Harmful Algal Blooms (HABs)

1. Harmful Algal Blooms (HABs) Outline • Re-introduction to phytoplankton and HABs • Hypoxia and disruptive blooms • Toxic microalgae • Regional Case Studies

2. “Phytoplankton” is a messy word • Literally = errant or wandering plant • Often called “algae” or “microalgae” • Any single-celled organism (usually protists or bacteria) in aquatic systems that performs photosynthesis • They aren’t plants (but it helps to call them that) http://www.artinsteel.co.uk/ userimages/diatom01.jpg http://ux.brookdalecc.edu/staff/ sandyhook/taxonomy http://farm3.static.flickr.com/

3. Phytoplankton are a Functional Group • Grouped by what they do, not who they are • Ex. – Mammals are a taxonomic group, put different function (grazers, scavengers, predators) • Many problems with this grouping as well • Some live on the bottom – “microphytobenthos” • Some are predators and don’t always do photosynthesis • Some are parasites • Incredible genetic and functional diversity

4. Global Importance • 45-50% of global primary productivity (fixing carbon into food) • Production of oxygen • Responsible for large fraction of global carbon burial (deep ocean) • Base of almost every aquatic food web • Role in C cycle gives • them a key role in • climate change SeaWiFS/ORBIMAGE fishweb.ifas.ufl.edu www.surrey-arg.org.uk/ http://assets.nydailynews.com

5. “HAB” is also a messy word • Bloom = domination by one species/group or a rapid, dense proliferation of phytoplankton (a poor definition) • “Harmful” for several possible reasons • Produce toxins • Hypoxia(low oxygen) • Exclusion/Shading - disruptive to other phototrophs • Physically harmful -obstruct fish gills, form large mats or foams serc.carleton.edu serc.carleton.edu

6. …and covers a wide taxonomic range • Toxic or otherwise harmful species across many taxa • Variety of physiology, ecology, and toxicology to consider • Beware of broad explanations or solutions for HABs Falkowski et al 2004

7. HABs are not new… • Believed to be one or more of the Biblical Seven Deadly Plagues (Ehrenkranz and Sampson, 2008) • Red tides and toxic fish noted by Spanish explorers in 1600-1700s Florida (Tester and Steidinger 1997) • Many human mortalities from HAB shellfish poisoning in last 300 years (Lewitus et al. 2012) • Toxic bloom in California, 1961 inspired “The Birds” (Bargu et al. 2012) • A local “jubilee” of seafood is a hypoxia event • Many other historical accounts indicate hypoxia and toxic algae events The Daily Telegraph

8. …but they are on the rise • Global increase in HABs was previously under debate • Strong scientific consensus that HABs are increasing due to • anthropogenic influence (Heisler et al. 2008) • Increased eutrophication (nutrient pollution) • Climate change • Invasive species • Strong link between local nutrient pollution and increases in HABs Parsons et al. 2002 Anderson et al. 2002

9. Climate change likely to exacerbate HABs, particularly cyanobacteria • Phytoplankton growth generally increases with temperature • Cyanobacteria (blue-green algae) more likely to dominate due to high termperature tolerance • Many toxic cyanobacteria, also can be ecologically unfavorable (poor food source for higher trophic levels) • Warming implicated in many cyanobacteria HAB problems world wide (Ex. Lake Taihu, China) Paerl et al. 2011 Paerl et al. 2011

10. Invasions may also play a role in HAB expansion • Some HABs linked to ballast water exchange (Hallegraeff, 1998) and known HAB species found in many ballast water surveys (Burkholder et al. 2007; Doblin et al. 2007) • HABs that form resting stages (cysts) or can survive long periods of darkness are prime candidates for ballast water invasion • Bio-fouling on ships may also be an important source of invasive species (Lopez-Rodas et al. 2010) physicscentralcom Safety4sea.com

11. Hypoxia • Profound ecological and economic consequences • Eutrophication implicated in the global rise in hypoxic zones (Diaz et al. 2001) • Hypoxia formation actually relies on several factors: • Physical processes (i.e. wind and mixing) • Nutrient inputs to supply phytoplankton growth • Sufficient phytoplankton growth and export to bottom waters • Sufficient bacterial decomposition in bottom waters to deplete oxygen Longislandsoundstudy.net

12. Hypoxia and Fisheries Decline • In addition to sporadic fish kills, hypoxic zones drive down overall fisheries production (finfish and shellfish) • Louisiana Dead Zone – Causes and estimated fisheries loss of 470 million pounds of seafood (Conservation and economic loss) • Most costly effect of eutrophication/ over abundance of phytoplankton www.cop.noaa.gov Hugo Ahlenius, UNEP/GRID-Arendal

13. HABs can be dispruptive by excluding other species Usac.org.uk • Dense blooms due to eutrophication can shade other important • Made worse by overfishing/loss of key grazers • Coral reefs • Macroalgae such as kelp News.fiu.org • Particularly damaging to seagrass • Microalage and macroalgae have caused much of seagrass die-off (Duarte 1995; Hauxwll et al 2003) due to shading • Eutrophication can shift overall production from benthos to water column. Loss of benthic production enhances resuspension making seagrass recovery harder (Olesen 1996)

14. …or by being a poor food source • Some species are harmful by displacing better food sources • Cyanobacteria lack essental fatty acids (e.g. sterols) give them poor nutritional quality for zooplankton (Martin-Creuzberg et al. 2008) and bivalves (Basen et al. 2012) • Toxic cyanos such as Microcystisproduce colonies near zooplankton and reduced grazing Wikipedia Wikipedia

15. …or both! • Aureococcusanophagefferens – The Brown Tide • Blooms originated due to eutrophication • Tiny cells were a poor food source for bay scallops and grazers. Dense blooms out-competed other phytoplankton • Like seagrass problem, shifting biomass from benthos (microphytobenthos growing on bottom) to water column • Destablizes sediment, more resuspension • Dark environment perfect of Aureococcus(adapted to low light) • Persistent blooms wiped out bay scallop industry in New York Newswise.com MacIntyre et al 2004

16. Alternate Stable States • In a stable state, ecosystem can receive some amount of disturbance, but will tend to return to natural state • If disturbed enough, dominance of stable state species is lost • Conditions shift to favor a new stable community Tipping Point Stable State Two Stable States • In reality, ecological disturbance changes the shape of the curves • Process can be irreversible on short time-scales (human time) www.theshallowresearcher.com

17. Toxin-producing HABs • Large mortalities of fish or shellfish • Mortalities of wildlife such as birds or marine mammals • Direct toxic effects to humans • Human poisonings through contaminated seafood • Large economic impacts due to monitoring, medical costs, fisheries closures • Challenge: Aside from understanding HAB ecology and toxin production, must also assess trophic transfer, biotransfomation , and pharmacology of toxins ADPH

18. Most toxin producers are dinoflagellates • Most ecological, human health, and economic costs are due to dinoflagellate HABs • Pose unique challenges for HAB research • They are mixotrophic (act as plants and animals), more difficult to describe ecology • Some cause harm at very low concentrations, hard to detect • They have enormous genomes, difficult for full sequencing Comenius.susqu.edu bewiki.kenyon.edu

19. With some important exceptions Pseudo-nitzchia– the toxic diatom Microcystis– colony forming cyanobacteria that produces neuro- and hepatotoxins wikipedia Prymnesiumparvum – Small prymnesiophyte that produces parvotoxins, plagues aquaculture systems Gulfbase.org

20. Variety of toxins and diseases • Saxitoxins– Paralytic Shellfish Poisoning (PSP) • Alexandrium(a dinoflagellate) and some cyanos • Major problem in Northeast U.S. and Pacific Northwest • Brevetoxins – Neurotoxic Shellfish Poisoning (NSP) • Caused by Karenia(dino) • Major problem for wildlife, tourism, and fisheries in Florida • Ciguatoxins – Ciguatera Fish Poisoning (CFP) • Gambierdiscus (dino) • Only in tropics, poorly understood • Most common disease due to HABs, 2nd most common illness due to fish • Domoic acid – Amnesic Shellfish Poisoning (ASP) • Pseudo-nitzschia (diatom) • Global problem for wildlife and shellfish • Okadaic acid – Diarrheic Shellfish Poisoning (DSP) • Emerging problem in Gulf of Mexico and Pacific NW Whoi.edu All structures – Botana 2008

21. Pseudo-nitzschia • Diatom that occurs in temperate waters worldwide, dominant community member • Major bloom former in northern Gulf of Mexico • Produces domoic acid, accumulates in prey species and poisons their consumers. • Similarities in bloom conditions • Pulses of nutrients • Mixing • Upwelling, estuaries, oceanic fronts • Appears to have a ruderal (weedy) growth strategy (MacIntyre et al. 2011) AP Texas PWD

22. A persistent threat to fisheries and wildlife • First human poisonings raise attention • 1987, Prince Edward Island, CA • 3 killed, ~10 brain damaged, ~100 sickened • Consumption of domoic acid contaminated blue mussels • Causes many shellfish closures in Pacific Northwest AP • Poisonings since in wildlife • Frequent sea lion mortalities (Scholin et al. 200) • Bird mortalities (Work et al. 1993) • Possible whale and dolphin illnesses (Twiner et al. 2009; Fire et al. 2011 • Found in commercial fisheries in GOM (Liefer et al. 2013; Del Rio et al. 2012) Liefer et al. 2013

23. Gambierdiscus and Ciguatera • Ciguatera Fish Poisoning (CFP) is the most common illness due to phycotoxins; 25,000 – 500,000 cases per year. • Seafood containing ciguatoxins (CTXs), lipophilic Na-channel activating toxins • Ciguatoxins originate from gambiertoxins, produced by species of Gambierdiscus, benthic dinoflagellate • Common in shallow tropics. Florida Keys, Hawaii, Puerto Rico, and USVI • Endemic in regions like USVI, Puerto Rico, parts of South Pacific (>5% of population likely has had it) Maria Faust - NMNH Maria Faust - NMNH University of Guam

24. Complex trophic transfer of Ciguatera Amberjack Highest toxin concentrations, most toxic congeners, mobile vectors of an immobile toxin source Queen Triggerfish White Grunt Red Hind Mesopredators/ large herbivores Gastropods Crustaceans Parrotfish Surgeonfish Biomagnification Increasing Ciguatoxicity Biotransformation Variety of primary consumers Epiphytic Gambierdiscus Inter- and intra-specific variation in gambiertoxin production and composition Turf Algae Macroalgae High variation in substrate types and selection

25. Kareniabrevis • The infamous “red tide” • Forms mono-specific blooms in Gulf of Mexico, mostly in Texas and Florida • Human poisonings are rare, usually from recreational harvest in closed areas • A major threat to Florida wildlife noaa.gov Hu et al. 2006 whoi.edu

26. A wide-ranging threat • One of the only HABs directly toxic to humans – waves will break Kareniacells, toxin gets in the air. Causes respiratory problems in humans • Toxin has caused large fish kills in western Gulf of Mexico • Widespread 2005 bloom killed things at all trophic levels (Landsber et al. 2009) ADPH Fowl River ADPH

27. Karenia red tides and endangerd/protected species • Several large dolphin die-offs (Twiner et al. 2012 and others) • Dolphins consume small planktivorous fish (like menhaden) that graze on toxic bloom • Can be very quick process • Manatees (Bossart et al.1998), including 829 last year • Florida manatee population already highly endangered and declining • Est. population = <10,000 • Some events (ex. 2005 bloom) killed everything in some locations (invertebrates, finfish, sea turtles, sharks) • Risk to endemic species Florida FWC Florida FWC

28. Conservation Implications of HABs • Impact of hypoxia and toxic blooms to already dwindling fisheries • Shifts in sensitive ecosystems (ex. Seagrass, corals) to algal dominance due to eutrophication and reduction of grazing fish • Threats to endangered/protected species, particularly those endemic to a small region (ex. Florida Manatees) • Loss of Confidence? • Effect on conservation interest as seafood resources are lost • Effect on conservation interest if eco-tourism is lost

29. Coping with HABs • Reminder: HABs and hypoxic zones have occurred naturally, inherent aspect of many ecosystems • Most of the HAB problems are highly complex • Phytoplankton communities are incredibly diverse and unstable • A wide variety of nutrient sources for eutrophication • Toxin production varies with conditions • Some toxins must accumulate and transform to have impacts • Three key approaches to HABs (and most conservation issues) • Mitigation • Monitoring • Prevention

30. HAB Mitigation • Biological Treatments • Macroalgae extracts (allelopathy) • Chemical Treatments • Clays • Copper sulfate • Physical disturbance • Boat mixing • Turbines • All of these options and other proposed ones have key drawbacks • Ecosystem effect difficult to predict • Costly • Long-term effectiveness? WHOI

31. HAB Monitoring • The only option for many HABs • Dinophysis -> DSP at low abundances • Gambierdiscus -> Ciguatera while being rare and not blooming • Monitoring and seafood safety • No known illnesses from Amnesic Shellfish Poisoning since 1987 • Automated monitoring prevented a DSP outbreak in Texas during a shellfish festival (2011) • Challenges • Better understanding of ecology, toxin production • Require highly skilled labor, technology • Blooms are “cryptic” • Expanding monitoring in undeveloped nations cop.noaa.gov baynews9.com

32. HAB Prevention • “An ounce of prevention is worth a pound of cure” – especially true for HABs • Addressing the key causes • Eutrophication • Climate Change • Species Invasion • Reducing eutrophication seems most likely to happen and most effective • Maintaining natural filters • Wetlands • Dissipating river outputs • Agricultural nutrient reduction • Run off buffers on farms • Fertilization methods • Human Development • Impermeable surfaces • Waste water treatment Less of this Less of this More of this!