Recently, Dr. Lapointe and Lab Chemistry Coordinator Lynn Wilking conducted a sampling expedition to collect pelagic Sargassum macroalgae offshore of the lower Florida Keys. Pelagic Sargassum serve as an ecologically important habitat for many marine animals, however excessive beaching of this seaweed has become an increasing nuisance since 2011. Sargassum may also affect the ocean’s biogeochemistry through modulating nutrient cycles and releasing colored dissolved organic matter. However, to date, except for a handful of studies, our knowledge in these areas is only next to nil. In conjunction our collaborator, Dr. Chuanmin Hu, from the University of South Florida we are working to better understand the distribution and abundance of pelagic Sargassum and the linkages with environmental changes in the Intra-Americas Sea and Tropical Atlantic.
Ryther revisited: Nutrient excretions by fishes enhance productivity of pelagic Sargassum in the western North Atlantic Ocean
Dr. Lapointe was invited by the Wildlife Conservation Society to return to Belize, where he conducted seminal research on the effects of nutrient enrichment on coral reefs in the 1980s and early 1990s. During this trip, he and Wildlife Conservation Society staff collected water samples of groundwater and rainfall at Glover's Reef Research Station. Macroalgae were collected at a variety of sites, including Glover's Reef, Curlew Reef, Tobacco Reef, Twin Cays, and Man-O-War Cay (seabird rookery), for elemental and stable isotope analysis. These samples will be compared with the historic samples Dr. Lapointe collected in the 1980s to see of how nutrient content of macroalgae have changed over the last 20 years. These data will help scientists and resource managers better understand the mechanisms causing the ongoing macroalgal blooms plaguing the Belize Barrier Reef Complex. Dr. Lapointe plans to present the results of this restudy in November at the 2017 Gulf and Caribbean Fisheries Institute meeting in Mérida, Yucatan, Mexico. Links to related research in Belize by Dr. Lapointe below.
Macroalgal overgrowth of fringing coral reefs at Discovery Bay, Jamaica: Bottom-up versus top-down control
A comparison of nutrient-limited productivity in macroalgae from a Caribean barrier reef and from a mangrove ecosystem
Dr. Lapointe & Research Coordinator, Rachel Brewton, traveled to the Florida Keys to dive at Looe Key to film an outreach news segment about Looe Key National Marine Sanctuary with Jay Cashmere of WPTV. Dr. Lapointe discussed his long-term monitoring program at Looe Key and changes he has observed on the reef over the last 30 years.
Brian & Rachel stayed at Dr. Lapointe's lab on Big Pine Key during the quick trip and managed to squeeze in a sunset paddle before heading back to Fort Pierce.
Dr. Lapointe presented "Evidence of Wastewater-Driven Eutrophication and Harmful Algal Blooms in the Indian River Lagoon, East-Central, Florida" at the 93rd Florida Annual Meeting and Exposition (FAME) hosted by the Florida Section of the American Chemical Society at the Innisbrook Resort in Palm Harbor, FL.
EVIDENCE OF WASTEWATER-DRIVEN EUTROPHICATION
AND HARMFUL ALGAL BLOOMS IN THE INDIAN RIVER LAGOON, EAST-CENTRAL FLORIDA
Dr. Brian E. Lapointe
ABSTRACT: The Indian River Lagoon (IRL) has experienced problems associated with increasing macroalgal blooms, seagrass epiphytization, and hypoxia/anoxia for decades. Following significant rainfall in Spring 2011 that ended a multi-year drought, a severe “super bloom” of phytoplankton (> 100 µg/L Chl a) developed in the northern IRL. This was followed by a “brown tide” in the northern IRL and Mosquito Lagoon in 2012, which was followed by widespread seagrass die-off and wildlife mortality, including endangered manatees. To better understand the nutrient source(s) and dynamics surrounding these harmful algal blooms (HABs), seawater samples and benthic macroalgae were collected at a network of 20 stations throughout the IRL. High TDN concentrations (up to 152 µM) and TDN:TDP ratios (>100:1) in the poorly flushed northern IRL, Mosquito Lagoon and Banana River segments reflected the accumulation and cycling of N-rich groundwater and surface water inputs that produce P- limitation. Macroalgae d15N values were enriched throughout the IRL (+6.3 o/oo) and similar to values reported for macroalgae from other sewage-polluted coastal waters. Because point-source sewage inputs to the IRL were largely eliminated through the IRL Act of 1990, these results suggest that non-point source N enrichment from septic tanks (300,000-600,000) represents a significant and largely ignored N-source to the IRL. The high degree of sewage N contamination of the IRL, combined with recent HABs, including toxic ecotypes of the red macroalga Gracilaria tikvahiae McLachlan, seagrass loss, and wildlife mortality, indicates a critical need for improved sewage collection and treatment, including nutrient removal.
Lapointe, Kaiser, & Kane Present at the joint Southeastern Estuarine Research Society & Benthic Ecology Meeting in Myrtle Beach, SC
Dr. Lapointe, Bret Kaiser, and Katherine Kane traveled to Myrtle Beach, SC to present their research at the joint Southeastern Estuarine Research Society & Benthic Ecology Meeting.
Dr. Lapointe traveled to Pointe-à-Pitre, Guadeloupe in the French Caribbean to present a lecture entitled, "The role of nutrients in coral-algal phase-shifts: lessons from the Caribbean region" at the LabEx <<CORAIL>> Workshop on March 24 & 25, 2017 hosted by the Université des Antilles, laboratoire de Biologie Marine. Dr. Lapointe was honored to be invited to speak to the symposium about human impacts to coral reefs.
The role of nutrients in coral-algal phase-shifts: lessons from the Caribbean region by B.E. Lapointe
Since the 1970s, coral reefs in the Caribbean region have experienced a phase-shift away from dominance by corals and towards macroalgae and algal turfs. Multiple lines of evidence suggest that eutrophication is a major driving force behind the phase-shift, which results from local, regional and global scales of nutrient enrichment. Nutrient threshold research on the Belize Barrier Reef in the 1980s showed that coral reefs are susceptible to very low levels of reactive nitrogen and phosphorus enrichment, above which they shift towards dominance by algae. Experimental laboratory research and case studies of coral-to-algal phase shifts in Martinique, Jamaica, Bahamas, and the Florida Keys supported the nutrient threshold model. However, the algal species composition of the phase-shift is related to various environmental factors that include grazing, sedimentation, temperature, and physical factors such as turbulence. Improved land-use, including best management practices for agriculture and advanced wastewater treatment in urban areas, are needed to moderate this problem and related issues of climate change in the future.
The HAB lab team has been hard at work collecting water and macroalgae samples in the Indian River Lagoon whenever weather has been permitting. As such, we've had some gorgeous days on the water and some freezing ones. We were very excited to finally get HAB lab M.S. student Katherine Kane out on a boat for the first time since she started in the lab last fall. Katherine's thesis research will be investigating how macroalgae responds to varied nutrient treatments in a laboratory setting, so the real-world knowledge she gains collecting macroalgae in the field will serve her well as she progresses in her research!
This week, the HAB lab began collecting water and macroalgae samples in the Indian River Lagoon (IRL). Since 2011, we have been documenting the water quality in the IRL using dissolved nutrient concentrations and the stable isotopes of macroalgae, phytoplankton, and seagrass. This information allows us to determine the sources of pollution within the IRL and to monitor the progress of water quality initiatives, such as fertilizer bans and septic to sewer programs.
HAB Lab M.S. student Bret Kaiser successfully defended his M.S. proposal in a public presentation at Harbor Branch Oceanographic Institute. After his public defense, there was a closed question and answer session where his committee members asked Bret about relevant scientific information and the design of his research. Congratulations to Bret for all his hard work!
HAB Lab members Katherine Kane and Rachel Brewton volunteered at the Manatee Bowl, the Regional Qualifier for the National Ocean Sciences Bowl. Katherine served as a Time Keeper and Rachel was a Score Keeper.
The HAB Lab attended the 2017 Indian River Lagoon (IRL) Symposium at Harbor Branch Oceanographic Institute on February 9, 2017. Graduate student Bret Kaiser presented on his M.S. research that investigates acidification in the IRL and Research Coordinator Rachel Brewton presented on patterns in the stable isotopes of primary producers throughout the IRL.
HAB Lab members Rachel Brewton and Katherine Kane attended the 6th Annual Love Your Lagoon Gala hosted by the Harbor Branch Foundation. The gala raises funds and generates greater awareness of the critical issues in the Indian River Lagoon. Since 2012, this event has raised over $400,000 to support FAU Harbor Branch’s ongoing Indian River Lagoon Observatory research and outreach efforts. At the event, there was a live-auction during which attendees were able to bid on supporting graduate student fellowships, such as those helping to sponsor HAB Lab M.S. students, Katherine Kane and Bret Kaiser. This year's event honored Diane Dunmire Barile, a former professor with Florida Institute of Technology, who has dedicated her career to the study and preservation of the Indian River Lagoon.
On January 25, 2017, Dr. Lapointe spoke to the Florida Senate Appropriations Subcommittee on the Environment and Natural Resources regarding Everglades restoration and effects on downstream estuaries. Citing peer-reviewed scientific literature and case studies from throughout Florida, Lapointe discussed how seed algae from Lake Okeechobee combined with excess nutrients from septic systems and other basin sources fueled algal blooms in the St. Lucie Estuary in the summer of 2016. He also noted the misinformation regarding a connection between the Lake Okeechobee discharges and the brown tide algal bloom in the northern Indian River Lagoon, which was actually related to lagoon-wide effects of nutrient enrichment from wastewater and other basin sources. Finally, Dr. Lapointe cautioned against sending more water south to Florida Bay without ensuring the water would be clean. Major discharge events of “clean water” resulted in low salinities in the 1990s and exacerbated eutrophic conditions already occurring in Florida Bay and the Florida Keys. The ecological impacts included expansion of regional-scale algal blooms (including toxic red tides), low dissolved oxygen, wildlife mortalities, and increased seagrass and coral reef die-off, demonstrating that high salinities were not the cause of these problems. The presentation concluded with a call for sound science to address Florida's water quality issues. Please click the buttons below for more details.
Thank you for checking out the Harbor Branch Oceanographic Institute (HBOI) Harmful Algal Bloom Laboratory (HAB Lab) website! We will be adding in new content continually, so please check back for updates on our current projects and lab news. Additionally, we will be expanding the project pages to include more detailed information on our research.
Studying water quality and harmful algal blooms throughout Florida and the Caribbean.