Past Research

Dr Justin Lathlean is a marine ecologist, currently based at Rhodes University, whose research focuses on the thermal biology and demography of intertidal invertebrates across broad and fine spatial scales.

PAST RESEARCH

Patterns of heat & desiccation stress in mixed mussel beds

In collaboration with Prof. Christopher McQuaid (Rhodes University), Dr Gerardo Zardi (Rhodes University), Prof. Laurent Seuront (CNRS, France), Terence Ng (Hong Kong University) and Dr Katy Nicastro (Universidade do Algarve, Portugal)

Recent research demonstrates that the gaping behaviour of the intertidal mussel Perna perna reduces heat and desiccation stress experience by mussels within conspecific beds (Nicastro et al. 2012). Within the mid-intertidal region of rocky shores of southern Africa, however, beds of P. perna are becoming increasing dominated by the invasive non-gaping mussel Mytilus galloprovincialis. It remains unclear whether increasing densities of M. galloprovincialis reduces the ability of P. perna to thermoregulate through their gaping behaviour.

'Robo-limpet'   (Cellana tramoserica)   used to measure   in situ   body temperatures.

'Robo-limpet' (Cellana tramoserica) used to measure in situ body temperatures.

Limpet orientation and heat-stress

In collaboration with Dr Clarissa Fraser and Assoc. Prof. Ross Coleman (University of Sydney)

Many ectothemic organisms can moderate their body temperatures by altering their orientation towards the sun. However, it remains unknown whether intertidal organisms can thermo-regulate in this way. This project, led by Clarissa Fraser (USyd), uses a combination of infrared thermography and biomimetic technology to test whether body temperatures of the limpet Cellana tramoserica differ depending on orientation. 

 

Typical rocky intertidal community of southeast Australia.

Typical rocky intertidal community of southeast Australia.

Biogeography of southeast Australian rocky shores

In collaboration with Dr Russell McWilliam (University of Wollongong), Assoc. Prof. Todd Minchinton (University of Wollongong) and Prof. David Ayre (University of Wollongong) 

This research investigates the biogeographic variability of rocky intertidal shores along more than 2,000km of southeast Australian coast. Unlike most temperate regions, this work reveals that broad-scale community structure does not appear to vary with oceanographic factors such as SST and Chlorophyll a concentration. 

 

Use of infrared thermography in marine ecology

In collaboration with Prof. Laurent Seuront (University Lille-1)

Recent technological advances have resulted in the increased accuracy and affordability of portable infrared cameras, which has lead to a number of novel applications within marine ecology. This work reviews recent uses of infrared thermography within marine ecological studies, outlining some common practices and problems, as well as identifying future directions. 

 

Patelloida latistrigata  on top of the barnacle  Tesseropora rosea . Barnacles, such as  T. rosea , provide biogenic habitat for many organisms.

Patelloida latistrigata on top of the barnacle Tesseropora rosea. Barnacles, such as T. rosea, provide biogenic habitat for many organisms.

Availability / distribution of free space and heat-stress

Small-scale differences in the availability and distribution of free space on rocky shores has previously been shown to alter substratum temperatures (Lathlean et al. 2012). This work investigates whether changes in the availability and distribution of free space indirectly influences the limpet Patelloida latistrigata by modifying heat-stress.

 

 

' Robo-barnacle ' (Biomimetic temperature logger of the mid-intertidal barnacle  Tesseropora rosea ).

'Robo-barnacle' (Biomimetic temperature logger of the mid-intertidal barnacle Tesseropora rosea).

Biomimetic loggers

In collaboration with Prof. Ross Coleman (University of Sydney), Assoc. Prof. Todd Minchinton (University of Wollongong) and Prof. David Ayre (University of Wollongong)

Measuring temperature variability at the level of individual organisms is essential for understanding how populations and communities will respond to future climate change. Biomimetic loggers were designed and assessed in the field to mimic the body temperatures of three key intertidal species: the barnacle Tesseropora rosea, the limpet Cellana tramoserica, and the whelk Dicathais orbita.

 

 

Infrared image of a rocky intertidal shore during a summer low tide.

Infrared image of a rocky intertidal shore during a summer low tide.

Estimating extreme heat-stress

In collaboration with Assoc. Prof. Todd Minchinton (University of Wollongong) and Prof. David Ayre (University of Wollongong)

As the climate continues to warm extreme heat events are expected to be more frequent and intense resulting in negative impacts on ecological communities. This work develops a statistical model for hind-casting latitudinal variability in extreme heat-stress on rocky intertidal shores using meteorological data and in situ temperature measurements.

 

Infrared image of black and white settlement plates during aerial exposure deployed within the midshore region. Black plates are visualised as bright yellow / white colours whilst white plates are dark purple / blue.

Infrared image of black and white settlement plates during aerial exposure deployed within the midshore region. Black plates are visualised as bright yellow / white colours whilst white plates are dark purple / blue.

In situ thermal manipulations

In collaboration with Assoc. Prof. Todd Minchinton (University of Wollongong)

In order to accurately predict how populations and communities will respond to increasing temperatures ecologists need to be able to experimentally manipulate temperatures in the field. This research presents a simple method of deploying black and white settlement plates to manipulate substratum temperatures experienced by rocky intertidal organisms.

 

 

Juvenile  Patellodia latistrigata, Tesseropora rosea  &  Catomerus polymerus.

Juvenile Patellodia latistrigata, Tesseropora rosea & Catomerus polymerus.

Early life history processes

In collaboration with Assoc. Prof. Todd Minchinton (University of Wollongong) and Prof. David Ayre (University of Wollongong)

The transition of benthic invertebrates from the pelagic larval stage to the sessile adult stage is wrought with difficulties. Typically, less than 5% of all individuals that settle survive to reproductive maturity. Thermal stress, amongst other abiotic factors, is thought to be a major influencing determinant. This work, which forms the basis of Dr Lathlean's PhD thesis, examines the effects of small- and large-scale temperature variability on the settlement, early post-settlement mortality and recruitment of the intertidal barnacle Tesseropora rosea