(aq)

HCO 3(aq)
+
H
Inputs
of
dissolved
oxygen:
hѵ
+
Chlorophyll

O2(aq)
↑
Mixing
of
water
e.g.
waves
[5]
Relevant
pE
vs.
pH
Graphs:
O2
(aq)
↑
+
(aq)
Dead
Zone
Formation:
Nutrients
(P,N
ect)
spread
on
field
+
sewage
Massive
Amounts
of
Biorc
Waste
Decompose
Most
of
the
dissolved
O2
used
up
in
decompsiton
Majore
Rivers
Rivers,
Streams,
Drainage
Ditches
Organism
s
which
Feed
on
Algae
Die
Hypoxia
O2(aq)
<
2‐3ppm
(eg
The
Mississippi)
seasonal
die
off
of
algi
exacerbated
Marine
life
leaves
if
it
can
or
dies
Coastal
Seas
Rises
in
Popularons
of
Higher
Organisms
(eg
Krill)
Nutrients
Consume
d
by
Alge
Massive
Algae
Blume
Marine
Dead
Zone
[6]
Major
Causes
for
the
Gulf
of
Mexico
dead
zone:
Oxygen
depletion
results
from
the
combination
of
several
physical
and
biological
processes.
In
the
Gulf
of
Mexico,
hypoxia
results
from
the
stratification
of
marine
waters
due
to
Mississippi
River
system
freshwater
inflow
and
the
decomposition
of
organic
matter
stimulated
by
Mississippi
River
nutrients.
As
a
general
rule,
the
nutrients
delivered
to
estuarine
and
coastal
systems
support
biological
productivity.
Excessive
levels
of
nutrients,
however,
can
cause
intense
biological
productivity
that
depletes
oxygen.
The
remains
of
algal
blooms
and
zooplankton
fecal
pellets
sink
to
the
lower
water
column
and
seabed.
The
rate
of
depletion
of
oxygen
during
processes
that
decompose
the
fluxed
organic
matter
exceeds
the
rate
of
production
and
resupply
from
the
surface
waters,
especially
when
waters
are
stratified.
Stratification
in
the
northern
Gulf
of
Mexico
is
most
influenced
by
salinity
differences
year‐round,
but
is
accentuated
in
the
summer
due
to
solar
warming
of
surface
waters
and
calming
winds.
Following
a
fairly
predictable
annual
cycle
beginning
in
the
spring,
oxygen
depletion
becomes
most
widespread,
persistent
and
severe
during
the
summer
months.
Other
Chemical
Effects:
As
the
concentration
of
dissolved
oxygen
drops
in
the
hypoxic
dead
zone
the
pE
also
drops
resulting
in
the
reduction
of
chemical
species
such
as
sulfate
(a
none
toxic
compound)
to
Hydrogen
sulfide
(H2S)
and
hydrosulfide
(HS‐)
which
are
highly
toxic
compounds.
The
expression
of
these
species
results
in
further
harm
to
the
ecosystem
and
the
wild
life
which
inhabit
it.
[7]
Ocean
'Dead
Zones'
Trigger
Sex
Changes
In
Fish,
Posing
Extinction
Threat:
Oxygen
depletion
in
the
world’s
oceans,
primarily
caused
by
agricultural
run‐off
and
pollution,
could
spark
the
development
of
far
more
male
fish
than
female,
thereby
threatening
some
species
with
extinction,
according
to
a
study
published
on
the
Web
site
of
the
American
Chemical
Society
journal,
Environmental
Science
&
Technology.
The
study
is
scheduled
to
appear
in
the
May
1
print
issue
of
the
journal.
The
finding,
by
Rudolf
Wu,
Ph.D.,
and
colleagues
at
the
City
University
of
Hong
Kong,
raises
new
concerns
about
vast
areas
of
the
world’s
oceans,
known
as
"dead
zones,"
that
lack
sufficient
oxygen
to
sustain
most
sea
life.
Fish
and
other
creatures
trapped
in
these
zones
often
die.
Those
that
escape
may
be
more
vulnerable
to
predators
and
other
stresses.
This
new
study,
Wu
says,
suggests
these
zones
potentially
pose
a
third
threat
to
these
species
—
an
inability
of
their
offspring
to
find
mates
and
reproduce.
The
researchers
found
that
low
levels
of
dissolved
oxygen,
also
known
as
hypoxia,
can
induce
sex
changes
in
embryonic
fish,
leading
to
an
overabundance
of
males.
As
these
predominately
male
fish
mature,
it
is
unlikely
they
will
be
able
to
reproduce
in
sufficient
numbers
to
maintain
sustainable
populations,
Wu
says.
Low
oxygen
levels
also
might
reduce
the
quantity
and
quality
of
the
eggs
produced
by
female
fish,
diminishing
their
fertility,
he
adds.
In
their
experiments,
Wu
and
his
colleagues
found
low
levels
of
dissolved
oxygen
—
less
than
2
parts
per
million
—
down‐regulated
the
activity
of
certain
genes
that
control
the
production
of
sex
hormones
and
sexual
differentiation
in
embryonic
zebra
fish.
As
a
result,
75
percent
of
the
fish
developed
male
characteristics.
In
contrast,
61
percent
of
the
zebra
fish
spawn
raised
under
normal
oxygen
conditions
—
more
than
5
parts
per
million
—
developed
into
males.
The
normal
sex
ratio
of
zebra
fish
is
about
60
percent
male
and
40
percent
female,
Wu
says.
[8]
What
is
Being
Done:
The
University
of
British
Columbia's
Dr.
Donald
S.
Mavinic,
a
world
expert
in
wastewater
treatment,
is
to
receive
one
of
Canada's
most
distinguished
innovation
awards,
the
Ernest
C.
Manning
Awards
Foundation
recently
announced.
Mavinic,
a
civil
engineering
professor
and
entrepreneur,
will
receive
the
$25,000
Dave
Mitchell
Award
of
Distinction
for
developing
a
unique
technology
to
turn
pipe‐clogging
and
polluting
phosphorus
compounds
in
wastewater
into
environmentally
friendly
fertilizer.
His
innovation
turns
a
costly
problem
into
a
valuable
product
while
addressing
major
environmental
concerns.
The
dead
zone‐inducing
phosphorus
pollution
of
natural
waters
is
one
of
the
most
significant
environmental
challenges
facing
the
planet.
Yet
phosphorus
is
also
a
dwindling
resource
that
food
crops
can't
grow
without.
Ostara's
Pearl
Nutrient
Recovery
Process
rescues
phosphorus
from
sewage
sludge,
recycling
the
would‐be
pollutant
as
the
environmentally
friendly
fertilizer,
Crystal
Green.
Mavinic
worked
out
the
chemistry
and
engineering
for
the
phosphorus
recovery
system
with
his
research
associate
Frederic
Koch
and
graduate
students
at
the
University
of
British
Columbia.
Mavinic
also
helped
spin‐off
the
technology
to
Ostara
Nutrient
Recovery
Technologies,
Inc.,
the
company
that
markets
the
Pearl
Nutrient
Recovery
Process
and
Crystal
Green
fertilizer
around
the
world.
A
single
Pearl
reactor
can
produce
more
than
500
kilograms
of
high
quality
fertilizer
per
day,
while
saving
wastewater
treatment
plants
about
$100,000
a
year
in
cleanup
costs
to
get
mineral
buildup
out
of
pipes
and
equipment.
Removing
the
phosphorus
from
wastewater
also
keeps
it
out
of
rivers,
lakes
and
oceans
where
it
can
wreak
ecological
havoc.
"Ostara's
technology
not
only
helps
to
solve
a
major
challenge
faced
by
wastewater
treatment
facilities
and
communities
around
the
world,
but
also
serves
an
important
role
in
protecting
our
natural
waterways
for
future
generations,"
says
Robert
F.
Kennedy
Jr.,
Ostara
board
member.
A
demonstration
scale
Pearl
Nutrient
Recovery
Facility
is
operating
in
Edmonton,
and
commercial
scale
Pearl
Nutrient
Recovery
Facilities
are
in
operation
at
wastewater
treatment
facilities
serving
several
cities
near
Portland,
Oregon;
as
well
as
the
region
of
Suffolk,
Virginia
and,
soon,
York,
Pennsylvania,
both
near
the
ecologically‐sensitive
Chesapeake
Bay
Watershed.
The
technology
has
been
successfully
piloted
in
several
locations
across
North
America,
Asia
and
Europe.