Biology subjects

Hollister, J. W.

Publications and source records attributed to Hollister, J. W..

3 recordsLinked to original sources

bioRxiv2026

Evaluating satellite and modeled lake surface water temperature across the contiguous United States.

We developed a model to predict surface water temperature across U.S. lakes using satellite remote sensing and in situ observations to enhance cyanobacterial harmful algal bloom (cyanoHAB) forecasting. The study focused on Sentinel-3 Ocean and Land Colour Instrument (OLCI) sensor resolved lakes. We developed random forest models using both Landsat-derived and in-situ-measured surface water temperature. Landsat models offered broad spatial and temporal coverage of all OLCI resolved lakes, but they were sensitive to cloud cover and required filtering to minimize error. In contrast, the in situ model represented fewer OLCI resolved lakes, but yielded lower mean absolute error and bias. The models predicted lake surface temperature across the entire calendar year, with best performance (RMSEapplied=1.11; biasapplied=0.01; MAEapplied=0.77) from the in situ model. This approach allowed for the continuous prediction of lake surface temperatures from 1.1 to 31.6 {degrees}C for unfrozen, open-water conditions critical for improving the accuracy of cyanoHAB forecasting. A key strength of this study was the use of an extensive dataset and model validation against in situ observations, which improved predictive accuracy throughout the year across all seasons. The predictive model offers a water resource tool for management, ecosystem protection, and public health.

ecology↗

bioRxiv2025

Comparing fluorometric methods (in vivo vs extracted) for cyanoHAB monitoring in six Rhode Island ponds

Harmful algal blooms caused by cyanobacteria (cyanoHABs) are detrimental to human and environmental health and can be difficult to monitor without specialized training and equipment. A variety of instruments have been developed to measure cyanoHAB indicators (i.e., chlorophyll a or phycocyanin) that do not require advanced laboratory processes (e.g., pigment extraction). We compared measurements from five in vivo fluorometers (Turner Trilogy in-vivo module, Turner Fluorosense, Turner Cyanofluor, bbe AlgaeTorch, and bbe Phycoprobe) to results from solvent-based extractions for chlorophyll a and phycocyanin at six different waterbodies in Rhode Island. We found a strong relationship between extracted phycocyanin and in vivo fluorometers (R2 ranging from 0.78-0.96). We found less consistency between in vivo measurements of chlorophyll a and the extracted results (R2 between 0.34 and 0.82). Some variability in the chlorophyll a results can be explained by differences in the phytoplankton community across the different sampling sites. Phycocyanin results from in vivo fluorometry were also strongly related with cell counts, which implies that phycocyanin measurements from these instruments can be a good proxy for cell counts. Many federal, state, and local entities use cell counts of cyanobacteria to determine when to issue health or contact advisories for waterbodies. Producing accurate cell counts requires highly specialized training/equipment, processing time, and counts can vary greatly between technicians. The results from this study encourage further adoption of in vivo fluorometry and phycocyanin for cyanoHAB monitoring efforts.

ecology↗

bioRxiv2020

Increasing Chlorophyll a Amid Stable Nutrient Concentrations in Rhode Island Lakes and Reservoirs

Addressing anthropogenic impacts on aquatic ecosystems is a focus of lake management. Controlling phosphorus and nitrogen can mitigate these impacts, but determining management effectiveness requires long-term datasets. Recent analysis of the LAke multi-scaled GeOSpatial and temporal database for the Northeast (LAGOSNE) United States found stable water quality in the northeastern and midwestern United States, however, sub-regional trends may be obscured. We analyze a sub-regional (i.e., 3000 km2) trend with the University of Rhode Islands Watershed Watch Volunteer Monitoring Program (URIWW) dataset. URIWW has collected water quality data on Rhode Island lakes and reservoirs for over 25 years. The LAGOSNE and URIWW datasets allow for comparison of water quality trends at regional and sub-regional extents, respectively. We assess regional (LAGOSNE) and state (URIWW) trends with yearly mean anomalies calculated on a per-station basis. Sub-regionally, temperature and chlorophyll a increased from 1993 to 2016. Total nitrogen shows a weak increase driven by low years in the early 1990s. Total phosphorus and the nitrogen:phosphorus ratio (N:P) were stable. At the regional scale, the LAGOSNE dataset shows similar trends to prior studies of the LAGOSNE with chlorophyll a, total nitrogen, total phosphorus, and N:P all stable over time. In short, algal biomass, as measured by chlorophyll a in Rhode Island lakes and reservoirs is increasing, despite stability in total nitrogen, total phosphorus, and the nitrogen to phosphorus ratio. This analysis suggests an association between lake temperature and primary production. Additionally, we demonstrate both the value of long-term monitoring programs, like URIWW, for identifying trends in environmental condition, and the utility of site-specific anomalies for analyzing for long-term water quality trends.

ecology↗