Dr Philipp Boersch‑Supan

Marine & Quantitative Ecologist

Research Projects

Seabirds   Bayesian Inference   Seamounts & Islands   Open ocean  

Seabird Ecology 

Bioenergetics and foraging movements of Antarctic albatrosses

Albatrosses are the largest seabirds and top-predators of the open ocean, but their numbers are declining and many species are now endangered. I am using a combination of mathematical and statistical models and several decades of observational data to understand the factors affecting the population dynamics of these birds by studying their bioenergetics and foraging strategies.

Find out more about this project on the Albatross Project website.
Preprint: Sampling scale and movement model identifiability
Slides from my WSC2015 talk on metabolic models for albatrosses

Chick-provisioning in macaroni penguins 

With a global population of over 11 million individuals macaroni penguins are not only the most numerous penguins, but also the largest consumers of prey among all seabirds. I am using an automatic weighbridge to study body weights and foraging movements of marked and unmarked penguins at a study colony on Bird Island, South Georgia to better understand how macaronis forage during the breeding season and how they balance provisioning their chicks with the need to maintain their own body condition.

This work relies on a data base of several hundred thousand body mass time series. This poses computational challenges for data processing and analysis. I have addressed part of this challenge by creating an R wrapper for some very fast time series similarity search algorithms.

Paper: Boersch-Supan (2016): rucrdtw: Fast time series subsequence search in R
Software: rucrdtw: R Bindings for the UCR Suite

Bayesian inference for dynamic models of biological systems 

Differential equations (DEs) are commonly used to model the temporal evolution of dynamic systems in science and engineering, but statistical methods for comparing DE models to data and for parameter inference are relatively poorly developed. This is especially problematic in the presence of latent model states or parameters, when observations are noisy or when only a small number of observed time points are available.
Bayesian approaches offer a coherent framework for parameter inference that can account for multiple sources of uncertainty, while making use of prior information. This approach further offers a rigorous methodology modeling the link between unobservable model states and parameters, and observable quantities.

Paper: Boersch-Supan et al. (2016): deBInfer: Bayesian inference for dynamical models of biological systems in R
Software: https://github.com/pboesu/debinfer

Ecology of seamounts and islands  

Seamounts and islands protrude into the open ocean, introducing hard boundaries to an otherwise largely unbounded habitat. Above water, they offer breeding habitat for air-breathing marine predators such as seabirds and seals. Below the waves, the abrupt topography can trap small pelagic animals, exposing them to predators and/or concentrating them on island slopes and the summits and flanks of submarine banks. I have studied seabird assemblages on islands, as well as the effect of abrupt topography on the distribution of pelagic biota and their predator-prey interactions.

Borrelle, Boersch-Supan et al. (2016): Recovery of seabirds on islands eradicated of invasive predators
Letessier TB et al. (2016): Enhanced pelagic biomass around coral atolls
Letessier TB et al. (2015): Seamount influences on mid-water shrimps (Decapoda) and gnathophausiids …

Open ocean ecology 

Oceanic scattering layers & pelagic biogeography

A substantial proportion of biomass below the photic zone is concentrated in so called sound scattering layers which can be observed with echosounders. Scattering layers are often species-rich and include animals like laternfishes, squids and deep-water prawns. They are an important prey source for predators such as tuna, oceanic sharks and marine mammals. They also play an important role in marine biogeochemical cycles. I have studied the distribution and biogeographic zonation of scattering layers in the southern Indian Ocean.

Boersch-Supan et al. (2015): The distribution of pelagic scattering layers across the Southwest Indian Ocean
Boersch-Supan et al. (2012). Elephant seal foraging dives track prey distribution, not temperature …

Marine biogeography

I have also contributed to biogeographic studies of marine animals ranging from pelagic microbes to hydrothermal vent animals.

Djurhuus, Boersch-Supan et al. (2017): Microbial biogeography tracks water-mass features
Laptikovsky V, Boersch-Supan PH et al. (2015): Cephalopods of the Southwest Indian Ocean Ridge
Rogers et al. (2012): Discovery of Southern Ocean deep-sea hydrothermal vent communities