2023-09-29-SAC Meeting Summary

NC Nutrient Criteria Development Plan – Scientific Advisory Council (SAC)

9/29/2023

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Attendees
SAC members in attendance:
Hans Paerl (SAC Co-Chair)
Jud Kenworthy (SAC Co-
Chair)
Jessie Jarvis
Martin Lebo
Lauren Petter
Michael O’Driscoll
Fritz Rohde
Wilson Laney

NCDEQ staff in attendance: Note: may not have captured all DEQ staff in attendance
Elizabeth Liebig
Cam McNutt
Susie Meadows (note taker)
Pam Behm
Karen Higgins
Anne Deaton
Charlie Deaton
Timothy Ellis
Nora Deamer
Heather Jennings
Mark Vander Borgh
Bongghi Hong
Amir Adaryani
Elizabeth Fensin
Others: Nathan Hall (UNC), Anne Coan, Clifton Bell, TJ Lynch, Andy McDaniels, Doug Durbin,
Paul Cough
SAC meeting facilitator: Karen Higgins (NCDEQ)

Meeting notes
***All questions, comments and answers are paraphrased***
1) Convene (Elizabeth Liebig)
• SAC introductions only in the interest of time.
2) Recap of the SAC Charter (Elizabeth Liebig):
• Appointments for this SAC were made on June 27th, 2022, and they are two-year
appointments, which means that the current terms expire on June 26, 2024. So,
we have a limited amount of time together to address all these remaining issues.
So, including this meeting, there are 5 remaining meetings through May of 2024.
• Our desire is to have specific topics and questions for discussion at each meeting,
and we can branch off as needed from there. These topics and questions will be
distributed three to four weeks prior to the next meeting and will be based on the
previous SAC discussions and this will give the SAC members time to prepare and
be ready to discuss these questions during the upcoming meeting. We would also
desire that these meetings be outcome based.
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• We mentioned in the July meeting the idea of beginning with the end in mind, so
we'd like to focus on decision making and documentation of these topics.
So, for example, based on chlorophyll a, we can see a white paper being developed
which would document the conclusions and provide scientific justification on any
decisions made.
• This fall, we would like to focus the discussion on chlorophyll a, which was brought
up at the last meeting in July and we would like to accomplish 2 things:
1. Examine the chlorophyll a standard and see if it is protective for SC
waters and
2. Determine the chlorophyll a relationship to nitrogen and
phosphorus.
• We’d like to spend 2 meetings on this topic. Today's meeting and in November,
but then over the winter we would like to discuss and focus on harmful algal
blooms and cyanotoxins, and we'll spend 2 meetings on this topic as well, in
January and March of 2024.
• In May of 2024, we would like to finalize and have consensus votes on the white
paper and for the SAC to provide future recommendations.
• So, this is an outline of where we would see the remaining meetings going. Are
there any questions, comments, or thoughts on this approach?
• Karen: Silence is consensus.
• Hans: Down the line SAC may have presentations on topics, is that ok?
• Elizabeth: Yes, definitely. We would like to extend the meetings back to the
original 3 hours, from 1-4 pm.
• Karen: We’d like to vote on the minutes, but Libby is going to check that having 8
members is enough to vote. We have a few members that need to leave at 2 pm,
so we are going to adjust our schedule.

3) A few words from Hans Paerl:
• I'm just going to say a couple of things. We know an awful lot about chlorophyll in
terms of the various systems that we're going to be talking about, including
Albemarle. And chlorophyll is one of the obvious optical components in terms of
transparency and lastly, chlorophyll is something we can maybe do something
about in terms of controlling it or at least mitigate or reducing it in terms of
nutrient reductions, particularly nitrogen.
• And there's pretty good data and evidence that there is a strong relationship
between nitrogen inputs into our rivers, particularly downstream going into our
estuarine ecosystems, which tend to be nitrogen limited.
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• I'm very interested in mining the chlorophyll data and the chlorophyll evidence
that we have, particularly in relation to optical transparency of the system going
back to the SAV issue in question. And secondly, what evidence is there, that there
is a pretty strong link between nitrogen inputs into our estuaries and chlorophyll
as a component. Lots of us measure chlorophyll in different ways, and that's
probably another issue to briefly discuss.
• The linkage of fluorescence measurements of chlorophyll versus the extracted
chlorophyll values. And I know there are some differences that are probably worth
discussing as well, but that's kind of a second order thing.
• I’d like to give Nathan the floor.
4) Nathan Hall’s Introductory and Comments:
• So, question #2 is the one that I feel the most prepared to answer now with the
biological model results. I’ve shown previously that for the high salinity, the SAVs,
the current chlorophyll-a standard with the way that it's assessed, it's not
protective of the clarity we need for seagrasses.
• I've recalibrated the model and the model is working great now for low salinities
and it's pretty much the same answer. The 40 μg/L assessed at the 90th quantile
ends up giving you a median chlorophyll-a of about 20 μg/L. And we need that to
be somewhere around a median of about 10 μg/L in low salinity waters, given the
current levels of turbidity and CDOM. Those numbers were really similar between
the high and low salinities.
• If we want the water clarity to be what we've said, which is, 22% to 1.7 meters and
13% to 1 1/2 meters low salinity, keeping our CDOM and turbidity the same, we're
going to have to have a median chlorophyll below 10. That’s the answer.
• Hans: Have you divvied up the turbidity and CDOM?
• Nathan: Currently the median chlorophyll is right at 10. If you look across all of the
low salinity waters, it's higher in some areas, lower in other areas. But across all
the data it's around 10. I haven’t partitioned it yet; still working on it. That’s going
to be very region specific.
• Martin: What is the relative contribution of the chlorophyll versus the turbidity
and CDOM?
• Nathan: I haven't done that partitioning yet. But it's going to be very region
specific. In certain areas the turbidity is going to be more important, in certain
areas the chlorophyll maybe, I'm not sure. CDOM is definitely going to be more
important in some areas.
• Martin: Because that is going to be an important factor that feeds into whether
chlorophyll needs to go down or what level it needs to go down.
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• Jud: Nathan do you have any feeling at the moment how much subdividing might
have to be done to adapt that variation to a feasible standard?
• Nathan: Not right this second, no. The CDOM is naturally occurring we don't have
control over it yet. And so far, the thought has been that we'll take care of that by
saying this only applies to areas that we have previous seagrass or SAV. And that’s
been the plan as this process has gone forward. But the issue is that map has no
bathymetry associated with it, and now we're trying to work with bathymetry into
this concept behind these standards. But our map that's supposed to say where
this applies doesn't have any bathymetry associated with it, so that's the
disconnect. I don't know exactly how to deal with that.
• Jud: Related to that topic of bathymetry. The Albemarle Sound has been a target
pilot spot for us, which is only just low salinity, there is a very large project going
on in Albemarle Sound, funded by NOAA to create a very precise bathymetry map
of the entire sound and that project’s being done by Geodynamics. Which is now
been assimilated by a much larger company. But we don't have the bathymetry
data we need for the low salinity at the kind of resolution, but we'll have to work
with what we got. So, has anyone got a feel for what it might take to move the
needle from 40 to 10?
• Nathan: You're not moving the needle from 40 to 10, though. As far as the
standard goes. Because the median chlorophyll out there is about 10. In certain
areas it’s higher than 10, but on average we're close to that 10 for most of the
water that we're talking about. So, we're not talking about moving the needle
from 40 to 10 as far as what's in the water we're talking about translating from a
do not exceed 40, with that 10% allowance, to a median of 10.
• Wilson: Going back to Jud mentioning NOAA creating a more precise map, what’s
the precision?
• Jud: pretty precise because of the technology their using, multibeam sonar side
scan. They're using the same technology they do to measure bathymetry and the
channels and beachfronts and everything.
• Wilson: That’s great. Given that our Sounds are so dynamic, especially after storm
events, would the maps have to be revisited? The Albemarle is generally shallower
than Pamlico. How long would you expect a bathymetric map to last? How stable
would this system be?
• Hans: I think we're going to have to see what the results of the analysis are by the
folks doing the assessment, right. I mean, they're not just measuring it at one time,
it's over some set of the intervals?
• Jud: I don't really know what their survey plan is. It's a big water body, but I guess
in response to Wilson's comment, I think Albemarle Sound would be more stable
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than Eastern Pamlico Sound or others. So, what we're going to have is a product
that's much better than what we've ever worked with. As I understand it, NOAA
has this huge long-term program to update all the bathymetric information in our
coastal waters nationwide. I guess they're picking and choosing water bodies? I
don't know what the criteria are or how they decide that, but I would say those
dynamics would be a lot greater in the high salinity environments that are subject
to inlets and big wave fetches and large sediment sources.
• Hans: Nathan, if I could go back to your statements. If I'm going to interpret the
chlorophyll stuff, in a kind of a practical way, what you're saying is that it doesn't
matter a whole lot whether it's 40 or 10, because the impact that chlorophyll has
in terms of its component of the attenuation of light in the water column is pretty
small to begin with. Is that right?
• Nathan: I didn't say that, in some areas that's really important.
• Hans: But it would only be important in systems that have no turbidity or very low
turbidity.
• Nathan: No, I mean in the Neuse River, you've got almost an even split between
CDOM, chlorophyll and turbidity on average contributing to attenuation. Certainly,
in the more CDOM rich water, CDOM is probably going to be in a more important
fraction than turbidity and chlorophyll. But chlorophyll can still play an important
role.
• Hans: The issue with chlorophyll, is it really more closely related to issues of excess
production and harmful algal blooms than the SAV question overall, but I guess to
know this we need to know what those components are in different places and
also whether or not those places are susceptible to algal blooms and other water
quality impacts.
• Mike: Nathan, what do you think as far as seasonality, are you referring to an
annual median?
• Nathan: Yeah, all the data, they are monthly data looking across all the seasons.
• Mike: I'm just curious in the patterns, if it's really low in the dormant season and
then it is it very variable, like more issues in the summer and later fall? I wonder if
it's good to also focus on that season where we could get real extremes you know?
• Nathan: All 3 of the different things that contribute to attenuation have their own
kind of seasonality. CDOM goes up during the summer and fall. Chlorophyll,
depending on where you're at, can go up during the summer. Turbidity goes down
in the winter, so yeah, they all seem to have their own seasonality.
• Mike: That’s great you can see the need towards the 10 μg/L. And then if there's
conditions where it does get really, really low, during the winter then does it allow
it to get higher to get towards that? If there's that kind of issue where just kind of
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being protective of extreme problems in the summer, I wonder if looking at that
part too might help us out, you know?
• Nathan: That’s a good point. I could redo the analysis I did with just the growing
season data, and that would get around that, balancing by the winter data,
especially for the lower salinity areas probably does have lower chlorophyll during
the winter.
• Jud: It seems like the criteria for chlorophyll should be coordinated with what we
said for the clarity standard otherwise there would be a significant disconnect
there.
• Hans: Well, I know we go through this clear water phase in the wintertime with
regard to chlorophyll, which is pretty much a light limitation and then it can kick in
pretty early, right with spring blooms. We’ve had some pretty profound spring
blooms in our rivers going into the sounds.
• Nathan: Yeah, I mean, January and February are often the highest chlorophyll
concentrations.
• Hans: So, Mike's points really good because I think the seasonality is a huge issue.
• Martin: I was following-up on the seasonality that it depends on where you're
looking. Often the winter has the larger flow events, which may increase turbidity
depending on the nature of the storm, but also moves your chlorophyll peak down
as far in the Neuse to like Oriental. So, there is an interaction, not the same space.
• Hans: That gets pretty complicated. You’ve got the seasonality issue and then
you’ve got the drivers that are moving the chlorophyll max around and in relation
to other optically active components including CDOM. Well, again, I think the real
question here is, does it really make a difference? I think that's kind of the bottom
line there with regard to chlorophyll, the role that chlorophyll plays in attenuation.
• Karen: So, there's a few SAC members we haven't heard too much about on this
topic.
• Lauren: I'll just agree that I think looking at the seasonal component is good just to
make sure whether it's going to make sense to have a recommendation that's an
annual chlorophyll or something different.
• Martin: My main thoughts are we need to balance between how we achieve sort
of clarity that it it's not all about chlorophyll reduction. It's got to be a balance
between the different components. The CDOM may not, in many systems, be
something that can be touched if it's sort of a drainage from floodplain areas.
• Lauren: And I think, Nathan, you were thinking that hopefully where the CDOM is
the most impactful was potentially or should be overlaid where there's not
seagrass to be expected. So hopefully that's part of the case, but I think you
mentioned that there's still some partitioning to kind of quantify. So, I think that
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just proves what we think could be happening. So, that seems like that's just one
of those things to document what we conclude or able to prove this is happening,
based on the modeling and what we know.
• Nathan: So, I just reran the model to look at those, chlorophyll and turbidity
values, that would give you the low salinity, clarity target. March through October.
Chlorophyll value of 9 and turbidity value of 3.
• Lauren: So does that make sense to folks that if we're looking at it for the growing
season, that SAV is showing similar results, do people think we need to include the
whole year to be more comprehensive or something based on
contributions/impacts? It looks like they’re all pretty similar values.
• Nathan: I should probably look at different regions.
• Pam: It seems like right now chlorophyll-a data is collected midchannel. It doesn't
seem like that's where clarity is going to be targeted towards. So is this a separate
thing? Are they together? I can see some connection between the two, but do
they have to coexist as like a group standard or something like that, because it
seems like you're sort of targeting separate issues? Are we just talking about
chlorophyll here in connection to implementing the clarity standard, or is this a
broader topic?
• Jud: It would seem to me that we have to line those up. If the goal is to manage
chlorophyll to get to a water clarity standard to protect SAV they should be
collected in the same locations.
• Pam: I was thinking that this was sort of looking at those big algae blooms and that
this was going to be more than just targeting the SAV growth.
• Hans: There’s an additional issue with the algal blooms and that’s that they’re
often not in the same place and depending on the wind, they could pile up on one
side of the estuary. That would have a huge effect because you know the blooms
can be pretty dense once they get concentrated on one side of the estuary. So I
think the variability there is going to be tremendous. But the amount of
chlorophyll on one side of the river or estuary can be multiple times what it is on
the other depending on wind and accumulation of biomass.
• Cam: The way that the standard is worded right now, it has pretty specific spatial
component to it, which is historic and existing SAV and it has all the list of species
and everything versus the chlorophyll-a standard is protective of aquatic life,
which could include mid channel fish populations. So, for the SAV areas are we
monitoring clarity as it impacts the SAV? I think the answer is yes. And then after
that, we're looking at evaluating, based on what Nathan said, it's going to be
variable. Whether it's a lot of chlorophyll and sometimes a lot of turbidity, and
we'll have to make that decision on the site-specific basis as relates to clarity, but
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we may not have to address a chlorophyll-a standard necessarily. We just have to
find out what that median value is to protect the clarity standard and then go after
N and P in some sort of reduction strategy, whatever that looks like in the same for
turbidity. And then CDOM is impacting as part of that, then we need to determine
if the CDOM component is due to natural conditions, or do we have an extensive
ditch network that's dumping into this area. So, I think the SAV clarity component,
all of those considerations are done on the solution side rather than on the
standard side versus the chlorophyll-a on its own that covers all SC classified
waters. Need to be looking at algal blooms in the wider sense, and not just as it's
compared to clarity. That may have been too much, but I've been thinking about
this for quite a while now.
• Hans: I would agree with you on that, Cam. On the latter point, there.
• Lauren: I just want to clarify, is the thought that we're going to figure out what the
chlorophyll number is that's needed to protect clarity and not make it a chlorophyl
standard that applies. You would use it to come up with an N and P to meet that
chlorophyll and the N and P would be the criteria endpoint. Is that what you were
saying, Cam?
• Cam: Well, and N and P potentially the criteria endpoint or a TMDL. I keep running
it back into a TMDL type of thing, especially if it's going to be variable across the
low salinity seascape, and then variable against the highest salinity seascape. And
then the chlorophyll itself, that's the aquatic life in general, not just protecting the
clarity that may need to be addressed differently. That applies to all waters versus
just where… the issue is really the clarity standard is targeted at a very specific
kind of smallish area compared to the larger sounds and that was one of the
questions that I had in the next part of that is how do we decide what that is and
do we group them in areas and say we take the lowest one and work from there,
but that may be different from what's happening in the Chowan River where SAV
is not a consideration but harmful algal blooms are. And I don't know if, those two
numbers come together, especially if you're going to look at it potentially in terms
of how it impacts recreation, swimming by humans, not just aquatic life, which
from what we're hearing, the concerns if in that area are not about protecting
aquatic resource, this is about protecting recreational resources.
• Hans: Agreed.
• Lauren: And so, I don't know if we'll get into more of that in the January, March
meetings when we talk about HABs and cyanotoxins. As I'm kind of hearing folks
talk about it. I understand why the chlorophyll based on SAV protection is a very
targeted location-specific protection, but it's something that applies in that
waterbody. I guess what we'll finish talking about is those other uses, whether the
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40 is still the right number for those recreation uses when we talk about HABs and
cyanotoxins, is that what you're thinking?
• Cam: That’s what I'm thinking. Like Nathan said, if you had a target median of 9 for
chlorophyll-a, that's for the clarity standard. So, that may not be the number that
we're looking for in the Chowan River. That's 40 miles upstream of the nearest
SAV.
• Lauren: I think that makes sense that we're going through kind of checks the
different uses. I guess it all depends on how we proceed with what we do with that
chlorophyll of 9 or 10 or whatever, because when you have multiple uses, you
could have the 9/10 that protects the SAV. I'm just making up a number. What if
it's 13 to protect HABs? And so in the end, you've got a water body that has 9 and
a subset of the water has a 13, in the rest of the waters, …does the 13 only apply
where there's not SAV? I don't want to completely, like, drop it from criteria
consideration, but I understand like it's sort of like pending future conversation, I
guess is what I want to say because it could be that you have different regions of
the sound that are protected differently and you sample for the mid channel water
like you're currently doing for whatever some future number could be for
recreation use. But maybe you're also looking at the chlorophyll at the seagrass
areas, or you're looking at the N and P or whatever the future thing is. So, I don't
think we know yet. It all just depends. Or does it go down a TMDL route and none
of the chlorophyll, it has the potential to have competing chlorophylls to be
applying or not?
• Cam: And that's kind of a spatial judgment issue where if they're in the same
general vicinity, you would take the lowest one and then you would be protecting
the other one. The thing that I'm running into is that the SAV, as the map does not
extend in some places where we're applying chlorophyll-a and that's where we
could run into some pushback. Because the clarity standard is specific.
• Martin: Yeah, it's sort of another complication. I mean the uses that have
discussed so far are all pushing it lower, chlorophyll being better and there’s a lot
of effort that has been expended over decades trying to recover fisheries in the
rivers into the Albemarle Sound and pushing chlorophyll too low would also
potentially impact the capacity of the system for fisheries.
• Hans: That's kind of a damned if you do, damned if you don't kind of point I think
because you know we've got issues like toxicity for example that can occur at quite
low chlorophyll levels or really high levels, it's highly variable the toxicity. That’s
one thing we've seen so far from looking at toxin analysis of these blooms.
Sometimes the blooms can be humongous with low toxicity and other times they
can be near 10 and have significant toxicity. There’s a huge variability there.
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• Martin: I just wanted to make sure, there's an ensemble of uses and they're not all
protected by low numbers. So, somewhere in the middle trying to maximize
production is probably where the answer is that really benefits the system the
most.
• Lauren: So hopefully we can capture all the different areas where certain
chlorophylls would be protective and then look at that holistically once you have
all that figured out, because if they're all close, then you make some judgment
calls on average or you know different things like that or if they're more separate.
Is it a regional solution?
• Hans: Well, the other thing is that we have a pretty good idea on who the good
players and the bad players are, whether it be from a recreational protection,
things like that, or fisheries. I think really what we want to manage is to reduce the
frequency and the extent of the harmful, and by that I mean largely cyanobacterial
blooms, in these systems. So, you know that should be the target overall in the
system because, from a fisheries perspective, the cyanobacteria that caused the
major problems are also a negative factor for fisheries in most cases. The
cyanobacteria that are probably most beneficial for fisheries are the smaller guys
that support zooplankton and a healthier food web. So, I think the target should be
the bad guys, the notorious sort of bloom formers that we see in the system. And
those could be targeted from both a human use perspective, recreational etc, and
also from a fisheries perspective.
Nathan, do you agree with that? Oh, Nathan probably left. OK. Well, I think Nathan
would agree with that even though I'm speaking for him, but there are a lot of
small cyanobacteria in the system that are probably beneficial from the food web
perspective because they're supporting zooplankton and intermediate levels of the
food web and they're not the notorious bad guys that we see going back up in the
rivers. So, I think those should be the targets really. I mean certainly from a human
use and environmental health perspective and if we target those then we're also
probably having a beneficial impact on fisheries resources. Cam do you, would you
agree with that?
• Cam: I just keep writing down optimization, so I'm thinking, weighing everything
out and locating it in space and the sounds I think is going to be important too.
And there's a lot of economic drivers attached to all of these considerations.
• Hans: From just a chlorophyll partitioning perspective, just to give you some idea, I
think with some of the size fractionation work we've done on the Albemarle and it
hasn't been very much, but there has been some, the small stuff accounts for quite
a high percentage of the total chlorophyll based biomass in the system. So, I'm not
so concerned that we're going to have a negative impact on fisheries by mainly
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targeting the big guys, even though they're very obvious in the system, they
generally don't account for a huge amount of the biomass, maybe, during a bloom,
maybe 30% or so. So, I guess what I'm saying in response to Marty's comment is
that I think we can be on the safe side for targeting the big guys that are causing
the problems without necessarily having to have a negative effect on fisheries.
• Martin: The one comment I'll make in response is it may be challenging of how we
target and what we actually use as the tools. Chlorophyll may not be the ideal
target in terms of how to control the bad guys that are the main ones we don’t
want in the system.
• Hans: Well, on the other hand, if we start reducing nitrogen, I think that the big
guys will be affected most. The big guys, and by that I mean, the filamentous
cyanobacteria and Microcystins and stuff like that, will be more directly impacted
because the small, the picoplankton that are out there, presumably the good guys,
they are really good at using regenerated nitrogen and they kind of run like a
Toyota as opposed to the big guys running like a Cadillac. So, I think by imposing
nutrient reductions or nitrogen reductions will probably have a more profound
effect on reducing the large component size wise, which are the problematic
organisms in the system. And that's just because small cells are more efficient at
taking up nutrients, including nitrogen, which appears to be the limiting nutrient
out there, and they can subsist on regenerated nitrogen in the system.
• Martin: So, Hans, any thoughts on whether sensually controlling nitrogen may flip
some of them to fixation?
• Hans: Well, I think we have looked at that question and it turns out that nitrogen
fixation generally, is not the dominant new source of nitrogen. During the summer
period, it still really comes down to external loads and regenerated nitrogen. So, I
think we can be on the safe side by starting to reduce nitrogen inputs without
having to worry too much about all of a sudden stimulating huge nitrogen fixing
blooms. Although that's a good question.
• Martin: It's just like it's one among the whole handful of complications on getting
to the end of this.
• Hans: When we have had nitrogen reductions in systems, and I'm thinking about
some of the European waters and the Chinese stuff that we've been working on,
typically the bad guys which would be the guys that require nitrogen are going to
be impacted more severely or reduced more severely that the issue with nitrogen
fixation isn't just a matter of how much nitrogen is there but also their energy
requirements for fixing nitrogen in optically challenging waters like some of the
ones we have. They just don't get enough light to fix nitrogen or the nitrogen
fixation rates are quite low.
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• Wilson: Maybe going off on a wild tangent here, Hans, but I wondered if you know
what difference it made that historically the Chowan Albemarle system had these
immense shoals of filter feeders. And I don't know whether we need to think
about this much at all. But those populations in that system are at historical
minima now, so they're really a whole lot less than they were historically. And I
wonder how much that might be a contributing factor to the problem of the
harmful algal blooms to begin with? I don't know that anybody's looked very
closely at what they're filtering out, which phytoplankton are they targeting? Do
you have any information on that?
• Hans: Well, again, I think if you go to the limnological literature for this, there have
been studies looking at what you're talking about, the potential for top-down
effects, right? Grazing effects.
• Wilson: Yeah, exactly.
• Hans: I think if you look at systems that have had some studies like that, it doesn't
seem to be a very important component of what's controlling the blooms, in large
part because the blooms tend to be very episodic in terms of when they come on
and when they crash or die, and they generally don't crash because they're getting
grazed down, they crash because of some physical factor changing in the system.
Like it gets cold or there's mixing going on or the residence time changes. With
caution I would say that top-down grazing effects have probably not had a major
impact on the bloom dynamics in that system.
• Wilson: Ok, thanks.
• Hans: And I can if you guys like, I can do some digging up there on the literature to
substantiate that.
• Wilson: And the other thing, that we've already talked about, the seasonality
aspect of it, so the river herring adults would only be in the system during the
spring of the year for a relatively short period of time, which wouldn't necessarily
overlap with phytoplankton maxima. But the juveniles, on the other hand, are
there, pretty much the rest of the year. So, from spring until fall until it gets cold
enough and they all go to the ocean. I'd be interested to give that some more
thought and just think about it. But yeah, it sounds like from the studies you've
looked at, the top-down control is not much of a factor.
• Hans: And it's largely because these blooms can be very episodic and the grazers
aren't going to be able to catch up on that.
• Wilson: Right, got it.
• Karen: Coming back to the questions in our agenda. There were 4 questions and
the choice of answer is yes, no or more data is needed. I am going to run through
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the questions and ask SAC members to let us know where you’re at on the
different questions.
1. Is the existing chlorophyll-a standard protective of SAV?
o Jud: It seemed as though what Nathan was telling us, is that it was the
assessment process, not necessarily the standard itself, that was the
challenge.
o Hans: Yes, I would agree with that. It’s also one of those ‘it depends’
kind of answers because as he pointed out, it can be more or less
important depending on what the other optical components are doing.
o Jud: So, we should have more discussion on that in the next meeting.
o Hans: Anybody else have any input on that?
o Lauren: I felt like I heard no, but there is some places where that may
not fully explain everything that's happening.
o Hans: Yeah, I think that's the right answer.
o Martin: I think one other aspect from a lot of what Nathan was saying is
there's a mismatch between the construct of the current standard
versus how you would try and protect SAV or other aquatic uses really
in Albemarle Sound.
o Hans: Yeah, good point. I don’t know if we want to say unlikely or
somewhere in that range.
o Mike: Going along with that and the info that Nathan provided earlier
and then just to me also the historic mapping showing the losses over
time that that would indicate that “no” right now.
o Karen: Heard 2 No’s where does everyone stand?
Hans (unlikely), Jud (no), Martin (need more info *see below), Wilson
(need more info), Fritz (didn’t respond), Lauren (no), Mike (no)
We will need more discussion on this at the next meeting.
o *Martin: I think we need to take a look seriously at the construct of the
standard as part of the process that is assessed. When you go impaired,
where chlorophyll is really a driver of productivity in the system and
would better be suited on some sort of central tendency or a growing
season average which was where the number 40 actually was
generated from. Need more information.

2. Is the existing chlorophyll-a standard protective for clarity standard?
o Jud: We’re setting up this clarity standard for it to be protective of SAV.
So, it would seem to me the answer to this question would line right up
with the answer to the last question.
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o Hans: Yep.
o Karen: Anyone disagree with that last statement that the answer to this
question would line right up with the answer to the last question?
o Martin: Agree.

3. What is the connection between chlorophyll-a and nitrogen and phosphorus?
o Hans: There's a strong relationship between nitrogen inputs and
chlorophyll production in our sounds and in the lower river systems in
North Carolina. Of course, phosphorus could play a role if there's an
awful lot of nitrogen that comes in, then phosphorus becomes the co-
limiting nutrient. But overall, I think the connection is strongest
between nitrogen inputs and chlorophyll production, and in part that's
true because there's just a lot of phosphorus in our lower systems,
most of it natural, including in the sounds where it's been trapped for
eons as marine phosphorus. So, I think we can say “yes” particularly
with regard to nitrogen inputs.
o Lauren: I like that answer, so “same” = yes
o Martin: I think ultimately the drivers are N and P. In sort of controlling
productivity and the challenges come into seasonal delivery and all
because you can have lower concentration in winter but delivery down
into the system. So, I mean it's a question sort of on that management
level of how to reduce, once you have the conclusion that you do need
to reduce.
o Hans: Yes, I think if the question is restated, is there a connection
between chlorophyll and nitrogen and phosphorus inputs? The answer
is definitely “yes.” Because nitrogen tends to be on the short end of
things, often it tends to be the more limiting nutrient, but I agree,
phosphorus is important too, particularly if you get episodes of high
delivery of nitrogen to the system.
o Mike: I was just going to go along with Marty and Hans. What's
important is to think about flow and residence time and time lags. You
can have really turbid events and you might not get a reaction right
away. But then later, when the water clears up and there's a lot of
nutrients, some more problems sort of a thing. But just some of those
issues where some of the things we can't control about our rainfall and
big storms and things like that. But overall, a goal of having less inputs
is helpful.
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o Karen: I’m hearing general consensus that there is a connection
between chlorophyll-a and N and P. Are there any additional data
needs related to this? Looking at what that connection is?
o Hans: Well, the connection with chlorophyll-a is that nitrogen is
required to synthesize chlorophyll-a, so you know it's a structural
component of chlorophyll-a. Nathan has shown this data before that in
Albemarle Sound there's a strong relationship between the increase in
total nitrogen inputs and the increase in chlorophyll-a. Phosphorus is
really required for lots of biogeochemistry in the cells, including energy
production and stuff like that. So, we can definitely know what the
connection is in terms of the biochemistry.
o Libby: Is it helpful to look at it as a reduction, as a standard or as a kind
of load reduction and how much we need to reduce it to be protective?
o Hans: Oh, yeah, that's the ultimate question. And there is ongoing work
to address that. Nathan has had several students working on that issue.
We've done some work on it using dilution bioassays. I mean we
worked on that on the Neuse ages ago to help establish the TMDL for
nitrogen. So that is the really important question. So, the question is
really how much reduction is needed in terms of external loads and
what is the importance of legacy nitrogen and phosphorus that's
already in the system? In other words, you know if you reduce those
nutrients, can the system still operate on internal stores for a while
before we start to see a benefit. I know that's a very long-winded
answer to your question.
o Libby: Right, so that work is still ongoing?
o Hans: Yeah. And we need additional work in other places too.
o Martin: I think the qualitative answer is easy, that yes, nitrogen and
phosphorus inputs affect chlorophyll. How to address and what levels
to address are more complicated. I think loading reductions in sort of
the management strategy is the approach rather than trying to set
criteria. I don't know how you would set criteria that effectively can get
rid of some of the load that you don't want coming down but not have
unintended consequences of impairing a water in other seasons. So, I
think it's more of a management scenario rather than a criteria. Just
because of the seasonal variation of loading because a lot of times
concentration goes down in the loading events that you want to try and
diminish.
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o Hans: Yeah, I think we're saying very complimentary things there. I
would agree with Marty's point about it being a real critical
management question.
o Karen: Any other discussion points on question three related to N and
P?

4. Recommendation(s) regarding the chlorophyll-a standard? Assuming the SAC
is not ready for a recommendation at this time? Based on the answers to the
first few questions, looking for some more information and discussion on
questions one and two. Is that a fair assessment?
o Hans: Yeah. Cam’s point was really good there in terms of the use, the
issue of use. The standards are going to have to deal with the issue of
the use of the waters as well as the clarity issue.
o Lauren: So, my thoughts based on what we've talked about today is I
think what may be the eventual recommendations or in my hope would
be that they're kind of multiple chlorophyll levels. We're going to have
a chlorophyll that we think works better than the 40, but lots of details
to be determined. Based on the Cyano HABs conversation, there might
be a kind of second area type of chlorophyll and then sort of look at
that overall and see if it becomes 2 regions worth of chlorophyll or kind
of a thing like that just based on the different endpoints or if they're
similar enough, maybe you just keep it simple and it's one parameter
because they're close enough and the end of our analysis that would
streamline things instead of creating way more assessment
methodology work for the department.
And then I think if you have chlorophyll numbers in place out of this
recommendation, that can influence N and P reductions through non
criteria like management strategies or whatever, it's kind of what I'm
hearing is possible, but maybe I'm being optimistic.
o Karen: Thanks Lauren. Thanks for providing this synopsis of where
we're at. Any feedback on Lauren?
o Wilson: I like what I have heard, but I'm still challenged by the
complexity of the system, you know, and the relationship between
chlorophyll-a and N and P and production and use. It's kind of
overwhelming when you think about all that. I wonder if anybody has
ever tried to approach it from sort of a matrix perspective. What do we
think would be an optimal level? Is there such a thing? What's an
optimal level that would result in the desired water clarity, productivity
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and optimal use? Is there such a thing? I think we can think about that
at least and maybe there are some studies out there where people
have looked at that sort of a question. What's optimal when you throw
all these ingredients into the water criteria soup, what gives you the
best flavor is that a good metaphor?
o Hans: Yeah, I know where you’re going with this, I think I’d like to go
back to Cam’s point again that if we target use and environmental
health issues of water use upstream, which is where most of the
problems are in the riverine components, then you know there are
going to be some benefits in terms of the optical issue downstream
where we have the sea grasses and that's kind of an unpredictable
thing. But you would think that it would be beneficial in the long haul.
So, I think the question is do we target chlorophyll, where it's going to
have the maximum impact on human use (recreational use)
detrimental things upstream, like low oxygen events and fish kills and
things like that. I think that should be the priority, really. And then what
can we expect in terms of improvements in clarity based on chlorophyll,
once we've imposed those controls, does that make sense Cam?
o Cam: Yeah, I think this sounds like kind of adaptive management. We
take the one that's right in front of us to fix a problem and see how it
impacts the other.
o Karen: I appreciate the discussion so far, I am going back to the agenda.
To Cam’s discussion point, if you're ready, Cam to talk about
assessment methodology for the clarity standards?
o Cam: Sure.

5) Considerations for Water Quality Assessment and Monitoring: Current & Proposed for
Clarity (Cam McNutt) presentation with slides:
• Background on what happens to our other parameters once they’re put in place
and then develop an assessment methodology to decide if we’re meeting those
criteria.
• Standard vs Assessment process: Standard development is science based,
protective of uses, implementable in permits and in assessments. Assessment:
isn’t science based, but negotiated from guidance from EPA, is it reasonable or
not, consideration for measurement error, data collection methods, data noise,
and other considerations. By the end of the assessment process, you may have
something that doesn’t look like the standard anymore. EPA and EMC weigh in on
these things.
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• Went through some definitions of terms.
• The Integrated reporting framework: Assessment = Assessment Unit (waterbody)
= Parameter (clarity) + Criteria Status + IR Category
Assessment is equal to the assessment unit and that's the spatial component of
the water body. And in this case, it's the SAV area specifically and the parameter
(clarity), which is different than a lot of our other parameters. And then the criteria
status, which is your meeting criteria data inconclusive or exceeding criteria and
then that translates into an integrated reporting category, which categories 4 and
5 are the ones that are considered impaired. The Integrated Report is really a list
of water bodies where we have to do something for the Clean Water Act.
• Tier III PAR Data Collection Methods Draft: (Tier III data used to inform regulatory
decisions). Asking the SAC to look at the data collection methods and give input.
1. Extinction coefficients shall be collected using approved meter.
2. Data will be collected within 5 meters of the deep edge of SAV area.
3. Instrument shall be at least 0.5 meters off the bottom - Are we stirring things
up when the measurement device is thrown in?
4. Data must be collected between March 1 and October 31 (8 months).
5. Data must be collected during at least 3 months of the above period.
6. Annual growing season medians will be calculated for this period each year.
• Showed an example of a decision tree they’ve used in the past.
• Ten percent excursion rate: the 10% excursion rate that comes from older
guidance from the 80s. The way that the guidance is we apply it to 88 different
parameters in North Carolina, what the science on that 10% is because we have 10
fingers, seems reasonable.
And then in the case of metals, it's not necessarily in agreement whether we use
some percentage or whether we use the timing between the excursions. So,
there's some discussion on that as well. So, whenever someone starts adding
other things on top of that 10%, that's not increasing the amount of science, it's in
the process. It's just other parts of the decision tree to get you to a 303(d) list or
not to a 303(d) list.
• When the EMC wanted to put in that 90% confidence consideration before
something went on the 303(d) list, they wanted to make sure it should be on the
303(d) list. They were even saying things like 85%, 90%, whatever's more scientific,
that's literally what it kind of came down to. After one round of that we were
removing things from the 303(d) list that were anything below that. Went back
and forth with EMC and EPA, until we ended up with an assessment process for
most of our parameters that now has 27 different endpoints instead of four.
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But the clarity standard is worded in a different way where a lot of these
considerations may or may not be applicable.
(*see Cam’s slides to understand comments below)
Our confidence in meeting criteria curve and the number of excursions that you
have and a sample size of 60. When we used the flat 10%, so 7 excursions out of
60, that's just over 10%. And our confidence that we were exceeding criteria was
in the 60s and our confidence that we were meeting criteria was also in the 60s.
Evidently, no one was happy with that. So, we bumped that up to 303(d) list in the
90s. The problem we ran into is that we were removing things from the 303(d) list
with less than 1% confidence that we were meeting criteria and that's where the
40 came from, where the lines crossed. We picked 70 because it was the closest
number that we could use to what the existing one was, which was the 60.
So basically, we just outlined this to stay as close to what our methodology was,
but put these confidence considerations in there. So, our gray area, our data
inconclusive used to be 6, which was exactly 10% in our model data set of 60 and
that's monthly data for five years.
Our excursion right now is closer to 17% and that's what Nathan was using when
he said that the chlorophyll median using this assessment methodology that would
be around 22.
• So that's based on our current methodology, but if you were to change that
methodology to a median, then you don't necessarily have to change the standard.
You can use the median instead, so that's kind of where he arrived at that.
• What I'm proposing so far as an outline for the clarity standard, and it says in the
standard median extinction coefficient, the growing season, meaning is exceeding
0 times in our 5-year assessment period is basically if you collected enough data,
say you had five months, one year and you have a growing season median and
then you have 3 the next year. If any of those are over the clarity, that median is
over our clarity extinction rate, then you're going to say it goes on the 303(d) list as
long as the data were collected per whatever our decision is on how the data
should be collected. So that's a pretty simple way to do this. You only have a
couple of different decision points. Same way, if we're going to say it's meeting
criteria, as long as all of the growing season medians are above that extinction
rate, then we can say it's meeting criteria.
• Considerations like do we have the presence of SAV data collected with Secchi? Do
we have concurrent turbidity, concurrent chlorophyll-a data, CDOM data? Lots of
other considerations that could be put into the assessment process that aren't
necessarily part of the water quality standard and that will be something that DWR
will be doing working through this process. But right now, it's going to be pretty
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closely tied to the standard because of the way the standard currently has been
proposed, but all these other things will need to be considered and we'll have to
decide if we're using Secchi data, would we consider that Tier 2 data or
surveillance data, effectiveness monitoring data and we'll be using field
instruments here, so the certification part of that will be about staff and
instruments whether you're following SOP's and that sort of thing.
• So, these are the kinds of things that we can consider and I think we actually
added a few more today. I'll have to add these in when I go look back at the notes.
Like how close are we to the SAV, is it representative of conditions in the SAV,
where do we measure it, whatever the depth was, 1.2 or 1.7 meters, and then the
big one for me is how many months do we need to calculate the growing season
medians? Is there some minimum or do we just take what we have so those are
kind of the three numbers that we need in order for us to proceed with
determining how much it will cost to collect a sample and then we can go with
how many sites should we use in our first go with this based on how we can get to
them. But SAC probably doesn't need to consider which stations just needs to
consider what sampling technique is going to best represent or is going to provide
us with data that we can use to make the assessment.
o Wilson: Can you send the presentation to us?
o Cam: Yes
o Jud: A few things here we need to revisit in next meeting for reclarification.
o Lauren: Do you have a coverage for the map historically and present? Do
you know the size of that? What‘s the biggest section? Is it 25 meters from
the shore? I was just curious of the kind of scale.
o Cam: It's pretty variable where it's mapped and some of it might be
accessible from the shore and others might not be. So, we're going to go
through the existing marine fishery stations and try to find the ones that
are the representative of high and low and all the various conditions that
we have and figure out how we can get to those.
o Jud: There's a historical maximum extent layer that is spatially articulated
and then there would be some question as to how much do we want to
rely on that layer as a reference point? One other thing is that our high
salinity SAV layers are pretty up to date and precise, our low salinity SAV
layer is not, so you know the fudge factor is going to be a lot more in our
low salinity application of the standard.
o Cam: And with the high salinity the mapping is more contiguous and there
are larger areas that are hooked together, and some of the low salinity
ones, they get really spotty and separated from each other, which kind of
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makes it more difficult to apply it across multiples versus in the high
salinity, you might be able to have an assessment unit in a high salinity area
that is very big compared to one that's in a low salinity area where there
might be more variability.
o Mike: I was just thinking with the time frame of collection, but maybe it
gets taken care of just cause it's unsafe, they're in stormy conditions. If the
data is collected when it's really stormy or a lot of flow, I wonder if there's
a reason to specify that there's certain conditions where it might cause
some really weird data that you don't want to sample during.
o Cam: And we have that built into the SOP in general that we don't go out
during hurricanes type of thing.
o Mike: That’s good.
o Cam: It needs to be safe and we also have acknowledgement that if you
have an extreme drought condition, we consider the data differently and
maybe we don't use some of those data.
6) Next Steps (Karen Higgins)
• Cam will share presentation
7) Closing/Housekeeping Remarks (Elizabeth Liebig)
• Lots to discuss moving forward and we will continue to discuss these topics at the
next meeting.
• I'll send out the agenda with some things to consider, but I do encourage you to
use this time to dig into literature and research and discussions as well and pull
anything together that you would like to talk about too for the next meeting.
• Also take a look at the pdf that Cam will be sending out and be prepared to give
your opinions, your thoughts, and have a consensus vote on those parameters as
well.
• Next meeting is November 17, 1:00-4:00 pm.
8) Meeting Adjourned (Karen Higgens)

Tim Ellis shared these links:
https://coastalreview.org/2023/06/large-scale-survey-of-albemarle-sound-underway-for-noaa/
And
https://www.nv5.com/news/nc-hydrographic-survey-announce/