title: Human,climatic and oceanographic influences on the marine environment of Pohnpei, Federated States of Micronesia

authors: Phillip, Naiten Bradley, Jr.

subjects: coral reefs

abstract: Coral reefs and marine resources are culturally, as well as economically, vital to Pohnpei, situated in the Federated States of Micronesia (FSM). Farming and fishing are the main sources of livelihood for most Pohnpeian communities.  Pohnpei has eleven Marine Protected Areas (MPAs) where nine are situated in the Pohnpei Island Lagoon and two MPAs on the outer low-lying atolls.  Like many other Pacific Island countries Pohnpei is on the verge of creating more MPAs.  However, the marine environment continues to be significantly threatened by human and natural influences.  The recognised threats are yet to be methodically investigated.

This thesis used a combination of sediment, coral, fish, climatic, and oceanographic data, and focused on the Pohnpei Lagoon, examining a range of natural and human issues in the marine environment both at the local level (focusing on that within the Pohnpei Lagoon) and regional level (focusing on the western Pacific region).

Evidence from historical, archaeological, and modern experience has influenced various marine impacts that have altered the coastline and the marine environment of the Pohnpei Lagoon.  Humans have greatly impacted on the coral diversity and fish populations in the Pohnpei Lagoon by over-fishing and contributing to accelerated sediment inputs. My study findings shows that that increased sea surface temperature (SST) caused by El Ni o events is not the only cause of coral bleaching, but also cooling of SST, and other human factors.  However, when corals bleach they recover by  symbiont shuffling .  This is an ingenious way in which corals host one or more varieties of their zooxanthelle (Symbiodinium symbiont clades) that are more tolerant of the stress caused by increased SST and human factors.

The recognised natural climatic variability, particularly the El Ni o/Southern Oscillation (ENSO), may pose a significant threat to the Pohnpei Lagoon. El Ni o events are associated with: a change in trade winds and stronger wind gusts attributed to typhoons; lower rainfall causing drought; a decrease in SST attributed to cooling of the marine environment; increase of salinity in marine estuaries affecting development and recruitment of marine species communities; and a steep fall in sea level exposing corals to other elements.  The various on-going human threats and El Ni o-like conditions have caused giant clams (Tridacna gigas) to become extinct, have endangered herbivorous fish populations, and caused coral bleaching by cooling of SST.  

Although high SSTs are normally blamed for coral bleaching, the last major bleaching event in Pohnpei (2002) was likely to be due to a reduction in salinity (freshwater runoff and lower sea level), and there has been strong recovery. However, decreasing water temperatures rather than increases of SSTs may contribute to coral bleaching in the Pohnpei Lagoon and the Micronesian region. The Micronesian region appears to have suffered relatively few episodes of regional coral bleaching events. This is due to the  Western Pacific Warm Pool  (WPWP) where sea surface temperatures exceed 29 C but also where various feedback mechanisms limit the maximum SSTs.

The management aims of Pohnpei's MPAs are to move forward, while still respecting traditional practices. However, a lack of scientific monitoring, technical support and funding restricts our understanding of human and natural influences on the existing MPAs and the Pohnpei Lagoon. With respect to our policy makers the findings of the present research have implications on the future work in Pohnpei's marine environment and for policy makers, to make more-informed decisions before establishing new MPAs.

My key recommendations were:  1.) Integrate coral and fish monitoring during and after El Ni o events to understand El Ni o effects on the Pohnpei environment.  2.)  Undertake herbivorous fish investigation into their populations inside and outside the MPAs.  3.) Do not cut down vegetation along coastline areas, as it prevents erosion 4.)  Investigate Symbiodinium coral clades in Pohnpei Lagoon and the outer low-lying atolls.

text: Human,climatic and oceanographic influences on the marine environment of Pohnpei, Federated States of Micronesia Coral reefs and marine resources are culturally, as well as economically, vital to Pohnpei, situated in the Federated States of Micronesia (FSM). Farming and fishing are the main sources of livelihood for most Pohnpeian communities.  Pohnpei has eleven Marine Protected Areas (MPAs) where nine are situated in the Pohnpei Island Lagoon and two MPAs on the outer low-lying atolls.  Like many other Pacific Island countries Pohnpei is on the verge of creating more MPAs.  However, the marine environment continues to be significantly threatened by human and natural influences.  The recognised threats are yet to be methodically investigated.

This thesis used a combination of sediment, coral, fish, climatic, and oceanographic data, and focused on the Pohnpei Lagoon, examining a range of natural and human issues in the marine environment both at the local level (focusing on that within the Pohnpei Lagoon) and regional level (focusing on the western Pacific region).

Evidence from historical, archaeological, and modern experience has influenced various marine impacts that have altered the coastline and the marine environment of the Pohnpei Lagoon.  Humans have greatly impacted on the coral diversity and fish populations in the Pohnpei Lagoon by over-fishing and contributing to accelerated sediment inputs. My study findings shows that that increased sea surface temperature (SST) caused by El Ni o events is not the only cause of coral bleaching, but also cooling of SST, and other human factors.  However, when corals bleach they recover by  symbiont shuffling .  This is an ingenious way in which corals host one or more varieties of their zooxanthelle (Symbiodinium symbiont clades) that are more tolerant of the stress caused by increased SST and human factors.

The recognised natural climatic variability, particularly the El Ni o/Southern Oscillation (ENSO), may pose a significant threat to the Pohnpei Lagoon. El Ni o events are associated with: a change in trade winds and stronger wind gusts attributed to typhoons; lower rainfall causing drought; a decrease in SST attributed to cooling of the marine environment; increase of salinity in marine estuaries affecting development and recruitment of marine species communities; and a steep fall in sea level exposing corals to other elements.  The various on-going human threats and El Ni o-like conditions have caused giant clams (Tridacna gigas) to become extinct, have endangered herbivorous fish populations, and caused coral bleaching by cooling of SST.  

Although high SSTs are normally blamed for coral bleaching, the last major bleaching event in Pohnpei (2002) was likely to be due to a reduction in salinity (freshwater runoff and lower sea level), and there has been strong recovery. However, decreasing water temperatures rather than increases of SSTs may contribute to coral bleaching in the Pohnpei Lagoon and the Micronesian region. The Micronesian region appears to have suffered relatively few episodes of regional coral bleaching events. This is due to the  Western Pacific Warm Pool  (WPWP) where sea surface temperatures exceed 29 C but also where various feedback mechanisms limit the maximum SSTs.

The management aims of Pohnpei's MPAs are to move forward, while still respecting traditional practices. However, a lack of scientific monitoring, technical support and funding restricts our understanding of human and natural influences on the existing MPAs and the Pohnpei Lagoon. With respect to our policy makers the findings of the present research have implications on the future work in Pohnpei's marine environment and for policy makers, to make more-informed decisions before establishing new MPAs.

My key recommendations were:  1.) Integrate coral and fish monitoring during and after El Ni o events to understand El Ni o effects on the Pohnpei environment.  2.)  Undertake herbivorous fish investigation into their populations inside and outside the MPAs.  3.) Do not cut down vegetation along coastline areas, as it prevents erosion 4.)  Investigate Symbiodinium coral clades in Pohnpei Lagoon and the outer low-lying atolls.

year: 2010

title: Modelling heat transfer during chilling and freezing of packaged foods in industrial refrigeration facilities

authors: Hoang, Duy

subjects: Modelling

abstract: Industrial refrigeration equipment companies are continuously looking for ways to optimise the design of chilling and freezing tunnels in order to minimise food quality loss and increase the energy efficiency of the equipment. However, possibilities for dedicated experimental tests of the industrial operations are limited due to a large amount of food product involved while the number of design variables to be considered is high. A cost-effective alternative to experiments is numerical modelling. The main goal of this research was to simulate heat transfer of packaged food products in a chilling and freezing tunnel. Computational fluid dynamics (CFD) models were developed to improve prediction in industrial cheese chilling and chicken freezing. The industrial cheese chilling model was developed based on six blocks of agar that mimic the product arrangement and airflow pattern of a cheese chiller; while the chicken freezing model represents the first case of a CFD freezing model where the geometry was derived empirically via computed tomography scan data. The model predictions were validated by experimental temperature histories generated as part of the study. Once validated, the model was used to investigate the cooling heterogeneity and the effect of different operating conditions on the processing time. In addition to the CFD model, a simple heat transfer simulation based on the one-dimensional finite difference method was developed for industrial users. Thermal property models in the literature were also reviewed to propose the most suitable choice for thermal processing calculations.

text: Modelling heat transfer during chilling and freezing of packaged foods in industrial refrigeration facilities Industrial refrigeration equipment companies are continuously looking for ways to optimise the design of chilling and freezing tunnels in order to minimise food quality loss and increase the energy efficiency of the equipment. However, possibilities for dedicated experimental tests of the industrial operations are limited due to a large amount of food product involved while the number of design variables to be considered is high. A cost-effective alternative to experiments is numerical modelling. The main goal of this research was to simulate heat transfer of packaged food products in a chilling and freezing tunnel. Computational fluid dynamics (CFD) models were developed to improve prediction in industrial cheese chilling and chicken freezing. The industrial cheese chilling model was developed based on six blocks of agar that mimic the product arrangement and airflow pattern of a cheese chiller; while the chicken freezing model represents the first case of a CFD freezing model where the geometry was derived empirically via computed tomography scan data. The model predictions were validated by experimental temperature histories generated as part of the study. Once validated, the model was used to investigate the cooling heterogeneity and the effect of different operating conditions on the processing time. In addition to the CFD model, a simple heat transfer simulation based on the one-dimensional finite difference method was developed for industrial users. Thermal property models in the literature were also reviewed to propose the most suitable choice for thermal processing calculations.

year: 2020

title: Voices of the land: Richard Nunns in conversation with Martin Lodge

authors: Nunns, Richard

abstract: Richard Nunns in conversation with Martin Lodge

text: Voices of the land: Richard Nunns in conversation with Martin Lodge Richard Nunns in conversation with Martin Lodge

year: 2008