SCIENTISTS WEIGH IN ON HARMFUL ALGAL BLOOMS

EVERGLADESFOUNDATION.ORG THE FOUNDATION SCIENTISTS WEIGH IN ON HARMFUL ALGAL BLOOMS

Melodie Naja, Ph.D., Stephen Davis, Ph.D., Thomas Van Lent, Ph.D.

THE EVERGLADES FOUNDATION 18001 Old Cutler Road, Suite 625 Palmetto Bay, FL 33157

NUTRIENTS AND ALGAE BLOOMS

There is both a local and a global perspective to the problem of nutrient pollution and the consequent overgrowth of algae they can fuel. Both are important, and The Everglades Foundation is providing leadership on both.

THE GLOBAL PERSPECTIVE Figure 1: The status of the planet boundaries. Source: Steffen et al. (2015).

Algae blooms are a global phenomenon and are most often point sources (urban and industrial) while diffuse sources fueled by excess levels of nitrogen (N) or phosphorus (P) (agriculture) contribute 38% of the total phosphorus load. — both essential elements for life and main components In North America, agricultural (non-point source pollution) of fertilizers. All countries with significant populations or is responsible for most of the phosphorus loadings into our agricultural activity are seeing these blooms. While some freshwater bodies4. Agriculturally-derived nitrogen is likely blooms are caused naturally, global runoff of fertilizer and even worse. While phosphorus application has leveled off, domestic wastewater production are fueling an increase nitrogen application has grown linearly over time. in the frequency, severity and duration of these blooms1. Further, certain kinds of algae can produce toxins, creating There is a general lack of awareness about the problem of an additional threat to environmental and human health. nutrient pollution, also known as eutrophication. If there is These Harmful Algal Blooms (HABs) are often associated some awareness, it is focused on a local problem with little with species of blue-green algae and the organism that recognition that nutrient pollution affects the majority of the causes red tide. planet’s freshwater bodies and coastal waters. Scientists recognize that remediation and recycling of these nutrients Scientists studying the stresses on the planet agree that is needed to restore and protect our aquatic environments excess N and P are among the most pressing issues and sustain humanity5. facing the planet, even more than climate change or ozone 2 depletion (Figure 1) . Scientific observations point to several Technologies for effective large-scale nutrient pollution major agricultural regions with excess phosphorus and removal/remediation are limited by cost6 or the need for nitrogen added and stored in the soil. Therefore, N and P large parcels of land with managed flow systems7. are considered as the main contributors to the transgression of a safe planetary boundary (a safe operating space within This is why The George Barley Water Prize is so important; which societies can develop and thrive while protecting the it recognizes a global problem and that we need to do 3 environment). According to another study , unsustainable something about it. The George Barley Water Prize is levels of phosphorus are being applied to more than 75% of focused on improving the cost-effectiveness of phosphorus the planets land surface (Figure 2). pollution removal from freshwater bodies. Likewise, it helps to address the basic economics whereby application of 3 The same study reported that about 62% of the total fertilizers is several orders of magnitude cheaper than anthropogenic phosphorus load to our freshwater is from removing it from the water.

EVERGLADESFOUNDATION.ORG . In order to sustain itself in nearshore areas, red tide also needs a large supply of nutrients – especially N and P. Given the timing and impact of Lake Okeechobee discharges this year, people are questioning whether these discharges are also providing a local source of nutrients to sustain this red tide, and evidence is mounting that these problems are connected.

A recent NOAA-sponsored study has shown that Lake Okeechobee’s discharge to the west coast may help to sustain red tide in coastal waters outside the Caloosahatchee9. In fact, Heil et al. 2014 demonstrated through mass balance work that high discharges from Lake Okeechobee to the Figure 2: A map illustrating the phosphorus pollution levels of global river Caloosahatchee could meet up to 100% of the N and P basins between 2002 and 2010. Green and yellow indicate areas where freshwater diluted phosphorus to the point of nullifying its ecological effects. demand of a nearshore/estuarine red tide, depending on Orange and red mark areas where phosphorus levels exceeded that dilution the size of the red tide event. This contribution declines with threshold, potentially contributing to the emergence of “dead zones” in freshwater gulfs and lakes. Source: M. Mekonnen and A. Hoekstra, https:// distance from the estuary and as the spatial extent of the agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017WR020448 - https:// red tide increases. Clearly, though, releases to the estuaries news.unl.edu/newsrooms/today/article/researchers-id-map-phosphorus- pollution-of-global-freshwater/ from Lake Okeechobee represent a viable and likely source of nutrients sustaining red tide.

THE LOCAL PERSPECTIVE According to recent calculations by Dr. Cynthia Heil (2018), a Senior Research Scientist from the Bigelow Laboratory for In 2018, the impact of nutrient pollution has gained much Ocean Sciences, 2018 Lake Okeechobee discharges to the attention in Florida with the sustained, intense red tide off Caloosahatchee Estuary could have met 10-100% of the N Florida’s Southwest Coast. In South Florida, our algae demand and 16-100% of the P demand of red tide in the area problems are not just limited to the red tide caused by the between Charlotte Harbor and Sanibel Island from January to algae species Karenia brevis. We also have blooms of June (Figure 5)10. A detailed technical report will be available blue-green algae (dominated by the species Microcystis shortly that will document the potential nutrient contributions aeruginosa) that stretch from the St. Lucie estuary (on the of the Caloosahatchee River to this year’s coastal K. brevis east coast), across Lake Okeechobee, and over to the bloom. Dr. Heil is also investigating the potential for the Caloosahatchee estuary (on the west coast). We have decaying Microcystis bloom in the lower Caloosahatchee also recently seen brown tide and diatom blooms in water River to provide another source of N to help sustain nearshore bodies such as the Lagoon and , red tide. This would indicate an additional, indirect impact of respectively (Figure 3). Lake Okeechobee discharges on red tide.

RED TIDE

Red tide is attributable to the overgrowth of a slow-growing, marine species of algae (K. brevis). Red tide forms offshore on the Florida Shelf and prefers warm marine waters, especially at salinity levels above 24 parts per thousand. Wind, currents, and temperature all play a role in bloom formation8. However, once a bloom is triggered, it can be carried closer to shore where it affects coastal communities.

This year’s red tide has been ongoing since October 2017, about one month after the passage of Hurricane Irma when stretched from the Florida Keys up along the 10,000 Islands to the Naples area. Nearly one year later, as we transitioned into the warmest months of the year, the red tide has expanded up to the Sarasota-Bradenton and areas and intensified, particularly in the area outside Charlotte Harbor (Figure 4).

We know that high nutrient loads from Lake Okeechobee discharges and local basin contributions are fueling inshore Blue-green algae in the St. Lucie canal at the S308 and nearshore blooms of blue-green algae across South Structure (Lake Okeechobee outflow) in July 2018.

EVERGLADESFOUNDATION.ORG WATER QUALITY HEAVY POPULATED IMPACTS AREAS IN SOUTH FLORIDA INDIAN RIVER LAGOON BREVARD Brown tide LAKE OKEECHOBEE/ CALOOSAHATCHEE Aureoumbra lagunensis AND ST. LUCIE RIVERS Blue-green algae bloom INDIAN RIVER Microcystis aeruginosa SARASOTA

JUNE 29, 2018 ST. LUCIE Algae

covering OKEECHOBEE PHOTO: DAVID MASSEY/ THE 90% of DAYTONA BEACH NEWS-JOURNAL the lake MARTIN RICHARD P. STUMPF, NOAA Atlantic Ocean Lake St. Lucie River Okeechobee

CHARLOTTE GLADES PALM BEACH

Caloosahatchee River Mar-a-Lago LEE HENDRY Everglades Agricultural WCA1 Area Blue-green algae bloom FLORIDA Microcystis aeruginosa WCA2A

COLLIER WCA2B

Big Cypress BROWARD SOUTHWEST COAST National WCA3A Preserve POPULATED Red tide AREAS Karenia brevis MIAMI- WCA3B DADE PHOTO: WPTV5

MONROE

Gulf of Everglades BISCAYNE BAY Mexico National Park Diatom bloom Chaetoceros sp.

FLORIDA BAY Seagrass die-off and algae bloom Synechococcus sp. 10 MILES

PHOTOS: STEPHEN E.DAVIS PHOTO: ANNA WACHNICKA/FIU Figure 3

EVERGLADESFOUNDATION.ORG HEAVY POPULATED AREAS MANATEE

RED TIDE FLORIDA CELL COUNTS CELLS/LITER

Low SARASOTA 10,000 to 100,000

Medium 100,000-1,000,000

High CHARLOTTE GLADES More than 1,000,000

Caloosahatchee River SUMMER 2018 RED TIDE The Florida red tide organism, Karenia LEE brevis, produces toxins affecting the FLORIDA central nervous system of fish and AREA other vertebrates, causing these DETAILED animals to die. The Florida Department of Health advises people with severe or chronic respiratory conditions to avoid red tide areas. Florida red tide Big Cypress can cause some people to suffer skin 10 MILES National irritation and burning eyes. COLLIER Preserve

IN MILLIONS OF CELLS/LITER 6 LEE LEE LEE LEE LEE LEE LEE LEE 5 COLLIER MANATEE MANATEE SARASOTA SARASOTA CHARLOTTE CHARLOTTE CHARLOTTE CHARLOTTE CHARLOTTE CHARLOTTE CHARLOTTE 4

3 LOCATION

2

1

0 JUNE 4 5 7 11 13 18 19 25 26 JULY 31

SOURCES: Florida Department of Environmental Protection, mapline.com

Figure 4

EVERGLADESFOUNDATION.ORG Figure 5: Percentage of estuarine K. brevis (kb) bloom N and P needs met by Caloosahatchee River loading from January – June 2018, with average weekly estuarine K. brevis concentration. No orthophosphate data was available prior to March 2018 to calculate loading rates. Source: C. Heil, personal communication.

MICROCYSTIS FLORIDA IN LAKE OKEECHOBEE, ST. LUCIE RIVER AND HEAVY CALOOSAHATCHEE RIVER POPULATED MARTIN AREAS

Highest toxin levels observed during the last 75 days Atlantic Lake St. Lucie River Ocean GLADES Okeechobee

Gulf of Caloosahatchee River Mexico Mar-a-Lago HENDRY HEAVY POPULATED LEE Everglades AREAS Agricultural WCA1 Area FLORIDA

AREA DETAILED

10 MILES WCA3A WCA2A

TOTAL MICROCYSTIN TOXIN LEE COUNTY S79 Upstream GLADES COUNTY MARTIN COUNTY Based on available COLLIER of Lock WCA2B noncancer health 500 463.34 500 500 effects information, C44S80 MICROGRAMS/LITER Big Cypress EPA is recommending Alva Bridge 400 400 St. Lucie Lock 400 National 4 micrograms per liter 10-50 100-149 Prosperity 308.07 495.06 as a value protective Preserve 300 300 300 51-99 150+ Point SE near of primary contact Marina Davis S77 Central recreation for 200 160.41 Boat 200 Moore 200 Marine microcystins. If used as Ramp Haven 110 a swimming advisory to 100 100WCA3B 100 protect swimmers at a 56 59 beach, this value is not MONROE 0 0 0 to be exceeded on any single day. WEST COAST EAST COAST SOURCES: Florida Department of Environmental Protection; mapline.com

Figure 6

EVERGLADESFOUNDATION.ORG RED TIDE Q&A to utilizing nutrients derived from the water, the plant-like organism that is responsible for red tide can also act as an Did pollution from the Everglades Agricultural Area animal, deriving nutrition by consuming smaller organisms, (South of Lake Okeechobee) trigger the recent red including bacteria and small blue-green algae that may also tide blooms? No. The red tide began offshore prior to the have been fueled by discharges. Red tide is also known to estuary releases, just after the passage of Hurricane Irma. indirectly derive nutrients from dead and decomposing fish— literally feeding off the organisms that have succumbed to its Do high flows into the estuaries sustain the red tide brevetoxins14. blooms and make them worse? Yes. It is likely no coincidence that the most intense area of the current So, what’s the solution? We need to restore the flow of red tide is near the outlet to Charlotte Harbor and the water from Lake Okeechobee back to the Everglades and Caloosahatchee River. The Heil et al. 2014 study has shown reduce nutrient loads to our waterways, particularly from that such a massive, local source of nutrients can meet much agriculture. Everywhere. or even all of the red tide’s demand as it moves inshore11. These researchers found that nutrients derived from the BLUE-GREEN ALGAE BLOOM Caloosahatchee River in 2005 (a high discharge year) could account for 100% of nutrient demand of the red tide within The frequency and duration of blue-green algae blooms (and the lower estuarine zone, and for 13 and 30% of the N and other types of algae blooms) are increasing both globally and P demand of a red tide in nearshore areas. Other “local” locally. And like the red tide, blue-green algae blooms need sources of nutrients would be needed to maintain blooms substantial quantities of nitrogen and phosphorus as fuel for up-coast (e.g., Sarasota Bay) or down-coast (e.g., near growth and maintenance of the bloom. While red tide thrives Naples) of the Caloosahatchee as dictated by the intensity in salt water, there is a freshwater blue-green algae bloom of the bloom. Nutrient demand is relative to bloom intensity, that is also occurring in Lake Okeechobee and along the St. and intense blooms depend on multiple, diverse sources as Lucie and Caloosahatchee rivers, compounding the problem. they move closer to shore. Blue-green algae, or cyanobacteria, is actually a How much of the nutrients that could be fueling this photosynthesizing bacteria and found in some of the oldest bloom come from the Lake? According to the Florida fossils on Earth. The species we typically see blooming Department of Environmental Protection (FDEP)12, about in south Florida freshwater environments (Microcystis 61% of the nitrogen in the lower Caloosahatchee comes from aeruginosa) gets a lot of attention because it can produce Lake Okeechobee, and the remainder from local urban and dangerous toxins (called microcystin toxin) that harm the agricultural sources. During a similarly wet condition in Water liver and may affect neural function. See The Everglades Year 2011, Lake Okeechobee discharges contributed 69% of Foundation Fact Sheet on this toxin (attached). the total nitrogen and 50% of the total phosphorus to the St. Lucie. During the same year, Lake Okeechobee discharges In 2018, extremely high levels of microcystin toxin have been contributed 55% of the total nitrogen and 40% of the total measured all along the Caloosahatchee and St. Lucie Rivers phosphorus to the Caloosahatchee estuary13. (Figure 6). The US EPA has recommended 4 micrograms per liter of microcystins as the uppermost value that is Will reducing nutrient pollution locally help? In general, considered safe primary contact recreation. This value should reduction of nutrient pollution is essential to protecting our not be exceeded on any single day to protect swimmers at aquatic environments and coastal habitats across South a beach. During the last 75 days, the Florida Department of Florida…and the entire planet. Management strategies that Environmental Protection measured levels more than 100 reduce nutrient loads (especially N and P) to coastal waters times that threshold at some locations, and all sampling will not prevent red tide from forming along the Florida Shelf. locations are above the safe, 4 micrograms per liter limit. However, nutrient reduction will help reduce the intensity and duration of red tide events, especially as these blooms BLUE-GREEN ALGAE BLOOM Q&A of algae move closer to shore and require additional, local sources of nutrients. Are the blue-green algae blooms in the Caloosahatchee and St. Lucie Rivers related to Lake Okeechobee How much of the red tide is caused by local sources releases? Yes. Unlike red tide, the blue-green algae blooms and how much is related to other factors? Environmental we are experiencing are associated with a freshwater species conditions (salinity, temperature, wind pattern, circulation, etc.) that thrives in warm, phosphorus-rich water. So, the blooms and sources of nutrients that trigger red tide formation along in the Caloosahatchee and St. Lucie Estuaries are almost the Florida Shelf have been identified and are unrelated to certainly triggered by releases from Lake Okeechobee and land-based sources of nutrients. However, as red tide moves inflows from the local basins and sustained by the high nearer to shore, a variety of land-based sources of nutrients nutrient load and optimal salinity conditions provided by such as those associated with Lake Okeechobee discharges continued discharges. can play a role in bloom maintenance (see above). In addition

EVERGLADESFOUNDATION.ORG Where is the pollution coming from? The data for this The Total Maximum Daily Load for Lake Okeechobee season is not yet available. However, during a similar wet adopted in Florida statute is 105 metric tons from all surface condition to this season, Water Year 2011, Lake Okeechobee water sources into Lake Okeechobee. In Water Year discharges contributed 69% of the total nitrogen and 50% 2018, the Florida Department of Environmental Protection of the total phosphorus to the St. Lucie. During the same measured 1,046 metric tons of P into Lake Okeechobee. year, Lake Okeechobee discharges contributed 55% of Approximately 70 metric tons of P, or about 7% of the total the total nitrogen and 40% of the total phosphorus to the came from the Everglades Agricultural Area. The last 5-year Caloosahatchee15. average P loading into the Lake is around 633 metric tons, about 6 times the Total Maximum Daily Load limit. During What is the role of the Everglades Agricultural Area in Water Year 2018, 7,512 metric tons of N reached Lake Lake Okeechobee pollution? According to the University of Okeechobee with 1,043 metric tons of N (or about 14% Florida researchers, there are more than 36,440 metric tons of the total) came from the Everglades Agricultural Area excess phosphorus stored in Lake Okeechobee sediments16. (Figure 7)18.

Figure 7: Total phosphorus (TP) and nitrogen (TN) contribution to Lake Okeechobee in WY 2018 (Source: FDEP18).

This figure represents the integrated contributions from all What about septic tanks? In general, septic tanks should sources, both from the Everglades Agricultural Area (which be discontinued and replaced with central sewers. Monroe contributed to these sediments by back-pumping into County, for example, spent $1 billion on removing septic Lake Okeechobee) and contributing basins north of Lake tanks, and the improvements to nearshore water quality Okeechobee. The Everglades Foundation is investigating the have been significant. This issue is particularly acute for phosphorus sources in the sediments and will be publishing the Indian River Lagoon, though a relatively small problem the results soon. It appears that during the backpumping era, in Martin County. Even those who espouse septic tanks as the Everglades Agricultural Area contributed up to 40% of the the problem have written that the most serious problems in total phosphorus loading to the Lake (WY 1982). Martin County are associated with the Lake Okeechobee discharge events. The freshwater blue-green algae blooms Peer-reviewed research estimates that legacy P in Lake in the St. Lucie and Caloosahatchee Rivers are definitely Okeechobee sediment is acting (and will continue to act) linked to Lake Okeechobee releases rather than a chronic as an internal source of P leaching into Lake Okeechobee poor water quality that would result from a problem primarily water – thus contributing to pollution discharges to the related to septic tanks. Caloosahatchee and St. Lucie – for 12-31 years13. Research also shows that the highest rates of net P sedimentation in Lake Okeechobee were coincident with the era of the EAA back-pumping into Lake Okeechobee in the 1970s. Net P sedimentation has declined since, as the system likely became saturated17. As a testament to the extent of P pollution remaining in the EAA, this area comprises only about 15% of the Everglades land area south of Lake Okeechobee, yet the EAA represents about 61% of the stored P and contributes 170 metric tons of P to the water conservation areas.

EVERGLADESFOUNDATION.ORG SOURCES

1Glibert, P.M., Seitzinger, S., Heil, C.A., Burkholder, J.M., Parrow, M.W., Codispoti, L.A., Kelly, C. 2005. The role of eutrophication in the global proliferation of harmful algal blooms: new perspectives and approaches. Oceanography 18, 196–207.

2Steffen, W., Richardson, K., Rockstrom, J., Cornell, A. E., Fetzer, I., Bennett, E. M., Biggs, R., Carpenter, S. R., deWries, W., deWit, C. A., Folke, C., Gertne, D., Heinke, J., Mace, G. M., Persson, L. M., Ramanathan, V., Reyers, B., Sorlin, S. 2015. Planetary boundaries. Guiding human development on a changing planet. Science, Jan 15, 2015, 1259855.

3Mekonnen, M. M., Hoekstra, A. Y. 2018. Global anthropogenic phosphorus loads to freshwater and associated grey water footprints and water pollution levels: A high-resolution global study. Water Resources Research 54, 345-358.

4Dunan, E., Kleinman, P. JA., Sharpley, A. N. 2012. Eutrophication of Lakes and Rivers. In: eLS. John Wiley & Sons, Ltd: Chichester.

5Howarth, R.W. 2008. Coastal nitrogen pollution: a review of sources and trends globally and regionally. Harmful Algae. https://doi. org/10.1016/j.hal.2008.08.015

Carpenter, S.R. and E.M. Bennett. 2011. Reconsideration of the planetary boundary for phosphorus. Environmental Research Letters. 6 014009

Cordell, D., A. Rosemarin, J.J. Schroder, A.L. Smit. 2011. Towards global phosphorus security: A systems framework for phosphorus recovery and reuse options. Chemosphere. 84: 747-758.

6U.S. EPA. 2015. A compilation of cost data associated with the impacts and control of nutrient pollution. U.S. EPA Office of Water. EPA 820-F-15-096. 110 pages.

7Kadlec, R.H., Knight, R.L., 1996. Treatment Wetlands. CRC/ Lewis Publishers, Boca Raton, FL, USA.

8Weisberg, R.H., L. Zheng, Y. Liu, A.A. Corcoran, C. Lembke, C. Hu, J.M. Lenes, J.J. Walsh. 2016. Karenia brevis blooms on the West Florida Shelf: A comparative study of the robust 2012 bloom and the nearly null 2013 event. Continental Shelf Research. 120: 106-121.

9Heil, C.A. and 15 others. 2014. Blooms of Karenia brevis (Davis) G. Hansen & Ø. Moestrup on the West Florida Shelf: Nutrient sources and potential management strategies based on a multi-year regional study. Harmful Algae. 38:127-140.

10C. Heil, personal communication, September 13, 2018.

11Heil, C.A. and 15 others. 2014. Blooms of Karenia brevis (Davis) G. Hansen & Ø. Moestrup on the West Florida Shelf: Nutrient sources and potential management strategies based on a multi-year regional study. Harmful Algae. 38:127-140.

12FDEP, 2012. Final Basin Management Action Plan for the Implementation of Total Maximum Daily Loads for Nutrients Adopted by the Florida Department of Environmental Protection in the Caloosahatchee Estuary Basin.

13South Florida water Management District, South Florida Environmental Report. 2013. Chapter 10: Coastal Priorities.

14Killberg-Thoreson, L., R.E. Sipler, C.A. Heil, M.J. Garrett, Q.N. Roberts, D.A. Bronk. 2014. Nutrients released from decaying fish support microbial growth in the eastern Gulf of Mexico. Harmful Algae. 38:40-49.

15South Florida water Management District, South Florida Environmental Report. 2013. Chapter 10: Coastal Priorities.

16Reddy. K. R., Newman, S., Osborne, T. Z., White, J. R., Fitz, H. C. 2011. Phosphorus Cycling in the Greater Everglades Ecosystem: Legacy Phosphorus Implications for Management and Restoration. Critical Reviews in Environmental Science and Technology 41(S1), 149-186.

17Havens et al. 2005. Chapter 10 in the South Florida Environmental Report. South Florida Water Management District.

18Florida Department of Environmental Protection. (2018). Personal communications, Meeting with the Everglades Foundation staff, August 29, 2018.

19Lapointe, B. L. Herren and B. Bedford. Effects of Hurricanes, Land Use, and Water Management on Nutrient and Microbial Pollution: St. Lucie Estuary, Southeast Florida. Journal of Coastal Research, Vol. 28, No. 6, pp.1345-1361, November, 2012. Authors write, e.g., (p.1356) “The overriding importance of the post hurricane discharges via the C-44 in the water-quality degradation of the SLE was evident in our study.” ABOUT THE AUTHORS

MELODIE NAJA, PH.D. Dr. Naja is the Director of the Science Department at The Everglades Foundation, where she leads a multi- disciplinary team of water quality scientists, ecologists, hydrologists, engineers, and an economist. She is an expert in water quality modeling and analytical chemistry. She holds a doctorate in Physical Chemistry from Henri Poincaré University, Nancy, France.

STEPHEN DAVIS, PH.D. Dr. Davis is the Senior Ecologist at The Everglades Foundation. A native of Ohio, he earned a Ph.D. from Florida International University in 1999 with research in and the coastal Everglades. He draws upon his 20+ years of Everglades research experience, including 10 years as professor of wetland ecology at Texas A&M University, to lead science and science communication efforts focused on Everglades ecosystem health, restoration planning, and impacts of sea-level rise.

THOMAS VAN LENT, PH.D. Dr. Van Lent is the Vice President of Science and Education at The Everglades Foundation. He has 35 years of experience on Everglades water quantity and quality investigations, primarily diagnosing and solving hydrologic and water quality problems in the Everglades. He holds a doctorate in Civil Engineering from Stanford University.

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