ASLO Contributed Session.
Lead Organizer: Sandra Lage, CCMAR - Centro de Ciências do Mar (smlage@ualg.pt)
Co-organizers:
Presentations
10:30 AM
FACTORS CRITICAL TO LONG-TERM LAKE AND RESERVOIR MANAGEMENT: RELATIONSHIPS BETWEEN LAND-USE, NUTRIENT LOADING, INFLOWS, HABS AND ANOXIA (7351)
Primary Presenter: Daniel Roelke, Texas A&M University Galveston (droelke@tamu.edu)
Lakes in the southcentral USA are warm-monomictic, many of which have become eutrophic, raising concerns about harmful algal blooms (HABs). HABs associated with prymnesiophytes and cyanobacteria have been recurrently problematic and the frequency, magnitude and duration of HABs are likely to increase with climate change. Here, we seek to better understand the drivers of inland HABs in the southcentral USA, with a particular focus on nitrogen loading. Recent advances in understanding have shown a selection for prymnesiophytes and some toxic cyanobacteria at high N:P ratios. We are sampling twenty reservoirs and their tributaries, spanning a pronounced east-west annual precipitation gradient across Texas. Samplings occur in the spring and summer of each year, and measured parameters include total microcystins, microbial community composition (using metagenomics), microbial functions (using metatranscriptomics), and several water quality parameters. Inflows and nutrient loadings are being determined using the Hydrologic and Water Quality System (HAWQS) calibrated with USGS gauge data and tributary nutrient samples. Principal component analysis reveal a positive relationship between NOx, total microcystins and cyanobacteria taxa that are known microcystin producers. Our finding also suggest a disruption of denitrification during a bloom, providing a possible explanation of high NOx during the bloom. Our work also shows that microcystins can be widespread in these lakes and their tributaries.
10:45 AM
COLLABORATIVE VALUATION OF ECOSYSTEM SERVICES TO INFORM LAKE DECISION-MAKING (4772)
Primary Presenter: Danielle Spence, University of Saskatchewan (danielle.spence@usask.ca)
Cultural eutrophication and harmful algal blooms (HABs) are complex, costly issues facing decision makers. When designed in collaboration with impacted communities, economic valuation of lake ecosystem services (ES) can contribute to informed environmental decision-making by quantifying the economic benefits of lake restoration and understanding the trade-offs people are willing to make amongst ES. In collaboration with the surrounding community, we developed and implemented a discrete choice experiment survey to understand people’s preferences and willingness to pay for restoring a Canadian lake that has been experiencing worsening water quality issues, including more frequent HAB events. Responses to the choice experiment were analyzed using choice models, revealing that the aggregate annual economic benefits of lake restoration across different model specifications ranged from CAD 27 to 55 million, which is substantially greater than estimated costs of lake restoration. Model outputs also reveal that survey respondents had strong preferences for reducing HAB events and for non-use ES such as biodiversity, whereas preferences for recreational fishing were more divided. The results of this study (i) contribute to the growing literature showing substantial benefits to society from restoring lakes and mitigating HABs, and (ii) demonstrate that collaborative valuation techniques are a valuable tool for informing lake decision-making by revealing acceptable trade-offs and priorities amongst lake ES.
11:00 AM
Remote Sensing of Chlorophyll-a as a Measure of Cyanotoxins in San Luis Reservoir, CA (7066)
Primary Presenter: Brittany Lopez Barreto, University of California, Merced (blopezbarreto@ucmerced.edu)
Cyanobacterial harmful algal blooms (cyanoHABs) can harm people, fauna, and affect water quality and recreational use of inland waters. Measuring and monitoring cyanobacteria is limited, while chlorophyll-a (chl-a) is a common water quality metric and has been shown to have a relationship with cyanobacteria. The World Health Organization (WHO) has recently updated their previous 1999 cyanoHAB guidance values (GVs) to be more practical by basing the GVs on chl-a concentration. This creates an opportunity for widespread monitoring of cyanoHABs based on chl-a proxy measures, with satellite remote sensing (SRS) being a potentially powerful tool. This study assessed the comparability of SRS of chl-a for cyanotoxin public health advisories. We used Sentinel-2 and 3 to map chl-a and cyanobacteria, respectively, and classified the values according to WHO GVs. We then compared them to the existing GVs set by the Department of Water Resources (DWR) at San Luis Reservoir, the largest off-stream reservoir in the United States and a key piece of infrastructure in California’s water system. We found mismatches between the SRS-derived WHO 2021 chl-a GV and DWR GVs. However, SRS-based chl-a GVs never missed a bloom detected by the DWR, and warning levels were typically no more than a level off. SRS can help fill temporal data gaps and provide greater spatial information not available from using only in-situ measurements. Using SRS-based chl-a GVs as an early indicator for possible exposure advisories and as a trigger for in-situ sampling may be effective to improve public health warnings.
11:15 AM
SPATIO-TEMPORAL DIVERSITY OF MARINE BENTHIC MATS FROM FLORIDA (7274)
Primary Presenter: David Berthold, University of Florida (dberthold@ufl.edu)
Formation of benthic cyanobacterial mats (BCMs) in marine environments is occurring frequently, partly driven by nutrient loading and climate change. Reports of BCMs occurring on both Florida coasts have increased, from mangroves to seagrass beds and corals, demonstrating a need to understand the diversity involved in the blooms of BCMs. As part of a continued monitoring of this environmental health threat, benthic proliferations were sampled on the Florida coasts between 2021 and 2022. Cyanobacterial mats were collected, eDNA was extracted, and the 16S rRNA of cyanobacteria were amplified using cyanobacterial specific primers. In addition to amplicon sequencing, isolation, characterization, and genome sequencing of select strains were performed. The homocytous filamentous Dapis, Okeania, Salileptolyngbya, and Sirenicapillaria dominated BCMs on the Gulf Coast of Florida. LC-MS/MS analyses revealed high concentrations of anatoxin-a, dihydroanatoxin-a and BMAA and presence of malyngamide C and cylindrospermopsin, within both the water column and mat material. In addition to known taxa, several novel taxa are currently being described including novel species of Nunduva and Rivularia, as well as novel genera. Results from this study indicate a need to further assess the spatial and temporal aspects of these blooms, in addition to their community structure, influencing factors and the production of toxic and bioactive compounds.
11:30 AM
New vectors of TTX analogues in the North Atlantic Coast: the crabs Afruca tangeri and Carciunus maenas (4740)
Primary Presenter: Sandra Lage, Algarve Centre of Marine Sciences (CCMAR-Algarve) (smlage@ualg.pt)
Tetrodotoxin (TTX) and its analogues are naturally occurring toxins typically linked to pufferfish consumption, and, to a lesser extent to marine gastropods and crabs, and are historically responsible for human poisoning cases and fatalities in Eastern Asia. To date, TTX and its analogues have been found in several other edible taxa, including, in the last decade, marine organisms from temperate European waters. Despite no monitoring or regulation of TTX in Europe, only one case of human intoxication has been reported, after the consumption of a marine gastropod. In this study, we report for the first time, the detection of TTX analogues, but no TTX, in two species of edible crabs Afruca tangeri (Eydoux, 1835) and Carcinus maenas (Linnaeus 1758) harvested in Europe, more precisely the Algarve (south of Portugal). In A. tangeri, three TTX analogues (TTX epimer, deoxyTTX, and trideoxyTTX) were found, but only trideoxyTTX was found in C. maenas. Thus, the accumulation of TTX analogues might be influenced by the crabs' different feeding ecology. The results provided here are notable because they give the European Food Safety Authority (EFSA) new information on the current incidence of emergent marine toxins in Europe, and highlight the need to monitor TTX and analogues in edible species identified as TTX-bearers to provide adequate health protection.
CS018 Harmful blooms
Description
Time: 10:30 AM
Date: 8/6/2023
Room: Sala Palma