Seawater Temperature Data Research Articles

Global Inference and Test for Eigensystems of Imaging Data Over Complicated Domains

A nonparametric approach for analyzing eigensystems of image data over a complex domain is novelly developed. The proposed estimators, which are based on bivariate splines, have both oracle efficiency of O p ( n − 1 / 2 ) , meaning they are asymptotically indistinguishable from estimators computed with true trajectories, and computational efficiency with more convenient spectrum decomposition forms. Under mild conditions, we derive consistency and weak convergence of our proposed estimators, which can be used to construct confidence intervals and simultaneous confidence corridors for any individual eigenvalue and eigenfunction, as well as design uniform inference procedures for eigensystems with a diverging number of components. In addition, we extend our method to two-sample test problems. Extensive simulation results provide strong support for the asymptotic theory, and the procedures are applied to two potential seawater temperature data sets to demonstrate its validity.

Were Late Jurassic climatic fluctuations responses to Pangea breakup? Evidence from isotopic analyses of belemnite rostra from the eastern Tethyan Ocean

Late Jurassic paleogeographic patterns were influenced by the growth of the Pacific plate and the breakup of Pangea, impacting the global paleoclimate during this warm and equable greenhouse period. However, the use of different proxies may introduce bias in seawater temperature reconstructions. In this study, we reconstructed midlatitude Tethyan seawater paleotemperatures in the Northern Hemisphere using carbonate clumped isotopes (Δ47) in well-preserved parts of belemnite rostra from the Upper Jurassic Hongqilafu Formation in the Taxkorgan Basin, southwest Xinjiang, China. Throughout the entire studied section, an increase in the 87Sr/86Sr ratio was observed. Comparison of this ratio with the published global seawater 87Sr/86Sr curve suggests a good correlation with the biostratigraphic and U-Pb age assignments of the Oxfordian−Tithonian interval. The Δ47-derived paleotemperature estimates indicate a long-term, relatively stable, and warm seawater temperature of ∼27 °C within the epipelagic zone of the eastern Tethyan Ocean during the Late Jurassic. Cooler seawater temperatures were recorded at the Oxfordian−Kimmeridgian boundary and in the late Tithonian, likely reflecting changes in paleogeography and paleoceanography resulting from the breakup of Pangea and/or variations in belemnite habitat depth. When compared with global seawater temperature data from different proxies, the results suggest that elevated atmospheric pCO2 levels during the Late Jurassic may have caused warmer conditions in midlatitude and polar regions. The reconstructed δ18Osea values exhibit a remarkably modern midlatitude seawater character and are more positive than values traditionally assumed for the Jurassic ice-free world. Given that the Taxkorgan Basin was located in a semi-enclosed basin and was dominated by evaporation in the Late Jurassic, the reconstructed δ18Osea values may represent regional seawater signals. Consequently, they cannot be used to support the existence of ice sheets in both polar regions. Our results suggest that climatic changes in the Jurassic greenhouse world may have been overprinted by local factors, potentially masking broader climatic trends.

Machine Learning-Based Anomaly Detection on Seawater Temperature Data with Oversampling

Machine Learning-Based Anomaly Detection on Seawater Temperature Data with Oversampling

Expendable Conductivity–Temperature–Depth-Assisted Fast Underwater Sound Speed Estimation by Convolutional Neural Network with Reduced Fully Connected Layers

Obtaining accurate sound speed profiles (SSPs) in near-real-time is of great significance for ocean exploration, underwater communication and improving the performance of sonar systems. In response to the problem that traditional sound speed estimation methods cannot obtain real-time sound speed distribution or rely too much on sonar observation data, we propose an SSP estimation method based on a convolutional neural network with reduced fully connected layers (RFC-CNN) in this paper. This method utilizes neural networks to extract the complex nonlinear features of various types of data. With the help of the historical SSPs and shallow seawater sound speed and temperature data obtained by expendable conductivity–temperature–depth probes (XCTDs), a more accurate estimation of the regional sound speed distribution can be realized quickly. This approach can save the observation cost and significantly improve the real-time performance of SSP estimation.

Elevated Seawater Temperature and Infection with Neoparamoeba perurans Exacerbate Complex Gill Disease in Farmed Atlantic Salmon (Salmo salar) in British Columbia, Canada.

Gill disorders and diseases are emergent health concerns affecting marine-farmed salmon, for which the causal factors are poorly understood in British Columbia (BC), Canada. This study sought to describe and compare spatial and temporal patterns of infection with Neoparamoeba perurans, the causal agent of amoebic gill disease, and visually assessed gill health scores in farmed Atlantic salmon. Gill tissue obtained during the Fisheries and Oceans Canada’s Fish Health Audit and Intelligence Program (DFO-FHAIP) between 2016 and 2020 were screened for N. perurans by qPCR. Semi-quantitative visual gill health assessments were conducted during the audits, and farms were assigned clinical AGD status based on microscopic visualization of N. perurans together with histopathological lesions. Seawater temperature and salinity data were collected from all active farms in the region during the study period. Trends in gill scores and associations with N. perurans infections were described and tested using an ordinal logistic mixed model. The amoeba was detected in 21% of 345 audited farms and in 12% of 1925 fish samples. Most (56%, n = 1898) samples had no visible gill damage (score = 0), and 23% had scores ≥ 2 (high). Distinct patterns of spatial and temporal variability in the rates of high gill scores and N. perurans infections are demonstrated. The model supported the statistically significant relationship observed between seawater temperature and the proportion of samples with elevated gill scores. The model also revealed a direct relationship between salinity and gill score but only in the presence of N. perurans. While the data suggest that histopathological lesions contributed to the gill scores, temperature and, to a lesser extent, salinity were significant risk factors of increased gill score. The results are discussed in the context of recently frequent thermal anomalies in the northeastern Pacific Ocean.

Is bigger always better? Designing economically feasible ocean thermal energy conversion systems using spatiotemporal resource data

Ocean Thermal Energy Conversion (OTEC) produces electricity using the temperature difference between warm surface and cold deep-sea water. OTEC systems in literature only limitedly consider seasonal seawater temperature variations and thus might not be adequately sized for off-design conditions. This potentially leads to techno-economically sub-optimal design choices. This paper sheds light on which design approach yields the most economically feasible OTEC system considering off-design conditions with 19 years of seawater temperature data in 3-h time steps. We find that systems sized for worst-case thermal resources yield the highest and steadiest electricity production. If seawater temperature variations are moderate, these systems also perform best economically in terms of Levelized Cost of Electricity (LCOE). We demonstrate our model for a 136 MWgross plant in Ende, Indonesia, with an LCOE of 15.12 US¢(2021)/kWh against a local electricity tariff of 15.77 US¢(2021)/kWh. The model is validated for different cost assumptions, system sizes, and temperature profiles to be useful globally. We give recommendations to curb costs and to move large-scale OTEC closer to today’s state of the art, e.g. by using multiple smaller seawater pipes instead of few large pipes. The model is useful to prove OTEC’s global economic feasibility and to promote the technology’s commercialisation.

Epidemiologic Characteristics and Case Fatality Rate of Vibrio vulnificus Infection: Analysis of 761 Cases From 2003 to 2016 in Korea.

Background Vibrio vulnificus infection is a highly fatal disease resulting from the consumption of raw or undercooked seafood and exposure to seawater containing the organism. It has been a nationally notifiable disease since 2000 in Korea. The aims of this study were to assess the trends in the incidence of V. vulnificus infection and its case fatality rate and to determine the epidemiologic characteristics to effectively prevent infection and lower mortality.MethodsWe analyzed the incidence trends of V. vulnificus infection by year, month, and region in 913 cases reported to the Korea Centers for Disease Control and Prevention (KCDC, currently Korea Disease Control and Prevention Agency) by the National Infectious Disease Surveillance System from 2001 to 2016. We analyzed the number of patients with V. vulnificus infection who were under the National Health Insurance Service (NHIS) and whose coastal seawater temperature data were provided by the Korea Oceanographic Data Center of the National Institute of Fisheries Science. Epidemiological investigations were followed up and analyzed for 761 patients from 2003 to 2016. A total of 152 patients who were not followed up were excluded from the analysis. The case fatality rate was analyzed for 325 cases reported to the KCDC from 2011 to 2016.ResultsThe mean incidence of V. vulnificus infection was 0.12 per 100,000 people, and the highest incidence was reported in September (41.1%) during the study period. The incidence rate per 100,000 people was the highest in Jeonnam (8.23). The number of patients who claimed to the NHIS was the highest in September (105 patients). The average seawater temperature was the highest at 24.1°C in August, and the average seawater temperature from August to October, when many cases occurred, was 22.4°C. The male-to-female ratio was 6:1, and 96.4% of the patients were aged ≥ 40 years. Of the patients, 96.1% had underlying diseases, the most common of which was liver cirrhosis (56.3%). The case fatality rate was 48.9%.ConclusionThe occurrence of V. vulnificus infection showed distinct seasonality, with a large number of cases occurring in the months when the seawater temperature was high; there were also distinct geographical characteristics. The incidence of V. vulnificus infection and mortality rates have not decreased for decades, and it is still an important public health problem with a high fatality rate.

Thalia longicauda(Quoy and Gaimard) from the south-western Atlantic Ocean (31°S–38°S): distribution and population structure

AbstractAlthough the salp Thalia longicauda is common in the southern hemisphere, there is little information on its biology and ecology. Our study aimed to describe the morphology of the development of solitaries and aggregates and to determine the developmental stages, length distribution and population structure of this species. Plankton samples were collected by the R/V ARA “Puerto Deseado” from 31°55′S to 38°08′S (October 2013). Thalia longicauda was present at 50% of the stations, ranging between 1.21 and 2970 ind. 1000 m−3. Solitaries and aggregates represented 53.76 and 46.24%, respectively. We described the growth of the blastogenic stolon and the formation of blocks of aggregates buds. Each solitary may produce at least three blocks with a total of 36–86 aggregate buds. The relationship between total number of aggregate buds (y) and total length of the solitary (x) was y = 3.321x − 13.489. We characterized six developmental stages for solitaries and four for aggregates. The juvenile/mature ratio of solitaries and aggregates suggested that the population was actively reproducing both sexually and asexually. Based on seawater temperature and salinity data, T. longicauda may be considered as a temperate species inhabiting the southern range of subtropical waters and the northern range of sub-Antarctic waters.

Descriptive Capability of Datasets as Proxy of Sea Water Temperature in Coastal Systems: An Evaluation from the Aegean Sea

Scientific and technological progresses have introduced diverse data sources for seawater temperature over broad temporal and spatial ranges. Here, we investigated the performance of satellite and model-based seawater temperature data for different temporal composites and depths. We applied an in-situ temperature time-series obtained in a coastal bottom in the Aegean Sea over three years, as the reference. Both datasets showed largely significant relationships based on cross-correlation analyses and presented descriptive properties of the in-situ conditions at corresponding depths. Based on the results of analyses, the modeling datasets presented more reliable results and representations of in-situ conditions than the datasets obtained from satellite for the coastal region. However, the datasets obtained from the satellite also provided reliable data for all time frames investigated, particularly in the mixed surface layer. Monthly datasets were more effective in providing descriptive values in long term studies. This is the first detailed study to explore the descriptive capacities of modeling for water temperature in coastal environments. According to the results, the selection of a dataset as a proxy for seawater temperature requires careful consideration. The present study provides an extensive baseline for evaluating the suitability of the application of specific datasets as proxies in coastal ecosystems.

Venerid bivalve Venus verrucosa as a high-resolution archive of seawater temperature in the Mediterranean Sea

High-resolution stable isotope data (δ18O, δ13C) were used to study growth strategies of the bivalve Venus verrucosa collected from three sites of the eastern coast of the Adriatic Sea. The principal objectives of this study were to identify the main growing season and to evaluate the potential applicability of δ18Oshell values to reconstruct the seasonal temperature variability. Calcium carbonate for oxygen and carbon isotope analyses was obtained by drilling the outer shell layer. Temporal and spatial variations in temperature and salinity values at the study sites were simulated using the 3D numerical ocean model ROMS. Annual periodicity of growth patterns was confirmed by δ18Oshell cycles which corresponded to the number of observed seasonal growth marks. Temporal alignment of stable oxygen data with modelled seawater temperature data indicates that V. verrucosa deposits shell material from March/April to December. Shell growth slowdown and/or cessation occurred between late winter and early spring when the seawater temperature dropped below 12 °C at the two northern sites, Istria and Pag Bay, and below 13 °C at the southern site, Kaštela Bay. Summer temperatures reconstructed from V. verrucosa agreed well with modelled summer temperatures, but lowest reconstructed temperatures were consistently higher than the modelled winter values. The range of δ18Oshell values obtained from V. verrucosa shells is higher than the range obtained previously from other species in the eastern Adriatic Sea, indicating the high potential of V. verrucosa for temperature reconstructions.

Seawater Temperature Outlier Detection Strategy Based on Wavelet Analysis for Solving the Migration Problem of Fishery Companies

As the global ocean temperature rises, many marine organisms begin to find new habitats. The problem of fish migration has a profound impact on the development of fisheries. This paper uses wavelet anomaly analysis method to find the abnormal value of seawater temperature, uses discrete wavelet decomposition and reconstruction to de-noise the time series, and predicts the age of the fishing company. Firstly, we conducted continuous wavelet analysis of seawater temperature data to obtain the relationship between seawater temperature change rate and time. We performed Fourier transform to obtain its transform function, and then reconstructed the sequence to obtain wavelet coefficients of seawater temperature transformation speed. After that, we used wavelet coefficients to conduct simulation screening to obtain all outliers. In this way, the time for bankruptcy under the best and worst conditions of the fishing company can be obtained. Although the model comprehensively considers many factors, in order to establish a universal model, idealizing many influencing factors has certain limitations. The predicted bankruptcy time may have a certain error from the actual.

Biomarker-based Seawater Temperatures of Winter Sinking Particles and Core-top Sediment in the Ulleung Basin of the East Sea

This study evaluates the application of biomarkerbased temperature proxy data (alkenone with its resultant $$U_{37}^{K'}$$ index and glycerol dialkyl glycerol tetraether (GDGT) with its resultant TEX86and TEX index) in the Ulleung Basin of the East Sea. Based $$U_{37}^{K'}$$ on the and TEX86 indices from particles trapped for 10 days in December, 2015 and core-top sediment as well as the comparison of these indices to in situ seawater temperature data (from 2012 to 2016) from the Korea Oceanographic Data Center, this study confirms that the $$U_{37}^{K'}$$ index of core-top sediment indicates the annual mean SST of the surface water. This study also suggests that TEX86 data of core-top sediment may represent the annual mean temperature of the subsurface water. However, a reliable calibration equation for GDGT will be required in this regional environment for the proper application of GDGT-based paleotemperature reconstruction.

A study of response of thermocline in the South China Sea to ENSO events

This paper investigates the response of the thermocline depth (TD) in the South China Sea (SCS) to the El Nino-Southern Oscillation (ENSO) events using 51-year (from 1960 to 2010) monthly seawater temperature and surface wind stress data acquired from the Simple Ocean Data Assimilation (SODA), together with heat flux data from the National Centers for Environmental Prediction (NCEP), precipitation data from the National Oceanic and Atmospheric Administration (NOAA) and evaporation data from the Woods Hole Oceanographic Institution (WHOI). It is indicated that the response of the SCS TD to the El Nino or La Nina events is in opposite phase. On one hand, the spatial-averaged TDs in the SCS (deeper than 200 m) appear as negative and positive anomalies during the mature phase of the El Nino and La Nina events, respectively. On the other hand, from June of the El Nino year to the subsequent April, the spatial patterns of TD in the north and south of 12°N appear as negative and positive anomalies, respectively, but present positive and negative anomalies for the La Nina case. However, positive and negative TD anomalies occur almost in the entire SCS in May of the subsequent year of the El Nino and La Nina events, respectively. It is suggested that the response of the TD in the SCS to the ENSO events is mainly caused by the sea surface buoyancy flux and the wind stress curl.

Over 10 million seawater temperature records for the United Kingdom Continental Shelf between 1880 and 2014 from 17 Cefas (United Kingdom government) marine data systems

Abstract. The datasets described here bring together quality-controlled seawater temperature measurements from over 130 years of departmental government-funded marine science investigations in the UK (United Kingdom). Since before the foundation of a Marine Biological Association fisheries laboratory in 1902 and through subsequent evolutions as the Directorate of Fisheries Research and the current Centre for Environment Fisheries & Aquaculture Science, UK government marine scientists and observers have been collecting seawater temperature data as part of oceanographic, chemical, biological, radiological, and other policy-driven research and observation programmes in UK waters. These datasets start with a few tens of records per year, rise to hundreds from the early 1900s, thousands by 1959, and hundreds of thousands by the 1980s, peaking with > 1 million for some years from 2000 onwards. The data source systems vary from time series at coastal monitoring stations or offshore platforms (buoys), through repeated research cruises or opportunistic sampling from ferry routes, to temperature extracts from CTD (conductivity, temperature, depth) profiles, oceanographic, fishery and plankton tows, and data collected from recreational scuba divers or electronic devices attached to marine animals. The datasets described have not been included in previous seawater temperature collation exercises (e.g. International Comprehensive Ocean–Atmosphere Data Set, Met Office Hadley Centre sea surface temperature data set, the centennial in situ observation-based estimates of sea surface temperatures), although some summary data reside in the British Oceanographic Data Centre (BODC) archive, the Marine Environment Monitoring and Assessment National (MERMAN) database and the International Council for the Exploration of the Sea (ICES) data centre. We envisage the data primarily providing a biologically and ecosystem-relevant context for regional assessments of changing hydrological conditions around the British Isles, although cross-matching with satellite-derived data for surface temperatures at specific times and in specific areas is another area in which the data could be of value (see e.g. Smit et al., 2013). Maps are provided indicating geographical coverage, which is generally within and around the UK Continental Shelf area, but occasionally extends north from Labrador and Greenland to east of Svalbard and southward to the Bay of Biscay. Example potential uses of the data are described using plots of data in four selected groups of four ICES rectangles covering areas of particular fisheries interest. The full dataset enables extensive data synthesis, for example in the southern North Sea where issues of spatial and numerical bias from a data source are explored. The full dataset also facilitates the construction of long-term temperature time series and an examination of changes in the phenology (seasonal timing) of ecosystem processes. This is done for a wide geographic area with an exploration of the limitations of data coverage over long periods. Throughout, we highlight and explore potential issues around the simple combination of data from the diverse and disparate sources collated here. The datasets are available on the Cefas Data Hub (https://www.cefas.co.uk/cefas-data-hub/). The referenced data sources are listed in Sect. 5.

Analysis of monthly variability of thermocline in the South China Sea

This study analyzes monthly variability of thermocline and its mechanism in the South China Sea (SCS). The study is based on 51-year (1960–2010) monthly seawater temperature and surface wind stress data from Simple Ocean Data Assimilation (SODA), together with heat flux, precipitation and evaporation data from the National Centers for Environmental Prediction (NCEP), the National Oceanic and Atmospheric Administration (NOAA) and the Woods Hole Oceanographic Institution, respectively. The results reveal that the upper boundary depth (Zup), lower boundary depth (Zlow), thickness (ΔZ) and intensity (T z ) of thermocline in the SCS show remarkable monthly variability. Being averaged for the deep basin of SCS, Zup deepens gradually from May to the following January and then shoals from February to May, while Zlow varies little throughout the whole year. Further diagnostics indicates that the monthly variability of Zup is mainly caused by the buoyancy flux and wind stress curl. Using a linear method, the impacts of the buoyancy flux and wind stress curl on Zup can be quantitatively distinguished. The results suggest that Zup tends to deepen about 4.6 m when the buoyancy flux increases by 1×10 -5 kg/(m∙s 3), while it shoals about 2.5 m when the wind stress curl strengthens by 1×10 -7 N/m³.

From Tropical to Sub-Tropical: Prolonged Reproductive Activity of the Invasive Ascidian Microcosmus exasperatus in the Eastern Mediterranean

The solitary ascidian Microcosmus exasperatus is globally distributed in tropical and sub-tropical waters. In the Mediterranean it is considered an invasive species introduced through the Suez Canal, with a restricted distribution in the eastern basin. In order to understand the potential of this species to establish sustainable communities at additional sites in the Mediterranean, we studied its reproduction cycle over a 2-year period in relation to seawater temperature and chlorophyll-a data. Although M. exasperatus reproduces seasonally, with significantly greater activity in summer and early fall, mature oocytes occur throughout the year, suggesting multiple spawning periods. We found that reproductive effort significantly correlated with seawater temperature, while chlorophyll-a showed a low and insignificant explanatory power. A combined regression model of both parameters yielded the highest explained variance, suggesting a synergic effect of these two factors. Such a prolonged reproductive activity period enables repeated recruitment events. In view of the anticipated rise in seawater temperature, we predict that this species will gradually expand its distribution further across the Mediterranean.

Annual shell growth pattern of the Stimpson's hard clam Mercenaria stimpsoni as revealed by sclerochronological and oxygen stable isotope measurements

Mercenaria stimpsoni (Stimpson's hard clam) is a shallow-water bivalve species distributed along mid- to high-latitude coasts of the Northwest Pacific influenced by the Oyashio cold current. As this animal can live for decades, oxygen isotopes of its shell can potentially provide long-term seawater temperature and salinity data. However, little is known about the life history traits of M. stimpsoni, which hampers their use in paleoclimatology. Thus, we investigated the growth patterns of three live-caught M. stimpsoni individuals from Funakoshi Bay, especially focusing on juvenile ontogenetic stages. Sclerochronological and high-resolution oxygen isotope analyses suggest that young (below age 10) specimens of this species grow predominantly between spring and fall, but ceased growing during the cold season when sea surface temperature drops below approximately 10°C. The results also show that ontogenetically older (>10yr) specimens grow shell material almost exclusively during summer. Oxygen isotopes in ontogenetically younger portions of the shells are a good indicator of past summer temperatures.

Timed Communication Buoy System: A Subsurface Mooring System for Efficient Sensor Data Recovery

Abstract An ocean subsurface mooring system is an effective platform for acquiring information that would advance our understanding of essential ocean processes and impacts of climate changes. Unlike a surface mooring system, data acquired from a subsurface mooring system cannot be downloaded until the whole system is retrieved. To achieve efficient sensor data recovery, a new, low-cost subsurface mooring system named the Timed Communication Buoy System (TCBS) was designed and implemented. The TCBS is usually integrated in the main float, and designated sensor data can be downloaded by the control system using a noncontact communication method termed Inductively Coupled Link. After data acquisition, an autonomous communication float in the TCBS can be released from the main float. Upon release, the communication float rises to the sea surface and transmits sensor data by satellite communication. To evaluate the performance of the TCBS, a short-term sea trial in the South China Sea (SCS) was conducted. Seawater temperature data over 30 days were collected and analyzed. The results demonstrated valid measurements of vertical wavenumber spectrum and frequency spectrum of internal waves in the SCS. TCBS will lead to important information needed to support fundamental research to better understand the characteristics of internal wave spectrum in the SCS.

Mass coral bleaching in the northern Persian Gulf, 2012

Coral bleaching events due to elevated temperatures are increasing in both frequency and magnitude worldwide. Mass bleaching was recorded at five sites in the northern Persian Gulf during August and September 2012. Based on available seawater temperature data from field, satellite and previous studies, we suggest that the coral bleaching threshold temperature in the northern Persian Gulf is between 33.5 and 34°C, which is about 1.5 to 2.5°C lower than that in the southern part. To assess the bleaching effects, coral genera counted during 60-minute dives were categorized into four groups including healthy, slightly bleached ( 50% bleached tissue) and fully bleached colonies. The anomalously high sea surface temperature resulted in massive coral bleaching (~84% coral colonies affected). Acropora spp. colonies, which are known as the most vulnerable corals to thermal stress, were less affected by the bleaching than massive corals, such as Porites , which are among the most thermo-tolerant corals. Turbid waters, suggested as coral refugia against global warming, did not protect corals in this study since most affected corals were found in the most turbid waters. The 2012 bleaching in the northern Persian Gulf was relatively strong from the viewpoint of coral bleaching severity. Long-term monitoring is needed to understand the actual consequences of the bleaching event on the coral reefs and communities.

Temperature-dependent photosynthesis in the intertidal alga Fucus gardneri and sensitivity to ongoing climate change

Understanding the photosynthetic responses of marine macroalgae to changes in their thermal environment is vital to characterizing the success of these habitat-forming primary producers in the face of climate change. We measured net photosynthesis in apical tips of Fucus gardneri collected from the intertidal zone of Friday Harbor, WA over a range of irradiance levels (0–1500μmolphotonsm−2s−1) at 10°, 14°, and 18°C to determine levels of saturating irradiance. We then recorded net photosynthesis at saturating irradiance in tips exposed to seawater temperatures ranging from 6 to 22°C, as well as dark respiration. Results show that F. gardneri at this location has a peak in net photosynthesis at 16–18°C seawater temperature, with significant declines in net photosynthesis at 20° and 22°C. Respiration showed a positive linear relationship with increasing seawater temperature. Using archived seawater temperature, irradiance, and tidal data, we produced a model of net photosynthesis over two years (October 2010–October 2012). Maximal seawater temperatures recorded at FHL rarely exceeded 14°C, suggesting that an increase of +2 and +4°C in seawater temperature would lead to increased net photosynthesis at this site. These results allowed us to develop a predictive model to forecast the net photosynthesis of F. gardneri at different intertidal elevations to explore the effects of seawater temperature and irradiance on net photosynthesis. We also examined the effects of the timing of high tide, testing the hypothesis that net photosynthesis will be highest at sites where submersion occurs during peak levels of irradiance. Our results suggest that as seawater temperatures increase (up to +4°C above ambient) F. gardneri below +1m MLLW tidal elevation will experience increases in net photosynthesis. These analyses also suggest that the effects of environmental change may depend in part on tidal regime, which determines the extent to which algae are submerged during times of day when irradiance is high.