Estuarine macrobenthos in Calcasieu Lake,Louisiana: Community and trophic structure

Macrobenthic assemblages in Calcasieu Lake estuary (Louisiana) were sampled at 11 sites from October 1983 through November 1985. The sites were numerically dominated by subsurface-deposit feeders, consisting mostly of polychaetes. Greater densities of macrofauna were collected at the northern (upper) stations of the lake than were collected in West Cove or the southern stations. Abundances of polychaetes, oligochaetes, and amphipods at the upper lake stations accounted for most of the differences among stations. The numerical dominance by detritivores (97% of the fauna) and lack of strong sediment or salinity gradients across the estuary, resulted in an absence of temporal pattern in trophic structure of the macrofauna.     

Who are we responsible to? Locals’ tales of volunteer tourism

Existing studies have often suggested that volunteer tourism, with strong overtones of “social”, “justice” and “pro-poor” tourism, has the capacity to bring about positive impacts to local communities in host destinations. Wearing, for example, advocates volunteer tourism “as a development strategy leading to sustainable development and centering the convergence of natural resource qualities, locals and the visitors that all benefit from tourism activity” (Wearing, 2001: p. 12). Indeed, underlying assumptions in volunteer tourism suggest that it is a form of tourism that allows the empowering of locals in host-communities, and when compared to conventional modes of tourism, volunteer tourism allows cultural interaction and understanding to be developed between hosts and tourists in the longer period and more intimate form of contact. This, together with very direct and tangible outcomes of volunteer projects, appears to put in place a platform where locals and tourists both have the power to actively negotiate their identities and relations with each other.However, despite these deep-seated assumptions about the positive value in volunteer tourism, little empirical research has been conducted to assess the situation on the ground. Existing literature is largely centered on the volunteer tourist, with little works directly regarding the perspectives of host-communities. This places much uncertainty on whether the assumed benefits of volunteer tourism are indeed realized. Adopting a geographical approach, this paper begins with a review of existing discussions on the geographies of care and responsibility, and its intersections with literature on responsible tourism (of which volunteer tourism is often seen to be a part of). Opinions re-presented in this paper are based on interviews with 14 respondents in Cambodia (including local Cambodians, non-government organizations’ (NGO) and missionary workers that have previously hosted volunteer tourists in Cambodia. This paper thus explores both positive and negative opinions of volunteer tourism from the perspective of host-communities, and endeavors to contribute a balanced discussion to the limited literature regarding host-communities’ perspectives in tourism development.     

Phosphorus Burial in Sediments Along the Salinity Gradient of the Patuxent River,a Subestuary of the Chesapeake Bay (USA)

We used a sequential extraction technique and ²¹⁰Pb dating to determine the chemical form and amount of particulate phosphorus (PP) that is retained during burial in 1-m-long sediment cores collected along a salinity gradient from tidal freshwater to the mesohaline waters of the Patuxent River, a subestuary of the Chesapeake Bay. PP buried in the study sites with salinity values ≤3 was similar in concentration and form to PP entering the Patuxent from the watershed, suggesting efficient sequestration by the sediments at these low-salinity sites. PP extracted with citrate–dithionite–bicarbonate was the dominant form of PP at all salinities and all depths, and organic-P was the second most abundant fraction. We estimated that 81% of PP entering from the watershed is trapped in the sediments of the upper Patuxent subestuary and that the subtidal sediments retain three times as much PP as the marshes adjacent to the study sites.     

Phytoplankton-zooplankton coupling in the outer continental shelf and slope waters of the Mid-Atlantic Bight,June 1979

Measurements of phytoplankton distribution and production, and zooplankton abundance and biomass were made during the summer of 1979 along several shelf-slope transects in the Mid-Atlantic Bight. At the shelf-break, macrozooplankton (>200 μm) grazing was estimated to be sufficient to remove a substantial proportion of daily phytoplankton production. In contrast, on the shelf and in slope waters, where ciliates were abundant, estimates of macrozooplankton grazing indicated a consumption rate less than 15% of the daily primary production. Ciliate grazing, even at non-maximum rates, potentially could have consumed the entire daily primary production in all areas sampled. The findings indicate that the nature of the heterotrophic community is spatially variable in offshore waters even during summer conditions and could influence not only trophodynamic pathways but perhaps nutrient regeneration and recycling. This would be an important consideration in evaluating the fate of particle-bound chemcial species in the water column since fecal pellet producing zooplankton would affect rates of removal and sedimentation in a different manner than ciliates which produce non-compacted digestive debris.