[Coral-List] Fwd: How can we "bleach proof" transplanted coral nurseries?

Damien Beri beridl at g.cofc.edu
Thu Aug 24 16:01:27 EDT 2017


Most of the algae used in the aquarium industry have the potential to become some serious exotic species. Example: chaeto, caulerpa.  And some macro algae have more preference for different nutrients.  One article based on Ulva and Chaeto in Peel inlet Australia showed that ulva uptakes way more N than P whereas the opposite is with chaeto.  In this case a combination of the two would correct for excess runoff, however the two compete for light and chaeto always wins.

Also, when used in aquariums the algae is ALWAYs separated by physical barrier because of the ability for it to spread and smother corals, clog pumps, and flood your home.  Some coral nurseries have shown bundles of chaeto smothering outplanted corals which would be the equivalent to the hazards of placing macro into the main display of an aquarium.

When macro algae competes against itself, self shadowing has the potential to release deleterious compounds into the water as the bottom layers of macro decay. 

Lower water flow caused by dense macro algae mats also causes Cyanobacteria outbreaks, fungal, and bacterial outbreaks as a result.  It must be pruned.  

I do believe there should be massive turf scrubbers at every single outlet of every single runoff near coral reefs, the key is to figure out how to work with the existing macro algae present, or even the phytoplankton present as growing phytoplankton to feed corals converts N and P to coral biomass. 

Some aquarists use dosing mechanisms to take water out of the aquarium and fill a phyto culture which absorbs N and P and then dose the phyto right back into the tank to feed corals.  You consume N and P through growing phyto from aquarium water then dose the live home grown phyto back into the aquarium..  

There are also products which provide us state for fungus to grow called "Algon" which readily consumes N and releases a smelly sulfur gas.  It's probably got bacteria in there too. 

Also, if a refigium is your main nutrient export in aquaria, it has to be at least 20% of the aquarium volume to work effectively.  


Sent from my iPhone

> On Aug 23, 2017, at 11:35 PM, Scott Wooldridge <swooldri23 at gmail.com> wrote:
> Sorry, it was remiss of me not to also include mention of an excellent
> experiment by Ted McConnaughey (2000) in which he meticulously measured (in
> a aquaria setting) the beneficial impact of non-calcareous algae in
> promoting coral health under modern ocean conditions.
> https://www.researchgate.net/publication/319255771_Community_and_environmental_influences_on_reef_coral_calcificationphotosynthesis
> In the experiment, he showed that the noncalcareous alga Chondria
> sp.reduced molecular seawater CO2 concentrations by 73%, which caused
> photosynthesis and calcification rates to increase (>2-fold) in co-located
> Acropora and Montipora colonies. By inference, i suggest this would also be
> manifest as increased bleaching resistance - but lets test it.
> Great, great experiment with loads of details for designing and monitoring
> an upscaled field experiment of a similar ilk. I have the greatest of
> respect for the research and ideas of Ted.
> scott
> https://www.researchgate.net/profile/Scott_Wooldridge
> cited literature
> McConnaughey (2000) Community and environmental influences on reef coral
> calcification. Limnology and Oceanography 45:1667-1671.
> ---------- Forwarded message ----------
> From: Scott Wooldridge <swooldri23 at gmail.com>
> Date: Thu, Aug 24, 2017 at 12:04 PM
> Subject: How can we "bleach proof" transplanted coral nurseries?
> To: coral-list at coral.aoml.noaa.gov
> Dear fellow coral researchers,
> I have received numerous emails asking to suggest possible ways that we may
> be able to enhance the thermal bleaching resistance of transplanted corals
> - if as i suggest, intracellular CO2-limitation of the endosymbiont
> phyotosynthetic machinery is the underpinning mechanism.
> Just drawing quickly attention back to the following manuscripts:
> https://www.researchgate.net/publication/308746785_Excess_
> seawater_nutrients_enlarged_algal_symbiont_densities_and_
> bleaching_sensitive_reef_locations_1_Identifying_
> thresholds_of_concern_for_the_Great_Barrier_Reef_Australia
> https://www.researchgate.net/publication/317100418_
> Instability_and_breakdown_of_the_coral-algae_symbiosis_
> upon_exceedence_of_the_interglacial_pCO2_threshold_
> 260_ppmv_the_%27%27missing%27%27_Earth-System_feedback_mechanism
> It is clear, that the biological challenge is to keep endosymbiont
> (symbiodinium) levels at optimal levels (~1.5 x10^6 cells.cm2 host tissue
> in branching corals). Two factors in combination promote 'excess' densities
> - elevated pCO2 and dissolved inorganic nutrients (principally nitrogen)
> concentrations.
> Thus, the bioengineering challenge is also clear. We need to lower pCO2 and
> DIN in the immediate vicinity of transplanted corals (or coral reefs in
> general).
> In my opinion (and being a pessimist/realist? in my belief that
> governmental institutions have the political will to reduce pCO2 or DIN
> runoff to the levels required for a stable coral symbiosis) the only hope
> we have is to investigate the beneficial role that co-transplanted seaweeds
> / macro-algae / crustose coraline algae can play.
> Active seaweed growth has the potential to draw down both DIN and pCO2 in
> the seawater in their near vicinity. Note: seaweed precipitate no (or
> little) CaCo3 (= source of CO2 to seawater)
> The use of "algal scrubbers" to reduce DIN levels in aquarium systems is
> common practice. Can we do something similar within our transplanted coral
> nurseries and co-locate seaweeds?
> Obviously, field research is needed here. But a couple of interesting
> results are noteworthy, and suggest the successful outcomes may be possible.
> Firstly, in the lab, Yuen et al. (2009) were able to demonstrate that algae
> (in this case crustose coralline algae) when co-located with Acorpora
> digitifera in small tanks were able to quickly (days) draw down DIN  (and
> possibly pCO2?) levels. This resulted in the exact benefits expected if
> intracellular CO2-limitation is a controlling feature of endosymbiont
> behaviour. It increased photophysiology efficiency (Fv/Fm, ETR), and
> reduced the level of bleaching and mortality compared to non treatment.
> https://www.researchgate.net/publication/319255076_
> Published_manuscript_Yuen_et_al_2009_Effects_of_live_rock_
> on_the_reef-building_coral_Acropora_digitifera_cultured_with_high_levels_of_
> nitrogenous_compounds_Aquacultural_Engineering_4135-43
> This is a promising result in the lab. But what of any field evidence?
> There is an interesting dataset by Jompa and McCook (1998) who (quite by
> accident) recorded much lower levels of bleaching and mortality in corals
> that were surrounded by seaweed (particurlarly Sargassum spp) during the
> 1998 mass bleaching event on the inshore Great Barrier Reef. The authors
> were at the time undertaking another unrelated experiment that involved
> manually removing seaweed from some reef sites. They observed a dramatic
> (2-3 fold) increase in the level of coral bleaching at sites from which
> seaweeds had been removed.
> https://www.researchgate.net/publication/319255226_The_
> beneficial_role_of_seaweeds_in_reducing_coral_bleaching_
> on_the_inshore_reefs_of_the_Great_Barrier_Reef_1998
> The authors speculated that the seaweed may have been providing a shading
> benefit (and this may be true). However, could it also have been the case
> that the seaweed had reduced seawater DIN and pCO2 in the vicinity of the
> corals? I think we need (with haste) to test this possibility.
> One issue may be that we need the seaweed to be in an active growing state
> to be of real benefit. For example, in artificial wetlands used to treat
> nutrient effluent it is well know that nutrient uptake rates into plant
> biomass are high initially and then tail off. This necessitates (for this
> system) that the plants be harvested and removed at the end of each growing
> season. Luckily for us, seaweeds tend to die back in the winter months
> naturally and we may not need to worry about this? Anyway, now i am just
> guessing.
> I hope this may be of some benefit in sparking the challenge to that
> eco-engineer/entrepreneur.
> scott
> https://www.researchgate.net/profile/Scott_Wooldridge
> Cited Literature
> Jompa and McCook (1998) Seeweeds save the reef. Unpublished report.
> Yuen et al. (2009) Effects of live rock on the reef-building coral Acropora
> digitifera cultured with high levels of nitrogenous compounds. Aquacultural
> Engineering 41:35-43
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