[Coral-List] Nutrients and algae

Thomas Goreau goreau at bestweb.net
Thu Oct 19 16:30:01 EDT 2006

Dear lovers of healthy coral reefs (as well as those who only know  
the algae and bacteria covered versions),

It's astonishing how far some people will go to deny that nutrient  
availability is the major factor limiting algae growth rates. Those  
still in doubt over this most elemental point can now look at  
film, which directly shows the impacts of modest and very localized  
sources of nutrients on algae and coral reef health. Those wanting to  
see the dirty facts for themselves can see it at:


Best wishes,

Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net

Message: 4
Date: Mon, 16 Oct 2006 21:24:24 -0400
From: "Dr. James M Cervino" <cnidaria at earthlink.net>
Subject: [Coral-List] Nutrients and Macroalgae
To: coral-list at coral.aoml.noaa.gov
Message-ID: <a0623090bc159e0a6822e@[]>
Content-Type: text/plain; charset="iso-8859-1" ; format="flowed"

Dear Alina:

Ah alas! I am finally being slapped and insulted
by Dr. Alina Szmant for"prostituting  the
literature"  and "conduct un-becoming of a
scientific officer"  eg. " This is not acceptable
scientific behavior".  All of this, because I
struck a nerve with regards to anthropogenic
nutrient inputs and algae smothering corals.  I
am somewhat disappointed by your response to my
posting. My references to nutrient enrichment
seem to have struck a nerve. In the interests of
shedding more light and less heat on this debate,
allow me to elaborate.

In my post, I referred to recent findings by
colleagues, in which they observed the effects of
macro algae on coral settlement. You correctly
point out that, in the results presented by
Kuffner et al., the presence of macrophytes was
not significantly correlated with numbers of
larvae. That paper, however, reports a large
number of significant results, including the
effect on recruit survival. The overall picture
is quite clear. If you look at my post I was
complementing a fellow coral reef scientist on a
peer reviewed newly published experiment where
they are looking at the effects of macro-algal
covering and the inhibition of coral settlement.

As far as I know p < 0.05 is statistically
significant for the macrophyte/Dictyota pulchella
or Lobophora variegata treatments and significant
difference for controls p = 0.032, D. pulchella p
< 0.0001 between tile and chamber sides! Yes, you
are correct according to the 1-way ANOVA the
presence of macrophytes did not significantly
effect total number of live larvae.  However,
recruit survival was significantly affected by
the presence of macrophytes tested during Expt. 4
(Person chi sq. P < 0.0001).

The results presented by Kuffner et al. are
troubling in their implications for the long-term
survival of coral reefs in a time of increasing
nutrient input to the oceans. There is a growing
body of evidence that this is a major problem
(Millenium Report, 2006). Your position is also
clear, as embodied in your Estuaries paper (V.
25: 743-766): nutrient enrichment is only locally
important, if that.

There is room for both points of view, on
coral-list. My (scientifically informed) opinion
is that nutrients are a major stress on reefs,
and I fear I will be shown to be correct in the
long run.

This is a valid investigation and your critique
seems to be a function of personal disagreement
with other national and international scientists
that counter your position pertaining to natural
vs anthropogenic nutrient enrichment (Millennium
Report 2006). Your position regarding
anthropogenic inputs (Szmant Estuaries Vol. 25,
No. 4b, p. 743-766 August 2002. Nutrient
Enrichment on Coral Reefs: Is It a Major Cause of
Coral Reef Decline? Is clear. You published that
"Nutrient over-enrichment is considered a major
cause of this decline because degraded coral
reefs generally exhibit a shift from high coral
cover (low algal cover) to low coral cover with
an accompanying high cover and biomass of fleshy
algae. Support for such claims is equivocal at
best". Do your studies still back this statement?

Then you say in the same paper that " Elevated
Nutrients on Coral Reefs (ENCORE experiment)
conducted on the Great Barrier Reef, does not
support the idea that the levels of nutrient
enrichment documented at
anthropogenically-enriched sites can affect the
physiology of corals in a harmful way (Szmant
2002).  But then in the following sentences you
claim that ; "Over-enrichment can be and has been
the cause of localized coral reef degradation".

Help me understand something; in the first few
sentences you are saying that enriched sites
cannot affect the physiology of corals in an
harmful way, only to see 4 sentences later that
"over enrichment has been the cause to localized
reef degradation" Therefore, which is it? Does
enrichment affect coral reefs in a negative way
and more specific; does macro-algal competition
with the host tissue negatively impair, weaken,
degrade the corals physiology?

In my post, I noted that Kuffner et al made the
point that macroalgae whose growth is stimulated
by ammonium enrichment have the ability to
inhibit coral settlement and growth. I fail to
see why this makes me guilty of prostituting the

I do understand the role of top down grazing
controlling macro-algal smothering as there were
some good experiments that showed this to have an
impact on coral survival (Lirman 2001;Coral Reefs
19). What we are saying is that the rate of
enrichment in the past 20 years cannot be
controlled by top down grazing mechanisms.

Signature algae species associated with sewage
include Chondrophycus poiteaui, Dictyota spp as
well as  L. confervoides inducing significantly
increasing mortality rates in Porites sp.
Lapointe et al., (1992) showed that ?15N values
reported for macroalgae in coastal waters with
natural and anthropogenic sources of nitrogen
enrichment indicated that the following species
are directly associated with sewage N15.  The
goal of the study was to use 15N signatures of
macroalgae and seagrass epiphytes to assess the
relative importance of anthropogenic DIN coming
from sewage in the Keys compared to regional
scale agricultural to eutrophication in coastal
waters of the FL Keys.

Corals that become smothered with cyanobacteria
(blue-green algae) Lyngbya penicilliformis are
usually associated with high sewage pollution
containing high levels phosphorous. Dense
canopies of filamentous Lyngbya, have also been
shown to displace aquatic plants in Florida
(Hauxwell et al. 2001). Measurement of stable
nitrogen isotopes (15N/14N=d15N) in biota has
been used widely to discriminate between natural
and anthropogenic nitrogen sources (Risk et al.,
2001) and could provide an early warning tracer
of anthropogenic nutrient enrichment directly
from sewage or agricultural runoff thereby
leading to the demise of tropical coral reefs
(Risk 2000).

Lapointe et al., (1990) Groundwater Inputs to
Coastal Waters [Biogeochemistry, Vol. 10, No. 3],
performed a study to determine the effects of
on-site sewage disposal systems (OSDS, septic
tanks) on the nutrient relations of limestone
groundwaters and nearshore surface waters of the
Florida Keys.  Macro-algae that were common
included species indicative of moderate or high
nutrients like Hypnea musciformis, Enteromorpha
flexuosa, Bryothamnion triquetrum, and Ulva
fasciata. (Goreau et al., 1988). Dominant
macroalgae were species that are indicative of
moderate or low nutrients, primarily Dictyota
pinnatifida, Laurencia poiteaui, Halimeda sp.,
Udotea sp,. and Penicillus sp.  (Bell 1992;
Lapointe et al.,2004; Goreau & Thacker, 1994,
Coral Reefs, sewage, and water quality standards,
Jamaica, 3:98-116).

In New England USA; Valiela et al., (1992) also
showed that human, activities on New England
coastal watersheds offer the major sources of
nutrients entering shallow coastal ecosystems.
Nutrient loadings directly from septic systems
from watersheds are the most widespread factor
that alters structure and function of receiving
aquatic ecosystems by increasing the macro-algal
biomass that dominates to such an extent that
leading to anoxic events. They found that
increases in macroalgae decreased the levels of
eelgrass habitats thereby changing the benthic
habitat leading to the significance of "BOTTOM UP
CONTROLS" in shallow coastal food webs.

In conclusion , according to the Millennium
Ecosystem Assessment Report that was comprised
of, over 1300 national science minds from the
entire globe seem to all agree that the amount of
nitrogen and phosphorus that has been released
into the environment as a result of using farm
fertilizers and sewage has doubled since the 80s
and that the level if nutrients being added into
the marine ecosystem cannot be controlled by
adding more grazers into the system.  According
to the report; The sudden and extraordinary
release of anthropogenic free nitrogen and
phosphorus - has triggered massive blooms of
macro-algae in the freshwater and marine
ecosystems. According to the top minds on the
planet that understand nutrient gradients along a
macro-algal profiles identified that the nutrient
loading problem has pushed the planet to the
"tipping point" that can suddenly destroy entire

Please keep the personal insults off the list, in
the future contact me directly- James

Hi Jamie et al:

I do not understand your comment about the Kuffner et al 2006 paper.
For one there is no mention of any nutrient effects of any kind.  Thus
the patterns of algal distribution and biomass that these authors report
are what are found out there but there are no data to show that they
have anything to do with nutrient (or grazing) levels.  The areas they
surveyed are directly offshore of where Florida Bay water exits onto the
Florida reef tract and are best characterized as hard bottom.  There has
been little coral and lots of sediment on those hard bottom over
Holocene time frames (reviewed by Ginsburg, Shinn and others)

Secondly, if you read the paper carefully and study the figures, their
results show that some (not all) algae have a small but variable effect
on coral settlement.  In some cases there was more settlement in
treatments with the algae, in some not, thus not a strong indictment of
algal inhibition of coral settlement. Furthermore, while some of the
differences between treatments were statistically significant the
differences were not biologically/ecologically significant given natural
variability in coral settlement patterns.  My work has shown a strong
preference of several species of coral larvae for the undersides of
field conditioned substrates (Szmant and Miller 2006, 10th Coral Reef
Proc) regardless of presence of macroalgae. In fact, larvae avoid
surfaces covered by algae, encrusting inverts, and some types of
crustose corallines too.  They mostly settle on microfilm and there is
plenty of that available at the scale of a coral larva, even when
macroalgal cover is high.

The likely negative effect of macroalgal cover on coral recruits likely
shows up later when the corals grow out of their cryptic settlement

I know that excess nutrient enrichment, as well as too little grazing,
as well as too much grazing, can all damage small corals, affect reef
substrate composition etc etc etc.  But I hate to see the literature
misquoted for any reason, and your post is a perfect example of how easy
it is for scientists to prostitute the literature.  This is not
acceptable scientific behavior and should be avoided even if the
intention is laudable (e.g. to deter people from polluting coastal


Dear Ilsa & Devon,

Congrats on a thorough well put together manuscript! It is about time
that these data are beginning to get published, I will use this for
my class this next semester.

The sad point is that the people that think urchin grazing and other
dwindling herbivores/landscapers swimming on reef system control the
algal lawns that smother corals.  This says to the developers that
claim  "hey our point source" that is spewing secondary treated
sewage out into a reef is not the reason for the reefs to become
algal dominated, its because the spiny urchin died off that used to
be a proficient landscaper and kept the corals "macro-algae free".

Devon what I am not saying that top down controls are not
significant, they are. However, what I am trying to say is that the
levels of nutrients that induce algal blooms cannot be controlled
with more grazers.

Cheers, James

Dr. James M. Cervino, MS, Ph.D.
Marine Pathology
Department of Biological & Health Sciences
Pace University New York NYC
Phone: (917) 620-5287
Web site: http://www.globalcoral.org


Message: 5
Date: Tue, 17 Oct 2006 07:03:46 -0400
From: "Jim Hendee" <Jim.Hendee at noaa.gov>
Subject: [Coral-List] Global Heat on Coral-List
To: Coral-List Subscribers <coral-list at coral.aoml.noaa.gov>
Message-ID: <4534B892.6080904 at noaa.gov>
Content-Type: text/plain; charset=ISO-8859-1

Esteemed Subscribers...

     I just released from the coral-list queue James Cervino's response
to Alina Szmant via Mike Risk's comment.  Please note that although
Alina didn't actually call anybody a name, the words were obviously
charged enough to elicit the barely contained seething responses.  As
I've mentioned before, the listserver software does not allow me to see
all of a message unless it looks suspect to me and I forward it to
myself so I can read it in its entirety before letting it go.  Sometimes
the top of the message seems harmless enough, though, so I let it go,
which is what happened in this case.  I must confess that I do not read
every single coral-list message in its entirety; and I must also confess
that I do not read to completely to understand the content of each
message (wish I could; but alas, the time...).  Sometimes I feel like Ye
Olde Boston Book Reviewer, scanning to find the porn or the dirty words.

     At any rate, I would ask that if anybody is impugning anybody's
professional integrity, could you please take it off-line?  This subject
of nutrients and coral health has been one of interest to me ever since
I saw Jim Porter's presentation at the NCRI conference years ago when he
found--in that particular case--that nutrient enrichment in the area of
the Florida Keys he studied appeared to actually be conducive to coral
growth [I hope I've remembered this correctly, Jim!].

     So, have at it, Team, but please BE NICE!


Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net

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