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At least 721 records · Page 40Linked to original sources

USGS1989

Aquifer tests in the flood-plain alluvium and Santa Fe group at the Rio Grande near Canutillo, El Paso County, Texas

An aquifer system consisting of the Rio Grande flood-plain alluvium and Santa Fe Group underlying the southern Mesilla Valley in Dona Ana County, New Mexico and El Paso County, Texas has become an important source of water for both municipal and agricultural uses. Determination of aquifer properties is essential in order to evaluate groundwater potential for increasing water demand and potential streamflow depletion of the Rio Grande due to groundwater development. The aquifer system at the Canutillo well field hydrologic section was divided into a shallow, intermediate, and deep zone based on geohydrologic characteristics. Aquifer properties of specific zones at the test site were determined from a series of multiple-well aquifer tests conducted from December 3, 1985 through January 20, 1986. The Rio Grande is hydraulically connected to the shallow flood-plain alluvium. Water generally occurs within the shallow zone under unconfined conditions, within the intermediate zone under semiconfined conditions, and within the deep zone under confined conditions. (USGS)

Water-Resources Investigations Report↗

USGS1991

Field experiments and simulations of infiltration-rate response to changes in hydrologic conditions for an artificial-recharge test basin near Oakes, southeastern North Dakota

Ponded depth in an artificial-recharge basin was used as a management option to conduct turbid water from the James River to the Oakes aquifer. Infiltration-rate response to changes in ponded depth was evaluated for a 15xl5-meter artificial-recharge test basin constructed in a medium-sandy soil in the irrigation area near Oakes, southeastern North Dakota. Field experiments conducted at the test basin indicated that the clogged soil surface was easily scoured by currents caused by the addition of turbid water to increase ponded depth. Field measurements and computer-model simulations indicated that infiltration-rate response to an increase in ponded depth would be large for a clogged soil condition consisting of a surface filter-cake layer 0.1 centimeter in depth underlain by a sediment-clogged layer extending from 0.1 to 23 centimeters beneath the basin floor. Simulated infiltration-rate response to changes in ponded depth for surface filter-cake layer impedance values ranging from 0 to 1,000 hours indicated that infiltration-rate response would approach and remain near the maximum value for impedance values greater than 10 hours. The smallest infiltration-rate response would occur for impedance values less than 1 hour. For the case of a ground-water mound intersecting the basin floor, the percentage of infiltration-rate response to changes in ponded depth was not influenced by basin geometry, basin surface area, or underlying aquifer hydraulic conductivity. The simulated infiltration-rate response to changes in ponded depth increased when the water-table depth was shallow. Total recharge per unit area was greater for artificial-recharge basins having a less compact geometry than for artificial-recharge basins having a more compact geometry, for artificial-recharge basins having a small surface area than for artificial-recharge basins having a large surface area, and for artificial-recharge basins where underlying aquifer hydraulic conductivity was large rather than small. Artificial-recharge basin conditions most conducive to an effective infiltration-rate response to changes in ponded depth were least conducive to an enhanced total recharge.

Water-Resources Investigations Report↗

USGS2010

An empirical test of the 'shark nursery area concept' in Texas bays using a long-term fisheries-independent data set

Using a long-term fisheries-independent data set, we tested the 'shark nursery area concept' proposed by Heupel et al. (2007) with the suggested working assumptions that a shark nursery habitat would: (1) have an abundance of immature sharks greater than the mean abundance across all habitats where they occur; (2) be used by sharks repeatedly through time (years); and (3) see immature sharks remaining within the habitat for extended periods of time. We tested this concept using young-of-the-year (age 0) and juvenile (age 1+ yr) bull sharks Carcharhinus leucas from gill-net surveys conducted in Texas bays from 1976 to 2006 to estimate the potential nursery function of 9 coastal bays. Of the 9 bay systems considered as potential nursery habitat, only Matagorda Bay satisfied all 3 criteria for young-of-the-year bull sharks. Both Matagorda and San Antonio Bays met the criteria for juvenile bull sharks. Through these analyses we examined the utility of this approach for characterizing nursery areas and we also describe some practical considerations, such as the influence of the temporal or spatial scales considered when applying the nursery role concept to shark populations.

Texas↗

USGS2018

Sediment transport model including short-lived radioisotopes: Model description and idealized test cases

Geochronologies derived from sediment cores in coastal locations are often used to infer event bed characteristics such as deposit thicknesses and accumulation rates. Such studies commonly use naturally occurring, short-lived radioisotopes, such as Beryllium-7 ( 7 Be) and Thorium-234 ( 234 Th), to study depositional and post-depositional processes. These radioisotope activities, however, are not generally represented in sediment transport models that characterize coastal flood and storm deposition with grain size patterns and deposit thicknesses. We modified the Community Sediment Transport Modeling System (CSTMS) to account for reactive tracers and used this capability to represent the behavior of these short-lived radioisotopes on the sediment bed. This paper describes the model and presents results from a set of idealized, one-dimensional (vertical) test cases. The model configuration represented fluvial deposition followed by periods of episodic storm resuspension. Sensitivity tests explored the influence on seabed radioisotope profiles by the intensities of bioturbation and wave resuspension and the thickness of fluvial deposits. The intensity of biodiffusion affected the persistence of fluvial event beds as evidenced by 7 Be. Both resuspension and biodiffusion increased the modeled seabed inventory of 234 Th. A thick fluvial deposit increased the seabed inventory of 7 Be and 234 Th but mixing over time greatly reduced the difference in inventory of 234 Th in fluvial deposits of different thicknesses.

Journal of Marine Science and Engineering↗

USGS2020

Tests in a semi-natural environment suggest that bait and switch strategy could be used to control invasive Common Carp

Common Carp ( Cyprinus carpio Linnaeus, 1758), is a highly invasive species that has had profound effects on biodiversity and ecosystem services. Many Carp management methods have been applied including physical removal, pesticide treatments of whole lakes, and water drawdowns. Herein, we tested key elements of a potential “bait and switch” approach in which corn could be used to induce feeding aggregations of Carp and then switched for corn pellets with a pesticide Antimycin-A (ANT-A) to selectively target the Carp. First, laboratory experiments were used to determine if addition of lethal concentrations of ANT-A to corn pellets deterred Carp from eating corn-based food pellets. Second, a pond experiment tested if a corn-based bait containing ANT-A functioned as a species-specific Carp management tool in a semi-natural environment with three common native fishes: White Sucker ( Catostomus commersonii Lacepède, 1803), Yellow Perch ( Perca flavescens Mitchill, 1814), and Bluegill ( Lepomis macrochirus Rafinesque, 1819). The use of baited sites by Carp and native species was monitored using passive integrated transponder (PIT) tags. Mortality of each species and presence of corn in their digestive tracts was also monitored. Our laboratory experiment showed that presence of ANT-A did not deter Carp from consuming the pellets. The pond experiment showed that only Carp perished in significant numbers once toxic bait was applied. Further, only Carp increased their use of baited sites once baiting began, and only Carp had corn in their digestive tracts. Overall, our results indicate that corn might function as a species-specific Carp attractant in systems of North American Midwest and that corn-based bait can be used to effectively conceal a lethal dose of ANT-A. Further research is necessary to refine this potential management tool, specifically investigating the behavioral and social dynamics of Carp aggregating at sites baited with corn to enhance the temporal and spatial specificity of pesticide application.z

Management of Biological Invasions↗

USGS1981

Evaluation of coproexamination as a diagnostic test for avian botulism

Fecal extracts and blood sera from 113 ducks showing clinical signs of botulism were examined for Clostridium botulinum type C toxin by means of the mouse toxicity test to evaluate coproexamination as a diagnostic procedure, as compared with demonstration of toxin in serum. When death of test mice unprotected with type specific antitoxin (while protected controls survived) was the criterion, 78.8% of the sera and 5.3% of the fecal extracts were positive. When characteristic signs of intoxication in the unprotected mice was included as evidence of toxin in the specimens, these percentages increased to 86.7 and 6.2, respectively. Fecal specimens were collected hourly for the first 6 h after peroral dosing of eight mallards ( Anas platyrhynchos ) with 1.0 LD 50 , of type C toxin and at 24, 48, and 72 h from birds surviving that long. From 2 to 4 toxin-positive specimens were passed by all eight ducks during the first 6 h, five specimens were positive at 24 h, and three were positive at 48 h. Only three specimens were collected at 72 h, all of which were negative. These findings suggest that attempts to detect toxin in the feces of wild ducks might have been more successful had the birds been captured earlier in the course of the disease.

Utah↗

USGS2015

Total protein concentration and diagnostic test results for gray wolf ( Canis lupus ) serum using Nobuto filter paper strips

Nobuto filter paper strips are widely used for storing blood-serum samples, but the recovery of proteins from these strips following rehydration is unknown. Poor recovery of proteins could reduce the concentration of antibodies and antigens and reduce the sensitivity of diagnostic assays. We compared the protein concentration, and its association with test sensitivity, of eluted Nobuto strip samples with paired sera. We collected and froze serum from five gray wolves ( Canis lupus ) for 8 mo. When thawed, we used a spectrophotometer (absorbance 280 nm) to determine the serum protein concentration for paired sera and Nobuto eluates for each animal in 2-fold serial dilutions. Total protein concentration was similar for both sample storage methods (Nobuto eluates and control sera), except for the undiluted samples in which Nobuto eluates had higher total protein concentrations. Both sample storage methods appear to produce similar results using the SNAP® 4Dx® Test to detect antibodies against pathogens causing Lyme disease, anaplasmosis, and ehrlichiosis as well as antigen for canine heartworm disease.

Journal of Wildlife Diseases↗

USGS2004

Combined impacts of Black-crowned Night-Heron predation/disturbance and various management activities on Roseate Tern productivity in 2003, and testing of a video surveillance system for recording the diurnal and nocturnal behavior of terns and night-herons at Falkner Island, Stewart B. McKinney National Wildlife Refuge, Connecticut, in 2004: Report to U.S. Fish and Wildlife Service, Stewart B. McKinney National Wildlife Refuge, Westbrook, Connecticut and U.S. Fish and Wildlife Service, Region 5 Regional Office, Hadley, Massachusetts

Falkner Island (FICT), a unit of the U.S. Fish and Wildlife Service's Stewart B. McKinney National Wildlife Refuge (SBMNWR) since 1985, is located in Long Island Sound 5 km south of Guilford, CT. For more than three decades it has been the site of the only large breeding colony in Connecticut of the federally endangered Northwest Atlantic population of Roseate Terns (Sterna dougallii) and the state's largest colony of Common Terns (S. hirundo). Both species have been studied at this site since 1978 as part of the Falkner Island Tern Project (FITP), and since 1987 also as part of a regional Cooperative Roseate Tern Metapopulation Dynamics and Ecology Project (CRTMP), both coordinated by Dr. Jeffrey A. Spendelow of the U.S. Geological Survey's Patuxent Wildlife Research Center (USGS-PWRC). From 1997-2002 the Roseate Tern breeding population at this site declined by more than 50% from about 150 to about 70 nesting pairs, mostly as a result of the nocturnal predation and disturbance of tern chicks and eggs by Black-crowned Night-Herons (Nycticorax nycticorax). Here we report the results of research done with the goal of improving management of nocturnal predators and developing new practices/structures to reduce losses of tern eggs and chicks so as to prevent the abandonment of this site by Roseate Terns. Notification of release of the USGS 'Quick Response Funds' (QRF) that were to be used to support the part of this study entitled 'Nocturnal behavior/interactions of endangered Roseate Terns and Black-crowned Night-Herons', and final approval of the Study Plan for this research did not occur until after the breeding season in 2003 was well underway. As a result, some work will need to be completed during the 2004 field season. There are two major objectives of this study. The first is to collect basic information (a) on the nocturnal behavior and interactions of Roseate (and Common) Terns with predatory Black-crowned Night-Herons, and (b) on how the behavior of the night-herons and the behavior and productivity of the terns are affected by the activities of management personnel (or researchers) that may be moving around the island at night. The second objective is to develop new structures (or to modify existing ones) that can be used by adult Roseate Terns for nesting sites and/or by chicks as hiding sites so that tern eggs and chicks will be less susceptible to night-heron predation. Work on the development and comparative use of various man-made structures began prior to the start of the 2003 nesting season; work on the evaluation and testing of a video surveillance system to study the nocturnal behavior of the terns and night-herons began in June 2003. Reported here are (1) the results of work on the placement and use by Roseate Terns of several types of structures in different habitats, and (2) a description of the set-up, testing, and evaluation of a multi-camera video system to record tern and predator behavior during both day and night. Also given here is some additional information on other factors that affected the productivity of the Roseate Terns at FICT collected as part of the CRTMP which served as the underlying foundation for the additional work done with support of the 2003 Quick Response Funds.

Book↗

USGS2002

Test for age-specificity in survival of the common tern

Much effort in life-history theory has been addressed to the dependence of life-history traits on age, especially the phenomenon of senescence and its evolution. Although senescent declines in survival are well documented in humans and in domestic and laboratory animals, evidence for their occurrence and importance in wild animal species remains limited and equivocal. Several recent papers have suggested that methodological issues may contribute to this problem, and have encouraged investigators to improve sampling designs and to analyse their data using recently developed approaches to modelling of capture-mark-recapture data. Here we report on a three-year, two-site, mark-recapture study of known-aged common terns (Sterna hirundo) in the north-eastern USA. The study was nested within a long-term ecological study in which large numbers of chicks had been banded in each year for > 25 years. We used a range of models to test the hypothesis of an influence of age on survival probability. We also tested for a possible influence of sex on survival. The cross-sectional design of the study (one year's parameter estimates) avoided the possible confounding of effects of age and time. The study was conducted at a time when one of the study sites was being colonized and numbers were increasing rapidly. We detected two-way movements between the sites and estimated movement probabilities in the year for which they could be modelled. We also obtained limited data on emigration from our study area to more distant sites. We found no evidence that survival depended on either sex or age, except that survival was lower among the youngest birds (ages 2-3 years). Despite the large number of birds included in the study (1599 known-aged birds, 2367 total), confidence limits on estimates of survival probability were wide, especially for the oldest age-classes, so that a slight decline in survival late in life could not have been detected. In addition, the cross-sectional design of this study meant that a decline in survival probability within individuals (actuarial senescence) could have been masked by heterogeneity in survival probability among individuals (mortality selection). This emphasizes the need for the development of modelling tools permitting separation of these two phenomena, valid under field conditions in which the recapture probabilities are less than one.

Book chapter↗

USGS2000

The Japanese Quail as an avian model for testing endocrine disrupting chemicals: endocrine and behavioral end points

Birds have extremely varied reproductive strategies. As such, the impact of endocrine disrupting chemicals (EDCs) can greatly differ across avian species. Precocial species, such as Japanese quail appear to be most sensitive to EDC effects during embryonic development, particularly sexual differentiation. A great deal is known about the ontogeny of Japanese quail (Coturnix japonica) relative to endocrine, neuro-endocrine, and behavioral components of reproduction. Therefore, this species provides an excellent model for understanding effects of EDCs on reproductive biology with exposure at specific stages of the life cycle. The purpose of these experiments was to conduct a 1- or 2- generation experiment with positive or negative control chemicals and to determine changes in selected end points. Japanese quail embryos were exposed to estradiol benzoate (EB; positive control) in a 2-generation design or to fadrozole (FAD; negative control) in a 1-generation design. Embryonic EB treatment resulted in significant reductions (p< 0.5) in hen day production (90.2 vs 54.1; control vs EB, resp.) and fertility (85.3 vs 33.4%, control vs EB, resp.). Males showed sharply reduced courtship and mating behaviors as well as increased lag time (26 vs 148 sec; control vs EB) in behavioral tests. Fadrozole exposure resulted in reduced hatchability of fertile eggs, particularly at higher doses. There were no significant effects on courtship and mating behavior of males although males showed an increased lag time in their responses, nally, a behavioral test for studying motor and fear responses in young chicks was used; chicks exposed to an estrogenic pesticide (methoxychlor) showed some deficits. In summary, the use of appropriate and reliable end points that are responsive to endocrine disruption are critical for assessment of EDCs. Supported in part by EPA grant R826134.

Society of Environmental Toxicology and Chemistry,↗

USGS2010

Evaluating propagation method performance over time with Bayesian updating: An application to incubator testing

In captive-rearing programs, small sample sizes can limit the quality of information on performance of propagation methods. Bayesian updating can be used to increase information on method performance over time. We demonstrate an application to incubator testing at USGS Patuxent Wildlife Research Center. A new type of incubator was purchased for use in the whooping crane (Grus americana) propagation program, which produces birds for release. We tested the new incubator for reliability, using sandhill crane (Grus canadensis) eggs as surrogates. We determined that the new incubator should result in hatching rates no more than 5% lower than the available incubators, with 95% confidence, before it would be used to incubate whooping crane eggs. In 2007, 5 healthy chicks hatched from 12 eggs in the new incubator, and 2 hatched from 5 in an available incubator, for a median posterior difference of <1%, but with a large 95% credible interval (-41%, 43%). In 2008, we implemented a double-blind evaluation method, where a veterinarian determined whether eggs produced chicks that, at hatching, had no apparent health problems that would impede future release. We used the 2007 estimates as priors in the 2008 analysis. In 2008, 7 normal chicks hatched from 15 eggs in the new incubator, and 11 hatched from 15 in an available incubator, for a median posterior difference of 19%, with 95% credible interval (-8%, 44%). The increased sample size has increased our understanding of incubator performance. While additional data will be collected, at this time the new incubator does not appear adequate for use with whooping crane eggs.

Book chapter↗

USGS2005

In situ treatability testing of reductive dechlorination in wetland sediments

In situ treatability testing was conducted in the discharge wetlands along West Branch Canal Creek at Aberdeen Proving Ground, MD. The potential for stimulating reductive dechlorination of 1,1,2,2-tetrachloroethane, tetrachloroethylene, trichloroethylene, and carbon tetrachloride in areas of preferential discharge or seeps was evaluated. Geological Survey that degrades chlorinated ethanes and ethylenes was tested using MICRO-Trac??? devices. At seep 3-4W, results of the C and BA MICRO-Trac??? treatments showed essentially no biodegradation of chlorinated solvents occurring under natural and bioaugmented conditions. Results of geochemical samples at this site indicated predominantly iron- and sulfate-reducing conditions consistent with the rapid discharge rates previously measured. The biostimulated treatment showed stimulation of methanogenic conditions and partial degradation of the parent chlorinated VOC to intermediate chlorinated compounds. The bioaugmented and bistimulated treatment showed the highest production of methane, the highest removal of parent compounds and intermediate daughter products, and the highest production of the non-chlorinated end product ethylene. This is an abstract of a paper presented at the proceedings of the 8th International In Situ and On-Site Bioremediation Symposium (Baltimore, MD 6/6-9/2005).

Conference Paper↗

USGS2006

Niche evolution and adaptive radiation: Testing the order of trait divergence

In the course of an adaptive radiation, the evolution of niche parameters is of particular interest for understanding modes of speciation and the consequences for coexistence of related species within communities. We pose a general question: In the course of an evolutionary radiation, do traits related to within-community niche differences (?? niche) evolve before or after differentiation of macrohabitat affinity or climatic tolerances (?? niche)? Here we introduce a new test to address this question, based on a modification of the method of independent contrasts. The divergence order test (DOT) is based on the average age of the nodes on a tree, weighted by the absolute magnitude of the contrast at each node for a particular trait. The comparison of these weighted averages reveals whether large divergences for one trait have occurred earlier or later in the course of diversification, relative to a second trait; significance is determined by bootstrapping from maximum-likelihood ancestral state reconstructions. The method is applied to the evolution of Ceanothus, a woody plant group in California, in which co-occurring species exhibit significant differences in a key leaf trait (specific leaf area) associated with contrasting physiological and life history strategies. Co-occurring species differ more for this trait than expected under a null model of community assembly. This ?? niche difference evolved early in the divergence of two major subclades within Ceanothus, whereas climatic distributions (?? niche traits) diversified later within each of the subclades. However, rapid evolution of climate parameters makes inferences of early divergence events highly uncertain, and differentiation of the ?? niche might have taken place throughout the evolution of the group, without leaving a clear phylogenetic signal. Similar patterns observed in several plant and animal groups suggest that early divergence of ?? niche traits might be a common feature of niche evolution in many adaptive radiations. ?? 2006 by the Ecological Society of America.

Ecology↗

USGS2006

Analysis of single-hole and cross-hole tracer tests conducted at the Nye County early warning drilling program well complex, Nye County, Nevada

As part of the effort to understand the flow and transport characteristics downgradient from the proposed high-level radioactive waste geologic repository at Yucca Mountain, Nevada, single- and cross-hole tracer tests were conducted from December 2004 through October 2005 in boreholes at the Nye County 22 well complex. The results were analyzed for transport properties using both numerical and analytical solutions of the governing advection dispersion equation. Preliminary results indicate effective flow porosity values ranging from 1.0 ?? 10-2 for an individual flow path to 2.0 ?? 10 -1 for composite flow paths, longitudinal dispersivity ranging from 0.3 to 3 m, and a transverse horizontal dispersivity of 0.03 m. Individual flow paths identified from the cross-hole testing indicate some solute diffusion into the stagnant portion of the alluvial aquifer.

Conference Paper↗

USGS2007

Northeast Kansas well tests oil, gas possibilities in Precambrian rocks

Tests for oil and gas prospects in Precambrian rocks in Northeast Kansas is currently being undertaken by WTW Operating LLC. It drilled in late 2005 the no.1 Wilson well with a depth of 5,772ft, 1,826ft into the Precambrian basement on a venture testing the possibility of oil and gas in the crystalline rocks. The basin extends northeast into Nebraska and Iowa and is a shallow cratonic basin filled with Paleozoic segments. The rocks have been previously though as not a potential for oil and gas due to the rocks' crystalline and nonporous character with the exception of the Midcontinent rift system (MRS). Later, though, small quantities of oil have been produced on the Central Kansas uplift from granite wash while the wells also produced low-Btu with swabbing operations. The recovered gas contained considerable nonflammable components of nitrogen, carbon dioxide and helium which equates to a low btu content of 283.

Kansas↗

USGS2008

Use of an annular chamber for testing thermal preference of westslope cutthroat trout and rainbow trout

Remaining populations of westslope cutthroat trout (Oncorhynchus clarkii lewisi) in western North America are primarily confined to cold headwaters whereas nonnative rainbow trout (Oncorhynchus mykiss) predominate in warmer, lower elevation stream sections historically occupied by westslope cutthroat trout. We tested whether differing thermal preferences could account for the spatial segregation observed in the field. Thermal preferences of age-1 westslope cutthroat trout and rainbow trout (125 to 150 mm total length) were assessed in the laboratory using a modified annular preference chamber at acclimation temperatures of 10, 12, 14, and 16??C Final preferred temperature of westslope cutthroat trout (14.9??C) was similar to that of rainbow trout (14.8??C) when tested in a thermal gradient of 11-17??C The high degree of overlap in thermal preference indicates the two species have similar thermal niches and a high potential for competition. We suggest several modifications to the annular preference chamber to improve performance in future studies.

Journal of Freshwater Ecology↗

USGS2012

Timing and proximate causes of mortality in wild bird populations: testing Ashmole’s hypothesis

Fecundity in birds is widely recognized to increase with latitude across diverse phylogenetic groups and regions, yet the causes of this variation remain enigmatic. Ashmole’s hypothesis is one of the most broadly accepted explanations for this pattern. This hypothesis suggests that increasing seasonality leads to increasing overwinter mortality due to resource scarcity during the lean season (e.g., winter) in higher latitude climates. This mortality is then thought to yield increased per-capita resources for breeding that allow larger clutch sizes at high latitudes. Support for this hypothesis has been based on indirect tests, whereas the underlying mechanisms and assumptions remain poorly explored. We used a meta-analysis of over 150 published studies to test two underlying and critical assumptions of Ashmole’s hypothesis: first, that ad ult mortality is greatest during the season of greatest resource scarcity, and second, t hat most mortality is caused by starvation. We found that the lean season (winter) was generally not the season of greatest mortality. Instead, spring or summer was most frequently the season of greatest mortality. Moreover, monthly survival rates were not explained by monthly productivity, again opposing predictions from Ashmole’s hypothesis. Finally, predation, rather than starvation, was the most frequent proximate cause o f mortality. Our results do not support the mechanistic predictions of Ashmole‘s hypothesis, and suggest alternative explanations of latitudinal variation in clutch size should remain under consideration. Our meta-analysis also highlights a paucity of data available on the timing and causes of mortality in many bird populations, particularly tropical bird populations, despite the clear theoretical and empirical importance of such data.

Thesis↗

USGS2010

Do three massive coral species from the same reef record the same SST signal? A test from the Dry Tortugas, Florida Keys

Paleoclimatologists have reconstructed century-long records of sea surface temperature (SST) in the Pacific using the Sr/Ca of massive corals, whereas similar reconstructions in the Atlantic have not proceeded at the same pace. Past research in the Florida Keys has focused on Montastrea spp. , an abundant and fast-growing massive coral, thus a good candidate for climate reconstructions. However, coral records from the Florida Keys are complicated by freshwater flux, which varies the Sr/Ca in seawater, thus confounding the Sr/Ca to SST signal. In this research, we compared the monthly Sr/Ca variations in three massive corals species ( Montastraea faveolata, Diploria strigosa, and Siderastrea siderea ) from the same reef in the nearly pristine Dry Tortugas National Park (24.70N, 82.80W) at the southwestern extent of the Florida Keys. This location is ideal for a calibration study as hourly water temperature records are available and the remote reef is far from mainland freshwater influence. These corals experienced the same environmental conditions (water depth, clarity, Sr/Ca of seawater, etc.) but differ in the mean annual growth rates (0.86 ±0.10 (1σ) cm/year M. faveolata ; 0.67 ±0.04 (1σ) cm/year D. strigosa ; 0.44 ±0.04 (1σ) cm/year S. siderea ). The mean Sr/Ca values are not the same but decrease with mean annual growth rates (9.201 ±0.091 (1σ) mmol/mol M. faveolata ; 9.177 ±0.081 (1σ) mmol/mol D. strigosa ; 8.964 ±0.12 (1σ) mmol/mol S. siderea ), thus supporting the “vital effect” or biological differences during calcification between coral species. The amplitude of the seasonal cycle in Sr/Ca varies with the slower growing S. siderea having the largest mean amplitude and D. strigosa the smallest (0.340 mmol/mol S. siderea ; 0.284 mmol/mol M. faveolata ; 0.238 mmol/mol D. strigosa ). We confirmed our sampling methods by conducting several intracolony and intercolony coral Sr/Ca replication tests and found a high correlation in all tests (>0.95 S. siderea ; >0.90 D. strigosa ; >0.83 M. faveolata; p < 0.05). The weighted linear regression of monthly coral Sr/Ca to mean monthly SST revealed that S. siderea captured the seasonal and interannual variability in SST ( r = -0.97, -0.61 monthly and monthly anomalies, respectively, p < 0.05). The other corals have reduced correlation with monthly anomalies and do not capture the seasonal variability with the same fidelity as S. siderea . All three corals were sampled along the thecal wall following the same procedures; however, each coral species has a different skeletal structure, density, and micro-scale growth patterns. We hypothesize the thecal wall of S. siderea calcifies at a continuous rate along the time-growth axis whereas the wall of D. strigosa and M. faveolata reflects a more complex signal. Of the three species, the slow growing S. siderea provides a robust reconstruction of mean monthly SST for the Dry Tortugas thus suitable for longer centennial-scale reconstructions.

Florida↗