Rocky intertidal temperature variability along the southeast coast of Australia: comparing data from in situ loggers, satellite-derived SST and terrestrial weather stations

Abstract

Predicting how both spatial and temporal variation in sea and air temperature influence the distribution of intertidal organisms is a pressing issue. We used data from satellites, weather stations and in situ loggers to test the hypothesis that satellite-derived sea surface temperatures (SSTs) and weather station air temperatures provide accurate estimates of ambient temperature variability on rocky intertidal shores for temporal (hourly for 1 yr) and spatial (10 m to 400 km) variation along the southeast coast of Australia. We also tested whether satellites and weather stations accurately detect the duration, frequency and number of extreme temperature events. Daily mean satellite SSTs and weather station air temperatures were significantly and strongly correlated with intertidal water and air temperatures, respectively (water: r 2 = 0.62, air: r 2 = 0.63). Nevertheless, depending on location, daily satellite SSTs were up to 6.7°C, and on average 1°C, higher than in situ water temperatures, while daily maximum air temperatures measured by weather stations were up to 23.2°C, and on average 4.2°C, lower than in situ air temperatures. At all locations, the frequency, duration and number of days greater than 30°C, as well as rates of temperature change, were all significantly lower when measured by weather stations. These differences suggest that satellite SSTs and weather stations are ineffective at capturing extremes in intertidal water and air temperature variability. We reinforce the argument that in situ measurements that focus on biologically relevant variation are the only legitimate means of predicting the effects of temperature change on intertidal taxa. KEY WORDS:Temperature data logger · Intertidal invertebrate · Remote sensing · Climate change · Extreme temperature events Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 439: 83-95, 2011 84 mussels and barnacles compared to water temperatures during high tide (Hofmann & Somero 1995, Somero 2002. Therefore, both air and water measurements are required to characterise the thermal environment of rocky intertidal shores.Several ecological studies have previously used satellite-derived SSTs to characterise the thermal environment of intertidal habitats (Barry et al. 1995, Broitman et al. 2001, Lagos et al. 2005, Herbert et al. 2007. Studies have shown that satellite-derived SSTs are highly correlated with daily in situ measurements of SST (Keogh et al. 1999, Barton & Pearce 2006, Smale & Wernberg 2009); nevertheless, satellite-derived SSTs are unlikely to reflect the variability of the temperature regimes experienced by the vast majority of rocky intertidal organisms (Helmuth & Hofmann 2001). Indeed, Helmuth & Hofmann (2001) found that aerial body temperatures of the mussel Mytilus californianus varied independently of water temperatures and suggested that water temperatures by themselves should not be used as a measure of temperature stress for intertidal organisms.Numerous factors operating across bot...

Assessing the Use of Area- and Time-Averaging Based on Known De-correlation Scales to Provide Satellite Derived Sea Surface Temperatures in Coastal Areas

“…The findings of this study are consistent with previous studies that have compared in situ temperature data from intertidal (Lathlean et al, 2011), subsurface (Pearce et al, 2006), and shallow waters (Smale and Wernberg, 2009;Stobart et al, 2016) with satellite SST data. However, all of these studies used either the closest satellite pixel to their study location (Malcolm et al, 2011;Baldock et al, 2014), an average of all the satellite data within an arbitrary distance (e.g., 20 km 2 box centered on logger location: Stobart et al, 2016), or number of pixels (Delgado et al, 2014) from the logger locations.…”

“…SST, however, may not be available for coastal areas due to contamination in the satellite-derived images [noisier radar returns from land and sea (Brooks et al, 1990) and improper instrument corrections (Shum et al, 1998)]. In addition, previous studies have demonstrated biases in SST data when comparing it to in situ measurements within coastal areas (Smale and Wernberg, 2009;Lathlean et al, 2011;Stobart et al, 2016), with some studies recording up to 6 • C differences (Smit et al, 2013). These biases are due to contamination of the satellite processing due to the presence of coastal features such as the shoreline, estuaries and embayments as well as complex coastal dynamics such as tides and upwelling (Smit et al, 2013) that vary over short spatial scales.…”

“…Lathlean et al, 2011), or an area averaged value whereby the mean SST measurements is calculated over a set number of pixels, including pixels offshore (Smit et al, 2013;Delgado et al, 2014;Stobart et al, 2016). Stobart et al (2016) assessed the daily temperature differences between satellite-derived and in situ measurements and averaged all the satellite-derived SST measurements within a 20 km 2 box centered on the in situ logger locations.…”

Protocolos para o monitoramento de habitats bentônicos costeiros - Rede de Monitoramento de Habitat Bentônicos Costeiros - ReBentos

“…Em costões rochosos, a utilização de sensores eletrônicos de temperatura, instalados em um gradiente vertical no mediolitoral, possibilita a medição contínua da variação de temperatura no micro-habitat, na tentativa de correlacioná-las às mudanças na estrutura da população, mais comumente de bivalves e cirrípedes, e aos dados ambientais que expliquem o comportamento termal desses organismos (Helmuth, 2002;Siviero, 2010;Lathlean et al, 2011). Mortalidade causada por estresse térmico depende não apenas da frequência de eventos de alta temperatura, mas também da taxa de aquecimento e resfriamento experimentado pelos organismos (Denny et al 2006) que, no caso dos sésseis ou sedentários, será determinada pelo horário das marés baixas, pelo grau de exposição às ondas e pelo clima (Harley & Helmuth, 2003;Harley, 2008;Mislan et al, 2009).…”

“…Mortalidade causada por estresse térmico depende não apenas da frequência de eventos de alta temperatura, mas também da taxa de aquecimento e resfriamento experimentado pelos organismos (Denny et al 2006) que, no caso dos sésseis ou sedentários, será determinada pelo horário das marés baixas, pelo grau de exposição às ondas e pelo clima (Harley & Helmuth, 2003;Harley, 2008;Mislan et al, 2009). Portanto, tentativas para prever o efeito de mudanças da temperatura em organismos do mediolitoral requerem medições in situ (Lathlean et al, 2011).…”