Brian E. Lapointe

Florida Atlantic University | FAU · Harbor Branch Oceanographic Institute

Nitrogen (N) loading can affect estuarine food webs through alteration of primary producers. In the Indian River Lagoon (IRL), Florida there has been long-term N enrichment, worsening phytoplankton blooms, large-scale macroalgal blooms, and catastrophic seagrass losses. To investigate how N enrichment affects higher trophic levels and food webs in...

In Florida's Indian River Lagoon (IRL), anthropogenic eutrophication has resulted in harmful algal blooms and catastrophic seagrass losses. Hoping to improve water quality, policy makers enacted fertilizer bans, assuming that this would reduce the nitrogen (N) load. To assess the effectiveness of these bans, seawater and macroalgal samples were col...

The coastal communities of Lee County, Florida, USA have grown rapidly since the 1970s. In this county, drainage ditches, canals, creeks, and the Caloosahatchee River Estuary often have high concentrations of nutrients and bacteria limiting their designated uses. Septic systems have previously been identified as a major pollution source in some are...

Blooms of various types of seaweeds have been reported worldwide, with recent expansions in surface waters. While most of the expansions have been attributed to eutrophication due mainly to human activities, any potential role of climate change is unclear. Here we show that, in the East China Sea and Yellow Sea, increased biomass of Sargassum horne...

Wastewater management is a critical issue globally. In Florida, the importance of this issue is heightened by the proximity to sensitive ecosystems. Distributed wastewater treatment units (DWTU) are a recent, state-approved alternative to septic system conversions to centralized sewer infrastructure. In this study, the performance of a DWTU was tes...

As human population growth has expanded in Southwest Florida, water quality has become degraded with an increased occurrence of harmful algal blooms (HABs). Red tide (Karenia brevis) originating offshore, intensifies in nearshore waters along Florida's Gulf Coast, and blue-green algae (Microcystis spp.) originating in Lake Okeechobee is discharged...

Coral reefs are facing a constant barrage of human impacts, including eutrophication, overharvesting and climate change. However, research and management are just beginning to depart from a single-dominant-stressor paradigm and a holistic ecosystem-based understanding of these systems is still in its infancy. We expand on a well-known theoretical m...

This datasheet on Gracilaria tikvahiae covers Identity, Overview, Distribution, Dispersal, Diagnosis, Biology & Ecology, Environmental Requirements, Impacts, Uses, Further Information.

Effluent from septic systems can pollute groundwater and surface waters in coastal watersheds. These effects are unknown for the highly urbanized central Indian River Lagoon (CIRL), Florida, where septic systems represent > 50% of wastewater disposal. To better understand these impacts, water quality was assessed along both canals and a tributary t...

Macroalgal blooms are increasing on the Belize Barrier Reef (BBR) as scleractinian coral cover declines. Although some have attributed this to reduced grazing, the role of land-based nutrient pollution has not been assessed. Nutrient enrichment was quantified through macroalgal tissue analysis from Belize City to the offshore fore reef and at sever...

The Global Harmful Algal Blooms (GlobalHAB, www.global hab.info) Program is aimed at fostering international cooperative research directed toward improving the prediction of harmful algal bloom (HAB) events in aquatic ecosystems, and providing sound knowledge for policy- and decision-making to manage and mitigate HAB impacts in a changing planet. G...

The pelagic brown macroalgae Sargassum spp. have grown for centuries in oligotrophic waters of the North Atlantic Ocean supported by natural nutrient sources, such as excretions from associated fishes and invertebrates, upwelling, and N2 fixation. Using a unique historical baseline, we show that since the 1980s the tissue %N of Sargassum spp. has i...

Harmful algal blooms that can produce toxins are common in the Indian River Lagoon (IRL), which covers ~250 km of Florida's east coast. The current study assessed the dynamics of microcystins and saxitoxin in six segments of the IRL: Banana River Lagoon (BRL), Mosquito Lagoon (ML), Northern IRL (NIRL), Central IRL (CIRL), Southern IRL (SIRL), and t...

The extensive blooms of the pelagic Sargassum in the Atlantic raised the question of whether this brown seaweed may play an important role in climate change mitigation through carbon fixation and carbon sequestration, as argued in several recent papers. Using simple calculations and published values on Sargassum coverage, biomass density, carbon/bi...

Almost 50 years ago, Michael Rosenzweig pointed out that nutrient addition can destabilise food webs, leading to loss of species and reduced ecosystem function through the paradox of enrichment. Around the same time, David Tilman demonstrated that increased nutrient loading would also be expected to cause competitive exclusion leading to deleteriou...

The AdjustaDepth TechnoEconomic Analysis was prepared by Mark E. Capron PE, Co-PI, under the direction of Kelly Lucas, PhD, PI and submitted April 3, 2019 to U.S. Department of Energy ARPA-E under Phase 1 Contract DE-AR0000916. Its 33 tabs present the cost and yield projections for growing Gracilaria tikvahiae in the Gulf of Mexico. It can be adapt...

The comment by Julian (2020) criticizes aspects of our paper, “Nitrogen enrichment, altered stoichiometry, and coral reef decline at Looe Key, Florida Keys, USA.” The comment begins by misrepresenting our extensive literature review, while providing no justification for the claim of a “skewed reading.” Julian’s critique focused on methods of data h...

Almost 50 years ago, Michael Rosenzweig pointed out that nutrient addition can destabilize food webs, leading to loss of species and reduced ecosystem function through the paradox of enrichment. Around the same time, David Tilman demonstrated that increased nutrient loading would also be expected to cause competitive exclusion leading to deleteriou...

Historically, extensive seagrass meadows were common throughout the Indian River Lagoon (IRL) in east-central Florida, USA. Between 2011 and 2017, widespread catastrophic seagrass losses (~95%) occurred in the IRL following unprecedented harmful algal blooms (HABs), including persistent brown tides (Aureoumbra lagunensis). Little is known about how...

Increased loadings of nitrogen (N) from fertilizers, top soil, sewage, and atmospheric deposition are important drivers of eutrophication in coastal waters globally. Monitoring seawater and macroalgae can reveal long-term changes in N and phosphorus (P) availability and N:P stoichiometry that are critical to understanding the global crisis of coral...

The biggest bloom Floating mats of Sargassum seaweed in the center of the North Atlantic were first reported by Christopher Columbus in the 15th century. These mats, although abundant, have until recently been limited and discontinuous. However, Wang et al. report that, since 2011, the mats have increased in density and aerial extent to generate a...

Observations from patch reef and fore-reef benthic surveys highlight that the original main structural components of living corals (Acropora spp., Siderastrea spp. and Orbicella spp.) are in decline with much of the hard bottom habitats, including coral skeletons, now dominated by fleshy macroalgae (Dictyota sp., Lobophora sp.) as well as several e...

Compared with our understanding of most aspects of sea turtle biology, knowledge of the surface-pelagic juvenile life stages remains limited. Young North Atlantic cheloniids (hard-shelled sea turtles) are closely associated with surface-pelagic drift communities (SPDCs), which are dominated by macroalgae of the genus Sargassum. We quantified SPDCs...

Field and laboratory experiments are designed to measure Sargassum biomass per area (density), surface reflectance, nutrient contents, and pigment concentrations. An alternative floating algae index-biomass density model is established to link the spectral reflectance to Sargassum biomass density, with a relative uncertainty of ~12%. Monthly mean i...

Macroalgae are a natural, common feature of inland waters as well as estuaries, coastal waters, and oceanic waters particularly the Gulf of Mexico, North Atlantic Ocean, and Caribbean Sea where pelagic Sargassum is distributed. As the causes and effects of macroalgal blooms are similar in many ways to those associated with harmful phytoplankton spe...

Nutrient enrichment is a significant global-scale driver of change in coastal waters, contributing to an array of problems in coastal ecosystems. The St. Lucie Estuary (SLE) in southeast Florida has received national attention as a result of its poor water quality (elevated nutrient concentrations and fecal bacteria counts), recurring toxic Microcy...

Responses of Halimeda macroloba to growth and chemical concentrations when encountering elevated nutrient concentrations were experimentally tested in the subtidal zone. To determine the effect of nutrients, algae were fertilized using Osmocote® a slow-release fertilizer; the concentrations of nitrogen and phosphorus were enriched. A total of four...

The Sargassum Watch System processes satellite data and feeds results to a Web portal, giving decision makers timely information on seaweed location and warnings for potential beaching events.

In intertidal zones, tidal cycles reduce water depths and provide areas of shallow water where wading birds can forage for aquatic prey (water depths 0-50 cm). However, a bird that forages diurnally can make use of only a portion of the tidal cycle, which can limit fulfillment of energetic demands. Furthermore, daily and biweekly (spring-neap) tide...

Nutrient enrichment continues to disrupt marine ecosystem function worldwide. Assessing eutrophication in seagrass ecosystems such as the Great White Heron National Wildlife Refuge (GWHNWR), Florida Keys is critical for protecting the diverse community that depends on the intertidal and subtidal seagrass beds. We quantified water column nutrients,...

We tested the relative effects of physical factors such as exposure time and water depth as well as nutrient availability on Thalassia testudinum, Halodule wrightii and Syringodium filiforme distribution within the Great White Heron National Wildlife Refuge, Florida Keys. We quantified the percent cover of each seagrass species in 1-m2 plots (n = 3...

Long-term monitoring data show that hard coral cover on the Great Barrier Reef (GBR) has reduced by >70 % over the past century. Although authorities and many marine scientists were in denial for many years, it is now widely accepted that this reduction is largely attributable to the chronic state of eutrophication that exists throughout most of th...

The effect of nutrient enrichment on the growth and chemical concentrations of two different algal life strategies, Halimeda macroloba and Turbinaria conoides were assessed to test the predictions of the Carbon-Nutrient Balance Hypothesis (CNBH). We concluded that nutrient enrichment had no strong effects on the growth but had a direct effect on th...

The effects of nutrient enrichment and herbivory on resource allocation patterns among morphology, reproduction, and chemical content of the brown alga, Turbinaria conoides (J. Agardh) Kützing were tested in the shallow subtidal zone of the Gulf of Thailand. The field experimental design comprised 36 plots (50 ¥ 50 cm2) with and without herbivores,...

Optical data collected in coastal waters off South Florida and in the Caribbean Sea between January 2009 and December 2010 were used to evaluate products derived with three bio-optical inversion algorithms applied to MODIS/Aqua, MODIS/Terra, and SeaWiFS satellite observations. The products included the diffuse attenuation coefficient at 490nm (Kd_4...

A "black water" event, as observed from satellites, occurred off southwest Florida in 2012. Satellite observations suggested that the event started in early January and ended in mid-April 2012. The black water patch formed off central west Florida and advected southward towards Florida Bay and the Florida Keys with the shelf circulation, which was...

Multiple hurricanes impacted southeast Florida during 2004 and 2005, producing record rainfall and large-scale stormwater runoff into the urbanized St. Lucie Estuary (SLE). To assess effects on water quality, field samples were taken in June and November 2005 and March 2006 along the SLE's three main segments: the South Fork, connected via the C-44...

Lapointe, B.E.; Herren, L.W., and Bedford, B.J., 2012. Effects of hurricanes, land use, and water management on nutrient and microbial pollution: St. Lucie Estuary, southeast Florida. Multiple hurricanes impacted southeast Florida during 2004 and 2005, producing record rainfall and large-scale stormwater runoff into the urbanized St. Lucie Estuary...

The questions on how Halimeda macroloba allocates resources to growth and sexual reproduction when encountering herbivores and elevated nutrient concentrations were experimentally examined in the natural subtidal zone and in water tanks. The field experimental design comprised 96 plots (50�50 cm2), with and without herbivores, and two nutrient leve...

Abstract Halimeda macroloba Decaisne is a reef builder that provides habitats for many marine organisms and is important for the production of calcium carbonate sediments. This species is one of the most common and abundant algae in tropical regions of the Indo-Pacific Ocean. However, the trigger for reproduction of H. macroloba is not well underst...

Coral reefs in the Negril Marine Park (NMP), Jamaica, have been increasingly impacted by nutrient pollution and macroalgal blooms following decades of intensive development as a major tourist destination. A baseline survey of DIN and SRP concentrations, C:N:P and stable nitrogen isotope ratios (δ15N) of abundant reef macroalgae on shallow and deep...

Tobago's fringing coral reefs (FR) and Buccoo Reef Complex (BRC) can be affected locally by wastewater and stormwater, and regionally by the Orinoco River. In 2001, seasonal effects of these inputs on water-column nutrients and phytoplankton (Chl a), macroalgal C:N:P and delta(15)N values, and biocover at FR and BRC sites were examined. Dissolved i...

Stable nitrogen isotope (delta(15)N) analysis has proven an effective "fingerprint" of sewage contamination in coral reef environments; however, short-term variability in nitrogen cycling and isotopic fractionation may obscure long-term trends. Here, we examine delta(15)N signatures in the organic endoskeletons of long-lived (20-40 years) gorgonian...

Coral reefs off southeast Florida have experienced an unprecedented succession of invasive chlorophyte blooms over the past two decades, most recently the non-native Caulerpa brachypus f. parvifolia. To better understand the ecology and nutrition of the C. brachypus invasion, we monitored benthic cover, water column dissolved inorganic nutrients, t...

While coral reefs decline, scientists argue, and effective strategies to manage land-based pollution lag behind the extent of the problem. There is need for objective, cost-effective, assessment methods. The measurement of stable nitrogen isotope ratios, delta(15)N, in tissues of reef organisms shows promise as an indicator of sewage stress. The ch...

A pilot-plant scale waste recycling-mariculture system was developed at the Woods Hole Oceanographic Institution's Environmental Systems Laboratory in 1973. Basically, the concept of this system is to grow unicellular marine algae in continuous flow cultures on mixtures of seawater and secondarily treated sewage effluent, and feed the algae to biva...

A massive outbreak of Karenia brevis that had been ongoing for several months along the southwestern coast of Florida was sampled in early September 2005 off Sanibel Island to assess the utility of bio-optical features and ataxonomic analysis (quantification of eukaryotic and cyanobacterial picoplankton) by flow cytometry in monitoring red tide blo...

Coral reefs of Martinique have undergone an excessive growth of macroalgae over the past two decades, leading to a decrease in coral cover and health status. Increasing urbanization, agricultural and industrial activities over the South coast of Martinique have raised land-based nutrients discharges. In this study we used macrophytes ä15N signature...

The combined effects of light intensity and nitrogen (NO3−) on growth rate, pigment content, and biochemical composition of Gracilaria foliifera v. angustissima (Harvey) Taylor was investigated using outdoor continuous cultures. Growth of Gracilaria increased linearly with increasing light to 0.43 doublings d−1 at high light levels (383 ly d−1 of i...

The results from the multimillion dollar Enrichment of Nutrients on Coral Reefs Experiment (ENCORE) on One Tree Island Reef (OTIR) suggest that increased nutrient loads to coral reefs will have little or no effect on the algal growth rates and, hence, on the associated effects that increased algal growth might have on the functioning and stability...

Macroalgal blooms have increased globally in recent decades as a result of increased nutrient enrichment and eutrophication of coastal waters. In Lee County, Florida, this problem reached a critical stage in 2003/2004 when massive rhodophyte blooms washed ashore, making beaches unsuitable for recreation and requiring an expensive removal program. T...

Coral reefs worldwide are under stress from a variety of anthropogenic activities that can alter or inhibit recovery from catastrophic physical disturbances such as hurricanes. On coral reefs off southeast Florida, land-based nutrient pollution contributed to a successful invasion ofCaulerpa brachypus fornaparvifolia that dominated (up to 90% cover...

The results reported in this paper demonstrate suboptimal experimental designs in some of the previously published manipulative methods and provide insights for the improvement of in-situ nutrient studies on coral reefs. Overgrown 0.5-liter porous clay-pot diffusers (“mini-reefs”—following a decade of recruitment, colonization and competition) were...

Over the past several decades, the fixation of "new" nitrogen to the biosphere has doubled. For the early 21st century, the most significant rate increases in atmospheric nitrogen deposition are predicted for developing nations. Wet nitrogen deposition was assessed on the remote island of Green Turtle Cay, Bahamas in a dry and wet season from Janua...

Since 1990, coral reefs off southeast Florida have experienced an unprecedented succession of macroalgal blooms and invasions. To determine if anthropogenic land-based nitrogen (N) sources support these HABs, we collected macroalgal tissue for stable nitrogen isotope (δ¹⁵N) analysis at three spatially distinct depths ranging from the shallow subtid...

Invasive blooms of the siphonaceous green algae Codium spp. have been considered a symptom of coastal eutrophication but, to date, only limited biochemical evidence supports a linkage to land-based nutrient pollution. Beginning in the summer of 1990, spectacular blooms of unattached Codium isthmocladum developed on deep coral reef habitats in south...

The genus Caulerpa is known for its invasion of tropical, subtropical, and temperate coastal waters. Whereas the role of humans as vectors for the introduction of Caulerpa has been well documented, other anthropogenic factors that may mediate the success of an invasion are poorly under- stood. We provide evidence that a recent invasion of Caulerpa...

The main effects and interactions between light (Io, full incident sunlight to 0.07 Io) and NO3− loading (0.4 to 4.3 mmol · g dry weight−1· d−1) on growth rate, photosynthesis and biochemical constituents of Gracilaria tikvahiae McLachlan were studied using a factorial design experiment in outdoor, continuous-flow seawater cultures. Incipient nitro...

Land-based nutrient pollution represents a significant human threat to coral reefs globally. We examined this phenomenon in shallow seagrass and coral reef communities between the Content Keys (southern Florida Bay) and Looe Key (south of Big Pine Key) in the Lower Florida Keys by quantifying the role of physical forcing (rainfall, wind, tides) and...

Evidence suggests that marine herbivores select for prey items with elevated nitrogen content. We tested this hypothesis with experimental growth studies of the herbivorous gastropod Aplysia californica offered diets of the rhodophyte Gracilaria ferox with varying nitrogen content. A. californica had a sevenfold feeding preference by weight for G....

In studies of primary production of the open ocean, the measurement of new production is often considered a measure of the degree of eutrophication. Because of new research this is questionable, which in our opinion, calls for a refinement to the original concept. We believe that the measure of variable fluorescence is pivotal to a new understandin...

The simultaneous effects of grazing and nutrient enrichment on macroalgal communities were experimentally investigated using plastic mesh enclosure/exclosure cages along a natural nutrient (DIN, SRP) gradient from the discharge of a tidal mangrove creek on the west side of Norman's Pond Cay, Exumas Cays, Bahamas. Nutrient enrichment was the only fa...

Reef-building corals throughout the world are considered endangered. The evidence is a decline in coral health and reduced coral cover. Competing hypotheses for the cause of coral loss include removal of grazers, nutrient enrichment, disease, coral bleaching, increase in temperature, and excess light/ultraviolet exposure. We suggest that light limi...